Ein Beitrag zur störgrößenreduzierten Erfassung und Beurteilung der Anwendungseignung im Kontext der nutzerzentrierten Produktentwicklung von Power-Tools = A contribution to the disturbance-reduced recording and evaluation of usability in the context of user-centered product development of power tools

In der vorliegenden Arbeit wird das Problem der Störgrößeneinwirkung bei der Erfassung und Beurteilung der wahrgenommenen Anwendungseignung von Power-Tools untersucht. Durch den Einfluss von Störgrößen kommt es zu einer Verzerrung der objektiven Anwendungseignung eines Power-Tools, weshalb im Sinne einer nutzerzentrierten Produktentwicklung auf Basis der wahrgenommenen Anwendungseignung keine optimalen Produkte entwickelt werden können. Die Beantwortung der folgenden Forschungsfrage steht im Fokus dieser Arbeit: Wie kann der Einfluss von Störgrößen bei der Erfassung und Bewertung der empfundenen Anwendungseignung eines Power-Tools reduziert werden und wie kann dieses Wissen in der nutzerzentrierten Produktentwicklung angewandt werden? Motiviert aus dem Stand der Forschung werden drei Haupthypothesen (H1-H3) aufgestellt, welche durch experimentelle Probandenstudien überprüft werden. Hierbei wird innerhalb einer Vorstudie (H1) zunächst der Bedarf zur Reduzierung des Einflusses von Störgrößen auf die empfundene Anwendungseignung konkretisiert, wobei sich zeigt, dass mit aktuellen Methoden relevante Usability-Aspekte, welche einen signifikanten Einfluss auf die Anwendungseignung haben, nur bedingt identifiziert werden können. Weiterhin kann anhand der Ergebnisse der Probandenbewertungen die signifikante Beeinflussung der Anwendungseignung durch den Markeneinfluss der Power-Tools und dem unterschiedlichen Grad der Expertise in der Anwendung der Anwender gezeigt werden. Zur Verringerung dieses Einflusses werden Ansätze zur Störgrößenreduzierung entwickelt. Hierbei werden am Beispiel von Trockenbauschraubern Schulungskonzepte entwickelt, mit Hilfe derer der Einfluss der unterschiedlichen Expertise reduziert werden kann (H2.1). Zur Analyse des Einflusses der Marke wird innerhalb einer Blindtest Studie, am Beispiel von Akkuschraubern, Möglichkeiten zur Vermeidung des Einflusses der Marke analysiert und Reduktionsansätze abgeleitet (H2.2). Zur Überprüfung der Anwendbarkeit und Übertragbarkeit der entwickelten Reduktionsansätze wird eine Verifizierungsstudie aufgebaut, innerhalb welcher die Anwendungseignung der Griffergonomie von Akkuschraubern bewertet wird (H3.1). Anhand der Ergebnisse der Studie kann die Leistungsfähigkeit der Reduktionsansätze gezeigt werden, wobei sowohl der Einfluss der Marke als auch der der Expertise deutlich reduziert werden konnte. Weiterhin konnte ein Ansatz zur Identifizierung unbekannter Störgrößen aufgebaut werden, welcher bei der Erfassung und Aufbereitung von Versuchsdaten unterstützt. Die entwickelten Forschungsansätze liefern einen Beitrag zur störgrößenreduzierten und damit objektiveren Erfassung der Anwendungseignung von Power-Tools, wodurch deren Entwicklung auf die individuellen Anforderungen der Anwender optimiert werden kan

User-centered design of power tools: a generic process for evaluation of usability aspects [Die Nutzerzentrierte Produktentwicklung von Power-Tools: Ein generischer Prozess zur Untersuchung von Usability-Aspekten]

User-centered design focuses on the individual needs of the product users. The aim is to adjust the design of the product according to the requirements of the user and application. Existing methods for evaluation of the perceived usability are often limited to one specific aspect, and it requires a high effort to transfer the respective method to other aspects. A generic process for the evaluation of the perceived usability is missing. This paper presents the generic Usability Study Evaluation Process (USE-Process) that helps product designers to identify and evaluate usability aspects relevant to the suitability of the usage of a product. The process is divided into three sections: 1. A structured field study to identify the relevant usability aspects; 2. A generic study design for the subjective evaluation of usability aspects under objective and reproducible conditions; 3. The use of measurement tools that help to quantify the results of the subjective evaluation. The generic applicability of the process is shown by the example of the evaluation of cordless screwdrivers; several usability aspects were identified, clustered, and evaluated by using subjective evaluation methods and measurement techniques

