35results about How to "Reduce the number of exchanges" patented technology

The invention relates to a hierarchical wireless sensor network time synchronization method and belongs to a wireless sensor network time synchronization method. The method respectively adopts different synchronization mechanisms aiming at response nodes and ordinary non-response sub nodes and adopts different estimation methods to calculate the clock offset and the clock frequency offset relative to reference nodes; the hierarchical time synchronization method is divided into two stages, namely a hierarchical discovery and sub node collection stage and a time synchronization stage, wherein during the hierarchical discovery and sub node collection stage, a hierarchical structure of a wireless sensor network is established, and the response nodes on each layer are determined through collecting sub node information; during the time synchronization stage, a maximum likelihood estimation method and a least square method are utilized for calculating the clock offset and the frequency offset between the sub nodes and the reference nodes, a clock is further compensated, and by parity of reasoning, the synchronization within a whole network range is finally achieved. The hierarchical wireless sensor network time synchronization method has the advantages that the synchronous message overhead is reduced, and the energy consumption is reduced; the time synchronization accuracy is improved; the expandability is enlarged on aspect of new node addition.

The invention relates to a multi-level cache sensitive indexing method for a database, and belongs to the technical field of efficient database query in computer databases. An index structure is divided into two levels by studying the behavior characteristics and the physical characteristics of different levels of storage media, and the different levels are specially optimized according to the difference of the storage media. The internal nodes of an index tree are similar to those of a B+ tree, and the node fan-out degree of the internal nodes is improved for the main memory-cache level according to a cache access mechanism by adopting an internal node division mode. By adopting a compression coding mode on keywords inside internal node subareas, the utilization rate of the main memory space utilized by the internal nodes of indexes is improved, and the cache hit rate is improved. The leaf nodes of the index tree are Bloom filters for establishing pages for storing keywords in a memory by adopting the Bloom filter technology in the probability theory based on the magnetic disk-main memory level, and are organized into index leaf nodes, so that the number of magnetic disk exchanges in the query process is reduced.

The invention discloses a novel balloon microcatheter for treating cerebrovascular stenosis. The novel balloon microcatheter is combined by a balloon catheter and a microcatheter. The balloon catheter is sleeved outside the microcatheter. An external cavity is formed by the inner wall of the balloon catheter and the outer wall of the microcatheter. A balloon is arranged at the front end of the outer cavity. The microcatheter is provided with balloon developing rings at two ends corresponding to the balloon. A tip developing ring is disposed at the tip of the microcatheter. The inner cavity of the microcatheter is used as a conveying system for a support. During operation, a doctor uses the balloon on the balloon catheter to pre-expand vascular stenosis and then withdraws the balloon, a balloon expansion support or a self-expandable support disconnects from the inner cavity of the microcatheter along with withdrawal of the balloon (the balloon expansion support needs to pushed forward slightly), and the balloon expansion support or the self-expandable support expands and fixes at the vascular stenosis to expand the vessel. By the novel balloon microcatheter, exchanging times of medical instruments inside a patient's body during operation can be reduced, and possibility of complications of the patient is lowered.

The invention discloses a method of maximum-minimum distance clustering-based distributed cooperation frequency spectrum sensing in a cognitive unmanned aerial vehicle network. A maximum-minimum distance clustering algorithm is utilized to divide cognitive unmanned aerial vehicles into a plurality of clusters, and cluster heads are selected in the clusters; all the cognitive unmanned aerial vehicles use energy detection to obtain sensing information of a main user; two-step fusion is carried out according to a clustering situation and the sensing information of all the cognitive unmanned aerial vehicles, and each cognitive unmanned aerial vehicle is enabled to obtain one piece of uniformly converged global sensing information; and a decision of whether the main user occupies a frequency spectrum is made according to the global sensing information. According to the method, communication of members in a cluster and a cluster head is ensured through dividing cognitive unmanned aerial vehicles with similar positions and similar mobility into the one cluster, the clustering algorithm reduces the number of information exchanges in distributed fusion, and detection efficiency is improved;and fusion of the global sensing information can be realized in a case of no fusion center through two-step fusion, the number of the sensing information exchanges is decreased, and fast and highly efficient frequency spectrum detection is realized.

The invention provides an equipment connection method, electronic equipment and a computer readable storage equipment. The method comprises the steps of obtaining historical connection records with other equipments; acquiring historical parameter information from the historical connection record; generating current parameter information according to the historical parameter information and dynamicparameter information corresponding to the current connection request; and establishing connection with the other equipment by utilizing the parameter information of this time. According to the method, the electronic equipment establishes the Bluetooth connection with other equipment according to the dynamic parameter information and the historical parameter information, and the electronic equipment uses the pre-recorded historical parameter information to reduce the number of times of information exchange with other equipment, so that the Bluetooth connection speed is increased, and the efficiency of using the Bluetooth function by a user is improved.

