Christoph Tietz
Siemens
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Christoph Tietz.
Neural Networks: Tricks of the Trade (2nd ed.) | 2012
Hans-Georg Zimmermann; Christoph Tietz; Ralph Grothmann
Recurrent neural networks (RNNs) are typically considered as relatively simple architectures, which come along with complicated learning algorithms. This paper has a different view: We start from the fact that RNNs can model any high dimensional, nonlinear dynamical system. Rather than focusing on learning algorithms, we concentrate on the design of network architectures. Unfolding in time is a well-known example of this modeling philosophy. Here a temporal algorithm is transferred into an architectural framework such that the learning can be performed by an extension of standard error backpropagation.
A Quarterly Journal of Operations Research | 2011
Hans-Georg Zimmermann; Ralph Grothmann; Christoph Tietz; Holger von Jouanne-Diedrich
Business management requires precise forecasts in order to enhance the quality of planning throughout the value chain. Furthermore, the uncertainty in forecasting has to be taken into account.
A Quarterly Journal of Operations Research | 2012
Hans-Georg Zimmermann; Ralph Grothmann; Christoph Tietz
Forecasting of market prices is a basis of rational decision making [Zim94]. Especially recurrent neural networks (RNN) offer a framework for the computation of a complete temporal development. Our applications include short- (20 days) and long-term (52 weeks) forecast models. We describe neural networks (NN) along a correspondence principle, representing them in form of equations, architectures and embedded local algorithms.
Archive | 2013
Hans-Georg Zimmermann; Christoph Tietz; Ralph Grothmann
From a mathematical point of view, neural networks allow the construction of models, which are able to handle high-dimensional problems along with a high degree of nonlinearity. In this chapter we deal with a special type of time-delay recurrent neural networks. In these models we understand a part of the world as a large recursive system which is only partially observable. We model and forecast all observables, avoiding the problem in open systems that we do not know the external drivers from present time on. This framework goes far beyond the paradigms of standard regression theory and allows us to forecast financial markets and perform a new way of risk analysis.
Künstliche Intelligenz | 2012
Hans-Georg Zimmermann; Christoph Tietz; Ralph Grothmann; Thomas A. Runkler
Rational decisions are based upon forecasts. Precise forecasting has therefore a central role in business. The prediction of commodity prices or the prediction of energy load curves are prime examples. We introduce recurrent neural networks to model economic or industrial dynamic systems.
international conference on artificial neural networks | 2006
Hans Georg Zimmermann; Lorenzo Bertolini; Ralph Grothmann; Anton Maximilian Schäfer; Christoph Tietz
In econometrics, the behaviour of financial markets is described by quantitative variables. Mathematical and statistical methods are used to explore economic relationships and to forecast the future market development. However, econometric modeling is often limited to a single financial market. In the age of globalisation financial markets are highly interrelated and thus, single market analyses are misleading. In this paper we present a new way to model the dynamics of coherent financial markets. Our approach is based on so-called dynamical consistent neural networks (DCNN), which are able to map multiple scales and different sub-dynamics of the coherent market movement. Unlikely to standard econometric methods, small market movements are not treated as noise but as valuable market information. We apply the DCNN to forecast monthly movements of major foreign exchange (FX) rates. Based on the DCNN forecasts we develop a technical trading indicator to support investment decisions.
international conference on artificial neural networks | 2002
Georg Zimmermann; Ralph Grothmann; Christoph Tietz; Ralph Neuneier
In this paper, we present an explanatory multi-agent model. The agents decision making is based on cognitive systems with three basic features (perception, internal processing and action). The interaction of the agents allows us to capture the market dynamics.The three features are derived deductively from the assumption of homeostasis and constitute necessary conditions of a cognitive system. Given a changing environment, homeostasis can be seen as the attempt of a cognitive agent to maintain an internal equilibrium. We model the cognitive system with a time-delay recurrent neural network.We apply our approach to the DEM / USD FX-Market. Fitting realworld data, our approach is superior to a preset benchmark (MLP).
international conference on artificial neural networks | 1992
Alexander Linden; Christoph Tietz
Abstract We developed SESAME to make complex experiments possible, that combine different neural network and learning paradigms in an elegant way. SESAME represents an object-oriented framework in which experiments are constructed by uniform building blocks. Experiment substructures can be integrated at any place. Examples are given for Back-propagation and Feature Maps.
Archive | 2004
Ralph Grothmann; Christoph Tietz; Hans-Georg Zimmermann
the european symposium on artificial neural networks | 2002
Hans-Georg Zimmermann; Christoph Tietz; Ralph Grothmann