Input Phase Research Articles

Adaptive leakage signal cancellation algorithm in heterodyne FMCW system

To mitigate the leakage signal that obstructs the target information extraction in miniatured frequency modulated continuous wave (FMCW) radar system, an adaptive leakage signal cancellation algorithm is proposed in this paper. Without any help of the additional auxiliary path, all the processing for the intermediate frequency (IF) signal can be conducted in the digital domain. The basic principle to cancel leakage signal is to produce a cancelling signal, which has the same amplitude and anti-phase with the leakage signal. Differently, in this paper, the input phase parameter of the proposed method can be arbitrary and it can be modified by the corresponding corrected function. Besides, to acquire the phase noise in the leakage signal conveniently when generating cancelling signal, the information geometry theory is applied to transform the complex phase noise model into statistical characteristics calculation of the input signal. The effectiveness of the model and the proposed algorithm is verified by simulated results. Furthermore, a real FMCW system is designed to collect the practice echo signals. The resulting data denotes that the leakage signal in the received signal is greatly suppressed and the leakage signal power drops by −15.92 dB.

THE EXPERIMENTAL STUDY IN THE CLASSROOM FOR THE ESTABLISHMENT OF THE ACCOUNTING STUDENTS’ SOFT SKILL THROUGH EFFECTIVE TEAM BUILDING

An accounting education graduate is required to master hard skills and soft skills. In terms of mastering soft skills in the accounting profession, it means to work together as a team. This soft skill provision is obtained through effective learning methods by forming a team that is given the assignment to solve a problem and accounts for it through presentations. The purpose of this study is to provide guidelines for lecturers to build effective teams for students. This study uses a descriptive experimental approach conducted by researchers in 5th semester students with Business Mixing Accounting courses. Team formation refers to McGrath’s Model framework. This model includes the input, process, and output stages. The input phase emphasizes the quality of the teams from various inputs. The larger the team, the more personality types, and time variations will be accommodated and the more conflicts that will be faced. The stage of the process includes how members deal with conflict and make conflict a success. The output stage includes criteria for measuring group performance results and other measures such as member performance satisfaction, group cohesiveness at the end of the task, and changes in member behavior to be better

Analytical Calculation of Performance of Line-Start Permanent-Magnet Synchronous Motors Based on Multidamping-Circuit Model

This article presents a new analytical method for calculating performance of line-start permanent-magnet synchronous motor (LSPMSM) based on multidamping-circuit model (MDCM) to take spatial harmonic components of LSPMSM into account. First, MDCM of damping bar in the rotor is established according to Kirchhoff's current law. Second, an eleven-order system of LSPMSM is deduced from a group of differential equations according to the equations of flux linkage, voltage, torque, and motion. Then, starting process of LSPMSM is simulated with the proposed analytical method, including speed, current, and electromagnetic torque waveforms versus time, respectively. The starting performance and synchronization capability are analyzed and compared under different effective value of input phase voltage, moment of inertia, and load torque. The simulation time with finite element method is about 1235 times longer than the simulation time with the proposed analytical method to calculate the starting process of LSPMSM with the same computer. Finally, the validation of the developed analytical method based on MDCM is verified by comparing simulating results with experimental results and direct axis and quadrature axis (DQ) model. The results based on this new method are reliable. It is conducive to calculate, analyze, and design LSPMSM with less time.

Interferometric measurement of complex-field changes in transient detection imaging.

We report an experimental method that combines nonlinear-crystal-based transient detection imaging (TDI) with interferometric complex-field retrieval. The system allows measuring both phase and amplitude of a dynamic scene while suppressing stationary background. Theoretical and experimental results prove the linear relation existing between input and output phases, as well as the benefits of phase analysis for both detection and measurement with high resolutions of λ/30, even under noisy conditions. Additionally, we present experimental evidence of the remarkable ability of the technique to detect phase sign changes in the scene -what we call differential-phase TDI- showing great detection sensitivity and no calibration requirements.

