Unsupervised Parameter Estimation using Model-based Decoder

In this work, we consider the use of a model-based decoder in combination with an unsupervised learning strategy for direction-of-arrival (DoA) estimation. Relying only on unlabeled training data we show in our analysis that we can outperform existing unsupervised machine learning methods and classical methods. The proposed approach consists of introducing a model-based decoder in an autoencoder architecture which leads to a meaningful representation of the statistical model in the latent space of the autoencoder. Our numerical simulations show that the performance of the presented approach is not affected by correlated signals and performs well for both, uncorrelated and correlated, scenarios. This is a result of the fact, that, in the proposed framework, the signal covariance matrix and the DOAs are estimated simultaneously.Comment: Submitted to IEEE for possible publicatio

Model Order Selection with Variational Autoencoding

Classical methods for model order selection often fail in scenarios with low SNR or few snapshots. Deep learning based methods are promising alternatives for such challenging situations as they compensate lack of information in observations with repeated training on large datasets. This manuscript proposes an approach that uses a variational autoencoder (VAE) for model order selection. The idea is to learn a parameterized conditional covariance matrix at the VAE decoder that approximates the true signal covariance matrix. The method itself is unsupervised and only requires a small representative dataset for calibration purposes after training of the VAE. Numerical simulations show that the proposed method clearly outperforms classical methods and even reaches or beats a supervised approach depending on the considered snapshots.Comment: Submitted to IEEE for possible publicatio

Jobs für Deutschland

Abschluss der ifo Jahresversammlung 2006 war eine hochrangig besetzten Podiumsdiskussion zum Thema "Jobs für Deutschland". Diskussionsteilnehmer waren - neben Minister Huber und Prof. Sinn - Prof. Michael Burda, Ph.D., Humboldt-Universität zu Berlin, Prof. Dr. Ingolf Deubel, Staatsminister der Finanzen des Landes Rheinland-Pfalz, Prof. Dr. Dr. h.c. mult. Wolfgang Franz, Europäisches Zentrum für Wirtschaftsforschung, Mannheim, und Prof. Dr. Georg Milbradt, Ministerpräsident des Freistaates Sachsen. Moderiert wurde die Diskussion von Nikolaus Piper von der Süddeutschen Zeitung.Beschäftigungspolitik, Arbeitsnachfrage, Arbeitslosigkeit, Arbeitsangebot, Globalisierung, Deutschland

Cardiac arrest associated with sildenafil ingestion in a patient with an abnormal origin of the left coronary artery: case report

<p>Abstract</p> <p>Background</p> <p>Left coronary artery arising from the right sinus of Valsalva is an uncommon congenital coro-nary anomaly that seems to be associated with sudden death in young patients.</p> <p>Case presentation</p> <p>We report a case of cardiac arrest in a 59-year-old patient after sexual intercourse and Silde-nafil ingestion. A coronary arteriography and an angiographic computed tomography scan subsequently revealed a LCA origin from the right aortic sinus along with an intramural course of the left main stem. In addition a distal stenosis of the right coronary artery was detected. After successful resuscitation without neurological deficits coronary artery bypass surgery was performed.</p> <p>Conclusion</p> <p>To our knowledge, this is the first report demonstrating sudden cardiac arrest associated with Sildenafil ingestion in a patient with this type of coronary anomaly. The question arises, whether a cardiac screening is necessary before a Sildenafil therapy is initiated.</p

Heavy Metal Extraction under Environmentally Relevant Conditions Using 3-Hydroxy-2-Naphthoate- Based Ionic Liquids: Extraction Capabilities vs. Acute Algal Toxicity

We investigated the applicability of three task-specific ionic liquids (ILs) as heavy metal extracting agents by contrasting extraction capabilities with algal toxicity. The compounds tested were trihexyltetradecylphosphonium-, methyltrioctylphosphonium- and methyltrioctylammonium 3-hydroxy-2-naphthoates. Experiments were performed to assess if these ILs can provide environmentally safe residual concentrations of the target metals after extraction. Both pure water and natural mineral water samples were spiked with 20 mu g L-1 of Cu, Ag, Cd, Hg and Pb, respectively. Quantitative extraction (> 99%) of Hg and Ag was achieved. Cu and Hg were below the respective no-observed-effect-concentrations (NOECs) after extraction and Ag below 0.03 mu g L-1. Acute toxicity assays were conducted using two freshwater green algae Raphidocelis subcapitata and Tetradesmus obliquus. Growth inhibition and maximum photochemical quantum yield of photosystem II after 72 h were assessed. ILs were less toxic than similar compounds, but still must be classified as acute toxicants for algae. An inhibiting effect on both growth and chlorophyll fluorescence was observed. The leaching of the ILs into the samples remains a limitation regarding their environmental-friendly applicability. Nonetheless, the extremely efficient removal of Cu, Ag and Hg under environmentally relevant conditions calls for further research, which should focus on the immobilization of the ILs

Arbeitslosigkeit ohne Ende? Die Arbeitsmarkt- und Beschäftigungspolitik der neuen Bundesregierung in der Kontroverse

Am 24. und 25. März 2006 fand an der Akademie für Politische Bildung Tutzing unter der Leitung von Dr. Wolfgang Quaisser und Karl-Heinz Willenborg die Tagung "Arbeitslosigkeit ohne Ende? Die Arbeitsmarkt- und Beschäftigungspolitik der neuen Bundesregierung in der Kontroverse" statt. Im Zentrum der Tagung standen die im Koalitionsvertrag vorgeschlagenen arbeitsmarktpolitischen Maßnahmen. Als Mitglied der Bundesregierung erläutert Franz Müntefering, Bundesminister für Arbeit und Soziales, die Arbeitsmarkt- und Beschäftigungspolitik der Bundesregierung. Hermann Otto Solms, FDP-Bundestagsfraktion, Heike Maria Kunstmann, Gesamtmetall, und Wilhelm Adamy, DGB, nehmen als Vertreter der Opposition, der Arbeitgeber und der Arbeitnehmer Stellung dazu. Joachim Möller, Universität Regensburg, legt seine Bewertung aus wissenschaftlicher Sicht dar. Im Anschluss daran prüfen Peter Hampe, TU Dresden, und Ulrich Walwei, Michael Feil und Lisa Tillmann, IAB, Nürnberg, ob aus der deutschen Wirtschafts- und Arbeitsmarktpolitik seit der Wiedervereinigung Lehren für Deutschland im Kampf gegen die Arbeitslosigkeit gezogen werden können. Zum Abschluss berichten Michael Knogler, Osteuropa-Institut München, und Wolfgang Quaisser, Politische Akademie Tutzing, Wolfgang Ochel, ifo Institut, und Henry Werner, dänische Botschaft, Berlin, über die Arbeitsmarktpolitik der neuen EU-Mitgliedstaaten, der USA sowie Dänemarks.Arbeitslosigkeit, Arbeitsmarktpolitik, Beschäftigungspolitik, Regierung, Deutschland

SAP HANA distributed in-memory database system: Transaction, session, and metadata management

One of the core principles of the SAP HANA database system is the comprehensive support of distributed query facility. Supporting scale-out scenarios was one of the major design principles of the system from the very beginning. Within this paper, we first give an overview of the overall functionality with respect to data allocation, metadata caching and query routing. We then dive into some level of detail for specific topics and explain features and methods not common in traditional disk-based database systems. In summary, the paper provides a comprehensive overview of distributed query processing in SAP HANA database to achieve scalability to handle large databases and heterogeneous types of workloads