3,066 research outputs found
A posteriori modeling error estimates in the optimization of two-scale elastic composite materials
The a posteriori analysis of the discretization error and the modeling error
is studied for a compliance cost functional in the context of the optimization
of composite elastic materials and a two-scale linearized elasticity model. A
mechanically simple, parametrized microscopic supporting structure is chosen
and the parameters describing the structure are determined minimizing the
compliance objective. An a posteriori error estimate is derived which includes
the modeling error caused by the replacement of a nested laminate
microstructure by this considerably simpler microstructure. Indeed, nested
laminates are known to realize the minimal compliance and provide a benchmark
for the quality of the microstructures. To estimate the local difference in the
compliance functional the dual weighted residual approach is used. Different
numerical experiments show that the resulting adaptive scheme leads to simple
parametrized microscopic supporting structures that can compete with the
optimal nested laminate construction. The derived a posteriori error indicators
allow to verify that the suggested simplified microstructures achieve the
optimal value of the compliance up to a few percent. Furthermore, it is shown
how discretization error and modeling error can be balanced by choosing an
optimal level of grid refinement. Our two scale results with a single scale
microstructure can provide guidance towards the design of a producible
macroscopic fine scale pattern
Analytically weak solutions to SPDEs with unbounded time-dependent differential operators and an application
We analyze the concepts of analytically weak solutions of stochastic
differential equations (SDEs) in Hilbert spaces with time-dependent unbounded
operators and give conditions for existence and uniqueness of such solutions.
Our studies are motivated by a stochastic partial differential equation (SPDE)
arising in industrial mathematics
Design and Evaluation of Domain-Specific Platforms and the Special Case of Digital Healthcare
The implementation of digital innovations in the healthcare sector is faced with different barriers and challenges. The complex system of regulations, the lack of interoperability, and highly dynamic interorganisational networks lead to missing widespread adoption of eHealth solutions. Digital platforms can help to overcome these barriers by providing a holistic infrastructure. They create a modularised foundation that innovators can use to create own innovations and provide them to demanders of digital solutions. As intermediaries, they can be accessed both by healthcare professionals and eHealth solution providers. Providers can offer their eHealth services via the platform. Healthcare professionals can use these services to create own interorganisational information systems.
In the field of information systems research, effects and strategies for two-sided platforms are well researched and the potentials of eHealth platforms are also discussed. However, the organisational and technological design and methods for the construction of platforms are fewer questioned. Nonetheless, platform owners can benefit from implementation strategies and architectural guidance to create sustainable platforms and surrounding ecosystems.
This doctoral thesis questions how domain-specific platforms can be designed systematically. Conducting a design-science research process, it develops both a modelling system and the Dresden Ecosystem Management Method (DREEM) to support the development of platforms in different domains. Furthermore, it describes the design characteristics of two-sided platforms in the healthcare sector and provides an evaluation approach to analyse the platforms’ ability to create a viable innovation ecosystem in the healthcare sector.
The doctoral thesis contributes by providing methodical guidance for platform owners and researchers to design and evaluate digital platforms in different domains and improves the understanding of platform theory in the healthcare sector.:A. Synopsis of the Doctoral Thesis
