A Framework for Noise Analysis and Verification of Analog Circuits

Analog circuit design and verification face significant challenges due to circuit complexity and short market windows. In particular, the influence of technology parameters on circuits, noise modeling and verification still remain a priority for many applications. Noise could be due to unwanted interaction between the various circuit blocks or it could be inherited from the circuit elements. Current industrial designs rely heavily on simulation techniques, but ensuring the correctness of such designs under all circumstances usually becomes impractically expensive. In this PhD thesis, we propose a methodology for modeling and verification of analog designs in the presence of noise and process variation using run-time verification methods. Verification based on run-time techniques employs logical or statistical monitors to check if an execution (simulation) of the design model violates the design specifications (properties). In order to study the random behavior of noise, we propose an approach based on modeling the designs using stochastic differential equations (SDE) in the time domain. Then, we define assertion and statistical verification methods in a MATLAB SDE simulation framework for monitoring properties of interest in order to detect errors. In order to overcome some of the drawbacks associated with monitoring techniques, we define a pattern matching based verification method for qualitative estimation of the simulation traces. We illustrate the efficiency of the proposed methods on different benchmark circuits

Generation of energetic negative ions from clusters using intense laser fields

Intense laser fields are known to induce strong ionization in atoms. In nanoclusters, ionization is only stronger, resulting in very high charge densities that lead to Coulomb explosion and emission of accelerated highly charged ions. In such a strongly ionized system, it is neither conceivable nor intuitive that energetic negative ions can originate. Here we demonstrate that in a dense cluster ensemble, where atomic species of positive electron affinity are used, it is indeed possible to generate negative ions with energy and ion yield approaching that of positive ions. It is shown that the process behind such a strong charge reduction is extraneous to the ionization dynamics of single clusters within the focal volume. Normal and well-known charge transfer reactions are insufficient to explain the observations. Our analysis reveals the formation of a manifold of Rydberg excited clusters around the focal volume that facilitate orders of magnitudes more efficient electron transfer. This phenomenon, which involves an active role of laser-heated electrons, comprehensively explains the formation of copious accelerated negative ions from the nano-cluster plasma

Using Stochastic Differential Equation for Verification of Noise in Analog/RF Circuits

Today’s analog/RF design and verification face significant challenges due to circuit complexity, process variations and short market windows. In particular, the influence of technology parameters on circuits, and the issues related to noise modeling and verification still remain a priority for many applications. Noise could be due to unwanted interaction between the circuit elements or it could be inherited from the circuit elements. In addition, manufacturing disparity influence the characteristic behavior of the manufactured circuits. In this paper, we propose a methodology for modeling and verification of analog/RF designs in the presence of noise and process variations. Our approach is based on modeling the designs using stochastic differential equations (SDE) that will allow us to incorporate the statistical nature of noise. We also integrate the device variation due to 0.18μ m fabrication process in an SDE based simulation framework for monitoring properties of interest in order to quickly detect errors. Our approach is illustrated on nonlinear Tunnel-Diode and a Colpitts oscillator circuits

Statistical Run-Time Verification of Analog Circuits in Presence of Noise and Process Variation

Noise and process variation present a practical limit on the performance of analog circuits. This paper proposes a methodology for modeling and verification of analog designs in the presence of shot noise, thermal noise, and process variations. The idea is to use stochastic differential equations to model noise in additive and multiplicative form and then combine process variation due to 0.18 μm technology in a statistical run-time verification environment. The efficiency of MonteCarlo and Bootstrap statistical techniques are compared for a Colpitts oscillator and a phase locked loop-based frequency synthesizer circuit

The Involvement of Complement Factor B and Complement Component C2 in an Indian Cohort with Age-Related Macular Degeneration

PURPOSE. Genes involved in the complement cascade such as complement factor B (CFB) and complement component C2 have been implicated in age-related macular degeneration (AMD) worldwide. In continuation of the analysis of CFH and LOC387715/HTRA1, this study was conducted to gain understanding of the role of CFB and C2 in an Indian AMD cohort. METHODS. Single nucleotide polymorphisms in CFB and C2 were screened in a cohort of clinically well-characterized patients with AMD (n ϭ 177) and unaffected normal control subjects (n ϭ 175). Screening was accomplished by a combination of customized genotyping followed by validation through resequencing. In addition, genotyping of two CFB variants (rs12614 and rs641153) that were in close proximity had to be resolved by resequencing. Estimates of allele and genotype frequencies, odds ratios, Hardy-Weinberg equilibrium, linkage disequilibrium (LD), and haplotype frequencies were also performed. RESULTS. Three SNPs in C2 (rs547154 [IVS10] ; P ϭ 5.4 ϫ 10 Ϫ11 ) and CFB (rs641153 [R32Q], P ϭ 2.2 ϫ 10 Ϫ7 and rs2072633 [IVS17]; P ϭ 2.0 ϫ 10 Ϫ4 ) were strongly associated with reduced risk of AMD. The rs547154 and rs641153 were in strong LD (DЈ ϭ 0.90, 95% CI ϭ 0.81-0.96) and a protective haplotype T-A was observed (OR ϭ 0.10, 95% CI ϭ 0.05-0.20). LD was moderate (DЈ ϭ 0.77, 95% CI ϭ 0.67-0.85) between the rs547154 and the rs2072633 SNPs, and the haplotype T-T generated with these SNPs was relatively less protective (OR ϭ 0.28, 95% CI ϭ 0.18 -0.44). CONCLUSIONS. The results of the present study provide an independent validation of the association of rs547154 (C2) and rs641153 (CFB) SNPs with reduced risk of AMD in an Indian cohort. (Invest Ophthalmol Vis Sci

Kleinia subrahmanianii (Asteraceae: Senecioneae), a new species from southern Western Ghats, Kerala, India

Kleinia subrahmanianii, a new species of Asteraceae from southern Western Ghats is described and illustrated. Kleinia subrahmanianii is allied to Kleinia grandiflora but differs in having green, terete branchlets, elliptic–oblong to linear–lanceolate non-glaucous leaves, 30–95 cm long dark–purplish scape, 7–22 drooping capitula per scape, 16–20 mm long dark–purple phyllaries, 1.3–1.7 cm long corolla tube, 2.3–3 mm long corolla lobes, 2.5–3 mm long anthers and short pappus

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias