Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Enhancing Real-Time Twitter Filtering and Classification using a Semi-Automatic Dynamic Machine Learning setup approach

Twitter contains massive amounts of user generated content that also contains a lot of valuable information for various interested parties. Twitcident has been developed to process and filter this information in real-time for interested parties by monitoring a set of predefined topics, exploiting humans as sensors. An analysis of the relevant information by an operator can result in an estimation of severity, and an operator can act accordingly. However, among all relevant and useful content that is extracted, also a lot of irrelevant noise is present. Our goal is to improve the filter in such a way that the majority of information presented by Twitcident is relevant. To this end we designed an artifact consisting of several components, developed within a dynamic framework. Its major components include a machine learning classifier operating on dynamic features, a semi-automatic setup approach and a training approach. Our prototype operates on Dutch content, but it can be adapted to operate on any language. With a partially implemented prototype of our designed artifact we achieve F2-scores of 0.7 up to 0.9 for our Dutch test-sets using 10-fold cross validation, which is on average a 30% improvement over the existing Twitcident filtering architecture. The artifact is robustly designed, allowing for many forms of future improvements and extensions. We also make some side-contributions, like an approximate matching algorithm for variable length strings.Web Information SystemsSoftware TechnologyElectrical Engineering, Mathematics and Computer Scienc

BSc-project: Eindverslag, VCN-Web: TCTeamTool & Takenbeheer

Voor dit project, ter afronding van de bacheloropleiding Technische Informatica van de Technische Universiteit Delft, zijn een aantal componenten voor VCN-Web ontwikkeld; nadat een eerder project om medische redenen was afgebroken. Het VCN-Web systeem omvat een publieke gebruikerssite met veel dynamische informatie en voorzieningen, en vernieuwend op vele gebieden. Het betreft een pseudo zelf-regulerend systeem dat een kernorgaan van de volleybalvereniging VCN vormt. Achter het VCN-Web systeem steekt een uitgebreid framework met vele mogelijkheden en voorzieningen, waar de ontwikkelde componenten in geïntegreerd zijn. De 2 hoofdcomponenten, de TCTeamTool en het Takenbeheer, zijn in opdracht van Sharpener voor respectievelijk de TC’s en de Takenbeheerder als eindgebruikers ontwikkelt. Kortweg kan er gesteld worden dat de functies van de TC’s en takenbeheerder ‘gedigitaliseerd’ en ‘geintegreerd’ moesten worden binnen het VCN-Web systeem. De TCTeamTool is een component om intern de teamindelingen mee op te kunnen zetten, en deze te kunnen publiceren op de website voor ingelogde leden. Tevens kunnen de TC’s hiermee de informatie op de website waar zij verantwoordelijk voor zijn bewerken. Met het takenbeheer kan de takenbeheerder efficiënt de taken voor wedstrijden inroosteren en publiceren op de website, waarbij zij altijd beschikt over de meest actuele en relevante informatie. Omdat veel van de wensen rondom het takenbeheer de actuele en automatische verwerking van wedstrijden omvat, is ook hiervoor een component ontwikkeld. Dit was in eerste instantie niet de bedoeling, maar is voor de volledigheid toch gedurende de projectperiode binnen het kader van dit project ontwikkeld.Software TechnologyElectrical Engineering, Mathematics and Computer Scienc

A Culture-Inspired Approach to Gaining Insights for Designing Sustainable Practices

This paper explores a design method to generate insights for designing less resource-intensive forms of everyday life. This study takes the assumption that looking at cultural diversity can widen the variety of insights which can be used as a source of inspiration for designing sustainable practices. However, there is a lack of clear-cut approaches for collecting information on sustainable everyday practices from multiple cultures. Therefore, this study explores: 1) how to collect information about resource-consuming everyday practice from different cultures, and 2) what kinds of insights can be gained from this information. An experimental culture survey was conducted. The survey had the practice ‘bathing’ as the central topic, and featured three countries; the Netherlands, Japan and India. The results suggest that a self-observation probe with a feature of recording the practice by a set of elements was successful in collecting information from users in three countries. From this information, three types of insights were generated, which are expected to be useful in the context of designing sustainable practices. These are: 1) different styles of bathing and their respective resource consumption, 2) relations between the contextual elements and 3) particular actions which have a considerable impact on the total resource consumption.Industrial DesignIndustrial Design Engineerin

Strategic Use of Analytical Information in Transport Planning in China: How Is It Different from Western Democracies?

