51 research outputs found

    The Role of Political Institutions for the Effectiveness of Central Bank Independence

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    This paper empirically studies the impact of the quality of political institutions on the link between central bank independence and inflation. Making use of data on the evolution of central bank independence over time and controlling for possible nonlinearities, we employ interaction models to identify the conditions under which more central bank independence will enhance a country’s inflation performance. Examining a cross-section of up to 69 countries, we are able to show that granting a central bank more autonomy does not necessarily lead to better inflation performance. To lower inflation by increasing independence, two conditions must be fulfilled: (1) The change in independence must be sufficiently large, and (2) the quality of the political institutions must be sufficiently high.central bank independence, inflation, institutional quality, monetary policy

    Discrete event simulation for the purpose of real-time performance evaluation of distributed hardware-in-the-loop simulators for autonomous driving vehicle validation

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    Hardware-in-the-loop test benches are distributed computer systems including software, hardware and networking devices, which require strict real-time guarantees. To guarantee strict real-time of the simulator the performance needs to be evaluated. To evaluate the timing performance a discrete event simulation model is built up. The input modeling is based on measurements from the real system in a prototype phase. The results of the simulation model are validated with measurements from a prototype of the real system. The workload is increased until the streaming source becomes unstable, by either exceeding a certain limit of bytes or exceeding the number of parallel software processes running on the cores of the central processing unit. To evaluate the performance beyond these limits, the discrete event simulation model needs to be enriched by a scheduler and a hardware model. To provide real-time guarantees an analytical model needs to be built up

    Ensuring Reliable and Predictable Behavior of IEEE 802.1CB Frame Replication and Elimination

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    Ultra-reliable and low-latency communication has received significant research attention. A key part of this evolution are the Time-Sensitive Networking (TSN) standards, which extend Ethernet with real-time mechanisms. To guarantee high reliability, the standard IEEE 802.1CB-2017 Frame Replication and Elimination for Reliability enables redundant communication over disjoint paths. While this mechanism is essential for time-critical applications, the standard contains some fundamental limitations that can compromise safety. Although some of these limitations have been addressed, none of the previous works provide solutions to these problems. This paper presents solutions to four main limitations of the IEEE 802.1CB-2017 standard. These are 1) choosing match versus vector recovery algorithm, 2) defining the length of the sequence history, 3) setting a timer to reset the sequence history, and 4) dimensioning the burst size in case of link failures. We show how these challenges can be solved by using best- and worst-case path delays of the network. We have performed simulations to illustrate the impact of the limitations and prove the correctness of our solutions. Thereby, we demonstrate how our solutions can improve reliability in TSN networks and propose these methods as guidance for users of the IEEE 802.1CB standard

    MMBnet 2017 - Proceedings of the 9th GI/ITG Workshop ‚ÄěLeistungs-, Verl√§sslichkeits- und Zuverl√§ssigkeitsbewertung von Kommunikationsnetzen und Verteilten Systemen‚Äú

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    Nowadays, mathematical methods of systems and network monitoring, modeling, simulation, and performance, dependability and reliability analysis constitute the foundation of quantitative evaluation methods with regard to software-defined next-generation networks and advanced cloud computing systems. Considering the application of the underlying methodologies in engineering practice, these sophisticated techniques provide the basis in many different areas. The GI/ITG Technical Committee ‚ÄúMeasurement, Modelling and Evaluation of Computing Systems‚Äú (MMB) and its members have investigated corresponding research topics and initiated a series of MMB conferences and workshops over the last decades. Its 9th GI/ITG Workshop MMBnet 2017 ‚ÄěLeistungs-, Verl√§sslichkeits- und Zuverl√§ssigkeitsbewertung von Kommunikationsnetzen und Verteilten Systemen‚Äú was held at Hamburg University of Technology (TUHH), Germany, on September 14, 2017. The proceedings of MMBnet 2017 summarize the contributions of one invited talk and four contributed papers of young researchers. They deal with current research issues in next-generation networks, IP-based real-time communication systems, and new application architectures and intend to stimulate the reader‚Äės future research in these vital areas of modern information society

    Monetary Policy Delegation and Transparency of Policy Targets: A Positive Analysis

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    We show that, in a two-stage model of monetary policy with stochastic policy targets and asymmetric information, the transparency regime chosen by the central bank does never coincide with the regime preferred by society. Independent of society’s endogenous choice of delegation, the central bank reveals its inflation target and conceals its output target. In contrast, society would prefer either transparency or opacity of both targets. As a conclusion, the choice of the transparency regime should be part of the optimal delegation solution.central banking; monetary policy; communication; delegation; positive analysis

    A Time-varying Indicator of Effective Monetary Policy Conservatism

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    Based on an extended version of a time-inconsistency model of monetary policy we show that the degree of effective monetary policy conservatism can be uncovered by studying to what extent central banks react to real disturbances. By estimating central bank reaction functions in moving and overlapping intervals for the period of 1985 to 2007 using an ordered logit approach in a panel setting we derive a time-varying indicator of effective monetary policy conservatism for Canada, Sweden, the UK and the US. Employing this indicator we show that increasing effective conservatism tends to lower inflation without increasing the output gap. However, while a higher degree of effective conservatism does not result in lower inflation uncertainty the variance of the output gap tends to decrease.central banking; monetary policy; conservatism; central bank independence; inflation

    Measuring Effective Monetary Policy Conservatism

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    According to the game-theoretic model of monetary policy, inflation is the consequence of time-inconsistent behavior of the monetary authority. The inflation bias can be eased by handing over the responsibility for monetary policy to an independent central bank and appointing a weight-conservative central banker. Countries around the world chose different combinations of central bank independence and conservatism. Most of the existing empirical studies concentrate on measuring legal or factual central bank independence thereby neglecting the degree of conservatism of the monetary authorities. In this paper we show how a joint empirical measure of central bank independence and conservatism can be derived from factual central bank behavior. Based on a panel logit approach we estimate measures of effective monetary policy conservatism for a sample of 11 OECD countries.Central Banking; Conservatism; Central Bank Independence; Inflation

    Specification and Implementation of CAN Arbitration in UPPAAL

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    In dieser Arbeit stellen wir eine durch Zeitautomaten modellierte Spezifikation des Mediumzugriffs im CAN-Protokoll vor sowie ihre Implementierung in UPPAAL. Zeitliche Anforderungen wurden dabei durch entsprechende Uhren-Nebenbedingungen erfasst. Dieses Zeitautomaten-Modell wurde anschlie√üend automatisch verifiziert (Model Checking), wobei mehrere Anforderungen identifiziert wurden, die das CAN Protokoll erf√ľllen mu√ü (wie Deadlock-Freiheit des Modells, √úbertragungsrecht f√ľr die h√∂chstpriore Nachricht, exklusives √úbertragungsrecht f√ľr beliebigen CAN-Adapter nach der gewonnenen Arbitrage etc.). All diese Eigenschaften wurden in einer Variante der temporalen Logik CTL spezifiziert; die automatische Verifikation selbst wurde dabei mit UPPAAL durchgef√ľhrt, einem Model Checker f√ľr zeitautomaten-basierte Modelle

    Next-Generation Satellite Communication Networks

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    This paper gives an overview of our recent activities in the field of satellite communication networks, including an introduction to geostationary satellite systems and Low Earth Orbit megaconstellations. To mitigate the high latencies of geostationary satellite networks, TCP-splitting Performance Enhancing Proxies are deployed. However, these cannot be applied in the case of encrypted transport headers as it is the case for VPNs or QUIC. We summarize performance evaluation results from multiple measurement campaigns. In a recently concluded project, multipath communication was used to combine the advantages of very heterogeneous communication paths: low data rate, low latency (e.g., DSL light) and high data rate, high latency (e.g., geostationary satellite)
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