Refine
Document Type
- Journal article (1239)
- Conference proceeding (1035)
- Book chapter (381)
- Book (223)
- Doctoral Thesis (54)
- Working Paper (37)
- Anthology (32)
- Report (25)
- Patent / Standard / Guidelines (24)
- Issue of a journal (19)
Is part of the Bibliography
- yes (3078)
Institute
- ESB Business School (1102)
- Informatik (871)
- Technik (508)
- Life Sciences (343)
- Texoversum (219)
- Zentrale Einrichtungen (16)
Publisher
- Springer (346)
- IEEE (250)
- Elsevier (219)
- Hochschule Reutlingen (186)
- MDPI (98)
- Springer Gabler (79)
- Gesellschaft für Informatik (66)
- Universitätsbibliothek Tübingen (59)
- Wiley (54)
- ACM (40)
Contemporary public enterprises differ from their forebears. Today, they are more similar to private enterprises, receiving far more attention than previously, when privatization processes all over the world were in the spotlight. Furthermore, the broad research stream of entrepreneurship has so far neglected the consideration of public enterprises. To set a future research agenda, the author examines the dispersed literature using an integrative and organizing framework to identify major topics and research findings. This paper reviews articles that investigate the entrepreneurship in contemporary public enterprises. Despite the growing scholarly interest globally, this systematic literature review indicates there is no more than a loose connection between the literature streams of public entrepreneurship and corporate entrepreneurship. Specifically, the review shows that the multidimensional concept of entrepreneurial orientation has thus far been ignored, although autonomy plays a significant role in the literature review, namely in the context of the interference of the public owner. It also reveals other essential research gaps, such as the development of a modern theory of public enterprises. The linked research stream of public-sector corporate entrepreneurship offers a broad area of scholarly research and should encourage further investigation.
Background aims: In vitro engineered adipose tissue is in great demand to treat lost or damaged soft tissue or to screen for new drugs, among other applications.However, today most attempts depend on the use of animal-derived sera. To pave the way for the application of adipose tissue-engineered
products in clinical trials or as reliable and robust in vitro test systems, sera should be completely excluded from the production process. In this study, we aimed to develop an in vitro adipose tissue model in the absence of sera and maintain its function long-term.
Methods: Human adipose tissue-derived stem cells were expanded and characterized in a xeno- and serum-free environment. Adipogenic differentiation was induced using a completely defined medium. Developed adipocytes were maintained in a completely defined maturation medium for additional 28 days. In addition to cell-viability and adherence, adipocyte-specific markers such as perilipin A expression of leptin release were evaluated.
Results: The defined differentiation medium enhanced cell adherence and lipid
accumulation at a significant level compared with the corresponding negative control. The defined maturation medium also significantly supported cell adherence and functional adipocyte maturation during the long-term culture period.
Conclusions: The process described here enables functional adipocyte generation and maintenance without the addition fo unknown or unimal-derived constituents, achieving an important milestone in the introduction of adipose tissue engineered products into clinical trials or in vitro screening.
Bone remodeling can be mimicked in vitro by co-culture models. Based on bone cells, such co-cultures help to study synergistic morphological changes and the impact of materials and applied substances. Hence, we examined the formation of osteoclasts on bovine bone materials to prove the bone resorption functionality of the osteoclasts in three different co-culture set-ups using human monocytes (hMCs) and (I) human mesenchymal stem cells (hMSCs), (II) osteogenic differentiated hMSCs (hOBs), and (III) hOBs in addition of soluble monocyte-colony stimulating factor (M CSF) and cytokine receptor activator of NFkB ligand (RANKL).We detected osteoclast-specific actin morphology, as well as the expression of cathepsin K and CD51/61 in single cells in set-up II and in numerous cells in set-up III. Resorption pits on bone material as characteristic proof of functional osteoclasts were not found in set-up I and II, but we detected such resorption pits in set–up III. We conclude in co culture models without M-CSF and RANKL that monocytes can differentiate into osteoclasts that show the characteristic actin structures and protein expression. However, to receive functional bone resorbing osteoclasts in vitro, the addition of M-CSF and RANKL is needed. Moreover, we suggest the use of bone or bone-like materials for future studies evaluating osteoclastogenesis.
Theory predicts that market‐timing activities bias Jensen's alpha (JA). However, empirical studies have failed to find consistent evidence of this bias. We tackle this puzzle in a nested model analysis and show that the bias contains an exogenous market component that is unrelated to market‐timing skill. In a comprehensive empirical analysis of US mutual funds, we find that the timing‐induced bias in JA is mainly driven by this market component, which is uncorrelated with measured timing activities. Measures of total performance that allow for timing activities are virtually identical to JA, even if timing activities are present in the evaluated fund. Hence, we conclude that JA is a sufficient measure of total performance.
