Wide Input Range Research Articles

A 16‐bit, ±10‐V Input Range SAR ADC with a 5‐V Supply Voltage and Mixed‐Signal Nonlinearity Calibration

This paper presents a high-precision, successive approximation register (SAR) analog-to-digital converter (ADC) with resistive analog front-end for low-voltage and wide input range applications. To suppress the serious nonlinearity brought by the voltage coefficients of analog front-end without deteriorating differential nonlinearity performance, a mixed-signal calibration scheme based on piecewise-linear method with calibration digital-to-analog converter is proposed. A compensation current is designed to sink or source from the reference to keep it independent of input signal, which greatly improves the linearity performance. Fabricated in a 0.5-μm CMOS process, the proposed ADC achieves 88-dB signal-to-noise-and-distortion ratio and 103-dB spurious free dynamic range with 5-V supply voltage and 2.5-V reference voltage, and the total power consumption is 37.5 mW.

Engaging at the science-policy interface as an early-career researcher: experiences and perceptions in biodiversity and ecosystem services research

ABSTRACT Effective knowledge exchange at science-policy interfaces (SPIs) can foster evidence-informed policy-making through the integration of a wide range of knowledge inputs. This is especially crucial for conservation and sustainable use of biodiversity and ecosystem services (ES), human well-being and sustainable development. Early-career researchers (ECRs) can contribute significantly to knowledge exchange at SPIs. Recognizing that, several capacity building programs focused on sustainability have been introduced recently. However, little is known about the experiences and perceptions of ECRs in relation to SPIs. Our study focused on SPI engagement of ECRs who conduct research on biodiversity and ES, as perceived and experienced. Specifically, we addressed ‘motivations’, ‘barriers’ and ‘opportunities and ‘benefits’. A total of 145 ECRs have completed the survey. Our results showed that ECRs were generally interested to engage in SPIs and believed it to be beneficial in terms of contributing to societal change, understanding policy processes and career development. Respondents perceived lack of understanding about involvement channels, engagement opportunities, funding, training, perceived credibility of ECRs by other actors and encouragement of senior colleagues as barriers to engaging in SPIs. Those who have already participated in SPIs generally saw fewer barriers and more opportunities. A key reason for dissatisfaction with experience in SPIs was a lack of impact and uptake of science-policy outputs by policymakers – an issue that likely extends beyond ECRs and implies the need for transformations in knowledge exchange within SPIs. In conclusion, based on insights from our survey, we outline several opportunities for increased and better facilitation of ECR engagement in SPIs.

Robust Adaptive Beamforming Based on Subspace Decomposition, Steering Vector Estimation and Correction

Considering that the performance of adaptive arrays is sensitive to any type of mismatches, an innovative robust adaptive beamforming method based on covariance matrix reconstruction, subspace decomposition, steering vector estimation and correction is proposed. Based on Capon spatial spectrum, a group of angle sets containing all interfering signals are determined, and the interference covariance matrix can be reconstructed with a smaller integration interval. On the other hand, the sample covariance matrix can be decomposed into signal subspace and interference-plus-noise by using the principle of maximum correlation. Based on the interference-plus-noise subspace and the reconstructed signal-plus-noise covariance matrix, a new convex optimization model is built to estimate the steering vector of the desired signal. Then, an improved projection approach based on signal subspace is designed for correction to improve the robustness against the nominal direction vector mismatches. Simulation results demonstrate that the proposed method achieves better overall performance under multiple mismatches over a wide range of input signal-to-noise ratios.

Automatic Rate and Rate-Integrating Mode-Switchable Axisymmetric Gyroscope.

This paper describes a novel rate and rate-integrating mode-switchable axisymmetric gyroscope. A precession angle tracking algorithm is developed to enable the gyro to switch automatically between rate and rate-integrating modes at preset rate points through a digital control system within the gyro. We also propose a vibrating amplitude control method for the rate-integrating mode that directly extracts the angular rate output to ensure switching stability. In rate mode, the bias instability and angle random walk of the gyro reach 0.106°/h and 0.011°/√h, respectively. Additionally, an input range of over ±5000°/s is measured in rate-integrating mode. The scale factor nonlinearity reaches approximately 116 ppm over the full-scale range. The control system implements effective steering control of the gyroscope, with a switching delay of 10 ms from rate mode to rate-integrating mode and 100 ms from rate-integrating to rate mode. The proposed system actualizes a new type of gyroscope with high accuracy and a wide input range, which combines the benefits of rate and rate-integrating modes.

