scholarly journals A Tomograph Prototype for Quantitative Microwave Imaging: Preliminary Experimental Results

2018 ◽  
Vol 4 (12) ◽  
pp. 139 ◽  
Author(s):  
Alessandro Fedeli ◽  
Manuela Maffongelli ◽  
Ricardo Monleone ◽  
Claudio Pagnamenta ◽  
Matteo Pastorino ◽  
...  
Keyword(s):  
Ad Hoc ◽  
Microwave Imaging ◽  
Experimental Results ◽  
Network Analyzer ◽  
Reconstruction Algorithms ◽  
Quantitative Reconstruction ◽  
Qualitative And Quantitative ◽  
Switching Matrix ◽  
3D Printed ◽  
Transmission Measurements

A new prototype of a tomographic system for microwave imaging is presented in this paper. The target being tested is surrounded by an ad-hoc 3D-printed structure, which supports sixteen custom antenna elements. The transmission measurements between each pair of antennas are acquired through a vector network analyzer connected to a modular switching matrix. The collected data are inverted by a hybrid nonlinear procedure combining qualitative and quantitative reconstruction algorithms. Preliminary experimental results, showing the capabilities of the developed system, are reported.

scholarly journals Production, Validation and Morphometric Analysis of a Digital Terrain Model for Lake Trichonis Using Geospatial Technologies and Hydroacoustics

2021 ◽  
Vol 10 (2) ◽  
pp. 91
Author(s):  
Triantafyllia-Maria Perivolioti ◽  
Antonios Mouratidis ◽  
Dimitrios Terzopoulos ◽  
Panagiotis Kalaitzis ◽  
Dimitrios Ampatzidis ◽  
...  
Keyword(s):  
Morphometric Analysis ◽  
Ad Hoc ◽  
Regional Scale ◽  
Digital Terrain Model ◽  
Relevant Information ◽  
Relative Difference ◽  
Systematic Observation ◽  
Qualitative And Quantitative ◽  
Terrain Model ◽  
Digital Terrain

Covering an area of approximately 97 km2 and with a maximum depth of 58 m, Lake Trichonis is the largest and one of the deepest natural lakes in Greece. As such, it constitutes an important ecosystem and freshwater reserve at the regional scale, whose qualitative and quantitative properties ought to be monitored. Depth is a crucial parameter, as it is involved in both qualitative and quantitative monitoring aspects. Thus, the availability of a bathymetric model and a reliable DTM (Digital Terrain Model) of such an inland water body is imperative for almost any systematic observation scenario or ad hoc measurement endeavor. In this context, the purpose of this study is to produce a DTM from the only official cartographic source of relevant information available (dating back approximately 70 years) and evaluate its performance against new, independent, high-accuracy hydroacoustic recordings. The validation procedure involves the use of echosoundings coupled with GPS, and is followed by the production of a bathymetric model for the assessment of the discrepancies between the DTM and the measurements, along with the relevant morphometric analysis. Both the production and validation of the DTM are conducted in a GIS environment. The results indicate substantial discrepancies between the old DTM and contemporary acoustic data. A significant overall deviation of 3.39 ± 5.26 m in absolute bottom elevation differences and 0.00 ± 7.26 m in relative difference residuals (0.00 ± 2.11 m after 2nd polynomial model corrector surface fit) of the 2019 bathymetric dataset with respect to the ~1950 lake DTM and overall morphometry appear to be associated with a combination of tectonics, subsidence and karstic phenomena in the area. These observations could prove useful for the tectonics, geodynamics and seismicity with respect to the broader Corinth Rift region, as well as for environmental management and technical interventions in and around the lake. This dictates the necessity for new, extensive bathymetric measurements in order to produce an updated DTM of Lake Trichonis, reflecting current conditions and tailored to contemporary accuracy standards and state-of-the-art research in various disciplines in and around the lake.

scholarly journals Manual kidney stone size measurements in computed tomography are most accurate using multiplanar image reformatations and bone window settings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Robert Peter Reimer ◽  
Konstantin Klein ◽  
Miriam Rinneburger ◽  
David Zopfs ◽  
Simon Lennartz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Treatment Decision ◽  
Reconstruction Algorithm ◽  
Slice Thickness ◽  
Reconstruction Algorithms ◽  
Stone Size ◽  
Bone Window ◽  
3D Printed ◽  
Measurement Strategies ◽  
Digital Caliper

