Principles for an Implementation of a Complete CT Reconstruction Tool Chain for Arbitrary Sized Data Sets and Its GPU Optimization

This article describes the implementation of an efficient and fast in-house computed tomography (CT) reconstruction framework. The implementation principles of this cone-beam CT reconstruction tool chain are described here. The article mainly covers the core part of CT reconstruction, the filtered backprojection and its speed up on GPU hardware. Methods and implementations of tools for artifact reduction such as ring artifacts, beam hardening, algorithms for the center of rotation determination and tilted rotation axis correction are presented. The framework allows the reconstruction of CT images of arbitrary data size. Strategies on data splitting and GPU kernel optimization techniques applied for the backprojection process are illustrated by a few examples.

Hard and soft materials: Putting consistent van der Waals density functionals to work

We present the idea and illustrate potential benefits of having a tool chain of closely related regular, unscreened and screened hybrid exchange-correlation (XC) functionals, all within the consistent formulation of the van der Waals density functional (vdW-DF) method [JPCM 32, 393001 (2020)]. Use of this chain of nonempirical XC functionals allows us to map when the inclusion of truly nonlocal exchange and of truly nonlocal correlation is important. Here we begin the mapping by addressing hard and soft material challenges: magnetic elements, perovskites, and biomolecular problems. We also predict the structure and polarization for a ferroelectric polymer. To facilitate this work and future broader explorations, we present a stress formulation for spin vdW-DF and illustrate the use of a simple stability-modeling scheme. The modeling supplements DFT (with a specific XC functional) by asserting whether the finding of a soft mode (an imaginary-frequency vibrational mode, ubiquitous in perovskites and soft matter) implies an actual DFT-based prediction of a low-temperature transformation.

Performance Data Visualization of Linux Events on Multicores

Profiling tools are essential to understand the behavior of parallel applications and assist in the optimization process. However, tools such as Perf generate a large amount of data. This way, they require significant storage space, which also complicates reasoning about this large volume of data. Therefore, we propose VisPerf: a tool-chain and an interactive visualization dashboard for Perf data. The VisPerf tool-chain profiles the application and pre-processes the data, reducing the storage space required by about 50 times. Moreover, we used the visualization dashboard to quickly understand the performance of different events and visualize specific threads and functions of a real-world application.

Visualising personas as goal models to find security tensions

Purpose This paper aims to present a tool-supported approach for visualising personas as social goal models, which can subsequently be used to identify security tensions. Design/methodology/approach The authors devised an approach to partially automate the construction of social goal models from personas. The authors provide two examples of how this approach can identify previously hidden implicit vulnerabilities and validate ethical hazards faced by penetration testers and their safeguards. Findings Visualising personas as goal models makes it easier for stakeholders to see implications of their goals being satisfied or denied and designers to incorporate the creation and analysis of such models into the broader requirements engineering (RE) tool-chain. Originality/value The approach can be used with minimal changes to existing user experience and goal modelling approaches and security RE tools.

DEVELOPMENT METHOD FOR REQUIREMENT COLLECTIVES OF HYDROGEN REFUELLING STATIONS

In addition to the development and research of battery-driven vehicles, a high research effort in the field of hydrogen technology can currently be observed. Various research and strategy initiatives relating to hydrogen are being initiated and pursued with considerable commitment worldwide. A significant expansion of the hydrogen filling station network is also being sought in Germany. In the course of designing a hydrogen refuelling station, the paradigms of thermal management must be taken into account in addition to a large number of different environmental and life phase-induced influencing factors. The interactions between influencing factors, requirements and the system architecture result in a multitude of possible refuelling station concepts, which can hardly be surveyed or managed from an organisational point of view. This publication introduces a method for the development of descriptive requirement collectives, which is applied to hydrogen refuelling stations in the framework of THEWA, but can also be adapted for other technical systems. The requirement collective is the first core element of the THEWA tool chain that enables a requirement-oriented and fast design of hydrogen refuelling stations.