Sweep Operation Research Articles

High Memory Window, Dual‐Gate Amorphous InGaZnO Thin‐Film Transistor with Ferroelectric Gate Insulator

Ferroelectric (FE) hafnium zirconium oxide (HZO) thin‐film transistors (TFTs) are of increasing interest for next‐generation memory and computing applications. However, these devices face challenges in achieving a substantial memory window (MW). This report presents amorphous InGaZnO (a‐IGZO) ferroelectric–dielectric (FD), dual‐gate thin‐film transistors (DG‐TFTs) with FE‐HZO as a bottom gate insulator (GI) and SiO2 as a top GI. The ferroelectricity in HZO is confirmed through the grazing incidence X‐ray diffraction (GI‐XRD), capacitance, and polarization measurements. The FD‐DG TFT can increase the MW by tuning the threshold voltage (VTH) due to electrostatic coupling between the top gate (TG) and bottom gate (BG). The increase of MW at the TG driving is related to the coupling factor which is equal to the ratio of the equivalent capacitance of top to bottom gated transistors. During the bottom sweep, the FD‐DG‐TFT demonstrates an anticlockwise hysteresis with a MW of 4.98 V, a high ION/IOFF ratio of ≈106, and a steep subthreshold swing (SS) of 90 mV dec−1. On the contrary, MW of 12 V and SS of 140 mV dec−1 are observed for the top sweep operation. A thinner ferroelectric GI at BG TFT induces sufficient electrostatic coupling to cause a large VTH shift at TG driving, resulting in a boosted MW.

Color Image Encryption Based on an Evolutionary Codebook and Chaotic Systems.

Encryption of images is an important method that can effectively improve the security and privacy of crucial image data. Existing methods generally encrypt an image with a combination of scrambling and encoding operations. Currently, many applications require highly secure results for image encryption. New methods that can achieve improved randomness for both the scrambling and encoding processes in encryption are thus needed to further enhance the security of a cipher image. This paper proposes a new method that can securely encrypt color images. As the first step of the proposed method, a complete bit-level operation is utilized to scramble the binary bits in a color image to a full extent. For the second step, the bits in the scrambled image are processed with a sweeping operation to improve the encryption security. In the final step of encryption, a codebook that varies with evolutionary operations based on several chaotic systems is utilized to encrypt the partially encrypted image obtained in the second step. Experimental results on benchmark color images suggest that this new approach can securely encrypt color images and generate cipher images that remain secure under different types of attacks. The proposed approach is compared with several other state-of-the-art encryption approaches and the results show that it can achieve improved encryption security for cipher images. Experimental results thus suggest that this new approach can possibly be utilized practically in applications where color images need to be encrypted for content protection.

Investigation of resistive switching behaviors of cuprous phosphide thick film

In order to find high-performance memristor materials. we prepared cuprous phosphide (Cu3P) thick film by a simple chemical reaction method and studied its resistive switching properties. We investigated the effects of device structure, voltage sweep rate and electrode material on the resistive switching performance. For devices employing various electrode materials, negligible disparities were observed in transition voltage (< 0.35 V), endurance (2 ×103), and retention time (> 4 ×104 s). However, substantial differences were observed in operational speed and Off/On ratio. Specifically, device utilizing stainless steel (SS) electrode exhibited the highest operational speed (5000 V/s), while that employing nickel electrode demonstrated the largest Off/On ratio (2.1 ×104). We also observed that the device status self-healed after a voltage sweep operation. Finally, we discussed electrical switching mechanism. Our work enriches the resistive switching performance and mechanism of Cu3P bulk materials, hoping to provide a reference for the research of memristor materials.

Sources of variation in nutrient loads collected through street sweeping in the Minneapolis-St. Paul Metropolitan Area, Minnesota, USA

Excess non-point nutrient loading continues to impair urban surface waters. Because of the potential contribution of tree litterfall to nutrient pollution in stormwater, street sweeping is a promising management tool for reducing eutrophication in urban and suburban regions. However, nutrient concentrations and loads of material removed through street sweeping have not been well characterized, impeding the development of pollution reduction credits and improvement of models for stormwater management. We evaluated the role of canopy cover over streets, street sweeper type, season, and sweeping frequency in contributing to variation in concentrations and loads of nitrogen (N), phosphorus (P), and solids recovered in street sweepings, using analyses of samples collected during regular street sweeping operations in five cities in the Minneapolis-St. Paul Metropolitan Area, Minnesota, USA. We expected that nutrient concentrations and loads would be highest in seasons and places of higher tree litterfall. We also expected that regenerative-air sweepers would recover higher loads compared to mechanical broom sweepers. Total N and P concentrations in sweepings increased most strongly with canopy cover in June, October, and November. Total N and P recovered in street sweepings similarly increased with canopy cover in June, October, and November, and peaked in early summer and autumn, times of high litterfall. In contrast, total dry mass in sweepings was greatest in early spring, following winter snowmelt. However, nutrient loads and concentrations did not differ between sweeper types. Our results add to growing evidence of the importance of street trees in contributing nutrient pollution to urban surface waters. Street sweeping focused on high-canopy streets during early summer and autumn is likely an effective management tool for stormwater nutrient pollution.

