255 results about "Stability conditions" patented technology

A system and method is disclosed in which a ranking function for a set of document rank values is iteratively solved with respect to a set of linked documents until a first stability condition is satisfied. After such condition is satisfied, some of the ranks will have converged. The ranking function is modified to take into account these converged ranks so as to reduce the ranking function's computation cost. The modified ranking function is then solved until a second stability condition is satisfied. After such condition is satisfied more of the ranks will have converged. The ranking function is again modified and process continues until complete.

(A1) A turbofan engine control system is provided for managing a fan operating line. The engine (10) includes a spool having a turbine housed in a core nacelle (12). A turbofan (20) is coupled to the spool (14). A fan nacelle (34) surrounds the turbofan and core nacelle and provides a bypass flow path having a nozzle exit area (40). A controller (50) is programmed to effectively change the nozzle exit area in response to an undesired turbofan stability margin which may result in a stall or flutter condition. In one example, the physical nozzle exit area is increased at the undesired stability condition in which the airflow into the engine creates a destabilizing pressure gradient at the inlet side of the turbofan. A turbofan pressure ratio, turbofan pressure gradient, low spool speed and throttle position are monitored to determine the undesired turbofan stability margin.

An apparatus and method for the kinetic analysis of tear interference is disclosed. The apparatus includes a light source for illuminating a tear film of a cornea, an optical train for modifying the light before it reaches the cornea and after it is the carrier of an image from the cornea, an image recorder to record a series of images of the illuminated tear film, and an image output for providing the series of images to a display; the series of images illustrating a tear film dispersion pattern indicative of a tear stability condition. The method includes the steps of illuminating the film on a cornea of said eye with light, recording a series of images of the illuminated film, and outputting the series of images to a display. The series of images illustrating at least one of a lipid film spread and a tear film dispersion pattern indicative of a tear stability condition.

A clock and data recovery system for detecting and resolving meta-stability conditions is provided. The clock and data recovery system includes a phase detector having logic configured to detect a meta-stability condition and to generate an output signal to mitigate the condition. The system can also include a time varying gain adjustment portion. This portion includes a gain control logic configured to determine and adjust system gain during reception of an incoming data stream. The system further includes a phase interpolator having increased linearity. The phase interpolator has a plurality of first branches having a differential transistor pair, a switch, and a current source, coupled between a first output and a first supply voltage and a plurality of second branches having a differential transistor pair, a switch, and a current source, coupled between a second output and the first supply voltage. The phase interpolator can also include an integrator portion.

The invention discloses an elastic wave forward simulation technology based on the space-time dual-variable grid, comprising the following steps: determining the stability conditions of the target area and the background area according to the speed parameter and the elasticity parameter of the underground medium aiming to the known earthquake geological model so as to calculate the size of the space grids with different dimensions and perform the discretization process to the speed field; obtaining the space arbitrary precision difference formula of the grid point variables with different dimensions by using the Taylor's formula and the finite difference technology, which is the arbitrary even order accuracy space difference formula of the space constant grid operator and the space variable grid operator, and calculating the wave field values of the precise division area, the rough division area and the middle transitional belt area by using the deduced space difference formula; in the wave field extrapolation process of the time layer, using different time sampling intervals to different grid division areas and meet the partial stability condition, obtaining the wave field value of the precise grid point in the precise time layer and the wave field value of the rough grid point in the global time layer; in each global time layer, transmitting the wave field value of the precise grid division area to the rough grid division area, thereby obtaining the space wave field value of the whole speed field at the said moment; performing the wave field extrapolation on each time layer by the said method and obtaining the forward simulation record of single cannon. The partial stability condition of the shallow layer can be met, so as to avoid the frequency dispersion noise.

An apparatus for processing passive acoustic signals received on a horizontal line array that were either emitted from an underwater object or echo returned from an object, is proposed to track the motion (bearing change and range change) of an object (target) relative to the receiver horizontal line array. Adaptive array processing for a moving object is biased for a moving source when the number of data samples is limited by the stationariness condition. Motion compensation can be carried out in the beam domain by beam shifting for a bearing changing object and frequency shifting for a range changing object. The method includes receiving acoustic signals from the target, determining the beam covariance matrices, determining the target bearing rate and range rate, processing the beam covariance matrices by compensating for the target motion, and producing a beam power plot versus time. Interference signal is suppressed when the interference source does not have the same motion (bearing and range rate) as the target. The method does not need detailed environmental acoustic information of the sound channel normally required to model the sound propagation.

