dataesr/scientific-paragraphs-categorization huggingface dataset:
FEM and experimental validation This section is dedicated to utilizing the FEM software package ANSYS, as a digital tool to numerically replicate mechanical behaviors of the scale model of scooter deck with various designed core structures under threepoint bending tests. Initially, the developed parts of the scale model deck, containing the top shell and merged bottom shell with the core, are transferred to ANSYS. It is noteworthy to mention that the linear elastic behavior and Young's modulus of the PLA material are inputted into ANSYS according to the tensile test results, shown in Fig. 4c. A proper mesh generation as a critical part of the work is taken into consideration since the meshing elements must successfully cover the geometry thoroughly with good precision. In this regard, tetragonal elements are selected.
Mechanical behavior of the scale model of scooter deck with different core patterns As mentioned earlier, the scale model of scooter decks designed with the core structures are subjected to a three-point bending test and simulated via the geometrically non-linear FEM software package ANSYS. Based on the loading nose, a constant displacement of 4 mm in the z-direction is applied, and the reaction force for each designed scale model of deck is determined. Figure  18  depicts a comparison of reaction force-displacement curves from the developed core designs. From the information provided in the figure, it is seen that all core designs result in a similar force-deflection response in the small deformation range (less than 0. 1 mm). However, as the force/displacement increases, the difference in response of different designs becomes obvious.
Conclusion In this paper, different bio-inspired and architected metamaterial core structures were introduced and applied to a scale model of scooter deck under a three-point bending test. A scale sample of deck with a honeycomb core was initially developed and fabricated from PLA via the FFF 3D printing technique. Its bending behavior was then investigated experimentally under the three-point bending condition. Following that, the experiment was simulated by implementing a geometrically non-linear FEM. A comparison study showed that the results of the FEM model agree well with the experimental data in small and large deformation regimes. After this validation, the bending resistance was numerically evaluated by applying various designs inspired by natural patterns and shapes to the deck's core, such as re-entrant, tetrachiral, starshaped, arrowhead, and graded arrowhead structures.
The receiver is implemented using the Software-Defined Radio (SDR) paradigm and is able to extract the audio signal (corresponding to the usual FM transmission) and the data component, depending on the geographical area in which the vehicle is located. The receiver is based on a novel implementation of a modified Costas loop using two new nonlinear limiters. Appropriate image notification is selected using a specific decoding key, generated according to the geographical position of the vehicle. The performance of the data transmission system is analyzed by plotting the Bit Error Rate (BER) versus the signal-to-noise ratio of the data signal for different numbers of image notifications simultaneously transmitted. The proposed radio communication system was validated through an experimental setup based on Universal Software Radio Peripheral (USRP) devices driven by MATLAB/Simulink software.
Several implementations of DSSS modulation using the SDR paradigm have been reported in literature. For example, in  [19] , the authors described a DSSS implementation on a GNU Radio Companion dedicated to satellite communications. In  [20] , the authors reported an implementation for the USRP of a software-defined radio transceiver based on DSSS. The spreading sequence is a chaotic signal whit the same properties as a pseudo-random noise (PN) signal, which is classically employed in commercial communications. The rest of the paper is organized as follows. Section II presents the description of the proposed drivers' warning application through personalized data transmission. This section also presents the implementation of the SDR communication system employed for data transmission by using DSSS-CDMA modulation on typical FM radio broadcasting.
Section III presents the simulation results performed in MATLAB/Simulink and those experimentally obtained for the proposed radio communication system. In Section IV, the conclusions of this paper are drawn. In this paper, a new application for drivers' warning through personalized image notifications simultaneously transmitted in different geographic areas is presented. As shown in Fig. 1 , the proposed application can simultaneously transmit a number of n different images in n distinct geographical areas using the existing FM radio infrastructure. In this way, each driver is warned only about traffic events that are specific to the area in which they drive the car. The maximum number of images that can be transmitted simultaneously depends on the capacity of the radio communication channel in the subsidiary FM bands, as well as the signal-to-noise ratio of data transmission.
