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Cloud-Based Optimal Control of Individual Borehole Heat Exchangers in a Geothermal Field

Journal of Thermal Science 2022年第5期31卷 1253-1265页

作者： STOFFEL Phillip KÜMPEL Alexander MÜLLER dirk RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor Climate52074 AachenGermany

Integrating renewable energy sources is a crucial component in reducing CO_(2) emissions in the building sector. In particular, shallow geothermal energy is expected to play a significant role in the regenerative energy supply of buildings. An effective control strategy for the geothermal field is crucial to reduce the overall energy consumption. This paper analyzes the benefits of controlling an existing field’s individual borehole heat exchangers(BHE) using nonlinear model predictive control(NMPC) and moving horizon estimation. The considered geothermal field consists of 41 BHEs and is used for heating and cooling. Each BHE is equipped with temperature sensors for in-and outflow and has individually controllable valves, while a central hydraulic pump feeds all BHEs. The sensor measurements are accessed through a cloud platform, enabling also set point writing for the pump speed and the valve positions. To control the BHEs individually, we propose a two-stage process. In the calibration stage, a moving horizon estimator estimates the actual borehole and ground temperatures for each BHE. In the second stage, first, a nonlinear model predictive controller optimizes the number of active BHEs necessary to meet the buildings’ energy demand. With the estimated ground temperatures as a basis, it is determined which BHEs shall be(de)-activated. The active BHEs are fed with a fixed volume flow of 24 L/min to ensure turbulent heat transfer. To reduce the power usage of the pumps, an optimal control problem based on a simple hydraulic model of the geothermal field is used. The methodology is analyzed through simulations first and then validated experimentally. The results show that half or more of the BHEs could be deactivated most of the time, leading to 67% savings in electricity consumption by the hydraulic pump. The experimental validation confirms the high energy saving potential of the proposed methodology, reducing the consumption of electrical energy by 71%. Additiona

关键词： geothermal energy moving horizon estimation model predictive control operation optimization optimal control

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Plausibility in Early Stages of Architectural Design: A New Tool for High-Rise Residential Buildings

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Tsinghua Science and Technology 2009年第3期14卷 327-332页

作者： dirk Donath Danny Lobos Chair of Computer Science in Architecture Faculty of Architecture Bauhaus-UniversityWeimar 99423 Germany

This paper analyzes the problem of the design of envelopes for high-rise isolated residential buildings. The phenomenon of envelope creation appears in the early stages of the architectural design. Variables that influence the final shape and size of such envelopes are then identified. This paper presents the state-of-the-art tools for the current solutions at the commercial and academic/scientific level. The variables identified in this research are the client＇s needs, the urban code and architectural practice, and their specific components for the final creation of a new decision support system tool based on the building information modeling （BIM） software platform, to facilitate the work in the project development and drawing production stages. This tool generates several options for building envelopes according to the parameters required by the city Zoning Planning Commission. These options then lead to deliver reliable data and a geometry that can be analyzed in a timely fashion by the engineers, builders, architects, government, and clients in the early stages of the building＇s design. The results show that use of specific information and communication technologies （ICT） tools in the early stages of a building design helps reduce the working time, increases confidence in the generated solution, and contributes to the exploration of alternatives in a short period of time.

关键词： constraint based design parametric programming urban modeling optimization architectural design

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An Efficient Calculation of Photonic Crystal Band Structures Using Taylor Expansions

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Communications in Computational Physics 2014年第10期16卷 1355-1388页

作者： dirk Klindworth Kersten Schmidt Research Center MATHEON TU BerlinDepartment of MathematicsStraße des 17.Juni 13610623 BerlinGermany.

In this paper we present an efficient algorithm for the calculation of photonic crystal band structures and band structures of photonic crystal *** method relies on the fact that the dispersion curves of the band structure are smooth functions of the quasi-momentum in the one-dimensional Brillouin *** show the derivation and computation of the group velocity,the group velocity dispersion,and any higher derivative of the dispersion *** derivatives are then employed in a Taylor expansion of the dispersion *** control the error of the Taylor expansion with the help of a residual estimate and introduce an adaptive scheme for the selection of nodes in the one-dimensional Brillouin zone at which we solve the underlying eigenvalue problem and compute the derivatives of the dispersion *** proposed algorithm is not only advantageous as it decreases the computational effort to compute the band structure but also because it allows for the identification of crossings and anti-crossings of dispersion curves,*** identification is not possible with the standard approach of solving the underlying eigenvalue problem at a discrete set of values of the quasi-momentum without taking the mode parity into account.

