Stochastic fiber dynamics in a spatially semi-discrete setting

We investigate a spatially discrete surrogate model for the dynamics of a slender, elastic, inextensible fiber in turbulent flows. Deduced from a continuous space-time beam model for which no solution theory is available, it consists of a high-dimensional second order stochastic differential equation in time with a nonlinear algebraic constraint and an associated Lagrange multiplier term. We establish a suitable framework for the rigorous formulation and analysis of the semi-discrete model and prove existence and uniqueness of a global strong solution. The proof is based on an explicit representation of the Lagrange multiplier and on the observation that the obtained explicit drift term in the equation satisfies a one-sided linear growth condition on the constraint manifold. The theoretical analysis is complemented by numerical studies concerning the time discretization of our model. The performance of implicit Euler-type methods can be improved when using the explicit representation of the Lagrange multiplier to compute refined initial estimates for the Newton method applied in each time step.Comment: 20 pages; typos removed, references adde

Restrukturierung der kommunalen Dienstleistungsproduktion: Innovationsfähigkeit deutscher Kommunen in internationaler Perspektive

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Continuous Non-Intrusive Hybrid WCET Estimation Using Waypoint Graphs

Traditionally, the Worst-Case Execution Time (WCET) of Embedded Software has been estimated using analytical approaches. This is effective, if good models of the processor/System-on-Chip (SoC) architecture exist. Unfortunately, modern high performance SoCs often contain unpredictable and/or undocumented components that influence the timing behaviour. Thus, analytical results for such processors are unrealistically pessimistic. One possible alternative approach seems to be hybrid WCET analysis, where measurement data together with an analytical approach is used to estimate worst-case behaviour. Previously, we demonstrated how continuous evaluation of basic block trace data can be used to produce detailed statistics of basic blocks in embedded software. In the meantime it has become clear that the trace data provided by modern SoCs delivers a different type of information. In this contribution, we show that even under realistic conditions, a meaningful analysis can be conducted with the trace data

