Distributed enterprise search using software agents

In this paper we introduce a distributed information retrieval system using agent-based technology. In this multiagent system, each agent has its own specific task and can be used to handle a specific document repository. The system is designed to automatically comply with access restriction rules that are normally enforced in companies. It is used in the administration offices of the German capital city Berlin where it serves as a testbed for further research on aggregated search in an enterprise environment with roughly 50,000 employees

Comparing Gravitational Waveform Extrapolation to Cauchy-Characteristic Extraction in Binary Black Hole Simulations

We extract gravitational waveforms from numerical simulations of black hole binaries computed using the Spectral Einstein Code. We compare two extraction methods: direct construction of the Newman-Penrose (NP) scalar $\Psi_4$ at a finite distance from the source and Cauchy-characteristic extraction (CCE). The direct NP approach is simpler than CCE, but NP waveforms can be contaminated by near-zone effects---unless the waves are extracted at several distances from the source and extrapolated to infinity. Even then, the resulting waveforms can in principle be contaminated by gauge effects. In contrast, CCE directly provides, by construction, gauge-invariant waveforms at future null infinity. We verify the gauge invariance of CCE by running the same physical simulation using two different gauge conditions. We find that these two gauge conditions produce the same CCE waveforms but show differences in extrapolated-$\Psi_4$ waveforms. We examine data from several different binary configurations and measure the dominant sources of error in the extrapolated-$\Psi_4$ and CCE waveforms. In some cases, we find that NP waveforms extrapolated to infinity agree with the corresponding CCE waveforms to within the estimated error bars. However, we find that in other cases extrapolated and CCE waveforms disagree, most notably for $m=0$ "memory" modes.Comment: 26 pages, 20 figure

Linear Thermal Expansion Coefficient of the NaCl Phase of CsCl

Cesium chloride undergoes a phase change from the low-temperature CsCI structure to the high-temperature NaCI structure at about 469°C.l There is a volume increase of about 16% when the NaCI structure appears.1 The nature of the transition is of interest, as are the physical properties of the high-temperature phase. If sufficient high-temperature phase data are available for CsCI, calculations of the heat of transition can be made more accurately

Probing atom-surface interactions by diffraction of Bose-Einstein condensates

In this article we analyze the Casimir-Polder interaction of atoms with a solid grating and an additional repulsive interaction between the atoms and the grating in the presence of an external laser source. The combined potential landscape above the solid body is probed locally by diffraction of Bose-Einstein condensates. Measured diffraction efficiencies reveal information about the shape of the Casimir-Polder interaction and allow us to discern between models based on a pairwise-summation (Hamaker) approach and Lifshitz theory.Comment: 5 pages, 4 figure

Nationale Industriepolitik - brauchen wir nationale Champions?

Sollte der Staat mittels einer aktiven Industriepolitik, die die Belange der Wettbewerbspolitik hintan stellt, Unternehmen "züchten", die im Wettbewerb auf dem Weltmarkt bestehen können? Für Prof. Dr. Juergen Donges, Universität zu Köln, stoßen staatliche Initiativen zum Champions-Building oder Champions-Defending sehr schnell an Grenzen der Wirksamkeit. Der bessere Weg sei die Schaffung von Rahmenbedingungen, bei denen die Unternehmen einen starken Anreiz haben, im Inland in Forschung und Entwicklung zu investieren und eine rasche Umsetzung von Forschungsergebnissen in neue, marktfähige Produkte zu erreichen. Nach Ansicht von Dr. Dieter Heuskel, Boston Consulting Group, "steht (es) außer Frage, dass die Entwicklung international wettbewerbsfähiger Unternehmensstrategien in erster Linie Aufgabe des Managements ist. Dazu zählt auch die Entscheidung über Investitionen und Standorte. Es bleibt jedoch Aufgabe der Politik - sowohl der nationalen wie vor allem der europäischen Wirtschaftspolitik -, die Wettbewerbsbedingungen so zu gestalten, dass europäische Unternehmen im internationalen Wettbewerb wie auch an ihrem Ausgangsstandort "bewegungsfähig" sind und strategisch agieren können." Für Dr. Kurt Christian Scheel, Bundesverband der Deutschen Industrie, Berlin, ist die Frage nicht, ob wir nationale Champions brauchen, sondern: "Natürlich sind Champions wünschenswert. Aber: Diese sollen sich aus eigener Kraft nach den Gesetzen des Marktes entwickeln. Nur der Markt kann entscheiden, welches Unternehmen wächst und welches scheitert. Die Aufgabe des Staats ist es, durch geeignete Rahmenbedingungen dafür zu sorgen, dass Deutschland für Investitionen attraktiv bleibt, die Grundlage dieses Wachstums sind."Industriepolitik, Wettbewerb, Forschung, Internationaler Wettbewerb, Wachstumstheorie

Towards substrate-reagent interaction of Lochmann-Schlosser bases in THF: bridging THF hides potential reaction site of a chiral superbase

The metalation of N,N-dimethylaminomethylferrocene in THF by the superbasic mixture of nBuLi/KOtBu proceeds readily at low temperatures to afford a bimetallic Li2K2 aggregate containing ferrocenyl anions and tert-butoxide. Starting from an enantiomerically enriched ortho-lithiated aminomethylferrocene, an enantiomerically pure superbase can be prepared. The molecular compound exhibits superbasic behavior deprotonating N,N-dimethylbenzylamine in the α-position and is also capable of deprotonating toluene. Quantum chemical calculations provide insight into the role of the bridging THF molecule to the possible substrate–reagent interaction. In addition, a benzylpotassium alkoxide adduct gives a closer look into the corresponding reaction site of the Lochmann–Schlosser base that is reported herein