Filtern
Erscheinungsjahr
- 2017 (124)
- 2018 (84)
- 2022 (78)
- 2016 (70)
- 2021 (67)
- 2020 (60)
- 2015 (59)
- 2019 (55)
- 2023 (49)
- 2013 (45)
- 2006 (39)
- 2014 (35)
- 2007 (33)
- 2010 (32)
- 2008 (31)
- 2012 (31)
- 2005 (28)
- 2011 (27)
- 2003 (23)
- 2002 (20)
- 2001 (19)
- 2004 (19)
- 2009 (18)
- 2000 (16)
- 1996 (9)
- 1999 (9)
- 2024 (9)
- 1998 (7)
- 1995 (6)
- 1997 (4)
- 1994 (2)
- 1983 (1)
- 1987 (1)
- 1988 (1)
- 1992 (1)
Dokumenttyp
- Wissenschaftlicher Artikel (1112) (entfernen)
Sprache
- Deutsch (872)
- Englisch (237)
- Französisch (2)
- Spanisch (1)
Schlagworte
- Geldpolitik (6)
- Arbeitsrecht (4)
- Building Information Modeling (4)
- Deutschland (4)
- Energiepolitik (4)
- Kühllastberechnung (4)
- E-Learning (3)
- Europäische Union (3)
- Europäische Zentralbank (3)
- GmbH (3)
Institut
- Wirtschaftsrecht (448)
- Institut für Internetsicherheit (160)
- Wirtschaft und Informationstechnik Bocholt (68)
- Institut für Innovationsforschung und -management (55)
- Westfälisches Energieinstitut (55)
- Westfälisches Institut für Gesundheit (47)
- Wirtschaft Gelsenkirchen (36)
- Elektrotechnik und angewandte Naturwissenschaften (33)
- Informatik und Kommunikation (32)
- Wirtschaftsingenieurwesen (25)
We report on investigations that illustrate the interaction between the specific immune system and a young avascular tumor growing due to a diffusive nutrient supply. We formulate a hybrid cellular automata-partial differential equation (CA-PDE) model which includes cell cycle dynamics and allows for tracking the spatial and temporal evolution of this elaborate biological system. We present results of two dimensional numerical simulations that, specifically in this work, include special cases of the spherical and papillary tumor growth, the infiltration of immune system cells into the tumor and the escape of tumor cells from the regime of the immune cells.
Stereotactic frame systems are widely used in neurosurgery. The accuracy of frame devices is considered as a gold standard to which the accuracy of new frameless stereotactic navigation systems is compared. The purpose of this study is to develop a general approach for the prediction of the application accuracy of stereotactic systems. The approach will be applied to the frame‐based biopsy performed with three frame devices: Leksell G, Cosman–Roberts–Wells (CRW), and Brown–Roberts–Wells (BRW). A work‐flow analysis will be carried out demonstrating that the accuracy relevant for a clinical application comprises several error sources including imaging, target and entry point selection, image to frame coordinates registration, and the setting of mechanical parameters of the frame. These error sources will be postulated to obey a Gaussian distribution probability density. The linear, i.e., Gaussian, error propagation, will be used to link all error contributions thus to calculate the cumulative accuracy of the frame used in the application. Although the Gaussian approach is an approximation, it allows for an analytical treatment of the accuracy. Both the accuracy at the target point and the accuracy of the probe needle guidance along the planned trajectory have been investigated. Of great significance is the relationship found between accuracy, pixel dimension, and image slice thickness, the latter being the dominant factor for slices of more than 1.5 mm thickness, yielding inaccuracies larger than 1.5 mm. For target points the predictions for the application accuracy have been compared to the results of measurements, showing good agreement with the experimental data.
A qualitative work‐flow analysis of a neurosurgical procedure indicates that the resolution of the image used to plan the intervention is the major source of inaccuracy. Quantitative experimental measurements confirm this observation. They fail, however, to explain the relationship between the accuracy of the frame components involved in a stereotactic procedure and the overall application accuracy. This investigation shows that the novel Gaussian approach is a flexible framework for the calculation of the application accuracy of frame systems. Therefore, the Gaussian approach provides a detailed understanding of the interplay between the various factors affecting accuracy. The basic ideas and limitations of the Gaussian approach are briefly explained. The effect of fiducial marker distribution and registration is investigated and shown to introduce a spatial dependence to the accuracy. The results of the Gaussian approach are compared with experimental data for three stereotactic frame devices: Leksell G, Cosman–Roberts–Wells, and Brown–Roberts–Wells. Although the Gaussian approach is an approximation, it reproduces the accuracy measured in the experiment within the statistical error of that experiment. Comp Aid Surg 4:77–86 (1999). © 1999 Wiley‐Liss, Inc.
The set of transactions that occurs on the public ledger of an Ethereum network in a specific time frame can be represented as a directed graph, with vertices representing addresses and an edge indicating the interaction between two addresses.
While there exists preliminary research on analyzing an Ethereum network by the means of graph analysis, most existing work is focused on either the public Ethereum Mainnet or on analyzing the different semantic transaction layers using static graph analysis in order to carve out the different network properties (such as interconnectivity, degrees of centrality, etc.) needed to characterize a blockchain network. By analyzing the consortium-run bloxberg Proof-of-Authority (PoA) Ethereum network, we show that we can identify suspicious and potentially malicious behaviour of network participants by employing statistical graph analysis. We thereby show that it is possible to identify the potentially malicious
exploitation of an unmetered and weakly secured blockchain network resource. In addition, we show that Temporal Network Analysis is a promising technique to identify the occurrence of anomalies in a PoA Ethereum network.
With ongoing developments in the field of smart cities and digitalization in general, data is becoming a driving factor and value stream for new and existing economies alike. However, there exists an increasing centralization and monopolization of data holders and service providers, especially in the form of the big US-based technology companies in the western world and central technology providers with close ties to the government in the Asian regions. Self Sovereign Identity (SSI) provides the technical building blocks to create decentralized data-driven systems, which bring data autonomy back to the users. In this paper we propose a system in which the combination of SSI and token economy based incentivisation strategies makes it possible to unlock the potential value of data-pools without compromising the data autonomy of the users.
Proof of Existence as a blockchain service has first been published in 2013 as a public notary service on the Bitcoin network and can be used to verify the existence of a particular file in a specific point of time without sharing the file or its content itself. This service is also available on the Ethereum based bloxberg network, a decentralized research infrastructure that is governed, operated and developed by an international consortium of research facilities. Since it is desirable to integrate the creation of this proof tightly into the research workflow, namely the acquisition and processing of research data, we show a simple to integrate MATLAB extension based solution with the concept being applicable to other programming languages and environments as well.