How to use human pose estimation to measure the hand-arm motion in craft application with no influence on the natural user behavior

The interaction between human and machine plays an important role in the design and optimization of human-machine systems. This interaction is characterized by human motion using the technical system. Especially in the field of hand and power tool applications, the motion capture should be performed under the real working condition and without influencing the user. There are already motion tracking systems that allow capturing the motion during the interaction, but there is no mobile motion capture system that allows an individual analysis of the user for biomechanical analysis in the normal work process without influencing him. Therefore, requirements for a motion capture system are derived and a system is presented that meets these requirements. This system consists of two cameras and is based on the pose estimation algorithm OpenPose. The comparison of the presented system and the state-of-the-art system Xsens is performed and based on the measured elbow angle and the wrist position. The results show a very good correspondence between the curve characteristic of the elbow angle and the wrist position of both systems. However, inexplicable values shifting at two different levels still occur, which need to be investigated further. Overall, the presented system shows great potential in terms of mobility and flexibility of the presented system with some weaknesses in the data processing and efficiency. By addressing these weaknesses, the presented system can be used in the analysis and optimization of human-machine systems

Meaningful Prediction Parameters for Evaluating the Suitability of Power Tools for Usage

During the usage of power tools, user and power tool are interacting strongly with each other, which is why the working result depends heavily on the usability of a power tool depending on the application (Suitability of Usage (SoU)). The optimization of power tools, in terms of the usercentered design, therefore aims at an increase of the SoU. So far, the acquisition of the SoU is done within broad application tests, with several users and different application situations. Hereby, problems occur because it is often difficult to find an adequate mix of professional trained participants, which are able to evaluate the SoU objectively. To investigate the differences between professional power tool users and trained non-professional users, a study has been performed. In this study, 20 professional and 19 non-professional users tested power tools (cordless screwdrivers and impact wrenches, three different manufacturer each) and evaluated the handles of these systems according to fourteen test items, divided into an observation and a usage phase. By the use of statistical variance analysis, the captured data has been analyzed to investigate the influence on the evaluation through the usage experience of the users. Results indicates a strong influence within the evaluation categories where evaluations are done which rely on long term experiences, like the evaluation of the distributed force on the fingers. To produce further increase in efficiency and objectivity, a categorical regression by the use of Lasso models has been performed to identify the most meaningful influencing predictors for the SoU level. The investigation is carried out using the example of the evaluation of discomfort on the handle. Results indicates that the most meaningful predictor for the evaluation of the handle is the circumference of the handle at the position of the middle finger

Factors on Vibrational Harm during Hammer Drilling : Influences of Lateral Force, Feed Force, Hammer Drill and Drill Bit Type

When using hammer drills, the user is exposed to vibrations which can cause damage to the body. Those vibrations can be affected by external factors such as feed forces, which can increase the degree of damage to the user. However, currently there is a lack of knowledge as to whether the lateral forces applied by the user also have an influence on the technical system and whether these influences depend on the system. For this reason, a study with 1152 test runs was carried out on a test rig to investigate the relationship between the feed force and the lateral force as a function of the hammer drill setup on the vibrations at the hammer drill housing and main handle. The experiment showed that the feed (p = < .001, up to r = 0.57) and lateral (p = < .001, up to r = 0.77) forces had an influence on the vibrations of the hammer drill. However, these depended strongly on the technical system and hence cannot be generalized. Furthermore, it was proven that the impact frequency of the hammer drill was reduced by increasing both the feed force (p = < .001, r = 0.55) and the lateral force (p = < .001, r = 0.23). The findings can not only be used by engineers and scientists to further develop vibration standards, but also to design more ergonomic hammer drills. Hence, the vibration decoupling of hammer drills should be redesigned so that lateral forces do not lead to an increase in vibrations that are harmful to the user

Developing surface water flood forecasting capabilities in Scotland: an operational pilot for the 2014 Commonwealth Games in Glasgow