Theory on the strategic use of knowledge in planning large infrastructure projects is comparatively well-developed in the fields of public policy and urban/transport planning for Western democracies. But how policymakers make use of knowledge and what position policy analysts hold in non-Western countries still remains largely unknown territory in the literature. This article begins to explore this topic by studying two urban transport projects in the Chinese city of Dalian. Based on empirical evidence, the article concludes with a number of preliminary but notable differences between Western countries and China in terms of the administrative mechanisms underlying the strategic use of knowledge in policymaking. We found that Chinese institutional incentives with regard to cadre evaluation and promotion channels largely constitute the motivation of politicians to use knowledge strategically. Additionally, the wider social and administrative cultures in China, including a command-and-control tradition and a high level of power distance create a basis for the strategic use of information as well as the manipulation of analytical data.Accepted Author ManuscriptTransport and LogisticsOrganisation and Governanc

Comparison of Phase-Screen and Geometry-Based Phase Aberration Correction Techniques for Real-Time Transcranial Ultrasound Imaging

While transcranial ultrasound imaging is a promising diagnostic modality, it is still hindered due to phase aberration and multiple scattering caused by the skull. In this paper, we compare near-field phase-screen modeling (PS) to a geometry-based phase aberration correction technique (GB) when an ultrafast imaging sequence (five plane waves tilted from −15 to +15 degrees in the cutaneous tissue layer) is used for data acquisition. With simulation data, the aberration profile (AP) of two aberrator models (flat and realistic temporal bone) was estimated in five isoplanatic patches, while the wave-speed of the brain tissue surrounding the point targets was either modeled homogeneously (ideal) or slightly heterogeneously to generate speckle (for mimicking a more realistic brain tissue). For the experiment, a phased array P4-1 transducer was used to image a wire phantom; a 4.2-mm-thick bone-mimicking plate was placed in front of the probe. The AP of the plate was estimated in three isoplanatic patches. The numerical results indicate that, while all the scatterers are detectable in the image reconstructed by the GB method, many scatterers are not detected with the PS method when the dataset used for AP estimation is generated with a realistic bone model and heterogeneous brain tissue. The experimental results show that the GB method increases the signal-to-clutter ratio (SCR) by 7.5 dB and 6.5 dB compared to the PS and conventional reconstruction methods, respectively. The GB method reduces the axial/lateral localization error by 1.97/0.66 mm and 2.08/0.7 mm compared to the PS method and conventional reconstruction, respectively. The lateral spatial resolution (full-width-half-maximum) is also improved by 0.1 mm and 1.06 mm compared to the PS method and conventional reconstruction, respectively. Our comparison study suggests that GB aberration correction outperforms the PS method when an ultrafast multi-angle plane wave sequence is used for transcranial imaging with a single transducer.ImPhys/Medical Imagin

Accelerated 2D Real-Time Refraction-Corrected Transcranial Ultrasound Imaging

In a recent study, we proposed a technique to correct aberration caused by the skull and reconstruct a transcranial B-mode image with a refraction-corrected synthetic aperture imaging (SAI) scheme. Given a sound speed map, the arrival times were calculated using a fast marching technique (FMT), which solves the Eikonal equation and, therefore, is computationally expensive for real-time imaging. In this article, we introduce a two-point ray tracing method, based on Fermat's principle, for fast calculation of the travel times in the presence of a layered aberrator in front of the ultrasound probe. The ray tracing method along with the reconstruction technique is implemented on a graphical processing unite (GPU). The point spread function (PSF) in a wire phantom image reconstructed with the FMT and the GPU implementation was studied with numerical synthetic data and experiments with a bone-mimicking plate and a sagittally cut human skull. The numerical analysis showed that the error on travel times is less than 10% of the ultrasound temporal period at 2.5 MHz. As a result, the lateral resolution was not significantly degraded compared with images reconstructed with FMT-calculated travel times. The results using the synthetic, bone-mimicking plate, and skull dataset showed that the GPU implementation causes a lateral/axial localization error of 0.10/0.20, 0.15/0.13, and 0.26/0.32 mm compared with a reference measurement (no aberrator in front of the ultrasound probe), respectively. For an imaging depth of 70 mm, the proposed GPU implementation allows reconstructing 19 frames/s with full synthetic aperture (96 transmission events) and 32 frames/s with multiangle plane wave imaging schemes (with 11 steering angles) for a pixel size of $200~\mu \text{m}$. Finally, refraction-corrected power Doppler imaging is demonstrated with a string phantom and a bone-mimicking plate placed between the probe and the moving string. The proposed approach achieves a suitable frame rate for clinical scanning while maintaining the image quality.ImPhys/Medical ImagingImPhys/Computational Imagin

