444 research outputs found
Solving, Estimating and Selecting Nonlinear Dynamic Models without the Curse of Dimensionality
We present a comprehensive framework for Bayesian estimation of structural nonlinear dynamic economic models on sparse grids. TheSmolyak operator underlying the sparse grids approach frees global approximation from the curse of dimensionality and we apply it to a Chebyshev approximation of the model solution. The operator also eliminates the curse from Gaussian quadrature and we use it for the integrals arising from rational expectations and in three new nonlinear state space filters. The filters substantially decrease the computational burden compared to the sequential importance resampling particle filter. The posterior of the structural parameters is estimated by a new Metropolis-Hastings algorithm with mixing parallel sequences. The parallel extension improves the global maximization property of the algorithm, simplifies the choice of the innovation variances, allows for unbiased convergence diagnostics and for a simple implementation of the estimation on parallel computers. Finally, we provide all algorithms in the open source software JBendge4 for the solution and estimation of a general class of models.Dynamic Stochastic General Equilibrium (DSGE) Models, Bayesian Time Series Econometrics, Curse of Dimensionality
JBendge: An Object-Oriented System for Solving, Estimating and Selecting Nonlinear Dynamic Models
We present an object-oriented software framework allowing to specify, solve, and estimate nonlinear dynamic general equilibrium (DSGE) models. The imple- mented solution methods for nding the unknown policy function are the standard linearization around the deterministic steady state, and a function iterator using a multivariate global Chebyshev polynomial approximation with the Smolyak op- erator to overcome the course of dimensionality. The operator is also useful for numerical integration and we use it for the integrals arising in rational expecta- tions and in nonlinear state space lters. The estimation step is done by a parallel Metropolis-Hastings (MH) algorithm, using a linear or nonlinear lter. Implemented are the Kalman, Extended Kalman, Particle, Smolyak Kalman, Smolyak Sum, and Smolyak Kalman Particle lters. The MH sampling step can be interactively moni- tored and controlled by sequence and statistics plots. The number of parallel threads can be adjusted to benet from multiprocessor environments. JBendge is based on the framework JStatCom, which provides a standardized ap- plication interface. All tasks are supported by an elaborate multi-threaded graphical user interface (GUI) with project management and data handling facilities.Dynamic Stochastic General Equilibrium (DSGE) Models, Bayesian Time Series Econometrics, Java, Software Development
Solar Updraft Power Technology: Fighting Global Warming and Rising Energy Costs
Solar updraft power technology (SUPT) forms a highly innovative, modern and efficient concept for solar-based electricity generation. Solar updraft power plants (SUPPs) are fueled purely by solar irradiation. They require no water for power generation, so their ideal locations are deserts. A SUPP consists of the glass-covered collector area (CA), in its centre the solar chimney (SC), and around the SC's perimeter the power conversion units (PCU). This arrangement causes a permanent flow of warm air through the SUPP, producing electricity. The paper describes computer simulation concepts to evaluate the power/energy harvest in such plants, based on fluid-thermodynamics and radiation-physics. The nonlinear numerical processes for the SUPPs' power harvests are solved by fast computer algorithms. Finally, the high economy of SUPT for world-wide arid zones in terms of leveled electricity costs (LECs) is exemplified by several optimized SUPPs
Using Interactive Web Tools in Environmental Planning to Improve Communication about Sustainable Development
Public involvement in the landscape planning process is an essential opportunity to communicate the goals and objectives of a sustainable planning. However, it is also important to accommodate citizen’s attitudes and perceptions of sustainability on a local or regional scale in the decision-making process. This involvement can be supported by interactive information, discussion, and learning opportunities. This article examines how communication in the context of environmental issues can be supported by modern web tools, social media, and new visualization approaches. Furthermore, the potential of social media to support communication about sustainability on a local scale and the prerequisites for its use in the planning process are discussed. Using a case study about citizens’ response to the development of intensive livestock farming in rural setting, we examine what the perception of sustainability on local scale could mean for citizens. Another case study about interactive landscape planning illustrates how such tools can promote communication about environmental issues and local sustainability. Using a framework for the use of social media, we suggest different application levels of social media in participatory planning. Finally, the opportunities to support sustainable decisions with landscape visualization in environmental planning and decision-making issues are discussed.DF
Untersuchungen zur Renaturierung und Aufreinigung von BMP-2 und BMP-4 aus Escherichia coli
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Bürger werden initiativ: Akteurssoziologische Hintergründe eines lokalen Protests aufgrund eines formalen und symbolischen Beteiligungsdefizits
Die vorliegende Arbeit untersucht lokale Beteiligungsdefizite und hieraus resultierende Proteste von Bürgerinnen und Bürgern insbesondere in ländlichen Räumen anhand eines Konfliktes um Massentierhaltung und Bauvorhaben in diesem Kontext. Sie möchte zu einem verbesserten Verständnis über Beteiligungsdefizite und ihre sozio-politischen Hintergründe beitragen. Ausgehend von der Betrachtung eines Einzelfalls der Ansiedlung eines Schlachthofs mit Erläuterung des Planverfahrens und des dazugehörigen Beteiligungs- und Entscheidungsprozesses wird der lokale Konflikt im Sinne einer politischen Soziologie analysiert, die die praxeologischen Bedingungen der handelnden Akteure und ihre relationalen Bezüge zu anderen Akteuren und sozialen Strukturen in den Blick rückt. Hierdurch können tiefliegende Grundannahmen und Überzeugungen verstanden werden, die sowohl die Protestpraxis als auch politische Erwartungen beeinflussen und jeweils in bestimmten sozialen Kontexten (Milieus) entstanden sind. Die Fallstudie dient als illustratives Beispiel, um zu zeigen, wie individuelle bzw. gruppenspezifische Belange in einem politischen Konflikt entstehen, wie abhängig diese von ihrem sozialen Kontext sind und welche Beteiligungswege (repräsentativ, informell, direkt) möglich sind, um mit ihnen angemessen umzugehen. Hierdurch wird Wissen generiert, um für einen adäquaten politischen Umgang mit diesen Belangen Empfehlungen aussprechen zu können
System measure for persistence in holographic recording and application to singly-doped and doubly-doped lithium niobate
Тестування як засіб контролю студентів в дистанційних курсах
Some questions of electronic testing in distance learning are concerned in the article: its importance in checking students’ knowledge, the main spheres of tests usage, testing possibilities in the virtual educational environment "Web-Class-KPI", special moments in criteria testings
Der Beitrag computerorientierter Elementmethoden zur Steigerung der Tragwerkssicherheit bei Schalentragwerken
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