244 research outputs found
A Survey of Stellar Families: Multiplicity of Solar-type Stars
No full textI present the results of a comprehensive assessment of companions to 454 solar-type stars within 25 pc. New observational aspects of this work include surveys for (1) very close companions with long-baseline interferometry at the Center for High Angular Resolution Astronomy (CHARA) Array, (2) close companions with speckle interferometry, and (3) wide proper motion companions identified by blinking multi-epoch archival images. I have also obtained and included unpublished results from extensive radial velocity monitoring programs. The many sources utilized enable a thorough evaluation of stellar and brown dwarf companions. The results presented here include eight new companion discoveries, four of which are wide common proper motion pairs discovered by blinking archival images, and four more are from the spectroscopic data. The overall observed fractions of single, double, triple, and higher order systems are 57%±3%, 33%±2%, 8%±1%, and 3%±1%, respectively, counting all stellar and brown dwarf companions. The incompleteness analysis indicates that only a few undiscovered companions remain in this well-studied sample, showing that a majority of the solar-type stars are single. Bluer, more massive stars are more likely to have companions than redder, less massive ones. I confirm earlier expectations that more active stars are more likely to have companions. A preliminary, but important indication is that brown dwarfs, like planets, prefer stars with higher metallicity, tentatively suggesting that brown dwarfs may form like planets when they are companions to stars. The period distribution is unimodal and roughly Gaussian with peak and median values of about 300 years. The period-eccentricity relation shows a roughly flat distribution beyond the circularization limit of about 12 days. The mass-ratio distribution shows a clear discontinuity near a value of one, indicating a preference for twins, which are not confined to short orbital periods, suggesting that stars form by multiple formation mechanisms. The ratio of planet hosts among single, binary, and multiple systems are statistically indistinguishable, suggesting that planets are as likely to form around single stars as they are around components of binary or multiple systems at sufficiently wide separations
Polarimetric radar modeling of mixtures of precipitation particles
No full textWith the recent advances of dual-polarized radar techniques in meteorology it is now possible to deduce precipitation microphysical characteristics in far more detail than possible with reflectivity measurements alone. Radar parameters such as differential reflectivity and differential phase between horizontal and vertical polarizations have been studied in detail as well as linear depolarization ratio, copolar correlation coefficient, and backscatter differential phase. While these parameters can be linked to certain microphysical properties of specific classes of precipitation such as raindrops or hail, very little study has been directed at the practically important cases of mixtures of different types of precipitation particles such as rain, hail, graupel, ice crystals, and snow. Each type can have different size, shape, orientation, and dielectric constant distributions. The treatment here is rigorous and is based on the Mueller matrix formulation. Radar parameters are derived from the averaged Mueller matrix computations. Careful consideration is given to the orientation and size distributions of the different particle types. After calculating single particle scattering characteristics, some simple two-component mixtures such as rain/hail and ice crystals/snow are considered. Finally, a 2D numerical cloud model is used to simulate the rain, hail/graupel, and snow fields of an evolving convective storm from which the radar parameters are derived for the initial, peak, and dissipating stages of the storm. Model computations are performed at C and S-band frequencies.This work was supported by the FAA under Contract DTFA01-90-Z-02005 and the National Science Foundation under Contract ATM-9214864. The work of R. Raghavan was also supported by NASA through USRA under Contract NAS8-37140. The National Center for Atmospheric Research is sponsored by the National Science Foundation
Project Management Learnings from Ramayana
No full textRamayana is the first Indian Epic also known as Adhi Kavya comprising 24000 shlokas, grouped in 500 sargaswhich are divided over 7 kandas. The first author of Ramayana, written in Sanskrit, is Maharishi Valmiki. These authors have discovered multiple dimensions and implications of Ramayana in diverse fields like Management, Philosophy, Spirituality, Literature, Indian Mythology, etc. There are many teachings from this epic that can be applied in today's management-life in areas such as Project Management, Strategic Management, Leadership, Human Resource Management, and the like. In Ramayana, after the evil-spirited Ravana abducted Goddess Sita, Lord Rama who is in search of Goddess Sita, along with his brother, Lakshmana finds Lord Hanuman, a noble monkey, who played a predominant role in search of Goddess Sita and destruction of Ravana, the king of Lanka. After finding the whereabouts of Goddess Sita, they prepared for a war with Ravana to bring her back to Ayodhya. They also prepared for the Coronation of Lord Rama; so that" the Prince in exile becomes the King of Ayodhya". Objective: The application of Agile Project Management at the time of searching Goddess Sita in Ramayana. Methodology: Agile Project Management methodology is used in this research study, which has four main stages: Project Initiation, Project Planning, Project Execution, and Project Closure The research study tries to understand in detail how Ramayana's knowledge-repository is integrated into the modern-day Agile Project Management Methodology. Results: Valmiki Ramayana is extremely wealthy in portraying multiple examples of Project Management methodologies, synthesizing of Agile Project Methodologies from Ramayana, and application of Project Management to modern-day Projects. Implications: The results from this article can be applied to today's management life like – Project Management, Strategic Management, Leadership, and Human Resource Management
