Articoli di riviste: "Multi-Dimensional modulations"

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Mjølhus, E., e T. Hada. "Oblique stability of circularly polarized MHD waves". Journal of Plasma Physics 43, n. 2 (aprile 1990): 257–68. http://dx.doi.org/10.1017/s002237780001477x.

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The stability of finite-amplitude weakly dispersive circularly polarized MHD wave trains with respect to oblique modulations is investigated. The mathematical model is a multi-dimensional extension of the DNLS equation. We have found that the right-hand-polarized wave, which is stable with respect to parallel modulations, is unstable with respect to certain oblique modulations for most primary wavenumbers.

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Lidin, Sven, Partha Jana, Carola Müller, Shuying Piao e Simeon Ponou. "News from the world of modulated intermetallics". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C167. http://dx.doi.org/10.1107/s2053273314098325.

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The number of modulated structures with more than one modulation vector is small, and such structures often pose special problems in solving and refining. This talk will be concentrated on three such cases; The 3+4 dimensionally modulated cubic structure of digenite, the 3+2 dimensionally modulated structure of Cu3In2, the 3+2 dimensionally modulated structure of AuZn3 and the 3+2 dimensionally modulated structure of Se(Sn4)2K10. The three former cases are interesting because they are relatively weakly ordered structures where modelling is straight-forward, but the model itself is less than obvious to understand while the latter case appears highly ordered, but presents formal modelling difficulties. From these and previously known multi dimensional cases it would appear that higher order modulations are very prone to disorder. The image shows the hk0 layer from Se(Sn4)2K10.

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M. Navazi, Hassan, e Md Jahangir Hossain. "Novel Method for Multi-Dimensional Mapping of Higher Order Modulations for BICM-ID Over Rayleigh Fading Channels". IEEE Transactions on Wireless Communications 18, n. 2 (febbraio 2019): 1142–54. http://dx.doi.org/10.1109/twc.2018.2890061.

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Lu, Yi, Biao Tang, Guisong Yang, Yuanyuan Guo, Linwei Liu e Alex Henzen. "Progress in Advanced Properties of Electrowetting Displays". Micromachines 12, n. 2 (18 febbraio 2021): 206. http://dx.doi.org/10.3390/mi12020206.

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Electrowetting display (EWD) has promising prospects in the electronic paper industry due to it having superior characteristics, such as the ability to provide a comfortable reading experience and quick response. However, in real applications, there are also problems related to dielectric deterioration, excess power consumption, optical instability and narrow color gamut etc. This paper reviewed the existing challenges and recent progress made in terms of improving the optical performance and reliability of EWD. First, the principle of electrowetting applied in small and confined configurations is introduced and the cause of the failure of the dielectric layer is analyzed. Then, the function of the pixel structures is described to avoid display defects. Next, electric signal modulations are compared in terms of achieving good image quality and optical stability. Lastly, the methods are presented for color panel realization. It was concluded that multi-layer dielectrics, three-dimensional pixel structures, proper electric frequency-and-amplitude modulation and an RGB color panel are expected to resolve the current limitations and contribute to designing advanced reflective displays.

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Schoenberg, Poppy L. A., e Anne E. M. Speckens. "Multi-dimensional modulations of α and γ cortical dynamics following mindfulness-based cognitive therapy in Major Depressive Disorder". Cognitive Neurodynamics 9, n. 1 (29 agosto 2014): 13–29. http://dx.doi.org/10.1007/s11571-014-9308-y.

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Pier, Benoît, e Peter J. Schmid. "Linear and nonlinear dynamics of pulsatile channel flow". Journal of Fluid Mechanics 815 (21 febbraio 2017): 435–80. http://dx.doi.org/10.1017/jfm.2017.58.

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The dynamics of small-amplitude perturbations, as well as the regime of fully developed nonlinear propagating waves, is investigated for pulsatile channel flows. The time-periodic base flows are known analytically and completely determined by the Reynolds number $Re$ (based on the mean flow rate), the Womersley number $Wo$ (a dimensionless expression of the frequency) and the flow-rate waveform. This paper considers pulsatile flows with a single oscillating component and hence only three non-dimensional control parameters are present. Linear stability characteristics are obtained both by Floquet analyses and by linearized direct numerical simulations. In particular, the long-term growth or decay rates and the intracyclic modulation amplitudes are systematically computed. At large frequencies (mainly $Wo\geqslant 14$), increasing the amplitude of the oscillating component is found to have a stabilizing effect, while it is destabilizing at lower frequencies; strongest destabilization is found for $Wo\simeq 7$. Whether stable or unstable, perturbations may undergo large-amplitude intracyclic modulations; these intracyclic modulation amplitudes reach huge values at low pulsation frequencies. For linearly unstable configurations, the resulting saturated fully developed finite-amplitude solutions are computed by direct numerical simulations of the complete Navier–Stokes equations. Essentially two types of nonlinear dynamics have been identified: ‘cruising’ regimes for which nonlinearities are sustained throughout the entire pulsation cycle and which may be interpreted as modulated Tollmien–Schlichting waves, and ‘ballistic’ regimes that are propelled into a nonlinear phase before subsiding again to small amplitudes within every pulsation cycle. Cruising regimes are found to prevail for weak base-flow pulsation amplitudes, while ballistic regimes are selected at larger pulsation amplitudes; at larger pulsation frequencies, however, the ballistic regime may be bypassed due to the stabilizing effect of the base-flow pulsating component. By investigating extended regions of a multi-dimensional parameter space and considering both two-dimensional and three-dimensional perturbations, the linear and nonlinear dynamics are systematically explored and characterized.

