| With RFID technology development scale unceasingly expands, the functional requirements of RFID system is becoming more and more complex, but because of the huge amounts of RFID raw data, and no reliability, repeatability and existing the problems of the complexity of data management, result in the RFID system acquired by the upper application information isn’t consistent with the actual physical world, in order to reduce the case of such functional failure occurs, the data acquisition and processing is put forward higher request. This dissertation combines the science and technology plan projects of Guangdong province named Maternal-infant safety and surveillance (MISS) system based on RFID technology research, in the specific understanding of the field of RFID technology research and application at home and abroad,on the basis of combining with the project the actual needs of MISS system, the application of RFID technology in the system has carried on the detailed study, probes into the MISS system design, system middleware, data acquisition and processing oriented communication layer optimization design and implementation, and optimization design for cross read data processing.MISS system with RFID technology as the core, the active RFID tags integrates infrared temperature detection and vibration detection sensor, can take the initiative to launch a frequency signal, when it enters the reader’s radio frequency (RF) field, the reader device to receive an electronic tag information, coding, and then through the hospital local area network (LAN) transmits to a Hospital Information System (HIS) on data analysis and business process, the upper application through the Information System of data Information query and identification for the center with event detection, achieve real-time monitoring of maternal and infant. This system centered on maternal and infant safety, to adopt a baby infallible prevent stolen, error and temperature monitoring measures, through the application of RFID, by precision of the sensor network, take the initiative to make perfect and rigorous identification on neonatal and follows the detection.In order to block the differences between the RFID tag information and the upper application input requirements, MISS system middleware is divided into two levels:the data layer and logical layer. The data layer is designed to access and communicate with the RFID devices for data exchange. MISS system data exchange between the reader and the server via TCP/IP protocol to achieve. Logic layer is the core of the design of RFID middleware, implements the analysis of the data and the management of equipment. Logic layer through access to the data layer, RFID data obtained, and the combination of a number of letters and numbers of original nonsense according to the definition of communication protocol decoding. In this paper, in the design of middleware, before protocol parsing of data stored in the database, those data also need to be filtered, mining operations, and those data completed analysis and information added will be repackaged sent to the database.When MISS system detects an abnormal event realized, there will be a relatively fast and relatively slow data synchronization data conflict. In this paper, through a test to MISS system of evidence, analyzes its existing problems, and combined with the application system to the original data acquisition and processing, the optimization design of a data communication layer based on message passing mechanism. The data communication layer is designed into an asynchronous layer, queuing layer and synchronous layer, the introduction of the multiplex,buffer queue and the thread pool technology, through the integration of the three kinds of technology to achieve overall communications layer architecture.When the RFID reader in the system’s physical environment densely deployed, simultaneously detect multiple reader to "cross" phenomenon of the same label data in the same area, i.e., the detection region and the actual configuration of the space has a space unit mismatch phenomenon, which will lead to RFID system to produce large amounts of redundant data,and at the same because label has a particular space simultaneously by multiple reader configuration area to detect data information, not sloppy custom ownership between label and reader, and thus can’t guarantee the uniqueness of the object is to identify the relative positioning of the label, which is the upper application caused a heavy burden. MISS system applied in the hospital, in obstetrics and gynecology monitored area,, wards, corridors and entrances for each channel are to be arranged at the RFID reader, in order to solve this problem intensive reading RFID data cross RFID reader deployment environment under existing mismatch caused by the space in half the space limit (Semi-constraint, SC), to extract valuable information from RFID data stream and efficient data read processing to meet the needs of the system-level applications, label attribution problem based on the performance requirements of the system standard positioning analysis in case of spatial mismatch was defined as "cross read arbitration" problem. On the analysis of the original simple arbitration method, propose a quadratic cross read the arbitration method through value of expectation obtained by weighting method based on time under an efficient data structure auxiliary, this method takes the label attribute RSSI (signal strength) value as the basis, combining with the historical record of the label, the source of RFID data stream in a simple arbitration later after a second, can more effective obtain reader attribution of marked object and detect the relative location information of the object being identified. |
