Design and Preparation Method of Fiber Optoacoustic Effect Device Used for Artificial Optical Cochlea

2013 ◽  
Vol 364 ◽  
pp. 453-457 ◽  
Author(s):  
Chen Li ◽  
Jing Xuan Wang ◽  
Lan Tian
Keyword(s):  
Cochlear Implant ◽  
Auditory Perception ◽  
Preparation Method ◽  
Experimental System ◽  
Optical Signal ◽  
Laser Source ◽  
Fiber Array ◽  
Optoacoustic Effect ◽  
The Time Domain ◽  
Selection Of

Laser can stimulate sound wave, its possible for fiber laser to evoke neural activity safely and produce the auditory perception, this acts as the electrode role in cochlear implant. Moreover, the laser is characterized by definite direction and optical signal between adjacent fibers dont readily interfere. Therefore, optical fiber cochlear implant based on optoacoustic effect is promising. The design and preparation of an experimental system based on optoacoustic effect is introduced in this paper. The selection of laser source and the control methods of optical signal were discussed, and testing results of the fiber optoacoustic effect, including the time domain waveforms and spectrograms of the evoked optoacoustic sound were given. Also, a preliminary discussion for the extended fiber array system applied in artificial fiber cochlea as an alternative to electrodes stimulation was progressed.

Laser Stimulation Control System Design of the Auditory Nerve

2014 ◽  
Vol 1046 ◽  
pp. 116-120
Author(s):  
Nan Yang ◽  
Jing Xuan Wang ◽  
Lan Tian ◽  
Yong Wang
Keyword(s):  
Cochlear Implant ◽  
Pulse Energy ◽  
Dynamic Range ◽  
Experimental System ◽  
Optical Signal ◽  
Frequency Resolution ◽  
Energy Regulation ◽  
Optical Stimulation ◽  
Fiber Array ◽  
Stimulation Of

Optical stimulation of the inner ear, the cochlea, has been proved as a possible alternative to conventional cochlear implant with the hypothetical improvement of dynamic range and frequency resolution. Moreover, the laser has good directionality character and optical signal between adjacent fibers do not readily interfere. Therefore, cochlear implant based on optical stimulation is promising for further exploration and development. The design of an experimental system for optical stimulation of the cochlea is introduced in this paper. For the important part, the selection of NIR laser and the optical signal control methods were discussed. The pulsed laser light was coupled by fiber or fiber array and radiated to the cochlea. For each channel laser pulse, the width modulation was varied from 10us to 1ms, the pulse repetition rate from 5 Hz to 10 KHz, single pulse energy from 0 to 3.6mJ. The application of high precision DAC made the resolution of the pulse energy regulation up to 1uJ/div. The experiment results show that this design and implementation can meet the requirements on further optical stimulation of the cochlea research.

The Effect of Vibration Noise for Cavity Ring Down Time Extraction

2013 ◽  
Vol 562-565 ◽  
pp. 1402-1407
Author(s):  
Xiang Ran Meng ◽  
Yu Zhao ◽  
Xiao Qian Wang ◽  
Peng Fei Xu ◽  
Wen Dong Zhang ◽  
...  
Keyword(s):  
Experimental System ◽  
Response Characteristic ◽  
Optical Signal ◽  
Detector Response ◽  
Photoelectric Detector ◽  
Different Response ◽  
Micro Sphere ◽  
Quality Factor Q ◽  
Vibration Noise ◽  
Cavity Ring Down

A continue-wave cavity ring down experimental system is established surrounding the micro-sphere cavity. In the experiments of measuring micro-spheres cavity quality factor (Q) upon the system, it is found that photoelectric detectors with different response characteristic have different response to the optical signal which is shut off rapidly. The vibration noise caused by changes of external environment, meanwhile, can be transformed following the change of photoelectric detector properties. With the build of photoelectric detector response model, the mean-square deviation of repeated experiments under the same conditions is used for charactering level of the error caused by vibration noise. The influence of vibration noise to photoelectric detector is discussed in detail, and further analyzes the effect for the cavity ring down time extraction. Then the optimal photoelectric detector (Newfocus1434, 15V/W) is selected to optimize the experimental system. The level of error caused by vibration noise has been decreased from 0.191ns to 1.562ps. Finally, the Q value of micro-sphere cavity is calculated according to fitted value of cavity ring down time, and the experimental correctness is verified by the line-width law.

