Performance Comparison of the SGM and the SCM in EMC Simulation

Uncertainty analysis methods are widely used in today’s Electromagnetic Compatibility (EMC) simulations in order to take account of the non-ideality and unpredictability in reality and improve the reliability of simulation results. The Stochastic Galerkin Method (SGM) and the Stochastic Collocation Method (SCM), both based on the generalized Polynomial Chaos (gPC) expansion theory, have become two prevailing types of uncertainty analysis methods thanks to their high accuracy and high computational efficiency. This paper, by using the Feature Selective Validation (FSV) method, presents the quantitative accuracy comparison between the foregoing two methods, with the commonly used Monte Carlo Method (MCM) used as the comparison reference. This paper also introduces SCM into the CST software simulation as an example of performing uncertainty analysis. The advantages and limitations of SGM and SCM are discussed in detail in this paper. Finally, the strategy of how to choose between SGM, SCM, and MCM under different situations is proposed in the conclusion section

Milestones in Autonomous Driving and Intelligent Vehicles Part II: Perception and Planning

Growing interest in autonomous driving (AD) and intelligent vehicles (IVs) is fueled by their promise for enhanced safety, efficiency, and economic benefits. While previous surveys have captured progress in this field, a comprehensive and forward-looking summary is needed. Our work fills this gap through three distinct articles. The first part, a "Survey of Surveys" (SoS), outlines the history, surveys, ethics, and future directions of AD and IV technologies. The second part, "Milestones in Autonomous Driving and Intelligent Vehicles Part I: Control, Computing System Design, Communication, HD Map, Testing, and Human Behaviors" delves into the development of control, computing system, communication, HD map, testing, and human behaviors in IVs. This part, the third part, reviews perception and planning in the context of IVs. Aiming to provide a comprehensive overview of the latest advancements in AD and IVs, this work caters to both newcomers and seasoned researchers. By integrating the SoS and Part I, we offer unique insights and strive to serve as a bridge between past achievements and future possibilities in this dynamic field.Comment: 17pages, 6figures. IEEE Transactions on Systems, Man, and Cybernetics: System

The Structural, Electronic, and Optical Properties of Ge/Si Quantum Wells: Lasing at a Wavelength of 1550 nm

The realization of a fully integrated group IV electrically driven laser at room temperature is an essential issue to be solved. We introduced a novel group IV side-emitting laser at a wavelength of 1550 nm based on a 3-layer Ge/Si quantum well (QW). By designing this scheme, we showed that the structural, electronic, and optical properties are excited for lasing at 1550 nm. The preliminary results show that the device can produce a good light spot shape convenient for direct coupling with the waveguide and single-mode light emission. The laser luminous power can reach up to 2.32 mW at a wavelength of 1550 nm with a 300-mA current. Moreover, at room temperature (300 K), the laser can maintain maximum light power and an ideal wavelength (1550 nm). Thus, this study provides a novel approach to reliable, efficient electrically pumped silicon-based lasers

Milestones in autonomous driving and intelligent vehicles: survey of surveys

Interest in autonomous driving (AD) and intelligent vehicles (IVs) is growing at a rapid pace due to the convenience, safety, and economic benefits. Although a number of surveys have reviewed research achievements in this field, they are still limited in specific tasks, lack of systematic summary and research directions in the future. Here we propose a Survey of Surveys (SoS) for total technologies of AD and IVs that reviews the history, summarizes the milestones, and provides the perspectives, ethics, and future research directions. To our knowledge, this article is the first SoS with milestones in AD and IVs, which constitutes our complete research work together with two other technical surveys. We anticipate that this article will bring novel and diverse insights to researchers and abecedarians, and serve as a bridge between past and future

Genetic variants in the TIRAP gene are associated with increased risk of sepsis-associated acute lung injury

<p>Abstract</p> <p>Background</p> <p>Toll like receptors (TLRs) signaling pathways, including the adaptor protein Mal encoded by the TIRAP gene, play a central role in the development of acute lung injury (ALI). Recently, the <it>TIRAP </it>variants have been described association with susceptibility to inflammatory diseases. The aim of this study was to investigate whether genetic variants in <it>TIRAP </it>are associated with the development of ALI.</p> <p>Methods</p> <p>A case-control collection from Han Chinese of 298 healthy subjects, 278 sepsis-associated ALI and 288 sepsis alone patients were included. Three tag single nucleotide polymorphisms (SNPs) of the TIRAP gene and two additional SNPs that have previously showed association with susceptibility to other inflammatory diseases were genotyped by direct sequencing. The differences of allele, genotype and haplotype frequencies were evaluated between three groups.</p> <p>Results</p> <p>The minor allele frequencies of both rs595209 and rs8177375 were significantly increased in ALI patients compared with both healthy subjects (odds ratio (OR) = 1.47, 95% confidence interval (CI):1.15-1.88, P = 0.0027 and OR = 1.97, 95% CI: (1.38-2.80), P = 0.0001, respectively) and sepsis alone patients (OR = 1.44, 95% CI: 1.12-1.85, P = 0.0041 and OR = 1.82, 95% CI: 1.28-2.57, P = 0.00079, respectively). Haplotype consisting of these two associated SNPs strengthened the association with ALI susceptibility. The frequency of haplotype AG (rs595209A, rs8177375G) in the ALI samples was significantly higher than that in the healthy control group (OR = 2.13, 95% CI: 1.46-3.09, P = 0.00006) and the sepsis alone group (OR = 2.24, 95% CI: 1.52-3.29, P = 0.00003). Carriers of the haplotype CA (rs595209C, rs8177375A) had a lower risk for ALI compared with healthy control group (OR = 0.69, 95% CI: 0.54-0.88, P = 0.0003) and sepsis alone group (OR = 0.71, 95% CI: 0.55-0.91, P = 0.0006). These associations remained significant after adjustment for covariates in multiple logistic regression analysis and for multiple comparisons.</p> <p>Conclusions</p> <p>These results indicated that genetic variants in the TIRAP gene might be associated with susceptibility to sepsis-associated ALI in Han Chinese population. However, the association needs to be replicated in independent studies.</p

