1821 results about "Differential equation" patented technology

A virtual reality display system that generates display images in two phases: the first phase renders images based on a predicted pose at the time the display will be updated; the second phase re-predicts the pose using recent sensor data, and corrects the images based on changes since the initial prediction. The second phase may be delayed so that it occurs just in time for a display update cycle, to ensure that sensor data is as accurate as possible for the revised pose prediction. Pose prediction may extrapolate sensor data by integrating differential equations of motion. It may incorporate biomechanical models of the user, which may be learned by prompting the user to perform specific movements. Pose prediction may take into account a user's tendency to look towards regions of interest. Multiple parallel pose predictions may be made to reflect uncertainty in the user's movement.

The instant invention is a method for numerically propagating waves or solving wave equations on a digital computer. This invention can be used to compute highly accurate solutions to the wave equation, in fact in some cases it computes the analytical solution, something previously considered impossible. The instant method can also propagate waves that are not described by differential equations, such as anisotropic scalar waves. The invention has the advantages that it is computationally efficient, accurate, and flexible. Of importance is the ability to propagate waves that simulate the P-wave arrivals in both isotropic and anisotropic media with a scalar as opposed to a vector equation.

An e-book allowing note and corrigendum sharing as well as differential update is produced using vector graphics satisfying XML syntax, and a script program is embedded in or linked to the e-book. The script program allows a user to add various kinds of note markups to the e-book, including fluorescent marker, text annotation, handwriting note, bookmark, digital blackboard record, post-it note, highlight, voice, memo, tracking information, etc. The e-book also allows an e-book editor to correct any error in the e-book. The note markups and corrigenda may be uploaded via network, and be shared among other users by way of differential update.

The invention provides a vehicle autonomous parking path programming method used for multiple parking scenes. The method is used for automatically parking a vehicle in a parking space through an autonomous parking system when the autonomous parking system detects the available parking space. The method includes the steps that target parking space information is detected, and a parking scene is determined; the initial state and target state of the to-be-parked vehicle are determined; a vehicle kinematics differential equation is established; state variables and control variables of the vehicle are segmented, equidistance sampling is performed on each segment according to certain time step, and to-be-optimized variables are obtained; an equality constraint, boundary constraints and inequality constraints of the to-be-optimized variables are formed; motion range constraints of the to-be-parked vehicle are formed according to the motion range limit in the parking process of the vehicle; an optimization objective is determined, and an objective function is established; and by means of a nonlinear programming solver, an optimal solution of a parking path is obtained. The vehicle autonomous parking path programming method is suitable for the multiple parking scenes, the design is reasonable, abundant information can be provided so as to control autonomous parking of the vehicle, and the security coefficient is high.

The invention relates to receivers and methods for receiving multi-carrier differentially modulated signals utilizing iterative decision-directed differential detection. The receiver includes a decision feedback loop including a channel estimator for estimating inter-symbol channel variations, and a differential equalizer for correcting channel-induced errors in a differentially detected signal based on the estimated inter-symbol channel variations.

The invention relates to a moving target detecting method based on differential fusion and image edge information. The method comprises the following steps of: extracting a video image for preprocessing, and extracting the edge of the image to acquire continuous edge images; performing inter-frame differential operation on the continuous edge images respectively in a unit 8 data format, and performing background differential operation on the image in an intermediate frame; and fusing the detecting results of two differences to primarily extract a moving pedestrian target. In a background difference, a background automatic extracting method is improved, and a continuous-edge-image-based background image extracting and updating method is provided. A moving target area in the image is extracted by using an adaptive-background-model-based dynamic threshold value, and morphologic filtering and connectivity detection are performed, so that the foreground target of a moving pedestrian is acquired. Under the complex condition of sudden light variation, a moving target can be accurately and reliably detected, and the method is superior to the three traditional methods in the two aspects ofan identification rate and an error detection rate.

A signal detection and classification technique that provides robust decision criteria for a wide range of parameters and signals strongly in the presence of noise and interfering signals. The techniques uses dynamical filters and classifiers optimized for a particular category of signals of interest. The dynamical filters and classifiers can be implemented using models based on delayed differential equations.

The invention relates to a computer application in the field of control, monitoring, modification and/or optimization of processes which comprise real process sequences of discrete events, so-called "discrete event dynamic systems", which cannot usually be described by systems of (differential) equations. Such processes occur for example in technical developments as well as in other business activities in the industrial or tertiary sector. Such a real process is reflected in a process model which is connected to the real process via at least one interface. If the interface(s) is/are bi-directional, real process data can be transmitted into the model directly, i.e. without data conversion, and thus the real process can be monitored; in the model, simulations can be carried out with changed process data; and finally if the result of the simulation is successful, process modifications can be transferred directly to the real process.

