2271 results about "Changing trend" patented technology

The invention belongs to the technical field of energy conservation, and relates to a variable frequency energy-saving control method for a refrigeration system. The control method comprises the steps of: determining the mass flow of a refrigerant according to the change or change trend of cooling load, then determining consumed power of a compressor which satisfies the flow, predicting the minimum condensation pressure which ensures that the thermal load of a condenser satisfies the cooling load and the power change of the compressor through an established energy-saving control mathematical model, and gradually adjusting the power frequency of the compressor to ensure that the rotating speed of the compressor reaches a predicted value; and adjusting the opening degree of an expansion valve to ensure that the condensation pressure reaches to be lowest, realizing the minimum pressure difference operation between the condenser and an evaporator, and ensuring that the operation energy consumption of the refrigeration system is lowest. The method solves the optimizing control problem of the compressor, the expansion valve and a fan in the system, utilizes the energy-saving control mathematical model to perform joint regulation on controllable factors (such as the rotating speed of the compressor, the opening degree of the expansion valve, and the air volume of an outdoor unit) of the operation of the system, ensures that the refrigeration system operates at a best operating point, and realizes the further energy conservation of the refrigeration system based on the variable frequency regulation.

Provided is a technique for classifying stocks into business sectors by calculating, for each of multiple exogenous variables, a measure of a tendency for a value of a stock to change as a result of a change in a data value for each such exogenous variable. The foregoing step is then repeated for each of several different stocks. Finally, the different stocks are grouped into different sectors based on similarities of such measures of tendency to change.

The invention relates to the fault diagnosis technology of a variable-frequency air conditioner and discloses a fault diagnosis control method for the variable-frequency air conditioner. The fast diagnosis and the precise positioning on the fault of the variable-frequency air conditioner are realized. The method comprises the following steps that a, corresponding control instructions are sent to the variable-frequency air conditioner through an intelligent control module for controlling the operation state of the variable-frequency air conditioner; b, a data collection module carries out real-time monitoring on the operation state of the variable-frequency air conditioner and collects environment parameters and operation parameters of the variable-frequency air conditioner; c, a fault diagnosis module calculates the environment parameters and the operation parameters of the variable-frequency air conditioner collected by the data collection module to obtain operation state curves of each part and the integral operation state curve of the variable-frequency air conditioner, then, whether the variable-frequency air conditioner has faults or not is judged according to the change trend of each curve, and the fault reason and the fault device are judged when the fault exists; and d, fault diagnosis results are displayed through a display module. In addition, the invention also discloses a fault diagnosis control system of the variable-frequency air conditioner, and the fault diagnosis control system is applicable to the fault diagnosis and the maintenance on the variable-frequency air conditioner.

A T-BOX information security detection and protection method based on vehicle anomaly data monitoring comprises: classifying and summarizing vehicle faults, providing a universal vehicle fault tree model, collecting and comparing vehicle real-time data through T-BOX, monitoring vehicle anomaly data in real time, transmitting to a telematics service platform (TSP) constantly, determining change trends of operation parameters and states of each vehicle part and system through data fusion and through big data analysis based on vehicle driving historical information collected by a cloud terminal and vehicle main parts related information restored by a main engine plant, comparing vehicle real-time information transmitted by T-BOX, judging whether a vehicle has anomaly data or not at present, and determining whether the vehicle is under information security attack or not based on the established vehicle fault tree model; finally, notifications or warnings on fault problems due to vehicle functional security need to be made for users and vehicles by the TSP.

The invention discloses a network fault diagnosis method based on deep learning in a network virtualization environment. The network fault diagnosis method comprises the steps of: dividing a network into a physical network and a virtual network, combining the characteristics of occurrence of network faults, considering the time influencing factor, network topological connection characteristics and a mapping relation between the virtual network and the physical network, and comprehensively evaluating the network faults by means of a fault severity grading probability; regarding network characteristic parameters with influence degrees as a model learning resource, paying attention to the correspondence between variation trend of network historical data and fault tags, establishing a network fault diagnosis model with multiple fault grading probabilities in the network virtualization environment based on a viewing angle of deep learning, and training network parameters by using the network fault diagnosis model; and adjusting a fault prediction model in the training process, and utilizing an optimized and adjusted deep learning network to realize fault diagnosis in the network virtualization environment. The network fault diagnosis method can carry out deep analysis on the network parameters in the network virtualization environment, therefore the network fault diagnosis method has higher precision in predicting the network faults.