An Adaptive Feed-Forward Phase Locked Loop for Grid Synchronization of Renewable Energy Systems under Wide Frequency Deviations

Synchronization is a crucial problem in the grid-connected inverter’s control and operation. A phase-locked loop (PLL) is a typical grid synchronization strategy, which ought to have a high resistance to power system uncertainties since its sensitivity influences the generated reference signal. The traditional PLL catches the phase and frequency of the input signal via the feedback loop filter (LF). In general, to enhance the steady-state capability during distorted grid conditions generally, a filter tuned for nominal frequency is used. This PLL corrects large frequency deviations around the nominal frequency, which increases the PLL’s locking time. Therefore, this paper presents an adaptive feed-forward PLL, where the input signal frequency and phase under large frequency deviations are tracked precisely, which overcomes the above-mentioned limitations. The proposed adaptive PLL consists of a feedback loop that reduces the phase error. The feed-forward loop predicts the frequency and phase error, and the frequency adaptive FIR filter reduces the ripples in output, which is due to input distortions. The adaptive mechanism adjusts the gain of the filter in accordance with the supply frequency. This reduces the phase and frequency error and also decreases the locking time under wide frequency deviations. To verify the effectiveness of the proposed adaptive feed-forward PLL, the system was tested under different grid abnormal conditions. Further, the stability analysis has been carried out via a developed prototype test platform in the laboratory. To bring the proposed simulations into real-time implementations and for control strategies, an Altera Cyclone II field-programmable gate array (FPGA) board has been used. The obtained results of the proposed PLL via simulations and hardware are compared with conventional techniques, and it indicates the superiority of the proposed method. The proposed PLL effectively able to tackle the different grid uncertainties, which can be observed from the results presented in the result section.

Multiplexing the aperture of a metasurface: inverse design via deep-learning-forward genetic algorithm

The modern design of advanced functional materials or surfaces has increasingly undergone miniaturization and integration, so as to implement multiple functions using the same aperture. Metasurfaces, as an emerging kind of artificial functional surface, have provided unprecedented freedom in manipulating electomagnetic (EM) waves upon two-dimensional surfaces. It is desirable that the aperture of metasurfaces can be multiplexed with a number of functions for EM waves. Based on previous research, an artificial neural network-forward design can achieve an inverse design. In this paper, we propose an inverse design method of multiplexing metasurface apertures. A deep learning network (DLN) is trained to serve as a forward model for a genetic algorithm (GA), that is, a deep-leaning-forward genetic algorithm (DLF-GA). With the DLF-GA model, the phase of meta-atoms can be predicted for orthogonally linearly polarized waves simultaneously. The DLN was trained by a data set consisting of 70 000 samples with an accuracy of 95% on the test data. To demonstrate the competency of this method, we demonstrate the design of a multiplexed metasurface that can achieve focusing and diffuse scattering for polarization. The metasurface, which consists of 24 × 24 meta-atoms, can be generated monolithically with the input phase profile. A prototype was fabricated and measured. The predicted, simulated, and measured results are well consistent and underscore the validity of this inverse design method. This method provides an efficient and accurate method for the fast design of multiplexed metasurfaces and will find applications in microwave engineering such as in satellite communications.

Reconfigurable structured light generation in a multicore fibre amplifier

Structured light, with spatially varying phase or polarization distributions, has given rise to many novel applications in fields ranging from optical communication to laser-based material processing. However the efficient and flexible generation of such beams from a compact laser source at practical output powers still remains a great challenge. Here we describe an approach capable of addressing this need based on the coherent combination of multiple tailored Gaussian beams emitted from a multicore fibre (MCF) amplifier. We report a proof-of-concept structured light generation experiment, using a cladding-pumped 7-core MCF amplifier as an integrated parallel amplifier array and a spatial light modulator (SLM) to actively control the amplitude, polarization and phase of the signal light input to each fibre core. We report the successful generation of various structured light beams including high-order linearly polarized spatial fibre modes, cylindrical vector (CV) beams and helical phase front optical vortex (OV) beams.