SENSORY AUTONOMOUS COUPLING
No full textThe autonomous nervous system plays a major role in controlling the bodily functions. The autonomous system is known to be modulated by strong changes in the environment with the central nervous system involved in it. But does the autonomous system immediately respond with respect to mild and neutral sensory stimuli still remains unanswered. In this study we look at immediate responses of the autonomous network to these sensory stimuli. We exploited the large scale control over the blood flow by the autonomous system to understand the immediate effects on autonomous network with sensory stimuli. We then trained a machine to predict the sensory stimuli based on contrast in patterns of blood flow. The machine was able to predict the different sensory stimuli with high accuracy suggesting that there exist an immediate sensory-autonomous coupling. This results opens a path to a lot of questions as to how this coupling is achieved
Patentopia: A multi-stage patent extraction platform with disambiguation for certain semantic challenges
No full textBibliographic name disambiguation is an major semantic challenge, but critical to social sciences studies of important intellectual assets. Here we contribute to innovation research in several ways. We show a significant synonym problem in author names and discuss how a pre-processing heuristic step standardizing name variants helps, but homonyms generated with Chinese names are particularly difficult to resolve and manifest in an associated location list. Here we identify a new phenomenon of "onomastic profusion," the frequent use of certain words in firm names for semantic reasons that can confound disambiguation clustering algorithms. We illustrate these concerns with Patentopia, our customized platform accessing the PatentsView portal for the United States Patent and Trademark Office database and available for free academic use. This multi-stage system uses heuristics in concert with the PatentsView clustering process and reports meta-data to further assist analysis. As highly relevant use cases, we illustrate system performance with data derived from two important public innovation programs, I-Corps and Small Business Innovation Research (SBIR), and we close with implications for bibliometric analysis of current patent data.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Delft Centre for Entrepreneurshi
Nonzero-sum Stochastic Games
No full textThis paper treats of stochastic games. We focus on nonzero-sum games and provide a detailed survey of selected recent results. In Section 1, we consider stochastic Markov games. A correlation of strategies of the players, involving ``public signals'', is described, and a correlated equilibrium theorem proved recently by Nowak and Raghavan for discounted stochastic games with general state space is presented. We also report an extension of this result to a class of undiscounted stochastic games, satisfying some uniform ergodicity condition. Stopping games are related to stochastic Markov games. In Section 2, we describe a version of Dynkin's game related to observation of a Markov process with random assignment mechanism of states to the players. Some recent contributions of the second author in this area are reported. The paper also contains a brief overview of the theory of nonzero-sum stochastic games and stopping games which is very far from being complete.average payoff stochastic games, correlated stationary equilibria, nonzero-sum games, stopping time, stopping games
A comparative study on BEM solvers for Wave Energy Converters
No full textWave Energy Converters (WECs) are expected to significantly contribute to the energy transition; however, this depends on their interactions with the resource. Calculating the power generated by WECs depends heavily on the accurate modelling of wave-structure interactions. The Boundary Element Method (BEM) based on the potential flow theory has yielded accurate results at low computational costs when compared to complex Computational Fluid Dynamics (CFD) methods. Hydrodynamic Analysis of Marine Structures (HAMS), a recently developed open-source BEM frequency domain solver, originally was created for large marine structures. To date it has only been applied to single WECs with spherical/cylindrical geometries. HAMS offers unique advantages through its efficient removal of irregular frequencies and lower computational costs. This paper aims to compare hydrodynamic coefficients, exciting forces, Response Amplitude Operators (RAOs) and computational costs between HAMS,WAMIT, and NEMOH for a cylindrical point absorber and an oscillating surge WEC, extending the currently limited WECs application in HAMS.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Offshore Engineerin
Detection of Cognitive Features from Web Resources in Support of Cultural Modeling and Analysis
No full textThe World Wide Web serves as a valuable source of culture-relevant information, which can be used to support cultural modeling and analysis activities. Part of the challenge in exploiting the Web as a source of culture-relevant information relates to the need to detect and extract information about beliefs, attitudes, and values from a variety of different resources. The Web thus features a rich variety of information resources, and these are seldom categorized with respect to the dimensions in which cultural analysts are interested. Exploiting the Web as a source of culture-relevant information therefore requires techniques and approaches that enable cultural analysts to extract relevant information and organize extracted content in various ways. In this paper, we outline an approach to assist cultural analysts in the extraction and organization of relevant information. We show techniques that can be used to extract information about the attitudes, beliefs, and values of individuals, and how this data can, in turn, be used to support cultural modeling and analysis
Compensation through Writ Petitions: An Analysis of Case Law
No full textIn this article, the author has tried to find out the trend of the Supreme Court in the area of Compensatory Jurisprudence. The author has noted all the decisions in a manner which will help subsequent researchers to get their fundamental materials
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