The invention provides an isolated island operation detection method of photovoltaic grid-connected generation system which includes: a control device detects voltage frequency of grid-connected point, judges voltage frequency of grid-connected point whether reaching frequency protection threshold, if yes, a start anti-isolated island protection signal is outputted; if not, frequency signal of grid-connected current instruction is calculated by using double positive feedback active frequency deflection method, and the frequency signal is outputted; the double positive feedback active frequency deflection method is that obtained grid-connected point voltage frequency deflection relative to average frequency is used as first positive feedback, and change trend of frequency deflection is used as second positive feedback, feedback magnification factor of first positive feedback is adjusted. The method realizes isolated island detection rapidly, simulation and experimental result, isolated island detection time is shorten in 0.10s, 0.13s, grid-connected current harmonic distortion THD are 2.06%, 2.97% respectively, and has advantage over traditional method in isolated island detection speed and reducing interference to power network.

A photosensor system is provided which includes a photosensor array constituted by two-dimensionally arraying a plurality of photosensors, a driver circuit for supplying a drive signal to the photosensors, and a controller for controlling a reading operation of a subject image and a sensitivity setting. Before the start of normal reading operation of a subject image, a pre-reading operation of changing the image reading sensitivity at a plurality of stages for respective rows is executed. A row in an optimal image reading state is easily determined based on the dynamic range distribution of the lightness data of read image data or a dynamic range distribution from which an abnormal value deviating from the main change trend of lightness data is removed, and the linearly differentiated value of the dynamic range. An image reading sensitivity set for this row is set as an optimal sensitivity.

The invention discloses a topic detection and tracking method based on microblog data. In the method, potential hidden subjects in large-scale social network information are mined. The method comprises the following steps: firstly, partitioning microblog data increasing massively according to time sequence properties, and filtering redundant information; secondly, analyzing and classifying text contents in time windows, returning key subject descriptions with independent semantics after extraction, and extracting topics in different time windows; and lastly, analyzing the inheritance and the identity of topics among the time windows to conclude the variation tendency of microblog topics. According to the method, the dynamic developing process of topic contents, namely, the generation, development, climax and extinction of topics can be shown, and topics are described more accurately and fully.

The present invention provides an urban traffic system state visualization evaluation method based on traffic flow characteristics. Said method includes the following steps: A, in specific road section collecting real-time signal waveform whose continuous time is not less than three months, forming traffic flow state parameter; B, making traffic flow state parameter undergo the process of signal filter treatment so as to obtain traffic flow sample population; C, calculating average value and standard difference of all the samples in sample population, and using ratio value of standard difference and average value as sample discrete coefficient; D, according to traffic flow multidimensional state parameter strong aggregation characteristics forming and optimizing standard characteristic-phase plane graph for evaluation; and E, placing historical data, current data and predictive data of traffic system on the standard phase graph, and visually distinguishing running state of traffic system and its change tendency.

The invention discloses a method and a device for caching contents of videos by an edge node server. The method comprises the following steps that the edge node server makes statistics on the popularity degree of each video in a present statistic period of popularity degrees and stores contents of videos which do not exist in a current local cache and of which the popularity degrees are higher than a first threshold into a first cache; the popularity degree change trend of each video in the first cache is determined; the contents of the videos of which the popularity degree change trends are attenuated are transferred into a second cache; and whether the contents of the videos in the second cache are eliminated are determined according to the sequence of the popularity degrees in the present statistic period of popularity degrees, of various videos in the second cache. As the edge node server determines whether the videos are cached in the local area according to the popularity degrees of the videos, and whether the videos in the local cache are eliminated are determined by combining the popularity degree change trend of the videos, so that the problem that CPU (Central processing Unit) resources of the edge node server are wasted due to frequent deletion operations is avoided as far as possible, and the utilization rate of a caching space of the edge node server is ensured.

