A Novel Real-Time Echo Separation Processing Architecture for Space–Time Waveform-Encoding SAR Based on Elevation Digital Beamforming

Space–time waveform-encoding (STWE) SAR can receive echoes from multiple sub-swaths simultaneously with a single receive window. The echoes overlap each other in the time domain. To separate the echoes from different directions, traditional schemes adapt single-null steering techniques for digital receive beam patterns. However, the problems of spaceborne DBF-SAR, in practice, such as null extension loss, terrain undulation, elevation angle of arrival extension, and spaceborne antenna beam control, make the conventional scheme unable to effectively separate the echoes from different sub-swaths, which overlap each other in the time domain.A novel multi-null constrained echo separation scheme is proposed to overcome the shortcomings of the conventional scheme. The proposed algorithm can flexibly adjust the width of the notch to track the time-varying pulse extension angle with less resource consumption. Moreover, the hardware implementation details of the corresponding real-time processing architecture are discussed. The two-dimensional simulation results indicate that the proposed scheme can effectively improve the performance of echo separation. The effectiveness of the proposed method is verified by raw data processing instance of an X-band 16-channel DBF-SAR airborne system.

A Modified SLM Scheme for PAPR Reduction of UFMC Systems

One of the most promising 5G waveform candidates is the universal-filtered multicarrier system (UFMC). The UFMC system reduces the out-of-band (OoB) emission, bringing about higher spectral efficiency. This is assumed to reach robustness against frequency offset and low latency. Although, as aforementioned, the UFMC system offers many advantages, it lacks high peak-to-average power ratio (PAPR) as a multicarrier transmission technique. This research paper tackles two approaches; firstly, RCS, by developing a simulated conventional SLM system, with modifications to generate the same number of waveforms, while using fewer UFMC modulators. Secondly, by developing a simulated conventional SLM system, with modifications using the same number of modulators to generate more waveforms that would be generated in the conventional scheme. The two sets of results from the proposed M-SLM scheme are compared to each other, and to other PAPR reduction schemes using OFDM and UFMC. To reduce PAPR in UFMC systems, (M-SLM) scheme with low complexity is proposed. The essence of the proposed M-SLM scheme is represented in making use of the cyclically shifting process and FMC modulator’s linearity property. The proposed M-SLM scheme uses Um UFMC modulators to produce Uw alternative UFMC waveforms, where Uw = Um (2Um − 1). As a result, drawing a comparison with existing SLM based PAPR reduction schemes for UFMC systems; the proposed M-SLM scheme's computational complexity is reduced. Finally, there is a comparison between the proposed M-SLM scheme and the schemes there in the literature according to PAPR reduction ability.

The Optimized Cell Configuration Method of Avoiding SRS Inter-Cell Interference

The issue of cell-to-cell interferences is a serious problem that has always been raised in digital communication system such as NR. The communication method of NR and LTE is OFDM. OFDM has many advantages, but has fatal disadvantage called ICI (Inter-Cell Interference) because resources among cells are always overlapped. For example, NR’s typical interferences are ICIs among PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), PUSCH (Physical Uplink Shared Channel), PUCCH (Physical Uplink Control Channel), CSI-RS (Channel State Information-Reference Signal) and SRS (Sounding Reference Signal). Among them, it is important to determine the correct beamforming weight factor value by estimating the channel with SRS. Therefore, the ICI of SRS degrades the performance of downlink throughput. This paper analyses the impact of SRS’s ICI in conventional scheme, introduces the proposed AC-CS (Auto-Correlation Cyclic Shift) schemes by the Zadoff-Chu sequence to overcome the ICI of SRS and analyses theirs performance. The method used for performance analysis is determined by the detection abilities, which are missing probability and false alarm probability.

