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Showing papers on "Offset (computer science) published in 2022"


Journal ArticleDOI
TL;DR: In this article , the authors proposed a novel integrated mixed reality (MR) system for safety-aware human-robot collaboration using deep learning and digital twin generation, which can accurately measure the minimum safe distance in real-time and provide MR-based task assistance to the human operator.
Abstract: For human-robot collaboration (HRC), one of the most practical methods to ensure human safety with a vision-based system is establishing a minimum safe distance. This study proposes a novel integrated mixed reality (MR) system for safety-aware HRC using deep learning and digital twin generation. The proposed approach can accurately measure the minimum safe distance in real-time and provide MR-based task assistance to the human operator. The approach integrates MR with safety-related monitoring by tracking the shared workplace and providing user-centric visualization through smart MR glasses for safe and effective HRC. Two RGB-D sensors are used to reconstruct and track the working environment. One sensor scans one area of the physical environment through 3D point cloud data. The other also scans another area of the environment and tracks the user's 3D skeletal information. In addition, the two partially scanned environments are registered together by applying a fast global registration method to two sets of the 3D point cloud. Furthermore, deep learning-based instance segmentation is applied to the target object's 3D point cloud to increase the registration between the real robot and its virtual robot, the digital twin of the real robot. While only 3D point cloud data are widely used in previous studies, this study proposes a simple yet effective 3D offset-based safety distance calculation method based on the robot's digital twin and the human skeleton. The 3D offset-based method allows for real-time applicability without sacrificing the accuracy of safety distance calculation for HRI. In addition, two comparative evaluations were conducted to confirm the originality and advantage of the proposed MR-based HRC.

53 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a novel integrated mixed reality (MR) system for safety-aware human-robot collaboration using deep learning and digital twin generation, which can accurately measure the minimum safe distance in real-time and provide MR-based task assistance to the human operator.
Abstract: For human-robot collaboration (HRC), one of the most practical methods to ensure human safety with a vision-based system is establishing a minimum safe distance. This study proposes a novel integrated mixed reality (MR) system for safety-aware HRC using deep learning and digital twin generation. The proposed approach can accurately measure the minimum safe distance in real-time and provide MR-based task assistance to the human operator. The approach integrates MR with safety-related monitoring by tracking the shared workplace and providing user-centric visualization through smart MR glasses for safe and effective HRC. Two RGB-D sensors are used to reconstruct and track the working environment. One sensor scans one area of the physical environment through 3D point cloud data. The other also scans another area of the environment and tracks the user's 3D skeletal information. In addition, the two partially scanned environments are registered together by applying a fast global registration method to two sets of the 3D point cloud. Furthermore, deep learning-based instance segmentation is applied to the target object's 3D point cloud to increase the registration between the real robot and its virtual robot, the digital twin of the real robot. While only 3D point cloud data are widely used in previous studies, this study proposes a simple yet effective 3D offset-based safety distance calculation method based on the robot's digital twin and the human skeleton. The 3D offset-based method allows for real-time applicability without sacrificing the accuracy of safety distance calculation for HRI. In addition, two comparative evaluations were conducted to confirm the originality and advantage of the proposed MR-based HRC.

53 citations



Journal ArticleDOI
TL;DR: A scale-aware feature pyramid network (SARFNet) is proposed in this study, which comprises a scale-adaptive feature extraction module and a learnable anchor assignment strategy and is demonstrated to outperform existing boat detectors.
Abstract: Multi-scale object detection within Synthetic Aperture Radar (SAR) images has become a research hotspot in SAR image interpretation. Over the past few years, CNN-based detectors have advanced sharply in SAR object detection. However, the state-of-the-art detection methods are continuously limited in Feature Pyramid Network (FPN) designing and detection anchor setting aspects due to feature misalignment and targets’ appearance variation (i.e., scale change, aspect ratio change). To address the mentioned limitations, a scale-aware feature pyramid network (SARFNet) is proposed in this study, which comprises a scale-adaptive feature extraction module and a learnable anchor assignment strategy. To be specific, an enhanced feature pyramid sub-network is developed by introducing a feature alignment module to estimate the pixel offset and contextually align the high-level features. Moreover, a scale-equalizing pyramid convolution is built through 3-D convolution within the feature pyramid to improve inter-scale correlation at different feature levels. Furthermore, a self-learning anchor assignment is set to update hand-crafted anchor assignments to learnable anchor/feature configuration. By using the dynamic anchors, the detector of this study is capable of flexibly matching the target with different appearance changes. According to extensive experiments on public SAR image data sets (SSDD and HRSID), our algorithm is demonstrated to outperform existing boat detectors.