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Chen Yanjie, 陈彦杰, 徐正琨 Xu Zhengkun, 赵睿哲 Zhao Ruizhe, 李晓炜 Li Xiaowei, 王涌天 Wang Yongtian e 黄玲玲 Huang Lingling. "多维度大容量超表面全息及光场变换". Acta Optica Sinica 44, n. 2 (2024): 0200005. http://dx.doi.org/10.3788/aos231100.

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Pegna, Alan J., Alexandra Darque, Mark V. Roberts e E. Charles Leek. "Effects of stereoscopic disparity on early ERP components during classification of three-dimensional objects". Quarterly Journal of Experimental Psychology 71, n. 6 (1 gennaio 2018): 1419–30. http://dx.doi.org/10.1080/17470218.2017.1333129.

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This study investigates the effects of stereo disparity on the perception of three-dimensional (3D) object shape. We tested the hypothesis that stereo input modulates the brain activity related to perceptual analyses of 3D shape configuration during image classification. High-density (256-channel) electroencephalogram (EEG) was used to record the temporal dynamics of visual shape processing under conditions of two-dimensional (2D) and 3D visual presentation. On each trial, observers made image classification judgements (‘Same’/’Different’) to two briefly presented, multi-part, novel objects. On different-object trials, stimuli could either share volumetric parts but not the global 3D shape configuration and have different parts but the same global 3D shape configuration or differ on both aspects. Analyses using mass univariate contrasts showed that the earliest sensitivity to 2D versus 3D viewing appeared as a negative deflection over posterior locations on the N1 component between 160 and 220 ms post-stimulus onset. Subsequently, event-related potential (ERP) modulations during the N2 time window between 240 and 370 ms were linked to image classification. N2 activity reflected two distinct components – an early N2 (240-290 ms) and a late N2 (290-370 ms) – that showed different patterns of responses to 2D and 3D input and differential sensitivity to 3D object structure. The results revealed that stereo input modulates the neural correlates of 3D object shape. We suggest that this reflects differential perceptual processing of object shape under conditions of stereo or mono input. These findings challenge current theories that attribute no functional role for stereo input during 3D shape perception.

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Zhu Chen, 朱宸, 邵正龙 Shao Zhenglong, 周英杰 Zhou Yingjie, 任佳琪 Ren Jiaqi, 樊帆 Fan Fan e 汤东亮 Tang Dongliang. "液晶的多维度光场调控技术研究进展". Chinese Journal of Lasers 50, n. 18 (2023): 1813006. http://dx.doi.org/10.3788/cjl230716.

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Fusaro, A., P. Loiseau, D. Penninckx, G. Riazuelo e R. Collin. "Improving stimulated Brillouin scattering mitigation in weakly-damped plasmas: from spectral dispersion to spectral distribution". Nuclear Fusion 61, n. 12 (15 novembre 2021): 126049. http://dx.doi.org/10.1088/1741-4326/ac31d9.

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Abstract Optical smoothing techniques are widely used in large high-power laser facilities designed for inertial confinement fusion research, such as the Laser Mégajoule (LMJ) in France. Those techniques are of primordial interest because they reduce laser–plasma instabilities as, for example, the stimulated backward Brillouin scattering (SBS). The latter takes place in the hot plasmas produced inside a hohlraum by the ablation of high-Z or gold material where ion acoustic waves are weakly damped, easing SBS. However, despite the current optical smoothing implementation, like smoothing by spectral dispersion (SSD), SBS is not sufficiently mitigated and may also damage the laser optics by following back the laser path. Moreover, SSD limits the available energy and may produce unwanted amplitude modulations in the laser chain, resulting in an additional damage. Using spectral distribution with two colors (Duluc et al 2019 Phys. Rev. Appl. 12 054055) has proven to limit the latter damage, keeping the same efficiency for limiting SBS. In this study, we go a step forward and generalize this approach by exploring multi-color spectral distribution schemes and the role of dispersion by means of three-dimensional simulations. This study paves the road to new laser concepts that could tackle more efficiently the laser–plasma interaction issues leading to a better laser energy coupling.