Macroplastic Storage and Remobilization in Rivers

The paper presents a conceptual model of the route of macroplastic debris (>5 mm) through a fluvial system, which can support future works on the overlooked processes of macroplastic storage and remobilization in rivers. We divided the macroplastic route into (1) input, (2) transport, (3) storage, (4) remobilization and (5) output phases. Phase 1 is mainly controlled by humans, phases 2–4 by fluvial processes, and phase 5 by both types of controls. We hypothesize that the natural characteristics of fluvial systems and their modification by dam reservoirs and flood embankments construction are key controls on macroplastic storage and remobilization in rivers. The zone of macroplastic storage can be defined as a river floodplain inundated since the beginning of widespread disposal of plastic waste to the environment in the 1960s and the remobilization zone as a part of the storage zone influenced by floodwaters and bank erosion. The amount of macroplastic in both zones can be estimated using data on the abundance of surface- and subsurface-stored macroplastic and the lateral and vertical extent of the zones. Our model creates the framework for estimation of how much plastic has accumulated in rivers and will be present in future riverscapes.

Utilizing phase delays of an integrated pixel-array structure to generate orbital-angular-momentum beams with tunable orders and a broad bandwidth.

We study the relationship between the input phase delays and the output mode orders when using a pixel-array structure fed by multiple single-mode waveguides for tunable orbital-angular-momentum (OAM) beam generation. As an emitter of a free-space OAM beam, the designed structure introduces a transformation function that shapes and coherently combines multiple (e.g., four) equal-amplitude inputs, with the kth input carrying a phase delay of (k-1)Δφ. The simulation results show that (1) the generated OAM order ℓ is dependent on the relative phase delay Δφ; (2) the transformation function can be tailored by engineering the structure to support different tunable ranges (e.g., l={-1},{-1,+1},{-1,0,+1}, or {-2,-1,+1,+2}); and (3) multiple independent coaxial OAM beams can be generated by simultaneously feeding the structure with multiple independent beams, such that each beam has its own Δφ value for the four inputs. Moreover, there is a trade-off between the tunable range and the mode purity, bandwidth, and crosstalk, such that the increase of the tunable range leads to (a) decreased mode purity (from 91% to 75% for l=-1), (b) decreased 3 dB bandwidth of emission efficiency (from 285 nm for l={-1} to 122 nm for l={-2,-1,+1,+2}), and (c) increased crosstalk within the C-band (from -23.7 to -13.2dB when the tunable range increases from 2 to 4).

Actor neural networks for the robust control of partially measured nonlinear systems showcased for image propagation through diffuse media

The output of physical systems, such as the scrambled pattern formed by shining the spot of a laser pointer through fog, is often easily accessible by direct measurements. However, selection of the input of such a system to obtain a desired output is difficult, because it is an ill-posed problem; that is, there are multiple inputs yielding the same output. Information transmission through scattering media is an example of this problem. Machine learning approaches for imaging have been implemented very successfully in photonics to recover the original input phase and amplitude objects of the scattering system from the distorted intensity diffraction pattern outputs. However, controlling the output of such a system, without having examples of inputs that can produce outputs in the class of the output objects the user wants to produce, is a challenging problem. Here, we propose an online learning approach for the projection of arbitrary shapes through a multimode fibre when a sample of intensity-only measurements is taken at the output. This projection system is nonlinear, because the intensity, not the complex amplitude, is detected. We show an image projection fidelity as high as ~90%, which is on par with the gold-standard methods that characterize the system fully by phase and amplitude measurements. The generality and simplicity of the proposed approach could potentially provide a new way of target-oriented control in real-world applications when only partial measurements are available. Machine learning has become popular in solving complex optical problems such as recovering the input phase and amplitude for a specific pattern or image measured through a scattering medium. In a more challenging application, Rahmani et al. consider the problem of also producing desired outputs for such a nonlinear system when only some intensity-only measurements of example outputs are available. They develop a neural network approach that can ensure the transmission of images through a highly nonlinear system—a multimode fibre—with a 90% fidelity.

