Mixed Valence Europium Nitridosilicate Eu2SiN3

The mixed valence europium nitridosilicate Eu2SiN3 has been synthesized at 900°C in welded tantalum ampules starting from europium and silicon diimide Si(NH)2 in a lithium flux. The structure of the black material has been determined by single-crystal X-ray diffraction analysis (Cmca (no. 64), a=542.3(11) pm, b=1061.0(2) pm, c=1162.9(2) pm, Z=8, 767 independent reflections, 37 parameters, R1=0.017, wR2=0.032). Eu2SiN3 is a chain-type silicate comprising one-dimensional infinite nonbranched zweier chains of corner-sharing SiN4 tetrahedra running parallel [100] with a maximum stretching factor fs=1.0. The compound is isostructural with Ca2PN3 and Rb2TiO3, and it represents the first example of a nonbranched chain silicate in the class of nitridosilicates. There are two crystallographically distinct europium sites (at two different Wyckoff positions 8f) being occupied with Eu2+ and Eu3+, respectively. 151Eu Mössbauer spectroscopy of Eu2SiN3 differentiates unequivocally these two europium atoms and confirms their equiatomic multiplicity, showing static mixed valence with a constant ratio of the Eu2+ and Eu3+ signals over the whole temperature range. The Eu2+ site shows magnetic hyperfine field splitting at 4.2 K. Magnetic susceptibility measurements exhibit Curie-Weiss behavior above 24 K with an effective magnetic moment of 7.5 μB/f.u. and a small contribution of Eu3+, in accordance with Eu2+ and Eu3+ in equiatomic ratio. Ferromagnetic ordering at unusually high temperature is detected at TC=24 K. DFT calculations of Eu2SiN3 reveal a band gap of ∼0.2 eV, which is in agreement with the black color of the compound. Both DFT calculations and lattice energetic calculations (MAPLE) corroborate the assignment of two crystallographically independent Eu sites to Eu2+ and Eu3+

Adaptation Model for Corporate Car Sharing in the Car Rental Industry

The focus of this thesis was on developing an adaption model for implementing a corporate car sharing service within the existing infrastructure of a car rental company. The investigated case companies were a leading Finnish car rental franchisee and an international car sharing subsidiary, largely owned by the car rental franchisor, which offers corporate car sharing solutions in major European countries. Adapting this new service in Finland will help the car rental franchisee to assert its position as one of the market leaders in the competitive car rental industry. Due to confidentiality reasons, the case companies in this study are referred to as the “car rental franchisee”, its “franchisor” and the “car sharing subsidiary”. Primarily qualitative research methodology was utilised in this study. The conceptual framework of the thesis was based on common business modelling theories, which were used to analyse and compare business operations of the case companies. The resulting gap analysis, information collected from public sources, and interviews with stakeholders formed the basis for an adaptation plan. The evaluation of the gap analysis and interviews with stakeholders revealed that the initial approach of utilising the car sharing subsidiary’s technology platform does not represent the ideal solution for a corporate car sharing service in Finland. Operational procedures, on the other hand, can serve as blueprint to a large extent. The outcome of this study is an adaptation plan, including managerial recommendations for the first phase of the implementation process. The author recommends that a corporate car sharing service from the car rental franchisee in Finland will be executed as independent business operation, which matches the perception of the interviewed stakeholders. The recommended technology platform can be operated as a stand-alone system and does therefore not require any integration into the existing IT infrastructure. Key resources, partners and the car rental network are to be utilised on operational level

Verification of the Schorr-Waite Algorithm - From Trees to Graphs

16 pagesInternational audienceThis article proposes a method for proving the correctness of graph algorithms by manipulating their spanning trees enriched with additional references. We illustrate this concept with a proof of the correctness of a (pseudo-)imperative version of the Schorr-Waite algorithm by re finement of a functional one working on trees. It is composed of two orthogonal steps of re finement -- functional to imperative and tree to graph -- fi nally merged to obtain the result. Our imperative speci fications use monadic constructs and syntax sugar, making them close to common imperative languages. This work has been realized within the Isabelle/HOL proof assistant

Discovery of Microservice-based IT Landscapes at Runtime: Algorithms and Visualizations

The documentation of IT landscapes is a challenging task which is still performed mainly manually. Technology and software development trends like agile practices and microservice-based architectures exacerbate the endeavours to keep documentation up-to-date. Recent research efforts for automating this task have not addressed runtime data for gathering the architecture and remain unclear regarding proper algorithms and visualization support. In this paper, we want to close this research gap by presenting two algorithms that 1) discover the IT landscape based on historical data and 2) create continuously architecture snapshots based on new incoming runtime data. We especially consider scenarios in which runtime artifacts or communications paths were removed from the architecture as those cases are challenging to unveil from runtime data. We evaluate our prototype by analyzing the monitoring data from 79 days of a big automotive company. The algorithms provided promising results. The implemented prototype allows stakeholders to explore the snapshots in order to analyze the emerging behavior of the microservice-based IT landscape

Covariance-modulated optimal transport and gradient flows

We study a variant of the dynamical optimal transport problem in which the energy to be minimised is modulated by the covariance matrix of the distribution. Such transport metrics arise naturally in mean-field limits of certain ensemble Kalman methods for solving inverse problems. We show that the transport problem splits into two coupled minimization problems: one for the evolution of mean and covariance of the interpolating curve and one for its shape. The latter consists in minimising the usual Wasserstein length under the constraint of maintaining fixed mean and covariance along the interpolation. We analyse the geometry induced by this modulated transport distance on the space of probabilities as well as the dynamics of the associated gradient flows. Those show better convergence properties in comparison to the classical Wasserstein metric in terms of exponential convergence rates independent of the Gaussian target. On the level of the gradient flows a similar splitting into the evolution of moments and shapes of the distribution can be observed.Comment: 84 pages, 4 figures. Comments are welcom

Course Allocation via Stable Matching

The allocation of students to courses is a wide-spread and repeated task in higher education, often accomplished by a simple first-come first-served (FCFS) procedure. FCFS is neither stable nor strategy-proof, however. The Nobel Prize in Economic Sciences was awarded to Al Roth and Lloyd Shapley for theirwork on the theory of stable allocations. This theory was influential in many areas, but found surprisingly little application in course allocation as of yet. In this paper, different approaches for course allocation with a focus on appropriate stablematchingmechanisms are surveyed. Two such mechanisms are discussed in more detail, the Gale- Shapley student optimal stable mechanism (SOSM) and the efficiency adjusted deferred acceptance mechanism (EADAM). EADAM can be seen as a fundamental recent contribution which recovers efficiency losses from SOSM at the expense of strategy-proofness. In addition to these two important mechanisms, a survey of recent extensions with respect to the assignment of schedules of courses rather than individual courses is provided. The survey of the theoretical literature is complemented with results of a field experiment, which help understand the benefits of stable matching mechanisms in course allocation applications

Business Capability Maps: Current Practices and Use Cases for Enterprise Architecture Management

This paper provides a state-of-the-art report on the usage of business capability maps in enterprise architecture management. We conducted expert interviews with 25 organizations to reveal the benefits and challenges of capability-based enterprise architecture management and evaluated 14 use cases on the feasibility and benefit of using business capability maps in practice. The results reveal increasing interest and acceptance of the approach in practice and among support organizations

Aktuarische Prognose bei Sexualstraftätern : Ergebnisse einer prospektiven Studie mit 785 Tätern unter besonderer Berücksichtigung von relevanten Tätergruppen und Rückfallkategorie

Seit dem 1.1.2002 werden die in Österreich zu einer Gefängnisstrafe verurteilten Sexualstraftäter der Begutachtungs- und Evaluationsstelle für Gewalt- und Sexualstraftäter in Wien gemeldet. Bei allen Gemeldeten sind forensische Basisdaten zu erheben. Eine Untersuchung der Legalbewährung von n = 795 Personen zeigt durchschnittlich vier Jahre nach Entlassung eine allgemeine Wiederverurteilungsrate von 27,5 %, eine einschlägige von 3,8 %. Aus dem Vergleich mit den Prognosewerten des Static-99 wird der Schluss gezogen, dass die Vorhersage sexuell motivierter Rückfallereignisse, die insgesamt selten sind, bei aus Strafhaft entlassenen Vergewaltigern kaum möglich ist. Günstiger erscheint die Korrelation zwischen dem Anstieg der Wiederverurteilungsrate und den entsprechenden Static-99-Werten jedoch für Gewaltdelikte sowie der Gruppe der außerfamiliären Kindesmissbraucher. Nach hier vertretener Auffassung sind daher aktuarische Prognoseinstrumentarien zur Beurteilung des Einzelfalles unzureichend

Systematic assignment of interaction patterns of self-organization to types of decision-making problems using the example of production planning and control

The design of interactions in self-organizing systems remains a challenging task to this day. Nature offers numerous interaction patterns to tackle various decision problems. This paper presents a classification of decision problems, enabling the mapping of interaction patterns in self-organizing systems onto common decision problems in production planning and control. Furthermore, concrete solution proposals for applying the interaction patterns to decision problems in production planning and control are derived and discussed, and their simulated testing is exemplarily designed using an example