1,721,010 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Models For Projectile Impact Into Hybrid Multi-Layer Armor Systems With Axisymmetric Or Biaxial Layers With Gaps
Get PDFAnalytical and numerical modeling of fibrous material resistance to penetration under impact by high-velocity projectiles has been of great interest not only for personnel protection reasons but also because trial-and-error testing is costly and time-consuming. In this thesis, two PC-based models are developed for projectile impact into a multi-layer system of membrane layers with nonzero spacings between them. The projectile is a standard right circular cylinder (RCC) often used in laboratory experiments to compare material systems, and the models blend theoretical analysis and numerical simulation to characterize the interaction between the projectile and the various layers. We first consider a system of axisymmetric layers under impact by an RCC projectile. In particular, we consider such performance measures as the critical strains in layers resulting in their failure, the strains in unfailed layers, critical layer gaps, the number of layers penetrated, and the residual velocities in cases where all layers have been penetrated. The model allows variation of mechanical properties from layer to layer as well as variations in spacings between layers, in order to study their combined effects on the ballistic performance of the system. Case studies are performed on the ballistic impact response of fibrous material systems of particular interest in body armor. These are ultra-high molecular weight polyethylene (UHMWPE) fibers such as DSM's Dyneema SK76, as well as aramid fibers such as duPont's Kevlar-29. We also develop a semi-analytical model for a multi-layered biaxial, elastic membrane system impacted by an RCC projectile. The model builds on a single-layer membrane model, which has been under development by collaborators in the overall body armor work at Cornell University. Key assumptions and parameter values in the single layer model were guided by simulation results using a code based on the finite difference method (FDM) incorporating an algorithm frequently used in molecular dynamics simulations. The code was originally developed by researchers at DSM (makers of Dyneema) and has been modified by the author and several collaborators at Cornell University to suppress local strain concentrations and dynamic artifacts resulting from the descretization of the structure, and to better handle the current geometry. Numerical simulations of impact into a flexible panel are performed where the main emphasis is on a comprehensive understanding of the strain and displacement fields, as well as on the velocity fields versus time. The panel is treated as a single biaxial membrane with negligible shear stiffness compared with the tensile stiffness, and is assigned the properties of Dyneema SK76 or Kevlar 29 biaxial fabrics and flexible composites having about 15 to 20 percent matrix content. Numerical results are obtained through incremental integration of differential equations using small time steps. Compared to simulations using the modified DSM code, there are several important improvements: (1) The calculation time has been accelerated by at least a factor of 1000; (2) Results under different parameter combinations can be obtained for larger geometric sizes and much longer times; and (3) Modeling multi-layer systems is now possible, and we present results for several cases
Impact of the elderly on household health expenditure in Bihar and Kerala, India
Get PDFDans le contexte d’une population vieillissante, nous avons étudié l’impact de la présence de personnes âgées sur les dépenses catastrophiques de santé (DCS), ainsi que leur impact sur trois effets reliés (le fait d’éviter des traitements, la perte de revenu, et l’utilisation de sources de financement alternatives). Nous avons utilisé les données d’une enquête du National Sample Survey Organization (Inde) en 2004, portant sur les dépenses reliées à la santé. Nous avons choisi un état développé (Kerala) et un état en voie de développement (Bihar) pour faire une comparaison des effets de la présence de personnes âgées sur les ménages. Nous avons trouvé qu’il y avait plus de DCS au Kerala et que ceci était probablement lié à la présence accrue de personnes âgées au Kerala ce qui mène à plus de maladies chroniques. Nous avons supposé que l’utilisation de services de santé privés serait lié à une augmentation de DCS, mais l’effet a varié en fonction de l’état, du présence d’une personne âgée, et du type de service utilisé (ambulatoire ou hospitalisation). Nous avons aussi trouvé que les femmes âgées au Bihar utilisait les services de santé moins qu’elle ne devrait, que les ménages ayant plus de 4 personnes ont possiblement un effet protecteur pour les personnes âgées, et que certains castes et group religieux ont dû emprunter plus souvent que d’autres groupes pour payer les frais de santé. La présence de personnes âgées, les maladies chroniques, et l’utilisation de services de santé privées sont tous liés aux DCS, mais, d’après nos résultats, d’autres groupes retardent les conséquences économiques en empruntant ou évitant les traitements. Nous espérons que ces résultats seront utilisés pour approfondir les connaissances sur l’effet de personnes âgées sur les dépenses de santé ou qu’ils seront utilisés dans des discussions de politiques de santé.In the context of an ageing population in India, we have examined the impact of the elderly on catastrophic health expenditure (CHE) and three related access impacts (avoidance of treatment, loss of income, and alternate sources of funding). We used data from the National Sample Survey Organization (India) survey on healthcare in 2004. We chose one developed state (Kerala) and one developing state (Bihar) to compare and contrast the impact of ageing on households. Our results showed that CHE was higher in Kerala and that this was likely due to more elderly that in turn have more chronic disease. We expected the use of private treatment to lead to higher levels of CHE, and while it did for some households, the impact of private treatment on CHE, varied by state, presence of elderly, and type of health service (inpatient or outpatient). We also found that elderly females in Bihar were at a disadvantage with regards to health services utilizations, that larger household size might have a protective effect on elderly households, and that some scheduled caste and Muslim households have to borrow more often than other groups in order to fund their treatment. While the elderly, chronic disease and private treatment are linked to CHE, our results suggest that other groups may simply be delaying the consequences of paying for healthcare, by avoiding treatment or borrowing money. We hope that these results be used to explore the impact of the elderly in more detail in future research, or that it contribute to health policy discussions
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Impact of the elderly on household health expenditure in Bihar and Kerala, India
