| With the rapid development of communication technology, detection technology,embedded technology, wireless sensor networks (WSNs) are widely used in manypractical applications. The information sensed by different sensor nodes not onlyhighly correlated in time, but also associated with space, it forms a new feature“Spatial-temporal correlation” in WSNs. Studying the temporal and spatial variationof WSNs can play an important role in the network scheduling, energy saving, faultdetection. On the other hand, fault detection is an inevitable product of networkreliability studies. Due to the gateway special status, the theoretical methods, andrealizing approaches of gateways abnormal detection are the difficulties in WSNs.Therefore WSNs Gateway abnormal detection based on spatial-temporal correlationhas important theoretical significance and practical application value.This thesis focuses on the characteristics of spatial-temporal correlation in WSNs,to the problems of gateway abnormal detection method difficult to determine, thenode working sequence after gateway abnormal hard to control, gateway abnormaldetection in MAC layer difficult to achieve and other problems, for the gatewayfault management, a real network experimental system is constructed to test theperformance in the industrial field. The main researches are summarized as follows:1. According to the WSNs information fusion process in monitoring area, from thetheory of signal correlation, building the basic structure of spatial-temporalcorrelation. And the time correlation function, spatial correlation function, timecorrelation coefficient, spatial correlation coefficient are constructed separately.Analysis the gateway state model and the gateway state evaluation function of nodecontribution evaluation function and parameters contribution evaluation function. Itprovides the theoretical basis for future work of gateway abnormal detection andspatial-temporal MAC protocol research.2. Study the gateway abnormal detection method. Analysis the existing problem ofthe gateway abnormal detection, To the problem of current and historical status information hard to compare, proposed the advanced sliding window method areextracted to historical character feature of the gateway state; And combined falsedetection rate, missing rate and calculation complexity analysis varieties of scientificmethod is compared, as a result, an improved distance-based outlier detectionmethod put forwards to achieve the gateway outlier detection.3. Study a spatial-temporal MAC (ST-MAC) protocol based on spatial-temporaltheory. This MAC protocol for the problems of node accessing, power controlling,time slot allocation, gateway abnormal detection and network abnormal controlling,proposed the mechanism of power adaptive control, time slot length dynamicallyallocation, gateway abnormal detection and etc. It provides a scientific and preciseimplementation technology of gateway abnormal detection.4. Innovatively constructed a set of spatial-temporal network system with thefunction of gateway abnormal detection. Propose the specific realizing method ofspatial-temporal correlation in sensor node and diagnosis node. Design software andhardware of sensor nodes, diagnosis node and gateway in the network, and proposedan actual meaning method for the application layer. It lays the foundation for thenext step practical industrial applications.5. Push the constructed spatial-temporal network system to specific industrialapplications and verify its performance in harsh environments. Include nodes lifetest and gateway abnormal detection test. Evaluate the influence of different numberof nodes and different sliding window lengths on the gateway abnormal detection.Verify the feasibility of the network system in the industrial field. And build apractical demonstration system in actual cold rolling continuous annealing unit.The full researches provide important theoretical basis and experimental supportfor gateway abnormal detection, and give a new idea in WSNs reliability study. |
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