A variational approach to path estimation and parameter inference of hidden diffusion processes

We consider a hidden Markov model, where the signal process, given by a diffusion, is only indirectly observed through some noisy measurements. The article develops a variational method for approximating the hidden states of the signal process given the full set of observations. This, in particular, leads to systematic approximations of the smoothing densities of the signal process. The paper then demonstrates how an efficient inference scheme, based on this variational approach to the approximation of the hidden states, can be designed to estimate the unknown parameters of stochastic differential equations. Two examples at the end illustrate the efficacy and the accuracy of the presented method.Comment: 37 pages, 2 figures, revise

Controller evaluations of the descent advisor automation aid

An automation aid to assist air traffic controllers in efficiently spacing traffic and meeting arrival times at a fix has been developed at NASA Ames Research Center. The automation aid, referred to as the descent advisor (DA), is based on accurate models of aircraft performance and weather conditions. The DA generates suggested clearances, including both top-of-descent point and speed profile data, for one or more aircraft in order to achieve specific time or distance separation objectives. The DA algorithm is interfaced with a mouse-based, menu-driven controller display that allows the air traffic controller to interactively use its accurate predictive capability to resolve conflicts and issue advisories to arrival aircraft. This paper focuses on operational issues concerning the utilization of the DA, specifically, how the DA can be used for prediction, intrail spacing, and metering. In order to evaluate the DA, a real time simulation was conducted using both current and retired controller subjects. Controllers operated in teams of two, as they do in the present environment; issues of training and team interaction will be discussed. Evaluations by controllers indicated considerable enthusiasm for the DA aid, and provided specific recommendations for using the tool effectively

The Impact of ICT Usage, Workplace Organisation and Human Capital on the Provision of Apprenticeship Training: A firm-level analysis based on Swiss panel data: a firm-level analysis based on Swiss panel data

Firstly, we investigated the determinants of a) the propensity of Swiss firms to provide apprenticeship training, and b) the intensity of training (measured by the employment share of apprentices). We primarily were interested in the relevance as explanatory factors of the three constituent elements of the “new firm paradigm” that emerged in the course of the last twenty years: intensive usage of ICT; redesign of workplace organisation; shift from lower to higher skills. We found that the skill composition of the workforce (including further training), ICT intensity and, to a lesser extent, workplace organisation are important drivers of apprenticeship-based skill formation, with stronger effects on training propensity than on training intensity. Secondly, we analysed the relationship between apprenticeship training and firm performance. It turned out that productivity and apprenticeships (training propensity or intensity) are negatively correlated. The study is relevant for training policy in advanced economies where the new firm paradigm plays a large and growing role

Didaktisch-methodische Perspektiven auf nationale Stereotype: Facetten einer unterrichtspraktischen Konkretisierung

In this article we address a central theme of how lessons in German and Danish that sensitise students for national clichés (stereotypes) can be designed. By introducing the training aids that support a language teaching about German and Danish clichés, we move concrete materials and results from teaching lessons in German and Danish schools as well as other educational institutions in the centre of our focus. Programmatically, a didactic-methodical model of sensitisation, reflexion and criticism is explained. Theoretical and terminological differentiations on the subject areas stereotype and stereotyping and to dimensions of stereotypes refer to the topical linguistic and social-psychological research discussion. Thoughts on the verisi-militude of national stereotypes from a didactic view decide the contribution

An adaptive discretization method solving semi-infinite optimization problems with quadratic rate of convergence

Semi-infinite programming can be used to model a large variety of complex optimization problems. The simple description of such problems comes at a price: semi-infinite problems are often harder to solve than finite nonlinear problems. In this paper we combine a classical adaptive discretization method developed by Blankenship and Falk and techniques regarding a semi-infinite optimization problem as a bi-level optimization problem. We develop a new adaptive discretization method which combines the advantages of both techniques and exhibits a quadratic rate of convergence. We further show that a limit of the iterates is a stationary point, if the iterates are stationary points of the approximate problems