InDEX: Indonesian Idiom and Expression Dataset for Cloze Test

We propose InDEX, an Indonesian Idiom and Expression dataset for cloze test. The dataset contains 10438 unique sentences for 289 idioms and expressions for which we generate 15 different types of distractors, resulting in a large cloze-style corpus. Many baseline models of cloze test reading comprehension apply BERT with random initialization to learn embedding representation. But idioms and fixed expressions are different such that the literal meaning of the phrases may or may not be consistent with their contextual meaning. Therefore, we explore different ways to combine static and contextual representations for a stronger baseline model. Experimentations show that combining definition and random initialization will better support cloze test model performance for idioms whether independently or mixed with fixed expressions. While for fixed expressions with no special meaning, static embedding with random initialization is sufficient for cloze test model.Comment: Accepted to "2022 International Conference on Asian Language Processing (IALP)

Retinal Ganglion Cell Responses to Low-frequency Focused Ultrasound Stimulation

PURPOSE: Acoustic retinal prosthesis has been put forward using high-frequency US with non-invasive and high-resolution advantages. But its application is limited by the difficulties in fabrication, energy consumption and acoustic attenuation. In the present study, low-frequency focused ultrasound stimulation (LFUS) had been demonstrated to activate retinal ganglion cells (RGCs) in rat retinas. The neurophysiological properties of RGC responses to LFUS were also investigated. METHODS: A 2.25 MHz focused ultrasound transducer (D=0.75 in., SF=2.0 in.) was used to stimulate the rat retina which was cultured in a multi-electrode array system (MEA2100, MCS , Fig. 1). The acoustic property was evaluated by hydrophone (UMS3, Precision acoustics). Ultrasound (US) stimulation was modulated at pulsed mode. Light stimulation was modulated in the same mode to give an uniform field flashes. The electrophysiological data collected from MEA was detected for neural spikes and sorted by Plexon Offline Sorter. Only channels recording single-cell activities were adopted for subsequent analysis. Peri-stimulus time histograms and raster plots were plotted for each RGC using Spike 2. RESULTS: In total, 116 retinal ganglion cells (RGCs) from 7 retinas were sorted and classified into four types according to light responses. The firing activity of 114 RGCs were modulated by repeated US stimulation. This suggested that low-frequency focused ultrasound stimulation (LFUS) could activate RGCs. The US responses didn&rsquo;t correspond to the standard light responses and varied greatly between cell types. Besides, dual-peak responses to US stimulation were observed which were not reported previously. The temporal response properties of RGCs, including latency, firing rate, and response type, could be modulated by changing acoustic intensity. CONCLUSIONS: These findings might imply a temporal neuromodulation effect of LFUS and provided an important foundation for the development of acoustic retinal prosthesis.</p

Adaptive Sliding Mode Trajectory Tracking Control for Unmanned Surface Vehicle with Modeling Uncertainties and Input Saturation

In the presence of modeling uncertainties and input saturation, this paper proposes a practical adaptive sliding mode control scheme for an underactuated unmanned surface vehicle (USV) using neural network, auxiliary dynamic system, sliding mode control and backstepping technique. First, the radial basis function neural network with minimum learning parameter method (MLP) is constructed to online approximate the uncertain system dynamics, which uses single parameter instead of all weights online learning, leading to a reduction in the computational burdens. Then a hyperbolic tangent function is adopted to reduce the chattering phenomenon due to the sliding mode surface. Meanwhile, the auxiliary dynamic system and the adaptive technology are employed to handle input saturation and unknown disturbances, respectively. In addition, a neural shunting model is introduced to eliminate the &#8220;explosion of complexity&#8222; problem caused by the backstepping method for virtual control derivation. The stability of the closed-loop system is guaranteed by the Lyapunov stability theory. Finally, simulations are provided to validate the effectiveness of the proposed control scheme

Retina stimulation with low-frequency ultrasound in vivo

PURPOSE: More and more researches are exploring the neuromodulation effect of ultrasound (US) on the central nervous system (e.g. brain and retina) and the peripheral nervous system (such as skin). US stimulation has been regarded as a new noninvasive neurostimulation approach by many researchers. Our previous studies had shown that the temporal response patterns of RGCs could be modulated by US in vitro. In this article, we studied US stimulation to the retina in vivo. This study attempted to use low-frequency (2.25 MHz) focused US to stimulate the rat eyes and investigate the effect on the primary visual cortex. METHODS: Experiments were conducted on adult male and female Sprague Dawley rats (250&ndash;300 g). A 2.25 MHz focused US transducer (D = 0.75 in., SF = 2.0 in., Olympus, Waltham, MA, USA) was used to stimulate the rat eyes in vivo. Rats were anaesthetized with urethane (5 ml/kg, 20% aqueous solution, intraperitoneally; Sigma-Aldrich, Munich, Germany). Next, the rat was laid prone on an automatic heating pad (69002, RWD Life Science Co.) at 37℃ and with its head gently immobilized using a stereotaxic frame (68028, RWD Life Science Co.). The skin on the head was swabbed with iodine and then a local anesthetic (lidocaine hydrochloride, Lidocaine 0.5%, 1mL) was injected subcutaneously along the incision line. The skull was exposed and trephined in an area (4x4 mm2) overlaying the monocular visual cortex: 6.0 mm posterior to bregma, and 3.0 mm lateral from the midline, the depth of multi-electrode arrays implantation were 300-500&micro;m below the pia surface. US stimulation was modulated in the pulsed mode, which parameters included: pulse repetition frequency (PRF) = 1 kHz, tone burst duration (TBD) = 0.5 ms, sonication duration (SD) = 300 ms, and inter-stimulus interval (ISI) = 3 s. In each experiment, 40 trials (stimulus trains) were delivered, and there were 2-min intervals between each experiment. The neural activities from the primary visual cortex was amplified, filtered and digitized by Cerebus 64-Channel system (Animal Use). RESULTS: As shown in Fig. 1a, the low-frequency focused US (2.25 MHz) transducer was used to stimulate the rat left eye and a 4x4 multi-electrode array was used to record neural activities from the right primary visual cortex. Some preliminary experimental results showed that the local field potentials and the single neuron spikes recorded from the primary visual cortex were both changed by US stimulation. Fig. 1b showed the responses of local field potentials that were recorded by 13 electrodes to US stimulation. The average latency of these responses was about 250 ms, which was consistent with the previous study. The peri-stimulus time histogram (PSTH) of a single spiking unit that was sorted by Offline Sorter showed that the neuron responded to US stimulation at the offset Fig. 1c. CONCLUSIONS: Such influence on the neural activities in brain demonstrated that the low-frequency focused US was capable of stimulating retinas in vivo, which might become a novel therapy tool for ophthalmic diseases. Figure 1. US influenced on the neural activities of visual cortex. (a) The experimental paradigm. US stimulation to the rat left eye and multi-electrode arrays recording from the right primary visual cortex. (b) The local field potentials responded to US stimulation. X-axis is time (ms) and Y-axis is recording channels. (c) The PSTH of a single spiking unit that was sorted by Offline Sorter. X-axis is time (ms) and Y-axis is firing rate (Hz) .</p