关键词： Photonic crystals band structure calculation group velocity Taylor expansion adaptivity

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Efficient Dynamic Floor Field Methods for Microscopic Pedestrian Crowd Simulations

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Communications in Computational Physics 2014年第6期16卷 264-286页

作者： dirk Hartmann Peter Hasel Siemens AG Corporate Technology80200 MunichGermany

Floor field methods are one of the most popular medium-scale navigation concepts in microscopic pedestrian *** introduced dynamic floor field methods have significantly increased the realism of such simulations,*** of spatio-temporal patterns of pedestrian densities in simulations with real world *** methods update floor fields continuously taking other pedestrians into *** implies that computational times are mainly determined by the calculation of floor *** this work,we propose a new computational approach for the construction of dynamic floor *** approach is based on the one hand on adaptive grid concepts and on the other hand on a directed calculation of floor fields,*** calculation is restricted to the domain of *** both techniques the computational complexity can be reduced by a factor of 10 as demonstrated by several realistic *** on-line simulations,a requirement of many applications,are possible for moderate realistic scenarios.

关键词： Pedestrian dynamics cellular automata adaptive grids floor field methods fast marching method navigation.

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How commercial involvement affects open source projects:three case studies on issue reporting

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Science China(Information Sciences) 2013年第8期56卷 153-165页

作者： MA XiuJuan ZHOU MingHui RIEHLE dirk School of Electronics Engineering and Computer Science Peking University Key Laboratory of High Confidence Software Technologies Ministry of Education Friedrich-Alexander-University of Erlangen-Nurnberg

Whereas most research on Internetware has focused on new technologies for keeping track of a changing Internet,little attention has been paid to the software development process.A large portion of the software running the Internet is open source *** source software is developed both by volunteers and commercial companies,often *** get involved in open source projects for commercial reasons,and bring with them a commercial software development ***,it is important to understand how commercial involvement affects the software development process of open source *** article presents case studies of three open source application servers that are being developed jointly by a volunteer community and one primary software *** are interested in better understanding developer behavior,specifically task distribution and performance,based on whether the developer is an external contributor,e.g.,a volunteer working in their spare time,or a commercial developer from inside the primary backing company who is being paid for their *** achieve this,we look at issue reporting as an example of commercial involvement in open source *** particular,we investigate the distribution of tasks among volunteers and commercial developers by studying the source of reported issues and quantify the task performance on user experience via the issue resolution *** construct measures based on historical records in issue tracking *** results show that,with intensified commercial involvement,the majority of issue reporting tasks would be undertaken by commercial developers,and issue resolution time would be reduced,implying a better user *** hope our methods and results provide practical insights for designing an efficient hybrid development process in the Internetware environment.

关键词： open source software development commercial involvement hybrid development contributor participation issue reporting

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Current Developments in Cognitive Linguistics

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外国语 2008年第3期31卷 2-19页

作者： dirk Geeraerts University of Leuven Belgium

After 30 years of theoretical development,we need to address the question whether the internal evolution of Cognitive Linguistics can be synthesized:what are the fundamental underlying trends in Cognitive Linguistics,and how do they shape the current developments within Cognitive Linguistics This paper argues that Cognitive Linguistics is essentially characterized by a gradual recontextualization of the ***,the development of 20th century grammar is characterized by a succession of a decontextualizing and a recontextualizing ***,the various stages in the development of Cognitive Linguistics involve the gradual recovery of the various types of context that were discarded by generative *** involve the experiential and embodied context of meaning in natural language,the pragmatic context of actual language usage,and the social and cultural context of language as a shared code.

关键词：语言学外语教学方法发展现状

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Nanotribological studies using nanoparticle manipulation: Principles and application to structural lubricity

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Friction 2014年第2期2卷 114-139页

作者： dirk DIETZEL Udo DSCHWARZ AndréSCHIRMEISEN Institute of Applied Physics(IAP) Justus-Liebig-Universität GiessenGermany Departments of Mechanical Engineering&Materials Science and Chemical&Environmental Engineering and Center for Research on Structures and Phenomena(CRISP) Yale UniversityNew HavenCTUSA

The term“structural lubricity”denotes a fundamental concept where the friction between two atomically flat surfaces is reduced due to lattice mismatch at the *** favorable circumstances,its effect may cause a contact to experience ultra-low friction,which is why it is also referred to as“superlubricity”.While the basic principle is intriguingly simple,the experimental analysis of structural lubricity has been *** of the main reasons for this predicament is that the tool most frequently used in nanotribology,the friction force microscope,is not well suited to analyse the friction of extended *** overcome this deficiency,substantial efforts have been directed in recent years towards establishing nanoparticle manipulation techniques,where the friction of nanoparticles sliding on a substrate is measured,as an alternative approach to nanotribological *** choosing appropriate nanoparticles and substrates,interfaces exhibiting the characteristics needed for the occurrence of structural lubricity can be *** a consequence,nanoparticle manipulation experiments such as in this review represent a unique opportunity to study the physical conditions and processes necessary to establish structural lubricity,thereby opening a path to exploit this effect in technological applications.

关键词： Nanotribology nanoparticle manipulation friction force microscopy structural lubricity superlubricity HOPG

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Monitoring travel patterns in German city regions with the help of mobile phone network data

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International Journal of Digital Earth 2021年第3期14卷 379-399页

作者： Stefan Fina Jigeeshu Joshi dirk Wittowsky ILS-Research Institute for Regional and Urban Development gGmbH RWTH Aachen UniversityDortmundGermany German Aerospace Center DLR Berlin BerlinGermany Institute of Mobility and Urban Planning University Duisburg-EssenEssenGermany

This paper discusses the possibility to use mobile phone network data to monitor spatial policies in land use and transport *** requires robust time series and reproducible concepts linking spatial policies to monitoring outcomes,a requirement differing from current literature where mobile phone data analysis is exemplified in selected areas with privileged data *** need to serve the evaluation of policy objectives,for example in regional or local area *** this study,we,therefore,extend the application of mobile phone network data to monitoring applications comparing urban settlement types and their characteristic mobility *** accomplish this,we link mobile phone records with urban classifications and transport network data,using both visual and computational approaches to mine the *** article presents comparisons of travel patterns for selected monocentric and polycentric city regions in Germany,testing hypotheses of transit-oriented regional development,as well as testing for congestion risks in the transport *** results help us to gain a more detailed understanding of spatial and temporal patterns in mobility for different urban types and assess future potentials for monitoring spatial policies with mobile phone network data.

关键词： Mobile phone network data big data urban mobility visual analytics congestion analysis spatial and temporal analysis GIS

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Migration to Intermediate XML for Electronic Data (MIXED)

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现代图书情报技术 2008年第1期 21-32页

作者： dirk ROORDA Data Archiving and Networked Services (DANS) NL

MIXED is a digital preservation project. It uses a strategy of converting data to intermediate XML. In this paper we position this strategy with respect to the well-known emulation and migration strategies. Then we detail the MIXED strategy and explain why it is an optimized, economical way of migration. Finally, we describe how DANS is implementing a software tool that can perform the migrations needed for this strategy.

关键词：电子数据数字资源长期保存迁移文件格式软件开发 XML MIXED 图书馆

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Smoking prevalence in the area of responsibility of the German Ministry of Defense——results of the employee survey in the context of occupational health management

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Military Medical Research 2020年第3期7卷 343-349页

作者： Stefan Sammito Annika Claus dirk-Matthias Rose Department I 3 Research&Development Air Force Centre of Aerospace MedicineCologneGermany Occupational Medicine Faculty of MedicineOtto-von-Guericke-University of MagdeburgMagdeburgGermany Institute for Teachers’Health Institute of OccupationalSocial and Environmental Medicine of the Johannes-Gutenberg University MainzMainzGermany

Background:Tobacco use,correlated with reduced physical fitness,is one of the leading causes of avoidable death *** increases the risk of dementia and can shorten the lifespan by 10 *** the German Armed Forces(Bundeswehr),figures on smoking behavior have not been comprehensively *** study analyzes current data in a large sample from this ***:Based on an employee survey as part of the Occupational Health Management System,data on smoking behavior from 13,326 participants were analyzed in relation to age,gender,professional status,education level and membership in military operational units versus other ***:Smoking behavior varied significantly(Polder),gender,professional status,military agency membership status,and education level(the lower the education level,the higher the smoking rates).With the exception of the downward trend in smoking behavior with increasing age among civilian employees,these results were all significant(P<0.005).Conclusions:This data analysis shows that smoking prevalence among personnel in the area of responsibility of the Federal Ministry of Defense is comparable to the current data from corresponding surveys of the German *** on gender,they generally show values that are slightly above those of the German *** well-known trend in the general population of decreasing smoking prevalence with increasing age is also seen in this ***,there are considerable differences in the smoking prevalence among individual subgroups(professional status,agency,gender,education level).The data show that particular young soldiers in the armed forces should be the target group for further preventive measures.

关键词： Prevention Smoking Military Health promotion

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