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A twin-resonance-coupling phenomenon and the sensing characteristics of a selectively fluid-filled microstructured optical fiber (SFMOF) are proposed and demonstrated. The SFMOF is realized by selectively infiltrating refractive index fluid into a single air hole located at the second ring near the core of the MOF. Twin-resonance dips are observed in the(More)
The Internet of Things (IoT), which is usually established over architectures of wireless sensor networks, provides an actual platform for various applications of personal and ubiquitous computing. Recently, moving target localization and tracking in an IoT environment have been paid more and more attention. This paper proposes a square-root unscented(More)
Internet of things (IoT) has provided a promising choice for structural health monitoring (SHM) recently. In vibration-based structural health monitoring, structural features which are extracted from periodically spaced measurement using sensors are subject to variable environmental conditions. This paper proposes an environmental effect removal based(More)
We propose in this paper a non-cyclic prefixed multiple-input multiple-output orthogonal frequency division multiplexing (non-cp MIMO-OFDM) system based on a recursive algorithm of joint channel estimation and data detection. Unlike in the traditional cyclic prefixed MIMO-OFDM system, the transmitted sequence of the proposed system is given in the way that(More)
A double-filled photonic crystal fiber (PCF) was fabricated by filling liquids of different indexes into two air holes in the cladding. The core mode coupled to the local cladding modes LP(01) and LP(11) in the 1310 and 1550 nm wavebands, respectively. Due to the unique characteristics of the mode coupling, the resonant peaks in different resonance areas(More)
Smartphone based activity recognition has recently received remarkable attention in various applications of mobile health such as safety monitoring, fitness tracking, and disease prediction. To achieve more accurate and simplified medical monitoring, this paper proposes a self-learning scheme for patients’ activity recognition, in which a patient only needs(More)
In a context sensing system in which a sensor-equipped mobile phone runs an unreliable context-aware application, the application can infer the user's contexts, based on which it provides personalized services. However, the application may sell the user's contexts to some malicious adversaries to earn extra profits, which will hinder its widespread use. In(More)
A tunable fiber polarizing filter based on selectively filling a single hole of a solid-core polarization maintaining photonic crystal fiber with high index liquid are proposed and demonstrated. Two groups of polarization-dependent resonance dips in the transmission spectrum of the single-hole-infiltrated photonic crystal fiber are observed. Theoretical and(More)
In recent years, human motion recognition based on smartphones has gotten increasing attention in many fields such as mobile health, health tracking and pervasive computing. However, motion recognition performance can be easily affected by variation of phone orientations and positions. Different users have influence on recognition accuracy as well. Most of(More)