Constructing Mobile Agents using Transformations

Although mobile agents are widely accepted as a useful and elegant way to develop software for distributed systems, they are not widely-used. One of the main reasons for this is the lack of provable and manageable protection of an agent platform. We present a working prototype of a mobile agent programming and execution environment based on term graph transformation and the strongly typed functional programming language Haskell. The well-understood type system of Haskell can be used to guarantee that a mobile agent cannot do arbitrary I/O on an agent platform. Therefore the mobile agent migrates as Haskell source code and is type-checked on each platform. The services a platform offers to a mobile agent are encapsulated in so-called possibly-provided functions (PPFs). A PPF is a function that returns a value of type Maybe a for arbitrary a. A PPF need not be available on all platforms. If it is not available, it will be temporarily replaced with a function returning the value Nothing of type Maybe a by a preprocessor on the agent platform. In order to be able to replace a PPF, the Haskell code is encapsulated in a list of code fragments. A strongly typed mobile agent which consists of one complex function with a complex parameter which has to be encapsulated in a list of code fragments is a very awkward piece of software. The complex parameter is the data part of the mobile agent and is called its suitcase. Conventional programming using a normal text editor is not feasible. Therefore we use the Higher Object Programming System HOPS, a graphically interactive program development and transformation system based on term graphs, for developing a mobile agent. When using HOPS we have the ability to define an easy-to-use domain-specific language for mobile agents and to derive the necessary shape of the mobile agent code using term graph transformation. Not only the encapsulation into the code fragment data type can be automated, but also the complex suitcase can be generated automatically from small manageable pieces. With this thesis we demonstrate that the combination of a strongly typed functional language and a development process which is aided by term graph transformation together with our concept of PPFs is a very well suited approach towards a fully-fledged mobile agent system.Obwohl mobile Agenten weitestgehend akzeptiert wurden als nützliche und elegante Art Software für verteilte Systeme zu entwicklen, werden sie kaum eingesetzt. Einer der Hauptgründe dafür ist das Fehlen eines beweisbaren und beherrschbaren Schutzmechanismus für eine Agentenplattform. Wir präsentieren mit dieser Arbeit einen funktionstüchtigen Prototyp einer Programmier- und Ausführungsumgebung für mobile Agenten basierend auf Termgraph Transformation und der rein funktionalen Programmiersprache Haskell. Das Typsystem von Haskell kann garantieren, dass ein mobiler Agent keine beliebigen E/A Aktionen auf einer Agentenplattform ausführen kann. Um es zu nutzen migriert der mobile Agent asl Haskell Quellcode und der Typ wird auf jeder Agentenplattform überprüft. Die Dienste die eine Agentenplattform den mobilen Agenten zur Verfügung stellt, sind in sogennannte possibly-provided functions (PPFs) gekapselt. Eine PPF ist eine Funktion die einen Wert vom Typ Maybe a für ein beliebiges a zurückliefert. Eine PPF muß nicht auf jeder Plattform vorhanden sein. Wenn die PPF nicht vorhanden ist, wird sie temporär von einem Präprozessor durch eine Funktion die den Wert Nothing liefert ersetzt. Um eine solche Ersetzung möglich zu machen, wurde der Haskell code in eine Liste sogenannter Code Fragmente eingebettet. Ein streng typisierter mobiler Agent der aus einer komplexen Funktion mit einem komplexen Parameter besteht, die in eine Liste von Code Fragmenten eingebettet werden muß, ist ein schwierig zu handhabendes Stück Software. Der komplexe Parameter ist der Datenteil des mobilen Agenten und wird Suitcase genannt. Herkömmliche Programmierung mit einem gewöhnlichen Texteditor ist nicht praktikabel. Aus diesem Grunde nutzen wir das Higher Object Programming System HOPS, ein graphisches, interaktives Programmentwicklungs- und -transformationssystem basierend auf Termgraphen, für die Entwicklung eines mobilen Agenten. Durch die Verwendung von HOPS ist es möglich eine einfach zu nutzende Domain-Specific Language für mobile Agenten zu definieren und mittels Termgraph Transformation die benötigte Form daraus herzuleiten. Neben der Einbettung des mobile Agenten in die Liste der Code Fragmente kann der komplexe Suitcase aus kleinen, überschaubaren Teilen generiert werden. Mit dieser Arbeit haben wir gezeigt, dass die Kombination einer streng typisierten, funktionalen Programmiersprache und einem Softwareentwicklungsprozess der durch Termgraph Transformation unterstützt wird, zusammen mit unserem Konzept der PPFs, ein sehr gut geeigneter Ansatz in Richtung eines vollwertigen System für mobile Agenten ist

Permutation Tests for Random Effects in Linear Mixed Models

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92041/1/j.1541-0420.2011.01675.x.pd

Web-based instruments for strengthening sustainable regional development in the Alps

Web-based information and communication technologies enable the inclusion of all stakeholders in sustainable regional development and raise hopes that these processes will be accomplished from the bottom up and with broad public participation. This article synthesizes, presents, and critically discusses solutions for the Alps that use web 2.0 technologies, in particular: (a) GALPIS and DIAMONT with databases and an interactive webGIS, (b) mountain.TRIP as an efficient communication and information system to link research with practice, and (c) mountain wikis as tools for collaborative regional planning and development. The results indicate that new information and communication instruments enhance the implementation, promotion, assessment, and steering of sustainable regional development in the Alps

Old stones’ song—second verse: use-wear analysis of rhyolite and fenetized andesite artifacts from the Oldowan lithic industry of Kanjera South, Kenya

