Contributions in Merlin

null

We introduce a general framework for models of cascade and contagion processes on networks, to identify their commonalities and differences. In particular, models of social and financial cascades, as well as the fiber bundle model, the voter model, and models of epidemic spreading are recovered as special cases. To unify their description, we define the net fragility of a node, which is the difference between its fragility and the threshold that determines its failure. Nodes fail if their net fragility grows above zero and their failure increases the fragility of neighbouring nodes, thus possibly triggering a cascade. In this framework, we identify three classes depending on the way the fragility of a node is increased by the failure of a neighbour. At the microscopic level, we illustrate with specific examples how the failure spreading pattern varies with the node triggering the cascade, depending on its position in the network and its degree. At the macroscopic level, systemic risk is measured as the final fraction of failed nodes, X*, and for each of the three classes we derive a recursive equation to compute its value. The phase diagram of X* as a function of the initial conditions, thus allows for a prediction of the systemic risk as well as a comparison of the three different model classes. We could identify which model class leads to a first-order phase transition in systemic risk, i.e. situations where small changes in the initial conditions determine a global failure. Eventually, we generalize our framework to encompass stochastic contagion models. This indicates the potential for further generalizations.

We use a regime-switching approach to model the implementation of SNB monetary policy. The regime-switching technique is crucial for assessing the flexibility inherent in the SNB’s monetary policy strategy. The empirical findings support the idea that repo operations are instrumental in smoothing the implementation of monetary policy in normal times, while changes in the official operational target, accompanied by the accommodating use of repo operations, produce the intended effects in periods of distress. Another significant contribution also comes from some new measures designed to improve liquidity in the Swiss franc money market during the financial crisis of 2007–2008.

Cloud computing has gaining importance in the recent past due to the conjunction of well-known key features, such as virtualization and pay-by-use, which together form an innovative concept. Even if cloud computing does not have a widely accepted definition, it has been used for many companies to deploy its infrastructures and promote their business. However, the lack of standards seems to be a drawback related to interoperability and optimization issues. Convenient actions like changing cloud providers, and/or exchange data/information between clouds may be an arduous work for its customers. Therefore, this paper presents major considerations regarding the lack of cloud standards and pointing why this is considered to be a problem. Furthermore, scenarios are discussed, which are desired to make use of cloud interoperabilityand which are currently initiatives addressing cloud standards issues. This leads to a set of important observations towards a solution solving the interoperability and standardization problem.

null

null

null

null