Effect of Carbon Number Distribution of Wax on the Yield Stress of Waxy Oil Gels

Wax deposition is one of the most important problems in flow assurance of petroleum pipelines. Pigs are commonly employed for the removal of wax deposit (actually a wax–oil gel consisting of liquid oil and solid wax particles) on the pipe wall. Understanding of the wax deposit strength, which may be a function of the carbon number distribution of wax, assists in preventing the pig from getting stuck in the pipeline. This study focuses on the effect of the carbon number distribution of wax on the yield stress of waxy oil gels. Waxes with different carbon number distribution were dissolved into a crude oil to prepare the model oils. The vane method was used to determine the yield stress of waxy oil gels formed under quiescent or shear conditions, in which an applied shear stress was maintained during the process of cooling and isothermal holding. The results showed that the yield stresses dramatically decrease with increase of average carbon number of wax regardless of the quiescent or shear conditions. However, the applied shear stress has little effect on the yield stress of the wax–oil gel 12.5% W1 + oil-A and no effect on the yield stresses of 12.5% W2 + oil-A and 12.5% W3 + oil-A. Under quiescent conditions, the changing rate of the yield stress with respect to the solid wax content reduces as the average carbon number of wax increases. The morphology and structure of the wax crystals were also observed using optical microscopy. Microscopic observation indicated that the average size and boundary fractal dimension of the wax crystals decrease but the aspect ratio increases with the increase of the average carbon number of wax

Thermal, Macroscopic, and Microscopic Characteristics of Wax Deposits in Field Pipelines

Wax deposition is an important issue in crude oil transportation. Understanding the deposit properties assists in making a suitable schedule for removing wax deposits. However, there was little work published on the nature of wax deposits in field pipelines. This study focuses on the thermal, macroscopic, and microscopic characteristics of wax deposits obtained from the field pipelines. First, differential scanning calorimetry (DSC) was used to investigate the thermal properties of wax deposits and crude oils. The results showed that the wax appearance temperature (WAT) and wax content of wax deposits is much higher than that of crude oils, and both of two parameters increase with the increasing radial distances. For all deposits, the precipitated wax concentration increases significantly with the decreasing temperature near the WAT, while it almost increases linearly when the temperature decreases about 25 °C below the WAT. Based on DSC results, a correlation between the solid wax content and wax content and temperature was developed. Verification experiments showed that this correlation calculates the solid wax content with the absolute deviation within ±4% and the average relative deviation of 3.8%. Second, the macroscopic structure of wax deposits was visually observed. The yield stresses were also determined using the vane method. The results showed that the loose structure of the original deposits could result in small values of yield stresses, and the yield stresses increase as the radial distances increase. Third, the optical microscopy was used to observe the microscopic characteristics of wax crystals. The average size, aspect ratio, and boundary fractal dimension of wax crystals in deposits vary in the ranges 9.1–14.3 μm², 1.55–1.77, and 1.13–1.20, respectively. The average size and boundary fractal dimension of wax crystals in deposits are higher than that of the crystals in crude oils

Terahertz Rectangular Waveguides by UV-LIGA with Megasonic Agitation

This paper researches the fabrication of a WR2.8 terahertz rectangular waveguide operating at the frequency ranging from 260 GHz to 400 GHz via UV-LIGA technology (UV-lithography, electroplating, and molding). In the process, megasonic agitation is applied to improve the mechanical properties and internal surface roughness of the WR2.8 rectangular waveguide. The effects of process parameters on the properties of structures are discussed, and optimized parameters are obtained to achieve accurate geometry dimensions. In addition, the highly crosslinked SU-8 is reliably removed from structures without damage through a synthesis method. The accuracy of the height and width of the WR2.8 rectangular waveguide is 5 &micro;m and 2 &micro;m, respectively, and the measured internal surface roughness is 79.6 nm. Moreover, experimental measurements and numerical simulations of the waveguide are conducted, and the difference between the two is also highlighted

A Dimension-reduced Sparse Grid Strategy for Stochastic Collocation Method in EMC Software

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Stochastic Collocation Method (SCM), a prevailing uncertainty analysis method, has been successfully implemented in Electromagnetic Compatibility (EMC) simulation, especially in EMC commercial software. However, the “curse of dimensionality” problem (dimensionality means the number of uncertain variables) limits the application of the SCM. This paper proposes a novel sparse grid strategy in order to improve the computational efficiency of the SCM, especially in high dimensionality case. In the proposed strategy, it is revealed that the number of the collocation points is in proportion to the dimensionality. By simulating two shielding effectiveness analysis examples in CST software, the feasibility of the proposed method can be presented clearly, with the help of the Feature Selective Validation method