Evaluation of ultrasound sensors for transcranial photoacoustic sensing and imaging

Biomedical photoacoustic (PA) imaging is typically used to exploit absorption-based contrast in soft tissue at depths of several centimeters. When it is applied to measuring PA waves generated in the brain, the acoustic properties of the skull bone cause not only strong attenuation but also a distortion of the wavefront, which diminishes image resolution and contrast. This effect is directly proportional to bone thickness. As a result, transcranial PA imaging in humans has been challenging to demonstrate. We measured the acoustic constraints imposed by the human skull to design an ultrasound sensor suitable for transcranial PA imaging and sensing. We imaged the phantoms using a planar Fabry-Perot sensor and employed a range of piezoelectric and optical ultrasound sensors to measure the frequency dependent acoustic transmission through human cranial bone. Transcranial PA images show typical frequency and thickness dependent attenuation and aberration effects associated with acoustic propagation through bone. The skull insertion loss measurements showed significant transmission at low frequencies. In comparison to conventional piezoelectric sensors, the performance of plano-concave optical resonator (PCOR) ultrasound sensors was found to be highly suitable for transcranial PA measurements. They possess high acoustic sensitivity at a low acoustic frequency range that coincides with the transmission window of human skull bone. PCOR sensors showed low noise equivalent pressures and flat frequency response which enabled them to outperform conventional piezoelectric transducers in transcranial PA sensing experiments. Transcranial PA sensing and imaging requires ultrasound sensors with high sensitivity at low acoustic frequencies, and a broad and ideally uniform frequency response. We designed and fabricated PCOR sensors and demonstrated their suitability for transcranial PA sensing

Fake News Perception in Germany: A Representative Study of People’s Attitudes and Approaches to Counteract Disinformation

Fake news has become an important topic in our social and political environment. While research is coming up for the U.S. and European countries, many aspects remain uncovered as long as existing work only marginally investigates people’s attitudes towards fake news. In this work, we present the results of a representative study (N=1023) in Germany asking participants about their attitudes towards fake news and approaches to counteract disinformation. More than 80% of the participants agree that fake news poses a threat. 78% see fake news as harming democracy. Even though about half of the respondents (48%) have noticed fake news, most participants stated to have never liked, shared or commented on fake news. Regarding demographic factors, our findings support the view of younger and relatively educated people being more informed about fake news. Concerning ideological motives, the evaluation suggests left-wing or liberal respondents to be more critical of fake news

Graphing Meeting Records - An Approach to Visualize Information in a Multi Meeting Context

Purpose – Meeting notes are effective records for participants and a source of information for members who were unable to attend. They act as a reference point to decisions made, to plan next steps, and to identify and track action items. Despite the need for a multi meeting solution (Tucker and Whittaker, 05), meetings are often displayed as separated as well as descriptive documents. The aim of this work is to enhance access to overlapping meeting contents and existing coherences beyond a decoupled description. A visual representation of meeting content can lead to meeting records which are more comprehensible and more time efficient. Furthermore, it enables the depiction of knowledge that is often lost in conventional meeting records. Approach – Our goal was to define a general structure for meeting items, integrating content categories and relations between successive meetings. In this paper, we present a model based approach to visualize meeting content as well as content relations in order to support the preparation, execution and follow-up of meetings. Due to the fact that contents of consecutive meetings refer to each other (Post et al., 04), we consider meetings as a series of events. The resulting model substantiates the transformation of content as well as content relations into a visual form. Value – The proposed solution focuses on the model that is integrated into an interactive visualization. Thus, a novel approach to explore meeting records is provided. The model was proved to be suitable for meeting contents in various use cases. Examining the content in its visual representation across multiple consecutive meetings enhances the identification of any linked information at a glance over even long periods of time. Hence, important pieces of information will not be disregarded. Practical implications – The approach of our multi meeting protocol application is realized as a browser-based implementation that displays data from JSON objects. With this interactive visualization, the user can browse, search, and filter meeting content and get a deeper understanding of topics, their life cycle and relations to other topics. This leads to an overall comprehension of project or business progression that highlights topics that need to be addressed. Thus, the viewer is supported in preparing, executing, and following up meetings successfully and qualified to structure records in order to keep a clean transcript of a meeting

Liveness-Driven Random Program Generation

Randomly generated programs are popular for testing compilers and program analysis tools, with hundreds of bugs in real-world C compilers found by random testing. However, existing random program generators may generate large amounts of dead code (computations whose result is never used). This leaves relatively little code to exercise a target compiler's more complex optimizations. To address this shortcoming, we introduce liveness-driven random program generation. In this approach the random program is constructed bottom-up, guided by a simultaneous structural data-flow analysis to ensure that the generator never generates dead code. The algorithm is implemented as a plugin for the Frama-C framework. We evaluate it in comparison to Csmith, the standard random C program generator. Our tool generates programs that compile to more machine code with a more complex instruction mix.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

Fake News Perception in Germany: A Representative Study of People's Attitudes and Approaches to Counteract Disinformation

Fake news has become an important topic in our social and political environment. While research is coming up for the U.S. and European countries, many aspects remain uncovered as long as existing work only marginally investigates people’s attitudes towards fake news. In this work, we present the results of a representative study (N=1023) in Germany asking participants about their attitudes towards fake news and approaches to counteract disinformation. More than 80% of the participants agree that fake news poses a threat. 78% see fake news as harming democracy. Even though about half of the respondents (48%) have noticed fake news, most participants stated to have never liked, shared or commented on fake news. Regarding demographic factors, our findings support the view of younger and relatively educated people being more informed about fake news. Concerning ideological motives, the evaluation suggests left-wing or liberal respondents to be more critical of fake news