Deep Learning-Based Indoor Two-Dimensional Localization Scheme Using a Frequency-Modulated Continuous Wave Radar

In this paper, we propose a deep learning-based indoor two-dimensional (2D) localization scheme using a 24 GHz frequency-modulated continuous wave (FMCW) radar. In the proposed scheme, deep neural network and convolutional neural network (CNN) models that use different numbers of FMCW radars were employed to overcome the limitations of the conventional 2D localization scheme that is based on multilateration methods. The performance of the proposed scheme was evaluated experimentally and compared with the conventional scheme under the same conditions. According to the results, the 2D location of the target could be estimated with a proposed single radar scheme, whereas two FMCW radars were required by the conventional scheme. Furthermore, the proposed CNN scheme with two FMCW radars produced an average localization error of 0.23 m, while the error of the conventional scheme with two FMCW radars was 0.53 m.

Study on the effectiveness of chemical and biological agents to control tomato leaf miner (Tuta absoluta Meyrick, 1917)

In growing four tomato varieties in greenhouses, the effect of a conventional and integrated scheme for control of tomato leaf miner (Tuta absoluta Meyrick, 1917) was studied. Six consecutive treatments were performed at ten-day intervals. The conventional scheme includes the following products: Confidor Energy OD 0.08%, Ampligo 150 ZC 400 ml/ha, Coragen 20 SC 200 ml/ha, Exalt 25 SC 2400 ml/ha, Voliam Targo 063 SC 800 ml/ha and Voliam Targo 063 SC 800 ml/ha. In the integrated scheme the following products for plant protection are used – Confidor Energy OD 0.08%, Sineis 480 SC 250 ml/ha, Sineis 480 SC 250 ml/ha, Voliam Targo 063 SC 800 ml/ha, Neem Azal T/S 0.3% and Neem Azal T/S 0.3%. The effectiveness of the plant protection products against the tomato leaf miner, the degree of pest attack of the different varieties and the tomato productivity were studied in this experiment. It was established that in the conventional and in the integrated treatment scheme, the highest efficiency was shown by the product Voliam Targo 063 SC, applied in a dose of 800 ml/ha on the seventh day after spraying. The percentage of damaged plants was the lowest in the variety Clarosa F1 (4.00%), with the application of the conventional plant protection scheme. The results were similar in the integrated scheme – 6.00%, while in the control the degree of infestation reached 18.00%. The percentage of damaged fruits in both treatment schemes was 6.00%, significantly lower than in the control (24.00%). The highest tomato productivity was observed with the application of the conventional plant protection scheme in Manusa F1 variety.

Perceptual Data Embedding in Audio and Speech Signals

Perceptual embedding is a technique to embed extra information into multimedia signals without fidelity degradation, which is the core of many applications including watermarking and data hiding. Perceptual embedding can be viewed as a telecommunication to transmit the embedded information over the medium consisting of the host signal. This observation divides the current embedding techniques into two categories, i.e. the host-suppressing ones like the quantization-based Quantization Index Modulation (QIM) and Scalar Costa Scheme (SCS), and the non host-suppressing ones like the conventional Spread Spectrum (SS) technique. The former class has significant advantages over the latter in robustness and data rate due to significantly reduced noise levels. In this research, the conventional SS embedding technique is modified such that it can suppress the host impact mostly. Both the theoretical analysis and simulations show that the modification significantly improve the performance of the conventional scheme and further, outperform the QIM and SCS under the case of watermarking where the attacks can be expected to be very strong. To further increase the robustness and embedding rate, measures like frequency masking effects of the Human Masking Auditory system and Forward Error Correction schemes are employed, such as Turbo code. The second part of this research explores the possibility of high-capacity embedding in telephony speech signals. Another modification to improve the embedding rate is proposed for the conventional SS scheme under weak attacks, which are expected for the case of data embedding.