Assessing the Health and Economic Outcomes of a 9-Valent HPV Vaccination Program in the United Kingdom.

Background: The United Kingdom (UK) switched from using the 4-valent human papillomavirus (HPV) vaccine (Gardasil®) to the 9-valent vaccine (Gardasil 9®) in 2021.Objective: To estimate and compare the health and economic outcomes of 2 HPV vaccination programs in the UK targeting girls and boys aged 12-13 years from the perspective of the UK National Health Service. The 2 vaccination strategies were (1) universal vaccination 4-valent (UV4V), using the 4-valent HPV vaccine (4vHPV), and (2) universal vaccination 9-valent (UV9V), using the 9-valent HPV vaccine (9vHPV).Methods: A deterministic heterosexual compartmental disease transmission model was used to track health and economic outcomes over a 100-year time horizon. Outcomes were discounted at an annual rate of 3.5% and 1.5%. All costs were adjusted to 2020 British pounds (£). Health outcomes were measured in quality-adjusted life-years (QALYs), and the summary results were presented as incremental cost-effectiveness ratios (£/QALY gained) when comparing UV4V with UV9V.Results: Using the same vaccine coverage for both programs, the total cumulative cases of HPV-related health outcomes tracked over the 100-year horizon indicated that the relative number of cases averted (UV9V vs UV4V) ranged from 4% (anal male cancers and deaths) to 56% (cervical intraepithelial neoplasia [CIN1]). Assuming that 9vHPV cost £15.18 more than 4vHPV (a cost differential based on discounted list prices), the estimated incremental cost-effectiveness ratio was £8600/QALY gained when discounted at 3.5%, and £3300/QALY gained when discounted at 1.5%. The estimated incremental cost-effectiveness ratios from the sensitivity analyses remained <£28000/QALY over a wide range of parameter inputs and demonstrated that disease utilities, discount rate, and vaccine efficacy were the 3 most influential parameters.Discussion: Consistent with other published studies, the results from this study found that the 9vHPV vaccine prevented a substantial number of cases when compared with the 4vHPV vaccine and was highly cost-effective.Conclusions: These results demonstrate that replacing universal 4vHPV with 9vHPV can prevent a substantial additional number of HPV-related cases/deaths (in both women and men) and remain cost-effective over a range of 9vHPV price premiums.

Assessing the Health and Economic Outcomes of a 9-Valent HPV Vaccination Program in the United Kingdom

Background: The United Kingdom (UK) switched from using the 4-valent human papillomavirus (HPV) vaccine (Gardasil®) to the 9-valent vaccine (Gardasil 9®) in 2021. Objective: To estimate and compare the health and economic outcomes of 2 HPV vaccination programs in the UK targeting girls and boys aged 12-13 years from the perspective of the UK National Health Service. The 2 vaccination strategies were (1) universal vaccination 4-valent (UV4V), using the 4-valent HPV vaccine (4vHPV), and (2) universal vaccination 9-valent (UV9V), using the 9-valent HPV vaccine (9vHPV). Methods: A deterministic heterosexual compartmental disease transmission model was used to track health and economic outcomes over a 100-year time horizon. Outcomes were discounted at an annual rate of 3.5% and 1.5%. All costs were adjusted to 2020 British pounds (£). Health outcomes were measured in quality-adjusted life-years (QALYs), and the summary results were presented as incremental cost-effectiveness ratios (£/QALY gained) when comparing UV4V with UV9V. Results: Using the same vaccine coverage for both programs, the total cumulative cases of HPV-related health outcomes tracked over the 100-year horizon indicated that the relative number of cases averted (UV9V vs UV4V) ranged from 4% (anal male cancers and deaths) to 56% (cervical intraepithelial neoplasia [CIN1]). Assuming that 9vHPV cost £15.18 more than 4vHPV (a cost differential based on discounted list prices), the estimated incremental cost-effectiveness ratio was £8600/QALY gained when discounted at 3.5%, and £3300/QALY gained when discounted at 1.5%. The estimated incremental cost-effectiveness ratios from the sensitivity analyses remained &lt;£28000/QALY over a wide range of parameter inputs and demonstrated that disease utilities, discount rate, and vaccine efficacy were the 3 most influential parameters. Discussion: Consistent with other published studies, the results from this study found that the 9vHPV vaccine prevented a substantial number of cases when compared with the 4vHPV vaccine and was highly cost-effective. Conclusions: These results demonstrate that replacing universal 4vHPV with 9vHPV can prevent a substantial additional number of HPV-related cases/deaths (in both women and men) and remain cost-effective over a range of 9vHPV price premiums.