AbstractComputed tomography in suspected urolithiasis provides information about the presence, location and size of stones. Particularly stone size is a key parameter in treatment decision; however, data on impact of reformatation and measurement strategies is sparse. This study aimed to investigate the influence of different image reformatations, slice thicknesses and window settings on stone size measurements. Reference stone sizes of 47 kidney stones representative for clinically encountered compositions were measured manually using a digital caliper (Man-M). Afterwards stones were placed in a 3D-printed, semi-anthropomorphic phantom, and scanned using a low dose protocol (CTDIvol 2 mGy). Images were reconstructed using hybrid-iterative and model-based iterative reconstruction algorithms (HIR, MBIR) with different slice thicknesses. Two independent readers measured largest stone diameter on axial (2 mm and 5 mm) and multiplanar reformatations (based upon 0.67 mm reconstructions) using different window settings (soft-tissue and bone). Statistics were conducted using ANOVA ± correction for multiple comparisons. Overall stone size in CT was underestimated compared to Man-M (8.8 ± 2.9 vs. 7.7 ± 2.7 mm, p < 0.05), yet closely correlated (r = 0.70). Reconstruction algorithm and slice thickness did not significantly impact measurements (p > 0.05), while image reformatations and window settings did (p < 0.05). CT measurements using multiplanar reformatation with a bone window setting showed closest agreement with Man-M (8.7 ± 3.1 vs. 8.8 ± 2.9 mm, p < 0.05, r = 0.83). Manual CT-based stone size measurements are most accurate using multiplanar image reformatation with a bone window setting, while measurements on axial planes with different slice thicknesses underestimate true stone size. Therefore, this procedure is recommended when impacting treatment decision.

Experimental performance of optimized trusses

2021 ◽  
Author(s):  
Joshua A. Schultz ◽  
Phillip Geist ◽  
Brooke Whitsell ◽  
Rachel Dorr
Keyword(s):  
Point Load ◽  
Experimental Results ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Experimental Performance ◽  
High Rise ◽  
Truss Topology ◽  
Failure Loads ◽  
3D Printed

<p>A series of six 3D printed discretely optimized truss specimens and two warren truss specimens were experimentally loaded until failure. The results were compared to the theoretical failure loads and stresses determined using Maxwell’s Method. Each set of truss specimens were loaded in a simple span condition, with a point load applied at the center of the span. Each truss specimen was configured into pairs in order to prevent lateral torsional buckling (LTB) while testing. Strain, load, and displacement data was gathered for each truss specimen tested. These results were compared to the predicted results calculated by Maxwell’s theorem. Of the 6 specimens tested, all of the trusses failed within 1% - 20% of the analytical vales. The trends in the experimental results support efficacy of previously developed theories of optimized truss topology in order to increase strength and efficiency of lateral systems in high rise structures.</p>

scholarly journals How to Validate in silico Deployment of Coronary Stents: Strategies and Limitations in the Choice of Comparator

2021 ◽  
Vol 3 ◽  
Author(s):  
Francesca Berti ◽  
Luca Antonini ◽  
Gianluca Poletti ◽  
Constantino Fiuza ◽  
Ted J. Vaughan ◽  
...  
Keyword(s):  
Numerical Model ◽  
Medical Devices ◽  
In Silico ◽  
Computational Models ◽  
Ad Hoc ◽  
Coronary Stent ◽  
Controlled Environment ◽  
Stent Deployment ◽  
Validation Plan ◽  
3D Printed

This study aims at proposing and discussing useful indications to all those who need to validate a numerical model of coronary stent deployment. The proof of the reliability of a numerical model is becoming of paramount importance in the era of in silico trials. Recently, the ASME V&amp;V Standard Committee for medical devices prepared the V&amp;V 40 standard document that provides a framework that guides users in establishing and assessing the relevance and adequacy of verification and validation activities performed for proving the credibility of models. To the knowledge of the authors, only a few examples of the application of the V&amp;V 40 framework to medical devices are available in the literature, but none about stents. Specifically, in this study, the authors wish to emphasize the choice of a relevant set of experimental activities to provide data for the validation of computational models aiming to predict coronary stent deployment. Attention is focused on the use of ad hoc 3D-printed mock vessels in the validation plan, which could allow evaluating aspects of clinical relevance in a representative but controlled environment.