Nätanslutning av vindkraft

Wind power is a growing energy sector in Sweden. However, it still represents only a small part of the total electricity production, about 0.7%. In order to create good conditions and to facilitate the establishment of wind power in Sweden, the government has for example, created a national centre for wind use. The objective has been to reach the governmental goal, which is an expansion of wind power by 10 TWh by year 2015 compared to the level in 2002. The Swedish electricity market was deregulated in 1996 which refers to the introduction of a competitive market in electricity production and trade. The electricity net business, however, continued to be a monopoly as it was considered to be too expensive to draw new electrical cables. The wind power companies are dependent on net companies to be able to transfer the produced electricity out on the net, to the market so to speak. Feasibility studies in this study show that some wind power companies experience the connection process as troublesome and the set of laws around this to be problematic. The purpose of this study is to contribute in a governmental investigation of mapping how the present set of laws creates obstacle for large scale developments and expansion of renewable electricity production. This study has investigated how actors within the wind power production experience the set of laws concerning net connection. Furthermore it sets out to describe the consequences of regulations. In an early stage of this project, it appeared that representatives of wind power companies felt that there was a lack of insight in net companies and the pricing of their services. Therefore, the focus of this study has been on the insight of the net companies. There is also a law in the electricity act that states that electricity producing units with an effect of less than 1500 kW is not obligated to pay tariffs. How actors in the wind power business experience this rule and the consequence of it is also examined in this study. The method to implement this is to do qualitative interviews with stakeholders in the wind power industry in order to get their opinion on this matter. Theories of monopoly, principal-agent, and asymmetric information have been used to frame this problem. Conclusions of the study are that wind power companies experience that they are "powerless" towards net companies and that they do not have as much insight in the net companies' pricing strategies as they desire. The consequence of this is a suspiciousness and anxiety that the pricing is not fair. The study also shows that a clearer set of laws concerning pricing of net connections and tariffs is requested. The study has also shown ideas and solutions for how the wind power companies can lower their degree of dependence and increase the insight in net connections and tariffs.I Sverige växer vindkraften. Den utgör dock fortfarande en liten del av den totala elproduktionen, ca 0, 7 %. För att skapa goda förutsättningar och underlätta etableringen av vindkraft i Sverige har regeringen vidtagit vissa åtgärder. Detta för att uppnå det statliga mål att det ska finnas planmässiga förutsättningar för en utbyggnad av vindkraft med 10 TWh till år 2015 jämfört med nivån för 2002. Den svenska elmarknaden avreglerades 1996 och konkurrens infördes på produktion och handel med el. Nätverksamheten fortsatte dock att vara ett monopol då det ansågs för dyrt och inte heller rationellt att dra nya elledningar. Ett vindkraftsföretag är beroende av nätbolagens tjänster för att kunna föra ut den producerade elen på elnätet. Under förstudier till detta arbete framkom det att vissa vindkraftsföretag upplever anslutningsprocessen som besvärlig och regelverket kring detta som problematiskt. Syftet med denna studie är att bidra med input till en statlig utredning som ska undersöka huruvida det nuvarande regelverket skapar hinder för en storskalig utveckling och utbyggnad av förnybar elproduktion. Detta arbete har undersökt hur aktörer inom vindkraftsbranschen upplever regelverket kring nätanslutning och tariffer och vad det ger för konsekvenser. Det framkom på tidigt stadium i detta arbete att vindkraftsföretag upplever att det är brist på insyn i nätbolagens prissättning, så fokus har legat på detta. Det finns även en regel i ellagen som säger att elkraftverk med en effekt på mindre är 1500 kW inte ska betala tariffer. Hur aktörer ser på denna regel och konsekvenser av den har undersökts. Metoden för att genomföra detta har varit att göra kvalitativa intervjuer med vindkraftsföretag och nätföretag för att ta del av deras åsikter. Teorier om monopol, resursberoende, principalagent, och asymmetrisk information har använts för att rama in problemet. Slutsatser av studien är att vindkraftsföretag upplever att de är maktlösa gentemot nätföretag och att de inte har så mycket insyn i nätföretagens prissättning som de skulle vilja ha. Konsekvenser av detta blir en misstänksamhet och oro för att prissättningen inte är riktig. Studien visar att ett tydligare regelverk kring prissättning av nätanslutningar och tariffer efterfrågas. I studien har de även framkommit idéer och lösningar på hur vindkraftsföretagen kan minska deras beroende mot nätföretagen och skapa en transparens kring nätanslutningar och tariffer

Innovationsinseln in korporatistischen Arrangements: Public Private Partnerships im Feld sozialer Dienstleistungen

Öffentlich-private Kooperationen im Sozialen Sektor sind ein altes und neues Phänomen. Der vorliegende Text gibt in dieser Spannung einen Überblick über die Entwicklung von Public Private Partnership in diesem Feld. Die Arena der personenbezogenen sozialen Dienstleistungen zeigt sich nach den Bereichen der Stadt- und Regionalentwicklung und der technischen Infrastrukturen als jüngster Sektor in Deutschland, in dem Public Private Partnerships (PPP) Bedeutung erlangen. Allerdings entstehen diese neuen Kooperationsformen innerhalb eines dichten Netzes korporatistischer Arrangements von staatlichen Institutionen und Dritt-Sektor- Organisationen. Zum jetzigen Zeitpunkt sind PPP lediglich vereinzelte neue Organisationsformen in diesem Feld. Aus der Dynamik der Interaktionsbeziehungen und Ressourcenkopplungen innerhalb dieser PPP können jedoch spezifische Qualitätsverbesserungen hervor gehen, die wir vor allem in der Integration von Aufgaben zu neuen lebenslagenorientierten Angeboten und in der Entwicklung höherer Dienstleistungsstandards sehen. -- In the Social Service Sector, public private cooperation is an old, but also a new phenomenon. The present study gives an overview of the development of public private partnerships in this area. The most recent sector in Germany, after those of urban development and technical infrastructure, in which public private partnerships (PPP) become relevant, is the arena of person-related social services. Such new forms of cooperation develop, however, within a dense network of corporatist arrangements between national institutions and Third Sector service organizations. To date, PPPs have only become sporadic new organizational forms in this field. Nevertheless, specific improvements in quality might emerge from the dynamics of inter-organisational relations and the linkage of resources within PPPs which, eventually, should lead to an integration of services which better consider specific personal circumstances and to the development of higher standards of social service.