Several embodiments of the present invention provide a capsule including a hydrophobic inner core layer and at least one hydrophilic outer layer. The outer layer may be seamless and may include at least one hygroscopic polyol and at least one polyol with a low hygroscopicity. The at least one outer layer may include at least one film or gel forming agent. Such capsules are stable and experience minimal or no degradation under accelerated stability conditions.

A system that incorporates teachings of the subject disclosure may include, for example, a method for detecting a plurality of use cases of a communication device, determining an initial tuning state for each of a plurality of tuning algorithms according to the plurality of use cases, configuring each of the plurality of tuning algorithms according to their respective initial tuning state, executing a first tuning algorithm of the plurality of tuning algorithms according to an order of execution of the plurality of tuning algorithms, detecting a stability condition of the first tuning algorithm, and executing a second tuning algorithm of the plurality of tuning algorithms responsive to the detected stability condition of the first tuning algorithm. Each tuning algorithms can control one of a tunable reactive element, a control interface, or both of one of a plurality of circuit components of a radio frequency circuit. Other embodiments are disclosed.

The invention provides a coordination control method for vehicle path tracking and stability. The method includes the following steps: step S1. performing vehicle modeling; step S2. performing estimation on a vehicle state and system interference based on Kalman filtering; and step S3. performing integrated control on the vehicle path tracking and stability. The method establishes a vehicle dynamics model and a path tracking model, and designs an estimation method of the vehicle state and steering system interference. An upper-layer controller is designed by using a sliding mode control method, which aims to ensure the stability of a vehicle itself while reducing course deviation and lateral deviation during a path tracking process. In a lower-layer controller, a method for optimal distribution of a wheel tire force is designed, and according to requirements of the upper-layer controller and combining yaw and roll stability conditions of the vehicle, directional control distribution ofthe wheel tire force is achieved. The coordination control method can ensure that a wheel independently drives the smart automobile to achieve a path tracking effect, and also ensures lateral and roll stability of the smart automobile itself.

A system that incorporates teachings of the subject disclosure may include, for example, a method for detecting a plurality of use cases of a communication device, determining an initial tuning state for each of a plurality of tuning algorithms according to the plurality of use cases, configuring each of the plurality of tuning algorithms according to their respective initial tuning state, executing a first tuning algorithm of the plurality of tuning algorithms according to an order of execution of the plurality of tuning algorithms, detecting a stability condition of the first tuning algorithm, and executing a second tuning algorithm of the plurality of tuning algorithms responsive to the detected stability condition of the first tuning algorithm. Each tuning algorithms can control one of a tunable reactive element, a control interface, or both of one of a plurality of circuit components of a radio frequency circuit. Other embodiments are disclosed.

An access point station responds to a request from a user station for contention-based access of a new traffic flow to a wireless transmission medium by applying a model of the wireless local area network to estimate delay that data packets will experience when delivered through the wireless network, in order to admit the new flow upon determining that admission will not violate quality of service requirements of neither the new flow nor of already admitted flows. For example, the access point station applies the model by determining an average packet inter-arrival rate, solving a system of nonlinear equations to determine probabilities of successful transmission, applying network stability conditions, computing an upper bound on queuing delay for the packets, computing a service delay budget for the packets, and computing an expected fraction of missed packets from the service delay budget.

The invention discloses a computer soft hardware system based on a variation multiscale method, belonging to the technical field of high-performance computers. The computer soft hardware system provides a behavior of describing a system bottom layer with a discrete model unit and a calculation mode of describing a stability condition observed by a large quantity of model unit group behaviors with variation restraint aiming at the multiscale structure and the discrete essence of a complex system in the actual world, thereby saving a large amount of calculated amount compared with simple bottom layer discrete simulation and outstandingly enhancing the calculation accuracy compared with single-level equalization simulation. Multilevel calculation hardware with the design directly reflects the calculation mode, adopts the interaction among a large quantity of simple processor calculation model units and acts on the variation restraint of the large quantity of simple processor calculation model units with complex general processor calculation, thereby outstandingly enhancing the resolving speed and the calculating scale of similar problems.