How to Engineer Gamification

2019 ◽  
Vol 31 (1) ◽  
pp. 39-60 ◽  
Author(s):  
Alimohammad Shahri ◽  
Mahmood Hosseini ◽  
Keith Phalp ◽  
Jacqui Taylor ◽  
Raian Ali
Keyword(s):  
Development Process ◽  
Ad Hoc ◽  
Good Practice ◽  
Good Deal ◽  
Business Context ◽  
Qualitative And Quantitative ◽  
Strategic Objective ◽  
Body Of Knowledge ◽  
Two Phases ◽  
Game Elements

Gamification refers to the use of game elements in a business context to change users' behaviours, mainly increasing motivation towards a certain task or a strategic objective. Gamification has received a good deal of emphasis in both academia and industry across various disciplines and application areas. Despite the increasing interest, we still need a unified and holistic picture on how to engineer gamification, including the meaning of the term, its development process, the stakeholders and disciplines which need to be involved in it, and the concerns and risks that an ad-hoc design could raise for both businesses and users. To address this need, this article reports on empirical research which involved reviewing the literature and a range of gamification techniques and applications as secondary research, and an expert opinion study of two phases, qualitative and quantitative, as primary research. Based on the results, we provide a body of knowledge about gamification and point-out good practice principles and areas of gamification that are debatable and need further investigation.

Modeling of High-Signal Electrostriction. II

1990 ◽  
Vol 45 (9-10) ◽  
pp. 1095-1101
Author(s):  
J von Cieminski
Keyword(s):  
Phase Transition ◽  
Temperature Dependence ◽  
Strain Field ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Second Order ◽  
Experimental Results ◽  
High Signal ◽  
Qualitative And Quantitative

Abstract The predictions obtained with a thermodynamical method are compared with experimental results. Several materials which pass a ferroelectric phase transition of first or second order are investigated. The predictions correspond well with the experimentaly determined qualitative and quantitative features as to the field and temperature dependence. Finally, extraordinary strain-field curves are predicted and proved.

scholarly journals Wearable Augmented Reality Platform for Aiding Complex 3D Trajectory Tracing

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1612 ◽  
Author(s):  
Sara Condino ◽  
Benish Fida ◽  
Marina Carbone ◽  
Laura Cercenelli ◽  
Giovanni Badiali ◽  
...  
Keyword(s):  
Augmented Reality ◽  
High Precision ◽  
Ad Hoc ◽  
User Study ◽  
Peripersonal Space ◽  
Planar Structures ◽  
3D Printed ◽  
Quantitative Results ◽  
Manual Tasks ◽  
Wearable Augmented Reality

Augmented reality (AR) Head-Mounted Displays (HMDs) are emerging as the most efficient output medium to support manual tasks performed under direct vision. Despite that, technological and human-factor limitations still hinder their routine use for aiding high-precision manual tasks in the peripersonal space. To overcome such limitations, in this work, we show the results of a user study aimed to validate qualitatively and quantitatively a recently developed AR platform specifically conceived for guiding complex 3D trajectory tracing tasks. The AR platform comprises a new-concept AR video see-through (VST) HMD and a dedicated software framework for the effective deployment of the AR application. In the experiments, the subjects were asked to perform 3D trajectory tracing tasks on 3D-printed replica of planar structures or more elaborated bony anatomies. The accuracy of the trajectories traced by the subjects was evaluated by using templates designed ad hoc to match the surface of the phantoms. The quantitative results suggest that the AR platform could be used to guide high-precision tasks: on average more than 94% of the traced trajectories stayed within an error margin lower than 1 mm. The results confirm that the proposed AR platform will boost the profitable adoption of AR HMDs to guide high precision manual tasks in the peripersonal space.

Sign in / Sign up

Export Citation Format

Share Document