Restrukturierung der kommunalen Dienstleistungsproduktion: Innovationsfähigkeit deutscher Kommunen in internationaler Perspektive

In diesem Beitrag geht es um die Restrukturierung des Produktionsprozesses öffentlicher Dienstleistungen am Beispiel der Kommunalverwaltung, die gegenwärtig unter der Bezeichnung "New Public Management" in allen OECD-Staaten zu beobachten ist. Skizziert werden die konvergenten ausländischen Entwicklungen zentraler Elemente der Reform der Dienstleistungsproduktion mit ihren drei Phasen des Umbaus der Aufbau- und Ablaufstrukturen und der Steuerungssysteme, der Verbesserung der Leistungsprozesse und -produkte sowie der Ansätze grundlegenderer Restrukturierungen ("reengineering"). Als dynamisierende Elemente des Wandels werden speziell neue Formen des Wettbewerbs sowie der Integration der Kunden-/ Bürgerperspektive in den Blick genommen. Ausgehend von dem bis zu Beginn der 90er Jahre vorherrschenden deutschen Modell der kommunalen Leistungsproduktion wird der Frage nach den förderlichen und hemmenden Basisinstitutionen, Akteurskonstellationen und vorgängigen Reformerfahrungen für den begonnenen Prozeß der aufholenden Modernisierung hierzulande nachgegangen. Als besondere Potentiale sind das Institutionengefüge mit den Elementen breiter dezentraler Aufgabenverantwortung und Selbstverantwortung sowie Anbieterpluralität und mindestens punktuelle Reformerfahrungen auf den Gebieten direkter Bürgerbeteiligung und kooperativer Leistungsgestaltung hervorzuheben. Das komplexe und traditionell konsensorientierte Akteursnetzwerk in Deutschland behindert dagegen eher die Bildung durchsetzungsfähiger Reformkoalitionen. (HH

3D optomechanical metamaterials

Ideally, many materials should have a “knob” that allows for changing its properties at will, including the possibility to flip the sign of its behavior. This “knob” could be used to continuously tune the properties or in the sense of a digital switch. Such extreme level of stimulus–responsiveness has come into reach with recently increased possibilities of manufacturing complex rationally designed artificial materials called metamaterials on the micrometer scale. Here, we present mechanical metamaterials composed of liquid–crystal elastomers, whose director field is arranged into a designed complex three-dimensional (3D) pattern during the 3D laser printing process. External light from a blue LED, with intensities in the range of 10–30 W/cm$^{2}$, serves as the stimulus. In the first example, we repeatedly flip the sign of the Poisson’s ratio of an achiral architecture within classical elasticity. In the second example, we flip the sign of the twist per strain in a chiral metamaterial beyond classical elasticity. The presented examples overcome major limitations in responsive mechanical metamaterials and we foresee many possible three-dimensional responsive micro-architectures manufactured along these lines

Innovationsinseln in korporatistischen Arrangements: Public Private Partnerships im Feld sozialer Dienstleistungen

