TY - BOOK A1 - Strohe, Hans Gerhard T1 - Dynamic latent variables path models : an alternative PLS estimation N2 - In this paper a partial least squares (PLS) approach to dynamic modelling with latent variables is proposed. Let Y be a matrix of manifest variables and H the matrix of the corresponding latent variables. And let H = BH+ε be a structural PLS model with a coefficient matrix B. Then this model can be made a dynamic one by substituting for B a matrix F = B + CL containing the lag operator L. Then the structural dynamic model H = FH+ε is formally estimated like an ordinary PLS model. In an exploratory way the model can be used for forecasting purposes. The procedure is being programmed in ISP. T3 - Statistische Diskussionsbeiträge - 01 KW - PLS KW - dynamic models KW - path models Y1 - 1995 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-29498 ER - TY - BOOK A1 - Ruge, Marcus A1 - Strohe, Hans Gerhard T1 - Analyse von Erwartungen in der Volkswirtschaft mit Partial-Least-Squares-Modellen T1 - Analysis of expectations in the economy with Partial Least Squares Models N2 - Der statistische Diskussionbeitrag untersucht, ob und wie sich Erwartungen und Stimmungen in der Wirtschaft bilden bzw. von welchen volkswirtschaftlichen Größen sie abhängen. Als Methodik werden Partial Least Squares (PLS) Modelle genutzt, eine Modellklasse der Pfadanalyse mit latenten Variablen. Die verwendeten Daten wurden vom Ifo-Institut und aus der amtlichen Statistik entnommen. N2 - This paper analyses the development of sentiments and expectations in the German economy. The issue is how these expectatons are influenced by major macroeconomic variables like investments or unemployment. Several Partial Least Squares models (PLS) are used to estimate the relations. The data is derived from the German Ifo Institut and the official statistic. T3 - Statistische Diskussionsbeiträge - 29 KW - PLS KW - LISREL KW - Erwartungen KW - Ifo KW - Wirtschaft KW - expectations KW - PLS KW - economy KW - Germany Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-27010 ER - TY - THES A1 - Ruge, Marcus T1 - Stimmungen und Erwartungen im System der Märkte : eine Analyse mit DPLS-Modellen T1 - Sentiments and expectations in the system of markets : an analysis with DPLS models N2 - Diese Forschungsarbeit widmet sich der Analyse von Stimmungen und Erwartungen im System der Märkte mit Dynamic Partial Least Squares (DPLS) Modellen. Die Analyse komplexer Systeme mit umfangreichen Datensätzen und die Erkennung relevanter Muster erfordern die Verwendung moderner statistischer Verfahren. DPLS-Modelle, eine Variante der Strukturgleichungs-modelle mit Latenten Variablen, werden methodisch erweitert, um mehrere zeitliche Verzögerungsstufen gleichzeitig modellieren zu können. Die ökonometrischen Modelle versuchen, zahlreiche latente Einflussfaktoren und ihre verdeckten Beziehungen zu identifizieren. Als Daten werden rund 80 Indikatoren verwendet von Januar 1991 bis Juni 2010, um Stimmungen, Erwartungen und wirtschaftlich relevanten Größen zu operationalisieren und die Zusammenhänge detailliert zu untersuchen. Die Modellergebnisse zeigen, dass Stimmungen, also die Einschätzung der aktuellen wirtschaftlichen Lage, deutlich mit wirtschaftlichen Größen zusammenhängen, unter anderem mit Investitionen, Auftragseingängen oder Aktienmarktentwicklungen. Die Erwartungen, also die Einschätzung der zukünftigen Entwicklung, bieten eine mittlere bis schwache Prognosekraft für sechs bis maximal achtzehn Monate in die Zukunft. Für kürzere Zeiträume von sechs Monaten sind Stimmungen und Erwartungen die besten verfügbaren Prognosevariablen. Die Analyse der Modellabweichungen erlaubt Rückschlüsse auf wirtschaftstheoretische Konzepte, wie Rationalität der Erwartungen. Auffällig sind scheinbare Phasen der systematischen Über- und Unterbewertungen der aktuellen Situation oder zukünftigen Entwicklung, insbesondere vor und nach Krisensituationen. Die Ergebnisse dieser Arbeit geben somit einen erweiterten Einblick in die empirischen Zusammenhänge subjektiver Einschätzungen mit realen wirtschaftlichen Größen. N2 - This research thesis is devoted to the analysis of sentiments and expectations in the system of economic markets with Dynamic Partial Least Squares (DPLS) models with time-series. The analysis of complex systems with large data sets and discovering relevant patterns require