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Ekengoue, C. M., C. Kenfack-Sadem, J. E. Danga, G. N. Bawe, A. El Moussaouy, O. Mommadi, L. Belamkadem e L. C. Fai. "Polariton condensate and Landau-Zener-Stückelberg interferometry transition in multilayer transition metal dichalcogenides". Physica Scripta 97, n. 2 (13 gennaio 2022): 025801. http://dx.doi.org/10.1088/1402-4896/ac4718.

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Abstract This paper gives a detailed description of a high-performance polariton condensate for a quantum mechanical two-level system (TLS). We propose a transition metal dichalcogenides (TMDs) setup and theoretically carry out the spectroscopy of these polariton condensates. Through theoretical and numerical analysis, we obtain many features in two dimensional (2D) multilayer TMDs. We compute the energy of the system and the Landau-Zener-Stückelberg (LZS) quantum tunneling probability under the effect of a sequence of laser light. At certain critical 2D TMDs parameters, the system exhibits a multi-crossing scenario in a privileged position of 2D multilayer TMDs. We predict the consecutive modulations and highlight the conservation of the LZS interference patterns mapped from the 2D TMDs system. At weak coupling regime, a successful conversion of interferometry signals is identified for some values of laser frequency. We explain such a result as a valley sensitive cavity rate model due to coherent exchange and incoherent scattering, meaning that polariton condensate is formed in the valley around the Brillouin zone. The latter is used quantitatively and qualitatively to achieve high-precision measurements beyond that of its elementary constituents. The obtained results confirm that M o S e 2 has the highest sensitivity to radiation field as compared to other 2D multilayer TMDs materials. Therefore, M o S e 2 stands as an appropriate candidate among other 2D TMDs to form polariton condensates.

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Feng, Dan, Qingli He, Baoming Bai, Jianping Zheng e Mengmeng Liu. "Spatial Modulation With Multi-Dimensional Constellations". IEEE Wireless Communications Letters 9, n. 1 (gennaio 2020): 99–102. http://dx.doi.org/10.1109/lwc.2019.2943341.

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Lu, Siyao, Ibrahim A. Hemadeh, Mohammed El-Hajjar e Lajos Hanzo. "Compressed Sensing-Aided Multi-Dimensional Index Modulation". IEEE Transactions on Communications 67, n. 6 (giugno 2019): 4074–87. http://dx.doi.org/10.1109/tcomm.2019.2902393.

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Worts, Nathan, John Czerski, Jason Jones, Jeffrey J. Field, Randy Bartels e Jeff Squier. "Simultaneous multi-dimensional spatial frequency modulation imaging". International Journal of Optomechatronics 14, n. 1 (1 gennaio 2020): 1–17. http://dx.doi.org/10.1080/15599612.2019.1694610.

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Li, Bin, Lu Bo Li e Gui Dan Li. "Non-Sinusoidal SVPWM for Five-Phase Inverter Based on MMF Equivalence". Advanced Materials Research 694-697 (maggio 2013): 1524–31. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.1524.

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The multi-phase inverter modulation and control method is a hotspot of multiphase systems. There is no general space vector modulation available due to the inherent difficulty in synthesizing more than one independent space vector simultaneously in different d-p planes. This paper established the distribution model of five-phase inverter space vector from a novel perspective of magnetic motive force (MMF) equivalence. And then a multi-dimensional SVPMW method applicable to the non-sinusoidal voltage output was proposed based on the obtained space vector distribution laws. The proposed multi-dimensional SVPWM method effectively improves the fundamental modulation range and is suitable for five-phase inverter non-sinusoidal modulation.

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Qian, Liangxin, Ping Yang, Yong Liang Guan, Zilong Liu, Yue Xiao, Ke Jiang e Ming Xiao. "Multi-Dimensional Polarized Modulation for Land Mobile Satellite Communications". IEEE Transactions on Cognitive Communications and Networking 7, n. 2 (giugno 2021): 383–97. http://dx.doi.org/10.1109/tccn.2021.3072593.

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Naka, Akira, e Shota Yamada. "Characteristics of multi-dimensional modulation with MIMO signal processing". IEICE Communications Express 5, n. 12 (2016): 461–66. http://dx.doi.org/10.1587/comex.2016xbl0160.

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Ishimura, Shota, e Kazuro Kikuchi. "Multi-dimensional permutation-modulation format for coherent optical communications". Optics Express 23, n. 12 (4 giugno 2015): 15587. http://dx.doi.org/10.1364/oe.23.015587.

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Ko, Youngwook, e Jinho Choi. "Unsupervised Machine Intelligence for Automation of Multi-Dimensional Modulation". IEEE Communications Letters 23, n. 10 (ottobre 2019): 1783–86. http://dx.doi.org/10.1109/lcomm.2019.2932417.