The invention discloses a method for evaluating simulation of full-size well wall stability. The method includes utilizing a full-size well wall stability simulator to apply confining pressure, pore pressure, horizontal pressure, overburden pressure, mud circulating pressure and drilling fluid circulating mediums required by an experiment on a rock core; measuring diameter expanding conditions of a rock core well in the process of the experiment through a well diameter measuring instrument (19); measuring acoustic wave feature changes of rock samples at a well wall after being soaked by drilling fluid under different circulating media in the process of the experiment through a stratum sliding wave sound speed testing system; directly observing actual changing conditions of the well after the well wall is soaked by the drilling fluid through a well wall visualizing and imaging system. The method has the advantages that downhole high-temperature high-pressure environment can be simulated more truly, stability conditions of the well wall can be evaluated dynamically, wellhole circulating media can be changed, the stability conditions of the well wall under different drilling modes can be evaluated, optimization of the drilling modes and drilling fluid systems is facilitated, and the method has high practicability and is convenient for popularization.

The invention discloses a fast two-stage filter algorithm applied to a high precision digital weighing sensor, which comprises the following steps of: (1) as required by system, selectively designing two filters and setting a stability threshold and a stability condition; (2) opening a first-stage filter for basic data smoothing and for fast tracking for data variation; (3) opening a second-stage digital filter for further smoothing data when data output of the first-stage filter meets the stability condition; (4) closing the second-stage filter when data output of the first-stage filter does not meet the stability condition in the weight increasing or weight decreasing process of the system; and (5) repeating the steps (3) to (4) until the measurement comes to an end. The fast two-stage filter algorithm of the invention realizes seamless dynamic cascade of the filters at two stages by the method of setting the stability threshold and the stability condition, and compared with the traditional two-stage digital filter cascading algorithm, shortens the time for the reestablishment of the filters in the weight increasing or weight decreasing process of the system.

The invention provides a steering engine saturation resistant self-adaptive control method for ship courses. The method comprises performing a mathematical description on ship course motion, and constructing a dynamic saturation-resistant compensator, a first state vector z1 of a self-adaptive backstepping controller and a Lyapunov function of the z1 to obtain virtual control; calculating a second state vector z2 of the self-adaptive backstepping controller through subtraction through combining ship course angle information, the course angular speed and the compensation state which is output by a dynamic saturation-resistant compensator module, constructing an overall Lyapunov function in the control method, and obtaining a ship course non-linear self-adaptive controller provided with the saturation-resistant compensator through combining ship course stability conditions to complete the ship course non-linear self-adaptive control method provided with the saturation-resistant compensator. The self-adaptive control method is explicit in thinking, clear and reasonable in structure and prone to engineering implementation.

The invention discloses a milling finish machining method based on the dynamic rigidity of an impeller blade. The dynamic modality of the impeller blade is obtained through a standard modal test, a flutter model is introduced to obtain a stability criterion, and reasonable machining parameters are acquired. The method comprises the followings steps of: 1, performing the modal test to measure the dynamic modality of the impeller blade; 2, building a milling stability model of the impeller blade; 3, studying the dynamic rigidity stability of the impeller blade; 4, obtaining a cutting stability condition under the dynamic rigidity of the impeller blade; and 5, verifying the cutting stability condition and adopting the finally optimized cutting parameters to machine. The problem of cutting flutter caused by milling of thin-walled parts such as the blade is solved by the method, and the machining stability is obviously improved by optimizing the cutting parameters. The method is suitable for finish machining of various thin-walled parts.

The present invention provides a two-layer or multilayer polymer electrolyte comprising a laminated arrangement of a first electrolyte layer for contacting and electrochemically stabilizing a positiveelectrode and a second electrolyte layer for contacting and electrochemically stabilizing a negative electrode. In the two-layer polymer solid electrolyte provided by the invention, a high-voltage stable polymer electrolyte layer is in contact with a positive electrode, and a low-voltage stable polymer electrolyte layer is in contact with a negative electrode. At the same time, the stability conditions of the positive electrode and the negative electrode are satisfied, and a wide redox window is obtained. In addition, the flexibility of the polymer helps to reduce the interfacial resistance.The present invention provides a novel strategy for the design and optimization of solid polymer electrolyte materials, in which a high-voltage positive electrode and a low-voltage metal negative electrode coexist in a battery by utilizing a two-layer structure. This new solid-state electrolyte design will greatly accelerate the development and commercialization of solid-state secondary batteries.