The quick death of a lake: human impact on Lake Tresssee (N Germany) during the last 6000 years – an approach using pollen, Cladocera and sedimentology

Human-induced fluctuation of lake levels has been a common phenomenon in Europe since Neolithic times. At present, Lake Tresssee is a eutrophic lake covering less than 5 ha in northern Germany, but its sudden shrinking from ~125 ha before 1800 is considered a consequence of anthropogenic lowering of the lake level. We investigated the history of anthropogenic vegetation changes and water level fluctuations by multiproxy studies of a 4 m core from the former lake area. Our analyses of pollen and Cladocera subfossil, chemistry and sedimentological features yielded important conclusions about interactions between land-use history and climate impacts on the lake and its surroundings. The results indicate that the highest lake level persisted until the Late Atlantic. Since the Subboreal there have been several fluctuations, mostly in consequence of climate impacts. Later, different phases of sediment input to the lake from tributary streams and probably also from aeolian processes from an adjacent dune field were observed. At ~2800 BC the sedimentation rate decreased in consequence of fluvial impacts, as the lake basin was nearly filled up with deposits. As a result of greater human impacts, from the Early Bronze Age the macrophyte zone expanded in the lake, the oxygen content of the water continuously decreased, and heathlands developed in the surroundings. From the Late Iron Age and in the Early Medieval, pollutants probably from ironworks are detectable by geochemical analyses in the corresponding segments. In the pollen diagram the Migration Period is clearly visible, but the suggested radiocarbon date is younger than in Lake Belau in the neighboring region of Schleswig-Holstein. Most probably our pollen diagram did not register the absolute maximum values of Fagus related to the Migration Period. From the Early Medieval a clear phase of resettlement occurs. Since the Early Modern period, the lake level has shrunk rapidly in consequence of historically documented human activity.

Rating Faculty for Foreign Student in Egypt by Bloom Filter Classifier and Collaborative Filtering

This paper presents an approach of bloom filter classifier and collaborative filtering to help foreign student to choose the suitable faculty according to his nationality and number of years that need to study. Our approach consist of three phases are: input phase, classification phase, and recommendation phase. In Input phase, the student enters the nationality and number of suggested years study. In classification phase, the approach classifies the student according to input data based on bloom filter classifier. In recommendation phase, the approach recommended the top five faculty if exists based on collaborative filtering technique (CF). Our dataset collected from Misr University for Science and Technology (MUST) and the results of our approach suitable and has a good manner for the student with accuracy 90%.

Observation of four Fermi-Pasta-Ulam-Tsingou recurrences in an ultra-low-loss optical fiber.

We report the experimental observation of more than four Fermi-Pasta-Ulam-Tsingou recurrences in an optical fiber thanks to an ultra-low loss optical fiber and to an active loss compensation system. We observe both regular (in-phase) and symmetry-broken (phase-shifted) recurrences, triggered by the input phase. Experimental results are confirmed by numerical simulations.

Design of threshold voltage insensitive pixel driver circuitry using a-IGZO TFT for AMOLED displays

This work proposes a novel amorphous-indium-gallium-zinc-oxide thin film transistor (a-IGZO TFT) based pixel driver circuitry to compensate for threshold voltage variations of TFTs and OLED current degradations for AMOLED (Active Matrix Organic Light-Emitting Diodes) displays. The proposed circuit uses a three-phase clocking scheme i.e. threshold voltage detection phase, data input phase and emission phase for compensating threshold voltage variations. The circuit has been simulated and verified with cadence spectre using a-IGZO TFT and OLED SPICE models. The proposed circuit is able to maintain the OLED current with a maximum error of 0.68% when the threshold voltage is varied from −3.5 ​V to 3.5 ​V.

Identification, classification and shortlisting of performance indicators for hospital facilities management

PurposeThis paper aims to report on a study that aims to establish a list of systematically classified key performance indicators (KPIs) that are useful for hospital facilities management (FM).Design/methodology/approachA review of literature was conducted to identify indicators that are applicable to hospital FM. Each indicator was classified using a phase–hierarchy (P-H) model, which is a two-dimensional matrix comprising three phases (input, process and output) of facilities services delivery and three hierarchical FM levels (operational, tactical and strategic). The classified indicators were further shortlisted via a focus group study.FindingsFrom the literature review, 61 indicators were identified as applicable to hospital FM. Most of the indicators, according to the P-H model, are for evaluating the FM input or output phase, at the strategic or tactical level. Further refinement and shortlisting of the indicators by the focus group experts resulted in 18 KPIs, which fall into 4 aspects: “physical”, “safety”, “environmental” and “financial”.Research limitations/implicationsThe study illustrates that the P-H model is useful for classifying the performance indicators systematically along the two fundamental FM dimensions – phase and hierarchy. Further research may use this model to classify performance indicators in other contexts.Practical implicationsThe method of this study can be adapted for use in identifying, classifying and shortlisting FM performance indicators for other types of buildings. The shortlisted KPIs can be used for assessing the FM performance of hospitals.Originality/valueTo the best of the authors’ knowledge, this study is the first of its kind that used the P-H model to classify hospital FM performance indicators.