The invention relates to a mountainous area highway landslide risk evaluation model. The method is based on the theory of fuzzy mathematics, uses fuzzy comprehensive evaluation method, Delphi method, analytic hierarchy process and other methods to calculate the membership influencing hazard and vulnerability of highway side slope so as to obtain index evaluation level of hazard and vulnerability of slide slope risk, on the basis, adopts method of risk evaluation matrix to carry out risk evaluation of talus side slope. The model can predict, recognize, assess and analyze the slide slope risk of side slope that is possible to meet, and on the basis effectively cope with the risk to avoid or reduce the hazard of landslide geological disaster on national economy and life and property of people, and can take measures such as corresponding prevention and treatment on the basis of judgment and prediction of development and change trend of the landslide body.

The invention discloses a wireless network location method, device and system. The method comprises A. requesting monitoring data of a receiver device in a reference network on terminal visible base station signal strength from a reference network central server according to received terminal location request information; and B. locating a terminal according to the monitoring data returned from a dynamic fingerprint prediction model and the reference network central server. The wireless network location method, device and system can timely monitor and capture dynamic change trends of signal strength in a neighboring environment at the receiver device by introducing the reference network composed of a reference receiver device, and enables dynamic signal strength data (namely dynamic fingerprint information) to be used for on-line real-time location. Influences on positional accuracy of complex and dynamically-changed environmental factors on a traditional fingerprint location method based on a static fingerprint data base are weakened to a large extent.

The invention relates to a lightning striking fault identifying method of a direct current power transmitting line traveling wave protection. According to the characteristic difference of voltage traveling wave shape between the formed faults and unformed faults, two-pole voltage traveling wave weight and origin direct current weight are used to identify changing trend of the wave shape; ratio of a initial traveling wave mode maximum value and the second mode maximum value is used for representing saltation that the wave shape is cut; combining the two characteristics to achieve the identification of the voltage traveling wave while not causing the faults by lightning pole tower, lightning striking lightning line, lightning striking line shift central distance and the voltage traveling wave of non-lightning short circuit fault by the lightning pole tower, lightning striking line shift central distance. The interference and identification of the two lightning weaves are combined to improve the identifying reliability. A large number of emulations represent that this method is reliable and effective. The physical conception of this invention is intuitionistic and clear and has a rapid action function. The invention does not be influenced by the fault type and transition resistance and it is easy to achieve and suitable for apllying to direct current system protecting device.

A detached island effect test method and a device based on active frequency deviation relate to a test method and a device to test distributive new energy grid integration power supply, in particular to a detached island effect test method and a device based on active frequency deviation. Regarding the utility model, 25 cyclic waves form a major cycle. Chopped wave rate cf of the first 15 cyclic waves is 0, and variance trend of the frequency is tested. Under the circumstance that frequency tends to rise, frequency disturbance with the chopped wave rate of cf is added in the grid frequency in the last ten cyclic waves, and initial value cfmax of the chopped wave rate cf is positive. Under the circumstance that the frequency tends to reduce, frequency disturbance with the chopped wave rate of cf is added in the grid frequency in the last ten cyclic waves, and initial value cfmin of the chopped wave rate cf is negative. By adopting the invention, not only the operation probability of the detached island tested is improved; but also testing time is reduced, and current harmonics injected into the grid is reduced.

The invention provides a large structure horizontal planar displacement automatic measuring device and a method thereof. The automatic measuring device consists of a laser alignment emitter, a natural light filtration drone, a light spot position collection device, and a computer in which measuring software and database are installed. The natural light filtration drone is connected with the computer by the light spot position collection device. The laser alignment emitter consists of a flexible connection device and a shield, thus constituting a self-erect structure. The light spot position collection device transmits the collected variations in light spot colors, shapes and gradients to the computer which processes the variations and outputs measurement results. The large structure horizontal planar displacement automatic measuring device is applicable for detection and monitoring of distortion and movement of such large structures as bridges, cable support towers or buildings and so on. Vibration frequency, vibration amplitude of a point at any time can be detected and monitored. The automatic measuring device can be used for measuring and computing static and dynamic displacement and distortion, as well as computing and evaluating long-term displacement, distortion, and change trend thereof. The automatic measuring device has the characteristics of quick measurement, great interference rejection, high stability and so on.

