35 research outputs found
Algorithms for computing mixed multiplicities, mixed volumes and sectional Milnor numbers
Get PDFWe present a package 'MixedMultiplicity' for computing mixed multiplicities
of ideals in a Noetherian ring which is either local or a standard graded
algebra over a field. This enables us to find mixed volumes of convex lattice
polytopes and sectional Milnor numbers of hypersurfaces with an isolated
singularity. The algorithms make use of the defining equations of the
multi-Rees algebra of ideals, which are obtained by generalising a result of D.
Cox. K.-N. Lin, and G. Sosa.Comment: Vivek Mukundan joined as a new co-author. The package has improved
significantly from its earlier versio
Changing Sacredscapes: A cultural approach for a sustainable Varanasi
No full textNature is unique on earth. Civilizations over time have defined various landscapes, some of which have been changed and some are in the process. Sacredscapes are one among those that have sustained over many centuries. The urbanization is in the process of transforming this sacred identity of many cities. But what is forgotten is beyond religion, there is a strong socio-ecological balance that has kept this landscape resilient. Is there a need to preserve this identity? If so why and how? This graduation project explores the opportunities on the planning of sacredscapes, focusing on Varanasi in India. Following a cultural approach, the research proposes a regional design and strategic framework, which further shows transferability to other sacredscapes.Architecture, Urbanism and Building Sciences | Complex Citie
Author Correction: Grooved electrodes for high-power-density fuel cells
Get PDFCorrection to: Nature Energy. Published online 25 May 2023. This paper was originally published under a standard Springer Nature license (© The Author(s), under exclusive licence to Springer Nature Limited). It is now available as an open-access paper under a Creative Commons Attribution 4.0 International license, © The Author(s). The error has been corrected in the online version of the article
Surface-surface intersection with validated error bounds
Get PDFThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 97-100).This thesis presents a robust method for tracing intersection curve segments between continuous rational parametric surfaces, typically rational polynomial parametric surface patches. Using a validated ordinary differential equation (ODE) system solver based on interval arithmetic, we obtain a continuous, validated upper bound for the intersection curve segment in the parametric space of each surface. Application of the validated ODE solver in the context of eliminating the pathological phenomena of straying and looping is discussed. We develop a method to achieve a continuous gap-free boundary with a definite numerically verified upper bound for the intersection curve error in parameter space. This bound in parametric space is further mapped to an upper bound for the intersection curve error in 3D model space, denoted as model space error, which assists in defining robust boundary representation models of complex three-dimensional solids. In addition, we also discuss a method for controlling this model space error so that it takes values below a predefined threshold (tolerance). Application of the above method to various examples is further demonstrated.by Harish Mukundan.S.M
Female Leaders and Pandemic Response: Analysis of Gender Stereotypes in Media
Get PDFMedia coverage of female politicians can affect how the public perceives them as leaders. The language used by the media to portray female leaders is crucial in constructing their image as politicians. This study explored how female national leaders were represented by the global media during the pandemic and how it resulted in enhancing their stereotypical image. Social constructionism was used as the theoretical framework as the study focused on the gender representations of leaders and the language used by the media, both of which are social constructs.
News articles from the top 25 English-language news websites in the years 2020 and 2021 were selected to collect the data for the research. A combination of quantitative and qualitative assessment was done as part of the content analysis. 78 news articles were analyzed in total on the basis of nine attributes mentioned in the articles: age, professional background, family background, dressing style, characteristics associated with femininity, characteristics associated with masculinity, gender, details on personal lives, and sentiments expressed by the leaders. These attributes were formulated by the author on the basis of knowledge gathered from previous academic research. The results from the quantitative analysis were further evaluated in reference to the findings of previous research to gain a comprehensive understanding of the topic.
The results of the study suggest that the gender of the leader plays a crucial role in their media portrayal. Feminine traits are often associated with female leaders rather than their competency as leaders. Moreover, irrelevant aspects such as personal details, family, and professional background are given importance while covering news related to female leaders. While, initially, the thesis was also interested to explore whether the stereotypes were challenged, the findings of this study confirms that the language used by the media to represent female national leaders during the pandemic reiterated their stereotypical image as politicians. The results also cite the importance of media representations of female leaders and how present concept of leadership needs to improvise
Optimization of Patch Antenna Array Mounted on a Cylinder for Launch Vehicle Applications
No full textAnalysis of integrated optofluidic lab-on-a-chip sensor based on refractive index and absorbance sensing
No full textThe analysis of a fully integrated optofluidic lab-on-a-chip sensor is presented in this paper. This device is comprised of collinear input and output waveguides that are separated by a microfluidic channel. When light is passed through the analyte contained in the fluidic gap, optical power loss occurs owing to absorption of light. Apart from absorption, a mode-mismatch between the input and output waveguides occurs when the light propagates through the fluidic gap. The degree of mode-mismatch and quantum of optical power loss due to absorption of light by the fluid form the basis of our analysis. This sensor can detect changes in refractive index and changes in concentration of species contained in the analyte. The sensitivity to detect minute changes depends on many parameters. The parameters that influence the sensitivity of the sensor are mode spot size, refractive index of the fluid, molar concentration of the species contained in the analyte, width of the fluidic gap, and waveguide geometry. By correlating various parameters, an optimal fluidic gap distance corresponding to a particular mode spot size that achieves the best sensitivity is determined both for refractive index and absorbance-based sensing
Design of XNBR nanocomposites for underwater acoustic sensor applications: Effect of MWNT on dynamic mechanical properties and morphology
No full textNon isocentric film-based intracavitary brachytherapy planning in cervical cancer: a retrospective dosimetric analysis with CT planning
Get PDFPurpose:
To compare intracavitary brachytherapy dose estimation for organs at risk (bladder and rectum) based on semi-orthogonal reconstruction of radiographs on non-isocentric X-ray unit and Computed Tomography (CT) – based volumetric planning in cervical cancer.
Material and methods:
Bladder and rectal points as per International Commission on Radiation Units and Measurements (ICRU) report 38, were retrospectively evaluated on 15 high dose rate intracavitary brachytherapy applications for cervical cancer cases. With the same source configuration as obtained during planning on radiographs performed on a non-isocentric X-ray unit, the mean doses to 2cc of most irradiated part of bladder and rectum were computed by CT planning and these estimates were compared with the doses at ICRU bladder and rectal points.
Results:
The mean ICRU point dose for bladder was 3.08 Gy (1.9-5.9 Gy) and mean dose to 2 cc (D2cc) bladder was 6.91 Gy (2.9-12.2 Gy). ICRU rectal dose was 3.8 Gy (2.4-4.45 Gy) and was comparable with D2cc rectum dose 4.2 Gy (2.8-5.9 Gy). Comparison of mean total dose (ICRU point vs. D2cc) for each patient was found to be significantly different for bladder (p = 0.000), but not for rectum (p = 0.08).
Conclusions:
On comparison of ICRU point based planning with volumetric planning on CT, it was found that bladder doses were underestimated by the film based method. However, the rectal doses were found to be similar to the D2cc doses. The results with non isocentric film based treatment planning were similar to the existing literature on orthogonal film based simulator planning
