24 research outputs found
Typological variation in the ergative morphology of Indo-Aryan languages
No full textWhile New Indo-Aryan languages are a common example of morphological ergativity, the range of variation in ergative marking and agreement among these languages has not been examined in detail. The goals of this article are twofold. We first present a typology of ergative marking and agreement in Indo-Aryan languages, demonstrating that a progressive loss of ergative marking has occurred to varying degrees in different systems. This process is manifested in two distinct strategies of markedness reduction: loss of overt subject marking in the nominal domain and loss of marked agreement in the verbal domain. Using the framework of Optimality Theory, we account for the typology in terms of universal subhierarchies of markedness. Extending the analysis to dialect variation in one language, Marathi, we show that the dialect typology parallels the crosslinguistic typology, but only within the range permitted by changes already present in the parent language (Old Marathi). Furthermore, the dialect typology includes additional hybrid case-agreement systems predicted by our analysis. Author(s): Ashwini Deo 1, 1, | Devyani Sharma 2,
GraSPI: Extensible software for the graph-based quantification of morphology in organic electronics
No full textWe describe GraSPI - extensible graph-based software implemented as a C/C++ package. GraSPI computes a large set of descriptors relevant to organic electronics given a segmented 2D or 3D microstructure. The package represents a microstructure as an equivalent graph and harnesses algorithms from graph theory to compute those descriptors efficiently. It also includes a suite of tools for converting data between various formats and post-processing the raw results from the graph analysis. Herein, we provide illustrative examples of GraSPI’s capabilities in extracting microstructure descriptors and demonstrate the advantages that a graph-based approach affords via computational complexity analysis.This article is published asJivani, Devyani, Jaroslaw Zola, Baskar Ganapathysubramanian, and Olga Wodo. "GraSPI: Extensible software for the graph-based quantification of morphology in organic electronics." SoftwareX 17 (2022): 100969. DOI: 10.1016/j.softx.2021.100969. Copyright 2021 The Author(s).Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0).
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Accelerated Aging in Devices and Circuits
No full textabstract: The aging mechanism in devices is prone to uncertainties due to dynamic stress conditions. In AMS circuits these can lead to momentary fluctuations in circuit voltage that may be missed by a compact model and hence cause unpredictable failure. Firstly, multiple aging effects in the devices may have underlying correlations. The generation of new traps during TDDB may significantly accelerate BTI, since these traps are close to the dielectric-Si interface in scaled technology. Secondly, the prevalent reliability analysis lacks a direct validation of the lifetime of devices and circuits. The aging mechanism of BTI causes gradual degradation of the device leading to threshold voltage shift and increasing the failure rate. In the 28nm HKMG technology, contribution of BTI to NMOS degradation has become significant at high temperature as compared to Channel Hot Carrier (CHC). This requires revising the End of Lifetime (EOL) calculation based on contribution from induvial aging effects especially in feedback loops. Conventionally, aging in devices is extrapolated from a short-term measurement, but this practice results in unreliable prediction of EOL caused by variability in initial parameters and stress conditions. To mitigate the extrapolation issues and improve predictability, this work aims at providing a new approach to test the device to EOL in a fast and controllable manner. The contributions of this thesis include: (1) based on stochastic trapping/de-trapping mechanism, new compact BTI models are developed and verified with 14nm FinFET and 28nm HKMG data. Moreover, these models are implemented into circuit simulation, illustrating a significant increase in failure rate due to accelerated BTI, (2) developing a model to predict accelerated aging under special conditions like feedback loops and stacked inverters, (3) introducing a feedback loop based test methodology called Adaptive Accelerated Aging (AAA) that can generate accurate aging data till EOL, (4) presenting simulation and experimental data for the models and providing test setup for multiple stress conditions, including those for achieving EOL in 1 hour device as well as ring oscillator (RO) circuit for validation of the proposed methodology, and (5) scaling these models for finding a guard band for VLSI design circuits that can provide realistic aging impact.Dissertation/ThesisMasters Thesis Electrical Engineering 201
Control Strategies for Reconfigurable PV Modules