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He, Zilong, Wentao Liu, Sheping Shi, Bailin Shen, Xue Chen, Xiqing Gao, Qi Zhang, Dongdong Shang, Yongning Ji e Yingfeng Liu. "Flexible multi-dimensional modulation method for elastic optical networks". Optics Communications 359 (gennaio 2016): 304–10. http://dx.doi.org/10.1016/j.optcom.2015.09.098.

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Xiao, Yan, Kehui Sun, Mengyao Yu e Xuemei Xu. "Dynamics of a New Multi-Cavity Hyperchaotic Map and Its DSP Implementation". International Journal of Bifurcation and Chaos 29, n. 14 (26 dicembre 2019): 1950194. http://dx.doi.org/10.1142/s0218127419501943.

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A new higher-dimensional hyperchaotic map, named Sine Chebyshev modulation map (SCMM), is proposed based on the closed-loop modulation coupling (CMC) model. The dynamics of the SCMM are evaluated by attractor diagrams, Lyapunov exponents and bifurcations. By designing a piecewise-linear function, the SCMM is expanded to the grid multi-cavity form. Dynamical behaviors of the two-dimensional grid multi-cavity SCMM are then analyzed. The results show that it has rich dynamical characteristics, including complicated phase space trajectories, hyperchaotic behaviors, large maximum Lyapunov exponent and typical bifurcations. The complexity of the new grid multi-cavity hyperchaotic map is large in the entire parameter space. Finally, digital circuits of 2D-SCMM and 2D grid multi-cavity SCMM are implemented based on the DSP technique. The feasibility of the circuit is verified, and it lays the foundation for applications in chaotic secure communication.

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Peng, Zhichao, Hua Zeng, Yongwei Li, Yegang Du e Jianwu Dang. "Enhancing Dimensional Emotion Recognition from Speech through Modulation-Filtered Cochleagram and Parallel Attention Recurrent Network". Electronics 12, n. 22 (12 novembre 2023): 4620. http://dx.doi.org/10.3390/electronics12224620.

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Dimensional emotion can better describe rich and fine-grained emotional states than categorical emotion. In the realm of human–robot interaction, the ability to continuously recognize dimensional emotions from speech empowers robots to capture the temporal dynamics of a speaker’s emotional state and adjust their interaction strategies in real-time. In this study, we present an approach to enhance dimensional emotion recognition through modulation-filtered cochleagram and parallel attention recurrent neural network (PA-net). Firstly, the multi-resolution modulation-filtered cochleagram is derived from speech signals through auditory signal processing. Subsequently, the PA-net is employed to establish multi-temporal dependencies from diverse scales of features, enabling the tracking of the dynamic variations in dimensional emotion within auditory modulation sequences. The results obtained from experiments conducted on the RECOLA dataset demonstrate that, at the feature level, the modulation-filtered cochleagram surpasses other assessed features in its efficacy to forecast valence and arousal. Particularly noteworthy is its pronounced superiority in scenarios characterized by a high signal-to-noise ratio. At the model level, the PA-net attains the highest predictive performance for both valence and arousal, clearly outperforming alternative regression models. Furthermore, the experiments carried out on the SEWA dataset demonstrate the substantial enhancements brought about by the proposed method in valence and arousal prediction. These results collectively highlight the potency and effectiveness of our approach in advancing the field of dimensional speech emotion recognition.

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Xue, Ju-Kui. "Modulational instability of multi-dimensional dust ion-acoustic waves". Physics Letters A 330, n. 5 (settembre 2004): 390–95. http://dx.doi.org/10.1016/j.physleta.2004.08.013.

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Jiang, Yingchun, e Jing Yang. "Nonuniform Sampling in Lp-Subspaces Associated with the Multi-Dimensional Special Affine Fourier Transform". Axioms 13, n. 5 (15 maggio 2024): 329. http://dx.doi.org/10.3390/axioms13050329.

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In this paper, the sampling and reconstruction problems in function subspaces of Lp(Rn) associated with the multi-dimensional special affine Fourier transform (SAFT) are discussed. First, we give the definition of the multi-dimensional SAFT and study its properties including the Parseval’s relation, the canonical convolution theorems and the chirp-modulation periodicity. Then, a kind of function spaces are defined by the canonical convolution in the multi-dimensional SAFT domain, the existence and the properties of the dual basis functions are demonstrated, and the Lp-stability of the basis functions is established. Finally, based on the nonuniform samples taken on a dense set, we propose an iterative reconstruction algorithm with exponential convergence to recover the signals in a Lp-subspace associated with the multi-dimensional SAFT, and the validity of the algorithm is demonstrated via simulations.

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Naka, Akira. "BER performance analysis of multi-dimensional modulation with BICM-ID". IEICE Communications Express 6, n. 12 (2017): 645–50. http://dx.doi.org/10.1587/comex.2017xbl0123.

