Essays on empirical finance in times of crises : fractional integration, structural breaks, and explosiveness

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Embedded Program Annotations for WCET Analysis

We present __builtin_ais_annot(), a user-friendly, versatile way to transfer annotations (also known as flow facts) written on the source code level to the machine code level. To do so, we couple two tools often used during the development of safety-critical hard real-time systems, the formally verified C compiler CompCert and the static WCET analyzer aiT. CompCert stores the AIS annotations given via __builtin_ais_annot() in a special section of the ELF binary, which can later be extracted automatically by aiT

Disassembly of electric vehicle batteries using the example of the Audi Q5 hybrid system

The rising number of electric vehicles comes along with an increasing demand for Li-Ion batteries. As resources such as lithium are valuable it is economically worthwhile to recycle EV batteries. One of the first steps of every battery recycling process is the disassembly, which can be a quite time and cost consuming process and hence has to be planned properly. Using the battery of the hybrid car Audi Q5 as a case study, a planning approach for the disassembly will be discussed in this paper. Therefore, disassembly sequences will be derived from a priority matrix and a disassembly graph will be drawn up. Finally, recommendations for the design of the disassembly system and work stations will be given.Audi AG and Electrocycling GmbHAutomotive Research Center Niedersachsen (NFF)German Federal Ministry for the Environment, Nature Conservation and Nuclear Safet

Unique coding for authentication and anti-counterfeiting by controlled and random process variation in L-PBF and L-DED

Additive manufacturing technologies enable various possibilities to create and modify the material composition and structure on a local level, but are often prone to undesired defects and inhomogeneities. This contribution makes use of such flaws to generate material-inherent, hidden codes and watermarks in metals for authentication and anti-counterfeiting applications. By controlled and random process variation, unique codes that can be read and authenticated by an eddy current device were produced with the processes of laser powder bed fusion (L-PBF) and laser directed energy deposition (L-DED). Two approaches are presented: First, volumetric, porous structures with a defined shape are manufactured with L-PBF. Second, coatings are fabricated by L-DED with alternating process parameters, leading to local deviations of the magnetic permeability. This non-deterministic coding approach generates a distinctive material structure that triggers high signal amplitudes in the eddy current measurement. Counterfeiting becomes impossible due to the irreproducible melt pool dynamics. Statistical hypothesis testing proves that the system is able to prevent false acceptance or rejection of a code with a certainty of 500 million to one. A low-cost setup for a novel locking system demonstrates that a code can be sensed reliably within one second

Aspatial Peripherality in Europe

"Aspatial Peripherality, Innovation and the Rural Economy" (AsPIRE) was a European research project funded by the EU Fifth Framework Programme concerned with the changing nature of peripheral regions. Recent advances in transport and communication technology have created the potential for fundamental changes in relationships between highly accessible "core" and less accessible "peripheral" regions. Some peripheral regions have taken advantage of these new opportunities, while others perhaps more accessible regions lag behind. The AsPIRE project aimed at explaining these differences in response. 'Aspatial peripherality' is a term devised by the project team to describe a range of processes to compensate for the handicaps associated with remote locations. The report presented here was a contribution of the Institute of Spatial Planning, University of Dortmund to AsPIRE. It developed cartographic patterns of aspatial peripherality and a quantitative analysis of the linkages between different "soft" and "hard" factors of aspatial peripherality and key economic indicators

Development of a novel biodegradable porous iron-based implant for bone replacement

Bone replacement and osteosynthesis require materials which can at least temporarily bear high mechanical loads. Ideally, these materials would eventually degrade and would be replaced by bone deposited from the host organism. To date several metals, notably iron and iron-based alloys have been identified as suitable materials because they combine high strength at medium corrosion rates. However, currently, these materials do not degrade within an appropriate amount of time. Therefore, the aim of the present study is the development of an iron-based degradable sponge-like (i.e. cellular) implant for bone replacement with biomechanically tailored properties. We used a metal powder sintering approach to manufacture a cylindrical cellular implant which in addition contains phosphor as an alloying element. No corrosion inhibiting effects of phosphorus have been found, the degradation rate was not altered. Implant prototypes were tested in an animal model. Bone reaction was investigated at the bone-implant-interface and inside the cellular spaces of the implant. Newly formed bone was growing into the cellular spaces of the implant after 12 months. Signs of implant degradation were detected but after 12 months, no complete degradation could be observed. In conclusion, iron-based open-porous cellular biomaterials seem promising candidates for the development of self-degrading and high load bearing bone replacement materials

4D Printing at the Microscale

3D printing of adaptive and dynamic structures, also known as 4D printing, is one of the key challenges in contemporary materials science. The additional dimension refers to the ability of 3D printed structures to change their properties—for example, shape—over time in a controlled fashion as the result of external stimulation. Within the last years, significant efforts have been undertaken in the development of new responsive materials for printing at the macroscale. However, 4D printing at the microscale is still in its early stages. Thus, this progress report will focus on emerging materials for 4D printing at the microscale as well as their challenges and potential applications. Hydrogels and liquid crystalline and composite materials have been identified as the main classes of materials representing the state of the art of the growing field. For each type of material, the challenges and critical barriers in the material design and their performance in 4D microprinting are discussed. Importantly, further necessary strategies are proposed to overcome the limitations of the current approaches and move toward their application in fields such as biomedicine, microrobotics, or optics

Processing and transaction concepts for cooperation of engineering workstations and a database server

A DBMS kernel architecture is proposed for improved DB support of engineering applications running on a cluster of workstations. Using such an approach, part of the DBMS code - an application-specific layer - is allocated close to the corresponding application on a workstation while the kernel code is executed on a central server. Emperical performance results from DB-based engineering applications are reported to justify the chosen DBMS architecture. The paper focuses on design issues of the application layer including server coupling, processing model and application interface. Moreover, a transaction model for long-term database work in a coupled workstation-server environment is investigated in detail

Coupling engineering workstations to a database server

A DBMS kernel architecture is proposed for improved DB support of engineering applications running on a cluster 01 workstations. Using such an approach, part of the DBMS code - an application-specific layer - is allocated close to the corresponding application on a workstation while the kernel code is executed on a central server. Empirical performance results from DB-based engineering applications are reported to justify the chosen DBMS architecture. The paper focuses on design issues of the application layer including server coupling, processing model and application interface. Moreover, a transaction model for long-term database work in a coupled workstation-server environment is investigated in detail

Technical options for saving plant protection products in fruit-growing

Pflanzenschutzmitteleinsparungen und die Abdriftreduzierung sind wichtige gesellschaftlich und politisch formulierte Ziele. Technische Entwicklungen im Bereich der Applikationstechnik für den Obstbau können dazu beitragen, die Vorgaben zu erfüllen. Der Einsatz von abdriftreduzierten Düsen, Tunnelsprühgeräten, Sensoren zur Laubwanderkennung und Lückenschaltungen, sowie neue Berechnungsmodelle zur Kalkulation des Pflanzenschutzmittelbedarfs sind Ansätze, die in den letzten Jahren verfolgt worden sind und in diesem Beitrag vorgestellt werden.Savings of pesticides and drift reduction are important social and political goals. Technical progress in the field of application techniques may contribute to the achievement of these objectives. The use of low-drift nozzles, tunnel sprayers, sensors for foliage detection and gap switching systems, as well as new computation models are concepts which have been pursued in recent years and which will be described in this paper