874 research outputs found

    Eine Schnittstelle zur Vorhersage von Nutzeranfragen auf Datensätzen

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    Diese Arbeit stellt eine Schnittstelle vor, die, eingebunden in ein Programm, die Aktionen eines Nutzers im Hintergrund auf den lokalen Rechner verarbeitet und speichert, und versucht, aus den gesammelten Daten eine Vorhersage fßr die nächste Aktion zu ermitteln. Eine Nutzeraktion ist dabei durch die Daten eines Datensatzes definiert, die der Nutzer durch die Aktion abfragen mÜchte. Aus einer Reihe von Paaren (Nutzereingabe, extrahierte Daten), die automatisch ßber eine REST-Schnittstelle oder von Hand ßber eine grafische Nutzeroberfläche in das System eingespeist werden kÜnnen, wird ein Modell gewonnen, das fßr jede Aktion alle unmittelbar nachfolgenden Aktionen als Bigramm speichert und ihre Häufigkeit zählt. Die Schnittstelle stellt eine Reihe von Vorhersagestrategien zur Verfßgung. Eine davon nutzt ein kßnstliches neuronales Netz, das das System in die Lage versetzt, auch dann einen Aktionsvorschlag zu machen, wenn der Nutzer zuvor eine vÜllig unbekannte Aktion ausgefßhrt hat. Die Leistungsfähigkeit des neuronalen Netzes wurde an Beispieldaten getestet und evaluiert. Fßr die Evaluation wurden zufällig Modelle mit Aktionsfolgen generiert, die menschliches Verhalten nachahmen sollten. Bei einem stichprobenartigen Durchlauf, bei dem das Modell auf zweitausend generierte Nutzeranfragen trainiert wurde, konnte das System die Aktionen zu 54.3 Prozent replizieren, bei zweihundert Nutzeranfragen im Mittel zu 72.2 Prozent. Bei authentischem menschlichem Nutzerverhalten gibt es gute Grßnde dafßr, anzunehmen, dass die Vorhersage noch leistungsfähiger ist

    Designing the future: strategy, design and the 4th Revolution: an introduction

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    This is an introduction to the special issue of California Management Review on Design Thinking (DT). This special issue joins the growing body of work exploring the idea of DT and whether DT makes a difference in terms enhancing or augmenting the impact of technology—and, as a result, innovation—in a positive way. We have chosen an interesting, relevant, and useful array of papers that provide different approaches, views, and interpretations of applied design thinking. These articles provide both management and scholarly readers with insights in how DT is used, as well as its impact and usefulness in a variety of contexts

    Taxonomy, Taphonomy, and Bioerosion of Lamniform and Carcharhiniform Shark Teeth from Onslow Bay, North Carolina and an Example Extension from the Gulf Coastal Plain of the U.S.A.

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    This dissertation is divided into four sections that feature assemblages of self-collected fossils recovered while SCUBA diving in Onslow Bay, North Carolina, and the Ouachita River near Malvern, Arkansas. Sections one through three focus on Cenozoic lamniform and carcharhiniform shark teeth, including those of large Otodus megalodon, collected from submerged, actively forming lag deposits adjacent to outcrops of the Miocene Pungo River and Pliocene Yorktown formations in Onslow Bay. Section one documents the submerged collecting localities and the taxonomy and biostratigraphic properties of the fossil shark teeth they contain. Section two documents bathymetric controls on the degree of taphonomic reworking and bioerosion of these shark teeth from shallower, intermediate, and deeper shelf localities in Onslow Bay. Section three identifies and utilizes bioerosion in megatoothed shark teeth in addition to radiocarbon dating of endolithic bivalves and corals to time the process of lag deposit formation. Section four consists of a research extension into the Gulf Coastal Plain of the USA and focuses on an assemblage of Teredolites-bored driftwood recovered from a fossiliferous lag deposit at the contact between the Arkadelphia Formation and Midway Group submerged in the Ouachita River near Malvern, Arkansas. This driftwood derives from a known Cretaceous-Paleogene (K-Pg) boundary section and features trace fossils similar to those occurring in megatoothed shark teeth from Onslow Bay. Although the Malvern lag deposit is geologically older than those actively forming in Onslow Bay, the processes of lag deposit formation are extremely similar. Lag deposits in both study areas contain diverse, time-averaged vertebrate fossil assemblages with a notable abundance of biostratigraphically significant and taphonomically distinct shark teeth, infrequent terrestrial elements, and accumulated in response to numerous storm events and sea level cyclicity. Moreover, the processes of lag deposit formation observed in the actively forming Onslow Bay lags provide a means to interpret and model the formation of similar deposits, including the Malvern K-Pg lag, preserved in the stratigraphic record. Results from this dissertation indicate that the process of vertebrate lag deposit formation: 1) occurs globally, 2) is independent of geologic age, and 3) is the product of numerous storm events, including impact generated tsunamis, and sea level cyclicity within shallow shelf stratigraphic sections

