Refine
Document Type
- Article (1015) (remove)
Institute
- Professur Theorie und Geschichte der modernen Architektur (393)
- Institut für Strukturmechanik (ISM) (254)
- Professur Informatik im Bauwesen (130)
- Professur Stochastik und Optimierung (40)
- Professur Bauphysik (23)
- In Zusammenarbeit mit der Bauhaus-Universität Weimar (21)
- Professur Informatik in der Architektur (15)
- Junior-Professur Computational Architecture (12)
- Institut für Europäische Urbanistik (11)
- Professur Bauchemie und Polymere Werkstoffe (11)
Keywords
- Bauhaus-Kolloquium (395)
- Weimar (395)
- Angewandte Mathematik (186)
- Strukturmechanik (185)
- Architektur (168)
- 1986 (63)
- 1989 (60)
- Design (59)
- Bauhaus (55)
- Raum (55)
Die thermodynamischen Grundlagen der Hydratation von Hüttensand als Hauptbestandteil von Zementen werden erforscht. Hierbei werden thermodynamische Bildungs- und Reaktionsdaten experimentell bestimmt und berechnet. Darüber hinaus wird der Prozess der Feststoffauflösung von Hüttensand in wässrigen Lösungen untersucht. Lösungs- und Fällungsprozesse werden unter verschiedenen Konditionen gemessen, ausgewertet und diskutiert. Die Ergebnisse werden im weiteren Verlauf zur Bestimmung der Hydratationsgrades in Pasten sowie zum besseren Verständnis in der Wechselwirkung zwischen Hüttensanden und Mahlhilfsstoffen genutzt und angewandt.
The described study aims to find correlations between urban spatial configurations and human emotions. To this end, the authors measured people’s emotions while they walk along a path in an urban area using an instrument that measures skin conductance and skin temperature. The corresponding locations of the test persons were measured recorded by using a GPS-tracker (n=13). The results are interpreted and categorized as measures for positive and negative emotional arousal. To evaluate the technical and methodological process. The test results offer initial evidence that certain spaces or spatial sequences do cause positive or negative emotional arousal while others are relatively neutral. To achieve the goal of the study, the outcome was used as a basis for the study of testing correlations between people’s emotional responses and urban spatial configurations represented by Isovist properties of the urban form. By using their model the authors can explain negative emotional arousal for certain places, but they couldn’t find a model to predict emotional responses for individual spatial configurations.
Broadband electromagnetic frequency or time domain sensor techniques present high potential for quantitative water content monitoring in porous media. Prior to in situ application, the impact of the relationship between the broadband electromagnetic properties of the porous material (clay-rock) and the water content on the frequency or time domain sensor response is required. For this purpose, dielectric properties of intact clay rock samples experimental determined in the frequency range from 1 MHz to 10 GHz were used as input data in 3-D numerical frequency domain finite element field calculations to model the one port broadband frequency or time domain transfer function for a three rods based sensor embedded in the clay-rock. The sensor response in terms of the reflection factor was analyzed in time domain with classical travel time analysis in combination with an empirical model according to Topp equation, as well as the theoretical Lichtenecker and Rother model (LRM) to estimate the volumetric water content. The mixture equation considering the appropriate porosity of the investigated material provide a practical and efficient approach for water content estimation based on classical travel time analysis with the onset-method. The inflection method is not recommended for water content estimation in electrical dispersive and absorptive material. Moreover, the results clearly indicate that effects due to coupling of the sensor to the material cannot be neglected. Coupling problems caused by an air gap lead to dramatic effects on water content estimation, even for submillimeter gaps. Thus, the quantitative determination of the in situ water content requires careful sensor installation in order to reach a perfect probe clay rock coupling.
The paper gives the results of scientific research, which, being based on probabilistic and statistical modeling, identifies the relationship of certain socio-economic factors and the number of people killed in road accidents in the Russian Federation regions. It notes the identity of processes in various fields, in which there is loss of life. Scientific methods and techniques were used in the process of data processing and study findings: systematic approach, methods of system analysis (algorithmization, mathematical programming) and mathematical statistics. The scientific novelty lies in the formulation, formalization and solving problems related to the analysis of regional road traffic accidents, its modeling taking into account the factors of socio-economic impact.
By allocating real estate investments into the logistics sector, investors highly participate in the economic development of the respective country or city. However, the submarket is very cyclical and special economic influences – such as growing online trade and new logistic networks – affect the performance of the properties. Important parameters on the potential returns are found not only within the real estate market, but also within the global economy and the development of specific industries. This paper aims at examining factors affecting the performance of logistics properties.
Expected dependencies between macroeconomic factors and real estate economic indicators are examined for six major European logistics locations using econometric models, especially correlation and regression. Data series over a period of 25 years were used. The construction of an econometric model was an iterative process integrating both the statistical result and the economic causality.
Durch Reifungs- und Strukturbildungsprozesse kann es bei silikatischen und alumosilikatischen Bindern zu Rissbildung bei behinderter Verformung, Festigkeitsverlust und somit Verlust der Dauerhaftigkeit kommen. Die Bewertung dieser Prozesse erfolgt an silikatischen Materialien mit einem Ausblick auf die alumosilikatischen Binder.