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Zhang, Hongbin, Hussam G. Batshon, Carl R. Davidson, Dmitri G. Foursa e Alexei Pilipetskii. "Multi-Dimensional Coded Modulation in Long-Haul Fiber Optic Transmission". Journal of Lightwave Technology 33, n. 13 (1 luglio 2015): 2876–83. http://dx.doi.org/10.1109/jlt.2015.2419821.

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Wang Xudong, 王旭东, 刘莹 Liu Ying, 吴楠 Wu Nan e 林彬 Lin Bin. "Hybrid Multi-Dimensional CAP-MPPM Modulation Scheme for VLC Systems". Chinese Journal of Lasers 47, n. 6 (2020): 0606004. http://dx.doi.org/10.3788/cjl202047.0606004.

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Kim, Tae, e Dong Kim. "Multi-Dimensional Sparse-Coded Ambient Backscatter Communication for Massive IoT Networks". Energies 11, n. 10 (22 ottobre 2018): 2855. http://dx.doi.org/10.3390/en11102855.

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In this paper, we propose a multi-dimensional sparse-coded ambient backscatter communication (MSC-AmBC) system for long-range and high-rate massive Internet of things (IoT) networks. We utilize the characteristics of the ambient sources employing orthogonal frequency division multiplexing (OFDM) modulation to mitigate strong direct-link interference and improve signal detection of AmBC at the reader. Also, utilization of the sparsity originated from the duty-cycling operation of batteryless RF tags is proposed to increase the dimension of signal space of backscatter signals to achieve either diversity or multiplexing gains in AmBC. We propose optimal constellation mapping and reflection coefficient projection and expansion methods to effectively construct multi-dimensional constellation for high-order backscatter modulation while guaranteeing sufficient energy harvesting opportunities at these tags. Simulation results confirm the feasibility of the long-range and high-rate AmBC in massive IoT networks where a huge number of active ambient sources and passive RF tags coexist.

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Hao, Ming, Wei He, Xuedong Jiang, Shuai Liang, Wei Jin, Lin Chen e Jianming Tang. "Modulation Format Identification Based on Multi-Dimensional Amplitude Features for Elastic Optical Networks". Photonics 11, n. 5 (23 aprile 2024): 390. http://dx.doi.org/10.3390/photonics11050390.

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A modulation format identification (MFI) scheme based on multi-dimensional amplitude features is proposed for elastic optical networks. According to the multi-dimensional amplitude features, incoming polarization division multiplexed (PDM) signals can be identified as QPSK, 8QAM, 16QAM, 32QAM, 64QAM and 128QAM signals using the k-nearest neighbors (KNNs) algorithm in the digital coherent receivers. The proposed scheme does not require any prior training or optical signal-to-noise ratio (OSNR) information. The performance of the proposed MFI scheme is verified based on numerical simulations with 28GBaud PDM-QPSK/-8QAM/-16QAM/-32QAM/-64QAM/-128QAM signals. The results show that the proposed scheme can achieve 100% of the correct MFI rate for all six modulation formats when the OSNR values are greater than their thresholds corresponding to the 20% forward error correction (FEC) related to a BER of 2.4 × 10−2. Meanwhile, the effects of residual chromatic dispersion, polarization mode dispersion and fiber nonlinearities on the proposed scheme are also explored. Finally, the computational complexity of the proposed scheme is analyzed, which is compared with relevant MFI schemes. The work indicates that the proposed technique could be regarded as a good candidate for identifying modulation formats up to 128QAM.

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Ha, Inho, Joung-Moon Lee e Sang-Kook Han. "SOP Change Robust Optical Modulation Based on Dual Polarization Modulation for Multi-Dimensional Optical Transmission". IEEE Access 9 (2021): 119139–46. http://dx.doi.org/10.1109/access.2021.3106904.

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El-Hajjar, Mohammed, Osamah Alamri, Jin Wang, Salam Zummo e Lajos Hanzo. "Layered steered space-time codes using multi-dimensional sphere packing modulation". IEEE Transactions on Wireless Communications 8, n. 7 (luglio 2009): 3335–40. http://dx.doi.org/10.1109/twc.2009.071292.

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Kassouf, Marthe, e Harry Leib. "Information rates for multi-dimensional modulation over multiple antenna wireless channels". European Transactions on Telecommunications 20, n. 5 (agosto 2009): 463–81. http://dx.doi.org/10.1002/ett.1318.

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Peng, Zhichao, Wenhua He, Yongwei Li, Yegang Du e Jianwu Dang. "Multi-Level Attention-Based Categorical Emotion Recognition Using Modulation-Filtered Cochleagram". Applied Sciences 13, n. 11 (1 giugno 2023): 6749. http://dx.doi.org/10.3390/app13116749.