The invention discloses a power battery temperature management method of an electric automobile. The power battery temperature management method comprises a battery temperature deducing method, a battery temperature optimum work region regulating method, a battery overtemperature prevention management method and a battery undertemperature prevention management method. A management system determines the battery work mode according to the charging and discharging current condition of a battery; the battery temperature change trend of the battery after heat radiation and heating measures are used or when the heat radiation and heating measures are not used is calculated according to the battery heat radiation and heating strategies; the battery heat radiation and heating strategies are selected, so that the battery temperature is maintained in the optimum work region or is similar to the optimum work region. The power battery temperature management method of the electric automobile has the following characteristics that the battery temperature is maintained in the optimum work range to the greatest degree; the use strategies and the heat radiation and heating strategies of the battery are systematically combined, so that the work stability of the battery is guaranteed; except for a special condition that a user cannot realize charging, the condition of automobile charging incapability due to too low temperature can be avoided.

Disclosed is a method for estimating an available bandwidth of a network. A plurality of periodic time-stamp packets are transmitted to a receiving-party communication apparatus, which is connected to the network, through the network at a currently-set test transmission rate, and then a changing tendency of transmission delay time differences between the time-stamp packets is checked on the basis of reception times at which the receiving-party communication apparatus have received the respective time-stamp packets. When the transmission delay time differences are located outside a stable range and show a tendency to increase, the test transmission rate is set to a decreased value and the time-stamp packets are repeatedly transmitted at the decreased rate and when the transmission delay time differences are located outside the stable range and show a tendency to decrease, the test transmission rate is set to be an increased value and the time-stamp packets are repeatedly transmitted at the increased rate. A test transmission rate is determined as the available bandwidth when the transmission delay time differences are within the stable range.

The invention relates to a metal powder laser rapid prototyping technology, in particular to a temperature field detecting method and the system device in the working process of the rapid prototyping of the metal powder. The invention adopts dual wavelength infrared image colorimetric temperature measuring method, the optical filters in two wavelengths are alternately arranged in the gathering optical path at different times, the image in the fused bath from two different wavelength are continuously and orderly gathered, and the color matching calculation of the gradation of the two infrared image from different wavelength are performed, according to the relationship between the color matching value and the temperature value, the temperature value of each point of the image is acquired, the temperature value is represented by the tonal value and a gradation image is formed, the gradation image then is processed, and the shape and temperature changing trend is acquired. By adopting the invention, the temperature distribution and the changing trend of the temperature field of the fused bath can be detected in real time during the rapid prototyping process of the metal powder, and then the temperature of the work piece process parameter can be adjusted in real time.

The invention provides a side slope stable reliability sensitivity analysis method based on Monte Carlo simulation. The side slope stable reliability sensitivity analysis method based on the Monte Carlo simulation includes: step 1, constructing a joint probability density function of uncertain parameters; step 2, using a Monte Carlo simulation method to obtain a side slope failure probability, and obtaining a failure sample; step 3, designing various sensitivity analysis schemes, and respectively constructing joint probability density functions of uncertain parameters under all the sensitivity analysis schemes; step 4, obtaining side slope failure probabilities under all the sensitivity analysis schemes; step 5, obtaining a variation trend of the side slope failure probabilities along with statistical characteristics of the uncertain parameters according to the side slope failure probabilities under all the sensitivity analysis schemes. The side slope stable reliability sensitivity analysis method based on the Monte Carlo simulation is wide in application range, simple in computation process, high in computation efficiency, and capable of effectively revealing a response regularity between the reliability level of a side slope and the statistical characteristics of the uncertain parameters, and has certain guiding significance for side slope risk control, design optimization and the like.

