Flood regulation using nonlinear model predictive control

In this paper the flood problem of the river Demer, a river located in Belgium, is discussed. First a simplified model of the Demer basin is derived based on the conceptual reservoir modeling concept. This model was calibrated to simulations results with a more detailed full hydrodynamic model. Afterwards, the focus is shifted to a nonlinear model predictive controller (NMPC) which is based on a new semi-condensed optimization procedure combined with a line search approach. Finally, simulations are performed based on historical data in which the NMPC is compared with the current control strategy used by the local water administration. Uncertainties are added to the rainfall predictions in order to assess the robustness of the NMPC.     

Optical characterization of autostereoscopic 3‐D displays

Abstract— Display‐measurement methods different from conventional 2‐D display measurements are needed for verifying the optical characteristics of autostereoscopic (3‐D) displays and for comparing different 3‐D display technologies. Industry is lacking standardized measurement methods, and the reported results can not always be compared. The selected set of characteristics discussed in this paper and partly defining the quality of the 3‐D experience are crosstalk, viewing freedom, and optimum viewing distance. Also, more conventional display characteristics such as luminance are discussed, since the definitions for these characteristics in 3‐D mode usually differ from those used for the 2D displays. We have investigated how these chosen 3‐D display characteristics can be objectively measured from transmissive two‐view and multiview 3‐D displays. The scope of this article is to generally define those basic characteristics as well as the different measurement methods. Most of the 3‐D characteristics can be derived from the luminance and colors versus the viewing angle. Either a conoscopic or a goniometric measurement system can be used, as long as the angular and stray‐light properties are suitable and known. The characteristics and methods are currently discussed in the display‐quality standardization forums.     

Validating the Marschak Interaction Method Rating System with adolescent mother-child dyads.

The authors investigated the reliability and construct validity of the Marschak Interaction Method Rating System (MIMRS), a new observational scoring system for the play-based Marschak Interaction Method (MIM), particularly its ability to capture high-risk parenting in adolescent mother-child dyads. The MIMRS demonstrated high interrater reliability and high internal consistency. Convergent validity was supported by moderately negative correlations between the MIMRS and the Parenting Stress Index/Short Form. The MIMRS demonstrated good contrasted groups validity, differentiating between 15 adolescent-child dyads and 16 adult- child comparison dyads, even after adjustment for differences in children's age. These results suggest that the MIMRS has the potential be a valuable rating system for research and practice with the MIM, as well as understanding and assessing parent-child relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Guest Editorial

The extreme high speed of change in the area of information technology creates a new demand for a process of continues learning and relearning in the workplaces but also among the public as a whole. There is need for a deeper crossdisciplinary and interdisciplinary understanding of the effects of this extreme demand for learning and relearning, both on us as individuals, on public and private organization and on the society as a whole. Information technology provides to some extent possible solutions to the problems it creates. Consequently, web based learning is also expanding with an accelerating speed. But this new form of learning is not to the same extent backed up by a fast growing research, in areas like on-the job-learning, workplace pedagogics, 'competence ergonomics', etc. But there are a number of very good exceptions like the Knowledge Media Institute of the Open University, and also a number of newly established facilities like the network university in the north of Sweden, the Mid Sweden University. In this special issue these types of problems are discussed, including those where the emphasis lies in creating rational and effective methods for web-based training and learning. The following was put forward in the invitation to a particular target group for this special issue.     

Effect of number of views to the viewing experience with autostereoscopic 3‐D displays

Abstract— The observers' 3‐D viewing experience when the way the content is created and shown on an autostereoscopic 3‐D display alternate is evaluated. The observer's depth impression, and the perceived contour accuracy and image naturalness or peskiness of the content shown on a 3‐D display, has been investigated. In addition, the consequences of the way the content is created to the results from the optical characterization for the same display have been studied. The alternation of the content was realized in two different ways. Firstly, the number of views for creating the image was varied. Two, five, and 14 views were used; the main focus being on testing the same display and treating it as an ordinary two‐view and a 14‐view display with inter‐sub‐view crosstalk. Also, the intermediate condition where five views with non‐uniform view‐specific crosstalk were used has been investigated. Secondly, the way the content is created was varied by using images with computer‐generated content and photos. The effect of these parameters on viewing experience as such and especially the effect of 3‐D crosstalk on the viewing experience were studied.     

Analysis of electrically conductive silver ink on stretchable substrates under tensile load

Electrical conductors were printed by the screen printing method on stretchable PVC substrates and on fabrics. Polymer thick film silver ink was used as the conductive medium. The electrical performance and the structure of the ink film were investigated in unloaded conditions and under strain. In addition, the ink film morphology was examined. The goal of this study was to provide information for developing a strain sensor for large strain levels using the materials under investigation. An additional aim was to assist the integration of electronics into other structures. The results showed that strain sensitive structures can be made using the materials selected for this study and these materials provide an opportunity to develop strain sensors. The structures also tolerated large strain levels and thus they can be integrated into other materials which are exposed to strain.     

A new method for evaluating the subjective image quality of photographs: dynamic reference

The Dynamic Reference (DR) method has been developed for subjective image quality experiments in which original or undistorted images are unavailable. The DR method creates reference image series from test images. Reference images are presented to observers as a slide show prior to evaluating their quality. As the observers view the set of reference images, they determine the overall variation in quality within the set of test images. This study compared the performance of the DR method to that of the standardized absolute category rating (ACR) and paired comparison (PC) methods. We measured the performance of each method in terms of time effort and discriminability. The results showed that the DR method is faster than the PC method and more accurate than the ACR method. The DR method is especially suitable for experiments that require highly accurate results in a short time.