General-Sum Finite-Horizon Potential Linear-Quadratic Games with a Convergent Policy

This paper explores the potential game properties of the non-cooperative finite-horizon general-sum Linear Quadratic (LQ) game. We show that a general LQ game is potential if and only if it is an identical interest game. Based on this result, we restrict the class of LQ games to those with decoupled agent dynamics and information structure. For this restricted subset, we derive conditions under which the game is potential. Furthermore, for the identified subset, we prove the convergence of policy gradient to a Nash equilibrium.Comment: Submitted to CDC Conferenc

Deep level investigation of InGaAs on InP layer

Deep level traps in lattice-matched In0.47Ga0.53As epitaxial layers grown by MBE on InP substrates have been studied by Deep Level Transient Spectroscopy (DLTS) on Al2O3/InGaAs Metal-Oxide-Semiconductor (MOS) capacitors. The impact of different surface passivation steps and a post-gate-deposition Forming Gas Annealing (FGA) has been studied. It is shown that spectra are dominated by a near mid gap electron trap in the depletion region, with activation energy in the range 0.37 eV to 0.42 eV. At the same time, a broad background distribution of interface states is found as well, which is significantly reduced by the FGA. Detailed carrier trapping studies have been carried out to identify the origin of the grown-in electron traps, which are shown to be of point defect behavior

The predictive value of C-reactive protein (CRP) and procalcitonin chemical biomarkers in the premature diagnosis of infection in brain ischemic stroke

BACKGROUND: The infections are common complications after the ischemic stroke. The aim of this study was to evaluate the anticipatory value of C-reactive protein (CRP) and procalcitonin (PCT) biomarkers in diagnosis of stroke-induced infection.METHODS: In the current prospective study, 184 patients with cerebral ischemia were enrolled. Serum samples were obtained from patients. The CRP and PCT, white blood cells (WBCs) and monocytes, and final infections were evaluated.RESULTS: In the first 72 hours, the analysis for CRP revealed that the sensitivity was 41.60%, the specificity was 100%, positive predictive value (PPV) was 100%, and negative predictive value (NPV) was 82.90%. PCT showed that the sensitivity was 85.41%, the specificity was 98.54%, PPV was 95.34%, and NPV was 95%.CONCLUSION: According to our findings, the evaluation of CRP and PCT with simultaneous clinical observation could be considered as a good step in start of antibiotic therapy

An investigation on border traps in III-V MOSFETs with an In0.53Ga0.47As channel

Continuing CMOS performance scaling requires developing MOSFETs of high-mobility semiconductors and InGaAs is a strong candidate for n-channel. InGaAs MOSFETs, however, suffer from high densities of border traps, and their origin and impact on device characteristics are poorly understood at present. In this paper, the border traps in nMOSFETs with an In0.53Ga0.47As channel and Al2O3 gate oxide are investigated using the discharging-based energy profiling technique. By analyzing the trap energy distributions after charging under different gate biases, two types of border traps together with their energy distributions are identified. Their different dependences on temperature and charging time support that they have different physical origins. The impact of channel thickness on them is also discussed. Identifying and understanding these different types of border traps can assist in the future process optimization. Moreover, border trap study can yield crucial information for long-term reliability modeling and device timeto-failure projection

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic

Design, Fabrication and Interface Characterization of High Mobility InGaAs Channel MOS(FET) Devices (Ontwerp, fabricatie en interface karakterisatie van hoge mobiliteit InGaAs kanaal MOS transistoren)