The customized baseband signal used for a professional radio transmitter includes the multiplex (MPX) stereo component (used for standard FM radio broadcasting) and a set of data images, which are included in a DSSS-CDMA spectrum component that modulates a 76 kHz subcarrier. The spectrum of the composite signal containing the standard MPX component, together with the data components, is illustrated in Fig. 4. To generalize the problem of image transmission in the FM subsidiary band, the case of n simultaneously transmitted images is considered. However, for practical implementation, n is considered to be equal to 15. The car's radio receiver is implemented using a softwaredefined radio technique and is used to receive warning image notifications, according to the geographical position of the car, together with the standard FM transmission.
B. PROPOSED ARCHITECTURE OF THE FM RADIO TRANSMITTER EMPLOYED FOR FM BROADCATING AND DATA TRANSMISSION In Fig. 5 , the block diagram of the radio transmitter, including the MPX stereo signal and DSSS-CDMA data generators, is illustrated. This customized baseband signal is softwaregenerated using MATLAB/Simulink and is applied to an FM modulator, resulting in a signal with a bandwidth of 200 kHz. This signal is broadcasted by a national FM radio station. The RF signal is received by software-defined FM radio receivers installed in vehicles located in distinct geographical areas of the country. A certain image is selected using a decoding key specific to the geographical area in which the vehicle is located. This decoding key is generated according to the geographical coordinates of the vehicle position provided by the GPS system or a mobile phone service.
The value of the chip rate is limited by the available bandwidth of the communication channel in the subsidiary FM bands, which is between 53 and 99 kHz. Thus, n different pseudo-random orthogonal sequences are cyclically shifted. The symbol rate (f s ) used in the proposed system is chosen such that the chip rate is an integer multiple of the input symbol rate according to the following relation: f ch = (n + 1) • f s (2) where SF = n + 1 represents the spreading factor of the proposed DSSS-CDMA transmission. According to (2), the number of images transmitted simultaneously (which represents the length of the PN code) is given by n = (f ch /f s ) -1 (3) Table  1  lists the number of images that can be transmitted simultaneously for different values of input data rate. The value of the symbol rate (f s ) used in the proposed application was chosen to be identical to the data rate of the RBDS signal from standard FM transmissions, which is equal to 1187.
5 bit/s. Thus, the input data rate of each image used in the proposed radio communication system is f b = 2375 bit/s, which allows simultaneous transmission of n = 15 images. Thus, the maximum data rate provided by the proposed system for all 15 images transmitted simultaneously is 35. 625 kbit/s. In the design of the system, a trade-off must be made between the data rate and the BER of the data signal with DSSS-CDMA modulation because the transmission of a larger amount of data causes a significant increase in the noise on the communication channel due to a larger number of users (simultaneously transmitted images), thus increasing the BER. Therefore, a number of more than 31 images transmitted simultaneously is not convenient for the proposed application, due to a very low data rate of each transmitted image and the significant decrease of the signalto-noise ratio (SNR).
C. IMPLEMENTATION OF THE DEDICATED SOFTWARE DEFINED RADIO RECEIVER The most sensitive part of a DSSS system is the synchronization of the PN sequence of the transmitter with that generated at the receiver stage. Synchronization can be implemented using a known preamble between the transmitter and receiver, which is synchronized by a matched filter  [36] ,  [37]. In the literature, this method is known as Data-Aided (DA) synchronization  [38]. In order to perform synchronization, several other techniques, such as single dwell serial search (SDSS), multiple dwell serial search, and matched filter correlations have also been presented. In this paper, a synchronization technique based on SDSS was employed to despread the DSSS-CDMA signal. In Fig. 8 , the block diagram of the Simulink-based FM radio receiver, including the audio stereo signal decoder and DSSS-CDMA demodulator, is presented.
In the following, the simulation results for the case when 15 images are transmitted simultaneously and for a signal-tonoise ratio of the DSSS-CDMA data onto a 76 kHz subcarrier (SNR CDMA ) equal to 22 dB are presented. In Fig. 16 , the following frequency spectra are illustrated: the spectrum of the transmitted baseband FM signal (Fig. 16 (a) ); the spectrum of the transmitted and received customized baseband signal, which includes the stereo MPX component and the DSSS-CDMA data onto a subcarrier of 76 kHz (Figs. 16 (b ) and (c), respectively); the spectrum of the received stereo MPX component obtained at the output of the LPF in Fig. 8  is presented in Fig. 16 (d) ; the spectrum of the received DSSS-CDMA data onto a 76 kHz subcarrier obtained at the output of the BPF in Fig. 8  is presented in Fig.
