2,500 research outputs found

    A trade-level DEA model to evaluate relative performance of investment fund managers

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    We develop a trade-level measure to evaluate fund managers’ efficiency in their buying and selling activities relative to the trades of other fund managers. We customize an additive Data Envelopment Analysis (DEA) model to focus on risk-adjusted returns during different time periods as trade-level outcomes. The model does not consider any input-output process. Instead, it considers tradeoffs between multiple outcomes. We find that fund managers do not have symmetric ability in buying and selling. Some managers do well in buy transactions but not in sell transactions while others perform well in selling but not in buying. We also explore the determinants of fund managers’ trading performance. Compared to trade characteristics, portfolio characteristics have a greater influence in explaining fund managers’ relative trading efficiency

    Outcome of pregnancy in gestational diabetes as compared to overt diabetes

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    Background: Diabetes mellitus is a chronic metabolic disorder characterised by polyuria, polyphagia, polydipsia and glycosuria. Diabetes in pregnancy can be defined as pregestational (pre-existing) diabetes or gestational diabetes have type 1 (T1DM) or type 2 (T2DM) diabetes mellitus. Present study was carried to compare the maternal and perinatal outcome of overt diabetes mellitus as compared to gestational diabetes mellitus (PGDM) with that of gestational diabetes (GDM).Methods: An observational study was conducted at obstetrics and gynaecology department of a tertiary care center from July 2010 to October 2012 among 23 diabetic women. Seven of them were cases of overt diabetes while 16 were diagnosed during pregnancy. Maternal and fetal outcome were studied. All patients were followed from time of admission to discharge from hospital.Results: mean age of the participants were 26.71±4.89 in overt diabetes as compared to 27.56±4.41 among gestational diabetes. Illiteracy, low socio-economic status, rural residence, family history of diabetes was also high in overt diabetes mellitus as compared to GDM but none of them was statistically significant (P < 0.05). Intrauterine fetal death was more among GDM (37.5%) as compared to overt diabetes (28.57%). Prematurity and LBW were also high in overt diabetes as compared to GDM but none of them were statistically significant. Oligohydramnios, polyhydramnios and premature rupture of membrane were higher in gestational diabetes mellitus as compared to overt diabetes among women. Rate of LSCS were higher in gestational diabetes.Conclusions: Diabetes whether over or gestational is responsible for the poor outcome of the pregnancy so tight control is needed.

    Regional R&D efficiency in Korea from static and dynamic perspectives

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    Regional R&D efficiency in Korea from static and dynamic perspectives, Regional Studies. Research and development (R&D) efficiency has gained great attention in regional innovation research. This study examines the R&D efficiency patterns of 15 Korean regions for 2005–09. It employs data envelopment analysis to identify the regions' R&D performances relative to the best practices from the static perspective, and the Malmquist productivity index to evaluate their changes in performance within a given timeframe, providing a dynamic perspective. The results classify the Korean regions into deteriorating, lagging and improving groups, and indicate that most regions suffer from declining R&D productivity over time because of their inability to catch up with the best practices

    A VALUE PLATFORM ANALYSIS PERSPECTIVE ON CUSTOMER ACCESS INFORMATION TECHNOLOGY

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    Customer access information technologies (CAITs) provide a link between a firm and its customers. Firms invest in CAITs to reduce costs, increase revenues and market share, lock in existing customers and capture new ones. These benefits, however, are notoriously difficult to measure. This paper proposes an evaluative method for CAlT deployment called value platform analysis, that is based on a conceptual model drawn from the theory of retail outlet deployment in marketing science. The model focuses on the impact of CAIT features and environmental features on transactions generated by the CAIT. Specific econometric models are developed for deployment. Hypotheses regarding the likely impact of automated teller machine (ATM) location design choices and environmental features on ATM transactions are evaluated. The results indicate that there are a number of key features influencing ATM performance. Two distinct ATM deployment scenarios emerge: one for servicing a bank's own customers, and another for providing transaction services for customers for a fee.Information Systems Working Papers Serie

    The competitiveness of nations and implications for human development

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    This is the post-print version of the final paper published in Socio-Economic Planning Sciences. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.Human development should be the ultimate objective of human activity, its aim being healthier, longer, and fuller lives. Thus, if the competitiveness of a nation is properly managed, enhanced human welfare should be the key expected consequence. The research described here explores the relationship between the competitiveness of a nation and its implications for human development. For this purpose, 45 countries were evaluated initially using data envelopment analysis. In this stage, global competitiveness indicators were taken as input variables with human development index indicators as output variables. Subsequently, an artificial neural network analysis was conducted to identify those factors having the greatest impact on efficiency scores

