Graph-Controlled Insertion-Deletion Systems

In this article, we consider the operations of insertion and deletion working in a graph-controlled manner. We show that like in the case of context-free productions, the computational power is strictly increased when using a control graph: computational completeness can be obtained by systems with insertion or deletion rules involving at most two symbols in a contextual or in a context-free manner and with the control graph having only four nodes.Comment: In Proceedings DCFS 2010, arXiv:1008.127

Drip and Mate Operations Acting in Test Tube Systems and Tissue-like P systems

The operations drip and mate considered in (mem)brane computing resemble the operations cut and recombination well known from DNA computing. We here consider sets of vesicles with multisets of objects on their outside membrane interacting by drip and mate in two different setups: in test tube systems, the vesicles may pass from one tube to another one provided they fulfill specific constraints; in tissue-like P systems, the vesicles are immediately passed to specified cells after having undergone a drip or mate operation. In both variants, computational completeness can be obtained, yet with different constraints for the drip and mate operations

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Visual information retrieval and its application to user intentions

The increasing number of videos and images in various multimedia repositories demands for clever content description and indexing techniques to retrieve the visual data in subsequent searches. The main search paradigm in large multimedia databases, whether they are distributed or local, is text-based and relies on additional meta data. Unfortunately meta data is often sparsely distributed over the image and video collection, which entails the need for additional and complementary search paradigms. Visual information retrieval leans onto content-based low level information in terms of color, texture and other features. This work deals with various content-based techniques, applied for video and image retrieval, aiming at new methods to improve ongoing research in the respective fields. Low level approaches for video summarization and retrieval in combination with text as a complementary information source are presented. Well known visual descriptors comprising color and texture information are used in combination with a new motion based approach. Furthermore the Bag of Visual Words (BoVW) approach for visual information retrieval, which is a technique to quantize visual information in the feature space, is extended. The applied fuzzy rules for BoVW are thoroughly discussed in this thesis. Beyond that visual information retrieval is regarded in context of user intentions. User intentions or the goal a user tries to achieve rely on user needs, which are expressed by the users' search behavior. A new approach for retrieval adaptation during content-based image search is presented, which tries to respond appropriately to different goals.Keine Zusammenfassung vorhandenMarian KoglerAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersKlagenfurt, Alpen-Adria-Univ., Diss., 2012KB2012 27OeBB(VLID)241067

P Automata with Controlled Use of Minimal Communication Rules

International audienceno abstrac

Ignesti (Giuseppe) Francia e Santa Sede tra Pio IX e Leone XIII

Durand Jean-Dominique. Ignesti (Giuseppe) Francia e Santa Sede tra Pio IX e Leone XIII. In: Archives de sciences sociales des religions, n°70, 1990. pp. 275-276