Chiral Magnonics: Reprogrammable Nanoscale Spin Wave Networks Based on Chiral Domain Walls.

SummarySpin waves offer promising perspectives as information carriers for future computational architectures beyond conventional complementary metal-oxide-semiconductor (CMOS) technology, owing to their benefits for device minimizations and low-ohmic losses. Although plenty of magnonic devices have been proposed previously, scalable nanoscale networks based on spin waves are still missing. Here, we demonstrate a reprogrammable two-dimensional spin wave network by combining the chiral exchange spin waves and chiral domain walls. The spin-wave network can be extended to two dimensions and offers unprecedented control of exchange spin waves. Each cell in the network can excite, transmit, and detect spin waves independently in the chiral domain wall, and spin-wave logics are also demonstrated. Our results open up perspectives for integrating spin waves into future logic and computing circuits and networks.

Investigation of automatic electric drives balancing transformers with lead control angles

Analysis were carried out of power rectifiers’ commutation in balancing transformers at lead control angles, positive effect of shielding angle against surge voltage on the equipment main performance indicators was established, equations and experimental characteristics of this component operation were provided. As a result of theoretical and experimental investigations of the surge protection device operation, a significant positive effect on the quality of switching power rectifiers in the balancing transformer in case of lead control angles was detected. The relationship between the degree of reduction of overvoltage in the input phase voltage of the converter and the capacitance values of the capacitor, the angle of the first switching stage and the lead control angle of the converter were determined. A further study of the unit operation is to establish practically applicable quantitative relations between the specified values.

Using Brain Science Theory to Analyze the Unity between Language Input and Output: Methodology Improvement Substantiation

Introduction. Based on the brain science theory of “how people learn” and in order to modernize the methodology of psycholinguistic research, this research used documentary analysis and addressed the standpoint that the 4MAT Teaching and Learning Model can be subsumed into or superimposed on the Kirkpatrick Four-Level Evaluation Model, and vice versa. Meanwhile, the phase of language input and output is analyzed on the basis of the two Models above. In the end, some implications arise so as to provide reference for prospective researchers and practitioners in psycholinguistics.
 The aim of the study. The 4MAT Teaching and Learning Model and the Kirkpatrick Four-Level Evaluation Model are both widely applied, so a deliberate literature review to clarify the integration and the unity between them is conducted that expects to make some theoretical references inspired by the unity available to a wide range of linguistic teaching design and learning performance evaluation.
 The authors argue that the references interconnect teaching design and learning performance evaluation in light of language input and output and therefore help linguistic teachers/trainers with a whole and valid scheme at the very beginning of student learning, and this is the unity that also corresponds to Kirkpatrick & Kirkpatrick’s standpoint: “The end is the beginning”.
 Research methods. The study was conducted using the semantic differential scaling and the method of documentary analysis.
 Results. A combination of brain science theory and Fractal Information Theory has verified initially how the 4MAT Teaching and Learning Model and the Kirkpatrick Four-Level Evaluation Model subsume and superimpose in terms of the theoretical framework, i.e., the unity between a teaching theory and a learning performance evaluation theory. Such integration not only originates from the inherent unity verified by a thoughtful literature review but also receives theoretical support from interdisciplinary studies. Meanwhile, this integration is intertwined with language input and output in a psycholinguistic/neurolinguistic manner.
 Conclusions. A primary investigation using brain science theory and other theories to analyze the integration between the 4MAT Teaching and Learning Model and the Kirkpatrick Four-Level Evaluation Model shows the unity between both models. This investigation led to achieving the purpose of the study: modernizing the methodology of psycholinguistic research. With implementing the components/stages of language input and output as this article proposed, it is expected to be promising in extending and applying both models theoretically and practically in linguistics and other relevant areas in the future. As it comes to studies, it is recommended that the two Models be connected to analyze more teaching models and/or learning performance evaluation models for unity, inquire performance evaluation in collaborations with scenarios in practice, or even associate other disciplines under the implementation of Fractal Information Theory. A possible suggestion for psycholinguistic researchers is to design curricular and lessons based on the Unified Models (Figure 1 & 2) proposed in this study and evaluate instructional efficacy and student learning performance. Another potential research direction is to use each quadrant of the Unified Models and analyze related components in more specific language input and output phases: listening, reading, speaking, writing, and even smaller components in the four types of language skills. As it comes to practice, especially in psycholinguistics and/or other relevant disciplines, the key to apply the two target Models simultaneously depends on how to regulate respective quadrants/levels pro rata as well as the wholeness between them to simultaneously achieve “dynamic equilibrium” in the 4MAT Teaching and Learning Model and “The end is the beginning” in the Kirkpatrick Four-Level Evaluation Model.

