１ Ｂａｓｉｃ ｎｅｐｈｒｏｌｏｇｙ（生理；免疫・病理；分子生物学；検査・診断） ２ Ｃｌｉｎｉｃａｌ ｎｅｐｈｒｏｌｏｇｙ（糸球体障害；尿細管・間質障害；全身性疾患と腎障害；水電解質異常；腎不全）

Annual review 腎臓

Change by Design : How Design Thinking Transforms Organizations and Inspires Innovation

A composite neural network that learns from multi-fidelity data: Application to function approximation and inverse PDE problems

The global response to warming of 1.5oC comprises transitions in land and ecosystem, energy, urban and infrastructure, and industrial systems. The feasibility of mitigation and adaptation options, and the enabling conditions for strengthening and implementing the systemic changes, are assessed in this chapter.

Strengthening and Implementing the Global Response

Simulations are often computationally expensive and the need for multiple realizations, as in uncertainty quantification or optimization, makes surrogate models an attractive option. For expensive high-fidelity models (HFMs), however, even performing the number of simulations needed for fitting a surrogate may be too expensive. Inexpensive but less accurate low-fidelity models (LFMs) are often also available. Multi-fidelity models (MFMs) combine HFMs and LFMs in order to achieve accuracy at a reasonable cost. With the increasing popularity of MFMs in mind, the aim of this paper is to summarize the state-of-the-art of MFM trends. For this purpose, publications in this field are classified based on application, surrogate selection if any, the difference between fidelities, the method used to combine these fidelities, the field of application and the year published. 
Available methods of combining fidelities are also reviewed, focusing our attention especially on multi-fidelity surrogate models in which fidelities are combined inside a surrogate model. Computation time savings are usually the reason for using MFMs, hence it is important to properly report the achieved savings. Unfortunately, we find that many papers do not present sufficient information to determine these savings. Therefore, the paper also includes guidelines for authors to present their MFM savings in a way that is useful to future MFM users. Based on papers that provided enough information, we find that time savings are highly problem dependent and that MFM methods we surveyed provided time savings up to 90%. 
Keywords: Multi-fidelity, Variable-complexity, Variable-fidelity, Surrogate models, Optimization, Uncertainty quantification, Review, Survey

Review of multi-fidelity models

A standardized data model as common language for disciplinary communication in aircraft design could have a significant impact on the efficiency of conceptual/preliminary design efforts and collaborative research in aircraft design. This paper discusses if such a standard could be established and under which circumstances this would make sense. The Common Parametric Aircraft Configuration Scheme (CPACS) is introduced as one potential step towards a unified data model. Experiences in coupling established Multidisciplinary Design Optimization (MDO) environments with CPACS are presented and requirements for setting a standard are discussed.

Communication in aircraft design : Can we establish a common language?

Robustness analysis metrics for worldwide airport network: A comprehensive study

In the present study we introduce a design environment consisting of a framework, a central model and a newly developed conceptual design module. The Common Parametric Aircraft Configuration Scheme (CPACS) is the standard syntax definition for the exchange of information within preliminary airplane design at DLR. Several higher fidelity analysis modules are already connected to CPACS, including aerodynamics, primary structures, mission analysis and climate impact. The analysis modules can be interfaced via a distributed framework. To initialize the design processes, capabilities are needed to close the gap between top-level requirements and preliminary design. Additionally, results of a design loop need to be merged to generate inputs for further iterations and convergence control. For this purpose we developed a conceptual design module based on handbook methods where the focus is set on multi-fidelity. For the upward change in level of detail a knowledge-based approach is used for the generation of CPACS models. This includes the geometry generation, as well as additional data such as the mass breakdown and the tool-specific inputs for further analyses in higher fidelity modules. The feedback loop is closed downwards by reducing the granularity from the CPACS data set back to the level of conceptual design methods. The conceptual design module is object-oriented and concepts, both for parameter and method replacement, are introduced. First results for multi-fidelity calculations are shown.

An approach to multi-fidelity in conceptual aircraft design in distributed design environments

Aviation guarantees mobility, but its emissions also contribute considerably to climate change. Therefore, climate impact mitigation strategies have to be developed based on comprehensive assessments of the different impacting factors. We quantify the climate impact mitigation potential and related costs resulting from changes in aircraft operations and design using a multi-disciplinary model workflow. We first analyze the climate impact mitigation potential and cash operating cost changes of altered cruise altitudes and speeds for all flights globally operated by the Airbus A330-200 fleet in the year 2006. We find that this globally can lead to a 42% reduction in temperature response at a 10% cash operating cost increase. Based on this analysis, new design criteria are derived for future aircraft that are optimized for cruise conditions with reduced climate impact. The newly-optimized aircraft is re-assessed with the developed model workflow. We obtain additional climate mitigation potential with small to moderate cash operating cost changes due to the aircraft design changes of, e.g., a 32% and 54% temperature response reduction for a 0% and 10% cash operating cost increase. Hence, replacing the entire A330-200 fleet by this redesigned aircraft ( M a c r = 0.72 and initial cruise altitude (ICA) = 8000 m) could reduce the climate impact by 32% without an increase of cash operating cost.

Volker Gollnick

Papers

Communication in aircraft design : Can we establish a common language?

Robustness analysis metrics for worldwide airport network: A comprehensive study

An approach to multi-fidelity in conceptual aircraft design in distributed design environments

Climate-Compatible Air Transport System—Climate Impact Mitigation Potential for Actual and Future Aircraft

Economic-environmental trade-offs in long-term airline fleet planning