A method of railway system safety analysis based on cusp catastrophe model.

For rail transit systems, safety is one of the most important goals that need to be guaranteed. We build a method of railway system safety analysis based on the cusp catastrophe model. This method describes the continuous changing process of railway system safety and considers the emergent property of safety.

Novel accelerometer realized by a polarization-maintaining photonic crystal fiber for railway monitoring applications.

In this paper, we present a novel accelerometer based on the Sagnac interferometer configuration using a polarization-maintaining photonic crystal fiber (PM-PCF), which has a sensitivity of ~8 pm/G, and a resonant frequency exceeding 2.5 kHz. The proposed accelerometer is capable of functioning with a constant sensitivity in a large frequency range from 0 to 1 kHz which is much wider than many FBG-based accelerometers.

Large dynamic range pressure sensor based on two semicircle-holes microstructured fiber.

This paper presents a sensitive and large dynamic range pressure sensor based on a novel birefringence microstructured optical fiber (MOF) deployed in a Sagnac interferometer configuration. The MOF has two large semicircle holes in the cladding and a rectangular strut with germanium-doped core in the center. The fiber structure permits surrounding pressure to induce large effective index difference between the two polarized modes.