Machine Fault Detection Using Genetic Programming

2005 ◽  
Author(s):  
B. Samanta
Keyword(s):  
Fault Detection ◽  
Genetic Programming ◽  
Vibration Data ◽  
Rotating Machine ◽  
Fault Recognition ◽  
Machine Fault ◽  
Artificial Neural Network Ann ◽  
Monitoring And Diagnostics ◽  
The Time Domain ◽  
Selection Of

Applications of genetic programming (GP) include many areas. However applications of GP in the area of machine condition monitoring and diagnostics is very recent and yet to be fully exploited. In this paper, a study is presented to show the performance of machine fault detection using GP. The time domain vibration signals of a rotating machine with normal and defective gears are processed for feature extraction. The extracted features from original and preprocessed signals are used as inputs to GP for two class (normal or fault) recognition. The number of features and the features are automatically selected in GP maximizing the classification success. The results of fault detection are compared with genetic algorithm (GA) based artificial neural network (ANN)- termed here as GA-ANN. The number of hidden nodes in the ANN and the selection of input features are optimized using GAs. Two different normalization schemes for the features have been used. For each trial, the GP and GA-ANN are trained with a subset of the experimental data for known machine conditions. The trained GP and GA-ANN are tested using the remaining set of data. The procedure is illustrated using the experimental vibration data of a gearbox. The results compare the effectiveness of both types of classifiers with GP and GA based selection of features.

Effect of Increased Daily Cochlear Implant Use on Auditory Perception in Adults

2021 ◽  
pp. 1-12
Author(s):  
Jourdan T. Holder ◽  
René H. Gifford
Keyword(s):  
Speech Recognition ◽  
Cochlear Implant ◽  
Auditory Perception ◽  
Underlying Mechanism ◽  
Causal Link ◽  
Data Logging ◽  
Spectral Processing ◽  
Wear Time ◽  
Percentage Points ◽  
Questionnaire Administration

Purpose Despite the recommendation for cochlear implant (CI) processor use during all waking hours, variability in average daily wear time remains high. Previous work has shown that objective wear time is significantly correlated with speech recognition outcomes. We aimed to investigate the causal link between daily wear time and speech recognition outcomes and assess one potential underlying mechanism, spectral processing, driving the causal link. We hypothesized that increased CI use would result in improved speech recognition via improved spectral processing. Method Twenty adult CI recipients completed two study visits. The baseline visit included auditory perception testing (speech recognition and spectral processing measures), questionnaire administration, and documentation of data logging from the CI software. Participants watched an educational video, and they were informed of the compensation schedule. Participants were then asked to increase their daily CI use over a 4-week period during everyday life. Baseline measures were reassessed following the 4-week period. Results Seventeen out of 20 participants increased their daily CI use. On average, participants’ speech recognition improved by 3.0, 2.4, and 7.0 percentage points per hour of increased average daily CI use for consonant–nucleus–consonant words, AzBio sentences, and AzBio sentences in noise, respectively. Questionnaire scores were similar between visits. Spectral processing showed significant improvement and accounted for a small amount of variance in the change in speech recognition values. Conclusions Improved consistency of processor use over a 4-week period yielded significant improvements in speech recognition scores. Though a significant factor, spectral processing is likely not the only mechanism driving improvement in speech recognition; further research is warranted.

Analysis of Brief Tension Loss in TLP Tethers

1988 ◽  
Vol 110 (1) ◽  
pp. 43-47 ◽  
Author(s):  
J. N. Brekke ◽  
T. N. Gardner
Keyword(s):  
Time Domain ◽  
Large Diameter ◽  
Nonlinear Effects ◽  
Response Analysis ◽  
Bending Stress ◽  
Large Wave ◽  
Wave Trough ◽  
Design Selection ◽  
The Time Domain ◽  
Selection Of

