A probabilistic framework for traffic data quality

Regarding the assessment of traffic data in ITS, there is an increasing need for answers to the following questions: (i) What exactly is "traffic data quality"?, and, related to that, (ii) There are too many ways to define and to do things, and results of different researchers are inconsistent or not comparable. How can we overcome this situation? With that background, an important aim of the ongoing DLR-project I.MoVe is to develop a consistent understanding of traffic data quality, together with a unified framework for its assessment. To this end, a probabilistic framework for traffic data quality is provided in this paper. Real-world examples from I.MoVe demonstrate its application for the assessment of data sources like induction loops, stationary bluetooth sensors and floating car data (FCD). A first important point is to distinguish strictly between quality indices, quality requirements, and quality itself. While the present framework develops quality indices based on established quality criteria like accuracy, completeness, validity, and coverage, the usual understanding of quality is extended to a probabilistic view. This also addresses the problem of information retrieval in the presence of vagueness and uncertainty. The provided examples are making full use of the proposed framework, and also constitute interesting results for the practitioner by themselves. Examples include the assessment of induction loop count data, and assessing the temporal coverage of a stretch of road with stationary bluetooth data, or of the whole city of Berlin, Germany with FCD

New insights on the interfacial tension of electrochemical interfaces and the Lippmann equation

The Lippmann equation is considered as universal relationship between interfacial tension, double layer charge, and cell potential. Based on the framework of continuum thermo-electrodynamics we provide some crucial new insights to this relation. In a previous work we have derived a general thermodynamic consistent model for electrochemical interfaces, which showed a remarkable agreement to single crystal experimental data. Here we apply the model to a curved liquid metal electrode. If the electrode radius is large compared to the Debye length, we apply asymptotic analysis methods and obtain the Lippmann equation. We give precise definitions of the involved quantities and show that the interfacial tension of the Lippmann equation is composed of the surface tension of our general model, and contributions arising from the adjacent space charge layers. This finding is confirmed by a comparison of our model to experimental data of several mercury-electrolyte interfaces. We obtain qualitative and quantitative agreement in the 2V potential range for various salt concentrations. We also discuss the validity of our asymptotic model when the electrode curvature radius is comparable to the Debye length

50 Jahre D-Mark

Im Laufe des letzten halben Jahrhunderts ist die Deutsche Mark zu einem Symbol für Stabilität geworden. Was läßt sich aus ihrer Geschichte für ihren Nachfolger, den Euro, lernen? Welche Chancen und Risiken sind mit der Ablösung der D-Mark verbunden? Welche Voraussetzungen müssen für eine stabile Entwicklung des Euro erfüllt sein? --

How Healthcare Professionals Comprehend Process Models - An Empirical Eye Tracking Analysis

Digitization is advancing rapidly in many prevalently analogue domains such as healthcare. For the latter domain, the synergies with modern information technologies (IT)have become an integral part regarding communication and collaboration. For this reason, a comprehensible language is of importance in order to allow for a frictionless exchange of information between domain experts. The Business Process Model and Notation (BPMN) 2.0 represents a promising notation that may be applied as lingua franca. Although BPMN 2.0 is widespread and applied by experts in business and industry, little experience exists on how BPMN 2.0 is adopted in healthcare. In order to assess how BPMN 2.0 is deployed in healthcare, we conducted a preliminary eye tracking study, in which n = 16 professionals from healthcare comprehended a particular BPMN 2.0 process model. The results indicate that BPMN 2.0 might be a candidate for a lingua franca to foster the comprehensible exchange of information as well as collaboration between healthcare and I