Putative Sympathetic Oscillator in the Thoracic Spinal Cord of the Bullfrog

BACKGROUNDCardiorespiratory control is essential for survival of all vertebrates, yet our understanding of the neuronal circuitry involved is rudimentary ‐‐ in part because there is little data beyond mammals to guide us. Neuronal oscillators are discrete neural circuits located within the central nervous system that are capable of generating rhythmic outputs without phasic input. These circuits are found throughout the animal kingdom and are often critical for regulating overt rhythmic behaviours such breathing. Previously, we found three oscillators in the frog brainstem that control ventilation: one for buccal ventilation, two for lung. Three respiratory oscillators have subsequently been found in mammals. Central neuronal oscillators within the sympathetic nervous system of frogs and mammals have also been suspected, but these oscillators have yet to be precisely located.FINDINGSUsing extracellular recording and transection techniques in the frog superfused, isolated brainstem and spinal cord preparation, we discovered a robust, yet previously unreported buccal‐like rhythm in the third spinal nerve (SNIII). Unlike the ventilatory rhythms we normally study, the SNIII rhythm demonstrates poor bilateral synchrony. Our data also suggest that this rhythm is: (a) not coupled to ventilatory rhythms recorded in cranial nerves; (b) has distinct responses to pharmacological stimulation compared to ventilatory rhythms; (c) does not require the brainstem; and (d) persists in a chunk of spinal cord centered around SNIII. These data suggest an additional neuronal oscillator in the frog spinal cord located at the level of SNIII. However, removing the brainstem alters the frequency, increases variability and degrades left‐right synchrony of the rhythm, suggesting brainstem connections are important for normal function.SIGNIFICANCEThe literature has long debated the existence of central neuronal oscillators that modulate sympathetic nervous system activity in vertebrates. We propose that the bursting activity recorded from the SNIII in frog is the output of such an oscillator, discovery of which could prove critical in shaping our current understanding of the function and evolution of the sympathetic nervous system.Support or Funding InformationNSERC and HBI.

Time-resolved characterization of a free plasma jet formed off the surface of a piezoelectric crystal

When a piezoelectric transformer (PT) is actuated by a low input voltage (∼10 V), electromechanical coupling leads to a very high (∼103 V) surface potential at the distal end that can ionize the surrounding gas and lead to a plasma jet emanating from the surface. PTs are attractive for non-equilibrium plasma generation because of their simple operation, low required input voltage, and low power consumption. In this work, the time-resolved characteristics of the free surface plasma jet generated by a PT operating in open air have been investigated. The temporal evolution of the PT-driven plasma was visualized by using an intensified CCD camera and plasma formation was correlated with the current behavior of the plasma jet. Notably, the plasma formation is a discrete process, appearing at a relatively fixed phase of the sinusoidal input, and the strongest plasma jet appears at the end of the positive half-cycle. Simultaneous measurements of the current show that the discharge current response is consistent with the chaotic mode for a plasma jet and appears statistically about a 1 μs earlier than plasma jet light emission, which indicates that there is a strong afterglow. With a low input voltage required for operation, these types of PT-driven plasma jets could have wide utility in emerging plasma applications beyond the laboratory, such as in healthcare and water treatment.