This paper investigates Oldowan hominin behavioral ecology through use-wear analysis of artifacts from Kanjera South, Western Kenya. It extends development of our experimental use-wear reference collection and analysis of use-wear on the well preserved and unweathered Oldowan tools from this site to include rhyolite, a non-local material of similar durability to previously studied quartz and quartzite tools, and fenetized andesite, a local material with considerably less durability. Variability in rhyolite and fenetized andesite texture, inclusions, and matrix required enhancement of previous methods so we combine the use of stereoscopic, metallographic, and scanning electron microscopy in this study. This study allows us to begin exploration of the links between specific artifactual raw materials and the materials they were used to process. Data assembled so far suggest that tools fashioned from non-local and local stone were, with one possible exception, used to process similar materials. Additionally, experiments carried out with replicas of tools made of rhyolite and fenetized andesite confirm interpretation of reduction sequences that tools made of less durable local material had a shorter use-life and were used expediently compared to the more durable non-local quartz, quartzite, and rhyolite. These new data improve our understanding, of the functional needs, behavioral solutions, and cognitive capacities of Oldowan hominins. Finally, these data show how use-wear analysis, combined with lithic raw material and lithic technology, can be a powerful means for evaluating two key points for human evolution: long-term memory, and planning

Probing molecular free energy landscapes by periodic loading

Single molecule pulling experiments provide information about interactions in biomolecules that cannot be obtained by any other method. However, the reconstruction of the molecule's free energy profile from the experimental data is still a challenge, in particular for the unstable barrier regions. We propose a new method for obtaining the full profile by introducing a periodic ramp and using Jarzynski's identity for obtaining equilibrium quantities from non-equilibrium data. Our simulated experiments show that this method delivers significant more accurate data than previous methods, under the constraint of equal experimental effort.Comment: 4 pages, 3 figure

Limnological changes and chironomid-inferred summer air temperature from the Late Pleniglacial to the Early Holocene in the East Carpathians

Here we provide the first chironomid record and associated summer air-temperature (T VII ) reconstruction between ca. 16,800-9100 cal yr BP from Lake Saint Anne (SZA), situated in the Eastern Carpathians. SZA was formed by the youngest volcanic eruption of Ciomadul volcano at ca. 29,600 cal yr BP. Our main goals in this study are to test whether warming after Heinrich event 1 (H1; ca. 16,200 cal yr BP) had similar amplitude to the late glacial warming, while Younger Dryas (YD) summers remained relatively warm in this region of Europe. We found the most remarkable chironomid assemblage change with a T VII increase of ~3.5-3.8°C at ca. 16,350 cal yr BP at SZA, followed by another slight T VII increase of ~0.8-1.0°C at ca. 14,450 cal yr BP. Only very minor temperature variations were recorded between 14,450 cal yr BP and 11,700 cal yr BP, with an unexpected T VII decrease in the Early Holocene. Variations in water depth together with increasing analogue problems and paludification from ca. 14,200 cal yr BP onwards may have influenced the reliability of our paleotemperature record obtained from SZA. In addition, Sphagnum -indicated decreasing pH, and hence decreasing nutrient level, likely overrode the effect of summer air-temperature changes during the Early Holocene, and this may explain the bias in the chironomid-inferred summer air-temperature reconstruction in the Early Holocene section

Исследование влияния концентрации соли на результат измерения погонной емкости кабеля

Описан метод измерения погонной емкости электрического кабеля непосредственно в процессе производства. Осуществлен анализ влияния электропроводности воды на результаты измерения емкости кабеля

Ferroelectricity and Crystal Phases in Mixed‐Cation Lead Iodide Perovskite Solar Cells

After the discovery of ferroelectricity in archetypal methylammonium lead iodide (MAPbI$_3$), the discussion arose, if more advanced derivatives thereof are also ferroelectric and to what extent the polar domains mitigate detrimental charge carrier recombination in perovskite solar cells. Herein, the A-site cation methylammonium is gradually substituted with formamidinium and cesium. The domain contrast measured by piezoresponse force microscopy is correlated with the distortion of the crystal structure measured by X-ray diffraction. By Rietveld analysis, a detailed structural model together with texture information is determinded, which reveals an intriguing interplay between lead iodide and the perovskite phases. Finally, the bearing of ferroelectric domains in mixed-cation perovskites on the solar cell performance is discussed

Epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany: a systematic review

Damm O, Witte J, Wetzka S, et al. Epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany: a systematic review. INTERNATIONAL JOURNAL OF PUBLIC HEALTH. 2016;61(7):847-860.Despite the availability of vaccines and the existence of public vaccination recommendations, outbreaks of vaccine-preventable childhood diseases still cause public health debate. The objective of this systematic review was to provide an overview of the current epidemiology and economic burden of measles, mumps, pertussis, and varicella in Germany. We systematically reviewed studies published since 2000. The literature search was conducted using PubMed and EMBASE. Also, we used German notification data to give an up-to-date overview of the epidemiology of the four diseases under consideration. Thirty-six studies were included in our review. Results suggest that there is still considerable morbidity due to childhood diseases in Germany. Studies providing cost estimates are scarce. Comparative analyses of different data sources (notification data vs. claims data) revealed a potential underestimation of incidence estimates when using notification data. Furthermore, several studies showed regional differences in incidence of some of the diseases under consideration. Our findings underline the need for improved vaccination and communication strategies targeting all susceptible age and risk groups on a national and local level