The invention discloses a micro-scale six-roller mill with static stability. The six-roller mill is characterized in that parallel positioning devices are utilized to position the axial lines of six rollers of upper and lower bearing roller systems (2, 7), upper and lower middle roller systems (3, 6) and upper and lower working roller systems (4, 5) in the same vertical plane, i.e., the offset distance among the six rollers is zero. A micro-scale mechanism with static stability is arranged between the upper and lower bearing roller system (2, 7); and a micro-scale eccentric shaft mechanism with static stability is arranged between the middle roller operating side end cover (35) and middle roller axial moving mechanism of the upper and lower middle roller systems (3, 6). In the invention, a rolling mill roller system can maintain the equivalent static-stability condition of a mechanism under the condition of alternating the running state of no load during rolling intermission and high load during rolling, and the dynamic micro-scale crossing behavior of two rollers of bearing base kinematic pair with a backlash under an external interference moment is prevented so that the radial loadings of each line of rollers of the columnar rolling bearing are uniformly distributed to prolong the service life, therefore, the safe and stable operation of the six-roller mill can be realized under a heavy-load and high-speed condition.

The invention relates to a nonlinear differential golden section self-adapting control method which comprises the following steps: (1) establishing a characteristic model in relation to the a single-input / single-output linear time varying system; (2) determining a nonlinear differential golden section self-adapting control law according to the characteristic mode; and (3) performing the stability analysis of the closed-loop system formed by applying the control law to the characteristic mode and determining the stability conditions of the closed-loop system. The method overcomes the disadvantages of the prior art, provides the characteristic model in relation to the linear time varying system, and achieves the effect of section self-adapting control method using the nonlinear differential golden. The self-adapting control method can track the fast-varying signal and the signal with mutation slope.

A turbofan engine control system is provided for managing a low pressure compressor operating line. The engine includes a low spool having a low pressure compressor housed in a core nacelle. A turbofan is coupled to the low spool. A fan nacelle surrounds the turbofan and core nacelle and provides a bypass flow path having a nozzle exit area. A controller is programmed to effectively change the nozzle exit area in response to an undesired low pressure compressor stability margin which can result in a stall or surge condition. In one example, the physical nozzle exit area is decreased at the undesired stability condition occurring during engine deceleration. A low pressure compressor pressure ratio, low spool speed and throttle position are monitored to determine the undesired stability margin.

A vehicle stability control system includes a signal collection sensor and a vehicle controller (10). The signal collection sensor is configured to collect a vehicle condition information parameter, and the vehicle controller (10) is configured to calculate a control yaw moment according to the vehicle condition information parameter. The control yaw moment is used to cancel a difference between an estimated yaw moment and an actual yaw moment. The vehicle controller (10) is further configured to determine according to the vehicle condition information parameter whether the vehicle (100) is in a stable region or a non-stable region in the case of tire blow-out, and allocate the control yaw moment to four wheels (101) according to a vehicle stability condition, thus implementing vehicle stability control. A vehicle stability control method and a vehicle (100) with the vehicle stability control system are also disclosed.

The invention relates to a special three-direction self-synchronizing vibrating screen and a determining method of structural parameters thereof, belonging to the engineering technical field of vibrating utilization. The invention provides a special three-direction self-synchronizing vibrating screen which can realize synchronization of two eccentric runners of a dual motor drive vibrating screen,and a determining method of structural parameters thereof; the special three-direction self-synchronizing vibrating screen comprises a supporting bracket, one end of a spring is fixed on the supporting bracket, the other end of the spring is fixed on a screen body which is provided with a screen cloth internally; two vibrating motors for driving the two eccentric runners are respectively arrangedon the screen body, rotating centers of two vibrating motors are symmetrical by taking a mass center of the screen body as the center, and the rotating planes of the two eccentric runners are parallel. The determining method of structural parameters of the special three-direction self-synchronizing vibrating screen comprises the following steps: 1): building a mathematical model of a system; 2) quasi-stable state electro-magnetic torque of the asynchronous motor is determined; 3) the capture condition of the frequency of dual rotors and the synchronous stability condition are determined.

The invention provides a modem and a network searching method thereof. The method includes sampling a signal level value and a signal quality value of a serving cell; and obtaining signal power conditions according to the signal level value and obtaining signal stability conditions according to the signal quality value. When the signal power conditions and the signal stability conditions are higher than preset conditions, a network searching state is determined to be a closing state. An embodiment of the modem and the network searching method can reduce power consumption and workload.