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Abstract (sommario):

Speech emotion recognition is a critical component for achieving natural human–robot interaction. The modulation-filtered cochleagram is a feature based on auditory modulation perception, which contains multi-dimensional spectral–temporal modulation representation. In this study, we propose an emotion recognition framework that utilizes a multi-level attention network to extract high-level emotional feature representations from the modulation-filtered cochleagram. Our approach utilizes channel-level attention and spatial-level attention modules to generate emotional saliency maps of channel and spatial feature representations, capturing significant emotional channel and feature space from the 3D convolution feature maps, respectively. Furthermore, we employ a temporal-level attention module to capture significant emotional regions from the concatenated feature sequence of the emotional saliency maps. Our experiments on the Interactive Emotional Dyadic Motion Capture (IEMOCAP) dataset demonstrate that the modulation-filtered cochleagram significantly improves the prediction performance of categorical emotion compared to other evaluated features. Moreover, our emotion recognition framework achieves comparable unweighted accuracy of 71% in categorical emotion recognition by comparing with several existing approaches. In summary, our study demonstrates the effectiveness of the modulation-filtered cochleagram in speech emotion recognition, and our proposed multi-level attention framework provides a promising direction for future research in this field.

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Zhang, Shuai, Heng Wang, Yan Pan, Yun Shao, Tao Zhang, Wei Huang, Yang Li e Bingjie Xu. "A Novel Continuous-Variable Quantum Key Distribution Scheme Based on Multi-Dimensional Multiplexing Technology". Applied Sciences 14, n. 2 (22 gennaio 2024): 934. http://dx.doi.org/10.3390/app14020934.

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Dual-polarization division multiplexing (DPDM) is considered to be a potential method to boost the secure key rate (SKR) of the continuous-variable quantum key distribution (CV-QKD) system. In this article, we propose a pilot alternately assisted local local oscillator (LLO) CV-QKD scheme based on multi-dimensional multiplexing, where time division multiplexing and frequency division multiplexing are combined with dual-polarization multiplexing techniques to dramatically isolate the quantum signal from the pilot tone. We establish a general excess noise model for the LLO CV-QKD system to analyze the influence mechanism of various disturbances (e.g., time-domain diffusion, frequency-domain modulation residual, and polarization perturbation) on the key parameters, such as the channel transmittance and excess noise. Specifically, the photon leakage noise from the reference path to the quantum path and that between quantum signals with two different polarization paths are simultaneously analyzed in the dual-polarization LLO CV-QKD scheme for the first time. Furthermore, a series of simulations are established to verify the performance of the proposed scheme. The results show that the maximal isolation degree achieves 84.0 dB~90.4 dB, and the crosstalk between pilot tones and quantum signals can be suppressed to a very small range. By optimizing the system parameters (e.g., modulation variance and repetition frequency), the SKR with 12.801 Mbps@25 km is achieved under the infinite polarization extinction ratio (PER) and 30 dB residual ratio of the frequency modulation in the nanosecond-level pulse width. Moreover, the performance of the proposed DPDM CV-QKD scheme under relatively harsh conditions is simulated; the results show that the SKR with 1.02 Mbps@25 km is achieved under a relatively low PER of 17 dB with the nanosecond-level pulse width and 20 dB residual ratio of the frequency modulation. Our work lays an important theoretical foundation for the practical DPDM LLO CV-QKD system.

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Lu, Siyao, Mohammed El-Hajjar e Lajos Hanzo. "Two-Dimensional Index Modulation for the Large-Scale Multi-User MIMO Uplink". IEEE Transactions on Vehicular Technology 68, n. 8 (agosto 2019): 7904–18. http://dx.doi.org/10.1109/tvt.2019.2926884.

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Su, Guangxu, Jiangle He, Xiaofei Ye, Hengming Yao, Yaxuan Li, Junzheng Hu, Minghui Lu, Peng Zhan e Fanxin Liu. "Tailored Triggering of High-Quality Multi-Dimensional Coupled Topological States in Valley Photonic Crystals". Nanomaterials 14, n. 10 (19 maggio 2024): 885. http://dx.doi.org/10.3390/nano14100885.

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The combination of higher-order topological insulators and valley photonic crystals has recently aroused extensive attentions due to the great potential in flexible and efficient optical field manipulations. Here, we computationally propose a photonic device for the 1550 nm communication band, in which the topologically protected electromagnetic modes with high quality can be selectively triggered and modulated on demand. Through introducing two valley photonic crystal units without any structural alteration, we successfully achieve multi-dimensional coupled topological states thanks to the diverse electromagnetic characteristics of two valley edge states. According to the simulations, the constructed topological photonic devices can realize Fano lines on the spectrum and show high-quality localized modes by tuning the coupling strength between the zero-dimensional valley corner states and the one-dimensional valley edge states. Furthermore, we extend the valley-locked properties of edge states to higher-order valley topological insulators, where the selected corner states can be directionally excited by chiral source. More interestingly, we find that the modulation of multi-dimensional coupled photonic topological states with pseudospin dependence become more efficient compared with those uncoupled modes. This work presents a valuable approach for multi-dimensional optical field manipulation, which may support potential applications in on-chip integrated nanophotonic devices.