Method for Determining the Valid Travel Route of Railways Based on Generalised Cost under the Syncretic Railway Network

Travel route options for passengers can provide data support for railway line planning, passenger flow organisation, and train operation establishment. A critical review of the literature indicates that previous studies mainly focused on choices offered by a single railway network path without much consideration of China’s normal-speed and high-speed integrated railway network and the effect of train timetable on passengers’ travel choice. In this study, a method based on generalised cost is proposed to discover the valid routes of passenger travel in the integrated network of China’s normal-speed and high-speed railways. After quantifying the effects of train fare, travel time, transfer, travel convenience, comfort, and other factors on the generalised expenses of passengers, this study presents a generalised cost determination method when individuals select an option from different seats of different trains of specific railway transport products. Theoretically, the valid routes considering the train schedule is defined, and a valid route search algorithm is designed using the deep traversal idea in a new valid route searching network. Considering the Lanzhou-Beijing passenger travel routes as an example, this study verifies the practicability of the generalised cost calculation method, as well as that of the valid routes search method

Modeling and Identification for Vector Propulsion of an Unmanned Surface Vehicle: Three Degrees of Freedom Model and Response Model

This paper presents a complete scheme for research on the three degrees of freedom model and response model of the vector propulsion of an unmanned surface vehicle. The object of this paper is &ldquo;Lanxin&rdquo;, an unmanned surface vehicle (7.02 m &times; 2.6 m), which is equipped with a single vector propulsion device. First, the &ldquo;Lanxin&rdquo; unmanned surface vehicle and the related field experiments (turning test and zig-zag test) are introduced and experimental data are collected through various sensors. Then, the thrust of the vector thruster is estimated by the empirical formula method. Third, using the hypothesis and simplification, the three degrees of freedom model and the response model of USV are deduced and established, respectively. Fourth, the parameters of the models (three degrees of freedom model, response model and thruster servo model) are obtained by system identification, and we compare the simulated turning test and zig-zag test with the actual data to verify the accuracy of the identification results. Finally, the biggest advantage of this paper is that it combines theory with practice. Based on identified response model, simulation and practical course keeping experiments are carried out to further verify feasibility and correctness of modeling and identification

Collision Avoidance Using Finite Control Set Model Predictive Control for Unmanned Surface Vehicle

In recent years, with the development of unmanned platforms, unmanned surface vehicles (USV) are attracting more and more attention. Compared to ordinary ships, USV have a smaller volume and faster speed, so their collision avoidance system (CAS) should have better responsiveness and stability. The paper describes a method that is based on finite control set model predictive control (FCS-MPC). A finite control set is generated by more practical control commands: the thruster speed and propulsion angle of the USV. The method is conceptually and computationally simple and yet quite versatile, as it can account for the dynamics of the USV, steering and propulsion system. Based on the theory of FCS-MPC, a safe and fast CAS is proposed, and it is verified in different static and dynamic environments. The real environment model for collision avoidance is established by extracting the environment data from the electronic chart. The result shows that the method is effective and can control the USV to sail safely and quickly in complex real scenarios with multiple dynamic obstacles

Adaptive LOS Path Following for a Podded Propulsion Unmanned Surface Vehicle with Uncertainty of Model and Actuator Saturation

This paper addresses three related issues concerning the path following control of a podded propulsion unmanned surface vehicle (USV), namely modeling, guidance and control. The pod is different from the general propeller-rudder propulsion device, and its essence is a vector thruster. Therefore, first, through various assumptions and simplification, the three-degree of freedom (DOFs) planar motion model of the podded propulsion USV is established. Then, the classical line-of-sight (LOS) guidance strategy is improved by adaptive sideslip angle and a time-varying lookahead distance. Based on the guidance system, the corresponding controllers for yaw rate and surge speed are presented, which are combined by backstepping technology, the neural network minimum parameter learning method and the neural shunting model. Specifically, the neural network minimum parameter learning method is proposed to compensate the uncertainty of the model and the immeasurability of external disturbances, and the neural shunting model is employed to cope with the “explosion of complexity” problem of backstepping. Meanwhile, an auxiliary dynamic system is introduced to prevent actuator saturation (input saturation). All error signals of the system are proven to be uniformly ultimately bounded (UUB) by employing Lyapunov stability theory. Finally, two numerical simulations are given to prove the correctness of the proposed scheme