Open Access

The paper demonstrates how the E–stability principle introduced by Evans and Honkapohja can be applied to models with heterogeneous and private information in order to assess the stability of rational expectations equilibria under learning. The paper extends already known stability results for the Grossman and Stiglitz model to a more general case with many differentially informed agents and to the case where information is endogenously acquired by optimizing agents. In both cases it turns out that the rational expectations equilibrium of the model is inherently E-stable and thus locally stable under recursive least squares learning.

In dieser Diplomarbeit ist die Entwicklung eines Software-Tools zur Erzeugung von Datenpunkten in einem Prozessvisualisierungssystem beschrieben. Die Software beschränkt sich zum einen auf die iFIX TM als Visualisierungssoftware und zum anderen auf Visual Basic for Application als Programmiersprache. Mit Hilfe von diesem Tool werden alle nötigen Tags sowohl in der Datenbank als auch im OPC-Client von iFIX TM erzeugt. Die Erzeugung dieser Tags ist auf die Standardelemente begrenzt. Die Erstellung dieser Verknüpfungen soll mit möglichst wenig Wissen über die Anlage selbst und über den vor Ort herrschenden Standard erfolgen. Zusätzlich soll die Bedienung des Tools intuitiv und praxisnah sein. Die entwickelte Anwendung soll in den von der GEA TBS gebauten Anlage eingesetzt werden, um dem Anwender des Programms das Verknüpfen von neuen Bauteilen in einem bestehenden Prozessvisualisierungssystems zu erleichtern und dadurch Entwicklungszeit zu sparen.

El-Salam Canal Project aims at increasing the Egyptian agricultural productivity through agricultural and stock development by irrigating about 263,500 ha gross of new lands. In order to stretch the limited water supply to cover these reclaimed areas, fresh River Nile water is augmented with agriculture drainage water from Hadus and Lower Serw drains to meet crop requirements, especially during summer months (peak demand). With a growing population and intensified industrial and agricultural activities, water pollution is spreading in Egypt, especially in main drains, which receive almost all kinds of wastes (municipal, rural, domestic and industrial wastes). The medical records indicate that significant numbers of waterborne-disease cases (bilharzias, typhoid, paratyphoid, diarrhoea, hepatitis A, B and C) have been reported in many areas in Egypt (MOHP, 2000). The National Water Quality Monitoring Program (NWQMP) in Egypt covers the Nile River, irrigation canals, drains and groundwater aquifers to assess the status of water quality for different water uses and users. The overall objective of this research is to introduce a rationalization technique for the drainage water quality-monitoring network for Hadus drain as a main feeder of El-Salam Canal Project. Later on, this technique can be applied for other parts in the NWQMP. The rationalization process started firstly with assessing and reformulating the current objectives of the network. Then, the monitoring locations were identified using integrated logical and statistical approaches. Finally, a sampling frequency regime was recommended to facilitate proper and integrated information management. The monitoring objectives were classified into three classes: design oriented, short-term and long-term deductible objectives. Mainly, the objectives “assess compliance with standards”, “define water quality problems”, “determine fate and transport of pollutants”, “make waste-load allocations” and “detect possible trends” were considered in the redesign process of the network. A combination of uni-, bi-, and multi-variate statistical techniques supported by spatial and temporal analysis for the important tributaries (key players) in Hadus drain system, were used for locating the monitoring sites. The key players analysis was carried out in the light of monitoring objectives. As a result, the monitoring network was divided into three priority levels (Layers I, II and III) as following: Layer I: It has the highest priority level and includes eight monitoring locations Layer II: It has the second priority level and includes three monitoring locations Layer III: It has the lowest priority level and includes five monitoring locations Using the method proposed by Lettenmaier (1976), the sampling frequencies were initially estimated and then evaluated for 36 water quality parameters, which were collected on monthly basis during the period from August 1997 to January 2005. The evaluation process was carried out by generating new data sets (subsets) from the original data. Then, the common required statistics from the monitoring network were extracted. The information obtained from different data sets was assessed using visual and statistical comparisons. Three integrated validation methods were employed to ensure that any decisions concerning the proposed program would not affect its ability to accomplish the monitoring objectives. These validation methods employed: descriptive statistics, regression analysis and linear multiple regression in an integrated approach. The validation results ensured that excluding the monitoring locations in layer III did not significantly affect the information produced by the monitoring network. Therefore, a monitoring network including only 11 sites (out of 16) representing the layers I and II was recommended. Based on the evaluation of sampling frequencies, it is recommended to have 6 (instead of 12) samples per year for 18 water quality parameters (COD, TSS, TVS, N-NO3, Pb, Ca, Na, Cl, Visib, BOD, Cu, Fe, Mn, pH, TDS, K, SO4_m and DO). The measured parameter SO4m will automatically replace the SO4 (calculated). SAR and Adj. SAR also can be calculated from the other parameters. For the other fifteen parameters (Mg, EC, Br, Ni, Sal, Cd, TN, TP, Temp, Fecal, Coli and N-NH4, Zn, P and Turb), it is recommended to continue with twelve samples per year. These recommendations may ensure significant reduction in the total cost of the monitoring network. This facilitates a fiscal resource, which is a key prerequisite in developing a successful program. The rescued budget can be redirected to achieve better performance in terms of improving the current resources. In addition, a frame of stakeholders-participation mechanism was proposed to not only facilitate a better coordination among the Egyptian Ministries involved in the water sector but also guarantee effective landowners/farmers involvement. However, applying such a mechanism requires more detailed studies of all the previous experiences gained by many projects trying to achieve better integration between objectives, plans and activities for the different environmental institutions in Egypt.

Die vorliegende Längsschnittuntersuchung der BA-geförderten Gründungskohorte des zweiten Halbjahres 2003 im Agenturbezirk Uelzen vergleicht mittels einer schriftlichen Befragung drei Jahre nach Gründungsbeginn schwerpunktmäßig ÜG- und ExGZ-Gründungen hinsichtlich erfolgsbezogener Merkmale. Zusätzlich werden die im Rahmen der Befragung erhobenen Informationen zur Gründungsmotivation, Gründungsvorbereitung, den finanziellen Rahmenbedingungen und der Bedeutung bestimmter Förderbedingungen für die Gründer ausgewertet. Bei einer Rücklaufquote von ca. 19 Prozent liegen 32 verwertbare ÜG- und 43 ExGZ-Fragebögen vor. Zur Überprüfung der Unterschiede von ÜG- und ExGZ-Gründungen werden T-Tests genutzt. Die Ergebnisse bestätigen erneut das Vorliegen einiger signifikanter Unterschiede zwischen ÜG- und ExGZGründungen.

This paper aims to determine if the contingent valuation method (CVM) can provide valid results useful in policy-making. This will be investigated by using a CV study that captures the willingness to pay (WTP) for the municipal cultural supply in Lueneburg, Germany. In contrast to previous CV studies that included a wide range of descriptive statistics, the empirical analysis of the current study focuses on multivariate analysis to explore the factors associated with the WTP. The results reflect current hypotheses in cultural economics. Thus, higher education levels and higher income are positively correlated with higher WTP. While the results indicate a highly significant impact of non-use values on the WTP for cultural goods across the different regression models, the findings for some variables differ considerably in magnitude across different regression models.