Search results for "Series"
showing 10 items of 1193 documents
Comment améliorer la prévision des ventes pour le marketing ? Les apports de la théorie du chaos
2013
La littérature en marketing constate un décalage entre les avancées réalisées par les chercheurs qui développent de nouvelles méthodes de prévision des ventes, et l'usage massif de méthodes traditionnelles reposant sur l'hypothèse de linéarité des processus analysés. Cette recherche expose la contribution potentielle de la théorie du chaos à l'amélioration de la prévision des ventes. Une illustration de ces apports est proposée avec une application à la prévision des ventes de consoles de jeux vidéo au Japon. Les résultats mettent en évidence la capacité de la méthode proposée à détecter la présence de chaos dans la série et montrent la possibilité de préciser l'horizon de prévisibilité des…
Model selection using limiting distributions of second-order blind source separation algorithms
2015
Signals, recorded over time, are often observed as mixtures of multiple source signals. To extract relevant information from such measurements one needs to determine the mixing coefficients. In case of weakly stationary time series with uncorrelated source signals, this separation can be achieved by jointly diagonalizing sample autocovariances at different lags, and several algorithms address this task. Often the mixing estimates contain close-to-zero entries and one wants to decide whether the corresponding source signals have a relevant impact on the observations or not. To address this question of model selection we consider the recently published second-order blind identification proced…
Numerical Recovery of Source Singularities via the Radiative Transfer Equation with Partial Data
2013
The inverse source problem for the radiative transfer equation is considered, with partial data. Here we demonstrate numerical computation of the normal operator $X_{V}^{*}X_{V}$ where $X_{V}$ is the partial data solution operator to the radiative transfer equation. The numerical scheme is based in part on a forward solver designed by F. Monard and G. Bal. We will see that one can detect quite well the visible singularities of an internal optical source $f$ for generic anisotropic $k$ and $\sigma$, with or without noise added to the accessible data $X_{V}f$. In particular, we use a truncated Neumann series to estimate $X_{V}$ and $X_{V}^{*}$, which provides a good approximation of $X_{V}^{*…
How news affect the trading behavior of different categories of investors in a financial market
2015
We investigate the trading behavior of a large set of single investors trading the highly liquid Nokia stock over the period 2003-2008 with the aim of determining the relative role of endogenous and exogenous factors that may affect their behavior. As endogenous factors we consider returns and volatility, whereas the exogenous factors we use are the total daily number of news and a semantic variable based on a sentiment analysis of news. Linear regression and partial correlation analysis of data show that different categories of investors are differently correlated to these factors. Governmental and non profit organizations are weakly sensitive to news and returns or volatility, and, typica…
Ohjeita Jyväskylän yliopistosarjojen kirjoittajille :
2010
This document about the guidelines for publishing dissertation is out of date. Updated information is available in the webpage of Publishing Unit: https://kirjasto.jyu.fi/publish-and-buy/publishing-your-dissertation?set_language=en Tämä väitöskirjajulkaisemista käsittelevä dokumentti on vanhentunut. Ajanmukaiset väitöskirjajulkaisemista Jyväskylän yliopistossa koskevat ohjeet löydät Avoimen tiedon keskuksen julkaisuyksikön sivuilta https://kirjasto.jyu.fi/julkaisut/vaitoskirjojen-julkaisu
Qualitative analysis of housing demand using Google trends data
2019
Big data analytics often refer to the breakdown of huge amounts of data into a more readable and useful format. This study utilises Google Trends big data as a proxy for an analysis of housing demand. We employ a qualitative method (fuzzy set/Qualitative Comparative Analysis, fsQCA), instead of a quantitative method, for our estimate and forecast. The empirical results show that fsQCA successfully forecasts seasonal time series, even though the dataset is small in size. Our findings fill the gap in the qualitative and time series forecasting literature, and the forecasting procedure herein also offers a good standard for industry.
A hard day's night : the aftermath of psychological trauma in Grey's Anatomy
2014
Tämän tutkimuksen tarkoituksena oli tunnistaa ja kuvata tapoja, joilla fiktiiviset henkilöhahmot amerikkalaisessa sairaalasarjassa Greyn Anatomia reagoivat psykologisesti traumaattisiin kokemuksiin, sekä sitä, millainen rooli hahmojen keskinäisellä ystävyyssuhteella on parantumisprosessissa. Analyysin kohteena oli sarjan kaksi keskeistä henkilöhahmoa, Meredith Grey sekä Cristina Yang. Aineisto koostui kahdesta erillisestä tarinakaaresta: molemmat alkoivat traumaattisesta tapahtumasta ja loppuivat molempien hahmojen ns. löydettyä ratkaisun trauman aiheuttamiin ongelmiinsa. Yhteensä analysoituja jaksoja oli kuusitoista (16). Laadullisen analyysin perustana käytettiin kriittistä televisiotutki…
Defining polycentric urban areas through commuting cohesion. Through commuting cohesion in France
2013
International audience; Though the visualization of the daily commuting patterns around French urban area, we identify subcentres of commuting activities, illustrating the emergence of new urban polycentric structures. Via computed metrics on these graphs and an associated diachronic approach on the census data for the years between 1975 and 1999, we analyze the topological structure of the graph series. This analysis demonstrates the combined small world and star topology present in the data.
Identifying the Sales Patterns of Online Stores with Time Series Clustering
2018
Electronic commerce, especially in the business-to-consumer (B2C) context, has for years been a popular research topic in information systems (IS). However, the prior research on the topic has traditionally been dominated by the consumer focus instead of the business focus of online stores. For example, whereas various segmentations exist for online consumers based on their purchase behaviour, no such segmentations have been developed for online stores based on their sales patterns. In this study, our objective is to address this gap in prior research by identifying the most typical sales patterns of online stores operating in the B2C context. By using self-organising maps (SOM) to analyse …
El Comisario Rex, una guía turística de Viena. Análisis de contenido de series de televisión
2000
Una visión turística de Viena a través de una serie de ficción.