52 results about "Passive Method" patented technology

An aerial reconnaissance system generates imagery of a scene that meets resolution or field of view objectives automatically and autonomously. In one embodiment, a passive method of automatically calculating range to the target from a sequence of airborne reconnaissance camera images is used. Range information is use for controlling the adjustment of a zoom lens to yield frame-to-frame target imagery that has a desired, e.g., constant, ground resolution or field of view at the center of the image despite rapid and significant aircraft altitude and attitude changes. Image to image digital correlation is used to determine the displacement of the target at the focal plane. Camera frame rate and aircraft INS / GPS information is used to accurately determine the frame to frame distance (baseline). The calculated range to target is then used to drive a zoom lens servo mechanism to the proper focal length to yield the desired resolution or field of view for the next image. The method may be performed based on parameters other than range, such as aircraft height and stand off distance.

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 for exploring a region below the surface of the earth. The method comprises using a plurality of sensors to obtain seismic data obtained by recording ambient seismic interface waves in a frequency range whose lower limit is greater than 0 Hz, and whose upper limit is less than or equal to substantially 1 Hz. The sensors may be sensitive to three orthogonal components. Recordings may be made simultaneously by all sensors and normalization of data is unnecessary. The sensors may be moved and clean data may be selected. Local dispersion curves may be determined to improve vertical resolution. The data are processed so as to obtain a measure of the energy in a frequency band within the frequency range. The energy measure may be calculated by integrating the spectrum in the frequency domain over a desired frequency range. The resulting calculated energy provides information about the region of the earth being explored.

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.

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.

Low-frequency duct noise is relatively difficult to deal with by passive methods such as porous duct lining. Reactive methods like expansion chamber are rather bulky, while compact resonators are to narrow-banded. This invention shows that a suitably stetched thin membrane backed by a slender cavity can achieve a satisfactory performance from low to medium frequencies over an octave band.

A method and system for determining the status and monitoring an unattended individual. A radio beacon device can be associated with one or more individuals (e.g., an unattended person). Behavioral information about the individual(s) can be collected by tracking the location of the individual within a particular area (e.g., home, assisted living facility, etc.) utilizing the radio beacon device. The presence of other persons can then be distinguished from that of the individual within said particular area utilizing said behavioral information collected about said individual, thereby permitting a determination of the status of said individual and distinguishing the presence of other persons within said particular area. The behavioral information can include, for example, one or more activity levels associated with the individual.

A passive method for exploring a region below the surface of the earth. The method comprises using a single sensor located in turn at a plurality of locations to obtain seismic data obtained by recording ambient seismic interface waves in a frequency range whose lower limit is greater than 0 Hz, and whose upper limit is less than or equal to substantially 1 Hz. The data are processed so as to obtain a measure of the energy in a frequency band within the frequency range. For example, the seismic data may be filtered and may be subjected to amplitude normalization before being transformed into the frequency domain. The energy measure may then be calculated by integrating the spectrum in the frequency domain over a desired frequency range. The resulting calculated energy provides information about the region of the earth being explored.

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 relates to a bed bug detection device (10) comprising a refuge (16) which elicits a taxis response from bed bugs and a non-trapping indicator surface (18), on which the bed bugs may leave indicators of their presence, such as faecal matter or cast skins. The refuge is positioned in close proximity to said non-trapping indicator surface such that the bed bugs can leave an indicator of their presence as they travel across the indicator surface on their way to or from the refuge. Preferably the non-trapping indicator surface takes the form of a skirt which surrounds a refuge made of corrugated paper. The invention also provides a passive method of detecting the presence of bed bugs without their capture by detecting the presence of indicators rather than the bed bugs per se.

Passive control of fluid flow from a vessel is provided by a floating weir assembly. The assembly includes a float and a weir opening that is in fluid communication with an outlet from the vessel. The weir opening and the fluid path connecting the weir opening and the outlet are designed such that the rate of outflow is determined by the geometry and position of the weir opening. The weir opening is preferably vertically adjustable so that desired outflow rates can be specified.

Provided is an island detection method. A passive method and an active method are matched, an island can be detected out fast according to an overfrequency / underfrequency and an overvoltage / undervoltage method, and the quality of electric energy is not affected; when islanding occurs and power matching is formed in an island system, power matching of the system can be destroyed according to a capacitor switching method with harmonic detection as a criterion, voltage and frequency in the system are made to change, and consequently the island is detected out.

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.

Low-frequency duct noise is relatively difficult to deli with by passive methods such as porous duct lining. Reactive methods like expansion chamber are rather bulky, while compact resonators are too narrow-banded. This invention shows that a suitably stretched thin membrane backed by a slender cavity can achieve a satisfactory performance from low to medium frequencies over an octave band.

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 iconv(t) and voltage uconv(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 THDi=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 Cn2 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. Cn2 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 multifunctional heated scarf is provided as a means to evenly distribute heat to a user's neck and head in cold weather environments while additionally providing convenient compartments for storing and retrieving frequently manipulated items. The present invention accomplishes this through the integration of a plurality of compartments strategically distributed along the length of the scarf. The plurality of compartments enable improved distribution of the air activated heating elements while allowing a user to easily remove or reposition said air activated heating elements with ease. The present invention additionally provides compartments positioned at the extremities of the scarf that allow for rapid storage and retrieval of frequently manipulated items. The compartments include a passive method for securely storing various items within the interior space of the compartment. The combination of the aforementioned components and their distribution provide a multifunctional scarf that actively heats while functioning as a convenient storage system.

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.

Disclosed is a photovoltaic grid-connected island detection algorithm based on abrupt phase change and active phase shifting. The photovoltaic grid-connected island detection algorithm comprises the steps of (1) collecting a grid-connected current frequency value, a common point voltage phase and a grid-connected current phase through a phase-locked loop apparatus; (2) setting upper and lower threshold values of a frequency, a common point voltage and a phase deviation threshold value of a grid-connected current; according to national island detection standard, setting the frequency threshold valve |f-f0| to be less than or equal to 0.5Hz; and setting the phase difference |delta <phi>| to be less than or equal to 2 degrees; and (3) when the grid-connected current frequency, or the common point voltage and the phase deviation of the grid-connected current exceed the corresponding threshold values, starting island protection; and when the current frequency of the grid-connected point and the |delta <phi>| are not greater than the corresponding threshold values, applying phase perturbation, wherein theta<SMS> is equal to 5 degrees sin(pi / 2*delta f / 3), on an inverted output current until the current frequency of the grid-connected point or the |delta <phi>| is greater than the corresponding threshold value, starting island protection. By adoption of the photovoltaic grid-connected island detection algorithm, seamless switching of different algorithms can be realized; detection blind regions can be reduced while the detection speed can be accelerated when a passive method is adopted singly; and in addition, the power grid current THD can be lowered when an active phase shifting method is adopted singly.

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.