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A new compact model for HfO 2 -based ferroelectric tunnel junction (FTJ) memristors is constructed based on detailed physical modeling using calibrated TCAD simulations. A multi-domain configuration of the ferroelectric material is demonstrated to produce quasi-continuous conductance of the FTJ. This behavior is demonstrated to enable a robust spike-timing-dependent plasticity-type learning capability, making FTJs suitable for use as synaptic memristors in a spiking neural network. Using both TCAD–SPICE mixed-mode and pure SPICE compact model approaches, we apply the newly developed model to a crossbar array configuration in a handwritten digit recognition neuromorphic system and demonstrate an 80% successful recognition rate. The applied methodology demonstrates the use of TCAD to help develop and calibrate SPICE models in the study of neuromorphic systems.

The aim of this work is to create an artificial environment LED based for plants where the goal is to control LED lighting and monitor plant growth. This will contribute on issue like food production. This work involves the use of a web development microcontroller kit, which will help to make online or IoT (Internet of Things) project and design easy. The microcontroller will come with an integrated Wi-Fi to collect and control variable parameter and also programming language to develop graphical user interface (GUI). It is expected that the plant growth environment can be monitored and controlled or set through cloud via Wi-Fi on the board. Multicolour light emitting diode (LED) lamps are used. This system will improve the performance of available plant growth area where it will become more flexible in term of providing artificial environment with a better supervision.

In recent years, multi-axis robots are indispensable in automated factories due to the rapid development of Industry 4.0. Many related processes were required to have the increasing demand for accuracy, reproducibility, and abnormal detection. The monitoring function and immediate feedback for correction is more and more important. This present study integrated a highly sensitive lithium niobate (LiNbO3) vibration sensor as a sensor node (SN) and architecture of wireless mesh network (WMN) to develop a monitoring system (MS) for the robotic arm. The advantages of the thin-film LiNbO3 piezoelectric sensor were low-cost, high-sensitivity and good electrical compatibility. The experimental results obtained from the vibration platform show that the sensitivity achieved 50 mV/g and the reaction time within 1 ms. The results of on-site testing indicated that the SN could be configured on the relevant equipment quickly and detect the abnormal vibration in specific equipment effectively. Each SN could be used more than 10 h at the 80 Hz transmission rate under WMN architecture and the loss rate of transmission was less than 0.01% within 20 m.

A lattice temperature model is derived for oxide-confined vertical cavity surface emitting lasers (VCSELs) based on carrier transport and the conservation of energy. Peltier heat is caused by the bandedge and quasi-Fermi level discontinuities at a heterojunction. However, considering the device size, Peltier heat needs to be distributed and is not just generated at the interface, otherwise, an anomolous spike in temperature will occur. We have developed a novel treatment to model the Peltier heat at a heterojunction by use of a Monte Carlo simulation. Peltier heat is found to be a major heat contributor, and it results in a rapid and high temperature rise in the separate confinement heterostructure (SCH) region of the laser diode. We have also shown that the carrier thermal conductivities for materials with high mobilities must be included at high carrier densities because they contribute to additional spreading of the thermal energy. Subsequently, this lattice temperature model is coupled self-consistently to electronic and optical solvers to form a complete simulator for VCSELs. Self-heating causes a fast temperature rise when the VCSEL is operated under continuous wave conditions, causing resonant wavelength changes and an eventual thermal rollover. The resonant wavelength shift has been shown to be caused mainly by the heating of the distributed Bragg reflectors even though the peak temperature occurs within the SCH region. Possible physical factors causing the thermal rollover have also been examined with our complete simulator. The Auger recombination process is found to be one of the main factors causing the thermal rollover in 980 nm oxide-confined VCSELs while the photon lifetime is a factor in determining the position of the thermal rollover. We have also achieved a very good match between our simulated results and experimental data.

Our numerical simulations of vertical cavity surface emitting lasers with Minilase demonstrate that a diffusion capacitance is induced by the minority carriers accumulated in the separate confinement regions. This diffusion capacitance is shown to be responsible for the over-damping of the modulation response and the reduction of the modulation bandwidth. It is also demonstrated that this diffusion capacitance is significantly suppressed by grading the separate confinement hetero-junctions (SCHs) or reducing the thickness of the SCHs.

We have developed a fully self-consistent and coupled electronic-thermal-optical simulator for vertical cavity surface emitting lasers (VCSELs). The lattice temperature model is derived based on carrier transport and the conservation of energy. A novel treatment is applied to model distributed Peltier heat at a heterojunction by use of a Monte Carlo simulation. Peltier heat is found to be a major heat contributor, and it results in a rapid and high temperature rise in the separate confinement heterostructure (SCH) region of the laser diode. Carrier thermal conductivities for materials with high mobilities at high carrier densities must be included to account for additional spreading of the thermal energy. Both scalar and vector optical mode solvers for VCSELs have been developed. The scalar self-consistent effective index method (S-EIM) has been shown to compute accurate resonant wavelength, mode profile, and threshold loss as compared to the vector Green's function method and experimental results. The vector model is based on rigorous mode matching and has been formulated to be efficient both in computation volume and speed. The S-EIM method is subsequently used to show that grading the SCH region differently in oxide-confined VCSELs results in wavelength shifts. These shifts can be attributed to two effects: the inward shift of an effective index step that redefines the λ cavity confinement boundary, and the reduction of the effective index step leading to relaxed confinement abilities of the λ cavity. The revised understanding of the physics of resonance in a VCSEL hence allows us to compensate the wavelength shifts appropriately. We have investigated the important self-heating effects of thermal lensing and output light power saturation of oxide-confined VCSELs with our complete simulator. The resonant wavelength shift in thermal lensing has been shown to be caused mainly by the heating of the distributed Bragg reflectors. Possible physical factors causing the thermal rollover have been examined. The Auger recombination process is found to be a main contributor to the thermal rollover in 980 nm oxide-confined VCSELs. We have also achieved a very good match between our simulated results and experimental data.