Output Regulation With Integrated SR Switch Duty Cycle Control for Wireless Power Transfer Systems

Due to the physical separation between primary and secondary sides, achieving a good output regulation in a wireless power transfer (WPT) system is nontrivial. Typically, an additional dc–dc converter stage at the secondary side or a radio frequency (RF) communication link between the primary and secondary sides is used to regulate the output. However, these approaches are not always practical in many industrial applications where there is a size constraint, or the noise interference that tends to interrupts the RF link. In this article, an integrated secondary-side regulation scheme without extra devices or communication requirement is proposed. The duty cycle of the secondary-side synchronous rectification (SR) device is controlled to regulate the output independently of the primary. The SR duty modulation allows voltage regulation over a wide load range or current regulation over a wide input range while avoiding the additional dc–dc converter stage. Thus, the primary-side control can operate under the fixed-duty condition while maintaining zero-voltage switching (ZVS) for all switches in the entire power range. A 48-V/190-W GaN high-electron-mobility transistor (HEMT)-based prototype has been built and tested to verify the feasibility of the proposed control scheme.

A 1.8-2.7 GHz Triple-Band Low Noise Amplifier with 31.5 dB Dynamic Range of Power Gain and Adaptive Power Consumption for LTE Application.

This paper presents a multi-gain radio frequency (RF) front-end low noise amplifier (LNA) utilizing a multi-core based on the source degeneration topology. The LNA can cover a wide range of input and output frequency matching by using a receiver (RX) switch at the input and a capacitor bank at the output of the LNA. In the proposed architecture here, to avoid the saturation of RX chain, 12 gain steps including positive, 0 dB, and negative power gains are controlled by a mobile industry processor interface (MIPI). The multi-core architecture offers the ability to control the power consumption over different gain steps. In order to avoid the phase discontinuity, the negative gain steps are provided using an active amplification and T-type attenuation path that keeps the phase discontinuity below ±5 degrees between two adjacent power gain steps. Using the multi-core structure, the power consumption is optimized in different power gains. The structure is enhanced with the adaptive variable cores and reactance parameters to maintain different power consumption for different gain steps and remain the output matching in an acceptable operating range. Furthermore, auxiliary linearization circuitries are added to improve the input third intercept point (IIP3) performance of the LNA. The chip is fabricated in 65 nm complementary metal-oxide semiconductor (CMOS) silicon on insulator (SOI) process and the die area is 0.308 mm2. The proposed architecture achieves the IIP3 performance of −10.2 dBm and 8.6 dBm in the highest and lowest power gains, which are 20.5 dB and −11 dB, respectively. It offers the noise figure (NF) performance of 1.15 dB in the highest power gain while it reaches 14 dB when the power gain is −11 dB. The LNA consumes 16.8 mA and 1.33 mA current from a 1 V power supply that is provided by an on-chip low-dropout (LDO) when it operates at the highest and lowest gains, respectively.

