Likelihood Ratios and Generative Classifiers for Unsupervised Out-of-Domain Detection In Task Oriented Dialog

The task of identifying out-of-domain (OOD) input examples directly at test-time has seen renewed interest recently due to increased real world deployment of models. In this work, we focus on OOD detection for natural language sentence inputs to task-based dialog systems. Our findings are three-fold: First, we curate and release ROSTD (Real Out-of-Domain Sentences From Task-oriented Dialog) - a dataset of 4K OOD examples for the publicly available dataset from (Schuster et al. 2019). In contrast to existing settings which synthesize OOD examples by holding out a subset of classes, our examples were authored by annotators with apriori instructions to be out-of-domain with respect to the sentences in an existing dataset. Second, we explore likelihood ratio based approaches as an alternative to currently prevalent paradigms. Specifically, we reformulate and apply these approaches to natural language inputs. We find that they match or outperform the latter on all datasets, with larger improvements on non-artificial OOD benchmarks such as our dataset. Our ablations validate that specifically using likelihood ratios rather than plain likelihood is necessary to discriminate well between OOD and in-domain data. Third, we propose learning a generative classifier and computing a marginal likelihood (ratio) for OOD detection. This allows us to use a principled likelihood while at the same time exploiting training-time labels. We find that this approach outperforms both simple likelihood (ratio) based and other prior approaches. We are hitherto the first to investigate the use of generative classifiers for OOD detection at test-time.Comment: Accepted for AAAI-2020 Main Trac

Self-Reported Obesity Status of School Teachers Teaching In Various Schools of District Panchkula, Haryana, India

INTRODUCTION: Being overweight and obese are a major concern across the globe, as it impact one’s quality of life.AIM: To assess the self-reported Obesity status of private school teachers teaching in various schools of district Panchkula, Haryana, IndiaMATERIALS AND METHOD: A Descriptive, cross sectional study, questionnaire based study was conducted among school teachers of Panchkula District, Haryana, India using self-reported 10 item-questionnaire. The data was duly entered into Microsoft excel wherein descriptive statistics were applied and then, regression analysis to find differences if any, was applied using SPSS version 21.0 (IBM Corp, Armonk NY)RESULTS: Of a 500 questionnaires distributed, 417 were fit for data entry (response rate 83.4%) with a majority of the study subjects being females (220,52.7%), and 97.1% of the teachers taught in private schools. The overall prevalence of obesity 15.1% was reported based on self-reported BMI. A non-significant p value of .006.(Regression analysis) between males and females with respect to their self-reported BMI was observed.CONCLUSION: Efforts are required to be directed to prevent obesity among schoolteachers, who act as role-models for their students

Versatility of type-II van der Waals heterostructures: a case study with SiH-CdCl2

Unlike bilayers or a few layers thick materials, heterostructures are designer materials formed by assembling different monolayers in any desired sequence. As a result, while multilayer materials come with their intrinsic properties, heterostructures can be tailor-made to suit specific applications. Taking SiH-CdCl 2 as a representative system, we show the potential of heterostructures for several applications, like piezoelectricity, photocatalytic water splitting, and tunnel field effect transistor (TFET). Our study confirms that the characteristics of the heterostructure mainly depend on the potential difference between the constituent monolayers. From the vast database of available layered materials, many such combinations with a suitable potential difference are expected to have similar properties. Our work points to a vast pool of assembled materials with multifunctionality, an excellent asset for next-generation device applications

Peri-urbanism in globalizing India: a study of pollution, health and community awareness

This paper examines the intersection between environmental pollution and people's acknowledgements of, and responses to, health issues in Karhera, a former agricultural village situated between the rapidly expanding cities of New Delhi (India's capital) and Ghaziabad (an industrial district in Uttar Pradesh). A relational place-based view is integrated with an interpretive approach, highlighting the significance of place, people's emic experiences, and the creation of meaning through social interactions. Research included surveying 1788 households, in-depth interviews, participatory mapping exercises, and a review of media articles on environment, pollution, and health. Karhera experiences both domestic pollution, through the use of domestic waste water, or gandapani, for vegetable irrigation, and industrial pollution through factories' emissions into both the air and water. The paper shows that there is no uniform articulation of any environment/health threats associated with gandapani. Some people take preventative actions to avoid exposure while others do not acknowledge health implications. By contrast, industrial pollution is widely noted and frequently commented upon, but little collective action addresses this. The paper explores how the characteristics of Karhera, its heterogeneous population, diverse forms of environmental pollution, and broader governance processes, limit the potential for citizen action against pollution

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data