Deutschsprachige Fragebögen zur Usability-Evaluation im Vergleich

Für die Konstruktion gebrauchstauglicher Anwendungssysteme ist eine exakte Evaluierung der Usability eine wertvolle Unterstützung. Zu diesem Zweck werden in der Praxis häufig Usability-Fragebögen herangezogen. Im deutschen Sprachraum sind die beiden Fragebögen Isonorm 9241/10 und Isometrics, die beide Software gemäß der EN ISO 9241-110 evaluieren, weit verbreitet. Die vorliegende Studie widmete sich einem Vergleich dieser beiden Fragebögen hinsichtlich testtheoretischer Gütekriterien. Im Rahmen eines experimentellen Designs wurden die beiden Fragebögen eingesetzt um die Usability von zwei Standard-Softwarepaketen zu bewerten. Hinsichtlich der inhaltlichen Validität der Fragebögen zeigten die Ergebnisse eine hohe Übereinstimmung der Usability-Messung der beiden Fragebögen. Auch weitere testtheoretische Analysen lieferten eine ähnliche Qualitätsbeurteilung beider Fragebögen, weshalb sie aus diesem Blickwinkel gleichermaßen für Forschung und Praxis empfohlen werden können

Process Innovation as Creative Problem-Solving: An Experimental Study of Textual Descriptions and Diagrams

The use of process models to support business analysts' idea-generation tasks has been a long-standing topic of interest in process improvement. We examine how two types of representations of organizational processes - textual and diagrammatic - assist analysts in developing innovative solutions to process-redesign tasks. The results of our study clarify the types of process-redesign ideas generated by analysts who work with text versus those who work with models. We find that the volume and originality of process-redesign ideas do not differ significantly but that appropriateness of ideas varies. We discuss the implications of these findings for research and practice in process improvement

Identifying Emotions in Social Media: Comparison of Word-emotion lexica

In recent years, emotions expressed in social media messages have become a vivid research topic due to their influence on the spread of misinformation and online radicalization over online social networks. Thus, it is important to correctly identify emotions in order to make inferences from social media messages. In this paper, we report on the performance of three publicly available word-emotion lexicons (NRC, DepecheMood, EmoSenticNet) over a set of Facebook and Twitter messages. To this end, we designed and implemented an algorithm that applies natural language processing (NLP) techniques along with a number of heuristics that reflect the way humans naturally assess emotions in written texts. In order to evaluate the appropriateness of the obtained emotion scores, we conducted a questionnaire-based survey with human raters. Our results show that there are noticeable differences between the performance of the lexicons as well as with respect to emotion scores the human raters provided in our surve

Visual modelling and designing for cooperative learning and development of team competences

This paper proposes a holistic approach to designing for the promotion of team and social competences in blended learning courses. Planning and modelling cooperative learning scenarios based on a domain specific modelling notation in the style of UML activity diagrams, and comparing evaluation results with planned outcomes allows for iterative optimization of a course's design. In a case study - a course on project management for computer science students - the instructional design including individual and cooperative learning situations was modelled. Specific emphasis was put on visualising the hypothesised development of team competences in the course design models. These models were subsequently compared to evaluation results obtained during the course. The results show that visual modelling of planned competence promotion enables more focused design, implementation and evaluation of collaborative learning scenarios

Exploring cognitive style and task-specific preferences for process representations

Process models describe someone's understanding of processes. Processes can be described using unstructured, semi-formal or diagrammatic representation forms. These representations are used in a variety of task settings, ranging from understanding processes to executing or improving processes, with the implicit assumption that the chosen representation form will be appropriate for all task settings. We explore the validity of this assumption by examining empirically the preference for different process representation forms depending on the task setting and cognitive style of the user. Based on data collected from 120 business school students, we show that preferences for process representation formats vary dependent on application purpose and cognitive styles of the participants. However, users consistently prefer diagrams over other representation formats. Our research informs a broader research agenda on task-specific applications of process modeling. We offer several recommendations for further research in this area

Regions of beta 2 and beta 4 responsible for differences between the steady state dose-response relationships of the alpha 3 beta 2 and alpha 3 beta 4 neuronal nicotinic receptors

We constructed chimeras of the rat beta 2 and beta 4 neuronal nicotinic subunits to locate the regions that contribute to differences between the acetylcholine (ACh) dose-response relationships of the alpha 3 beta 2 and alpha 3 beta 4 receptors. Expressed in Xenopus oocytes, the alpha 3 beta 2 receptor displays an EC50 for ACh approximately 20-fold less than the EC50 of the alpha 3 beta 4 receptor. The apparent Hill slope (n(app)) of alpha 3 beta 2 is near one whereas the alpha 3 beta 4 receptor displays an n(app) near two. Substitutions within the first 120 residues convert the EC50 for ACh from one wild-type value to the other. Exchanging just beta 2:104-120 for the corresponding region of beta 4 shifts the EC50 of ACh dose-response relationship in the expected direction but does not completely convert the EC50 of the dose- response relationship from one wild-type value to the other. However, substitutions in the beta 2:104-120 region do account for the relative sensitivity of the alpha 3 beta 2 receptor to cytisine, tetramethylammonium, and ACh. The expression of beta 4-like (strong) cooperativity requires an extensive region of beta 4 (beta 4:1-301). Relatively short beta 2 substitutions (beta 2:104-120) can reduce cooperativity to beta 2-like values. The results suggest that amino acids within the first 120 residues of beta 2 and the corresponding region of beta 4 contribute to an agonist binding site that bridges the alpha and beta subunits in neuronal nicotinic receptors

Semiclassical limits to the linewidth of an atom laser

We investigate the linewidth of a quasi-continuous atom laser within a semiclassical framework. In the high flux regime, the lasing mode can exhibit a number of undesirable features such as density fluctuations. We show that the output therefore has a complicated structure that can be somewhat simplified using Raman outcoupling methods and energy-momentum selection rules. In the weak outcoupling limit, we find that the linewidth of an atom laser is instantaneously Fourier limited, but, due to the energy `chirp' associated with the draining of a condensate, the long-term linewidth of an atom laser is equivalent to the chemical potential of the condensate source. We show that correctly sweeping the outcoupling frequency can recover the Fourier-limited linewidth.Comment: 9 Figure

Approaching the Heisenberg limit in an atom laser

We present experimental and theoretical results showing the improved beam quality and reduced divergence of an atom laser produced by an optical Raman transition, compared to one produced by an rf transition. We show that Raman outcoupling can eliminate the diverging lens effect that the condensate has on the outcoupled atoms. This substantially improves the beam quality of the atom laser, and the improvement may be greater than a factor of 10 for experiments with tight trapping potentials. We show that Raman outcoupling can produce atom lasers whose quality is only limited by the wave function shape of the condensate that produces them, typically a factor of 1.3 above the Heisenberg limit