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Early Detection of UV-B Induced Damages on Apple Seedlings by Fluorescence and Reflection Techniques
(2007)
This paper addresses the urgent need for international standardization of Context Metadata for e-Learning environments. In particular, E-Learning when distributed over the Internet, can synchronously and asynchronously reach a huge number of learners but also has to deal with a variety of different cultures and societies and the related complications. A lot of the differences strongly demand adaptation processes in which especially the contents are being modified to fit the needs in the targeted contexts. In our approach solving this task, we determined a list of around 160 significant possible differences and defined those as context metadata. In this paper, we show the results of our research regarding to the determination of context related influence factors as well as approaches to deal with them and present a first specification of the representing context-metadata.
This paper addresses the problem of adaptation of E-Learning to a given or proposed context. Current learning technology standards are available for various purposes, such as contents, learner profiles or learning activities, but there are no specifications to describe the context of learning scenarios. Such a description is crucial to identify change-requirements or to compare situations when learning scenarios are re-used. In this paper, we define a specification of context metadata. We show how they can be used to adapt learning scenarios from a given to a new context, in particular to identify change requirements for the internationalization of learning scenarios.
Structural and Dynamical Properties of Polystyrene Determined by Coarse-Graining MD Simulations
(2007)
We present results from a detailed study of a new, optimized coarse-grained (CG) model of polystyrene (PS) and compare it with a recently published one (Harmandaris et al., Macromolecules 2006, 39, 6708). We will explain in detail, what led us to a different mapping scheme and put that into the general framework, with special emphasis on the aspect of time mapping. The new model is tested against the structural and dynamic properties of PS, resulting from atomistic simulations.
The article presents a solution to detect rotor position at stand still condition for all types of permanent magnet brushless dc motors. The solution provides both secure and fast method for starting of the brushless motor, that is independent on the sensorless control scheme used. Nonlinearities found in standard three phase permanent magnet dc motor are used to derive the rotor position at stand still. The described solution assumes that there is availability of the neutral point of the three phase star motor windings.
Swedish wheeled mobile robots have remarkable mobility properties allowing them to rotate and translate at the same time. Being holonomic systems, their kinematics model results in the possibility of designing separate and independent position and heading trajectory tracking control laws. Nevertheless, if these control laws should be implemented in the presence of unaccounted actuator saturation, the resulting saturated linear and angular velocity commands could interfere with each other thus dramatically affecting the overall expected performance. Based on Lyapunov’s direct method, a position and heading trajectory tracking control law for Swedish wheeled robots is developed. It explicitly accounts for actuator saturation by using ideas from a prioritized task based control framework.
Programmable logic controllers (PLCs) have traditionally been used on numerous machines for control of the various processing and manufacturing steps. In response to an initiative by the Expert Committee Chemical Industry (FA CH), suitable metrics have been defined in order to permit rapid static analysis of comprehensive PLC programs. A tool was developed for this purpose which is also able to determine quality criteria. Additional to seven of the new metrics five metrics derived from Halstead and McCabe are used to determine the quality-criteria: testability, self-description, legibility and simplicity. New concepts were developed to determine and to calculate these criteria. The results are documented in hyper-language files with links to the called modules and control-graphs for each function. The tool was validated by three voluminous PLC-programs, two are from industrial projects.
In this contribution a machine vision inspection system is presented which is designed as a length measuring sensor. It is developed to be applied to a range of heat shrink tubes, varying in length, diameter and color. The challenges of this task were the precision and accuracy demands as well as the real-time applicability of the entire approach since it should be realized in regular industrial line production. In production, heat shrink tubes are cut to specific sizes from a continuous tube. A multi-measurement strategy has been developed, which measures each individual tube segment several times with sub pixel accuracy while being in the visual field. The developed approach allows for a contact-free and fully automatic control of 100% of produced heat shrink tubes according to the given requirements with a measuring precision of 0.1mm. Depending on the color, length and diameter of the tubes considered, a true positive rate of 99.99% to 100% has been reached at a true negative rate of > 99.7.
In the presented project, new approaches for the prevention of hand movements leading to hazards and for non-contact detection of fingers are intended to permit comprehensive and economical protection on circular saws. The basic principles may also be applied to other machines with manual loading and/or unloading. Two new detection principles are explained. The first is the distinction between skin and wood or other material by spectral analysis in the near infrared region. Using LED and photodiodes it is possible to detect fingers and hands reliable. With a kind of light curtain the intrusion into the dangerous zone near the blade can be prevented. The second principle is video image processing to detect persons, arms and fingers. In the first stage of development the detection of upper limb extremities within a defined hazard area by means of a computer based video image analysis is investigated.