Search results for " Difference"
showing 10 items of 1369 documents
Swing options in commodity markets: a multidimensional Lévy diffusion model
2013
Author's version of an article in the journal: Mathematical Methods of Operations Research. Also available from the publisher at: http://dx.doi.org/10.1007/s00186-013-0452-7 We study valuation of swing options on commodity markets when the commodity prices are driven by multiple factors. The factors are modeled as diffusion processes driven by a multidimensional Lévy process. We set up a valuation model in terms of a dynamic programming problem where the option can be exercised continuously in time. Here, the number of swing rights is given by a total volume constraint. We analyze some general properties of the model and study the solution by analyzing the associated HJB-equation. Furthermo…
Temporal difference method for processing dynamic speckle patterns
2010
A temporal difference method for processing dynamic speckle images is proposed. In the method two speckle images of an object, separated by a time interval, are subtracted one from the other to detect whether the speckle structure has changed or not. The rationale of the method is discussed. A variant of the method that allows measuring the area of an activity zone surrounded by a static region is tested in digital simulations. As a demonstrative experiment, that variant is employed to characterize the drying of a damp patch in filter paper.
Nonlinear System Response for Impulsive Parametric Input
1997
In engineering applications when the intensity of external forces depends on the response of the system, the input is called parametric. In this paper dynamical systems subjected to a parametric deterministic impulse are dealt with. Particular attention has been devoted to the evaluation of the discontinuity of the response when the parametric impulse occurs. The usual forward difference and trapezoidal integration schemes have been shown to provide only approximated solutions of the jump of the response; hence, the exact solution has been pursued and presented under the form of a numerical series. The impulse is represented throughout the paper by means of a classical Dirac’s delta functio…
La perception des accords aromatiques : un exemple d'interactions perceptives dans les mélanges odorants
2007
Diplôme : Dr. d'Université; Dans le monde de la parfumerie et de l'aromatique, il existe un terme particulier définissant la formation d'une nouvelle qualité odorante à travers le mélange et la fusion de plusieurs odeurs : l'accord. Ce terme, largement employée parmi ces experts, n'avait jamais donné lieu à des études scientifiques approfondies.L' objectif de cette thèse a été de démontrer la réalité de l'accord en olfaction et de montrer qu'il repose sur des interactions perceptives influençant la qualité de l'odeur. Nous avons en particulier étudié les déterminants physico-chimiques, perceptifs et cognitifs des accords aromatiques. Dans un premier temps, nous avons démontré que la percept…
Ecological correlates of Spanish preschoolers’ physical activity during school recess
2017
Early childhood education (ECE) institutions may be one place for young children to obtain a significant proportion of their daily physical activity (PA). Even though young children are generally considered to be very active, and recess time is considered an important environmental factor for promoting PA, evidence suggests that young children spend most recess time participating in sedentary activities. To our knowledge there have been no systematic evaluations of the PA levels and patterns during recess time in Spanish preschool children. Therefore, the aims of this study were threefold: (a) to analyse the PA patterns and sedentary behaviour during recess time in outdoor ECE environments…
Finnish and Greek early childhood teachers’ perspectives and practices in supporting children’s autonomy
2017
Kindergarten teachers from different cultural backgrounds attribute various meanings to children’s autonomy. There seems to be cultural differences in early childhood education curricula with regard to how a child’s autonomy is described and how it is supported. This qualitative study asks: how do teachers narrate their perspective and pedagogical support of children’s autonomy, and what kinds of similarities and differences in the pedagogy and practices can be found in Finnish and Greek early childhood education (ECEC) contexts? The data of this qualitative study consist of a semi-structured questionnaire of 14 kindergarten teachers and observations of their pedagogical practices in the da…
Vegetation Types Mapping Using Multi-Temporal Landsat Images in the Google Earth Engine Platform
2021
Vegetation Types (VTs) are important managerial units, and their identification serves as essential tools for the conservation of land covers. Despite a long history of Earth observation applications to assess and monitor land covers, the quantitative detection of sparse VTs remains problematic, especially in arid and semiarid areas. This research aimed to identify appropriate multi-temporal datasets to improve the accuracy of VTs classification in a heterogeneous landscape in Central Zagros, Iran. To do so, first the Normalized Difference Vegetation Index (NDVI) temporal profile of each VT was identified in the study area for the period of 2018, 2019, and 2020. This data revealed strong se…
Relationships between climatic parameters and forest vegetation: application to burned area in Alicante (Spain)
2000
Abstract The main aims of this study is to examine the variability of normalized difference vegetation index (NDVI) on forest vegetation in Alicante (Spain) between 1984 and 1994 and to analyse the influence of climatic parameters in the regeneration of forest areas burned by fires. The zone of study is located between XUTM (m) 730400-760400 and YUTM (m) 4274000-4304000 and is characterised by a great topographic complexity that leads to diverse microclimatic conditions. In this area, the maximum annual rainfall of the Valencian Community is recorded, reaching 850 mm of average annual rainfall ( Belda, 1997 ). We examined the spatial and temporal analyse of rainfall and soil moisture over t…
Migration and Individual Earnings in Finland: A Regional Perspective
1999
Attention has recently focused on the rapidly increasing pace and regional concentration of migration in Finland. Most migrants head to the growth centre regions located mainly in the southern parts of the country. This study investigates the effects of moving on individuals, and compares the post-move incomes across the Finnish regions. Significant regional differences in the types of inmigrants and their incomes are observed. The results indicate that, in general, migrants tend to benefit from moving in the form of higher post-move incomes. In particular, individuals who move to relatively rich regions have higher levels of income succeeding the move and also experience faster income grow…
Spillovers from the oil sector to the housing market cycle
2017
We assess the spillovers from the oil sector to the housing market cycle using quarterly data for 20 net oil-exporting and -importing industrial countries, and employing continuous- and discrete-time duration models. We do not uncover a statistically significant difference in the average duration of booms and normal times in the housing markets of those net oil-importers and net oil-exporters. Similarly, the degree of exposure to commodity price fluctuations does not seem to significantly affect the housing market cycle. However, we find that housing booms are shorter when oil prices increase than housing busts when oil prices decrease. We also show that the net oil-importers are more vulne…