The state-of-the-art knowledge about the passivation as well as the historical advancements for realizing III-V channel MOSFETs are discussed.Starting with MOSCAPs being the simplest electrically measurable gate stack devices, the influence of various chemical and thermal treatments on the electrical characteristics of the MOSCAPs were investigated. Besides slightly reduced accumulation frequency dispersion in the C-V response of the n-type MOSCAPs, sulfur passivation of the surface through aqueous (NH4)2S treatment (being a very well-known III-V surface passivation scheme) was found to even degrade the interface state density compared to a simple HCl surface treatment. NH4OH treatment of the surface, another reported passivating solution, did not improve the interface characteristics neither. Issues influencing the quantification of the interface state density in the InGaAs MOSCAP were discussed.A fabrication process flow was developed to make long channel MOSFET transistors in order to study the influence of the surface treatments on the transistor characteristics. A MOSFET platform also mitigates part of the quantification issues associated with the interface state density. In the effort to make such MOSFET devices, a digital etch process capable of controlled, precise and smooth etching of the InGaAs material was also developed and characterized. Except for the epitaxial growth of the layers, developments associated with the MOSFET processing flow as well as the complete fabrication of the MOSFET devices investigated in this thesis was performed as part of the PhD work.Electrical characterization of the fabricated InGaAs channel MOSFETs demonstrated the importance of hydrogen annealing in improving the interface properties by reducing the interface state density from above 4×1013 cm−2eV−1 to about 4×1012 cm−2eV−1 in the midgap of InGaAs. Further investigations on sulfur passivated MOSFETs revealed that sulfur treated devices exhibit 3 to 4 times higher drive current than the HCl treated devices. The degraded interface state density after sulfur passivation translated into degraded sub-threshold characteristics of the sulfur treated MOSFETs. The higher drive current of the sulfur treated MOSFET despite its higher interface state density compared to the HCl treated device confirms the donor-like nature of the midgap interface states making them neutral during the on-state operation of the device.A complete characterization of the bulk oxide defects applying the TSCIS oxide trap characterization method revealed that the defect density inside the gate oxide (here Al2O3) is significantly influenced by the type of the surface chemical treatment prior to the gate oxide deposition. Sulfur passivation of the surface was found to decrease the density of the oxide traps by a factor of 3 to 4 compared to that of the device with HCl surface treatment. The energetic position of these oxide traps was found to be at the conduction band edge of InGaAs, therefore these traps are accessible to the electrons of the conduction band of InGaAs. Consequently, the increase in the drive current of the device with sulfur passivation over the HCl treated one was attributed to the increased electron mobility inside the channel of the device through the reduction of Coulomb scattering of the current carriers due to the charged traps inside the oxide.TOFSIMS characterization of the bulk of the Al2O3 revealed significantly higher (about 4 times) indium concentration inside the oxide with HCl surface pretreatment compared to that of the oxide with (NH4)2S surface pretreatment. Based on the results, sulfur treatment reduces the indium diffusion/segregation from the InGaAs into the Al2O3 layer. Correlating the TOFSIMS data and the TSCIS results suggests indium as a possible origin of traps inside the oxide.A new type of sulfur treatment of the InGaAs surface using the vapor from the aqueous (NH4)2S solution was investigated and MOSFET characteristics identical to the aqueous (NH4)2S treated MOSFETs were measured. Finally, the influence of the surface potential fluctuations on the simulated C-V response of the p-type InGaAs MOSCAP devices was explored. It was found that the observed stretch out in the experimental C-V characteristic of the p-type InGaAs MOSCAPs as well as their large accumulation capacitance frequency dispersion can be originating from the surface potential fluctuations caused by the charged interface traps. It was also found that the surface potential fluctuations can have a significant impact on the conductance characteristic of the devices. The surface potential fluctuations can limit the measurable Dit energy range within the bandgap of the semiconductor and neglecting the surface potential fluctuations results in underestimation of the interface state density.Introduction 1.1 Goal and approach of this study 2 Literature review 2.1 Interface states and surface passivation 2.1.1 Interface state models 2.1.2 In situ oxide deposition 2.1.3 Atomic Layer Deposition (ALD) self-cleaning effect 2.1.4 Density functional theory (DFT) simulations 2.1.5 Sulfur passivation 2.1.6 Oxide traps 2.2 GaAs 2.3 InGaAs 2.4 State-of-the-art 3 Experimental techniques 3.1 Device fabrication flows 3.1.1 MOSCAP fabrication flow 3.1.1.1 Surface treatment 3.1.2 MOSFET fabrication flow 3.1.3 Source/drain isolation etch (gate recess) 3.1.3.1 Using an etch-stop layer 3.1.3.2 Timed etching of n+InGaAs 3.1.3.3 Digital etching 3.1.4 Deposition tools 3.1.4.1 Atomic Layer Deposition (ALD) 3.1.4.2 Molecular Beam Epitaxy (MBE) 3.1.4.3 Metal Organic Chemical Vapor Deposition (MOCVD) 3.2 Electrical characterization methods 3.2.1 The conductance method and Dit extraction 3.2.1.1 Difficulties in Dit quantification 3.2.2 Trap Spectroscopy by Charge Injection and Sensing (TSCIS) 3.3 Physical characterization tools 3.3.1 X-ray Photoelectron Spectroscopy (XPS) 3.3.2 Time Of Flight Secondary Ion Mass Spectroscopy (TOFSIMS) 4 InGaAs MOSCAP characterization 4.1 Electrical characterization 4.1.1 HCl versus (NH4)2S treatment 4.1.2 NH4OH treatment 4.1.3 Impact of FGA 4.2 Physical characterization 4.2.2 The native oxide growth rate 4.3 Conclusions 5 InGaAs MOSFET characterization 5.1 Impact of FGA on MOSFET characteristics 5.1.1 C-V characterization 5.1.2 I-V characterization 5.2 Impact of the surface pretreatment 5.2.1 C-V characterization 5.2.2 I-V characterization 5.3 Conclusions 6 Ammonium sulfide vapor (ASV) surface treatment 6.1 Device description 6.2 Electrical characterization 6.2.1 C-V characterization 6.2.2 I-V characterization 6.2.2.1 Off-state characteristics 6.2.2.2 On-state characteristics 6.3 XPS characterization 6.4 Conclusions 7 Oxide traps 7.1 Device Characterization 7.2 Conclusions 8 Understanding the C-V response of the p-type InGaAs MOSCAP 8.1 Influence of the surface potential fluctuations on the C-V characteristic 8.2 Influence of the surface potential fluctuations on the conductance characteristic 8.2.1 Dit extraction in presence of surface potential fluctuations 8.3 Conclusions 9 Conclusions 9.1 Future work Bibliography List of publications Curriculum Vitaenrpages: 140status: publishe

Convergence to Nash in the potential Linear Quadratic games and accelerated learning in games

Game theory and online optimization have a close relationship with each other. In some literature, online optimization has been employed for solving game theory problems. Many accelerated algorithms are proposed for offline optimization problems. However, to the best of our knowledge, there is not enough work done to accelerate zero-order online optimization. The goal is to propose a Nesterov accelerated online algorithm with the hope that it will converge to the Nash, with a fast convergence rate in Cournot games and Quadratic games. It is desired that this online algorithm also minimize the regret of a sequence of functions for both zero-order and first-order feedback. In potential Linear Quadratic (LQ) games, we also study the convergence of the policy gradient algorithms, a class of conventional reinforcement learning methods. LQ games have applications in engineering. It has been shown that using policy gradient algorithms by agents does not guarantee convergence to the Nash equilibrium. However, in the LQR problem, which is essentially a one-player LQ game, the policy gradient converges to the optimum. In this work, we show that using policy gradient algorithms leads to convergence to Nash equilibrium in potential LQ games. Additionally, we identify the characteristics of potential games in both open-loop and closed-loop settings. We will demonstrate that the class of closed-loop potential games is generally trivial, and if we put restrictions on players' actions, we can have non-trivial potential games too.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat

Effect of Intranasal Mupirocin in Preventing Post-operative Infection after Open Heart Surgery

