Modélisation dynamique inverse de tissus - Apprentissage profond à l'aide de simulations basées sur la physique

Inverse problems arise in various physical domains and solving them from real-world visual observations poses a significant challenge due to the high dimensional nature of the data. Furthermore gathering enough observations that a data driven model can accurately capture the complete distribution of a physical phenomenon is often intractable. In this work we use deep learning to solve inverse problems by applying two basic principles. Deep learning models can be trained using synthetic data generated from physics based simulations. And the employed simulator itself needs to be verified for physical accuracy thus allowing the model to learn the exact physical phenomenon that is desired.To validate the simulator, we introduce rich and compact physical protocols, originally proposed in soft matter physics literature to measure physical parameters. These protocols can be easily replicated in a simulator to test the physical correctness of the model, and the validity of the simulator.We solve the inverse measurement problem of estimating contact friction in soft-bodies which otherwise requires a specialized physics bench and entails tedious acquisition protocols. This makes the prospect of a purely non-invasive, video-based measurement technique particularly attractive. Previous works have shown that such a video-based estimation is feasible for material parameters using deep learning, but this has never been applied to the friction estimation problem which results in even more subtle visual variations. Since acquiring a large dataset for this problem is impractical, we generate it using a frictional contact simulator. As the simulator has been calibrated and verified using controlled experiments, the results are not only visually plausible, but physically-correct enough to match observations made at the macroscopic scale. We propose to our knowledge the first non-invasive measurement network and adjoining synthetic training dataset for estimating cloth friction at contact, for both cloth-hard body and cloth-cloth contacts. We also acquire an extensive dataset of real world experiments for testing. Both the training and test datasets have been made freely available to the community.We also utilize the same protocol for solving the inverse measurement problem of estimating the deformed curvature of a suspended Kirchhoff rod. In order to do such estimation on physical rods, we utilize a deep learning model to visually predict a curvature field from a suspended rod. As creating a dataset from physical rods (even if synthetically constructed), that faithfully covers a representative manifold of deformed curvatures is intractable, we rely on generating such a dataset from a verified simulator. Our work shows a promising way forward for utilizing deep learning models as part of an inversion measurement pipeline.Des problèmes inverses surviennent dans divers domaines physiques et les résoudre à partir d'observations visuelles du monde réel pose un défi important en raison de la nature hautement dimensionnelle des données. De plus, rassembler suffisamment d'observations pour qu'un modèle basé sur les données puisse capturer avec précision la distribution complète d'un phénomène physique est souvent insoluble. Dans ce travail, nous utilisons l'apprentissage profond pour résoudre des problèmes inverses en appliquant deux principes de base. Les modèles d'apprentissage profond peuvent être entraînés à l'aide de données synthétiques générées à partir de simulations basées sur la physique. Et la précision physique du simulateur employé, lui-même, doit être vérifiée, permettant ainsi au modèle d'apprendre le phénomène physique exact souhaité.Afin de valider le simulateur, nous introduisons des protocoles physiques riches et compacts, proposés à l'origine dans la littérature de physique de la matière molle pour mesurer des paramètres physiques. Ces protocoles peuvent être facilement répliqués dans un simulateur pour tester l'exactitude physique du modèle et la validité du simulateur.Nous résolvons le problème de mesure inverse de l'estimation du frottement de contact dans les corps mous qui nécessite sinon un banc de physique spécialisé et un protocole d'acquisition fastidieux. Cela rend la perspective d'une technique de mesure purement non invasive basée sur la vidéo particulièrement attrayante. Des travaux antérieurs ont montré qu'une telle estimation basée sur la vidéo est réalisable pour les paramètres de matériaux en utilisant l'apprentissage profond, mais cela n'a jamais été appliqué au problème d'estimation de la friction qui entraîne des variations visuelles encore plus subtiles. Étant donné qu'il n'est pas pratique d'acquérir un grand ensemble de données pour ce problème, nous le générons à l'aide d'un simulateur de contact frictionnel. Comme le simulateur a été calibré et vérifié à l'aide d'expériences contrôlées, les résultats sont non seulement visuellement plausibles, mais suffisamment corrects physiquement pour correspondre aux observations faites à l'échelle macroscopique. Nous proposons à notre connaissance le premier réseau de mesure non invasif et un jeu de données d'entraînement synthétique adjacent pour estimer le frottement du tissu au contact, à la fois pour les contacts tissu-corps dur et tissu-tissu. Nous acquérons également un vaste ensemble de données d'expériences du monde réel pour les tests. Les ensembles de données de formation et de test ont été mis gratuitement à la disposition de la communauté.Nous utilisons également le même protocole pour résoudre le problème de mesure inverse de l'estimation de la courbure déformée d'une tige de Kirchhoff suspendue. Afin de faire une telle estimation sur des tiges physiques, nous utilisons un modèle d'apprentissage profond pour prédire visuellement un champ de courbure à partir d'une tige suspendue. Comme la création d'un ensemble de données à partir de tiges physiques (même si elles sont synthétiquement construites), qui couvre fidèlement une variété représentative de courbures déformées est insoluble, nous comptons sur la génération d'un tel ensemble de données à partir d'un simulateur vérifié. Notre travail montre une voie prometteuse pour l'utilisation de modèles d'apprentissage profond dans le cadre d'un pipeline de mesure d'inversion

