Assessing the energy transition in China towards carbon neutrality with a probabilistic framework

A profound transformation of China’s energy system is required to achieve carbon neutrality. Here, we couple Monte Carlo analysis with a bottom-up energy-environment-economy model to generate 3,000 cases with different carbon peak times, technological evolution pathways and cumulative carbon budgets. The results show that if emissions peak in 2025, the carbon neutrality goal calls for a 45–62% electrification rate, 47–78% renewable energy in primary energy supply, 5.2–7.9 TW of solar and wind power, 1.5–2.7 PWh of energy storage usage and 64–1,649 MtCO2 of negative emissions, and synergistically reducing approximately 80% of local air pollutants compared to the present level in 2050. The emission peak time and cumulative carbon budget have significant impacts on the decarbonization pathways, technology choices, and transition costs. Early peaking reduces welfare losses and prevents overreliance on carbon removal technologies. Technology breakthroughs, production and consumption pattern changes, and policy enhancement are urgently required to achieve carbon neutrality.

A Monte Carlo Analysis of Actual Maximum Exposure From a 5G Millimeter-Wave Base Station Antenna for EMF Compliance Assessments

International radio frequency (RF) electromagnetic field (EMF) exposure assessment standards and regulatory bodies have developed methods and specified requirements to assess the actual maximum RF EMF exposure from radio base stations enabling massive multiple-input multiple-output (MIMO) and beamforming. Such techniques are based on the applications of power reduction factors (PRFs), which lead to more realistic, albeit conservative, exposure assessments. In this study, the actual maximum EMF exposure and the corresponding PRFs are computed for a millimeter-wave radio base station array antenna. The computed incident power densities based on near-field and far-field approaches are derived using a Monte Carlo analysis. The results show that the actual maximum exposure is well below the theoretical maximum, and the PRFs similar to those applicable for massive MIMO radio base stations operating below 6 GHz are also applicable for millimeter-wave frequencies. Despite the very low power levels that currently characterize millimeter-wave radio base stations, using the far-field approach can also guarantee the conservativeness of the PRFs used to assess the actual maximum exposure close to the antenna.

Uncertainty Propagation for Inertial Navigation with Coning, Sculling, and Scrolling Corrections

This paper investigates the propagation of estimation errors through a common coning, sculling, and scrolling architecture used in modern-day inertial navigation systems. Coning, sculling, and scrolling corrections often have an unaccounted for effect on the error statistics of inertial measurements used to describe the state and uncertainty propagation for position, velocity, and attitude estimates. Through the development of an error analysis for a set of coning, sculling, and scrolling algorithms, mappings of the measurement and estimation errors through the correction term are adaptively generated. Using the developed mappings, an efficient and consistent propagation of the state and uncertainty, within the multiplicative extended Kalman filter architecture, is achieved. Monte Carlo analysis is performed, and results show that the developed system has favorable attributes when compared to the traditional mechanization.

Yield Optimization using Hybrid Gaussian Process Regression and a Genetic Multi-Objective Approach

Quantification and minimization of uncertainty is an important task in the design of electromagnetic devices, which comes with high computational effort. We propose a hybrid approach combining the reliability and accuracy of a Monte Carlo analysis with the efficiency of a surrogate model based on Gaussian Process Regression. We present two optimization approaches. An adaptive Newton-MC to reduce the impact of uncertainty and a genetic multi-objective approach to optimize performance and robustness at the same time. For a dielectrical waveguide, used as a benchmark problem, the proposed methods outperform classic approaches.

Are Women Less Likely to Ask than Men Partly Because They Work Fewer Hours? A Commentary on Artz et al. (2018)

A long debate in negotiation research concerns the question of whether gender differences in the propensity to initiate negotiations, in behaviors shown during negotiations, and in negotiation performance actually exist. Whereas past negotiation research suggested that women are less likely to initiate negotiations than men, a recent study by Artz et al. (2018) seems to suggest that women are as likely as men to “ask” for higher pay. However, this finding by Artz et al. (2018) was obtained once the number of weekly hours worked was added as a covariate in the statistical analysis. Following extant work, we suggest that the number of weekly hours worked could be—and, from a theoretical stand-point, perhaps should be—considered a mediator of gender differences. Conducting a Monte Carlo analysis based on the results and statistics provided by Artz et al. (2018) also yielded empirical evidence suggesting that weekly hours could be a mediator. Thus, women may be less likely than men to ask for higher pay, among other potential reasons, because they work fewer weekly hours. Based on this alternative conceptualization of the role of weekly hours, our commentary has theoretical implications for the understanding of gender differences in the propensity to initiate negotiations and practical implications for the effective reduction of gender inequalities.

Comparison of embolization strategies for mixed plexiform and fistulous brain arteriovenous malformations: a computational model analysis of theoretical risks of nidus rupture

BackgroundHigh-flow fistulas related to plexiform nidi are found in 40% of large brain arteriovenous malformations (AVMs). Endovascular occlusion of intranidal fistulas before plexiform components is empirically considered safe, but potential ensuing dangerous re-routing of flow through plexiform vessels may in theory raise their rupture risk. It remains unclear whether it is safer to embolize plexiform or fistulous vessels initially. We used a novel biomathematical AVM model to compare theoretical hemodynamic changes and rupture risks on sequential embolizations of both types of nidus vessels.MethodsWe computationally modeled a theoretical AVM as an electrical circuit containing a nidus consisting of a massive stochastic network ensemble comprising 1000 vessels. We sampled and individually simulated 10 000 different nidus morphologies with a fistula angioarchitecturally isolated from its adjacent plexiform nidus. We used network analysis to calculate mean intravascular pressure (Pmean) and flow rate within each nidus vessel; and Monte Carlo analysis to assess overall risks of nidus rupture when simulating sequential occlusions of vessel types in all 10 000 nidi.ResultsWe consistently observed lower nidus rupture risks with initial fistula occlusion in different network morphologies. Intranidal fistula occlusion simultaneously reduced Pmean and flow rate within draining veins.ConclusionsInitial occlusion of AVM fistulas theoretically reduces downstream draining vessel hypertension and lowers the risk of rupture of an adjoining plexiform nidus component. This mitigates the theoretical concern that fistula occlusion may cause dangerous redistribution of hemodynamic forces into plexiform nidus vessels, and supports a clinical strategy favoring AVM fistula occlusion before plexiform nidus embolization.

Azure Lodging, Inc.: A Case Study on Capital Budgeting with Capital Rationing in a Service Industry Context

This case illustrates capital budgeting in a service industry context. Three features should make this case attractive to instructors. First, the firm's rationing of capital means that students must select one investment among competing investment alternatives. Second, the project involves renovation of an existing hotel. Most cases consider a business expansion where analysis involves estimation of a single series of cash flows to generate net present value (i.e., future cash flows or not). In this case, students model cash flows if the project is accepted, comparing those cash flows to a model of cash flows if the hotel continues without renovation. Third, we introduce Monte Carlo analysis, an advanced technique for assessing uncertainty. The extensive data students use in this case is from an actual hotel chain's project database. The case has been used in undergraduate and graduate managerial accounting classes.

A Low-Noise High-Gain Recycling Folded Cascode Operational Transconductance Amplifier Based on Gate Driven and Quasi-Floating Bulk Technique

Operational Transconductance Amplifier (OTA) is an important circuit block used in the design of filter, amplifiers and oscillators for various analog-mixed circuit systems. However, design of a low-noise, high-gain OTA with low-power consumption is a challenging task in CMOS technology owing to high-power requirements of OTA for emulating high gain. This paper represents the design of gate-driven quasi-floating bulk recycling folded cascode (GDQFB RFC) OTA which has been shown to provide low-noise operation, emulates high gain and draws very less power. The design utilizes the gate-driven quasi-floating bulk (GDQFB) technique on a recycling folded cascode structure, which enhances the transconductance of OTA and improves its performance. All the post-layout simulation results have been obtained in 0.18-[Formula: see text]m CMOS N-well technology using BSIM3V3 device models. The obtained results indicate very high gain of 100.4 dB, gain-bandwidth of 69[Formula: see text]kHz, phase margin of 51.9∘ with power consumption of 2.31[Formula: see text][Formula: see text]W from [Formula: see text][Formula: see text]V supply voltage. The input referred noise emulated by proposed OTA is 0.684, 0.21 and 0.0592[Formula: see text][Formula: see text]V/[Formula: see text]Hz @ 1[Formula: see text]Hz, 10[Formula: see text]Hz and 1[Formula: see text]kHz, respectively. The input common mode range and output voltage swing are found to be [Formula: see text] to 0.669[Formula: see text]V and [Formula: see text] to 0.610[Formula: see text]V, respectively. Corner simulations and Monte Carlo analysis have been performed to verify the robustness of the proposed OTA. The proposed OTA can be used in design of filters and amplifiers for bio-instruments, sensor applications, neural recording applications and human implants etc.