1. Introduction
2. Foundational Considerations
3. Requirements for Design Artefacts and Knowledge
4. Structure of the Doctoral Thesis
5. Conclusion
B. Paper 1 - Governance Guidelines for Digital Healthcare Ecosystems
C. Paper 2 - Revise your eHealth Platform!
D. Paper 3 - Business Model Open ”E-Health-Platform”
E. Paper 4 - Modelling Ecosystems in Information Systems
F. Paper 5 - Designing Industrial Symbiosis Platforms
G. Paper 6 - Management of Digital Ecosystems with DREEM
H. Paper 7 - Guiding the Development of Digital Ecosystems
I. Paper 8 - Towards Maintenance Analytics Ecosystems
J. Paper 9- Sustainability of E-Health-Projects
K. Paper 10 - ISO 11354-2 for the Evaluation of eHealth-Platform
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Developing, testing and refining a physiotherapy model of care for acute low back pain
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis is concerned with the physiotherapy management of acute low back pain. Various national guidelines contain conflicting views regarding the role of physiotherapy in the management of acute low back pain. The discrepancies involve primarily the content and timing of physiotherapy intervention. There is a need to place the physiotherapy management of acute low back pain on a more firm research base. A comprehensive literature review was undertaken to develop a best practice model of care for acute low back pain. This model was tested in a randomised controlled trial. Subjects involved in the treatment model demonstrated significantly better short-term outcomes than subjects given advice only. Furthermore, subjects treated early demonstrated significantly better long-term
outcome than subjects who waited six weeks for their treatment. Changes in pain and
physical function were found to be the factors most closely associated with good outcome in the short-term. Good outcome in the long term was associated with improvement in a number of physical and psychological variables. It is recommended that changes be made to the treatment model to facilitate improvement in pain relief and maintenance of physical and social function to further enhance treatment effectiveness.This study was funded by a grant from the NHS R&D committee
Asymptotics of continuous-time discrete state space branching processes for large initial state
Scaling limits for continuous-time branching processes with discrete state
space are provided as the initial state tends to infinity. Depending on the
finiteness or non-finiteness of the mean and/or the variance of the offspring
distribution, the limits are in general time-inhomogeneous Gaussian processes,
time-inhomogeneous generalized Ornstein-Uhlenbeck type processes or
continuous-state branching processes. We also provide transfer results showing
how specific asymptotic relations for the probability generating function of
the offspring distribution carry over to those of the one-dimensional
distributions of the branching process
ISO 11354-2 FOR THE EVALUATION OF EHEALTH PLATFORMS
Open software platforms are a recent innovation in the healthcare sector to foster integrated care scenarios. An important quality feature to facilitate innovation and to create an active platform ecosystem is openness. The openness is strongly influenced by the interoperability potential of the platforms. Hence, the assessment of the interoperability potential is a crucial task for evaluating the quality of platforms. However, there is a need for methodological support fostering the evaluation of eHealth platforms. Based on a design science research approach, the article shows, how the Maturity Model for Enterprise Interoperability (ISO 11353-2) can be instantiated in the healthcare domain. We describe a quantitative evaluation model which operationalizes the evaluation process of eHealth platforms. The contribution purposes to improve the transparency and reliability of the evaluation process. Furthermore, the introduced approach reduces the dependence on an evaluation team and facilitates the implementation of assessments
Towards Model Driven Architecture in Health Care Information System Development
Failed software projects are often the result of an unsystematic transfer of business requirements to the implementation. This deficit led to the specification of the Model Driven Architecture (MDA). It claims a consistent use of conceptual models for the software development process from requirement analysis to technical specification of software. The MDA reduces the gap between the business level and the information technology (IT) level by defining a methodological framework to link these levels (Business-IT alignment). We will present the use of an MDA in health care domain. For this purpose, we show how the paradigm of MDA can be configured to implement medical application software based on a telemedical IT platform (telehealth platform). Additionally to the conceptual structure of the developed approach and the domain-specific alignment, lessons learned from the experiences gathered during design process will be formulated as assistance for similar projects and substantiated with an exemplary application
A Standard Mission Profile for Hybrid-Electric Regional Aircraft based on Web Flight Data
To reduce emissions of air traffic, future aircraft will install hybrid-electric propulsion systems. We require the load conditions over the time in service, to design these aircraft. In this paper, we propose a mission profile for a regional aircraft with a hybrid-electric propulsion system. We focused on regional aircraft, which are in service in Ireland and the United Kingdom (UK). The reference aircraft ATR\,72-600 is a turboprop aircraft with a capacity of 70 passengers. To propose a mission profile, we have analyzed more than 6000 flights of four different aircraft of the same type. Input data is provided by online databases, which collect flight data. We are able to show that the maximum available power is needed for about 52 seconds during take-off and climb phase of the flight. The median flight time is 59 minutes and 30 seconds. The average required power is 53\,\% of the maximum power. The average traveled distance is 407\,km, which is less than one third of the aircraft\u27s maximum reach. These findings are needed for calculating the lifetime of drivetrain components of a hybrid or all electric aircraft. In our further work, we will design an electric machine for regional aircraft. This mission profile will be used to design different power train components
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