Text Categorization for Authorship based on the Features of Lingual Conceptual Expression

PACLIC 21 / Seoul National University, Seoul, Korea / November 1-3, 200

Simulation of the performance of phase-sensitive OTDR based on ultra-weak FBG array using double pulses

A phase-sensitive optical time domain reflectometry sensing system based on Ultra-weak FBG Array using double pulses is proposed. The principle of this sensing system is elaborated. A series of simulations are carried out to optimize the parameters to increase the sensing distance of this system. The parameters contain reflectivity of UWFBG the interval between adjacent UWFBGs and pulse width. The optimal reflectivity and pulse width corresponding to different grating space are found out to achieve a longer sensing distance

Analysis of partial-body and whole-body static sitting comfort

The whole-body comfort sensation was moderately to highly correlated with local body part comfort sensation in both sitting and driving, in order to understand what exact relationship exists between them, the seating comfort evaluations under the stimulus of four body parts (i.e. backs, waist, hips and thighs) were carried out for 15 subjects separately, subjective ratings on both partial-body and whole-body comfort are derived under different conditions. Impact factor (IF) of the partial-body comfort to whole-body comfort is calculated by the linear regression method, and the main variables are obtained by the stepwise regression algorithm. The most significant local body part in influencing whole body comfort is found at the region of hips, followed by backs, waist and hips. With impact factor analysis on partial body comfort, the results show that the local comfort feeling of waist is most potential to be influenced by other body parts, while the comfort sensitivity of thighs is the lowest

Quantized Feedback Control of Network Empowerment Ammunition with Data-Rate Limitations

This paper investigates quantized feedback control problems for network empowerment ammunition, where the sensors and the controller are connected by a digital communication network with data-rate limitations. Different from the existing ones, a new bit-allocation algorithm on the basis of the singular values of the plant matrix is proposed to encode the plant states. A lower bound on the data rate is presented to ensure stabilization of the unstable plant. It is shown in our results that, the algorithm can be employed for the more general case. An illustrative example is given to demonstrate the effectiveness of the proposed algorithm

Interrogation of Ultra-weak FBG Array using Double-pulse and Heterodyne Detection

A high performance interrogation method for ultra-weak FBG (UWFBG) using double-pulse and heterodyne detection method is proposed. The perturbation along the UWFBG array is located quickly through the use of double-pulsed optical input waveform. Then the perturbation of fiber is quantified precisely by demodulating the phase of differential signals from a heterodyne configuration. The efficiency of measuring the perturbation is improved by more than 20 times than that of using single probe pulse. In comparison with conventional Rayleigh scattering based approach, the proposed method is supreme in signal-to-noise ratio (SNR), approximately 18 dB higher. The use of differential signaling method can effectively remove the influence from frequency drift of the laser source, making this proposed method capable of measuring low frequency vibration. In our experiment, perturbations with both sinusoidal and triangle waveform were generated to quantitatively evaluate the performance of the proposed method. The minimum detectable fiber length variation is 14.85 nm, and the sensing frequency can be as low as 0.2 Hz

Phase sensitive distributed vibration sensing based on ultraweak fiber Bragg grating array using double-pulse

A distributed vibration sensing technique using double-optical-pulse based on phase-sensitive optical time-domain reflectometry (φ-OTDR) and an ultraweak fiber Bragg grating (UWFBG) array is proposed for the first time. The single-mode sensing fiber is integrated with the UWFBG array that has uniform spatial interval and ultraweak reflectivity. The relatively high reflectivity of the UWFBG, compared with the Rayleigh scattering, gains a high signal-to-noise ratio for the signal, which can make the system achieve the maximum detectable frequency limited by the round-trip time of the probe pulse in fiber. A corresponding experimental φ-OTDR system with a 4.5 km sensing fiber integrated with the UWFBG array was setup for the evaluation of the system performance. Distributed vibration sensing is successfully realized with spatial resolution of 50 m. The sensing range of the vibration frequency can cover from 3 Hz to 9 kHz