Annotations of subject IDs in images are very important as ground truth for face recognition applications and news retrieval systems. Face naming is becoming a significant research topic in news image indexing applications. By exploiting the uniqueness of name, face naming is transformed to the problem of multiple instance learning (MIL) with exclusive constraint, namely the eMIL problem. First, the positive bags and the negative bags are automatically annotated by a hybrid recurrent convolutional neural network and a distributed affinity propagation cluster. Next, positive instance selection and updating are used to reduce the influence of false-positive bag and to improve the performance. Finally, max exclusive density and iterative Max-ED algorithms are proposed to solve the eMIL problem. The experimental results show that the proposed algorithms achieve a significant improvement over other algorithms.
Nowadays robust, energy-efficient multisensor microsystems often come with heavily restricted power budgets and the characteristic of remaining in certain states for a longer period of time. During this time frame there is no continuous clock signal required which gives the opportunity to suspend the clock until a new transition is requested. In this paper, we present a new topology for on-demand locally clocked finite state machines. The architecture combines a local adaptive clocking approach with synchronous and asynchronous components forming a quasi synchronous system. Using adaptive and local clocking comes with the advantages of reducing the power consumption while saving design effort when no global clock tree is needed. Combining synchronous and asynchronous components is beneficial compared to previous fully asynchronous approaches concerning the design restrictions. The developed topology is verified by the implementation and simulation of a temperature-ADC sensor system realized in a 180 nm process.
We present a compact battery charger topology for weight and cost sensitive applications with an average output current of 9A targeted for 36V batteries commonly found in electric bicycles. Instead of using a conventional boost converter with large DC-link capacitors, we accomplish PFC-functionality by shaping the charging current into a sin²-shape. In addition, a novel control scheme without input-current sensing is introduced. A-priori knowledge is used to implement a feed-forward control in combination with a closed-loop output current control to maintain the target current. The use of a full-bridge/half bridge LLC converter enables operation in a wide input-voltage range.
A fully featured prototype has been built with a peak output power of 1050W. An average output power of 400W was measured, resulting in a power density of 1.8 kW/dm³. At 9A charging current, a power factor of 0.96 was measured and the efficiency exceeds 93% on average with passive rectification.
The impact of pulse charging has been evaluated on a 400Wh battery which was charged with the proposed converter as well as CC-CV-charging for reference. Both charging schemes show similar battery surface temperatures.
Manufacturing has to adapt to changing situations in order to stay competitive.It demands a flexible and easy-to-use integration of production equipment and ICT systems. The contribution of this paper is the presentation of the implementation of the Manufacturing Integration Assistant (MIALinx). The integration steps range from integrating sensors over collecting and rule-based processing of sensor information to the execution of required actions. Furthermore, we describe the implementation of MIALinx by commissioning it in a manufacturing environment to retrofit legacy machines for Industrie 4.0. Finally, we validate the suitability of our approach by applying our solution in a medium-size company.
Defining the antecedents of experience co-creation as applied to alternative consumption models
(2019)
Purpose – The purpose of this paper is to propose a conceptual framework of experience co-creation that captures the multi-dimensionality of this construct, as well as a research process for defining of the antecedents of experience co-creation.
Design/methodology/approach – The framework of experience co-creation was conceptualized by means of a literature review. Subsequently, this framework was used as the conceptual basis for a qualitative content analysis of 66 empirical papers investigating alternative consumption models (ACMs), such as renting, remanufacturing, and second-hand models.
Findings – The qualitative content analysis resulted in 12 categories related to the consumer and 9 related to the ACM offerings that represent the antecedents of experience co-creation. These categories provide evidence that, to a large extent, the developed conceptual framework allows one to capture the multi-dimensionality of the experience co-creation construct.
Research limitations/implications – This study underscores the understanding of experience co-creation as a function of the characteristics of the offering – which are, in turn, a function of the consumers’ motives as determined by their lifeworlds – as well as to service design as an iterative approach to finding, creating and refining service offerings.
Practical implications – The investigation of the antecedents of experience co-creation can enable service providers to determine significant consumer market conditions for forecasting the suitability and viability of their offerings and to adjust their service designs accordingly.
Originality/value – This paper provides a step toward the operationalization of the dimension-related experience co creation construct and presents an approach to defining the antecedents of experience co-creation by considering different research perspectives that can enhance service design research.
Nachhaltige Managementmodelle sind auf Erfüllung der Triple Bottom Line ausgerichtet: Unternehmen adressieren Energie- und Co2-Effizienz (ökologisch), Arbeitsschutz oder Arbeitslosenquoten (sozial) sowie mögliche Wachstumspotenziale, die durch Nachhaltigkeit zu erreichen sind, um das eigene Überleben des Unternehmens am Markt zu sichern (ökonomisch). Daneben stehen die 17 Sustainable Development Goals (SDGs), die bis 2030 als Leitlinie nachhaltigen Wirtschaftens weltweit gelten und in nationale Gesetzgebung überführt wurden. Dieser Beitrag entwickelt ein Managementmodell, das Unternehmen dabei unterstützt, relevante SDGs zu identifizieren und Handlungsempfehlungen abzuleiten. Aufbauend auf einer nachhaltigen Supply Chain ordnet das Modell die SDGs den Dimensionen der Triple Bottom Line zu, um kurz eine Checkliste möglicher zu berücksichtigender Nachhaltigkeitsmaßnahmen im Kontext des Behaviour Change Modells zu erarbeiten. Zurückgreifend auf die Empfehlungen der Vereinten Nationen wird ein nachhaltiger Managementansatz eingeführt, der Unternehmen dazu befähigt, Governance, Transparenz und Engagement in ihrer Supply Chain zu implementieren.
This paper introduces a highly scalable heteromodular origami art technique for constructing 3D framework structures using elementary struts and connectors folded from uncut sheets of standard A4 office paper. The presented technique, named ZEBRA, allows the design of meter-scale architectural objects, such as truss bridges and towers, which are capable of bearing substantial mechanical loads. Moving parts, ranging from simple levers to complete multi-bar linkages, can be integrated into static frameworks using a set of kinematic extensions. An overview is given of how the ZEBRA system can be used to teach university students various theoretical and practical aspects of the engineering sciences in an entertaining and hands-on way.
Die Mesago Messe Frankfurt als Veranstalter der Formnext 2018 haben von Prof. Dr.-Ing. Steffen Ritter von der Hochschule Reutlingen eine anschauliche Übersicht erstellen lassen, welche die Vielfalt der unterschiedlichen Verfahren zur additiven Fertigung verständlich erklärt. Die kleine, zweisprachige Broschüre mit dem Titel „AM Field Guide“ bietet auf 12 Seiten strukturierte Vergleichsdarstellungen von insgesamt 19 gängigen 3-D-Druck Technologien für Kunststoffe, Metalle sowie andere Werkstoffe und dazu noch einen Überblick über die Phasen und Prozessschritte in Projekten für Bauteile, die additiv hergestellt werden.
Mehr denn je zeigt ein Blick auf die aktuellen gesellschaftlichen Debatten, wie wichtig angewandte Forschung ist, denn sie liefert fundierte Fakten und Erkenntnisse für den politischen Diskurs. So verstehen wir unseren Auftrag zur Forschung: Wir helfen Gesellschaft und Wirtschaft, Lösungen für die drängenden Fragen unserer Zeit zu entwickeln. Wie wir das machen? Auf den folgenden Seiten bekommen Sie einen kleinen Einblick in die aktuellen Forschungsprojekte an der Hochschule. Sie werden feststellen, dass diesmal ganz der Mensch im Mittelpunkt steht. Gute Forschung ist auch die Grundlage für die Ausbildung hochqualifizierter Absolventinnen und Absolventen, die die Unternehmen so dringend brauchen, um nachhaltig wettbewerbsfähig zu bleiben. Wir machen die Studierenden fit für die „Welt da draußen“ – mit besonderen Laborprojekten (Seite 26), mit spannenden Promotionsarbeiten (Seite 10) und Unterstützung von Ausgründungen (Seite 18).
Lithographical hotspot (LH) detection using deep learning (DL) has received much attention in the recent years. It happens mainly due to the facts the DL approach leads to a better accuracy over the traditional, state-of-the-art programming approaches. The purpose of ths study is to compare existing data augmentation (DA) techniques for the integrated circuit (IC) mask data using DL methods. DA is a method which refers to the process of creating new samples similar to the training set, thereby helping to reduce the gap between classes as well as improving the performance of the DL system. Experimental results suggest that the DA methods increase overall DL models performance for the hotspot detection tasks.
Background. The application of lean management is standard in many companies all over the world. It is used to continuously optimise existing production processes and to reduce the complexity of administrative processes. Unfortunately, in higher education, the awareness of lean management as a highly effective methodology is quite low.
Research aims. The research aim is to show how the lean strategy can be applied in university environments. Finally, this paper addresses the question why it is so difficult to implement lean in a university environment and how an institution of higher education can move forward towards becoming a lean university.
Methodology. Based on a literature review, five key lean principles are presented and examples of their implementation are discussed using short case studies from our own institution. We also compare our findings with those in the literature.
Key findings. Lean offers the chance to improve the management of higher education institutions. This requires a commitment on the part of the university top management aiming at convincing all stakeholders that a culture of lean helps the institution to be able to adapt to the rapidly changing environment of higher education.
Hauptziel des Projektes war zum einen die Entwicklung einer validen Testmethode auf Grundlage vorliegender Normen, welche die in der betrieblichen Praxis auftretende Degradation abreinigbarer Filtermedien (hohe Temperaturen, aggressive chemische Atmosphären) praxisnah abbilden kann. Die Methode sollte auch die mechanische Alterung der Medien durch Staubbeaufschlagung sowie Abreinigungs Druckstöße berücksichtigen (DIN ISO 11057). Innerhalb des Projektes konnten umfangreiche Praxiserfahrungen mit der Inbetriebnahme und dem Betrieb einer schadgasbeaufschlagten, temperierbaren Testkammer zur chemischen Alterung von Filtermedien auf Grundlage der Vorgaben der DIN EN ISO 16891 gewonnen werden. Sollen vergleichbare Prüfdaten für mehrere Proben verlässlich ermittelt werden, sind bei den Untersuchungen demnach umfangreiche Randbedingungen zu beachten. Insbesondere zeigten die Untersuchungen den hohen technischen Aufwand zur Durchführung der Filtertests auf, welche nicht zuletzt auch aufgrund der erforderlichen Sicherheitstechnik und langen Untersuchungsdauer eine Umsetzung insbesondere bei KMU aus wirtschaftlichen Gründen erschwert ist. Es konnte weiter dargestellt werden, dass die Kombination von chemisch-thermischer und mechanisch(-thermischer) Alterung durch den Einsatz verschiedener Prüfeinrichtungen grundsätzlich umsetzbar ist. Die im Rahmen des Vorhabens entwickelte Testmethode einer chemischen Alterung der Filtermatrices durch Gasphasenexposition in einer Druckkammer ermöglicht kürzere Beanspruchungszeiträume bei reduziertem zu behandelnden Schadgasanfall und kann damit den wirtschaftlichen Betrieb eines entsprechenden Prüfstandes ermöglichen. Kombiniert mit der externen mechanischen Alterung durch Staubbeaufschlagung und Möglichkeit der parallelen Temperaturaufprägung gem. EN ISO 16891 auf mehrere Filtermedien-Proben lässt sich das thermisch, chemisch und mechanisch induzierte Degradationsverhalten von Filtermedien ggf. realitätsnah und mit wirtschaftlich vertretbarem Aufwand in eine Prüfvorschrift überführen. Entsprechende Validierungsarbeiten sind Bestandteil eines aktuell gestarteten Folgeprojektes. Das zweite Hauptziel des Projektes war es Ausrüstungen zu entwickeln, die zu einer verbesserten Beständigkeit gegenüber aggressiven Komponenten führen. Die Ergebnisse zeigten, dass mit dem Sol-Gelverfahren mechanisch stabile Beschichtungen auf Faservlies dauerhaft aufgetragen werden konnten, welche insbesondere die chemisch induzierte Degradation von Aramiden reduzieren können. Bei Aramiden handelt es sich um relativ teure Hochleistungsmaterialien, von welchen bekannt ist, dass ihre Beständigkeit sowohl gegen über UV-Strahlung als auch unterschiedlichen Schadgasen gering ist. Daher stellen die Beständigkeit der Materialien verbessernde Ausrüstungen eine wichtige Entwicklung für Unternehmen dar, um auf diese Weise beständigere Aramid-basierte Produkte zu erhalten. Als besonders geeignet stellten sich dabei Fluorcarbonausrüstungen, organisch-anorganische Hybride auf Basis von GPTMS und Zirkonium-haltige Ausrüstungen heraus.
A transaction is a demarcated sequence of application operations, for which the following properties are guaranteed by the underlying transaction processing system (TPS): atomicity, consistency, isolation, and durability (ACID). Transactions are therefore a general abstraction, provided by TPS that simplifies application development by relieving transactional applications from the burden of concurrency and failure handling. Apart from the ACID properties, a TPS must guarantee high and robust performance (high transactional throughput and low response times), high reliability (no data loss, ability to recover last consistent state, fault tolerance), and high availability (infrequent outages, short recovery times).
The architectures and workhorse algorithms of a high-performance TPS are built around the properties of the underlying hardware. The introduction of nonvolatile memories (NVM) as novel storage technology opens an entire new problem space, with the need to revise aspects such as the virtual memory hierarchy, storage management and data placement, access paths, and indexing. NVM are also referred to as storage-class memory (SCM).
Active storage
(2018)
In brief, Active Storage refers to an architectural hardware and software paradigm, based on collocation storage and compute units. Ideally, it will allow to execute application-defined data ... within the physical data storage. Thus Active Storage seeks to minimize expensive data movement, improving performance, scalability, and resource efficiency. The effective use of Active Storage mandates new architectures, algorithms, interfaces, and development toolchains.