Is Women’s Empowerment a Thucydides’ Trap for Patriarchy in Pakistan? The Aurat (Woman) March-2020 and Bina Shah’s Before She Sleeps

The Aurat (literal meaning, “woman” in Hindi) March, first organized in Pakistan on International Women’s Day in 2018, fanned the fire of feminist struggle in Pakistan. Since its inception, Pakistan’s patriarchy has tried to supress rising feminist voices. Last year (2020), the effort to supress these voices reached an exceptional level. Feminists faced a storm of opposition in the form of counter-marches and counter-narratives which were motivated mainly by the patriarchal agency of the country. This situation provides the basis for a critical examination of the deeply rooted patriarchal mind set, with reference to the prevailing gender politics of Pakistan. However, this paper studies this recent development of Pakistani feminism by contextualizing it within Greenblatt’s constructs of power, subversion, and containment, with particular reference to Bina Shah’s novel Before She Sleeps. By contextualizing the selected novel within the recent feminist development, this paper unmasks the way patriarchy responds to it and tries to contain it. This paper relies on the New Historicist approach to examine the feminist voices in the selected novel. For this purpose, the novel has been read in the backdrop of the feminist narrative of The Aurat March as manifested in different slogans of the march. By doing so, the paper highlights the containment strategies that were employed by the patriarchal agency in Pakistan as well as its manifestation in the contemporary Pakistani Anglophone literature. However, the study finds that the patriarchal agency in Pakistan employs various containment strategies—in the form of narratives of honour and domesticity—to contain the subversion it faces in the form of The Aurat March, and Shah’s novel textualizes the situation with utmost clarity. And instead of surrendering to the normative patriarchal structure, it offers the possibility of negotiation and change

Various doping concentration effect on silicon on insulator (SOI) phase modulator

This paper reports the effect of doping concentration to the electrical characteristic performance of the phase modulator in the carrier injection mode at wavelength 1.55μm. The phase modulator device has been integrated in the silicon-on-insulator (SOI) rib waveguide with the p-i-n diode structure. The electrical device performance is predicted using the 2-D semiconductor package SILVACO (CAD) software under DC operation. The least doping concentration of p+ and n+ region produces the least change of refractive index of the modulator. Meanwhile, results show that by increasing the doping concentrations, the value of Iπ decreases. This means that the phase modulator performance is better with increased doping concentrations

Titanium Cage Fixation in Thoracic and Thoraco-lumbar Anterior Inter-body Fusion

nner by inter body fusion. Study Design:  Prospective Study. Material and Method:  The study was conducted at the department of neurosurgery Lahore general hospital Lahore. Results:  Thirty cases were included during period two years. All cases operated for decompression, fusion and instrumentation, cages of titanium mesh were used. Neurological status of the patients assessed before and after operation. Twenty eight (93.3%) cases improved neurologically. Two (6.7%) did not improved. There were three infected cases which were treated and improved in the long run. Conclusion:  By using anterior interbody fusion (AIF) with cage we can mobilize the patient early. Improvement of the neurological status is excellent. Per operative infection rate is very low. Deformity can be corrected with more accuracy. Key Words:  Anterior cervical corpectomy, anterior dorsal inter body fusion, anterior, posterior and lateral, computed tommography, magnetic resonance imaging

Various Doping Concentration Effect on Silicon-on-Insulator (SOI) Phase Modulator

