Efficient Solution of Large-Scale Algebraic Riccati Equations Associated with Index-2 DAEs via the Inexact Low-Rank Newton-ADI Method

This paper extends the algorithm of Benner, Heinkenschloss, Saak, and Weichelt: An inexact low-rank Newton-ADI method for large-scale algebraic Riccati equations, Applied Numerical Mathematics Vol.~108 (2016), pp.~125--142, doi:10.1016/j.apnum.2016.05.006 to Riccati equations associated with Hessenberg index-2 Differential Algebratic Equation (DAE) systems. Such DAE systems arise, e.g., from semi-discretized, linearized (around steady state) Navier-Stokes equations. The solution of the associated Riccati equation is important, e.g., to compute feedback laws that stabilize the Navier-Stokes equations. Challenges in the numerical solution of the Riccati equation arise from the large-scale of the underlying systems and the algebraic constraint in the DAE system. These challenges are met by a careful extension of the inexact low-rank Newton-ADI method to the case of DAE systems. A main ingredient in the extension to the DAE case is the projection onto the manifold described by the algebraic constraints. In the algorithm, the equations are never explicitly projected, but the projection is only applied as needed. Numerical experience indicates that the algorithmic choices for the control of inexactness and line-search can help avoid subproblems with matrices that are only marginally stable. The performance of the algorithm is illustrated on a large-scale Riccati equation associated with the stabilization of Navier-Stokes flow around a cylinder.Comment: 21 pages, 2 figures, 4 table

Neuartige Methoden diffraktiver Mask Aligner Lithografie zur flexiblen Erzeugung mikrooptischer Strukturen

Die Mask Aligner Lithografie bietet einfache und adaptierbare Herstellungsmöglichkeiten zur Erzeugung einer Primärstruktur für ein breites Spektrum an Elementen, auch speziell für die Mikrooptik. Für den lithografischen Prozess stellen die Photomaske sowie deren Beleuchtung signifikante und einflussreiche Parameter für die Strukturerzeugung dar. Diese Bedeutung konnte im Rahmen dieser Arbeit anhand verschiedener Beispiele unterstrichen und genutzt werden. In dieser Arbeit wurde neben der Entwicklung neuartiger Photomasken-Technologien ein neues Beleuchtungssystem eingeführt, bei dem die konventionell genutzte Beleuchtungsquelle einer Quecksilberdampflampe gegen einen Festkörperlaser getauscht wurde. Ein wesentlicher Vorteil des neuen Beleuchtungssystems mit einem Laser als Beleuchtungsquelle besteht in einer konstanten Bestrahlungsstärke unabhängig vom Winkelspektrum der Photomaskenbeleuchtung, wodurch auch für kleine Winkelspektren kurze Belichtungszeiten möglich sind. Darüber hinaus wurde Erzeugung mikrooptischer Strukturen optimiert und neue Belichtungskonzepte z.B. zur Herstellung kontinuierlicher Oberflächenprofile oder aperiodischer Strukturen erarbeitet. Eine neu entwickelte Technologie für verschiebbare Photomasken ermöglicht Mehrfachbelichtungen, um beispielsweise kontinuierliche Oberflächenprofile herzustellen oder die Dichte binärer Strukturen zu erhöhen. Eine weitere Möglichkeit, kontinuierliche Strukturen herzustellen, bieten optimierte Photomasken. So konnte gezeigt werden, dass mittels mehrstufiger Phasenmaske die Geometrie einer Blazestruktur angepasst und eine senkrechte Rückflanke generiert werden kann. Weiterhin wurden neue Photomaskendesigns basierend auf einer kombinierten Amplituden- und Phasenmodulation entwickelt. So konnte eine erfolgreiche Auflösungssteigerung der Schattenwurflithografie für aperiodische Strukturen mittels einer mehrstufigen Photomaske realisiert werden. Darüber hinaus wurde ein neuartiges Konzept einer doppelseitig strukturierten Photomaske entwickelt und am Beispiel der Strukturierung dicker Lacke getestet

Mergers and Acquisitions - Elaborating Factors for Enterprise Interoperability in an ERP context

In this paper, the authors discussed Enterprise Interoperability (EI) in Mergers and Acquisitions (M&A) transactions focusing on ERP systems. Essential connections to practice are drawn through a discussion of use cases with experts from the fields of M&A, IT, and ERP. The research questions are defined as: What are the core influencing factors determining interoperability profiles? What will the future look like regarding the ERP dimension? Based on eleven experts and qualitative content analysis, relevant findings on EI implementation scenarios are extracted. There are different approaches to achieve Enterprise Interoperability, depending on the context of the M&A transaction. Finally, the crucial decision factors are given in the findings and show the future development of ERP systems integrations. Current results suggest that fast and easy EI is a critical requirement to meet the increasing need for flexibility and ERP systems are at the core of these developments

A Historical Geography of the Paper Industry in the Wisconsin River Valley

The paper industry, which has played a vital social, economic, and cultural role throughout the Wisconsin River valley, has been under pressure in recent decades. Technology has lowered demand for paper and Asian producers are now competing with North American mills. As a result, many mills throughout the valley have been closed or purchased by nonlocal corporations. Such economic disruption is not new to this region. Indeed, paper manufacture itself emerged when local businessmen diversified their investments following the decline of the timber industry. New technology in the late nineteenth century enabled paper to be made from wood pulp, rather than rags. The area’s scrub trees, bypassed by earlier loggers, produced quality pulp, and the river provided a reliable power source for new factories. By the early decades of the twentieth century, a chain of paper mills dotted the banks of the Wisconsin River. The paper industry helped to revive struggling sawmill communities in the region and, in some cases, created completely new settlements. Paper company executives, in fact, served as both employers and civic leaders. Operating under the principles of “welfare capitalism,” these leaders provided employees good wages and made generous gifts to local communities. This culture persisted for decades, but ended abruptly when local mills were sold. Using a variety of sources including, newspapers, maps, business records, and interviews, this dissertation examines the paper industry’s impact on three communities in the Wisconsin River valley: Nekoosa, Port Edwards, and Wisconsin Rapids. It examines factors that made the region attractive to paper manufacturers and discusses the entrepreneurial decisions that led to the creation of successful mills in each city. Later chapters investigate the industry’s impact on the material landscape of the three communities and how these places are coping with paper’s recent decline

A software-framework for the development of business application systems based on business process models

Die Geschäftsprozessmodellierung hat sich in der Praxis als Grundlage für die Ableitung fachlicher Anforderungen an betriebliche Anwendungssysteme weitgehend etabliert. Die anschließende Übertragung der fachlichen Modelle auf eine software-technische Implementierungsplattform bedeutet hingegen häufig einen methodischen Bruch und ist daher sehr aufwändig sowie komplex. Eine software-technische Implementierungsplattform, deren Konzepte sich an den Fachkonzepten der Geschäftsprozessmodellierung orientieren, kann diesen Übergang vereinfachen und die Systementwicklungsaufgabe hinsichtlich Aufwand und Komplexität deutlich verringern. Die vorliegende Arbeit beschreibt die Konzeption und Realisierung eines Software-Frameworks als flexible Basismaschine für die Entwicklung betrieblicher Anwendungssysteme auf Basis der SOM-Methodik. Das Framework bietet ausgehend von den fachlichen Modellen des Anwendungssystems anwendungsneutrale Software-Komponenten zu dessen vollständiger software-technischer Abbildung.Business process modeling is in practice an established way to deduct business and functional requirements for business application systems. The subsequent mapping of such business models onto a software-technical implementation platform usually implies a methodic break and is in consequence both costly and complex. A software-technical implementation platform, in contrast, whose concepts are aligned with the functional concepts of business process modeling, can simplify this transition and significantly reduce the task of application development regarding effort and complexity. This thesis describes the conception and implementation of a software-framework as a flexible basis machine for the development of business application systems based on the SOM-methodology. Based on the methodology‘s functional models of an application system the framework offers application-neutral software-components for a comprehensive mapping of the model and implementation of the application

Augmented Reality Farm MAPPER Development: Lessons Learned from an App Designed to Improve Rural Emergency Response

Fire departments have right-of-entry to most commercial industrial sites and preemptively map them to identify the onsite resources and hazards they need to promptly and safely respond to an emergency event. This is not the case for private farms. Emergency responders are blind to resources and hazards prior to arrival and must spend critical minutes locating them during an emergency response at a farm location. The original 2013 Farm Mapping to Assist, Protect and Prepare Emergency Responders (Farm MAPPER) project was undertaken to develop a method to give emergency responders an up-to-date view of on-farm hazard information to safely and efficiently conduct emergency response activities on private agricultural operations. In 2017, an augmented reality version of Farm MAPPER was developed to combine the technological advantages of geographic information system-based data points with a heads-up display and graphical overlay of superimposed hazard imagery and informative icons. The development and testing of this iOS- and Android-ready prototype uncovered lessons learned applicable to other mobilebased apps targeting farmers, ranchers, and rural populations faced with limited or inconsistent mobile internet connectivity