Existing surface water flood forecasting methods in Scotland are based on indicative depth‐duration rainfall thresholds with limited understanding of the likelihood of inundation or associated impacts. Innovative risk‐based solutions are urgently needed to advance surface water forecasting capabilities for improved flood resilience in urban centres. A new model‐based solution was developed for Glasgow, linking 24‐h ensemble rainfall predictions from the Met Office Global and Regional Ensemble Prediction System for the UK (MOGREPS‐UK) with static flood risk maps through the Grid‐to‐Grid hydrological model. This new forecasting capability was used operationally by the Scottish Flood Forecasting Service during the 2014 Commonwealth Games to provide bespoke surface water flooding guidance to responders. The operational trial demonstrated the benefits of being able to provide targeted information on real‐time surface water flood risk. It also identified the high staff resource requirement to support the service due to the greater uncertainty in surface water flood forecasting compared to established fluvial and coastal methods

Leitfaden zur Anwendung empirischer Forschungsmethoden in der nutzerzentrierten Produktentwicklung : Forschung mit und an Menschen in den Ingenieurwissenschaften

Der vorliegende Leitfaden hat den Anspruch, Orientierung innerhalb des empirischen Forschungsprozesses zu bieten. Insbesondere beim Aufbau, der Durchführung und der Auswertung in an-wendungsorientierten Untersuchungen in der nutzerzentrierten Produktentwicklung, also Untersuchungen mit Probanden (User Studies), soll er unterstützen und dadurch einen Beitrag zur Steigerung der Qualität sowie der Vermeidung von Fehlern leisten. Das Besondere dieses Leitfadens ist die Zusammenführung von Wissen und wissenschaftlichen Methoden aus verschiedenen Fachbereichen mit dem Fokus auf den Menschen in der Forschung und seinen Einfluss auf die Datenerhebung. An dieser Stelle wird betont, dass kein Anspruch auf Vollständigkeit besteht. Empirische Forschungsmethoden entwickeln sich fortlaufend weiter und sollten in der Anwendung immer über-prüft, an die Forschungsfrage und damit einhergehend an die Hypothesen angepasst und diskutiert werden. Für erfolgreiche Forschungsarbeiten soll der Leitfaden ein Grundgerüst darstellen, welches die vielfältigen Forschungsmethoden der verschiedenen wissenschaftlichen Disziplinen sowie den empirischen Forschungsprozess mit Fachbegriffen aufzeigt, Hinweise gibt und für neue Anwendungsmöglichkeiten in der Produktentwicklung inspiriert. Über Fragen, Anmerkungen, Verbesserungsvorschläge oder generelles Feedback freuen sich die Autoren. Bitte wenden Sie sich dazu an Frau Diana Fotler: [email protected]

574-586 Mutations in PCBD1 cause hypomagnesemia and renal magnesium wasting

Mutations in PCBD1 are causative for transient neonatal hyperphenylalaninemia and primapterinuria (HPABH4D). Until now, HPABH4D has been regarded as a transient and benign neonatal syndrome without complications in adulthood. In our study of three adult patients with homozygous mutations in the PCBD1 gene, two patients were diagnosed with hypomagnesemia and renal Mg 2+ loss, and two patients developed diabetes with characteristics of maturity onset diabetes of the young (MODY), regardless of serum Mg2+ levels. Our results suggest that these clinical findings are related to the function of PCBD1 as a dimerization cofactor for the transcription factor HNF1B. Mutations in the HNF1B gene have been shown to cause renal malformations, hypomagnesemia, and MODY. Gene expression studies combined with immunohistochemical analysis in the kidney showed that Pcbd1 is expressed in the distal convoluted tubule (DCT), where Pcbd1 transcript levels are upregulated by a low Mg2+-containing diet. Overexpression in a human kidney cell line showed that wild-type PCBD1 binds HNF1B to costimulate the FXYD2 promoter, the activity of which is instrumental in Mg2+ reabsorption in the DCT. Of seven PCBD1 mutations previously reported in HPABH4D patients, five mutations caused proteolytic instability, leading to reduced FXYD2 promoter activity. Furthermore, cytosolic localization of PCBD1 increased when coexpressed with HNF1B mutants. Overall, our findings establish PCBD1 as a coactivator of the HNF1B-mediated transcription necessary for fine tuning FXYD2 transcription in the DCT and suggest that patients with HPABH4D should be monitored for previously unrecognized late complications, such as hypomagnesemia and MODY diabetes. Copyrigh