E-HEALTH ARMBAND REMINDER WITH GPS TRACKER FOR STREET SWEEPER OF CENRO CALAMBA CITY, LAGUNA

This study presents the development of an E-Health Armband Reminder with a GPS tracker designed specifically for Street sweepers of CENRO Calamba City, Laguna. The objective of this project is to enhance the safety and efficiency of street sweeping operations by providing real-time monitoring and reminders to the sweepers. The E-health Armband Reminder incorporates a GPS tracker that allows supervisors to track the location of the sweepers in real-time. This feature enables efficient deployment of resources and facilitates prompt assistance in case of emergencies or accidents. Additionally, the armband serves as a reminder tool, providing alerts and notifications for hydration, Weather, and safety protocols. The system's development involved extensive research, analysis of user requirements, and collaboration with the street sweepers and CENRO Calamba City. The armband's design and functionality were optimized to suit the specific needs and constraints of the street sweeping operation. Preliminary testing of the E-Health Armband Reminder demonstrated promising results, showing improved task management as the Attendance monitoring and increased safety awareness among the street sweepers.

Evaluation and prediction of individual growth trajectories

Background Conventional growth charts offer limited guidance to track individual growth. Aim To explore new approaches to improve the evaluation and prediction of individual growth trajectories. Subjects and methods We generalise the conditional SDS gain to multiple historical measurements, using the Cole correlation model to find correlations at exact ages, the sweep operator to find regression weights and a specified longitudinal reference. We explain the various steps of the methodology and validate and demonstrate the method using empirical data from the SMOCC study with 1985 children measured during ten visits at ages 0–2 years. Results The method performs according to statistical theory. We apply the method to estimate the referral rates for a given screening policy. We visualise the child’s trajectory as an adaptive growth chart featuring two new graphical elements: amplitude (for evaluation) and flag (for prediction). The relevant calculations take about 1 millisecond per child. Conclusion Longitudinal references capture the dynamic nature of child growth. The adaptive growth chart for individual monitoring works with exact ages, corrects for regression to the mean, has a known distribution at any pair of ages and is fast. We recommend the method for evaluating and predicting individual child growth.

Directly modulated optical negative feedback lasers for long-range FMCW LiDAR.

Frequency sweep operation of directly modulated optical negative feedback lasers is numerically and experimentally investigated for frequency-modulated continuous-wave (FMCW) light detection and ranging (LiDAR) with a high signal-to-noise ratio (SNR), particularly over a long range. Low FM noise corresponding to a spectral linewidth of ∼2.0 kHz is sustained even with injection current modulation of an optical negative feedback laser through optical feedback from a Fabry-Perot etalon, and a beat note spectrum with a 30-dB SNR is achieved even when a 300-m delay fiber is used as a ranging sample. These results encourage an approach to provide directly modulated frequency-swept lasers for long-range FMCW LiDAR.

Monotonicity of the principal pivot transform

We prove that the principal pivot transform (also known as the partial inverse, sweep operator, or exchange operator in various contexts) maps matrices with positive imaginary part to matrices with positive imaginary part. We show that the principal pivot transform is matrix monotone by establishing Hermitian square representations for the imaginary part and the derivative.

Gravimetric and Number Distributions of Urban PM Residuals from Urban Maintenance Practices

AbstractParticulate matter (PM) recovery from street sweeping (SS), catch basin (CB), and unit operation (UO) is essential for sustainability of these urban hydrologic functional units (HFUs). PM i...

Deep Learning in a Robot Arm Imitating the Sweeping Operation of Brooms

Deep Learning in a Robot Arm Imitating the Sweeping Operation of Brooms

Frequency stabilization of dual-mode microchip laser by means of beat frequency stabilization

The stabilization of the laser oscillation frequency of a dual-mode microchip laser was demonstrated by stabilizing the beat frequency generated by the two simultaneously oscillating longitudinal modes. In the experiment, a beat frequency of 101 GHz was stabilized to ± 50 kHz using negative feedback control. As a result, the fluctuation of the laser oscillation frequency was finally stabilized to ± 50 MHz or less within the resolution of the measurement instrument with an estimated short-term fluctuation of ± 3.3 MHz. Furthermore, using this technique, the initial drift of the laser oscillation frequency was significantly reduced, and the linear sweep operation of the laser oscillation frequency was successfully demonstrated by linearly sweeping the beat frequency over 30 MHz while maintaining locking. Our technique is essentially robust and suitable for the miniaturization of the system in the future.

