Abstract:
An in-situ on-line detection device and detection method for a long-distance metallurgical liquid metal component. The detection device comprises a front-end high-temperature resistant probe (18), a middle-end optical sensing device (19) and a back-end control platform (24), wherein the head of the front-end high-temperature resistant probe (18) is placed in a liquid metal (22), the tail thereof is coaxially connected to the middle-end optical sensing device (19), and an optical window (15) is arranged in the connection position; and the middle-end optical sensing device (19) is connected to the back-end control platform (24) through a signal line (25). The detection device and detection method can provide a timely and valid message for quality control and a melting end, so that the detection time is greatly shortened, the detection distance can be adjusted extensively, the measurement result is accurate, and it can be achieved to measure components that are difficult to measure, such as C, S, P, etc.
Abstract:
The present invention relates to a TDMA access method and device based on multiple access points. According to the problems that the existing method cannot simultaneously satisfy the demands of timeliness and reliability in actual industrial application and has low resource utilization rate, the present invention takes full consideration of the transmission characteristics and industrial automation application characteristics of wireless networks, and provides a TDMA access method and device based on multiple access points. The main ideas of the method in the present invention are: the multi-access point redundant communication manner is adopted to improve system reliability, beacon frames of multiple access points are utilized to perform time synchronization so as to improve synchronization precision, confirmation messages are fed back with regard to reliable access points to reduce the number of retransmissions, and a modularized multi-access point device design method is adopted to lower the difficulties of device maintenance and management.
Abstract:
A method for two-stage packet aggregation facing wireless sensor network with hybrid topology structure includes: building various nodes in a wireless sensor network into a hybrid topology structure which combines the star topology and mesh topology; establishing a two-stage packet aggregation architecture for periodic sensor data based on the above described topology structure; determining the packet format, aggregating and disaggregating the two-stage packets based on the topology structure and aggregation architecture; according to the application, the aggregated nodes in the network configuring router nodes and aggregation attributes of the nodes; according to the aggregation attribute, the sensor nodes performing the first-stage aggregation and generates an first-stage aggregation packet; according to the aggregation attributes, the router node implementing second-stage aggregation and generating a second-stage aggregation packet; the aggregation nodes taking charge of disaggregating the aggregated packets. The present invention adopts the above described hybrid topology structure, designs a two-stage packet aggregation method, decreases the overhead of packet-head, reduces the energy consumption of the nodes and inter-node interference, and saves communication resources.
Abstract:
A connnunication method for a mesh and star topo1 ogy structure wireless sensor network (MSTN) includes these steps: various nodes in a wireless sensor network are arranged in a mixed mesh and star topology structure; an IEEE 802.15.4 based superframe structure is defined on the basis of the topology; a 1ong-period data processing method, a connectivity measurement method, a medium access control method, a channel measurement method, a frequency hopping method, a beacon frame format and a two-phase communication resource distribution method are defined on the basis of the topology and superframe structure; a network construction method are defined on the basis of the topology structure, the superframe structure and the methods; a communication method which can implement the MSTN communication process is constructed on the basis of the network constmction method.
Abstract:
A method for two-stage packet aggregation facing wireless sensor network with hybrid topology structure includes: building various nodes in a wireless sensor network into a hybrid topology structure which combines the star topology and mesh topology; establishing a two-stage packet aggregation architecture for periodic sensor data based on the above described topology structure; determining the packet format, aggregating and disaggregating the two-stage packets based on the topology structure and aggregation architecture; according to the application, the aggregated nodes in the network configuring router nodes and aggregation attributes of the nodes; according to the aggregation attribute, the sensor nodes performing the first-stage aggregation and generates an first-stage aggregation packet; according to the aggregation attributes, the router node implementing second-stage aggregation and generating a second-stage aggregation packet; the aggregation nodes taking charge of disaggregating the aggregated packets. The present invention adopts the above described hybrid topology structure, designs a two-stage packet aggregation method, decreases the overhead of packet-head, reduces the energy consumption of the nodes and inter-node interference, and saves communication resources.
Abstract:
A connnunication method for a mesh and star topo1 ogy structure wireless sensor network (MSTN) includes these steps: various nodes in a wireless sensor network are arranged in a mixed mesh and star topology structure; an IEEE 802.15.4 based superframe structure is defined on the basis of the topology; a 1ong-period data processing method, a connectivity measurement method, a medium access control method, a channel measurement method, a frequency hopping method, a beacon frame format and a two-phase communication resource distribution method are defined on the basis of the topology and superframe structure; a network construction method are defined on the basis of the topology structure, the superframe structure and the methods; a communication method which can implement the MSTN communication process is constructed on the basis of the network constmction method.
Abstract:
The present invention provides an AP handover method based on double wireless network interface cards. A mobile terminal actively scans the signal strength of an AP, compares the scanned signal strength with the signal strength of a currently accessed AP, and if the signal strength is greater than the signal strength of the current AP, starts handover; otherwise, continuously scans till the handover succeeds. To reduce the handover delay and in accordance with the characteristic that the moving paths are basically fixed in industrial application scenarios, the present invention provides a pre-learning mechanism, that is, before formal application, information such as the location of the AP and the handover sequence in the application scenario is learned and stored in a terminal node, so that specific scanning and handover can be implemented in formal application. The present invention solves the problem of rapid AP handover in the industrial mobile network scenario, the double wireless network interface cards are used to achieve handover without interruption, and the pre-learning mechanism is used in specific industrial application scenarios, so the scanning delay is further reduced.