Warum Facebook Spaß macht: Freudvolles Erleben in sozialen Netzwerkdiensten

1 EINLEITUNG Kaum eine Anwendung des Internet hat in den letzten Jahren eine ähnlich dynamische Entwicklung genommen wie soziale Netzwerkdienste. Insbesondere Facebook hat mit seinen etwa 955 Millionen Nutzern (Stand Juni 2012) eine beispiellose Diffusionsdynamik entfaltet. Nach Boyd und Ellison [BE08] sind soziale Netzwerkdienste durch drei wesentliche Funktionen gekennzeichnet. Sie erlauben ihren individuellen Nutzern: (1) die Einrichtung eines öffentlichen oder halb-öffentlichen Profils, (2) das Anlegen einer Liste anderer Nutzer zu denen eine Verbindung besteht und (3) das Visualisieren und Traversieren der eigenen Liste und der Listen anderer Benutzer. Daneben beinhalten die verschiedenen Netzwerkdienste inzwischen eine Reihe weiterer Funktionen. So hat sich um Facebook durch die Bereitstellung einer Programmierschnittstelle ein ganzes Ökosystem von Anwendungen, wie etwa Social Games oder Voting-Apps, entwickelt. [...

Utilizing the Capabilities Offered by Eye-Tracking to Foster Novices' Comprehension of Business Porcess Models

Business process models constitute fundamental artifacts for enterprise architectures as well as for the engineering of processes and information systems. However, less experienced stakeholders (i.e., novices) face a wide range of issues when trying to read and comprehend these models. In particular, process model comprehension not only requires knowledge on process modeling notations, but also skills to visually and correctly interpret the models. In this context, many unresolved issues concerning the factors hindering process model comprehension exist and, hence, the identification of these factors becomes crucial. Using eye-tracking as an instrument, this paper presents the results obtained of a study, in which we analyzed eye-movements of novices and experts, while comprehending process models expressed in terms of the Business Process Model and Notation (BPMN) 2.0. Further, recorded eye-movements are visualized as scan paths to analyze the applied comprehension strategies. We learned that experts comprehend process models more effectively than novices. In addition, we observed particular patterns for eye-movements (e.g., back-and-forth saccade jumps) as well as different strategies of novices and experts in comprehending process models

Experimental investigation of the effect of transpiration cooling on second mode instabilities in a hypersonic boundary layer

The influence of localized nitrogen transpiration on second mode instabilities in a hypersonic boundary layer is experimentally investigated. The study is conducted using a 7deg half-angle cone with a length of 1100 mm and small nose bluntness at 0deg angle of attack. Transpiration is realized through a porous Carbon/Carbon patch of 44×82 mm located near the expected boundary layer transition onset location. Transpiration mass flow rates in the range of 0.05–1% of the equivalent boundary layer edge mass flow rate were used. Experiments were conducted in the High Enthalpy Shock Tunnel Göttingen (HEG) at total enthalpies around 3 MJ/kg and unit Reynolds numbers in the range of 1.4e6 to 6.4e6 1/m. Measurements were conducted by means of coaxial thermocouples, Atomic Layer Thermopiles (ALTP), pressure transducers and high-speed schlieren. The present study shows that the most amplified second mode frequencies were shifted to lower values as nitrogen is transpired into the boundary layer. In some cases the instability amplitudes were found to be significantly reduced. The observed frequency reduction was verified to correlate with the change of the relative sonic line height in the boundary layer. The amplitude damping was observed to occur only until the most amplified frequencies were reduced to around 50% of their undisturbed values. When transpiration within this limit was performed shortly upstream of the natural boundary layer transition onset, a transition delay of approximately 17% could be observed

A Case of Linear Porokeratosis Superimposed on Disseminated Superficial Actinic Porokeratosis

We present a female patient with linear porokeratosis of her right arm since childhood. At the age of 67 years she additionally developed disseminated superficial actinic porokeratosis (DSAP) involving both lower legs. This uncommon coexistence of two different types of porokeratosis fulfils the clinical criteria of a type 2 segmental manifestation of an autosomal dominant skin disorder, being superimposed on the ordinary nonsegmental lesions and reflecting loss of heterozygosity that occurred at an early developmental stage. In DSAP molecular evidence of this concept is so far lacking, but such proof has already been provided in several other autosomal dominant skin disorders. Molecular analysis of cases of type 2 segmental involvement may help elucidate the genetic defect causing DSAP