Description and Results: Antenna Measurement Facility Comparisons [Measurements Corner]

In recent years, formalized facility comparison activities have become important for the documentation and validation of laboratory proficiency and competence and mandatory for achieving accreditation such as that of the International Organization for Standardization (ISO) 17025 or similar organizations [1]. Different intercomparison campaigns have been conducted on antenna measurements in the framework of various European activities. Such activities were initiated in 2004 with the Sixth Framework Program of the European Union (EU) Antenna Center of Excellence (ACE) [2]. The work continued under the management of the European Association on Antennas and Propagation (EurAAP), supported by the European Cooperation in Science and Technology (COST) in the programs Antenna Systems and Sensors for Information Society Technologies (ASSIST) IC0603 and Versatile, Integrated, and Signal-Aware Technologies for Antennas (VISTA) IC1102, including still ongoing campaigns [3]-[5]. Results of these activities have led to improvements in antenna measurement procedures and protocols in facilities and standards [6], [7]. Due to the direct benefits available to the participants, the activities have been very successful, and partial outcomes have been published in IEEEreferenced articles [8]-[18]

Learning Analytics in the context of authentic, complex and multidimensional scenarios of nursing education: Chances and limitations of learning analytics in a serious game

Der Beitrag diskutiert anhand des Forschungsprojektes Game Based Learning in Nursing – Spielerisch Lernen in authentischen, digitalen Pflegesimulationen (GaBaLEARN) die Einbindung von Learning Analytics in digitale Fallsimulationen eines Serious Games. Es werden pflege- und mediendidaktische Impulse zur Entwicklung und Integration von Learning Analytics für die Darstellung von situativen, komplexen Kompetenzen im Bereich personenbezogener Dienstleistungsberufe, wie der Pflege, dargestellt.The article discusses the integration of learning analytics in digital simulations of authentic scenarios of a serious game. The principles of nursing education lead to show how authentic, complex and multidimensional narratives are used to facilitate learning processes in humanties. This takes place using the example of the research project Game Based Learning in Nursing – Spielerisch Lernen in authentischen, digitalen Pflegesimulationen

Fast spherical near-field antenna measurement methods

Spherical near-field antenna measurement is an established method for characterizing the electrical properties of antennas. Compared to far-field measurements, however, a mathematical transformation of the near-field data is necessary to determine the desired far-field characteristics. In order to obtain accurate and complete transformation results, it is necessary to acquire near-field data on a closed surface (e.g. a sphere) around the test antenna. This significantly increases the measurement time compared to far-field measurements, which is particularly relevant in view of the increase of mobile communication devices and the associated measurement burden. In this thesis, different methods for accelerating spherical near-field antenna measurements are investigated and evaluated. First, the theory of the spherical wave expansion is explained. It is shown that the transformation time is not a relevant factor for most antennas. Usually the measuring chamber is the limiting resource and, therefore, it is beneficial to increase the complexity of the transformation to reduce measurement chamber utilization. After introducing the theory and the transformation algorithms, several possibilities for accelerating the near-field measurements are investigated. A simple approach is the reduction of measurement points by truncation of the measurement surface. This method aims to determine only certain, selected areas of the far field correctly. Due to the lack of information however, approximation errors always occur. The main contribution of this thesis to the state-of-the-art is the investigation of non or minimally redundant sampling grids and the development of the associated transformation methods. It is shown that the number of measurement points can always be minimized by a suitable selection of the transformation origin. Furthermore, it is comprehensively analyzed which scanning grids enable time-efficient and accurate measurements. For this purpose, two typical measurement systems (roll-over-azimuth and robotic arm system) are considered. It is shown that the respective measuring system has a significant influence on the measurement duration depending on the different sampling grids. Using the proposed methods, a measurement time reduction between 5% and 50% has been achieved for the investigated examples. The determined uncertainties show that this does not reduce the measurement accuracy significantly. A further reduction of the measurement points leads to an underdetermined system of equations whose solution is generally not unique. However, using Compressed Sensing methods, it is still possible to correctly determine the spherical mode spectrum under certain circumstances. These methods are not covered by this thesis. In summary, different acceleration methods can be used and combined. Truncation can considerably reduce the measurement time in certain cases, but has the disadvantage that the antenna properties can only be approximated and not completely determined. In comparison, non-redundant sampling grids reduce the measurement time without significantly reducing the measurement accuracy. In general, the spherical mode spectrum can be determined with the developed methods from measured data on any closed measurement surface. The methods presented can therefore also be used to develop novel measuring systems that are adapted to the corresponding measuring task, since a spherical measuring geometry is generally not required

Correction of Non-ideal Probe Orientations for Spherical Near-Field Antenna Measurements

Spherical near-field scanning is a standard method to measure the radiation characteristic of an antenna under test (AUT). Due to the required near-field to far-field transformation of the measured data, an accurate position and orientation of the probe during the measurement is crucial. This might be difficult to achieve if, for example, a robotic arm system is used to position the probe. Different methods for correction of non-ideal measurement positions have been presented in the past. In contrast, the related non-ideal probe orientations in a spherical near-field measurement system have not been comprehensively analyzed due to the assumption that the error is small since the probe receiving pattern is typically broad (e.g. an open-ended waveguide). In this paper, it is shown that non-ideal probe orientations can be included in the spherical near-field to far-field transformation. This is achieved by additional rotations of the probe receiving coefficients in the probe response calculation. The introduced pointwise higher-order probe correction scheme allows an exact spherical wave expansion of the radiated AUT field. The proposed method is used to investigate the error due to non-ideal probe orientations by simulation and measurement. The presented results can be used to estimate the error due to non-ideal probe orientations. It is verified that the error is typically small compared to other error sources in a practical measurement even if a directive higher-order probe is used. Nevertheless, including the probe orientation generally improves the accuracy of the measurement result

Projektkunskap för främjandet av organisatoriskt lärande

Samhället, organisationer och individer är idag under ständig påverkan av information och kunskap. För att ta vara på tillgänglig kunskap och information behöver organisationer ha ett aktivt arbete med kunskapsprocesser som i sin tur stöds av olika IT-verktyg. Uppsatsen syftar till att bygga en djupare förståelse för hur IT-konsultföretag jobbar med dessa processer och system för att hantera projektkunskap. Utifrån relevant litteratur sammanställs ett antal kategorier och faktorer som i sin tur ligger till grund för de kvalitativa undersökningsmetoder som används. Dessa genomförs med fem respondenter som har lång erfarenhet inom konsultföretag som erbjuder tjänster inom IT-sektorn. De undersökta IT-konsultföretagen har många olika initiativ för att främja organisatoriskt lärande men det finns förbättringsområden på hur projektkunskap skall hanteras systematiskt i organisationen