Effect of Melt and Mold Temperature on Fiber Orientation during Flow in Injection Molding of Reinforced Plastics

Abstract Injection molding, a highly productive manufacturing process, is one of the most versatile production methods in plastic manufacturing industry. It is capable of producing intricate net shapes without requiring finishing treatment and with good dimensional accuracy. In injection molding of reinforced thermoplastics the properties of the final product highly depend on the state of fiber orientation. Tailoring the fiber orientation in the final product, in order to control the properties, is the basic motivation of this study. Among different parameters, which could affect the orientation patterns, this study is concerned on analyzing the effects of mold and melt temperature on the state of fiber orientation during flow. In contrast to the melt temperature, which has a limited range for variation, mold temperature provides wide range of possible input at different locations such that by revealing its effect it could become one of the most attractive parameters in controlling the properties of injection molded fiber reinforced thermoplastic products.

Control Optimization of Modular Multilevel Resonant DC Converters for Wide-Input-Range MVdc to LVdc Applications

In this article, the output voltage control strategy of modular multilevel resonant dc converters (MMRDC) for medium-voltage wide-input-range applications is studied. First, the feasibility and influence of the switching frequency regulation and modulation index regulation are investigated in detail. It is found that the switching frequency choice has a significant effect on the voltage stress of arm inductors and the transformer. Then, based on these considerations, the modulation index regulation plus switching frequency regulation based design and control optimization is proposed. With the proposed design and control method, the switching frequency range for adapting to a wide input range is further reduced, especially under light load operating conditions. Besides, the high voltage stress on arm inductors is avoided and the high voltage <i>dv</i>&#x002F;<i>dt</i> on the transformer is also eliminated. Finally, a laboratory prototype with 8&#x2013;16 kV input and 375 V&#x002F;60 kW output has been built and the experimental validation under a wide input range has been done. The efficiency over 96.4&#x0025; under the wide input range proved the effectiveness of the optimized control methods.

Dry reforming of methane in a nanosecond repetitively pulsed discharge: chemical kinetics modeling

Nanosecond pulsed discharge plasma shows a high degree of non-equilibrium, and exhibits relatively high conversions in the dry reforming of methane. To further improve the application, a good insight of the underlying mechanisms is desired. We developed a chemical kinetics model to explore the underlying plasma chemistry in nanosecond pulsed discharge. We compared the calculated conversions and product selectivities with experimental results, and found reasonable agreement in a wide range of specific energy input. Hence, the chemical kinetics model is able to provide insight in the underlying plasma chemistry. The modeling results predict that the most important dissociation reaction of CO2 and CH4 is electron impact dissociation. C2H2 is the most abundant hydrocarbon product, and it is mainly formed upon reaction of two CH2 radicals. Furthermore, the vibrational excitation levels of CO2 contribute for 85% to the total dissociation of CO2.

Robust adaptive beamforming based on covariance matrix reconstruction with RCB principle

In this paper, a novel robust adaptive beamforming (RAB) technique based on the covariance matrix reconstruction is proposed to solve the array model mismatch. The proposed technique provides an alternative method to reconstruct the interference-plus-noise covariance matrix (IPNCM) and estimate the steering vector (SV) of the desired signal. In particular, an unknown error exists in the SV of the considered array. The proposed RAB algorithm adopts the robust Capon beamformer (RCB) principle to roughly estimate the SVs of the desired and interference signals. Based on those preliminary estimated SVs, an improved Capon power spectrum is constructed. Then the interference covariance matrix is reconstructed by utilizing the modified Capon power spectrum integrated over the union of several disjoint angular sectors. Then, the reconstructed covariance matrix is further refined by exploring the low rank property. Meanwhile, the SV of the desired signal is estimated by solving a modified quadratically constrained quadratic programming (QCQP) problem. The simulation results show that the RCB principle provides an accurate IPNCM reconstruction, and the proposed RAB algorithm outperforms the existing RAB techniques over a wide range of input signal-to-noise ratio (SNR) region under various mismatch conditions.