Durch Reifungs- und Strukturbildungsprozesse kann es bei silikatischen und alumosilikatischen Bindern zu Rissbildung bei behinderter Verformung, Festigkeitsverlust und somit Verlust der Dauerhaftigkeit kommen. Die Bewertung dieser Prozesse erfolgt an silikatischen Materialien mit einem Ausblick auf die alumosilikatischen Binder
Traditionally, buildings in the Inner Himalayan valleys of Bhutan were constructed from rammed earth in the western regions and quarry stone in the central and eastern regions. Whilst basic architectural design elements have been retained, the construction methods have however changed over recent decades alongside expectations for indoor thermal comfort. Nevertheless, despite the need for space heating, thermal building performance remains largely unknown. Furthermore, no dedicated climate data is available for building performance assessments. This paper establishes such climatological information for the capital Thimphu and presents an investigation of building physics properties of traditional and contemporary building types. In a one month field study 10 buildings were surveyed, looking at building air tightness, indoor climate, wall U-values and water absorption of typical wall construction materials. The findings highlight comparably high wall U-values of 1.0 to 1.5 W/m²K for both current and historic constructions. Furthermore, air tightness tests show that, due to poorly sealed joints between construction elements, windows and doors, many buildings have high infiltration rates, reaching up to 5 air changes per hour. However, the results also indicate an indoor climate moderating effect of more traditional earth construction techniques. Based on these survey findings basic improvements are being suggested.
Development of sustainable urban environments assumes processing of large amount of data from various sources. It could be field study observations, results of simulations or information provided by modeling. This paper focuses on processing modeled data of pedestrian movement based on existed axial maps of particular environment. Introduced component allows further analysis by calculation of set of metrics based on inverted graph, which is built from given paths.
The work has studied the structure and properties of gypsum compositions modified with the manmade modifier based on metallurgical dust and multi-walled carbon nanotubes. The results show that changing the structure of solid gypsum leads to the increase in bending and compressive strength by 70,5% and 138% correspondingly, the water resistance increasing and the softening factor reaching 0,85. Modifying gypsum composition with complex additive leads to the formation of amorphous structures based on calcium hydrosilicates on the surface of primary gypsum crystallohydrates that bond gypsum crystals and reduce the access of water.
Maturation and Structure Formation Processes in Binders with Aqueous Alkali-Silicate Solutions
(2017)
Maturation and structure formation processes can lead to crack formation in silicate and aluminosilicate binders (e.g. for coating materials...) through restricted deformation, loss of strength and thus to loss of durability. These processes are evaluated with silicate materials with an outlook on aluminosilicate binders.
Welche Zukünfte?
(2017)
The fire resistance of concrete members is controlled by the temperature distribution of the considered cross section. The thermal analysis can be performed with the advanced temperature dependent physical properties provided by 5EN6 1992-1-2. But the recalculation of laboratory tests on columns from 5TU6 Braunschweig shows, that there are deviations between the calculated and measured temperatures. Therefore it can be assumed, that the mathematical formulation of these thermal properties could be improved. A sensitivity analysis is performed to identify the governing parameters of the temperature calculation and a nonlinear optimization method is used to enhance the formulation of the thermal properties. The proposed simplified properties are partly validated by the recalculation of measured temperatures of concrete columns. These first results show, that the scatter of the differences from the calculated to the measured temperatures can be reduced by the proposed simple model for the thermal analysis of concrete.
Tensile strain and compress strain can greatly affect the thermal conductivity of graphene nanoribbons (GNRs). However, the effect of GNRs under shear strain, which is also one of the main strain effect, has not been studied systematically yet. In this work, we employ reverse nonequilibrium molecular dynamics (RNEMD) to the systematical study of the thermal conductivity of GNRs (with model size of 4 nm × 15 nm) under the shear strain. Our studies show that the thermal conductivity of GNRs is not sensitive to the shear strain, and the thermal conductivity decreases only 12–16% before the pristine structure is broken. Furthermore, the phonon frequency and the change of the micro-structure of GNRs, such as band angel and bond length, are analyzed to explore the tendency of thermal conductivity. The results show that the main influence of shear strain is on the in-plane phonon density of states (PDOS), whose G band (higher frequency peaks) moved to the low frequency, thus the thermal conductivity is decreased. The unique thermal properties of GNRs under shear strains suggest their great potentials for graphene nanodevices and great potentials in the thermal managements and thermoelectric applications.
Im Aufsatz "Zwei Pater noster-Vertonungen von Melchior Vulpius und die Missa V. vocum super Pater noster qui es in Coelis Melchioris Vulpii von Georg Vintz" werden Pater noster-Vertonungen aus dem OPUSCULUM NOVUM SELECTISSIMARVUM CANTIONVM SACRARVM (Erfurt 1610) und aus der PARS PRIMA CANTIONVM SACRARVM (Jena 1602) des Weimarer Kantors und Komponisten Melchior Vulpius (1570 - 1615) besprochen und miteinander verglichen. Ebenso wird untersucht, in welcher Weise der Naumburger Organist Georg Vintz (ca. 1580 - ca. 1635) eine dieser Motetten als Grundlage für die Parodiemesse "MISSA V. VOCUM,Super Pater noster [...] Melchioris Vulpii" genutzt und bearbeitet hat.
Der Aufsatz beruht auf einem Vortrag bei einer Tagung über Vulpius, die 2015 in Meiningen stattfand. Der Tagungsband, den Maren Goltz herausgeben wird, erscheint vermutlich 2018. Da im Band nicht genügend Platz für ausführliche Notenbeispiele ist, werden die besprochenen Kompositionen vollständig als Noten- und Klangdateien durch diesen Permalink zur Verfügung gestellt.
One of the frequently examined design principles recommendations in multimedia learning is the personalization principle. Based on empirical evidence this principle states that using personalised messages in multimedia learning is more beneficial than using formal language (e.g. using ‘you’ instead of ‘the’). Although there is evidence that these slight changes in regard to the language style affect learning, motivation and the perceived cognitive load, it remains unclear, (1) whether the positive effects of personalised language can be transferred to all kinds of content of learning materials (e.g. specific potentially aversive health issues) and (2) which are the underlying processes (e.g. attention allocation) of the personalization effect. German university students (N= 37) learned symptoms and causes of cerebral haemorrhages either with a formal or a personalised version of the learning material. Analysis revealed comparable results to the few existing previous studies, indicating an inverted personalization effect for potentially aversive learning material. This effect was specifically revealed in regard to decreased average fixation duration and the number of fixations exclusively on the images in the personalised compared to the formal version. This result can be seen as indicators for an inverted effect of personalization on the level of visual attention.
Die Idee eines neuen Munizipalismus wird in den linken sozialen Bewegungen Europas und darüber hinaus breit diskutiert. Munizipalistische Bewegungen streben es an, kommunale Regierungen zu übernehmen oder zu beeinflussen, um lokale Institutionen (wieder) gemeinwohlorientiert auszurichten, ein neues Verhältnis zwischen kommunalen Regierungen und sozialen Bewegungen zu schaffen und so die Art wie Politik gestaltet wird von unten her zu demokratisieren und institutionelle Rahmenbedingungen zu verändern. Sie entstehen in Reaktion auf die aktuelle ökonomische und politische Krise – ebenso wie neue rechte und rechtspopulistische Bewegungen, als deren Gegenpart sie sich verstehen. Mit Mut und konkreten Utopien will man der multiplen städtischen Krise begegnen, statt mit Angst und Angstmacherei wie rechte Bewegungen. Deshalb trafen sich im Juni 2017 über 600 Vertreter_innen dieser munizipalistischen Bewegungen auf Einladung Barcelona en Comús.
Dieser Artikel analysiert, in welcher Weise sich die Weltkunstausstellung documenta 14 mit dem öffentlichen Raum in Kassel auseinandersetzte. Als Kritik an globalen Unrechtszuständen konzipiert, ging die diesjährige Documenta nicht auf die lokalen Umstände in Kassel ein und benutzte die Stadt stattdessen als Bühne. Statt sich mit den konkreten Prozessen vor Ort auseinanderzusetzen, wie die Ausstellung dies in Athen getan hat, wird die Tradition der Documenta gebrochen, einen Beitrag zur gesellschaftlichen Stadtentwicklung leisten zu wollen.
Elitenkritik, populare Bündnisse und inklusive Solidaritär. Interview zur Debatte um Linkspopulismus
(2018)
In der aktuellen ökonomischen und politischen Krise haben Debatten um linke Strategien wieder Hochkonjunktur. Besonders kontrovers werden Vorschläge diskutiert, die einen Linkspopulismus als Alternative zum rechten politischen Projekt, zum Neoliberalismus und als Transformationsstrategie hin zu einer sozialistischen Gesellschaft propagieren. Thomas Goes und Violetta Bock haben mit ihrem Buch Ein unanständiges Angebot? Mit linkem Populismus gegen Eliten und Rechte (2017) eine programmatische Aufarbeitung existierender linker Populismuskonzepte und ihre eigene Vorstellung davon, wie ein linker Populismus gelingen kann, vorgelegt. Damit haben sie die Debatte um Linkspopulismus in Deutschland befeuert. Im Interview werden sie nach ihren Positionen und den Kontroversen um das Buch befragt. Das Interview soll als Aufschlag für eine Debatte dienen. Antworten zu den dargestellten Positionen und Bezüge zu städtischen Themen und städtischen sozialen Bewegungen sind sehr willkommen.
Following restructuring of power industry, electricity supply to end-use customers has undergone fundamental changes. In the restructured power system, some of the responsibilities of the vertically integrated distribution companies have been assigned to network managers and retailers. Under the new situation, retailers are in charge of providing electrical energy to electricity consumers who have already signed contract with them. Retailers usually provide the required energy at a variable price, from wholesale electricity markets, forward contracts with energy producers, or distributed energy generators, and sell it at a fixed retail price to its clients. Different strategies are implemented by retailers to reduce the potential financial losses and risks associated with the uncertain nature of wholesale spot electricity market prices and electrical load of the consumers. In this paper, the strategic behavior of retailers in implementing forward contracts, distributed energy sources, and demand-response programs with the aim of increasing their profit and reducing their risk, while keeping their retail prices as low as possible, is investigated. For this purpose, risk management problem of the retailer companies collaborating with wholesale electricity markets, is modeled through bi-level programming approach and a comprehensive framework for retail electricity pricing, considering customers’ constraints, is provided in this paper. In the first level of the proposed bi-level optimization problem, the retailer maximizes its expected profit for a given risk level of profit variability, while in the second level, the customers minimize their consumption costs. The proposed programming problem is modeled as Mixed Integer programming (MIP) problem and can be efficiently solved using available commercial solvers. The simulation results on a test case approve the effectiveness of the proposed demand-response program based on dynamic pricing approach on reducing the retailer’s risk and increasing its profit.
In this paper, the decision-making problem of the retailers under dynamic pricing approach for demand response integration have been investigated. The retailer was supposed to rely on forward contracts, DGs, and spot electricity market to supply the required active and reactive power of its customers. To verify the effectiveness of the proposed model, four schemes for retailer’s scheduling problem are considered and the resulted profit under each scheme are analyzed and compared. The simulation results on a test case indicate that providing more options for the retailer to buy the required power of its customers and increase its flexibility in buying energy from spot electricity market reduces the retailers’ risk and increases its profit. From the customers’ perspective also the retailers’accesstodifferentpowersupplysourcesmayleadtoareductionintheretailelectricityprices. Since the retailer would be able to decrease its electricity selling price to the customers without losing its profitability, with the aim of attracting more customers. Inthiswork,theconditionalvalueatrisk(CVaR)measureisusedforconsideringandquantifying riskinthedecision-makingproblems. Amongallthepossibleoptioninfrontoftheretailertooptimize its profit and risk, demand response programs are the most beneficial option for both retailer and its customers. The simulation results on the case study prove that implementing dynamic pricing approach on retail electricity prices to integrate demand response programs can successfully provoke customers to shift their flexible demand from peak-load hours to mid-load and low-load hours. Comparing the simulation results of the third and fourth schemes evidences the impact of DRPs and customers’ load shifting on the reduction of retailer’s risk, as well as the reduction of retailer’s payment to contract holders, DG owners, and spot electricity market. Furthermore, the numerical results imply on the potential of reducing average retail prices up to 8%, under demand response activation. Consequently, it provides a win–win solution for both retailer and its customers.
Management strategies for sustainable sugarcane production need to deal with the increasing complexity and variability of the whole sugar system. Moreover, they need to accommodate the multiple goals of different industry sectors and the wider community. Traditional disciplinary approaches are unable to provide integrated management solutions, and an approach based on whole systems analysis is essential to bring about beneficial change to industry and the community. The application of this approach to water management, environmental management and cane supply management is outlined, where the literature indicates that the application of extreme learning machine (ELM) has never been explored in this realm. Consequently, the leading objective of the current research was set to filling this gap by applying ELM to launch swift and accurate model for crop production data-driven. The key learning has been the need for innovation both in the technical aspects of system function underpinned by modelling of sugarcane growth. Therefore, the current study is an attempt to establish an integrate model using ELM to predict the concluding growth amount of sugarcane. Prediction results were evaluated and further compared with artificial neural network (ANN) and genetic programming models. Accuracy of the ELM model is calculated using the statistics indicators of Root Means Square Error (RMSE), Pearson Coefficient (r), and Coefficient of Determination (R2) with promising results of 0.8, 0.47, and 0.89, respectively. The results also show better generalization ability in addition to faster learning curve. Thus, proficiency of the ELM for supplementary work on advancement of prediction model for sugarcane growth was approved with promising results.
The production of a desired product needs an effective use of the experimental model. The present study proposes an extreme learning machine (ELM) and a support vector machine (SVM) integrated with the response surface methodology (RSM) to solve the complexity in optimization and prediction of the ethyl ester and methyl ester production process. The novel hybrid models of ELM-RSM and ELM-SVM are further used as a case study to estimate the yield of methyl and ethyl esters through a trans-esterification process from waste cooking oil (WCO) based on American Society for Testing and Materials (ASTM) standards. The results of the prediction phase were also compared with artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS), which were recently developed by the second author of this study. Based on the results, an ELM with a correlation coefficient of 0.9815 and 0.9863 for methyl and ethyl esters, respectively, had a high estimation capability compared with that for SVM, ANNs, and ANFIS. Accordingly, the maximum production yield was obtained in the case of using ELM-RSM of 96.86% for ethyl ester at a temperature of 68.48 °C, a catalyst value of 1.15 wt. %, mixing intensity of 650.07 rpm, and an alcohol to oil molar ratio (A/O) of 5.77; for methyl ester, the production yield was 98.46% at a temperature of 67.62 °C, a catalyst value of 1.1 wt. %, mixing intensity of 709.42 rpm, and an A/O of 6.09. Therefore, ELM-RSM increased the production yield by 3.6% for ethyl ester and 3.1% for methyl ester, compared with those for the experimental data.
Biodiesel, as the main alternative fuel to diesel fuel which is produced from renewable and available resources, improves the engine emissions during combustion in diesel engines. In this study, the biodiesel is produced initially from waste cooking oil (WCO). The fuel samples are applied in a diesel engine and the engine performance has been considered from the viewpoint of exergy and energy approaches. Engine tests are performed at a constant 1500 rpm speed with various loads and fuel samples. The obtained experimental data are also applied to develop an artificial neural network (ANN) model. Response surface methodology (RSM) is employed to optimize the exergy and energy efficiencies. Based on the results of the energy analysis, optimal engine performance is obtained at 80% of full load in presence of B10 and B20 fuels. However, based on the exergy analysis results, optimal engine performance is obtained at 80% of full load in presence of B90 and B100 fuels. The optimum values of exergy and energy efficiencies are in the range of 25–30% of full load, which is the same as the calculated range obtained from mathematical modeling.
As part of an international research project – funded by the European Union – capillary glasses for facades are being developed exploiting storage energy by means of fluids flowing through the capillaries. To meet highest visual demands, acrylate adhesives and EVA films are tested as possible bonding materials for the glass setup. Especially non-destructive methods (visual analysis, analysis of birefringent properties and computed tomographic data) are applied to evaluate failure patterns as well as the long-term behavior considering climatic influences. The experimental investigations are presented after different loading periods, providing information of failure developments. In addition, detailed information and scientific findings on the application of computed tomographic analyses are presented.
Für eine Abschätzung des Heizwärmebedarfs von Gebäuden und Quartieren können thermisch-energetische Simulationen eingesetzt werden. Grundlage dieser Simulationen sind geometrische und physikalische Gebäudemodelle. Die Erstellung des geometrischen Modells erfolgt in der Regel auf Basis von Bauplänen oder Vor-Ort-Begehungen, was mit einem großen Recherche- und Modellierungsaufwand verbunden ist. Spätere bauliche Veränderungen des Gebäudes müssen häufig manuell in das Modell eingearbeitet werden, was den Arbeitsaufwand zusätzlich erhöht. Das physikalische Modell stellt die Menge an Parametern und Randbedingungen dar, welche durch Materialeigenschaften, Lage und Umgebungs-einflüsse gegeben sind. Die Verknüpfung beider Modelle wird innerhalb der entsprechenden Simulations-software realisiert und ist meist nicht in andere Softwareprodukte überführbar. Mithilfe des Building Information Modeling (BIM) können Simulationsdaten sowohl konsistent gespeichert als auch über Schnittstellen mit entsprechenden Anwendungen ausgetauscht werden. Hierfür wird eine Methode vorgestellt, die thermisch-energetische Simulationen auf Basis des standardisierten Übergabe-formats Industry Foundation Classes (IFC) inklusive anschließender Auswertungen ermöglicht. Dabei werden geometrische und physikalische Parameter direkt aus einem über den gesamten Lebenszyklus aktuellen Gebäudemodell extrahiert und an die Simulation übergeben. Dies beschleunigt den Simulations-prozess hinsichtlich der Gebäudemodellierung und nach späteren baulichen Veränderungen. Die erarbeite-te Methode beruht hierbei auf einfachen Modellierungskonventionen bei der Erstellung des Bauwerksinformationsmodells und stellt eine vollständige Übertragbarkeit der Eingangs- und Ausgangswerte sicher.
Thermal building simulation based on BIM-models. Thermal energetic simulations are used for the estimation of the heating demand of buildings and districts. These simulations are based on building models containing geometrical and physical information. The creation of geometrical models is usually based on existing construction plans or in situ assessments which demand a comparatively big effort of investigation and modeling. Alterations, which are later applied to the structure, request manual changes of the related model, which increases the effort additionally. The physical model represents the total amount of parameters and boundary conditions that are influenced by material properties, location and environmental influences on the building. The link between both models is realized within the correspondent simulation soft-ware and is usually not transferable to other software products. By Applying Building Information Modeling (BIM) simulation data is stored consistently and an exchange to other software is enabled. Therefore, a method which allows a thermal energetic simulation based on the exchange format Industry Foundation Classes (IFC) including an evaluation is presented. All geometrical and physical information are extracted directly from the building model that is kept up-to-date during its life cycle and transferred to the simulation. This accelerates the simulation process regarding the geometrical modeling and adjustments after later changes of the building. The developed method is based on simple conventions for the creation of the building model and ensures a complete transfer of all simulation data.
The Local Governance of Arrival in Leipzig: Housing of Asylum-Seeking Persons as a Contested Field
(2018)
The article examines how the German city of Leipzig governs the housing of asylum seekers. Leipzig was a frontrunner in organizing the decentralized accommodation of asylum seekers when adopting its accommodation concept in 2012. This concept aimed at integrating asylum-seeking persons in the regular housing market at an early stage of arrival. However, since then, the city of Leipzig faces more and more challenges in implementing the concept. This is particularly due to the increasingly tight situation on the housing market while the number of people seeking protection increased and partly due to discriminating and xenophobic attitudes on the side of house owners and managers. Therefore, we argue that the so-called refugee crisis of 2015–2016 has to be seen in close interaction with a growing general housing shortage in Leipzig like in many other large European cities. Furthermore, we understand the municipal governing of housing as a contested field regarding its entanglement of diverse federal levels and policy scales, the diversity of stakeholders involved, and its dynamic change over the last years. We analyze this contested field set against the current context of arrival and dynamic urban growth on a local level. Based on empirical qualitative research that was conducted by us in 2016, Leipzig’s local specifics will be investigated under the umbrella of our conceptual framework of Governance of Arrival. The issues of a strained housing market and the integration of asylum seekers in it do not apply only to Leipzig, but shed light on similar developments in other European Cities.
Die späten 1960er Jahre und vor allem die 1970er Jahre waren eine Hochphase der Mieter_innenproteste in der BRD. Dieser Beitrag verfolgt die These, dass die Krise der fordistischen Wohnraumversorgung in den 1960er Jahren, bzw. die von der Politik implementierten Lösungsstrategien dieser Krise, eine Klassenallianz in wohnungsbezogenen Protesten ermöglichte und, dass sich diese Klassenallianz im Laufe der 1970er und 1980er Jahre aufspaltete, was zur Einhegung des Protests in das entstehende neoliberale Projekt führte. Im Folgenden beschreibe ich also zunächst die Wohnungsfrage 1968 als Krise der fordistischen Wohnraumproduktion und damit die materielle Basis der Klassenallianz. Daran anschließend illustriere ich anhand von Protesten in den drei Bereichen Massenwohnungsbau, Sanierungsgebiete und Hausbesetzungen die Klassenallianz und vollziehe ich deren Aufspaltung nach. Und schließlich stelle ich die Frage, was heute aus dieser Geschichte gelernt werden kann.
Performance assessment of a ductless personalized ventilation system using a validated CFD model
(2018)
The aim of this study is twofold: to validate a computational fluid dynamics (CFD) model, and then to use the validated model to evaluate the performance of a ductless personalized ventilation (DPV) system. To validate the numerical model, a series of measurements was conducted in a climate chamber equipped with a thermal manikin. Various turbulence models, settings, and options were tested; simulation results were compared to the measured data to determine the turbulence model and solver settings that achieve the best agreement between the measured and simulated values. Subsequently, the validated CFD model was then used to evaluate the thermal environment and indoor air quality in a room equipped with a DPV system combined with displacement ventilation. Results from the numerical model were then used to quantify thermal sensation and comfort using the UC Berkeley thermal comfort model.
This study aims to develop an approach to couple a computational fluid dynamics (CFD) solver to the University of California, Berkeley (UCB) thermal comfort model to accurately evaluate thermal comfort. The coupling was made using an iterative JavaScript to automatically transfer data for each individual segment of the human body back and forth between the CFD solver and the UCB model until reaching convergence defined by a stopping criterion. The location from which data are transferred to the UCB model was determined using a new approach based on the temperature difference between subsequent points on the temperature profile curve in the vicinity of the body surface. This approach was used because the microclimate surrounding the human body differs in thickness depending on the body segment and the surrounding environment. To accurately simulate the thermal environment, the numerical model was validated beforehand using experimental data collected in a climate chamber equipped with a thermal manikin. Furthermore, an example of the practical implementations of this coupling is reported in this paper through radiant floor cooling simulation cases, in which overall and local thermal sensation and comfort were investigated using the coupled UCB model.
Auguste Rodins Weimarer Eva
(2018)
A broadband soil dielectric spectra retrieval approach ( 1 MHz– 2 GHz) has been implemented for a layered half space. The inversion kernel consists of a two-port transmission line forward model in the frequency domain and a constitutive material equation based on a power law soil mixture rule (Complex Refractive Index Model - CRIM). The spatially-distributed retrieval of broadband dielectric spectra was achieved with a global optimization approach based on a Shuffled Complex Evolution (SCE) algorithm using the full set of the scattering parameters. For each layer, the broadband dielectric spectra were retrieved with the corresponding parameters thickness, porosity, water saturation and electrical conductivity of the aqueous pore solution. For the validation of the approach, a coaxial transmission line cell measured with a network analyzer was used. The possibilities and limitations of the inverse parameter estimation were numerically analyzed in four scenarios. Expected and retrieved layer thicknesses, soil properties and broadband dielectric spectra in each scenario were in reasonable agreement. Hence, the model is suitable for an estimation of in-homogeneous material parameter distributions. Moreover, the proposed frequency domain approach allows an automatic adaptation of layer number and thickness or regular grids in time and/or space.
Für eine Abschätzung des Heizwärmebedarfs von Gebäuden und Quartieren können thermisch-energetische Simulationen eingesetzt werden. Grundlage dieser Simulationen sind geometrische und physikalische Gebäudemodelle. Die Erstellung des geometrischen Modells erfolgt in der Regel auf Basis von Bauplänen oder Vor-Ort-Begehungen, was mit einem großen Recherche- und Modellierungsaufwand verbunden ist. Spätere bauliche Veränderungen des Gebäudes müssen häufig manuell in das Modell eingearbeitet werden, was den Arbeitsaufwand zusätzlich erhöht. Das physikalische Modell stellt die Menge an Parametern und Randbedingungen dar, welche durch Materialeigenschaften, Lage und Umgebungs-einflüsse gegeben sind. Die Verknüpfung beider Modelle wird innerhalb der entsprechenden Simulations-software realisiert und ist meist nicht in andere Softwareprodukte überführbar.
Mithilfe des Building Information Modeling (BIM) können Simulationsdaten sowohl konsistent gespeichert als auch über Schnittstellen mit entsprechenden Anwendungen ausgetauscht werden. Hierfür wird eine Methode vorgestellt, die thermisch-energetische Simulationen auf Basis des standardisierten Übergabe-formats Industry Foundation Classes (IFC) inklusive anschließender Auswertungen ermöglicht. Dabei werden geometrische und physikalische Parameter direkt aus einem über den gesamten Lebenszyklus aktuellen Gebäudemodell extrahiert und an die Simulation übergeben. Dies beschleunigt den Simulations-prozess hinsichtlich der Gebäudemodellierung und nach späteren baulichen Veränderungen. Die erarbeite-te Methode beruht hierbei auf einfachen Modellierungskonventionen bei der Erstellung des Bauwerksinformationsmodells und stellt eine vollständige Übertragbarkeit der Eingangs- und Ausgangswerte sicher.
Thermal building simulation based on BIM-models. Thermal energetic simulations are used for the estimation of the heating demand of buildings and districts. These simulations are based on building models containing geometrical and physical information. The creation of geometrical models is usually based on existing construction plans or in situ assessments which demand a comparatively big effort of investigation and modeling. Alterations, which are later applied to the structure, request manual changes of the related model, which increases the effort additionally. The physical model represents the total amount of parameters and boundary conditions that are influenced by material properties, location and environmental influences on the building. The link between both models is realized within the correspondent simulation soft-ware and is usually not transferable to other software products.
By Applying Building Information Modeling (BIM) simulation data is stored consistently and an exchange to other software is enabled. Therefore, a method which allows a thermal energetic simulation based on the exchange format Industry Foundation Classes (IFC) including an evaluation is presented. All geometrical and physical information are extracted directly from the building model that is kept up-to-date during its life cycle and transferred to the simulation. This accelerates the simulation process regarding the geometrical modeling and adjustments after later changes of the building. The developed method is based on simple conventions for the creation of the building model and ensures a complete transfer of all simulation data.
Wireless sensor networks have attracted great attention for applications in structural health monitoring due to their ease of use, flexibility of deployment, and cost-effectiveness. This paper presents a software framework for WiFi-based wireless sensor networks composed of low-cost mass market single-board computers. A number of specific system-level software components were developed to enable robust data acquisition, data processing, sensor network communication, and timing with a focus on structural health monitoring (SHM) applications. The framework was validated on Raspberry Pi computers, and its performance was studied in detail. The paper presents several characteristics of the measurement quality such as sampling accuracy and time synchronization and discusses the specific limitations of the system. The implementation includes a complementary smartphone application that is utilized for data acquisition, visualization, and analysis. A prototypical implementation further demonstrates the feasibility of integrating smartphones as data acquisition nodes into the network, utilizing their internal sensors. The measurement system was employed in several monitoring campaigns, three of which are documented in detail. The suitability of the system is evaluated based on comparisons of target quantities with reference measurements. The results indicate that the presented system can robustly achieve a measurement performance commensurate with that required in many typical SHM tasks such as modal identification. As such, it represents a cost-effective alternative to more traditional monitoring solutions.
Urban planners are often challenged with the task of developing design solutions which must meet multiple, and often contradictory, criteria. In this paper, we investigated the trade-offs between social, psychological, and energy potential of the fundamental elements of urban form: the street network and the building massing. Since formal mehods to evaluate urban form from the psychological and social point of view are not readily available, we developed a methodological framework to quantify these criteria as the first contribution in this paper. To evaluate the psychological potential, we conducted a three-tiered empirical study starting from real world environments and then abstracting them to virtual environments. In each context, the implicit (physiological) response and explicit (subjective) response of pedestrians were measured. To quantify the social potential, we developed a street network centrality-based measure of social accessibility.
For the energy potential, we created an energy model to analyze the impact of pure geometric form on the energy demand of the building stock. The second contribution of this work is a method to identify distinct clusters of urban form and, for each, explore the trade-offs between the select design criteria. We applied this method to two case studies identifying nine types of urban form and their respective potential trade-offs, which are directly applicable for the assessment of strategic decisions regarding urban form during the early planning stages.
A categorical perspective towards aerodynamic models for aeroelastic analyses of bridge decks
(2019)
Reliable modelling in structural engineering is crucial for the serviceability and safety of structures. A huge variety of aerodynamic models for aeroelastic analyses of bridges poses natural questions on their complexity and thus, quality. Moreover, a direct comparison of aerodynamic models is typically either not possible or senseless, as the models can be based on very different physical assumptions. Therefore, to address the question of principal comparability and complexity of models, a more abstract approach, accounting for the effect of basic physical assumptions, is necessary.
This paper presents an application of a recently introduced category theory-based modelling approach to a diverse set of models from bridge aerodynamics. Initially, the categorical approach is extended to allow an adequate description of aerodynamic models. Complexity of the selected aerodynamic models is evaluated, based on which model comparability is established. Finally, the utility of the approach for model comparison and characterisation is demonstrated on an illustrative example from bridge aeroelasticity. The outcome of this study is intended to serve as an alternative framework for model comparison and impact future model assessment studies of mathematical models for engineering applications.
Estimating the solubility of carbon dioxide in ionic liquids, using reliable models, is of paramount importance from both environmental and economic points of view. In this regard, the current research aims at evaluating the performance of two data-driven techniques, namely multilayer perceptron (MLP) and gene expression programming (GEP), for predicting the solubility of carbon dioxide (CO2) in ionic liquids (ILs) as the function of pressure, temperature, and four thermodynamical parameters of the ionic liquid. To develop the above techniques, 744 experimental data points derived from the literature including 13 ILs were used (80% of the points for training and 20% for validation). Two backpropagation-based methods, namely Levenberg–Marquardt (LM) and Bayesian Regularization (BR), were applied to optimize the MLP algorithm. Various statistical and graphical assessments were applied to check the credibility of the developed techniques. The results were then compared with those calculated using Peng–Robinson (PR) or Soave–Redlich–Kwong (SRK) equations of state (EoS). The highest coefficient of determination (R2 = 0.9965) and the lowest root mean square error (RMSE = 0.0116) were recorded for the MLP-LMA model on the full dataset (with a negligible difference to the MLP-BR model). The comparison of results from this model with the vastly applied thermodynamic equation of state models revealed slightly better performance, but the EoS approaches also performed well with R2 from 0.984 up to 0.996. Lastly, the newly established correlation based on the GEP model exhibited very satisfactory results with overall values of R2 = 0.9896 and RMSE = 0.0201.
Seit 50 Jahren wird über Erklärungsansätze für Gentrifizierung gestritten. Sehr viel länger schon wandert anlagesuchendes Kapital von einem
Ort zum anderen und hinterlässt dabei Investitionsruinen einerseits und Menschen, die durch Verdrängung ihr Zuhause verlieren, andererseits. Sehr viel kürzer erst wird der Begriff Gentrifizierung hier und da von sozialen Bewegungen aufgegriffen, die sich mit letzterem Phänomen auseinandersetzen.
In diesem Beitrag soll es nicht um die wissenschaftliche Debatte um Erklärungsansätze für Gentrifizierung und auch nicht um die wissenschaftliche Relevanz des Begriffes gehen, sondern um seine Rolle und Funktion in sozialen Bewegungen.
FCS-MBFLEACH: Designing an Energy-Aware Fault Detection System for Mobile Wireless Sensor Networks
(2019)
Wireless sensor networks (WSNs) include large-scale sensor nodes that are densely distributed over a geographical region that is completely randomized for monitoring, identifying, and analyzing physical events. The crucial challenge in wireless sensor networks is the very high dependence of the sensor nodes on limited battery power to exchange information wirelessly as well as the non-rechargeable battery of the wireless sensor nodes, which makes the management and monitoring of these nodes in terms of abnormal changes very difficult. These anomalies appear under faults, including hardware, software, anomalies, and attacks by raiders, all of which affect the comprehensiveness of the data collected by wireless sensor networks. Hence, a crucial contraption should be taken to detect the early faults in the network, despite the limitations of the sensor nodes. Machine learning methods include solutions that can be used to detect the sensor node faults in the network. The purpose of this study is to use several classification methods to compute the fault detection accuracy with different densities under two scenarios in regions of interest such as MB-FLEACH, one-class support vector machine (SVM), fuzzy one-class, or a combination of SVM and FCS-MBFLEACH methods. It should be noted that in the study so far, no super cluster head (SCH) selection has been performed to detect node faults in the network. The simulation outcomes demonstrate that the FCS-MBFLEACH method has the best performance in terms of the accuracy of fault detection, false-positive rate (FPR), average remaining energy, and network lifetime compared to other classification methods.
Rapid advancements of modern technologies put high demands on mathematical modelling of engineering systems. Typically, systems are no longer “simple” objects, but rather coupled systems involving multiphysics phenomena, the modelling of which involves coupling of models that describe different phenomena. After constructing a mathematical model, it is essential to analyse the correctness of the coupled models and to detect modelling errors compromising the final modelling result. Broadly, there are two classes of modelling errors: (a) errors related to abstract modelling, eg, conceptual errors concerning the coherence of a model as a whole and (b) errors related to concrete modelling or instance modelling, eg, questions of approximation quality and implementation. Instance modelling errors, on the one hand, are relatively well understood. Abstract modelling errors, on the other, are not appropriately addressed by modern modelling methodologies. The aim of this paper is to initiate a discussion on abstract approaches and their usability for mathematical modelling of engineering systems with the goal of making it possible to catch conceptual modelling errors early and automatically by computer assistant tools. To that end, we argue that it is necessary to identify and employ suitable mathematical abstractions to capture an accurate conceptual description of the process of modelling engineering systems.
This study aims to evaluate a new approach in modeling gully erosion susceptibility (GES) based on a deep learning neural network (DLNN) model and an ensemble particle swarm optimization (PSO) algorithm with DLNN (PSO-DLNN), comparing these approaches with common artificial neural network (ANN) and support vector machine (SVM) models in Shirahan watershed, Iran. For this purpose, 13 independent variables affecting GES in the study area, namely, altitude, slope, aspect, plan curvature, profile curvature, drainage density, distance from a river, land use, soil, lithology, rainfall, stream power index (SPI), and topographic wetness index (TWI), were prepared. A total of 132 gully erosion locations were identified during field visits. To implement the proposed model, the dataset was divided into the two categories of training (70%) and testing (30%). The results indicate that the area under the curve (AUC) value from receiver operating characteristic (ROC) considering the testing datasets of PSO-DLNN is 0.89, which indicates superb accuracy. The rest of the models are associated with optimal accuracy and have similar results to the PSO-DLNN model; the AUC values from ROC of DLNN, SVM, and ANN for the testing datasets are 0.87, 0.85, and 0.84, respectively. The efficiency of the proposed model in terms of prediction of GES was increased. Therefore, it can be concluded that the DLNN model and its ensemble with the PSO algorithm can be used as a novel and practical method to predict gully erosion susceptibility, which can help planners and managers to manage and reduce the risk of this phenomenon.