16 (e) ; the spectrum of the received audio stereo signal is shown in Fig. 16 (f ). As presented in Figs. 16 (b ) and (c), the spectrum of the transmitted and received customized baseband signal include the spectrum of the MPX signal, corresponding to standard FM transmission (between DC -53 kHz), and the spectrum of the DSSS-CDMA data onto a 76 kHz subcarrier, which occupies a frequency bandwidth of 38 kHz in a range between 53 and 99 kHz. Considering the trade-off between the date rate and BER required for optimal image transmission, using the DSSS-CDMA technique, it is possible to transmit a maximum of 15 images in a frequency bandwidth between 53 and 99 kHz at the same time with the standard FM broadcasting. For the same radio communication scenario, in Fig. 17 , the following constellations (scaled for a = 1) are presented: the constellation of the DSSS-CDMA signal corresponding to one transmitted image (Fig.
17      In Fig. 18 , we present some received images for the scenario when all set of 15 images are simultaneously transmitted for different values for the signal-to-noise ratio of the DSSS-CDMA data onto a 76 kHz subcarrier. In order to test the performance of the DSSS-CDMA communication system, regarding its capability to simultaneously transmit as accurately as possible different number of images, the BER value depending on signal-to-noise ratio of the data signal is calculated. To increase the accuracy of the BER estimation, the DLL-based demodulator circuit was disabled and the clock signal used for the local generation of the PN sequence was extracted from the pilot tone of the received MPX stereo signal. Under ideal conditions (considering an AWGN communication channel), this is possible because the chip frequency of the CDMA signal is chosen to be equal to 19 kHz, which is the frequency of the pilot tone.
In Fig. 19 , the BER depending on the signal-to-noise ratio of the received multi-level CDMA signals onto a 76 kHz subcarrier for different numbers of images transmitted simultaneously is presented. The BER vs. SNR curves illustrated in Fig. 19  were drawn by calculating the SNR value obtained from the simulation using the software spectrum analyzer (set to display a two-sided spectrum) from the MATLAB/Simulink program. The BER plots were obtained considering 100660 bits transmitted on the communication channel, representing an image with a resolution of 100 × 100 pixels. The BER accuracy depends on the number of bits transmitted, and for our simulations, it was limited to 9. 934 • 10 -6 (1/100660). Due to the spectral spreading of the DSSS-CDMA signal, its signal-to-noise ratio can be written as SNR CDMA | dB = SNR I | dB -10 log SF ( 38 ) where SF = 16 is the spreading factor of the DSSS-CDMA sequence and SNR I is the signal-to-noise ratio of the nonspread input signal.
2 GHz  [43]. In order to perform the simulations in MATLAB/Simulink by using USRP N210 devices, the Communications System Toolbox Support Package for USRP Radio has been installed. The two USRP N210 use a monopole-type telescopic antenna, with a frequency range between 25 Hz and 1900 MHz and a length in the range of 70 -340 mm. The customized baseband signal, used by the USRP device configured as a transmitter, is generated based on the circuit illustrated in Fig. 5. The second USRP device, configured as a receiver, provides the received baseband FM signal to the software program (MATLAB/Simulink), which is demodulated with the software-defined radio receiver illustrated in Fig. 8. The proposed radio communication system was tested for different operating scenarios, in which 1, 3, 5, 9, 11, and 15 images were transmitted simultaneously.
All transmissions were performed under identical conditions, using the same transmission power level for the RF signal. The RF frequency was set at 109 MHz. The spectrum of the received customized baseband signal is illustrated in Fig. 24. This signal includes the stereo MPX signal and the DSSS-CDMA data onto a 76 kHz subcarrier for the scenario in which all 15 images are transmitted simultaneously. In Table  4  the experimental results are presented. The signal-to-noise ratio of the received multi-level DSSS-CDMA signal was measured using a software spectrum analyzer from MATLAB/Simulink. For the case in which all 15 images are transmitted simultaneously, the signal-to-noise ratio of the received multilevel DSSS-CDMA signal onto a 76 kHz subcarrier that was measured was approximately 21. 88 dB and the number of error bits was 12 from a total of 100660 transmitted bits (BER = 11.