ALTERNATIVE APPROACH TO SMALL SCALE PHOTOVOLTAIC SOLAR POWER AND ENERGY STORAGE

Photovoltaic solar panels remain one of the most commonly available avenues for acquiring renewable energy for small-scale end users but despite their promising potential their implementation continues to remain outside the realm of possibility for most. The combination of high upfront costs, long payback periods, and complex installation requirements results in a disincentive to purchase the technology and relies on significant appeals to morality as a driving force as opposed to purely economic incentives. An alternative implementation of photovoltaic arrays for small scale use combined with grid power supplement is herein proposed that better matches energy consumption profiles in the household and seeks to reduce cost and complexity. The system comprises a hydronic thermal storage system acting as hot water supply, furnace, and air conditioning for power regulation and distribution in combination with electrical distribution to home appliances using minor modification to the power supply. Currently used batteries, charge controllers, and inverters are eliminated and replaced with a single specialized outdoor central air-conditioning condenser unit that distributes electrical and thermal energy but would not supply electricity onto the grid. Examination of minor electronic modifications on common switched mode power supply topologies has found that regulation of a wide range of variable voltage solar electricity input is currently possible and does not cause overheat or other harm to the power supply. The proposal provides a workable solution to alleviate financial and technical burden on the individual and promotes the vision of a 100% renewable energy society while working within economic constraints.

Exploring Potential of a Tribal Region: The Case of the Dang District, Gujarat, India

In the 21st century, tourism is becoming one of the fastest-growing economic sectors. Tourism is a “large and complex human activity that requires a wide range of services, infrastructure and inputs”. Over the past half- century, tourism has opened up many opportunities around the world. Tourism is an economic engine that brings many sources of income to the country, but it also has many potential challenges, complications and potential negative impacts on the environment, culture and community. Key Words: Eco-Tourism, NTFP, Tribes, Craft, Rural-Tourism

Simulation-based assessment of safe operating windows and optimization in full-scale seawater reverse osmosis systems

Reverse osmosis (RO) is the most widely used desalination technology for both seawater and brackish water. Unfortunately, RO remains an energy intensive technology despite the efforts being made to overcome this drawback. One of the factors that could help to minimize this issue is the optimal design and operation of RO systems. Membrane manufacturers are continuously improving and releasing new spiral wound membrane modules (SWMMs) that nonetheless need to be studied in order to determine how to achieve the best highest possible performance from them. The aim of this study was to evaluate the safe operating windows (SOWs) of 9 commercial SWMMs in pressure vessels (PVs) with 7 of these elements in a single stage seawater reverse osmosis (SWRO) system. The permeability coefficients of the SWMMs were taken from a novel membrane open database. These coefficients and the characteristics of the SWMMs were introduced in a simulation algorithm to estimate the behavior of the SWRO system. SOWs were determined without considering any energy recovery device, although these were considered for the calculation of the minimum energy consumption. The SWMMs were compared and the optimal operating points were identified for each one. The results showed the highest difference was around 0.2 kWhm−3 between SWMMs in their optimal operating point with respect to the minimum specific energy consumption. It was also found that this difference increases slightly with rises in feedwater concentration. For a wide range of PV power inputs, the SWMMs were able to reach quite similar maximum flux recovery rates. Experimental work is needed to obtain more reliable predictions of SWRO systems working in wide operating ranges.

Increasing EMI Immunity and Linearity of a CMOS 180 nm Voltage-to-Delay Converter

This paper presents a voltage-controlled delay unit (VCDU) with a novel architecture allowing for a wide input range of linearity and an improved immunity to electromagnetic interferences. The circuit is based on a current-starved inverter with a biasing technique to extend the input voltage range of linearity near to the rail-to-rail linearity range. The proposed scheme was designed by UMC 180 nm standard CMOS process and works without power-hungry amplifiers or comparators. It has a voltage supply of 1.8 V and exhibits a rail-to-rail linearity range (0–1.8 V) with an average EMI-induced jitter of only 1% of the nominal delay.