No full textPV systems in urban environments frequently get shaded by nearby objects, which greatly reduces their yield. A potential solution for such situations is the use of reconfigurable PV modules. They are a type of modules which can reconfigure themselves under varying illumination conditions to ensure optimum yield at all times. The individual PV cells of the module are grouped into reconfigurable units/ cell blocks which can be interconnected in various ways to form a variety of unique configurations. The modules have an inbuilt algorithm which is responsible for controlling the reconfiguration process. There are various kinds of reconfiguration algorithms found in literature, each working with varying input parameters and operating principles. One such algorithm is the short circuit current sensing (SCCS) algorithm developed by the PVMD research group at TU Delft. The algorithm is meant for series-parallelconnected reconfigurable modules and uses each cell block’s short circuit current as input. It is a synchronous reconfiguration algorithm, which means it runs at regular time intervals and not when there is actually a change in the module’s irradiance conditions. Therefore, the aim of this thesis was to develop a robust reconfiguration algorithm with a shade detection mechanism. Consequently, numerous versions of a reconfiguration algorithm with shade detection mechanism were defined and tested using a simulation framework for modelling reconfigurable PV modules. It was observed that the reconfiguration algorithm that performed the best in terms of yield, reconfiguration count and accuracy was the one referred to as the ”CC4AP+IR algorithm”. The algorithm uses the module’s and a single cell block’s operating current and voltage as inputs for shade detection. It was observed that the algorithm reconfigured a fraction of the time that the SCCS algorithm reconfigured and had a DC yield comparable to the SCCS algorithm. The new algorithm was also tested using real-life data to validate its performance. This experiment indicated that if the module were to be run using the new reconfiguration algorithm instead of the SCCS algorithm, it would have run only 6% of the time that the SCCS algorithm ran, but have a comparable DC yield. The significantly lower reconfiguration count is relevant because in practice, the PV modules are connected to power converters which will not be able to tolerate the high fluctuations in output owing to frequent reconfigurations.Electrical Engineering | Sustainable Energy Technolog
Warfarin use and risk of osteoporotic fractures
No full textThesis (M.S.M.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at [email protected]. Thank you.OBJECTIVE: Prior studies examining the association of warfarin use and osteoporotic fractures have found conflicting results and have had methodological problems, such as confounding by indication and confounding by duration of warfarin use. Thus, we studied the association of warfarin use with fractures at the hip, spine and wrist, among older men and women with atrial fibrillation recruited from the general population, using rigorous statistical tools to overcome challenges faced by prior studies.
METHODS: We included men and women ≥65 years with incident atrial fibrillation, without history of fracture, followed between 2000-2010 from The Health Improvement Network (THIN). Long-term warfarin use was defined in two ways: 1) warfarin use ≥ 1year; 2) warfarin use ≥3 years. Non-use was defined as no use of warfarin over the follow-up period. Propensity scores (PS) for warfarin use were calculated using logistic regression with long-term use of warfarin as the dependent variable and age, sex, body mass index (BMI), history of multiple falls, deep venous thrombosis, pulmonary embolism, heart failure, neuropsychiatric impairment, hyperthyroidism, estrogen use, beta blockers, corticosteroids, bisphosphonates, smoking and alcoholism as independent variables. Each warfarin user was then matched by PS to a non-user by the “greedy matching” method. Incidence rates were calculated for warfarin users and non-users. The association between long-term warfarin use and risk of hip, spine and wrist fractures was evaluated using Cox-proportional hazards models.
RESULTS: Incidence rates of hip fracture were 5.21 and 6.20 per 1000 person-years among subjects with warfarin use >1 (n=20,346) and >3 (n=11,238) years, respectively. The hazard ratios of hip fracture for warfarin use >1 and >3 years were 1.08 (95% CI 0.87, 1.35) and 1.13 (95% CI: 0.84, 1.5), respectively. Similar findings were observed between warfarin use and risk of spine or wrist fracture.
CONCLUSIONS: Long-term use of warfarin among older adults with atrial fibrillation is not associated with increased risk of osteoporotic fractures and thus, does not necessitate additional surveillance or prophylaxis.2031-01-0
Craniofacial Chondromyxoid Fibromas: A Systematic Review and Analysis Based on Anatomic Locations
No full textTDDB in HfSiON/SiO<inf>2</inf> dielectric stack: Büttiker probe based NEGF modeling, prediction and experiment
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