29 citations


Journal ArticleDOI
Yasunari Tamai1
01 Jan 2022
TL;DR: In this article , the authors examined the mechanisms underlying the free carrier generation in a very topical PM6/Y6 organic solar cell and observed slow yet efficient spatial charge dissociation driven by downhill energy relaxation through the interfacial energy cascade.
Abstract: We examined the mechanisms underlying the free carrier generation in a very topical PM6/Y6 organic solar cell. We observed slow yet efficient spatial charge dissociation driven by downhill energy relaxation through the interfacial energy cascade.

27 citations


Journal ArticleDOI
TL;DR: In this paper , an optimized design of (FAPbI3)1-x(MAPbBr3)x perovskite solar cell is numerically investigated using SCAPS-1D software package.
Abstract: In this paper, an optimized design of (FAPbI3)1-x(MAPbBr3)x perovskite solar cell is numerically investigated using SCAPS-1D software package. A variety of potential charge transport materials are investigated. Cu2O as HTL and ZnO as ETL outperform other choices; they are therefore considered as the best candidates. The impact of the electronic properties of both ZnO/perovskite and Perovskite/Cu2O interfaces on the solar cell performance is thoroughly investigated. We discovered that appropriate values of the conduction band offset (CBO+ = 0.29) and valence band offset (VBO+ = 0.09) assure a “spike-type” band alignment at both interfaces. This choice lowers the unwanted interfacial recombination mechanism, resulting in a challenging PCE. In addition, the impact of the work function of back contact is also investigated. According to simulation findings, Ni back electrodes with a work function of 5.04 eV is appropriate for Zn0.8Mg0.2O/(FAPbI3)0.85(MAPbB3)0.15/Cu2O perovskite solar cell. The optimized FTO/MgZnO/(FAPbI3)0.85(MAPbBr3)0.15/Cu2O/Ni PSC reaches a conversion efficiency as high as 25.86%. These findings will pave the way for the design of low-cost, high-efficiency solar cells.

27 citations



Journal ArticleDOI
TL;DR: Based on a variable-boostable chaotic system, a conservative chaotic system with controllable amplitude and offset is proposed in this paper , which exhibits rich symmetrical dynamics under different parameters and initial conditions.
Abstract: Based on a variable-boostable chaotic system, a conservative chaotic system with controllable amplitude and offset is proposed. The system exhibits rich symmetrical dynamics under different parameters and initial conditions. More interestingly, a parameter of memristor poses a partial amplitude control to a system variable. Furthermore, the derived memristive system has the property of offset boosting, where an independent constant can be introduced for free rescaling of the average value of a system variable. Experimental circuit with a memristor rheostat is designed for amplitude control. Circuit simulation based on Multisim software agrees well with the systematic analysis and numerical exploration. To the best of our knowledge, in the literature there is no 3D conservative memristive system reported with such properties as amplitude control and offset boosting.

25 citations


Journal ArticleDOI
TL;DR: In this article , a computable general equilibrium model was used to incorporate the co-benefits of carbon abatement policies into the carbon marginal abaton cost curves (MACCs), and evaluated the total abaton costs and cost saving effects for China and India to achieve their Nationally Determined Contributions (NDC) target.