Single-crystal Pt-decorated WO₃ ultrathin films: a platform for sub-ppm hydrogen sensing at room temperature

Hydrogen-related technologies are rapidly developing, driven by the necessity of efficient and high-density energy storage. This poses new challenges to the detection of dangerous gases, in particular the realization of cheap, sensitive, and fast hydrogen sensors. Several materials are being studied for this application, but most present critical bottlenecks, such as high operational temperature, low sensitivity, slow response time, and/or complex fabrication procedures. Here, we demonstrate that WO3 in the form of single-crystal, ultrathin films with a Pt catalyst allows high-performance sensing of H2 gas at room temperature. Thanks to the high electrical resistance in the pristine state, this material is able to detect hydrogen concentrations down to 1 ppm near room temperature. Moreover, the high surface-to-volume ratio of WO3 ultrathin films determines fast sensor response and recovery, with characteristic times as low as 1 s when the concentration exceeds 100 ppm. By modeling the hydrogen (de)intercalation dynamics with a kinetic model, we extract the energy barriers of the relevant processes and relate the doping mechanism to the formation of oxygen vacancies. Our results reveal the potential of single-crystal WO3 ultrathQN/Caviglia LabApplied Science

Fundamental modeling of wave propagation in temporally relaxing media with applications to cardiac shear wave elastography

Shear wave elastography (SWE) might allow non-invasive assessment of cardiac stiffness by relating shear wave propagation speed to material properties. However, after aortic valve closure, when natural shear waves occur in the septal wall, the stiffness of the muscle decreases significantly, and the effects of such temporal variation of medium properties on shear wave propagation have not been investigated yet. The goal of this work is to fundamentally investigate these effects. To this aim, qualitative results were first obtained experimentally using a mechanical setup, and were then combined with quantitative results from finite difference simulations. The results show that the amplitude and period of the waves increase during propagation, proportional to the relaxation of the medium, and that reflected waves can originate from the temporal stiffness variation. These general results, applied to literature data on cardiac stiffness throughout the heart cycle, predict as a major effect a period increase of 20% in waves propagating during a healthy diastolic phase, whereas only a 10% increase would result from the impaired relaxation of an infarcted heart. Therefore, cardiac relaxation can affect the propagation of waves used for SWE measurements and might even provide direct information on the correct relaxation of a heart.ImPhys/Medical Imagin

Transcranial Ultrasound Imaging with Estimating the Geometry, Position and Wave-Speed of Temporal Bone

Transcranial ultrasound imaging is a suitable technology for diagnosis of strokes as it is safe, portable, relatively inexpensive and available in emergency medicine services, however it currently offers poor image quality due to the phase aberration caused by the human skull. In this work, we evaluate an approach for two-dimensional transcranial ultrasound imaging through the temporal window of a sagittally-cut human skull using the commercial P4-1 phased-array probe, where the position and true geometry of the bone layer is estimated for accurate phase aberration correction. The medium is described with four layers (probe lens, soft tissue, skull, soft tissue). A synthetic aperture imaging scheme is used as the transmission of spherical wave-fronts facilitates the modeling of refraction. First, the bidirectional headwave method estimates the compressional wave-speed in the temporal bone. Next, a fast marching method calculates the travel times between individual array elements and image pixels to be used with delay-and-sum reconstruction algorithm. Sound speed maps are generated with adaptive beamforming including the successive segmentation of the near and far surfaces of the cortical bone layer. The proposed method reconstructs the scatterers with an average lateral and axial localization error of about 1.25 mm and 0.37 mm, compared to the ground truth, respectively. In average, it improves the contrast ratio and lateral resolution by 7 dB and 36%, compared to the conventional method, respectively.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ImPhys/Medical Imagin