The invention discloses a construction method of a flat shoal flow prediction model based on joint control of upstream-downstream borders over a lower reach. The construction method specifically comprises the steps of adopting a one-dimensional hydrodynamic model to calculate and study a water level-flow relation curve of each fixed section in the reach; determining flat shoal flow in each section according to flat shoal elevation in each fixed section; adopting a method based on the combination of geometric average of logarithmic transformation and weighted average of section spacing to calculate the flat shoal flow of reach dimension; analyzing a response relationship of the flat shoal flow adjustment on an upstream water-sediment condition and downstream water level change, and constructing the prediction model based on joint control of the upstream-downstream borders over the lower reach. According to the construction method of the flat shoal flow prediction model based on joint control of the upstream-downstream borders over the lower reach, the calculated and obtained flat shoal flow of reach dimension is capable of better describing the flow passing capacity of the whole reach, and thus the flat shoal flow is more representative; the constructed flat shoal flow prediction model is capable of well reflecting the variation trend of the flat shoal flow along with the upstream water-sediment condition when the downstream water level changes sharply, and thus the constructed flat shoal flow prediction model has a guidance significance in the flood prevention and riverway management.

The invention provides a prediction method for complete machine performance decline trend of an aeroengine, and the prediction method comprises the steps of: firstly determining typical parameters required to be monitored of the aeroengine under different working conditions, carrying out preprocessing and similarity transformation, then amending the discharge temperature of the aeroengine, and finally calculating the discharge temperature margin, wherein the engine is needed to be returned to the factory for overhaul when the discharge temperature margin is 0. By adopting the method, key parameter data of the engine can be collected by utilizing data collecting hardware conditions equipped on an existing plane, and the engine performance change trend is predicted on the basis of the data, so that the available resources are sufficiently utilized, and the support is provided for the safety of the aeroengine.

The embodiment of the invention discloses a screen shot method and device and a terminal, and belongs to the field of human-computer interaction. The method is applied to the terminal with a foldabledisplay screen, the terminal comprises a first shell, a second shell and a connecting assembly, the connecting assembly is used for connecting the first shell with the second shell, and the foldable display screen is arranged on the first and second shells; the method comprises the steps of obtaining the folding angle of the foldable display screen in a folded state; monitoring a changing trend ofthe folding angle; if the changing trend of the folding angle is matched with a target changing trend, conducting screen shot operation on the current displayed content of the foldable display screen. According to the screen shot method and device, compared with the mode of conducting screen shot operation by pressing specific physical keys in a combined mode or clicking a screen shot control popped up on the display screen, a user can quickly complete the screen shot operation through simple folding and unfolding operation, the screen shot difficulty is low, the efficiency is high, and the efficiency of human-computer interaction is improved.

The invention discloses a low-frequency oscillation disturbance source positioning system and a method of a double-fed fan grid-connected system belonging to the technical field of power system stability analysis. The system comprises a sequentially connected information acquisition module, an oscillation source positioning module and an oscillation source position output module. The method comprises acquiring network structure parameters of a grid-connected system of a double-fed fan with virtual inertia control, The dynamic energy model of doubly-fed wind turbine with virtual inertia controlis constructed by injecting bus voltage, generator node current and load node current into the system. The dynamic energy of the components or branches in the oscillation process is obtained, and thepositive and negative and changing trend of the dynamic energy are judged to trace the disturbance source of the low frequency oscillation. A low-frequency oscillation disturbance source position canbe accurately locate by that invention, the function of the fan related control link in the low-frequency oscillation is taken into consideration, and the possible influence on the fan disturbance source is analyze.

The invention discloses a predicting method for short-term load of a power system. Active power of load data is used as a data basis; through dividing the data decomposing frequency to every stable frequency component from high to low, and then predicting a low frequency component and a medium high frequency component by a multiple linear regression and LSTM neutral network; finally, predicted results are overlapped to obtain a complete predicting result; thus the shortcoming that a traditional load predicting method is hard to effectively predict local features of the high frequency ; meanwhile, the change trend of the load can be exactly predicted, the predicting effectiveness under a complex condition is improved.