Background and purpose: Surgical site infection is one of the most important complications of cardiac surgery, and in 50% of cases, is caused by Staphylococcus species. This study evaluated the effectiveness of intranasal administration of mupirocin in reducing nasal bacterial colonization, mediastinal, sternal, pulmonary, and skin infections after open-heart surgery. Materials and methods: This descriptive study investigated the records of patients who developed post-operative infection following open-heart surgery in Sari Fatemeh Zahra Hospital during 2011-2015. Treatments were done in two different periods: first period from 2011 to September 2013 and the second period from October 2013 to March 2015. In second course, intra-nasal administration of mupirocin was done to all patients, as a routine hospital care. Then, the incidence of post-operative infection, type, and site of infection were compared. Results: Frequency of infection was 78.26% in the group that had recieved mupirocin and 46.29% in the group that had not received mupirocin. The rate of surgical site infection in the group that had received mupirocin was 21.74% and in the group without mupirocin it was 53.71% (P= 0.000). We observed significant reductions in the incidence of superficial infection of the incision (1.85% in the group that was given mupirocin vs. 10.9% in the group without mupirocin, P= 0.009), foot superficial infections (23.1% in the group that had received mupirocin vs. 27.7% in the group without mupirocin, P= 037), and deep soft tissue infection of foot (10.3% in the group that had received mupirocin and 18.18% in the group that had nor received mupirocin). Conclusion: Intra-nasal administration of mupirocin could prevent cutaneous infections after cardiac surgery and also reduce hospital length of stay

Chest CT Scan Findings and Severity of Disease in Patients with COVID-19 Admitted to Qaemshahr Razi Hospital, 2020-2021

Background and purpose: Timely diagnosis of patients with suspected COVID-19 using chest Computed tomography (CT) scan is of great benefit in reducing the severity of the disease. Previous studies did not address this issue, so, this study aimed to investigate the findings of chest CT scan images and the severity of lung involvement in patients hospitalized with COVID-19. Materials and methods: We performed a retrospective descriptive-analytical study in all patients admitted to Qaemshahr Razi Hospital with symptoms of COVID-19 and positive RT-PCR test results in 2019-2020. All chest scans were reviewed and reported by a radiologist. Data were analyzed using Chi-square and t-test. Results: The patients (n= 666) included 51.36% women and 48.64% men. The mean age of patients was 54.06±16.55 years. Moderate lung involvement was more common and ground-glass opacity (GGO) was the highest encountered pattern (39.33%). Also, in severe lung involvement, GGO pattern was found to be more prevalent (22.37%). Minimal lung involvement (0-25%), moderate lung involvement (25-50%), and sever lung involvement (> 75%) were seen in 6.75%, 22.29%, and 20.27%, respectively. Most of the patients were highly suggestive of COVID-19 and moderate lung involvement (45.97%) was found to be higher in this condition. No significant difference was seen between the extent of lung involvement in patients studied (P= 0.535). Conclusion: The CT scan results in our patients in Mazandaran province with COVID-19 showed primarily GGO followed by consolidation and crazy paving patterns

Near Hysteresis-Free Negative Capacitance InGaAs Tunnel FETs with Enhanced Digital and Analog Figures of Merit below V-DD=400mV

We report the universal boosting impact of a true negative capacitance (NC) effect on digital and analog performances of Tunnel FETs (TFETs), mirrored for the first time in near hysteresis-free experiments and exploiting the S-shaped polarization characteristics. Well behaved InGaAs TFETs with a minimum swing of 55 mV/dec at room temperature are combined with high-quality single crystalline PZT capacitors, placed in series with the gate. When fully satisfying the exact NC matching conditions by a single crystalline ferroelectric that can perform a mono-domain state, a hysteresis-free (sub-10 mV over 4 decades of current) NC-TFET with a sub-thermionic swing and an SS. of 40 mV/dec is demonstrated. In other devices, improvement in the subthreshold swing, down to 30 mV/dec, and analog current efficiency factor, up to 180 V-1, are achieved in NC-TFETs with a hysteresis as small as 30 mV. Importantly, the I-60 FoM of the TFET is improved up to 2 orders of magnitude. The supply voltage is thereby reduced by 50%, down to 300 mV, providing the same drive current. Our results show that NC can open a new direction as a universal performance booster in the FET design by significantly improving the low I-60 and low overdrive of TFETs