Worst-Case Analysis of Electrical and Electronic Equipment via Affine Arithmetic

In the design and fabrication process of electronic equipment, there are many unkown parameters which significantly affect the product performance. Some uncertainties are due to manufacturing process fluctuations, while others due to the environment such as operating temperature, voltage, and various ambient aging stressors. It is desirable to consider these uncertainties to ensure product performance, improve yield, and reduce design cost. Since direct electromagnetic compatibility measurements impact on both cost and time-to-market, there has been a growing demand for the availability of tools enabling the simulation of electrical and electronic equipment with the inclusion of the effects of system uncertainties. In this framework, the assessment of device response is no longer regarded as deterministic but as a random process. It is traditionally analyzed using the Monte Carlo or other sampling-based methods. The drawback of the above methods is large number of required samples to converge, which are time-consuming for practical applications. As an alternative, the inherent worst-case approaches such as interval analysis directly provide an estimation of the true bounds of the responses. However, such approaches might provide unnecessarily strict margins, which are very unlikely to occur. A recent technique, affine arithmetic, advances the interval based methods by means of handling correlated intervals. However, it still leads to over-conservatism due to the inability of considering probability information. The objective of this thesis is to improve the accuracy of the affine arithmetic and broaden its application in frequency-domain analysis. We first extend the existing literature results to the efficient time-domain analysis of lumped circuits considering the uncertainties. Then we provide an extension of the basic affine arithmetic to the frequency-domain simulation of circuits. Classical tools for circuit analysis are used within a modified affine framework accounting for complex algebra and uncertainty interval partitioning for the accurate and efficient computation of the worst case bounds of the responses of both lumped and distributed circuits. The performance of the proposed approach is investigated through extensive simulations in several case studies. The simulation results are compared with the Monte Carlo method in terms of both simulation time and accuracy

How affine arithmetic helps beat uncertainties in electrical systems

The ever-increasing impact of uncertainties in electronic circuits and systems is requiring the development of robust design tools capable of taking this inherent variability into account. Due to the computational inefficiency of repeated design trials, there has been a growing demand for smart simulation tools that can inherently and effectively capture the results of parameter variations on the system responses. To improve product performance, improve yield and reduce design cost, it is particularly relevant for the designer to be able to estimate worst-case responses. Within this framework, the article addresses the worst-case simulation of lumped and distributed electrical circuits. The application of interval-based methods, like interval analysis, Taylor models and affine arithmetic, is discussed and compared. The article reviews in particular the application of the affine arithmetic to complex algebra and fundamental matrix operations for the numerical frequency-domain simulation. A comprehensive and unambiguous discussion appears in fact to be missing in the available literature. The affine arithmetic turns out to be accurate and more efficient than traditional solutions based on Monte Carlo analysis. A selection of relevant examples, ranging from linear lumped circuits to distributed transmission-line structures, is used to illustrate this technique

Circular RNA Expression Profiling Identifies Prostate Cancer- Specific circRNAs in Prostate Cancer

Background/Aims: Prostate cancer (PCa) is one of the main cancers that damage males’ health severely with high morbidity and mortality, but there is still no ideal molecular marker for the diagnosis and prognosis of prostate cancer. Methods: To determine whether the differentially expressed circRNAs in prostate cancer can serve as novel biomarkers for prostate cancer diagnosis, we screened differentially expressed circRNAs using SBC-ceRNA array in 4 pairs of prostate tumor and paracancerous tissues. A circRNA-miRNA-mRNA regulatory network for the differential circRNAs and their host genes was constructed by Cytoscape3.5.1 software. Quantitative real-time polymerase chain reaction analysis (qRT-PCR) was performed to confirm the microarray data. Results: We found 1021 differentially expressed circRNAs in PCa tumor using SBC-ceRNA array and confirmed the expression of circ_0057558, circ_0062019 and SLC19A1 in PCa cell lines and tumor tissues through qRT-PCR analysis. We demonstrated that combination of PSA level and two differentially expressed circRNAs showed significantly increased AUC, sensitivity and specificity (0.938, 84.5% and 90.9%, respectively) than PSA alone (AUC of serum PSA was 0.854). Moreover, circ_0057558 was correlated positively with total cholesterol. The functional network of circRNA-miRNA-mRNA analysis showed that circ_0057558 and circ_0034467 regulated miR-6884, and circ_0062019 and circ_0060325 regulated miR-5008. Conclusion: Our results demonstrated that differentially expressed circRNAs (circ_0062019 and circ_0057558) and host gene SLC19A1 of circ_0062019 could be used as potential novel biomarkers for prostate cancer