"Öffentlich-private Kooperationen im Sozialen Sektor sind ein altes und neues Phänomen. Der vorliegende Text gibt in dieser Spannung einen Überblick über die Entwicklung von Public Private Partnership in diesem Feld. Die Arena der personenbezogenen sozialen Dienstleistungen zeigt sich nach den Bereichen der Stadt- und Regionalentwicklung und der technischen Infrastrukturen als jüngster Sektor in Deutschland, in dem Public Private Partnerships (PPP) Bedeutung erlangen. Allerdings entstehen diese neuen Kooperationsformen innerhalb eines dichten Netzes korporatistischer Arrangements von staatlichen Institutionen und Dritt-Sektor- Organisationen. Zum jetzigen Zeitpunkt sind PPP lediglich vereinzelte neue Organisationsformen in diesem Feld. Aus der Dynamik der Interaktionsbeziehungen und Ressourcenkopplungen innerhalb dieser PPP können jedoch spezifische Qualitätsverbesserungen hervor gehen, die wir vor allem in der Integration von Aufgaben zu neuen lebenslagenorientierten Angeboten und in der Entwicklung höherer Dienstleistungsstandards sehen." (Autorenreferat)"In the Social Service Sector, public private cooperation is an old, but also a new phenomenon. The present study gives an overview of the development of public private partnerships in this area. The most recent sector in Germany, after those of urban development and technical infrastructure, in which public private partnerships (PPP) become relevant, is the arena of person-related social services. Such new forms of cooperation develop, however, within a dense network of corporatist arrangements between national institutions and Third Sector service organizations. To date, PPPs have only become sporadic new organizational forms in this field. Nevertheless, specific improvements in quality might emerge from the dynamics of inter-organisational relations and the linkage of resources within PPPs which, eventually, should lead to an integration of services which better consider specific personal circumstances and to the development of higher standards of social service." (author's abstract

Characterization of fast-growing foams in bottling processes by endoscopic imaging and convolutional neural networks

Regardless of whether the occurrence of foams in industrial processes is desirable or not, the knowledge about the characteristics of their formation and morphology is crucial. This study addresses the measuring of characteristics in foam and the trailing bubbly liquid that result from air bubble entrainment by a plunging jet in the environment of industry-like bottling process es of non-carbonated beverages. Typically encountered during the bottling of fruit juices, this process configuration is characterized by very fast filling speeds with high dynamic system parameter changes. Especially in multiphase systems with a sensitive disperse phase like gas bubbles, the task of its measurement turns out to be difficult. The aim of the study is to develop and employ an image processing capability in real geometries under realistic industrial conditions, e.g. as opposed to a narrow measurement chamber. Therefore, a typically sized test bottle was only slightly modified to adapt an endoscopic measurement technique and to acquire image data in a minimally invasive way. Two convolutional neural networks (CNNs) were employed to analyze irregular non-overlapping bubbles and circular overlapping bubbles. CNNs provide a robust object recognition for varying image qualities and therefore can cover a broad range of process conditions at the cost of a time-consuming training process. The obtained single bubble and population measurements allow approximation, correlation and interpretation of the bubble size and shape distributions within the foam and in the bubbly liquid. The classification of the measured foam morphologies and the influence of operating conditions are presented. The applicability to the described test case as an industrial multiphase process reveals high potential for a huge field of operations for particle size and shape measurement by the introduced method

A Facile Approach for 4D Microprinting of Multi‐Photoresponsive Actuators

For microscale 4D photoresponsive actuators, light is crucial in two ways. First, the underlying additive manufacturing techniques rely on photopolymerization processes triggered by the absorption of light. Second, the absorption of light serves as the actuation stimulus. The two absorptions can be conflicting. While the microstructure requires strong absorption at the actuation wavelength(s), this absorption should not interfere with that of the manufacturing process. Herein, a simple strategy is proposed to overcome these limitations and allow for the fabrication of multi-photoresponsive 3D microstructures that can be actuated at different wavelengths of light. Two-photon 3D laser printing is selected as the fabrication technique and liquid crystalline (LC) elastomers as the functional materials. In a first step, 3D microstructures are fabricated using an aligned LC ink formulation. Thereafter, up to five different dyes exhibiting absorptions that extend over the entire visible regime (400–700 nm) are successfully incorporated into the LC microstructures by an exchange process enabling a programmable actuation by irradiating with the suitable wavelength. Furthermore, by combining dyes exhibiting orthogonal absorptions, wavelength-selective actuations are demonstrated