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García, A. G., M. A. Hernández-Medina e G. Pérez-Villalón. "Filter banks on discrete abelian groups". International Journal of Wavelets, Multiresolution and Information Processing 16, n. 04 (luglio 2018): 1850029. http://dx.doi.org/10.1142/s0219691318500297.

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In this work, we provide polyphase, modulation, and frame theoretical analyses of a filter bank on a discrete abelian group. Thus, multi-dimensional or cyclic filter banks as well as filter banks for signals in [Formula: see text] or [Formula: see text] spaces are studied in a unified way. We obtain perfect reconstruction conditions and the corresponding frame bounds in this particular context.

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Riahi, D. N. "Preferred pattern of convection in a porous layer with a spatially non-uniform boundary temperature". Journal of Fluid Mechanics 246 (gennaio 1993): 529–43. http://dx.doi.org/10.1017/s0022112093000254.

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The problem of finite-amplitude thermal convection in a porous layer between two horizontal walls with different mean temperatures is considered when spatially non-uniform temperature with amplitude L* is prescribed at the lower wall. The nonlinear problem of three-dimensional convection for values of the Rayleigh number close to the classical critical value is solved by using a perturbation technique. Two cases are considered: the wavelength γ(b)n of the nth mode of the modulation is equal to or not equal to the critical wavelength γc for the onset of classical convection. The preferred mode of convection is determined by a stability analysis in which arbitrary infinitesimal disturbances are superimposed on the steady solutions. The most surprising results for the case γ(b)n = γc for all n are that regular or non-regular solutions in the form of multi-modal pattern convection can become preferred in some range of L*, provided the wave vectors of such pattern are contained in the set of wave vectors representing the spatially non-uniform boundary temperature. There can be critical value(s) L*c of L* below which the preferred flow pattern is different from the one for L* > L*c. The most surprising result for the case γ(b)n ≠ γc and γ(b)n ≡ γ(b) for all n is that some three-dimensional solution in the form of multi-modal convection can be preferred, even if the boundary modulation is one-dimensional, provided that the wavelength of the modulation is not too small. Here γ(b) is a constant independent of n.

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Li, Chuanqing, Yi Liu, Fugang Sun, Teng Ma, Weidong Wan e Yi Liu. "Space–frequency‐mode multi‐dimensional hybrid modulation for vortex wave MIMO‐OFDM systems". IET Communications 15, n. 7 (25 febbraio 2021): 924–34. http://dx.doi.org/10.1049/cmu2.12130.

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KASSOUF, Marthe, e Harry LEIB. "Achievable Rate Regions for Orthogonally Multiplexed MIMO Broadcast Channels with Multi-Dimensional Modulation". International Journal of Communications, Network and System Sciences 03, n. 01 (2010): 1–18. http://dx.doi.org/10.4236/ijcns.2010.31001.

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Durán, M., S. Toral, F. Barrero e E. Levi. "Real-time implementation of multi-dimensional five-phase space vector pulse-width modulation". Electronics Letters 43, n. 17 (2007): 949. http://dx.doi.org/10.1049/el:20071357.

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Sumiyoshitani, Satoru. "Localized multi-alternating-current modulation Kerr measurement of nonuniform three-dimensional electric fields". Applied Optics 34, n. 22 (1 agosto 1995): 4772. http://dx.doi.org/10.1364/ao.34.004772.

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Du, Haiwei, Tao Wan, Bo Qu, Jason Scott, Xi Lin, Adnan Younis e Dewei Chu. "Tailoring the multi-functionalities of one-dimensional ceria nanostructures via oxygen vacancy modulation". Journal of Colloid and Interface Science 504 (ottobre 2017): 305–14. http://dx.doi.org/10.1016/j.jcis.2017.05.057.

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Borio, Daniele. "A Vector Representation of Multicomplex Numbers and Its Application to Radio Frequency Signals". Axioms 13, n. 5 (14 maggio 2024): 324. http://dx.doi.org/10.3390/axioms13050324.

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Hypercomplex numbers, which are multi-dimensional extensions of complex numbers, have been proven beneficial in the development of advanced signal processing algorithms, including multi-dimensional filter design, linear regression and classification. We focus on multicomplex numbers, sets of hypercomplex numbers with commutative products, and introduce a vector representation allowing one to isolate the hyperbolic real and imaginary parts of a multicomplex number. The orthogonal decomposition of a multicomplex number is also discussed, and its connection with Hadamard matrices is highlighted. Finally, a multicomplex polar representation is provided. These properties are used to extend the standard complex baseband signal representation to the multi-dimensional case. It is shown that a set of 2n Radio Frequency (RF) signals can be represented as the real part of a single multicomplex signal modulated by several frequencies. The signal RFs are related through a Hadamard matrix to the modulating frequencies adopted in the multicomplex baseband representation. Moreover, an orthogonal decomposition is provided for the obtained multicomplex baseband signal as a function of the complex baseband representations of the input RF signals.

