This paper presents an indoor positioning system (IPS) by using fuzzy estimation technique. The research aims to design an IPS with high stability, high accuracy and high reliability. The received signal strengths (RSS) sensed by ZigBee wireless sensors were used to estimate the object's position. All studies were experimented at a 10x10 square meters' indoor field. In all experiments, 361 positions (features) were estimated. From the experimental results shown, the fuzzy positioning technique proposed has the high accurate estimation even RSS signals are unstable. It is also clearly found that the positioning accuracy could be greatly improved when more wireless sensors are used in IPS.

This paper presents a fuzzy-based indoor positioning system (IPS) by using the information of neighbor points to estimate the location of object. An 8x8 square meters indoor area was used as the experimental area. In the experimental field, the received signal strength (RSS) of 288 points, 392 points, 440 points and 704 points were sensed and collected by a hexagonal positioning station which is composed of six printed-circuit board SPARKLAN AX-106M antennas and Zigbee module. The sensed RSS values are then used to be the information of fuzzy system for the object's position estimation. From the experimental results shown, the proposed IPS and fuzzy estimation method do have the accurate positioning performance and indeed has the potential in the real application.

This paper presents a sectored antenna array indoor positioning system (IPS) with neural network (NN) technique.The hexagonal positioning station is composed of six printed-circuit board Yagi-Uda antennas and Zigbee modules. The values of received signal strength (RSS) sensed by wireless sensors were used to be the information for object's position estimation. Two NN models, including NN with back-propagation (BP) learning algorithm and probabilistic NN (PNN), were applied to perform the positioning work for a comparison. In the experiments, an 8x8 square meters indoor scene was performed and 288 points and 440 points were experimented in this area. The positioning results show that both NN models have the average error less than 0.7 meter. In other words, the proposed positioning system not only has the high positioning accuracy, but also has the potential in real application.

No abstract

Multi-layer piezoelectric thin-film substrates which may have the properties of good temperature characteristic, high reflectivity, high coupling coefficient, high phase velocity, and integratible with semiconductor, have the potential to be used on acoustic devices. The properties of piezoelectric thin-film substrates are determined by the structures of the substrates, piezoelectric material, the metal film thickness and etc. Usually the acoustic wave parameters of the substrates are not readily obtainable from literature. In this paper, the acoustic wave properties of ZnO/Diamond/Silicon substrate was analyzed using finite element method. The data of this paper would be applied to design high frequency RF acoustic devices such as resonators and filters.