Data-Driven Distributed Optical Vibration Sensors: A Review

Distributed optical vibration sensors (DOVS) have attracted much attention recently since it can be used to monitor mechanical vibrations or acoustic waves with long reach and high sensitivity. Phase-sensitive optical time domain reflectometry (Φ-OTDR) is one of the most commonly used DOVS schemes. For Φ-OTDR, the whole length of fiber under test (FUT) works as the sensing instrument and continuously generates sensing data during measurement. Researchers have made great efforts to try to extract external intrusions from the redundant data. High signal-to-noise ratio (SNR) is necessary in order to accurately locate and identify external intrusions in Φ-OTDR systems. Improvement in SNR is normally limited by the properties of light source, photodetector and FUT. But this limitation can also be overcome by post-processing of the received optical signals. In this context, detailed methodologies of SNR enhancement post-processing algorithms in Φ-OTDR systems have been described in this paper. Furthermore, after successfully locating the external vibrations, it is also important to identify the types of source of the vibrations. Pattern classification is a powerful tool in recognizing the intrusion types from the vibration signals in practical applications. Recent reports of Φ-OTDR systems employed with pattern classification algorithms are subsequently reviewed and discussed. This thorough review will provide a design pathway for improving the performance of Φ-OTDR while maintaining the cost of the system as no additional hardware is required

An Assay for Systematically Quantifying the Vestibulo-Ocular Reflex to Assess Vestibular Function in Zebrafish Larvae

Zebrafish (Danio rerio) larvae are widely used to study otic functions because they possess all five typical vertebrate senses including hearing and balance. Powerful genetic tools and the transparent body of the embryo and larva also make zebrafish a unique vertebrate model to study otic development. Due to its small larval size and moisture requirement during experiments, accurately acquiring the vestibulo-ocular reflex (VOR) of zebrafish larva is challenging. In this report, a new VOR testing device has been developed for quantifying linear VOR (LVOR) in zebrafish larva, evoked by the head motion about the earth horizontal axis. The system has a newly designed larva-shaped chamber, by which live fish can be steadily held without anesthesia, and the system is more compact and easier to use than its predecessors. To demonstrate the efficacy of the system, the LVORs in wild-type (WT), dlx3b and dlx4b morphant zebrafish larvae were measured and the results showed that LVOR amplitudes were consistent with the morphological changes of otoliths induced by morpholino oligonucleotides (MO). Our study represents an important advance to obtain VOR and predict the vestibular conditions in zebrafish

Imunokromatografsko testiranje lateralnog toka (LFIA) čitača trake temeljeno na rasporedu i 8051 IP jezgri

Lateral flow immunochromatographic assay (LFIA) testing is essential for accurate detection and diagnoses of diseases and physical conditions. However, the existing LFIA strip reader equipped with high cost of hardware confines its simplicity and portability. Therefore, this study develops a simple, low cost LFIA strip reader comprising 4 major modules --- mechanical, optical, processing and control modules. The mechanical module pulls in and out the test strip automatically to be read by the optical module and the data processing module provides the test results by analyzing the data sent by the optical module. All the individual modules are controlled by a control module. To reduce the hardware budget and control complexity, a time-triggered cooperative (TTC) scheduler implemented on an 8051 IP core was chosen as control system. In addition, special, high sensitivity C- reactive protein (CRP) strips with 10 different concentrations were tested to evaluate the performance of the system. Further, a commercial ESEQuant lateral flow reader (QIAGEN, Germany) was tested as a comparative study. The test results show that the proposed reader was stable with a coefficient of variation (CV) factor within 3%. To test the qualitative performance of the system, each of the CRP concentration were examined for 10 times, which indicates that the system has a large dynamic detection range and good detection linearity (^2 = 0.998). In short, the proposed LFIA strip reader has high potential relative to existing readers, especially in simplicity and cost.Imunokromatografsko testiranje lateralnog toka (LFIA) nužno je za preciznu detekciju i dijagnozu oboljenja te psihičkih stanja. Međutim, postojeći LFIA opremljeni s hardverom visoke cijene limitiraju jednostavnost i prenosivost. Ovo istraživanje razvija jednostavni, niske cijene, čitač traka koji se sastoji od 4 glavna dijela - mehanički, optički, procesni i upravljački. Mehanički modul povlači testnu traku automatski kako bi optički modul mogao čitati. Procesni modul analizira podatke dobivene s optičkog čitača. Svaki modula upravlja se upravljačkim modulom. Vremensko ovisno kooperativni raspored implementiran je na 8051 IP jezgri kako bi se smanjili računski zahtjevi. Dodatno, visoko osjetljiva CRP traka s deset različitih koncentracija korištena je u svrhe evaluacije sustava. Rezultati su uspoređeni s komercijalnim čitačem lateralnog toka ESEQuant (QIAGEN, Njemačka). Rezultati pokazuju da je predložena metoda stabilna s koeficijentom varijacije unutar 3%. Kako bi se kvalitativno testirao sustav, svaka od CRP koncentracija testirana je deset puta, što ukazuje da sustav veliki dinamički raspon detekcije te dobru linearnost detekcije (R^2 = 0.998). Predloženi LFIA čitač traka ima dosta potencijala u usporedbi s postoječim čitačima, posebno u smislu jednostavnosti i cijene