The invention provides a method for detecting coal property characteristics. The method comprises the following steps of: 1, performing industrial measurement on fire coal, thus obtaining as received basis moisture, air dry basis moisture, air dry basis fixed carbon, air dry basis ash content, air dry basis volatile component and as received basis lower heating value; 2, calculating as received basis fixed carbon, as received basis ash content and as received basis volatile component of the fire coal; 3, calculating as received basis fixed carbon heating value; 4, calculating as received basis volatile component heating value; 5, calculating the ratio of the as received basis fixed carbon heating value to the as received basis volatile component heating value, and recording the ratio as Kq; and 6, comparing the size of the Kq, wherein the larger the Kq is, the lower the combustion stability is. The heating value of the volatile component can be calculated according to the fixed carbon content and the lower heating value obtained through analysis, the ratio Kq of the fixed carbon heating value to the volatile component heating value is obtained, the ratio serves as the index of judging the combustion stability of the fire coal, and the combustion stability conditions of different coal types can be compared.

The invention discloses a large-span underground construction surrounding rock excavation stability monitoring and early warning method. The method comprises the steps that a surrounding rock monitoring section is selected, and section monitoring points are arranged; a surrounding rock deformation monitoring device and a stress monitoring device are installed; the surrounding rock deformation monitoring device and the stress monitoring device are applied according to the stability conditions of the surrounding rock at different stability stages, and the stress and displacement of corresponding monitoring points of the different excavation stages are monitored; the surrounding rock excavation displacement power load increasing rate eta i is determined and serves as the surrounding rock excavation stability evaluation parameter, and evaluating and early warning are conducted on the surrounding rock stability. The large-span underground construction surrounding rock excavation stability monitoring and early warning method has the advantages that the underground cavern surrounding rock excavation monitoring area stress change parameter and the corresponding displacement response parameter are organically coupled, the parameters can reflect the dynamic change rule of the surrounding rock stability along with the excavation construction, and analysis and prediction can be carried out on the future surrounding rock excavation deformation development rule and the stability evolutionary trend.

The invention belongs to the field of control over a permanent magnet synchronous motor, and relates to a speed regulating control strategy for a sensorless permanent magnet synchronous motor. The speed regulating control strategy is characterized in that a three-phase current of the permanent magnet synchronous motor is detected, the current under an alpha and beta coordinate system is obtained through Clarke conversion, and the current under the dq coordinate system is obtained through Park conversion; a sliding-mode observer is designed according to a mathematic model of the permanent magnet synchronous motor under the alpha and beta two-phase static coordinate system; a hyperbolic tangent function is used as a switching function; a sliding-mode face is selected; the estimation value of the rotor position is obtained through counter electromotive force; a speed estimator is adopted for estimating the speed; a Lyapunov function is selected, and an adaptive law is obtained through the stability condition; According to the speed regulating control strategy, the structural switching discontinuity is relieved, the buffeting is obviously weakened, the rapidness, the robustness and the dynamic performance are improved, when an error exists in the estimation value of the rotor position, the speed estimation error is made to be within the controllable range, and the rotating speed estimation precision is improved.

A piecewise linear method for analyzing supercavitation navigation body kinetic characteristics includes the steps that step1, a supercavitation navigation body kinetic model is built; step2, piecewise linear fitting is performed on a non-linear sliding force function in the supercavitation navigation body kinetic model to obtain a linear sliding force function; step3, parameters of the supercavitation kinetic model are set; step4, the supercavitation kinetic model with the piecewise linear sliding force Fp function is adopted for obtaining a sole balance point of a supercavitation navigation body, linearization is performed on a system at the balance point to obtain a jacobian matrix of the system and a characteristic equation at the balance point, characteristic values of the system are obtained, and the balance point of the system is judged to be an unstable saddle focus. By the adoption of the piecewise linearization of the sliding force function, the supercavitation navigation body kinetic model is simplified, so that the balance point position and stability conditions of the model have concise analytical expressions, and the supercavitation navigation body kinetic characteristics are analyzed more conveniently.

A small wearable recall device is provided to capture images triggered by a combination of a detection of a capture condition (e.g., changes in motion, temperature or light level) followed by a relatively stable period, as detected by an accelerometer. By triggering on the combination of a detected capture condition followed by a detected stability condition, a clearer image of the environment of an interesting event is expected to be captured. The small size of the recall device makes it possible to integrate it into common portable consumer products, such as MP3 players, purses, clothing, hats, backpacks, necklaces, collars, and other human-wearable products.