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Thapa, Dinesh, Leon N. Warne e Marco Falasca. "Pharmacohistory of Cannabis Use—A New Possibility in Future Drug Development for Gastrointestinal Diseases". International Journal of Molecular Sciences 24, n. 19 (28 settembre 2023): 14677. http://dx.doi.org/10.3390/ijms241914677.

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Humans have employed cannabis for multiple uses including medicine, recreation, food, and fibre. The various components such as roots, flowers, seeds, and leaves have been utilized to alleviate pain, inflammation, anxiety, and gastrointestinal disorders like nausea, vomiting, diarrhoea, and inflammatory bowel diseases (IBDs). It has occupied a significant space in ethnomedicines across cultures and religions. Despite multi-dimensional uses, the global prohibition of cannabis by the USA through the introduction of the Marijuana Tax Act in 1937 led to prejudice about the perceived risks of cannabis, overshadowing its medicinal potential. Nevertheless, the discovery of tetrahydrocannabinol (THC), the primary psychoactive compound in cannabis, and the endocannabinoid system renewed scientific interest in understanding the role of cannabis in modulating different conditions, including gastrointestinal disorders. Preparations combining cannabidiol and THC have shown promise in mitigating gut symptoms through anti-inflammatory and motility-enhancing effects. This review revisits the ethnomedicinal use of cannabis in gastrointestinal diseases and emphasizes the need for further research to determine optimal dosages, formulations, and safety profiles of cannabis-based medicines. It also underscores the future potential of cannabinoid-based therapies by leveraging the role of the expanded endocannabinoid system, an endocannabinoidome, in the modulation of gastrointestinal ailments.

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Vyunishev, A. M., V. G. Arkhipkin e A. S. Chirkin. "Frequency doubling of femtosecond laser pulses in three dimensional nonlinear photonic crystals". Laser Physics Letters 20, n. 3 (9 febbraio 2023): 035402. http://dx.doi.org/10.1088/1612-202x/acb7f5.

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Abstract Quasi-phase matched nonlinear frequency conversion in three dimensional nonlinear photonic crystals (NPCs) has been considered for implementation of the second harmonic generation of transform-limited and chirped femtosecond laser pulses. Spatial distribution of the second harmonic intensity is shown to be caused by Cherenkov- and Raman–Nath-type nonlinear diffraction. These types of nonlinear diffraction may occur simultaneously resulting in an efficient multi-order nonlinear diffraction in the Bragg regime, which can be realized by a proper choice of the modulation period of NPC structure in longitudinal direction for considered transverse diffraction order. Three dimensional NPCs open up new possibilities for ultrafast nonlinear photonics and parametric interactions in optics.

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Murtala, Sheriff, Tasnim Holoubi, Nishal Muchena, Manar Mohaisen e Kang-Sun Choi. "On the Performance of the Multiple Active Antenna Spatial Modulation with 3-Dimensional Constellation". Applied Sciences 10, n. 11 (27 maggio 2020): 3718. http://dx.doi.org/10.3390/app10113718.

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In spatial modulation (SM), a single signal symbol is transmitted from a given physical antenna, where both the signal symbol and the antenna index carry information. SM with multiple active antennas (MA-SM) transmits several signal symbols from a combination of antennas at each channel use, thereby increasing the spectral efficiency. MA-SM is proposed in combination with a new 3-dimensional constellation, where signal symbols transmitted from a given antenna combination are rotated before transmission. In this paper, we derived an upper-bound on the error probability of the MA-SM as a function of the rotation angles. The search for the optimal rotation angles is modeled as a multi-objective optimization problem. We concluded based on both analytical and simulation results that the 3-dimensional constellation with the optimal angles achieved negligible improvement. Therefore, we do not recommend using the 3-dimensional constellation with the MA-SM system.

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Peng, Zhichao, Jianwu Dang, Masashi Unoki e Masato Akagi. "Multi-resolution modulation-filtered cochleagram feature for LSTM-based dimensional emotion recognition from speech". Neural Networks 140 (agosto 2021): 261–73. http://dx.doi.org/10.1016/j.neunet.2021.03.027.

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Takahashi, Takumi, Shinsuke Ibi e Seiichi Sampei. "Design of Adaptively Scaled Belief in Multi-Dimensional Signal Detection for Higher-Order Modulation". IEEE Transactions on Communications 67, n. 3 (marzo 2019): 1986–2001. http://dx.doi.org/10.1109/tcomm.2018.2883307.

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Shahmansouri, M., e A. P. Misra. "Modulation and nonlinear evolution of multi-dimensional Langmuir wave envelopes in a relativistic plasma". Physics of Plasmas 23, n. 12 (dicembre 2016): 122112. http://dx.doi.org/10.1063/1.4971444.

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