25 citations


Journal ArticleDOI
TL;DR: A new rotor configuration for V-shaped interior permanent magnet machine to reduce torque ripple and electromagnetic vibration is presented and comprehensive models using coupled multiphysic fields are established and the comparative study of electromagnetic vibration aspects are done.
Abstract: This article presents a new rotor configuration for V-shaped interior permanent magnet machine to reduce torque ripple and electromagnetic vibration. The proposed rotor structure consists of two segments staggered mechanically 180°. In each segment, the intersection angle between two magnets of one V-shaped pole is different to the others, resulting in a different pole arc to pole pitch ratio. The dimensions and total volumes of magnets keep unchanged. Benefitting from the two opposing segments, unbalanced magnetic pull can be offset. Machine performances in terms of back-EMF, d -& q -axis inductance, radial and axial force and instantaneous torque ripple are intensively compared and evaluated to the conventional machine with skewing slots, which is often used in mass production. Comprehensive models using coupled multiphysic fields are established and the comparative study of electromagnetic vibration aspects are done. Two machines, i.e., the proposed machine and the conventional machine with slot skewing are prototyped. Extensive experiments are carried out and compared in terms of back-EMF, current, modal frequency, static average torque, instantaneous torque, and efficiency.

24 citations


Journal ArticleDOI
TL;DR: In this paper , a new memristive chaotic Sprott B system with a bias term has been proposed, which can adjust the symmetry of the proposed model, inducing both homogeneous and heterogeneous behaviors.
Abstract: This work proposes and investigates the dynamic behavior of a new memristive chaotic Sprott B system. One of the interesting features of this system is that it has a bias term that can adjust the symmetry of the proposed model, inducing both homogeneous and heterogeneous behaviors. Indeed, the introduced memristive system can turn from rotational symmetry (RS) to rotational symmetry broken (RSB) system in the presence or the absence of this bias term. In the RS system (i.e., absence of the bias term), pairs of symmetric attractors are formed, and the scenario of attractor merging is observed. Coexisting symmetric attractors and bifurcations with up to four solutions are perfectly investigated. In the RSB system (i.e., the bias term is non-zero), many interesting phenomena are demonstrated, including asymmetric attractors, coexisting asymmetric bifurcations, various types of coexisting asymmetric solutions, and period-doubling transition to chaos. We perfectly demonstrate that the new asymmetric/symmetric memristive system exhibits the exciting phenomenon of partial amplitude control (PAC) and offset boosting. Also, we show how it is possible to control the amplitude and the offset of the chaotic signals generated for some technological exploitation. Finally, coexisting solutions (i.e., multistability) found in the novel memristive system are further controlled based on a linear augmentation (LA) scheme. Our numerical findings demonstrated the effectiveness of the control technic through interior crisis, reverse period-doubling scenario, and symmetry restoring crisis. The coupled memristive system remains stable with its unique survived periodic attractor for higher values of the coupling strength.

Journal ArticleDOI
01 Oct 2022
TL;DR: In this paper , a hybrid ellipse fitting (EF)-based segmentation method was proposed for detecting various hematological disorders, which is a computationally efficient approach since it combines noniterative-geometric and algebraic methods.
Abstract: The automatic segmentation of blood cells for detecting hematological disorders is a crucial job. It has a vital role in diagnosis, treatment planning, and output evaluation. The existing methods suffer from the issues like noise, improper seed-point detection, and oversegmentation problems, which are solved here using a Laplacian-of-Gaussian (LoG)-based modified highboosting operation, bounded opening followed by fast radial symmetry (BOFRS)-based seed-point detection, and hybrid ellipse fitting (EF), respectively. This article proposes a novel hybrid EF-based blood-cell segmentation approach, which may be used for detecting various hematological disorders. Our prime contributions are: 1) more accurate seed-point detection based on BO-FRS; 2) a novel least-squares (LS)-based geometric EF approach; and 3) an improved segmentation performance by employing a hybridized version of geometric and algebraic EF techniques retaining the benefits of both approaches. It is a computationally efficient approach since it hybridizes noniterative-geometric and algebraic methods. Moreover, we propose to estimate the minor and major axes based on the residue and residue offset factors. The residue offset parameter, proposed here, yields more accurate segmentation with proper EF. Our method is compared with the state-of-the-art methods. It outperforms the existing EF techniques in terms of dice similarity, Jaccard score, precision, and F1 score. It may be useful for other medical and cybernetics applications.

Journal ArticleDOI
TL;DR: Wang et al. as discussed by the authors proposed an adaptive quantization parameter offset (AQPO) algorithm at both picture-level and groups of pictures (GoP)-level to adjust quantization parameters adaptively on top of the preassigned ones.
Abstract: Chinese second generation of the Audio Video Coding Standard, known as the AVS2, competing with HEVC/H.265 and AV1, has become a well-known video compression standard. Many unique tools have been developed and incorporated in AVS2. This paper proposes several encoder optimization schemes with respect to rate-distortion optimization (RDO). Specifically, by exploiting the close relationship between the total number of referenced pictures and the hierarchy of reference structure, a reference structure determined parameter (RSDP) algorithm reallocates Lagrange multiplier. Moreover, an adaptive quantization parameter offset (AQPO) algorithm is provided at both picture-level and Groups of Pictures (GoP)-level to adjust quantization parameters adaptively on top of the preassigned ones. Both RSDP algorithm and AQPO algorithm have already been adopted by AVS2 and incorporated in its reference software. Experimental results show that in the low-delay, RSDP and AQPO achieved savings of 1.35% and 1.26% on BDBR, respectively.

Journal ArticleDOI
TL;DR: In this paper , a C++ offset-free model predictive control (OF-MPC) solver is proposed to solve the longitudinal and lateral coupling control problem directly, which achieves better tracking accuracy and high-speed stability due to consideration of the tire friction circle constraints.

Journal ArticleDOI
TL;DR: In this paper , the authors analyzed the dynamical evolution of a three-dimensional symmetric oscillator with a fractional Caputo operator, and the existence results and uniqueness of solutions for the suggested model are analyzed using tools from fixed point theory.
Abstract: This article analyzes the dynamical evolution of a three-dimensional symmetric oscillator with a fractional Caputo operator. The dynamical properties of the considered model such as equilibria and its stability are also presented. The existence results and uniqueness of solutions for the suggested model are analyzed using the tools from fixed point theory. The symmetric oscillator is analyzed numerically and graphically with various fractional orders. It is observed that the fractional operator has a significant impact on the evolution of the oscillator dynamics showing that the system has a limit-cycle attractor. Offset-boosting control phenomena in the system are also studied with different orders and parameters.

Journal ArticleDOI
TL;DR: Wang et al. as discussed by the authors proposed an adaptive quantization parameter offset (AQPO) algorithm at both picture-level and groups of pictures (GoP)-level to adjust quantization parameters adaptively on top of the preassigned ones.
Abstract: Chinese second generation of the Audio Video Coding Standard, known as the AVS2, competing with HEVC/H.265 and AV1, has become a well-known video compression standard. Many unique tools have been developed and incorporated in AVS2. This paper proposes several encoder optimization schemes with respect to rate-distortion optimization (RDO). Specifically, by exploiting the close relationship between the total number of referenced pictures and the hierarchy of reference structure, a reference structure determined parameter (RSDP) algorithm reallocates Lagrange multiplier. Moreover, an adaptive quantization parameter offset (AQPO) algorithm is provided at both picture-level and Groups of Pictures (GoP)-level to adjust quantization parameters adaptively on top of the preassigned ones. Both RSDP algorithm and AQPO algorithm have already been adopted by AVS2 and incorporated in its reference software. Experimental results show that in the low-delay, RSDP and AQPO achieved savings of 1.35% and 1.26% on BDBR, respectively.