    Turtles From an Arkadelphia Formation—Midway Group Lag Deposit (Maastrichtian—Paleocene), Hot Spring County, Arkansas, USA

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    The Arkadelphia Formation—Midway Group (Maastrichtian—Paleocene) contact near Malvern, Arkansas preserves a K-Pg boundary assemblage of turtle species consisting of skull, shell, and non-shell postcranial skeletal elements. The Malvern turtles are preserved within a coquina lag deposit that comprises the basalmost Midway Group and also contains an abundance of other reptiles, as well as chondrichthyans, osteichthyans, and invertebrates. This coquina lag deposit records a complex taphonomic history of exhumation and reburial of vertebrate skeletal elements along a dynamic ancestral shoreline in southwestern Arkansas during the late Cretaceous-early Paleocene. Based on stratigraphic occurrence, the Malvern turtle assemblage indicates that these marine reptiles were living at or near the time of the K-Pg mass extinction and represent some of the latest Cretaceous turtles yet recovered from the Gulf Coastal Plain of the United States

    Recurrent pericardial effusion after cardiac surgery: the use of colchicine after recalcitrant conventional therapy

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    Pericardial effusion represents a common postoperative complication in cardiac surgery. Nonetheless, it can be resistant to conventional therapy leading to prolonged in-hospital stay and worsening of clinical conditions

    Negaton and Positon Solutions of the KDV Equation

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    We give a systematic classification and a detailed discussion of the structure, motion and scattering of the recently discovered negaton and positon solutions of the Korteweg-de Vries equation. There are two distinct types of negaton solutions which we label [Sn][S^{n}] and [Cn][C^{n}], where (n+1)(n+1) is the order of the Wronskian used in the derivation. For negatons, the number of singularities and zeros is finite and they show very interesting time dependence. The general motion is in the positive xx direction, except for certain negatons which exhibit one oscillation around the origin. In contrast, there is just one type of positon solution, which we label [C~n][\tilde C^n]. For positons, one gets a finite number of singularities for nn odd, but an infinite number for even values of nn. The general motion of positons is in the negative xx direction with periodic oscillations. Negatons and positons retain their identities in a scattering process and their phase shifts are discussed. We obtain a simple explanation of all phase shifts by generalizing the notions of ``mass" and ``center of mass" to singular solutions. Finally, it is shown that negaton and positon solutions of the KdV equation can be used to obtain corresponding new solutions of the modified KdV equation.Comment: 20 pages plus 12 figures(available from authors on request),Latex fil

    New data on the ichthyosaur Platypterygius hercynicus and its implications for the validity of the genus

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    The description of a nearly complete skull from the late Albian of northwestern France reveals previously unknown anatomical features of Platypterygius hercynicus (Kuhn 1946), and of European Cretaceous ichthyosaurs in general. These include a wide frontal forming the anteromedial border of the supratemporal fenestra, a parietal excluded from the parietal foramen, and the likely presence of a squamosal, inferred from a very large and deep facet on the quadratojugal. The absence of a squamosal has been considered as an autapomorphy of the genus Platypterygius for more than ten years and has been applied to all known species by default, but the described specimen casts doubt on this putative autapomorphy. Actually, it is shown that all characters that have been proposed previously as autapomorphic for the genus Platypterygius are either not found in all the species currently referred to this genus, or are also present in other Ophthalmosauridae. Consequently, the genus Platypterygius must be completely revised.Peer reviewe

    Piecing together the Lateglacial advance phases of the Reussgletscher (central Swiss Alps)

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    Exposure dating has substantially improved our knowledge about glacier advances during the Younger Dryas (YD) and the early Holocene. The glacier development after the Last Glacial Maximum (LGM) and the timing of morphologically evidenced, earlier Lateglacial re-advances is, however, still widely unknown. In this study we used 10Be surface exposure and radiocarbon dating to address these phases and corresponding landforms in the catchment of the former Reussgletscher (central Swiss Alps). We obtained clear indication for moraine deposition prior to the YD. The oldest samples predate the Bølling–Allerød interstadial (&gt;14.6&thinsp;ka). Morphostratigraphically even older lateral moraines, probably corresponding to terminal positions in the Lake Lucerne, could not be dated conclusively. Due to the geomorphological constraints of the sampling environment, the establishment of a local pre-YD chronology remains a challenge: moraines with adequate numbers of datable boulders were rarely preserved, and age attributions based on few samples are complicated by outliers.</p
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