Living in an urban environment may increase the risk of developing inflammatory bowel disease (IBD). It is unclear if this observation is seen globally. We conducted a population-based study to assess the relationship between urbanization and incidence of IBD in the Asia-Pacific region. Newly diagnosed IBD cases between 2011 and 2013 from 13 countries or regions in Asia-Pacific were included. Incidence was calculated with 95% confidence interval (CI) and pooled using random-effects model. Meta-regression analysis was used to assess incidence rates and their association with population density, latitude, and longitude. We identified 1175 ulcerative colitis (UC), 656 Crohn's disease (CD), and 37 IBD undetermined (IBD-U). Mean annual IBD incidence per 100 000 was 1.50 (95% CI: 1.43-1.57). India (9.31; 95% CI: 8.38-10.31) and China (3.64; 95% CI, 2.97-4.42) had the highest IBD incidence in Asia. Incidence of overall IBD (incidence rate ratio [IRR]: 2.19; 95% CI: 1.01-4.76]) and CD (IRR: 3.28; 95% CI: 1.83-9.12) was higher across 19 areas of Asia with a higher population density. In China, incidence of IBD (IRR: 2.37; 95% CI: 1.10-5.16) and UC (IRR: 2.63; 95% CI: 1.2-5.8) was positively associated with gross domestic product. A south-to-north disease gradient (IRR: 0.94; 95% CI: 0.91-0.98) was observed for IBD incidence and a west-to-east gradient (IRR: 1.14; 95% CI: 1.05-1.24) was observed for CD incidence in China. This study received IRB approval. Regions in Asia with a high population density had a higher CD and UC incidence. Coastal areas within China had higher IBD incidence. With increasing urbanization and a shift from rural areas to cities, disease incidence may continue to climb in Asia.

To understand racial bias in clinical settings from the perspectives of minority patients and healthcare providers to inspire changes in the way healthcare providers interact with their patients. Articles on racial bias were searched on Medline, CINAHL, PsycINFO, Web of Science. Full text review and quality appraisal was conducted, before data was synthesized and analytically themed using the Thomas and Harden methodology. 23 articles were included, involving 1,006 participants. From minority patients' perspectives, two themes were generated: 1) alienation of minorities due to racial supremacism and lack of empathy, resulting in inadequate medical treatment; 2) labelling of minority patients who were stereotyped as belonging to a lower socio-economic class and having negative behaviors. From providers' perspectives, one theme recurred: the perpetuation of racial fault lines by providers. However, some patients and providers denied racism in the healthcare setting. Implicit racial bias is pervasive and manifests in patient-provider interactions, exacerbating health disparities in minorities. Beyond targeted anti-racism measures in healthcare settings, wider national measures to reduce housing, education and income inequality may mitigate racism in healthcare and improve minority patient care.

Telehealth interventions are effective in hypertension management. However, the cost-effectiveness of using them for managing patients with hypertension remains inconclusive. Further research is required to understand the effectiveness and cost-effectiveness in the real-world setting. The Primary Technology-Enhanced Care for Hypertension (PTEC-HT) scaling program, a telehealth intervention for hypertension management, is currently being scaled nationwide in Singapore. The program comprises remote blood pressure (BP) monitoring at home, health care team support through teleconsultations, and in-app support with a digital chatbot. This study aimed to evaluate the program's effectiveness and cost-effectiveness. For patients under the PTEC-HT scaling program, BP readings over 6 months and 12 months, age, and gender were collected within the program. Health care use, health care cost, and patient ethnicity were extracted from the National Healthcare Group Polyclinics. For patients in the usual care group, demographic information, clinical data, health care use, and health care costs were extracted from the national claims records. Comparing the PTEC-HT scaling program with usual care, a trial-based economic evaluation using patient-level data was conducted to examine the effectiveness and cost-effectiveness over time horizons of 6 months and 12 months. The health care system's perspective was adopted. Regression analysis and exact matching were used to control for the differences between the PTEC-HT group and the usual care group. For the 6-month analysis, 427 patients were included in the PTEC-HT group, and 64,679 patients were included in the usual care group. For the 12-month analysis, 338 patients were included in the PTEC-HT group, and 7324 patients were included in the usual care group. Using exact matching plus regression, in the 6-month analysis, the probability of having controlled BP was 13.5% (95% CI 6.3%-20.7%) higher for the PTEC-HT group compared to the usual care group. In the 12-month analysis, the probability of having controlled BP was 16% (95% CI 10.7%-21.3%) higher for the PTEC-HT group. Without considering the cost of the BP machine and program maintenance cost, the direct medical cost was S $57.7 (95% CI 54.4-61.0; a currency exchange rate of S $1=US $0.74 was applicable;) lower per patient for the PTEC-HT group in the 6-month analysis and S $170.9 (95% CI 151.9-189.9) lower per patient for the PTEC-HT group in the 12-month analysis. With the cost of the BP machine and program maintenance considered, compared to usual care, the PTEC-HT program reached breakeven at around the sixth month and saved S $52.6 (95% CI 33.6-71.6) per patient at the 12th month. Implemented in a real-world setting in Singapore, our study showed that the PTEC-HT scaling program is more effective in controlling BP status with lower cost compared to the usual care over 12 months.