The avoidance of “slack” tethers is one of the factors which may establish the required tether pretension in a tension leg platform (TLP) design. Selection of an appropriate safety factor on loss of tension depends on how severe the consequences may be. It is sometimes argued that if tethers go slack, the result may be excessive platform pitch or roll motions, tether buckling, or “snap” or “snatch” loading of the tether. The results reported here show that a four-legged TLP would not be susceptible to larger angular motions until two adjacent legs lose tension simultaneously. Even then, this analysis shows that a brief period of tether tension loss (during the passage of a large wave trough) does not lead to excessive platform motion. Similarly, momentary tension loss does not cause large bending stress in the tether or significant tension amplification as the tether undergoes retensioning. This paper presents TLP platform and tether response analysis results for a representative deepwater Gulf of Mexico TLP with large-diameter, self-buoyant tethers. The time-domain, dynamic computer analysis included nonlinear effects and platform/tether coupling.

Model for Understanding the Influence of Some Parameters in Cochlear Implantation

1992 ◽  
Vol 101 (1) ◽  
pp. 42-45 ◽  
Author(s):  
Christian Berger-Vachon ◽  
Bachir Djedou ◽  
Lionel Collet ◽  
Alain Morgon
Keyword(s):  
Cochlear Implant ◽  
Cochlear Implants ◽  
Cochlear Implantation ◽  
Recognition Performance ◽  
Open Channels ◽  
Major Goal ◽  
Good Selection ◽  
Selection Of

Considering the recognition performance obtained by an implanted patient, the authors have developed models to explain the decrease in performance when the number of open channels on the prosthesis is increased. The French cochlear implant Chorimac was used in this experiment. Two models have been developed. The first is monodimensional and the second is multidimensional. They respectively represent an increase in information and its superposition. Results suggest that for the patient, the superposition factor prevails and is detrimental to recognition. Its elimination should be a major goal. A good selection of electrodes in a relatively small number seems to be the best policy. This is already done in some cochlear implants. Some other parameters in the signal that seem worth being analyzed are introduced.

scholarly journals Coordination chemistry of Ca sites at the surface of nanosized hydroxyapatite: interaction with H 2 O and CO

2012 ◽  
Vol 370 (1963) ◽  
pp. 1313-1336 ◽  
Author(s):  
Vera Bolis ◽  
Claudia Busco ◽  
Gianmario Martra ◽  
Luca Bertinetti ◽  
Yuriy Sakhno ◽  
...  
Keyword(s):  
Preparation Method ◽  
Co Adsorption ◽  
Specimen Preparation ◽  
High Coverage ◽  
Mild Conditions ◽  
Specific Effects ◽  
Vapour Adsorption ◽  
Co Probe ◽  
Ir Spectroscopic ◽  
Selection Of

The affinity towards water of a selection of well-defined, nanostructured hydroxyapatite (HA) samples was investigated by H 2 O vapour adsorption microcalorimetry and infrared (IR) spectroscopy. A large hydrophilicity of all investigated materials was confirmed. The surface features of hydrated HA were investigated on the as-synthesized samples pre-treated in mild conditions at T =303 K, whereas dehydrated HA features were characterized on samples activated at T =573 K. The relatively large hydrophilicity of the hydrated surface (−Δ ads H∼100–50 kJ mol −1 ) was due to the interaction of water with the highly polarized H 2 O molecules strongly coordinated to the surface Ca 2+ cations. At the dehydrated surface, exposing coordinatively unsaturated ( cus ) Ca 2+ cations, H 2 O was still molecularly adsorbed but more strongly (−Δ ads H∼120–90 kJ mol −1 ). The use of CO adsorption to quantify the Lewis acidic strength of HA surface sites revealed only a moderate strength of cus Ca 2+ cations, as confirmed by both microcalorimetric and IR spectroscopic measurements and ab initio calculations. This result implies that the large HA/H 2 O interaction energy is due to the interplay between cus Ca 2+ sites and nearby hydrophilic PO 4 groups, not revealed by the CO probe. The lower density of cus Ca 2+ cations at the 573 K activated HA surface with respect to the pristine one did not affect the whole hydrophilicity of the surface, as the polarizing effect of Ca sites is so strong to extend up to the fourth hydrated layer, as confirmed by both high-coverage microcalorimetric and IR spectroscopic data. No specific effects due to the investigated specimen preparation method and/or different morphology were observed.

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