Journal ArticleDOI
TL;DR: In this paper , the authors explore the robustness of GF Offset to assumption violations, and its relationship to measures of fitness, using SLiM simulations with explicit genome architecture and a spatial metapopulation.
Abstract: Gradient Forest (GF) is a machine learning algorithm designed to analyze spatial patterns of biodiversity as a function of environmental gradients. An offset measure between the GF-predicted environmental association of adapted alleles and a new environment (GF Offset) is increasingly being used to predict the loss of environmentally adapted alleles under rapid environmental change, but remains mostly untested for this purpose. Here, we explore the robustness of GF Offset to assumption violations, and its relationship to measures of fitness, using SLiM simulations with explicit genome architecture and a spatial metapopulation. We evaluate measures of GF Offset in: (1) a neutral model with no environmental adaptation; (2) a monogenic "population genetic" model with a single environmentally adapted locus; and (3) a polygenic "quantitative genetic" model with two adaptive traits, each adapting to a different environment. We found GF Offset to be broadly correlated with fitness offsets under both single locus and polygenic architectures. However, neutral demography, genomic architecture, and the nature of the adaptive environment can all confound relationships between GF Offset and fitness. GF Offset is a promising tool, but it is important to understand its limitations and underlying assumptions, especially when used in the context of predicting maladaptation.

Journal ArticleDOI
TL;DR: In this article , an asymmetric memristive diode-bridge (AMD) emulator was proposed by inserting a DC-offset into one bridge arm of the memory device and the authors investigated the DC-offset induced asymmetric voltage-current locus.
Abstract: Asymmetric voltage-current locus is an essential property of a physical memristor when applying a bipolar periodic stimulus. To emulate this asymmetric property, this paper presents an asymmetric memristive diode-bridge (AMD) emulator by inserting a DC-offset into one bridge arm of the memristive diode-bridge. The mathematic model of the AMD emulator is derived and the DC-offset induced asymmetric voltage-current loci are studied. Furthermore, this paper proposes an AMD-based Shinriki oscillator by introducing the AMD emulator into the Shinriki oscillator and investigates the DC-offset induced kinetic behaviors using several numerical analysis methods. The AMD-based Shinriki oscillator has three fixed equilibrium points, consisting of one unstable index-1 saddle-focus and two unstable asymmetric index-2 saddle-foci. Due to the introduction of the DC-offset, the symmetry of the two unstable index-2 saddle-foci equilibrium points is broken, leading to the emergence of complex asymmetric kinetic behaviors with multi-stability in the AMD-based Shinriki oscillator. Finally, a hardware circuit is developed and its experimental results are captured to verify the numerical analysis results.

Journal ArticleDOI
TL;DR: In this paper , the authors established the equivalent relationship between the nearest-three virtual space vector and carrier-based pulsewidth-modulation scheme based on space vector coordinate for a three-level neutral-point-clamped (3L-NPC) converter.
Abstract: In this article, the equivalent relationship between the nearest-three-virtual space vector and carrier-based pulsewidth-modulation scheme is established based on space vector coordinate for a three-level neutral-point-clamped (3L-NPC) converter. Moreover, to solve the neutral-point voltage imbalance problem of the studied 3L-NPC converter-fed high-speed drives, an active modulation strategy with the generalized bias-offset injection technique is proposed. Meanwhile, the excessive computational burden is significantly overcome by the fast calculation approach. The effectiveness of the proposed modulation algorithm is validated through both simulation and experimental results obtained from a 45 kW, 32 kr/min aircraft electric starter/generator prototype system.

Journal ArticleDOI
TL;DR: In this paper , a real-time realization of a continuous-control-set model predictive current controller for the two types of permanent magnet synchronous machines is presented, where the constrained optimization problem is solved online using a slack formulation of the primal-dual interior-point method.
Abstract: This article presents a real-time realization of a continuous-control-set model predictive current controller for the two types of permanent magnet synchronous machines: 1) surface-mounted permanent magnet synchronous machine (SMPMSM) and 2) interior permanent magnet synchronous machine (IPMSM). The constrained optimization problem is solved online using a slack formulation of the primal-dual interior-point method. The proposed controller is tested on a 14.5 kW SMPMSM based on the linear time-invariant (LTI) model of the machine and on a 0.5 kW IPMSM. For the latter, we present in detail how the nonlinear first-principles modeling yields the fastest possible transient as well as an offset-free steady-state performance. The experimental results were obtained at sampling times typically used in the electrical drive applications (125 and 100 $\mu$s for the two machines, respectively).