A difference region extracting section 122 extracts differential regions based on screen data of a previous screen stored in transmission screen data storage section 124 and a current screen stored in a screen data storage section 121. A priority determining section 123 calculates change data density indicating a degree of a change of pixel values for every differential region. For example, when a user operates an icon on the screen, the change data density of the differential region corresponding to the icon becomes larger than the change data density of the differential region corresponding to the background portion of a video image. An encoding section 125 writes screen code data of each differential region in a transmission buffer 141 in descending order of the change data density.

A general, computational-mathematical modeling method for the solution of large, boundary-coupled transport problems involving the flow of mass, momentum, energy or subatomic particles is disclosed. The method employs a modeling processor that extracts a matrix operator equation (or set of equations) from a numerical transport code (NTC). The outputs of software codes, available for modeling physical problems governed by conservation laws in the form of differential equations, can be processed into closed-form operator equations with the method. Included is a numerical transport code functionalization (NTCF) model which can be determined numerically, based on a system of solutions of an NTC, evaluating outputs for a given set of inputs. The NTCF model is a linear or nonlinear, multi-variable operator equation or set of such equations. The NTCF model defines relationships between general, time-variable inputs and outputs, some known and some unknown, considered as boundary values. The user of an NTCF model can directly work with the processed model output, instead of running the original numerical code in general applications of a boundary-value problem. The numerical transport code functionalization model can be employed as a surrogate for representing the numerical transport code to provide a solution to the transport problem. The invention enables modeling efficiency and availability to be increased, while computational complexity and cost decreased. Computational times for complex modeling problems can, in some cases, be dramatially reduced, for example by several orders of magnitude.

A differential device is provided with a case being capable of rotation around a rotation axis; a differential gear set housed in and drivingly coupled to the case, which includes first and second output gears and is configured to differentially transmit the rotation of the case to the first and second output gears; a clutch configured to controllably limit and free a differential motion between the first and second output gears, which is housed in the case; an actuator configured to actuate the clutch; and a notifying member configured to notify whether the differential motion is limited or freed to an exterior of the case.

The invention provides a design optimization method and an optimization device of a power assembly mounting system. The design optimization method comprises the steps of establishing a differential equation of a space six-freedom degree vibration model of the power assembly mounting system; analyzing to obtain an inherent frequency, an inherent vibration mode and vibration energy coupling among six freedom degrees according to inherent characteristics of the differential equation for the power assembly mounting system; establishing a multiple target optimization function of the power assembly mounting system according to each order inherent frequency, inherent vibration mode and vibration energy coupling; and carrying out optimization design with a particle swarm optimization algorithm. A dynamical model and the optimization function of the power assembly mounting system are established, the multiple target optimization function with reasonable distribution of mounting modal frequency and decoupling degree of energy as targets is determined, and a parallel optimization multiple target algorithm is subsequently adopted to obtain a multiple target optimization scheme set of the power assembly mounting system so that the designed power assembly mounting system can best meet the performance requirements of energy decoupling and modal distribution.

Illumination lenses (1806, 1902, 2002, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 3006, 3100) having surfaces shaped according to given differential equations in order to distribute light in a highly controlled manner with minimum reflection losses are provided. Both primary lenses and secondary lenses are provided. The secondary lenses include outer surfaces that are defined as loci of constant optical distance from an origin at which a light source is located. Versions are provided of both the primary and secondary lenses having Total Internal Reflection (TIR) wings. These are useful in the case that narrower distributions of light are required. A method of refining the shape of the lenses to obtain more obtain lenses that produce better fidelity ideal light distributions is also provided.

Abstract of Disclosure A calibration factor for a sensor including a material-containing conduit and a plurality of motion transducers operative to generate motion signals representing motion of the conduit is determined from a normal modal dynamic characterization of motion of the conduit. The calibration factor may be generated by generating a solution to a modal differential equation of motion in a modal domain including a plurality of normal modes of motion of the conduit, and by generating the calibration factor from this solution. The normal modal dynamic characterization may characterize motion of the conduit as a function of a modal Coriolis term that describes coupling among a plurality of normal modes of the conduit responsive to mass flow in the conduit. The modal Coriolis term may be determined from a mode shape function that describes modal motion of the conduit as a function of location on the conduit. The invention may be embodied as methods, apparatus and computer program products.

An analytical apparatus for optimally combining measurements from N individual rate sensing devices or gyros into a single rate estimate significantly improves performance over that of any individual component device. Kalman filtering is used to combine rate sensed devices optimally in the sense of minimizing the variance of the rate error. The Riccati differential equation (RDE) associated with combining a collection of rate sensed devices is completely and exactly solved to derive to the matrix RDE. This analytic solution serves as the key for understanding all of the theoretical properties of the optimal filter, and provides a complete characterization of the final virtual rate sensed performance. In addition, the analytic RDE solution allows many practical problems to be solved that have proved essential for developing successful filter implementations. A discrete-time minimum variance filter implementation combines sensor measurements optimally.