the use of modern statistical methods. The DPLS models, a variant of structural equation models with latent variables, are methodically extended to include multiple lags simultaneously. The econometric models try to identify a large number of latent factors and their unobservable relations. The data consists of about 80 indicators from January 1991 to June 2010 to quantify sentiments, expectations and economically relevant variables and examine the relations in detail. The results show, that the sentiments, the assessment of the current economic situation, are clearly linked with economic variables like investments, incoming orders and stock market developments. The expectations, the assessment of future development, provide a weak to moderate predictive power for up to 18 months in the future. For shorter periods of six months sentiments and expectations are the best available forecast variables. The analysis of model deviations allows to draw conclusions about theoretical concepts such as rationality of expectations. There seem to be phases of systematic over- and undervaluation of the current situation and future development, especially before and after economic crisis. The results should provide a deeper insight into the empirical relationships between subjective assessments and real economic variables. T3 - Potsdamer Schriften zu Statistik und Wirtschaft - 1 KW - Stimmungen KW - Erwartungen KW - Wirtschaft KW - PLS KW - DPLS KW - sentiments KW - expectations KW - economy KW - PLS KW - DPLS Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-52900 SN - 978-3-86956-142-4 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Zude, Manuela A1 - Pflanz, Michael A1 - Spinelli, Lorenzo A1 - Dosche, Carsten A1 - Torricelli, Alessandro T1 - Non-destructive analysis of anthocyanins in cherries by means of Lambert-Beer and multivariate regression based on spectroscopy and scatter correction using time-resolved analysis JF - Journal of food engineering N2 - In high-value sweet cherry (Prunus avium), the red coloration - determined by the anthocyanins content - is correlated with the fruit ripeness stage and market value. Non-destructive spectroscopy has been introduced in practice and may be utilized as a tool to assess the fruit pigments in the supply chain processes. From the fruit spectrum in the visible (Vis) wavelength range, the pigment contents are analyzed separately at their specific absorbance wavelengths. A drawback of the method is the need for re-calibration due to varying optical properties of the fruit tissue. In order to correct for the scattering differences, most often the spectral intensity in the visible spectrum is normalized by wavelengths in the near infrared (NIR) range, or pre-processing methods are applied in multivariate calibrations. In the present study, the influence of the fruit scattering properties on the Vis/NIR fruit spectrum were corrected by the effective pathlength in the fruit tissue obtained from time-resolved readings of the distribution of time-of-flight (DTOF). Pigment analysis was carried out according to Lambert-Beer law, considering fruit spectral intensities, effective pathlength, and refractive index. Results were compared to commonly applied linear color and multivariate partial least squares (PLS) regression analysis. The approaches were validated on fruits at different ripeness stages, providing variation in the scattering coefficient and refractive index exceeding the calibration sample set. In the validation, the measuring uncertainty of non-destructively analyzing fruits with Vis/NIR spectra by means of PLS or Lambert-Beer in comparison with combined application of Vis/NIR spectroscopy and DTOF measurements showed a dramatic bias reduction as well as enhanced coefficients of determination when using both, the spectral intensities and apparent information on the scattering influence by means of DTOF readings. Corrections for the refractive index did not render improved results. KW - Cherry KW - DTOF KW - Effective pathlength KW - Fruit maturity KW - Lambert-Beer KW - NIR KW - Non-invasive KW - Pigments KW - PLS KW - Ripeness KW - Sensor fusion KW - Spectroscopy KW - Time-resolved spectroscopy KW - TIRF KW - Vis KW - Scattering Y1 - 2011 U6 - https://doi.org/10.1016/j.jfoodeng.2010.09.021 SN - 0260-8774 VL - 103 IS - 1 SP - 68 EP - 75 PB - Elsevier CY - Oxford ER -