Steganography is the science of hiding a message signal in a host signal, without any perceptual distortion of the host signal. Using steganography, information can be hidden in the carrier items such as images, videos, sounds files, text files, while performing data transmission. In image steganography field, it is a major concern of the researchers how to improve the capacity of hidden data i...

Even though SQL has become widely accepted as a language for implementing relational database schemas and querying data, there are cases where its users experience the need for new language abstractions which would allow them to express data modeling and querying solutions in a clearer and simpler manner. This paper describes the idea of language extensions to SQL:1999 that come in form of inde...

Knowledge sharing behavior in virtual communities has long been an important area of research. Prior related research has primarily focused on relational virtual community (RVC) where knowledge sharing is regarded as a social exchange behavior, heavily depending on the social concerns such as reciprocity, identification and norms. The objective of our study is to investigate knowledge contribut...

Many works have focused, for over twenty five years, on the integration of the time dimension in databases (DB). However, the standard SQL3 does not yet allow easy definition, manipulation and querying of temporal DBs. In this paper, we study how we can simplify querying and manipulating temporal facts in SQL3, using a model that integrates time in a native manner. To do this, we propose new ke...

A network of peer database management systems differs from conventional multidatabase systems by assuming absence of any central control, no global schema, transient connection of participating peer DBMSs, and evolving coordination among databases. We describe distributed triggers to support data coordination in this setting. The execution of our triggers requires coordination among the involve...

This paper gives a new flavor of what Peter Jagers and his co-authors call ‘the path to extinction’. In a neutral population with constant size N , we assume that each individual at time 0 carries a distinct type, or allele. We consider the joint dynamics of these N alleles, for example the dynamics of their respective frequencies and more plainly the nonincreasing process counting the number o...

Bei der Anwendungsentwicklung werden komponentenbasierte Methoden bereits erfolgreich eingesetzt. Beim objekt-relationalen Schemaentwurf ist dies allerdings noch nicht der Fall. Dies liegt u.a. daran, dass Konzepte, die einen solchen Entwurf unterstützen, noch nicht im Standard SQL:1999 enthalten sind. In diesem Aufsatz stellen wir Ansätze zur Klassifikation verschiedener Module in objekt-relat...

Sadrzadeh et al (2013) present a compositional distributional analysis of relative clauses in English in terms of the Frobenius algebraic structure of finite dimensional vector spaces. The analysis relies on distinct type assignments and lexical recipes for subject vs object relativisation. The situation for Dutch is different: because of the verb final nature of Dutch, relative clauses are amb...

The paper presents an evolutionary model, based on the assumption that agents may revise their current strategies if they previously failed to attain the maximum level of potential payoffs. We offer three versions of this reflexive mechanism, each one of which describes a distinct type: spontaneous agents, rigid players, and ‘satisficers’. We use simulations to examine the performance of these ...