Wavelet analysis and applications

Reflects the developments in the area of wavelet analysis and its applications. This work includes topics such as: Approximation and Fourier Analysis; Construction of Wavelets and Frame Theory; Fractal and Multifractal Theory; Wavelets in Numerical Analysis; Time-Frequency Analysis; and Applications, particularly in image processing

Liquid Crystal-Embedded Hollow Core Fiber Temperature Sensor in Fiber Ring Laser

An optical fiber temperature sensor based on Mach–Zehnder interferometer and thermo-optic effect of the liquid crystal (LC) in fiber ring laser (FRL) system is proposed and experimentally demonstrated. The LC is infiltrated into the core of hollow core fiber, and the resonant wavelength is more sensitive to temperature variation due to the interaction between the incident light and the cavity infiltrating liquid crystal with high thermal light coefficient. Meanwhile, the FRL system was further used to make the sensor have good performance in the case of high signal-to-noise ratio (∼35 dB), narrow half-height width (FWHM = 0.15 nm), and high sensitivity in the temperature range from 20 °C to 50 °C, with the maximum sensitivity of 1.318 nm/°C. As far as we know, in the FRL system, the liquid crystal material has a better temperature sensing performance than the previous fiber. Nevertheless, the system has the advantages of good repeatability, low cost, simple production, small volume, high sensitivity. In marine microbial culture and detection, it is necessary to carry out high sensitivity measurement within a small temperature variation range. This reliable and excellent temperature performance has a potential application prospect

Resting and Initial Beta Amplitudes Predict Learning Ability in Beta/Theta Ratio Neurofeedback Training in Healthy Young Adults

Neurofeedback (NF) training has been proved beneficial in cognitive and behavioral performance improvement in healthy individuals. Unfortunately, the NF learning ability shows large individual difference and in a number of NF studies there are even some non-learners who cannot successfully self-regulate their brain activity by NF. This study aimed to find out the neurophysiological predictor of the learning ability in up-regulating beta-1 (15-18 Hz) / theta (4-7 Hz) ratio (BTR) training in healthy young adults. Eighteen volunteers finished five training sessions in successive five days. We found that low beta (12-15 Hz) amplitude in a 1-min eyes-open resting baseline measured before training and the beta-1 amplitude in the first training block with 4.5-min duration could predict the BTR learning ability across sessions. The results provide a low cost, convenient and easy way to predict the learning ability in up-regulating BTR training, and would be helpful in avoiding potential frustration and adjusting training protocol for the participants with poor learning ability

Fiber Temperature Sensor Based on Vernier Effect and Optical Time Stretching Method

A novel method for ultra-sensitive and ultra-fast temperature sensing has been successfully implemented by cascading Saganc rings to generate the Vernier effect and doing the same dispersive fibers to achieve the optical time-stretching effect. This is different from the traditional point fiber sensor demodulated by optical spectrum analyzer (OSA) whose demodulation speed is usually at the second level. The designed system maps the wavelength domain to the time domain through the dispersive fiber, which can realize the ultra-fast temperature monitoring at the nanosecond level. The cascaded Sagnac ring is composed of polarization maintaining fiber (PMF) which is significantly affected by the thermal-optical coefficient. When the temperature changes, the variation is as high as −6.228 nm/°C, which is 8.5 times higher than the sensitivity based on the single Sagnac ring system. Furthermore, through the optical time stretching scheme, the corresponding response sensitivity is increased from 0.997 ns/°C to 7.333 ns/°C, and the magnification is increased 7.4 times with a response speed of 50 MHz

A Unified Knowledge Extraction Method Based on BERT and Handshaking Tagging Scheme

In the actual knowledge extraction system, different applications have different entity classes and relationship schema, so the generalization and migration ability of knowledge extraction are very important. By training a knowledge extraction model in the source domain and applying the model to an arbitrary target domain directly, open domain knowledge extraction technology becomes crucial to mitigate the generalization and migration ability issues. Traditional knowledge extraction models cannot be directly transferred to new domains and also cannot extract undefined relation types. In order to deal with the above issues, in this paper, we proposed an end-to-end Chinese open-domain knowledge extraction model, TPORE (Extract Open-domain Relations through Token Pair linking), which combined BERT with a handshaking tagging scheme. TPORE can alleviate the nested entities and nested relations issues. Additionally, a new loss function that conducts a pairwise comparison of target category score and non-target category score to automatically balance the weight was adopted, and the experiment results indicate that the loss function can bring speed and performance improvements. The extensive experiments demonstrate that the proposed method can significantly surpass strong baselines. Specifically, our approach can achieve new state-of-the-art Chinese open Relation Extraction (ORE) benchmarks (COER and SAOKE). In the COER dataset, F1 increased from 66.36% to 79.63%, and in the SpanSAOKE dataset, F1 increased from 46.0% to 54.91%. In the medical domain, our method can obtain close performance compared with the SOTA method in the CMeIE and CMeEE datasets