The invention discloses an artwork traceability system based on a block chain, which comprises a user module, a business service module and a data service module, and is characterized in that the usermodule is used for creating a block chain account of a user and cancelling, wherein the data service comprises a block chain node service, the business service comprises the account service, artworkservice, transaction service, delivery service and block service. According to the system, the artwork information is stored into the block chain nodes, the business service is called through a Restful interface, and a block chain platform is called through a smart contract to realize various business services, so that the defects in the prior art are overcome, the problems of traceability, rightconfirmation and transaction of the current artwork collection market are solved, and the transaction of the art collections becomes honesty and reliable.

The invention discloses an electronic business auction method. The method comprises the following steps of: acquiring and storing auction information carried by an auction request, wherein, the auction information at least includes bidding; acquiring original price of a commodity when commodity auction is finished; generating stochastic price according to the original price of the auctioned commodity; and acquiring the stored offered price of the commodity, comparing the offered price with the stochastic price, and selecting a buyer successful in auction. An electronic business auction device is correspondingly provided in the embodiment of the invention. The electronic business auction method and the device improve participation of buyers, increase interest of auction process, and activate atmosphere of electronic business systems, simplify user operation process, reduce man-machine exchange times, and improve processing efficiency of the system.

The invention discloses a fan-shaped train position-fairness-based wave beam transmission method applied to high-speed-rail wireless-communication. The method comprises the steps of: establishing a fan-shaped wave beam structure, and covering a railway by a base station through the N wave beams; using position information of a train to maximize average receiving power in a wave beam range, satisfying instantaneous receiving power stability of a train at different positions in the wave beams, and carrying out wave beam optimization on a scene of the train; for a scene where two trains meet, satisfying instantaneous receiving SINR stability of each train through maximizing a total transmission rate, and optimizing wave beam pairs; and carrying out offline calculation and storage on the wavebeams in all the scenes, and selecting a wave beam by the base station according to position information of a train for data transmission. The invention provides the wave beam transmission method, which is for high-speed-rail communication and about position-fairness, through fan-shaped wave beam coverage on a coverage area of the base station for covering the wave beams of a wider range, and impacts brought by Doppler frequency shift and path loss changes are overcome.

The invention discloses a preparation method of high-silicon Y-type molecular sieves, and belongs to the technical field of microporous materials. The high-silicon Y-type molecular sieves are preparedby taking a commercial NaY molecular sieve as a raw material and adopting a chemical dealumination-high-temperature roasting alternated use method. Some organic acids, inorganic acids and inorganic salts can be selected as dealumination agents for chemical dealumination, but the types of the acids need to be selected according to the dealumination sequence. Compared with the prior art, the NaY molecular sieve treatment process of the method has the advantages of simple process, low equipment requirement, good modification effect and the like, and can be used for preparing the modified high-silicon Y molecular sieves with various property requirements.

The invention relates to a service chain grouping and reforming method for mobile edge calculation, which comprises the following steps of: S1, establishing a mobile edge calculation system; S2, judging whether the edge node can provide the service function of the received service chain required by the user equipment or not by the Hash group manager of the edge node; S3, configuring all service functions in the service chain at the edge node; S4, configuring a part of service functions in the service chain at an edge node, and configuring the remaining service functions at a core network node; S5, configuring all service functions in the service chain at the core network node; and S6, reforming the group nodes. According to the scheme, user equipment requirements are grouped, one group only needs to be configured with one group of service chains, and users in the group share the service chains, so that the usage amount of flow entries when the service chains are configured is reduced, the possibility of group table overflow is reduced, the number of times of information exchange between edge nodes and core network nodes is reduced. Therefore, the delay of the control layer is reduced.

The invention discloses a data transmission method capable of realizing high-precision time synchronization, and aims to solve the problem of large-area faults caused by non-uniform time of electric power. The method comprises the following steps: constructing an improved cluster average clock synchronization method; supposing that the time for sending and receiving the information by the node isthe same and is a fixed value, setting the fixed value as d, broadcasting a synchronous beacon to all parts in the cluster by a transmitter in the cluster, and recording the local time for receiving the beacon by the parts; global average clock synchronization is realized through cluster averaging; a cluster average clock synchronization algorithm considering phase bias, frequency drift and randomtime delay; convergence analysis is carried out on the algorithm, so that the sensor network can gradually reach an average clock synchronization state through the algorithm.