92 • 10 -5 ). For cases in which up to five images were transmitted, there were no error bits. These measurements agree with the results obtained by simulations, as illustrated in Fig. 19 , and are confirmed by the theoretical results. Despite the signal-to-noise ratio variations illustrated in Table  4 , due to imperfections in the propagation channel under laboratory conditions, the obtained values ensure the optimal transmission of all sets of images. Depending on the communication channel noise, to provide the required SNR for the data signal, it may be necessary to increase the power level of the DSSS-CDMA signal spectrum onto a 76 kHz subcarrier with the impairment of the other spectral components. In extreme situations, to avoid exceeding the total modulation level allowed in standard FM transmissions (105.
IV. CONCLUSION In this paper, a new drivers' warning application for different traffic events using personalized pictograms included in radio FM broadcasting have been presented. The proposed application is based on a radio communication system capable of simultaneously transmitting a maximum of 15 images representing different warning messages sent by road authorities for drivers located in different geographical areas together with the standard FM signal. Each warning pictogram is transmitted with a data rate of 2375 bit/s, but the proposed system is able to provide a maximum data rate of 35. 625 kbit/s when all 15 images are transmitted simultaneously using the DSSS-CDMA modulation technique. The system is implemented using software-defined radio technology, and as a result, it is relatively cheap, flexible, and easy to use by drivers, and is based on existing and widespread radio FM infrastructure.
The proposed application uses a novel implementation of a software-defined radio receiver, which can be easily installed on a car tablet, being able to receive the data notification together with the standard FM radio transmission. To receive the data signal, the proposed radio receiver uses a modified Costas-type synchronization loop on the 76 kHz subcarrier, as well as a DLL-based circuit to ensure time synchronization between the PN sequence of the transmitter with that generated at the receiver stage. The proposed radio communication system was tested by simulations performed in MATLAB/Simulink, as well as in laboratory conditions, using an experimental setup that included two USRP-type devices configured as a transmitter and a receiver. According to the simulation results, confirmed by the experimental tests, for the maximum quality reception of each image (BER ≤ 1.
987 • 10 -5 ) from a set of 15 images transmitted simultaneously, the proposed system must ensure a signal-to-noise ratio of the received multi-level CDMA signals higher than 22 dB. This means that the signal-tonoise ratio is higher than 32 dB for each received DEQPSK image. Unlike other driver warning systems, the proposed radio communication system uses the DSSS-CDMA technique, which allows a significant increase in the amount of data transmitted over the FM radio and increases the robustness of the data signal to natural interference, noise, and jamming. In future work, the influence of multipath propagation and mobility aspects impacting the proposed radio communication system will be studied.
DFT calculations Energetic and structural characteristics of GaN/AlN superlattices were investigated via DFT calculations with the Quantum Espresso ab-initio package  [34, 35, 36]  and the thermo_pw driver of routines [37] computing ab-initio material properties. The density functional of Wu et al. [38]  was implemented using wc Projector Augmented Wave (PAW) pseudopotentials with non-linear core corrections  [39]. This functional was chosen since, thereby, the lattice constants and the elastic moduli of the constitutive single crystalline compounds are realistically reproduced. The calculations used the Broyden-Fletcher-Goldfarb-Shanno (BFGS) minimization algorithm  [40]  with cutoffs set respectively at Ec=140 Ry for the kinetic energy of plane waves and rc=1260 Ry for the charge density.
For the reference purpose, total and projected densities of states, henceforth referred to as DOS and PDOS respectively, were calculated for the single crystalline compounds by including the Hubbard correction for strongly correlated systems implemented in the Quantum Espresso package (DFT+U)  [41, 42, 43]. The values of calculated bandgaps (AlN:6. 11 eV, GaN: 3. 50) fit the experimental data (AlN:6. 10 eV, GaN: 3. 45 eV). Figure  3  is the HRTEM image of a 4c-thick GaN QW embedded in 8c-thick AlN adjacent barriers viewed along the [12 ̅ 10] zone axis. The stacking sequence of wurtzite is 'AaBb' where 'A, B', 'a, b' mark metal and nitrogen atoms respectively. This image vizualizes (0002) lattice planes of the wurtzite crystal structure. Fourier filtering, using the 101 ̅ 0 spatial frequency in a series of HRTEM images from several interfacial areas shows the absence of misfit dislocations, further strengthening the conclusion that GaN has grown pseudomorphically, as is shown in the inset of Figure  3.