Journal ArticleDOI
TL;DR: In this article , a global continuous toolpath optimization for both solid and partial infill designs in large format additive manufacturing (LFAM) is presented, where outward contour and double offset schemes are used to generate smooth curves as the primary volume-filling paths; the remaining unfilled areas are covered by extending zigzag lines from the closest contours.
Abstract: Large format additive manufacturing (LFAM) has witnessed rapid development in recent years and facilitated digital fabrications of geometrically intricate structures. However, there has been limited research on toolpath optimization tailored for LFAM. This paper presents a novel framework to generate a globally continuous toolpath for both solid and partial infill designs in LFAM. For solid infill, outward contour and double offset schemes are used to generate smooth curves as the primary volume-filling paths; the remaining unfilled areas are covered by extending zigzag lines from the closest contours. Subsequently, a contour layer-wise connection is carried out based on the depth-first-search algorithm to formulate a globally continuous path. A post-processing step is also presented to optimize the coverage and curvature of the toolpath design. The concept is extended for partial infill settings by trimming and joining rectangular grid lines. Compared with other state-of-the-art methods in the literature, the proposed algorithm is superior in delivering better print quality, fewer sharp turns, and enhanced fabrication efficiency. Finally, two interesting experiments demonstrate how LFAM of topology optimized structures can benefit from the proposed continuous toolpath: topology optimized table printed from thermoplastic polyurethane (TPU) and topology optimized chair printed from 3D concrete printing (3DCP).

Journal ArticleDOI
TL;DR: In this paper , the importance of integrating an integrated riser-mooring design methodology in the optimisation of mooring variables is discussed, where the integrity of the riser is adequately represented using a Safe Operation (SAFOP) zone polar diagram.

Journal ArticleDOI
TL;DR: In this article , the authors evaluated the accuracy of PPP-B2b corrections along with real-time PPP performance for users in China and surrounding areas through B2b signal transmitted from its three geostationary earth orbit (GEO) satellites.
Abstract: BeiDou Global Navigation Satellite System (BDS-3) provides a regional Precise Point Positioning (PPP) service, called PPP-B2b, for users in China and surrounding areas through B2b signal transmitted from its three geostationary earth orbit (GEO) satellites. The information broadcasted by the B2b signal include satellite orbit corrections, satellite clock offset corrections, and differential code bias (DCB) corrections of BDS-3 satellites. In this study, the accuracies of PPP-B2b corrections along with real-time PPP performance are comprehensively evaluated referenced to precise orbit and clock products from GFZ and the precise DCB products from CAS. The result indicates that the accuracy of the BDS-3 broadcast orbit is similar to that of the PPP-B2b real-time orbit. The PPP-B2b clock offset correction improved the satellite clock offset precision of the BDS-3 broadcast ephemeris. The Signal-in-Space Range Error (SISRE) of broadcast ephemeris and PPP-B2b are calculated, which are 0.536 and 1.24 m, respectively. The large SISRE value of PPP-B2b is caused by the satellite-specified systematic bias to IGS final products. The positioning performance evaluation of real-time PPP with B2b service is carried out and compared with the real-time product provided by Wuhan University (WHU) based on the eight IGS MGEX stations in China and surrounding countries. The positioning accuracy of static positioning mode with PPP-B2b service achieved centimeter-level accuracy in the selected station, and that of kinematic positioning mode achieved decimeter-level accuracy. The availability rate of PPP-B2b corrections in the surrounding area of China, however, degrades from 88.76% to 60.91% in the selected stations. The accuracy of the PPP solution using PPP-B2b correction is better than that of using WHU real-time product within China. The positioning performance of stations located at the boundary of the PPP-B2b service area, however, is affected by the number of PPP-B2b available satellites. The positioning accuracy in kinematic positioning mode is worse than that of using WHU real-time precise product.

Journal ArticleDOI
TL;DR: BADet as mentioned in this paper proposes to represent each proposal as a node for graph construction within a given cut-off threshold, associating proposals in the form of local neighborhood graph, with boundary correlations of an object being explicitly exploited.