    Investigation into Cryogenic Tank Insulation Systems for the Mars Surface Environment

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    In order to use oxygen that is produced on the surface of Mars from In-Situ production processes in a chemical propulsion system, the oxygen must first be converted from vapor phase to liquid phase and then stored within the propellant tanks of the propulsion system. The oxygen must then be stored in the liquid phase for several years between when the liquefaction operations are initiated and when the ascent stage lifts off the Martian surface. Since the Space Exploration Initiative, NASA has been investing small sums of money into soft vacuum systems for Mars Applications. A study was done into these various insulation systems for soft vacuum insulation, to determine what types of systems might be best to further pursue. Five different architectures or cycles were considered: Aerogel-based multilayer Insulation (MLAI), Space Evacuated Mars Vacuum Jacket (SEMOV) (also known as lightweight vacuum jacket), Load Responsive-Multilayer Insulation, Spray on Foam with MLI, and MLAI in SEMOV. Models of each architecture were developed to give insight into the performance and losses of each of the options. The results were then compared across six categories: Insulation System Mass, Active System Power (both input and heat rejection), Insulation System Cost, Manufacturability, Reliability, and Operational Flexibility. The result was that a trade between reliability and mass was clearly identified. Systems with high mass, also had high perceived reliability; whereas, systems with lower mass and power had a much lower perceived reliability. In the end, the numerical trades of these systems showed nominally identical rankings. As a result it is recommended that NASA focus its Martian insulation development activities on demonstrating and improving the reliability of the lightweight identified systems

    OTIMIZAÇÃO DE PORTFÓLIOS: ANÁLISE DE EFICIÊNCIA

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    This article aims to analyze the behavior of a portfolio of assets selected by Data Envelopment Analysis (DEA), optimized by the Sharpe approach, and compare it to portfolios of assets obtained only by DEA or the Sharpe approach. To do that, we used the DEA model to assess the efficiency of shares of the São Paulo Stock Exchange (Bovespa), employing return, variance and other indicators such as input and output variables. Also, we used the Sharpe approach to optimize the portfolio composition. In the comparison of portfolios, we noted that the resulting combination of both models performed better than the portfolios optimized by only one of the models

    Evaluando el progreso de la eficiencia con tecnología en una cadena de hoteles española

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    This paper analyzes the changes in the total factor productivity index of a Spanish hotel chain in the period from 2007 to 2010 with the purpose of identifying efficiency patterns for the chain in a period of financial crisis. The data envelopment analysis (DEA) Malmquist productivity index was used to estimate productivity change in 38 hotels of the AC chain. Results reveal AC hotels’ efficiency trends and, therefore, their competitiveness in the recession period; they also show the changes experienced in these hotels’ total productivity and its components: technological and efficiency changes. Positive efficiency changes were due to positive technical efficiency rather than technological efficiency. The recession period certainly influenced the performance of AC Hotels, which focused on organizational changes rather than investing in technology.Este artigo analisa as mudanças no fator total de produtividade de uma cadeia de hotéis na Espanha, no período de 2007-2010, com o propósito de identificar os padrões da cadeia em um período de crise financeira. O índice data envelopment analysis (DEA) Malmquist de produtividade foi usado para estimar a mudança da produtividade nos 38 hotéis da AC Cadeia de Hotéis. Os resultados revelaram as tendências de eficiência e competitividade da AC Hotéis em um período de recessão, bem como as mudanças vivenciadas na produtividade total e, consequentemente, em seus componentes de eficiência e tecnológicos. O período de recessão influenciou, sem dúvida, o comportamento da AC Hotéis, que buscou mais mudanças organizacionais do que tecnológicas.Este artículo analiza los cambios del índice de productividad del factor total de una cadena de hoteles españoles en el periodo de 2007 hasta 2010, con el propósito de identificar patrones de eficiencia para la cadena en un periodo de crisis financiera. El índice de productividad data envelopment analysis (DEA) Malmquist fue utilizado para estimar el cambio de productividad en 38 hoteles de la cadena AC. Los resultados revelan las tendencias de la eficiencia de los hoteles AC y, por lo tanto, su competitividad en el periodo de recisión; ellos también demuestran los cambios experimentados en la productividad total de eses hoteles y sus componentes: cambios de eficiencia y tecnológicos. Cambios de eficiencia positivos se debieron más bien a eficiencias técnicas positivas que a eficiencias tecnológicas. El periodo de recesión ciertamente ha influenciado los Hoteles AC, que enfocaron más en los cambios organizacionales que en invirtiendo en tecnología
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