No full textDans le contexte d’une population vieillissante, nous avons étudié l’impact de la présence de personnes âgées sur les dépenses catastrophiques de santé (DCS), ainsi que leur impact sur trois effets reliés (le fait d’éviter des traitements, la perte de revenu, et l’utilisation de sources de financement alternatives). Nous avons utilisé les données d’une enquête du National Sample Survey Organization (Inde) en 2004, portant sur les dépenses reliées à la santé. Nous avons choisi un état développé (Kerala) et un état en voie de développement (Bihar) pour faire une comparaison des effets de la présence de personnes âgées sur les ménages. Nous avons trouvé qu’il y avait plus de DCS au Kerala et que ceci était probablement lié à la présence accrue de personnes âgées au Kerala ce qui mène à plus de maladies chroniques. Nous avons supposé que l’utilisation de services de santé privés serait lié à une augmentation de DCS, mais l’effet a varié en fonction de l’état, du présence d’une personne âgée, et du type de service utilisé (ambulatoire ou hospitalisation). Nous avons aussi trouvé que les femmes âgées au Bihar utilisait les services de santé moins qu’elle ne devrait, que les ménages ayant plus de 4 personnes ont possiblement un effet protecteur pour les personnes âgées, et que certains castes et group religieux ont dû emprunter plus souvent que d’autres groupes pour payer les frais de santé. La présence de personnes âgées, les maladies chroniques, et l’utilisation de services de santé privées sont tous liés aux DCS, mais, d’après nos résultats, d’autres groupes retardent les conséquences économiques en empruntant ou évitant les traitements. Nous espérons que ces résultats seront utilisés pour approfondir les connaissances sur l’effet de personnes âgées sur les dépenses de santé ou qu’ils seront utilisés dans des discussions de politiques de santé.In the context of an ageing population in India, we have examined the impact of the elderly on catastrophic health expenditure (CHE) and three related access impacts (avoidance of treatment, loss of income, and alternate sources of funding). We used data from the National Sample Survey Organization (India) survey on healthcare in 2004. We chose one developed state (Kerala) and one developing state (Bihar) to compare and contrast the impact of ageing on households. Our results showed that CHE was higher in Kerala and that this was likely due to more elderly that in turn have more chronic disease. We expected the use of private treatment to lead to higher levels of CHE, and while it did for some households, the impact of private treatment on CHE, varied by state, presence of elderly, and type of health service (inpatient or outpatient). We also found that elderly females in Bihar were at a disadvantage with regards to health services utilizations, that larger household size might have a protective effect on elderly households, and that some scheduled caste and Muslim households have to borrow more often than other groups in order to fund their treatment. While the elderly, chronic disease and private treatment are linked to CHE, our results suggest that other groups may simply be delaying the consequences of paying for healthcare, by avoiding treatment or borrowing money. We hope that these results be used to explore the impact of the elderly in more detail in future research, or that it contribute to health policy discussions
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Multiphase Transport In Deformable Phase-Changing Porous Materials
Get PDFThe primary aim of this work is mathematical modeling of transport phenomena during processing of food materials. Quantitative information from such models can be used to design food processes that deliver microbiologically and chemically safe products with optimized food quality and process efficiency. Most factors characterizing food safety and quality can, in principle, be expressed as functions of the state and the history of a product. Thus, the emphasis is on accurate prediction of the final state of a food material- temperature, moisture (and, if present, concentration of other species such as air, fat etc.), and stresses and strains for deformable food materials, and its evolution during a process. For the purpose of mathematical modeling, most solid foods can be treated as porous materials comprising of a solid polymer matrix with water (and, if present, air, fat, oil etc.) occupying its pore space. During a food process such as frying, drying or baking, energy and mass (water and other species) transport takes place altering the state of the product. Thus, mathematically, food process is just single- or multi-phase transport in rigid or deformable porous media, with or without phase transitions. As porous media transport is widely studied across application areas, some of the physics can be borrowed from other materials (mainly, soils, wood and polymers), while some physics is specific to food materials and processes. This dissertation is a compilation of a series of modeling efforts (both theory development and applications), exploring various aspects of porous media transport. The first chapter deals with modeling of nongray radiative heat exchange in an infrared oven. The purpose is to characterize the nature and intensity of infrared radiation reaching the food material in an oven. Although the focus of this study is radiation heat transport outside food (unlike other chapters, which focus on internal transport), the study can help to elucidate the complexities involved in determining energy boundary conditions which are a necessary input to most transport models within food materials. Chapters 2 to 4 deal with multiphase transport in rigid porous materials. Chapter 2 (joint work with Dr. Amit Halder) focuses on development of a comprehensive theoretical framework for materials in which, besides mass transfer between the fluids in pore space, significant mass transfer may occur between the solid matrix and the pore space. In chapter 3, the theory developed in the previous chapter is applied to model multiphase (moisture and fat) transport in meat and the simulation results are validated against double-sided contact heating of hamburger patties. Chapter 4 deals with a non-food application, hot air drying of channeled ceramic substrates. The focus is on breakdown of the local equilibrium between liquid water and water vapor (where vapor pressure is not given by moisture sorption isotherm), a phenomena also observable and significant in food materials with large pore sizes such as bread. Finally, deformation through solid momentum balance is added to the analysis in the final 2 chapters- theoretical development with example applications in chapter 5 and detailed analysis of transport in meat (single-sided contact heating of hamburger patties) in chapter 6. Modeling framework accounting for different driving forces causing deformation (moisture change and gas pressure) is developed. Stress generation due to transition of food from a soft and rubbery state to rigid and glassy state is discussed
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