This paper reports the effect of doping concentration to the electrical characteristic performance of the phase modulator in the carrier injection mode at wavelength 1.55μm. The phase modulator device has been integrated in the silicon-on-insulator (SOI) rib waveguide with the p-i-n diode structure. The electrical device performance is predicted using the 2-D semiconductor package SILVACO (CAD) software under DC operation. The least doping concentration of p+ and n+ region produces the least change of refractive index of the modulator. Meanwhile, results show that by increasing the doping concentrations, the value of I decreases. This means that the phase modulator performance is better with increased doping concentrations

Operation mode of phase modulation based on carrier dispersion effect in p-i-n diode of silicon rib waveguide

This paper highlights the study of the carrier injection mode and the carrier depletion mode of the phase modulator. The phase modulator device has been integrated in the silicon rib waveguide by using the p-i-n diode structure. The electrical device performance is predicted by using the 2-D semiconductor package SILVACO (CAD) software under DC operation. Summarily, the phase modulator device has less sensitivity to the effective refractive index changes when operating in reverse biased or depletion mode compared to the forward biased or injection mode

Phase modulator based on Silicon-on-Insulator (SOI) rib waveguide

This paper presents the study of electrical characteristic of phase modulator in the carrier injection mode. The phase modulator device has been integrated in the silicon-oninsulator (SOI) rib waveguide by using the p-i-n diode structure. The electrical device performance is predicted by using the 2-D semiconductor package SILVACO (CAD) software under DC operation. In summary, the phase modulator device required 0.035mA drive current to get phase shift at wavelength 1.55μm meanwhile 0.066mA drive current is required for the 1.3μm wavelength

‘Texts’ Battling COVID-19: A New Historicist Reading of My Hero Is You Published by UNICEF

New Historicist approach assumes power to be using texts and co-texts as tools to build as well as retain a certain set of ideology. Since the pandemic has re-defined the personal space of individuals as a precaution to avoid the containment and the spread of COVID-19, the world has come across an ideology of restraint, to live and survive. In other words, social distancing is about to become a new normative structure throughout the world. The study strives to view, how texts and co-texts are being used by the world powers to fashion selves those comply with the new normative, i-e., social distancing and personal care. It also shows the representation of COVID-19 in the literary discourse produced during this pandemic and re-validates Stephen Greenblatt’s constructs of power, subversion and containment in this particular context. The essay, having analysed the child fiction My Hero is You published by UNICEF, finds that this pandemic has changed the dynamics of world politics by bringing all the world governments on one page to fight with COVID-19 and that they are relying heavily on literary as well as non-literary discourses to introduce and implement the new normative of social distancing and personal care. The study also suggests that this pandemic has also accorded the draconian image of power a new form, as this time power is trying to inculcate the ideology that favours humanity; and with the help of these ‘texts’, power wants to construct selves those comply with this new normative.   &nbsp

2x2 Optical Switch Based on Silicon-On-Insulator Microring Resonator

In near future, silicon-on-insulator (SOI) microring resonator are expected to be basic components for wavelength filtering and switching due to their compact size and wide free spectral range (FSR). In this paper, a 2X2 optical switch by using active microring resonator is proposed. The switch is consists of second order serially cascaded microring coupled to a pair of waveguide. The ON/OFF state of the design is control by electric signal which will vary the refractive index. The device is design to operate at 1.55μm wavelength. With a 500nm x 200nm rib dimensions, the design is proven to have single mode behaviour. Finite-Difference Time-Domain (FDTD) method simulation by RSOFT software is use to characterize the device performance. The results show that the 2X2 optical switch proposed can be an efficient device to be functioning in WDM application

Electro-Optical Modulator Performance in SOl

Since 1980's, silicon photonic devices have been extensively studied, however a submicrometre-size photonic devices have been realized only in the last few years. Silicon properties namely the transparency in the range of optical telecommunications wavelengths and high index of refraction, have enabled the fabrication of low loss submicron waveguide. Photonic devices such as splitter, coupler, and filter have been demonstrated in silicon but once the device has been fabricated, the properties of the device are predetermined. A silicon based modulator can be used to control the flow of light, where the refractive index of the silicon waveguide can be varied thus, induce a change in the transmission properties. This paper highlights the study of carrier injection effect on silicon waveguide with p-i-n diode structure integrated on Silicon-on-Insulator (SOl). The device performance is predicted using 2D Silvaco CAD software under different applied voltages at 1.55 �m