The reducibility of matrix sweeping operations: A computational issue in linear belief functions

Matrix sweeping operations are the basis for the knowledge representation and combination of linear belief functions. Yet, their basic properties are not well studied and often misunderstood. This paper attempts to fill the void and corrects a long lasting mistake in the literature on whether a block-level sweeping from a nonsingular submatrix can be reduced into sequential element-level sweepings from individual leading diagonal elements of the submatrix. It proposes a new alternative to workaround the failure of reducibility and introduces a prototype system, dubbed LMOS, in support of irreducible sweeping operations.

Reduced interfacial fluctuation leading enhanced mobility in a monolayer MoS2 DG FET under low vertical electric field

Compared to the silicon device whose performance is severely degraded due to the pin-holes and channel inactive space when the channel thickness is less than 1 nm, despite monolayer transition-metal dichalcogenides being the most stable structure to be used as a two-dimensional semiconductor material, precise analysis of the double-gate (DG) field-effect transistor (FET) device structure has hardly been performed thus far. Hence, we analyzed the device operation characteristics of single-gate and DG sweeps in a monolayer MoS2 DG FET structure, where the interfacial carrier behavior is distinguished from both gates by the different gate dielectric materials at the top and bottom. The synchronized DG sweep operation with biasing of VTG and VBG (=10 VTG) increased the carrier mobility by a factor of 4.85 compared with the independent DG sweep. Direct-current analysis and low-frequency noise modeling indicate that the device performance improves under equivalent gate voltages from both sides, because the device operates in a low vertical electric field and the interfacial carrier fluctuation effect is significantly reduced.

A method for representation and analysis of conformal cooling channels in molds made of functionally graded tool steel/Cu materials

Advances in additive manufacturing technology (AMT) enable the direct fabrication of thermally conductive molds with heat sinks or conformal cooling channels. Although tool steels (e.g., P21, H13, SUS420J2) are popularly used as die materials because of high dimensional stability, tool steels are inefficient for cooling mold dies due to low thermal conductivity. Hence, the adoption of functionally graded tool steel/Cu materials (FGMs) has good potentials for thermally conductive molds to avoid thermal stress concentration while improving thermal conductivity. In this sense, this paper presents a new method for the representation and analysis of conformal cooling channels in molds (injection or blowing) made of functionally graded tool steel/Cu materials. A heterogeneous sweep operation combined with 2D material blending was proposed to construct heterogeneous solid models for conformal cooling channels. In addition, one-dimensional P21/Cu FGMs were fabricated using DMT (laser-aided direct metal tooling). Material properties (such as density, specific heat, thermal conductivity, coefficient of thermal expansion, and hardness) were evaluated to obtain more accurate analysis results and to verify the feasibility of such a multi-functional mold. An example is shown to illustrate the entire representation and analysis procedure.

Decoding the metallic bridging dynamics in nanogap atomic switches.

Atomic switches are promising candidates as the basic building blocks for large-scale neuromorphic networks due to their tunable switching behaviors. Several neuromorphic components based on atomic switches have been demonstrated, including artificial synapses, artificial neurons and short-term to long-term memory, making it possible to construct neuromorphic systems using a unified device. Although the mechanism of atomic switches has been actively studied, most of the discussions in previous studies are qualitative and failed to provide a comprehensive view of the dynamics that can precisely describe the metallic bridging under an electric field. In this paper, we designed a gap-type atomic switch and realized various switching behaviors, including both volatile and non-volatile resistive switching. Employing advanced microanalysis technology, we experimentally studied the switching mechanism and captured the nanoscale metallic filament in gap-type atomic switches. Furthermore, based on the experimental findings as well as on the electrochemistry fundamental and electron tunneling effect, we proposed a physical model that precisely reproduced the sophisticated switching behaviors. Our model mathematically described the growth/shrinkage dynamics of nanoscale metallic filaments, providing a direction for studying the switching behaviors from a quantitative view. The simulation results are in good agreement with the experimental findings in both DC sweep and pulse operation modes. In addition, we have demonstrated neuronal tonic spiking and short-term to long-term memory in experiment and simulation, indicating that our model can be applied to the circuit level simulation of large-scale atomic switch arrays for neuromorphic applications.

Characterization of Environmental Pollutants in Sediment Collected during Street Sweeping Operations to Evaluate its Potential for Reuse

AbstractStreet sweeping is a routine roadway maintenance activity that functions as a nonstructural stormwater best management practice. Further, the road-deposited sediment collected during sweepi...

Effect of Soil Management Practices on the Sweeping Operation during Coffee Harvest

Core Ideas The harvest performance can be affected by plant phenological behavior, non‐uniform fruit ripening, late harvest, pests and diseases, rods vibration intensity, displacement velocity and, finally, slope. After harvesting, the approximately 10–20% of coffee cherries that fall on the ground are known as the sweeping coffee and require a gathering operation. The mechanical sweeping and gathering allow higher operational capacity (working greater areas in shorter times), thus increasing profitability and reducing operational costs, however, these machines are sensitive to oscillation and/or soil topography. In addition to this limiting factor, one of the main obstacles to mechanical picking of sweeping coffee is the subsoiling operation that consists of unpacking the soil by moving the soil surface of the coffee interlines, where the coffee berries are to be harvested later . In this context, assuming that the subsoiling operation could affect the losses during the mechanical picking of sweeping coffee, this study aimed at using the SPC tools to monitor the ability of management processes to reduce losses in the sweeping and mechanical picking of fallen coffee for four soil managements. The mechanical sweeping and picking of coffee berries are necessary to recover berries that naturally fall on the soil during the mechanical harvesting process. The soil characteristics and the materials that are collected affect these two operations; in addition, there are reports that suggest that mechanical sweeping and picking are hampered by subsoiling. In this regard, the current study evaluated losses during the mechanical sweeping and picking of coffee cultivated under four soil management treatments in Presidente Olegário, MG, Brazil. The four treatments consisted of the following soil management practices: subsoiling and crushing; subsoiling and harrowing; subsoiling followed by harrowing and crushing; and the control, with no soil management. The soil was prepared in 2014, while the coffee sweeping and picking occurred in 2015 and 2016. The experimental design followed the assumptions of statistical process control, and fifteen points were evaluated per treatment in accordance with the statistical process control guidelines. The lowest loss rates were obtained for the subsoiling and crushing soil management treatment, whereas harrowing after subsoiling led to the highest losses and the lowest process quality.

Modelling approach for soil displacement in tillage using discrete element method

The majority of studies dedicated to the dynamic behaviour of agricultural soils are basically focused on prediction of physical conditions within the soil-tool interface whereas the dynamic soil response, such as soil displacement, has not attracted sufficient attention. Considering its importance for engineering applications, the objective of the presented study was to develop a modelling approach to study the soil displacement due to soil interaction with operating tool during sweep cultivation. The developed approach employs the similarity criteria to account for the effect of scaling-up soil particle sizes on model quality and combines (i) an empirical study of soil displacement during a sweep operation and (ii) related numerical simulations using a discrete element model. Soil displacement for three different soil types in soil bins was measured using a tracer methodology. The discrete element model was formulated for cohesive soils with parallel bond contacts between aggregates. The model allows simulation of mechanical tests (used for calibration purposes) and simulation of soil interaction with operating tool during sweep cultivation. This work shows that due to the necessary change in particle sizes of model soil, the conditions of physical equivalence between the model and natural soil can be difficult to satisfy. Such condition can cause significant dissimilarity between measured and simulated soil displacement. However, this can be overcome if the model scaling does not exceed a certain limit which is determined by soil structure and the potential contact density on a tool’s contact surface during the soil-tool interaction. By using these findings, our simulations demonstrate that prediction of soil displacement is possible within the suggested approach with sufficient accuracy.

Risk evaluation and games in mine warfare considering shipcounter effects

Mines are believed to have suitable cost performance because cheap weapons prevent opponents from freely engaging in activity in mined areas for a comparatively long time. Mine warfare (MW) can be regarded as combat between a minefield planner and mine countermeasure (MCM) forces. The minefield planner equips influence mines with mine counter-countermeasures (MCCMs), which increase the difficulty of their removal. One of the MCCMs is a mine shipcounter, which provides a mine detonation fuse that triggers with some delay after the mine sensor detects vessels. In this paper, we develop a mathematical model of the MCM operation against scattered naval mines with shipcounters and analyze MW as a two-sided warfare game between the minefield planner and the MCM forces. The MCM forces must make a clever choice between mine-hunting or sweeping operations because, depending on the MCM operations, the shipcount has different effects on the removal of mines or on the damage risk to civilian ships transiting in a channel. First, we evaluate the performances of hunting and sweeping considering the mine shipcount; second, we consider a simple game with the minefield planner and the MCM forces as players and analyze rational strategies for these decision makers in MW.

From the Editor's Gable

From the Editor's Gable