Search results for "Value theory"
showing 10 items of 49 documents
Northern Hemisphere extratropical cyclones: A comparison of detection and tracking methods and different reanalyses
2008
Abstract The applicability of three different cyclone detection and tracking schemes is investigated with reanalysis datasets. First, cyclone climatologies and cyclone characteristics of the 40-yr ECMWF Re-Analysis (ERA-40) are compared with the NCEP–NCAR dataset using one method. ERA-40 shows systematically more cyclones, and therefore a higher cyclone center density, than the NCEP–NCAR reanalysis dataset. Geostrophically adjusted geopotential height gradients around cyclone centers, a measure of cyclone intensity, are enhanced in ERA-40 compared with the NCEP–NCAR reanalysis dataset. The variability of the number of cyclones per season is significantly correlated between the two reanalysi…
Estimation of sub-hourly DDF curves using scaling properties of hourly and sub-hourly data at partially gauged site
2005
Abstract In urban drainage systems, knowledge of short-duration rainfall events can be considered as one of the most critical elements when their hydrological behaviour wants to be investigated. The temporal resolution of rainfall data usually available for practical applications is often lower than the data requested for the design procedures or mathematical models application, greatly affecting their reliability. Moreover, when high resolution rain gauges are available in the catchment, the registration period cannot be sufficiently long for obtaining practically usable statistical analyses. The present study proposes a method for estimating the distribution of sub-hourly extreme rainfall…
Quantifying transport into the lowermost stratosphere using simultaneous in-situ measurements of SF<sub>6</sub> and CO&am…
2009
Abstract. The seasonality of transport and mixing of air into the lowermost stratosphere (LMS) is studied using distributions of mean age of air and a mass balance approach, based on in-situ observations of SF6 and CO2 during the SPURT (Spurenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region) aircraft campaigns. Combining the information of the mean age of air and the water vapour distributions we demonstrate that the tropospheric air transported into the LMS above the extratropical tropopause layer (ExTL) originates predominantly from the tropical tropopause layer (TTL). The concept of our mass balance is based on simultaneous measurements of the two pas…
Controlling false match rates in record linkage using extreme value theory
2011
AbstractCleansing data from synonyms and homonyms is a relevant task in fields where high quality of data is crucial, for example in disease registries and medical research networks. Record linkage provides methods for minimizing synonym and homonym errors thereby improving data quality. We focus our attention to the case of homonym errors (in the following denoted as ‘false matches’), in which records belonging to different entities are wrongly classified as equal. Synonym errors (‘false non-matches’) occur when a single entity maps to multiple records in the linkage result. They are not considered in this study because in our application domain they are not as crucial as false matches. Fa…
Diffuse UV erythemal radiation experimental values
2007
[1] Measurements of diffuse UV erythemal radiation (UVER) using a shadowband have been corrected using the models proposed by Drummond (1956), LeBaron et al. (1990), and Batlles et al. (1995). Two different methods were used to validate these models: intercomparison with an Optronic OL754 spectroradiometer and comparison with the values simulated by two radiative transfer codes, SMARTS and SBDART. For this comparison only clear days have been used. The corrected experimental values were analyzed in order to study the average values of the diffuse UVER fraction in relation to the clearness index kt. These varied between 62%, for kt close to 0.8, and 93% for kt of 0.2–0.3. Finally, a study of…
Situational expectancies and task values: Associations with students' effort
2017
Abstract According to expectancy-value theory, expectancies and task values are precursors for investing effort into learning. To date, it remains largely unknown (1) to what extent expectancies and values change from one learning situation to another and (2) to what extent inter-individual findings reflect intra-individual motivational processes. We applied an intensive longitudinal design in a sample of 155 pre-service teacher students attending a lecture. Across ten lessons with varying topics, students reported three times per lesson on their situational effort, expectancies, task values (intrinsic, attainment, utility), and cost. We used multilevel structural equation modeling with lea…
Joan Robinson and Keynes: finance, relative prices and the monetary circuit.
2003
Joan Robinson's views on credit and money are discussed only rarely. Of late, however, some Post-Keynesians have sought to revive these views, claiming that Robinson was one of the original contributors to the theory of endogenous money, post Keynes. This paper has two objectives. First, it seeks to develop Robinson's views on credit, money and finance and to show that not only did she have a clear understanding of the theory of endogenous money, but that she also held views akin to the theory of the monetary circuit. Second, the paper addresses Robinson's dismissal of the problem of relative prices and the conventional theory of value. Once again, it shows that Robinson's position is conne…
Extreme value theory versus traditional GARCH approaches applied to financial data: a comparative evaluation
2013
Although stock prices fluctuate, the variations are relatively small and are frequently assumed to be normally distributed on a large time scale. But sometimes these fluctuations can become determinant, especially when unforeseen large drops in asset prices are observed that could result in huge losses or even in market crashes. The evidence shows that these events happen far more often than would be expected under the generalised assumption of normally distributed financial returns. Thus it is crucial to model distribution tails properly so as to be able to predict the frequency and magnitude of extreme stock price returns. In this paper we follow the approach suggested by McNeil and Frey …
Flood Frequency Analysis for Sicily, Italy
2006
In this paper a regional flood frequency analysis based on the two-component extreme value TCEV distribution is developed using flood data recorded in Sicily. The hierarchical approach, characterized by three investigation levels for estimating the parameters of the theoretical distribution, is discussed first. The highest level of homogeneity hypothesis with regard to the skewness coefficient was verified by using a Monte Carlo technique and taking account of the separation effect proposed by Matalas et al. in 1975. This analysis also showed 1 the inability of the generalized extreme value model to reproduce the empirical cumulative distribution function CDF of the skewness coefficients, a…
Bilateral Monopoly: A Contribution by Francesco Ferrara
2009
In this paper, we propose an interpretation of the application of "cost of reproduction" of Francesco Ferrara to the exchange between two agents to highlight its relevance for the theory of bilateral monopoly. In the Teoria delle Mercedi (1863), Ferrara gives a numerical example to explain price determination in the exchange between one buyer and one seller. Here, this example is translated into a mathematical model that reproduces the fundamental issues of the neoclassical debate on the indeterminacy of price in the Cournot model (1938), and anticipates the solutions proposed by Edgeworth (1881) at the end of this debate.