Journal ArticleDOI
Max Menzies1
TL;DR: In this article , the authors introduce new methods to track the offset between two multivariate time series on a continuous basis and apply this framework to COVID-19 counts on a state-by-state basis in the United States to determine the progression from cases to deaths as a function of time.
Abstract: This paper introduces new methods to track the offset between two multivariate time series on a continuous basis. We then apply this framework to COVID-19 counts on a state-by-state basis in the United States to determine the progression from cases to deaths as a function of time. Across multiple approaches, we reveal an "up-down-up" pattern in the estimated offset between reported cases and deaths as the pandemic progresses. This analysis could be used to predict imminent increased load on a healthcare system and aid the allocation of additional resources in advance.


Journal ArticleDOI
TL;DR: In this paper , the effects of H 2 NG on technical, economic and environmental parameters of hybrid energy systems for building refurbishment were analyzed and compared with the separate generation for the existing plants replacement.

Journal ArticleDOI
TL;DR: This letter considers impairments such as carrier frequency offset (CFO), direct current (DC) offset and in-phase and quadrature (IQ) imbalance at the transmitter and receiver for cyclic prefix (CP) OTFS system and derives the input-output (I/O) relation in the delay-Doppler (DD) domain under these impairments.
Abstract: Orthogonal time frequency space (OTFS) waveform, which is robust to doubly-selective fading channels is a strong contender for the Fifth generation (5G) communications. At high frequencies, hardware imperfections are prominent in practice at the transceivers. In this letter, we consider impairments such as carrier frequency offset (CFO), direct current (DC) offset and in-phase and quadrature (IQ) imbalance at the transmitter (Tx) and receiver (Rx) for cyclic prefix (CP) OTFS system. We derive the input-output (I/O) relation in the delay-Doppler (DD) domain under these impairments and show that due to the DC offset and IQ imbalance, image Doppler interference (IDI) appears along the Doppler domain and the CFO becomes part of the channel parameters. We estimate impairment parameters in the DD domain and compensate these at Tx and Rx in the time domain. The normalized mean square error (NMSE) of the estimated imbalance parameters are evaluated and it is observed that NMSE reduces with increase in, pilot power, number of Doppler bins and with windowing techniques applied in time-frequency (TF) domain.

Journal ArticleDOI
TL;DR: In this paper , the authors investigate the impact of the COVID-19 pandemic on German household income in 2020 using a micro-level approach, combining a microsimulation model with novel labour market transition techniques.
Abstract: In this paper, we investigate the impact of the COVID-19 pandemic on German household income in 2020 using a micro-level approach. We combine a microsimulation model with novel labour market transition techniques to simulate the COVID-19 shock on the German labour market. We find the consequences of the labour market shock to be highly regressive with a strong impact on the poorest households. However, this effect is nearly entirely offset by automatic stabilisers and discretionary policy measures. We explore the cushioning effect of these policies in detail, showing that short-time working schemes and especially the one-off payments for children are effective in cushioning the income loss of the poor.

Journal ArticleDOI
TL;DR: In this paper , a solar photovoltaic distribution static compensator (SPV-DSTATCOM) under partial shading condition (PSC) is studied using a single-stage, 3-phase grid-connected mode.
Abstract: A solar photovoltaic distribution static compensator (SPV-DSTATCOM) under partial shading condition (PSC) is studied using a single-stage, 3-phase grid-connected mode. Under PSC, the performance of the grid-connected SPV-DSTATCOM is studied and addressed the issues such as active current sharing, reactive power control, and harmonic elimination. Rejection of DC offset with such PSC condition is an issue when using a conventional Proportional Resonant (PR) controller. As a result of this research, a new and improved PR (IPR) based second-order generalized integrator (SOGI) has been developed that has unity gain at the fundamental frequency and greater DC offset rejection capability to address the PR controller shortcomings. The proposed controller’s performance is evaluated in both steady-state and dynamic conditions with varying loads and different PSC conditions. An experimental evaluation of the proposed controller’s design assumptions is also presented in the form of a comparison with both the PR controller and the adaptive PR controller.