The invention discloses a Beidou three-frequency non-differential non-combined observation value time transmission system and method. The method includes the steps that phase observation value, pseudo-range observation value, satellite ephemeris, earth rotation, antenna phase center and other parameters of China Beidou satellite navigation systems at two time transmission stations are obtained; data check, gross error reject and cycle slip detection are carried out, error models of ephemeris, tide, relativity, the earth rotation, atmosphere and antenna phase deviation are corrected; an ionospheric virtual observation model with additional ionospheric prior information constraints, spatial domain constraints and time domain constraints is constructed; and a three-frequency non-differentialnon-combinatorial precise single-point positioning model is constructed, a single-point positioning timing solution is carried out on corrected data, and comprehensive clock corrections of receivers of the two transmission time stations are obtained and compared to obtain a time transmission difference; and compared with standard time of one of the two transmission time stations, precise time of the other one of the two transmission time stations is obtained. According to the Beidou three-frequency non-differential non-combined observation value time transmission system and method, the observation noise can be reduced, and the accuracy and reliability of time transmission are improved.

The invention discloses a parallel partition electromagnetic transient digital simulation method of an AC and DC power system. The method comprises the following steps of: partitioning a target AC and DC power system into a plurality of subnets comprising an AC network subnet, a current converter subnet, a DC network subnet or an AC and DC mixed network subnet; acquiring equivalent impedance matrix and equivalent potential at port point of each subnet; acquiring current of the tie-line between the subnets; acquiring node voltages of each subnet according to the current of the tie-line between the subnets; solving differential equations of a generator, a control system, and the like of each subnet; processing a user self-defined model, an MATLAB model and input and output information of a physical device; processing input and output information of an electromagnetic transient interface. The simulation method has the advantages of flexible net partition mode, high computation speed, and the like. The simulation method can be simultaneously suitable for electromagnetic transient net partition parallel computation of an AC and DC system, parallel computation of electromechanical transient, accessing a user self-defined model, processing an MATLAB model and a physical device and the like, thereby realizing digital simulation of various transient and dynamic processes of the AC and DC power system.

A device capable of assisting an agent in taking a step even in the case where the leg motion of the agent is stagnant. It is determined whether the agent is in a first state in which the leg of the agent is moving or in a second state in which the leg of the agent is stagnant, on the basis of a value detected in response to the leg motion of the agent. If a transition from the first state to the second state is detected as the determination result, a value of a sustained energy input term is increased, where the sustained energy input term is contained in a simultaneous differential equation representing a second model for use in generating a second oscillator ξ₂, which is to be a control basis of an assisting force.

The invention discloses a trajectory tracking control method for a mobile robot based on a sliding mode variable structure. According to the trajectory tracking control method, advantages and disadvantages of different reaching laws are comprehensively analyzed, and a reaching law with better rapidity and stability is proposed and designed. The reaching law is composed of two items, wherein the first item is that the system state is controlled to rapidly approach to a sliding mode surface when being far away from the sliding mode surface, and the second item is that the system state is controlled to keep stable running in the sliding mode surface. The trajectory tracking control method comprises the steps of firstly building a kinematics model and a trajectory tracking error model of the mobile robot, and deducing a mobile robot trajectory tracking error differential equation; and then designing a switching function based on the sliding mode variable structure, and deducing a sliding mode control law according to the designed reaching law, wherein the control law can enable the mobile robot to rapidly converge to an expected trajectory and expected speed. It is indicated by MATLAB numerical simulation that the trajectory tracking control method can effectively weaken a chattering phenomenon in the tracking process and improve the trajectory running accuracy. In addition, the trajectory tracking control method has good stability and robustness.

A mathematical model specifically for diabetes may be generated which may be continuous in time, in that there are no discrete time steps, and any event can occur at any times. The model may be generated using differential equations, object oriented programming, and features. The model may be used to simulate patients who have contracted or may contract type 1 or type 2 diabetes, which greatly improves the efficiency of treating patients and designing clinical trials.

The invention relates to a precise orbit determination method of a navigation satellite for assisting a clock error between stations, which is characterized by comprising the following steps: configuring an atomic clock and a nanosecond stage time synchronization system at each station of an area network, receiving a distance measurement signal of a navigation satellite by each station of the area network to obtain the carrier phase data of each station, detecting the periodic trip generation moment of the carrier phase data by a Blewitt method and carrying out time synchronization between the stations by a two-way satellite time frequency transmission method TWSTFT to obtain a clock error between the stations; resolving a differential equation under an inertial coordinate system to obtain an orbit of the navigation satellite. Before orbit determination data are processed, the method firstly realizes the time synchronization between the stations with high accuracy (i.e.: obtaining the clock error between the stations). During the processing of the orbit determination data, an improved non-error method is adopted, only the orbit needs to be resolved, and the clock error between the stations does not need to be resolved, which not only can improve geometrical factors but also is beneficial to separating a system error (the clock error between the stations). Thus, the orbit determination accuracy can be enhanced.