Intra-Cavity Tm:YAG-Ho:GdVO₄ Laser with near Diffraction Limited Beam Quality

In this study, an Er:YAG laser pumped intra-cavity Tm:YAG-Ho:GdVO4 laser was built and debuted at room temperature. At an incident pump power of 9.2 W, this laser obtained a maximum output power of 1.6 W with a slope efficiency of 28.0%. Additionally, the M2 factors at the maximum output power were measured to be 1.06 and 1.03 in the x and y directions, respectively. The results showed that the intra-cavity pumping method of combining thulium and holmium crystals as the gain medium was an effective way to obtain a 2 μm laser with near diffraction limited beam quality

Intra-Cavity Tm:YAG-Ho:GdVO4 Laser with near Diffraction Limited Beam Quality

In this study, an Er:YAG laser pumped intra-cavity Tm:YAG-Ho:GdVO4 laser was built and debuted at room temperature. At an incident pump power of 9.2 W, this laser obtained a maximum output power of 1.6 W with a slope efficiency of 28.0%. Additionally, the M2 factors at the maximum output power were measured to be 1.06 and 1.03 in the x and y directions, respectively. The results showed that the intra-cavity pumping method of combining thulium and holmium crystals as the gain medium was an effective way to obtain a 2 μm laser with near diffraction limited beam quality

Graphene Passively Q-Switched Nd:YAG Laser by 885 nm Laser Diode Resonant Pumping

A graphene passively Q-switched Nd:YAG laser experienced resonant pumping by an 885 nm laser diode (LD), as demonstrated in this paper. In the continuous-wave operation, the maximum average output power was up to 1.8 W with the absorbed pump power being 11.7 W, and the slope efficiency was 51.2%. In the Q-switching operation, the maximum average output power was up to 639 mW with a pulse width of 2.06 μs at the repetition frequency of 102.7 kHz, while the slope efficiency and the beam quality factor M2 were 25.3% and 1.25, respectively

Broadband Circularly Polarized Conical Corrugated Horn Antenna Using a Dielectric Circular Polarizer

In this paper, a broadband left-handed circularly polarized (LHCP) corrugated horn antenna using a dielectric circular polarizer is proposed. Circularly polarized (CP) waves are generated by inserting an improved dovetail-shaped dielectric plate into the circular waveguide. Compared with the traditional dovetail-shaped circular polarizer, the proposed improved dovetail-shaped circular polarizer has a wider impedance bandwidth and 3 dB axial ratio bandwidth. A substrate-integrated waveguide (SIW) structure is designed as a wall to eliminate the influence of fixed grooves on the circular polarizer. The simulated reflection coefficient of the dielectric plate circular polarizer is less than −20 dB in the frequency band from 17.57 to 33.25 GHz. Then, a conical corrugated horn antenna with five corrugations and a four-level metal stepped rectangular-circular waveguide converter are designed and optimized. The simulated −10 dB impedance and 3 dB axial ratio (AR) bandwidths of the circularly polarized horn antenna integrated with the polarizer are 61% (17.1–32.8 GHz) and 60.9% (17.76–33.32 GHz), respectively. The simulated peak gain is 17.34 dBic. The measured −10 dB impedance is 52.7% (17.2–27.5 GHz)

Worst-Case analysis of electrical and electronic equipment via affine arithmetic

This paper proposes to generate a smart tool that can inherently and effectively capture the results of parameter variations on the system responses of lumped and distributed electrical circuits. This methodology leverages the so-called affine arithmetic and represents parameter-dependent responses in terms of a multivariate polynomial. The affine representation is propagated from input parameters to circuit responses through a suitable redefinition of the basic operations, such as addition, multiplication or matrix inversion, that are involved in the circuit solution. The proposed framework is applied to the frequency-domain analysis of switching converters, and it turns out to be accurate and more efficient than traditional solutions based on Monte Carlo analysis