Perceptual Data Embedding in Audio and Speech Signals

Perceptual embedding is a technique to embed extra information into multimedia signals without fidelity degradation, which is the core of many applications including watermarking and data hiding. Perceptual embedding can be viewed as a telecommunication to transmit the embedded information over the medium consisting of the host signal. This observation divides the current embedding techniques into two categories, i.e. the host-suppressing ones like the quantization-based Quantization Index Modulation (QIM) and Scalar Costa Scheme (SCS), and the non host-suppressing ones like the conventional Spread Spectrum (SS) technique. The former class has significant advantages over the latter in robustness and data rate due to significantly reduced noise levels. In this research, the conventional SS embedding technique is modified such that it can suppress the host impact mostly. Both the theoretical analysis and simulations show that the modification significantly improve the performance of the conventional scheme and further, outperform the QIM and SCS under the case of watermarking where the attacks can be expected to be very strong. To further increase the robustness and embedding rate, measures like frequency masking effects of the Human Masking Auditory system and Forward Error Correction schemes are employed, such as Turbo code. The second part of this research explores the possibility of high-capacity embedding in telephony speech signals. Another modification to improve the embedding rate is proposed for the conventional SS scheme under weak attacks, which are expected for the case of data embedding.

Improved IMPES Scheme for the Simulation of Incompressible Three-Phase Flows in Subsurface Porous Media

In this work, an improved IMplicit Pressure and Explicit Saturation (IMPES) scheme is proposed to solve the coupled partial differential equations to simulate the three-phase flows in subsurface porous media. This scheme is the first IMPES algorithm for the three-phase flow problem that is locally mass conservative for all phases. The key technique of this novel scheme relies on a new formulation of the discrete pressure equation. Different from the conventional scheme, the discrete pressure equation in this work is obtained by adding together the discrete conservation equations of all phases, thus ensuring the consistency of the pressure equation with the three saturation equations at the discrete level. This consistency is important, but unfortunately it is not satisfied in the conventional IMPES schemes. In this paper, we address and fix an undesired and well-known consequence of this inconsistency in the conventional IMPES in that the computed saturations are conservative only for two phases in three-phase flows, but not for all three phases. Compared with the standard IMPES scheme, the improved IMPES scheme has the following advantages: firstly, the mass conservation of all the phases is preserved both locally and globally; secondly, it is unbiased toward all phases, i.e., no reference phases need to be chosen; thirdly, the upwind scheme is applied to the saturation of all phases instead of only the referenced phases; fourthly, numerical stability is greatly improved because of phase-wise conservation and unbiased treatment. Numerical experiments are also carried out to demonstrate the strength of the improved IMPES scheme.

Algorithm Of The Electronic Digital Subscript On The Basis Of The Composition Of Computing Complexities

In article the new algorithm of a digital signature in composition of the existing difficulties is developed: discrete logarithming in a final field, decomposition of rather large natural number on simple multipliers, additions of points with rational coordinates of an elliptic curve. On the basis of a combination of difficulties of discrete logarithming on a final field with the characteristic of large number, decomposition of rather large odd number on simple multipliers and additions of points of an elliptic curve develops algorithm of a digital signature for formation. The conventional scheme (model) of a digital signature covers three processes: generation of keys of EDS; formation of EDS; check (authenticity confirmation) of EDS. The idea of a design of the offered algorithm allows modifying and increasing crypto stability with addition to other computing difficulties. It is intended for use in systems of information processing of different function during forming and confirmation of authenticity of digital signature.

Finite-size correction for slab supercell calculations of materials with spontaneous polarization

The repeated slab approach has become a de facto standard to accurately describe surface properties of materials by density functional theory calculations with periodic boundary conditions. For materials exhibiting spontaneous polarization, we show that the conventional scheme of passivation with pseudo hydrogen is unable to realize a charge-neutral surface. The presence of a net surface charge induces via Gauss’s law a macroscopic electric field through the slab and results in poor size convergence with respect to the thickness of the slab. We propose a modified passivation method that accounts for the effect of spontaneous polarization, describes the correct bulk limits and boosts convergence with respect to slab thickness. The robustness, reliability, and superior convergence of energetics and electronic structure achieved by the proposed method are demonstrated using the example of polar ZnO surfaces.