Optical design and Taguchi optimization of third-order aberrations for contact lenses

The contact lenses was designed by optical design software of CODE V, we found that the spherical aberration, which did not conform the lowest performance. In order to achieve the optimal values of spherical aberration, we employed the Taguchi method to solve an optimization problem.     

Identity authentication by sensed acoustic voices from a speaking person using an efficient GMM-SVM dual modeling framework

Microsystem Technologies - With continuously growing maturity, speaker verification applications using sensed voices from the person to verify his identify and validness have increased in daily...     

Hybridized estimations of support vector machine free parameters C and γ using a fuzzy learning strategy for microphone array-based speaker recognition in a Kinect sensor-deployed environment

The support vector machine (SVM) is a popular classification model for speaker verification. However, although SVM is suitable for classifying speakers, the uncertain values of the free parameters C and γ of the SVM model have been a challenging technique problem. An improper value set provided for the free parameter pair (C, γ) can cause dissatisfactory performance in the recognition accuracy of speaker verification. Moreover, the sound source localization information of the collected acoustic data has a large effect on the recognition performance of SVM speaker verification. In response, this study developed a sound source localization-driven fuzzy scheme to help determine the optimal value set of (C, γ) for the establishment of an SVM model. Specifically, this scheme adopts the estimated information of time difference of arrival (TDOA) derived from the Kinect microphone array (containing both the angle and distance information of the acoustic data of the speaker), to optimally calculate the value set of the SVM free parameters C and γ. It was demonstrated that speaker verification using the SVM with a properly estimated parameter pair (C, γ) is more accurate than that with only an arbitrarily given value set for the parameter pair (C, γ) on recognition rate.

     

Incremental MLLR speaker adaptation by fuzzy logic control

This paper presents a fuzzy control mechanism for conventional maximum likelihood linear regression (MLLR) speaker adaptation, called FLC-MLLR, by which the effect of MLLR adaptation is regulated according to the availability of adaptation data in such a way that the advantage of MLLR adaptation could be fully exploited when the training data are sufficient, or the consequence of poor MLLR adaptation would be restrained otherwise. The robustness of MLLR adaptation against data scarcity is thus ensured. The proposed mechanism is conceptually simple and computationally inexpensive and effective; the experiments in recognition rate show that FLC-MLLR outperforms standard MLLR especially when encountering data insufficiency and performs better than MAPLR at much less computing cost.     

Hybrid analog/digital wavelength-time optical CDMA systems in radio-over-fiber transmissions

This study presents a hybrid analog/digital (A/D) mechanism of two-dimensional (2-D) structure of wavelength-hopping and time-spreading coding optical code-division multiple-access (OCDMA) system for future generation communication and network technologies. The 2-D method increases the maximum permissible number of simultaneous base stations (BSs) and security using a finite bandwidth of optical broad-band light source (BLS). In the proposed system, we can employ low-cost BLS which can mitigate the sampling rate of optical switch (OSW) and has the advantage of power saving. The performance enhancement is using the time-spreading method by a Mach-Zehnder modulator (MZM) with switch function to suppress the phase-induced intensity noise (PIIN) effect of the wavelength domain and the receiver structure is equipped with balanced detectors in order to suppress the multiple-access interference (MAI). In addition, the hybrid OCDMA network is equipped using a dual input MZM for the choice which time analog or digital signals to be transmitted and the advantage of these two kinds of signals can transmit by the same coder/decoder (codec) mechanism and recover by different type filters in the receiver end. The numerical evaluation results demonstrate that, for analog and digital signals under PIIN- and MAI-limited conditions, the proposed system outperforms a conventional multi-wavelength and time-spreading OCDMA scheme. Hence, enhancing the confidentiality of the asynchronous networks of codeword assignments and integratable hardware designs for the scheme with a MZM, an optical switch (OSW), arrayed-waveguide grating (AWG) and fiber Bragg gratings (FBGs) in hybrid A/D 2-D OCDMA system is proposed.