Ten years of image analysis and machine learning competitions in dementia

Machine learning methods exploiting multi-parametric biomarkers, especially based on neuroimaging, have huge potential to improve early diagnosis of dementia and to predict which individuals are at-risk of developing dementia. To benchmark algorithms in the field of machine learning and neuroimaging in dementia and assess their potential for use in clinical practice and clinical trials, seven grand challenges have been organized in the last decade: MIRIAD (2012), Alzheimer’s Disease Big Data DREAM (2014), CADDementia (2014), Machine Learning Challenge (2014), MCI Neuroimaging (2017), TADPOLE (2017), and the Predictive Analytics Competition (2019). Based on two challenge evaluation frameworks, we analyzed how these grand challenges are complementing each other regarding research questions, datasets, validation approaches, results and impact.The seven grand challenges addressed questions related to screening, clinical status estimation, prediction and monitoring in (pre-clinical) dementia. There was little overlap in clinical questions, tasks and performance metrics. Whereas this aids providing insight on a broad range of questions, it also limits the validation of results across challenges. The validation process itself was mostly comparable between challenges, using similar methods for ensuring objective comparison, uncertainty estimation and statistical testing. In general, winning algorithms performed rigorous data pre-processing and combined a wide range of input features.Despite high state-of-the-art performances, most of the methods evaluated by the challenges are not clinically used. To increase impact, future challenges could pay more attention to statistical analysis of which factors (i.e., features, models) relate to higher performance, to clinical questions beyond Alzheimer’s disease, and to using testing data beyond the Alzheimer’s Disease Neuroimaging Initiative. Grand challenges would be an ideal venue for assessing the generalizability of algorithm performance to unseen data of other cohorts. Key for increasing impact in this way are larger testing data sizes, which could be reached by sharing algorithms rather than data to exploit data that cannot be shared. Given the potential and lessons learned in the past ten years, we are excited by the prospects of grand challenges in machine learning and neuroimaging for the next ten years and beyond.

High efficiency step‐up DC–DC converter for grid‐connected photovoltaic microinverter applications

This paper presents a resonant step-up DC–DC converter for the photovoltaic micro-inverter system and describes the converter's operation principle in detail. In the proposed converter, the active-clamp technique is used to reduce the high voltage spike of the main power switch during its turns-off. Meanwhile, the output rectifier diodes can operate in the zero-current-switching (ZCS) operation and the clamping power switch can operate in zero-voltage-switching (ZVS) condition with the series LC resonant circuit. Then, the design procedure for the key components of the proposed DC–DC converter is derived. Finally, experimental prototype with 300 W is established to verify the validity of the proposed topology, and the experimental results shows that the proposed topology processes the merits of few components, simple control, galvanic isolation and high conversion efficiency in a wide photovoltaic voltage input and power range.

Invited Session II: Retinal mechanisms mediating vision: Light adaptation in primate fovea

Our visual performance varies remarkably across space. For instance, our central vision exhibits the highest spatial and chromatic sensitivity, whereas temporal sensitivity is higher for our peripheral than central vision. Our high-acuity central vision is initiated in the cone photoreceptors which are packed in a dense array in the fovea. The density and morphology of cones differ remarkably between foveal and peripheral primate retina, but our knowledge about their functional differences remain quite poor. In the past we have shown that cone signals in the fovea are two-fold slower than in the peripheral retina consistent with the difference in the temporal sensitivity of cone-mediated vision to high-frequency flicker. But we are far from understanding the full breadth of these topographic differences in cone signaling across primate retina over a wide range of light inputs. I will present recent results of a detailed comparison of functional properties - such as kinetics, gain and cellular noise - of cones in the fovea with that in rest of the primate retina. I will show how foveal cones adapt across a wide range of lumice and if they exhibit differences in the amplitude, kinetics or timescales of adaptation when compared to cones in the peripheral primate retina. Lastly, I will share our findings on the relative contribution of cone vs circuit mechanisms towards lumice adaptation in the domit neural circuit in the fovea - the midget ganglion cell pathway.

Membrane phospholipids control activity of the mechanosensitive K2P channel TREK1

Tandem pore (K2P) potassium ion channels play vital roles in human physiology, chiefly responsible for maintaining cellular resting membrane potential. Modulation of K2P channel activity controls cellular excitability, altering the degree of input signal required to reach action potential thresholds. For the mechanosensitive subfamily of K2Ps, including the TREK1, TREK2, and TRAAK channels, a wide range of diverse and dissimilar inputs alter channel activity, including pH, heat, mechanical stretch, lipids, post-translational modification, and an array of pharmacologically active agents including volatile anesthetics, antidepressants, and neuroprotective agents.