It corresponds to states defined by the pseudomorphic relationship between the two compounds in mechanical equilibrium (vanishing external stresses). The path toward the minimal elastic energy condition consisted in simultaneously optimizing lattice constants and the elastic energy content of the sample by defining the following objective function and numerically localizing its lowest value (multi-dimensional minimization package MERLIN  [45] ): 𝑓 = ( 𝑐 𝑝𝑟𝑒𝑑 𝐴𝑙𝑁 𝑐 𝑇𝐸𝑀 𝐴𝑙𝑁 -1) 2 + ( 𝑎 𝑝𝑟𝑒𝑑 𝐴𝑙𝑁 𝑎 𝑇𝐸𝑀 𝐴𝑙𝑁 -1) 2 + 𝑤 𝑒𝑙 {𝐸 𝑝𝑟𝑒𝑑 𝑒𝑙,𝐴𝑙𝑁 𝑉 𝑝𝑟𝑒𝑑 𝐴𝑙𝑁 + 𝐸 𝑝𝑟𝑒𝑑 𝑒𝑙,𝐺𝑎𝑁 𝑉 𝑝𝑟𝑒𝑑 𝐺𝑎𝑁 } (1) Indexes 'pred' and 'TEM' mark respectively, quantities predicted and extracted from the TEM micrographs and 𝑉 𝑝𝑟𝑒𝑑 𝐴𝑙𝑁 , 𝑉 𝑝𝑟𝑒𝑑 𝐺𝑎𝑁 are predicted volumes of the respective lattice cells at the mechanical equilibrium. The minimization algorithms included in the MERLIN package tentatively choose values of the function variables until the procedure repeatedly fails to further decrease the current value of f.
Owing to their large size, giant vesicles are regularly imaged at high spatial and temporal resolution by fluorescence microscopy techniques. Dynamical behaviors, such as biochemical pattern formation, membrane fluctuations, and morphological changes can be visualized in real time at the single vesicle level. However, fluorescence imaging generally suffers from a low screening capability, and it remains challenging to convert single-liposome properties into a large data set that enables extraction of rare phenotypes in a quantitative and statistically relevant manner. 13  On the other hand, flow cytometry is a powerful technology for high-throughput screening of giant vesicles. 13, 14  Individual liposomes (or aggregates) diluted in suspension are sequentially analyzed based on scattered light and fluorescence intensity signals.
20  To our knowledge, IFC has been applied to giant vesicle suspensions in only one study that focused on the optimization protocol of liposome production with water-in-oil emulsion transfer methods. 21  In this work, we leverage the commercial IFC instrument ImageStream (Luminex Corporation) to characterize synthetic cell modules from liposome populations (Figure  1A, B ). ImageStream is a benchtop imaging flow cytometer that enables multispectral acquisition of individual cells or objects in flow. We develop a comprehensive pipeline for liposome identification, selection of unilamellar vesicles, and multimodal analysis of image-based phenotypes using the built-in image processing software IDEAS. We finally discuss the current limitations and opportunities of IFC as an enabling technology to accelerate synthetic cell research.
Therefore, the first step in the overall analysis pipeline consisted in setting up a gating strategy for selecting solely giant liposomes and excluding any other objects. At every step of the analysis, visual inspection of a subset of the images was carried out to assess the performance of different combinations of features (physical quantities, written in italic) in a particular gating task. The IDEAS software offers a suite of integrated tools for high-content image analysis and data visualization. We started by defining an appropriate mask, i. e. , the area of an image that will be used for further processing. Although the IDEAS software includes preloaded masks, it is possible to create customized ones by adjusting the channel and scalar values to better determine the section of the image that will be used for each feature computation.