Surrogate based Optimization and Verification of Analog and Mixed Signal Circuits

Nonlinear Analog and Mixed Signal (AMS) circuits are very complex and expensive to design and verify. Deeper technology scaling has made these designs susceptible to noise and process variations which presents a growing concern due to the degradation in the circuit performances and risks of design failures. In fact, due to process parameters, AMS circuits like phase locked loops may present chaotic behavior that can be confused with noisy behavior. To design and verify circuits, current industrial designs rely heavily on simulation based verification and knowledge based optimization techniques. However, such techniques lack mathematical rigor necessary to catch up with the growing design constraints besides being computationally intractable. Given all aforementioned barriers, new techniques are needed to ensure that circuits are robust and optimized despite process variations and possible chaotic behavior. In this thesis, we develop a methodology for optimization and verification of AMS circuits advancing three frontiers in the variability-aware design flow. The first frontier is a robust circuit sizing methodology wherein a multi-level circuit optimization approach is proposed. The optimization is conducted in two phases. First, a global sizing phase powered by a regional sensitivity analysis to quickly scout the feasible design space that reduces the optimization search. Second, nominal sizing step based on space mapping of two AMS circuits models at different levels of abstraction is developed for the sake of breaking the re-design loop without performance penalties. The second frontier concerns a dynamics verification scheme of the circuit behavior (i.e., study the chaotic vs. stochastic circuit behavior). It is based on a surrogate generation approach and a statistical proof by contradiction technique using Gaussian Kernel measure in the state space domain. The last frontier focus on quantitative verification approaches to predict parametric yield for both a single and multiple circuit performance constraints. The single performance approach is based on a combination of geometrical intertwined reachability analysis and a non-parametric statistical verification scheme. On the other hand, the multiple performances approach involves process parameter reduction, state space based pattern matching, and multiple hypothesis testing procedures. The performance of the proposed methodology is demonstrated on several benchmark analog and mixed signal circuits. The optimization approach greatly improves computational efficiency while locating a comparable/better design point than other approaches. Moreover, great improvements were achieved using our verification methods with many orders of speedup compared to existing techniques

Fertility sparing surgery for stage Ic ovarian cancer: An eight case series

Introduction. One case out of 3 cases of primary ovarian cancer is diagnosed at an early stage. Almost 15% of ovarian cancers are diagnosed in women who are within the range of procreation age, raising the debate on the feasibility of fertility-sparing surgery (FSS) for those tumors. In the case the patient is admitted with stage 1A or 1B in most histologic types, it is still controversial in stage 1C. Results and Discussions. This is an eight-patient-case series. The median age is 27 years old (ranging from 18 to 42). The main clinical manifestation was pelvic pain (87.5%). Four patients (50%) presented with tumor torsion. All patients underwent FSS; five of them (62.5%) had conservative staging, two (25%) underwent salpingooophorectomy and one (12.5%) ovariectomy, type histo + stade Figo. The chemotherapeutic treatment was administered to four patients (50%) following surgery without major side effects. One patient (12.5%) presented a loco regional recurrence that occurred 14 months later. She was treated with combined chemotherapy and radical surgery. One patient out of eight (12.5%) achieved a natural pregnancy after the treatment and another one (12.5%) was submitted to an assisted reproductive procedure which did not result in a viable pregnancy. Conclusion. FSS seems to be a suitable approach for stage 1C ovarian cancer. However, more case series and meta-analyses should be conducted

Estimation of the economic impact of a bluetongue serotype 4 outbreak in Tunisia

IntroductionSince 1999, Tunisia has experienced multiple occurrences of Bluetongue (BT) outbreaks, leading to numerous reported cases of infection and mortality in flocks. The re-emergence of the disease in 2020 caused substantial economic losses in cattle, attributed to the incursion of serotype BTV-4.MethodsTo evaluate the economic impact of the recent BT episode, we conducted a retrospective study on outbreaks that occurred in Tunisia between August and November 2020, focusing on the impact at the owner’s level and its effects on both small ruminants and cattle. A total of 234 ruminant farms (sheep, cattle, and mixed) were randomly selected across Tunisian governorates and included in the study to estimate both the direct and indirect costs of these outbreaks.ResultsTotal costs were calculated as the sum of losses and expenditures resulting from the BT outbreaks. At the animal level, total losses were estimated to range between 116.280 and 207.086 TND for one infected ewe (€33.721 and 60.055). For one lactating cow, costs varied between 2,590.724 and 3,171.107 TND (€751.310 and 919.621). In cattle, exposure to BTV led to a daily unit milk yield decrease of 12.50 to 14.66 L over an average period of 5 months. Diseased sheep experienced weight loss ranging between 4 and 10 kg during the BT outbreaks. The total mean cost of the 2020 BT outbreak in Tunisian investigated farms was estimated at 1,935 million TND (million €561.15) (range: 1,489 and 2,474 million TND; 431.81 and million €717.46). The most influential costs of the total BT outbreaks were the decrease in milk yield, mortality, and veterinary treatment.DiscussionThis study gives valuable insights on the economic impact of the incursion of a new serotype of BT in a naive population in Tunisia. Considering the substantial costs incurred, it is imperative that this disease receives increased attention from stakeholders, including animal owners, veterinary services, practitioners, and decision-makers

Abondance et origine de quelques metaux (Al, Fe, Zn, Cu, Cd, Pb) dans l'aerosol marin de la Mediterranee occidentale

SIGLECNRS T 56684 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc