Steganographer Identification

Conventional steganalysis detects the presence of steganography within single objects. In the real-world, we may face a complex scenario that one or some of multiple users called actors are guilty of using steganography, which is typically defined as the Steganographer Identification Problem (SIP). One might use the conventional steganalysis algorithms to separate stego objects from cover objects and then identify the guilty actors. However, the guilty actors may be lost due to a number of false alarms. To deal with the SIP, most of the state-of-the-arts use unsupervised learning based approaches. In their solutions, each actor holds multiple digital objects, from which a set of feature vectors can be extracted. The well-defined distances between these feature sets are determined to measure the similarity between the corresponding actors. By applying clustering or outlier detection, the most suspicious actor(s) will be judged as the steganographer(s). Though the SIP needs further study, the existing works have good ability to identify the steganographer(s) when non-adaptive steganographic embedding was applied. In this chapter, we will present foundational concepts and review advanced methodologies in SIP. This chapter is self-contained and intended as a tutorial introducing the SIP in the context of media steganography.Comment: A tutorial with 30 page

Using effective student-centred activities to meet current challenges at Austrian schools

One way of facing the manifold current challenges in the Austrian school system lies in employing project- oriented ways of teaching and learning. One the one hand, these have to be understood as being very complex; on the other hand, the use of the term ‘project’ can be regarded as overused, i.e., inflationary: Many methods are inadequately referred to as projects, thus names are played with. The following paper systematically shows up the opportunities this teaching and learning method boasts, it outlines how the enhancement of competences and learning processes can be initiated, and also discusses the problems and limitations that may arise.Una forma de hacer frente a los cambios del sistema escolar austriaco consiste en emplear actividades de proyectos en la enseñanza y el aprendizaje. Por una parte tiene que ser visto como algo muy complejo y, por otra, la utilización del término projecto puede ser considerada como excesiva y abusivamente usada: muchos metodos se denominan inadecuadamente como proyectos y simplemente untilizan el nombre. El artículo muestra de manera sistemática las oportunidades de este método de enseñanza y aprendizaje, destaca como puede hincarse el potenciamento de las competencias y procesos de aprendizaje, y analiza los problemas y limitaciones que pueden aparecer

Teaching economics outside one's own subject area at lower secondary level in Austria – enriching or embarrassing?

Purpose: This paper will examine the extent to which Economics education within the integrated Austrian subject of Geography and Economics delivered by teachers outside their own subject area differs from teaching delivered by those with a formal qualification in the subject.  Design: Hypothesis testing was carried out using variance analyses, factor analyses and χ² independence tests; qualitative content analysis was used to evaluate responses to the open questions of a questionnaire (Mayring 2000, Kuckartz 2012).  Findings: The results show significant differences between the two teacher groups with regard to the popularity of Economics education, attitudes towards economics generally, and professional self-image.  Limitations and implications: For resource reasons, the study had to be limited to Vienna. A further broader investigation seems necessary.  Practical implications: In order to support teachers working outside their own subject area, two project networks have

An imperfect conjugate gradient algorithm

summary:A new biorthogonalization algorithm is defined which does not depend on the step-size used. The algorithm is suggested so as to minimize the total error after $n$ steps if imperfect steps are used. The majority of conjugate gradient algorithms are sensitive to the exactness of the line searches and this phenomenon may destroy the global efficiency of these algorithms

Climbing the Bio-based Value Pyramid by Novel Transformations

In the last two centuries, the exponential industrial development was propelled by the exploitation of finite and depleting fossil resources, contributing – via the increased level of CO2 in the atmosphere – to climate change. Biomass could serve as an ideal carbon-neutral resource for the production of essential chemicals, until – or in parallel with – the realization of the direct, energy-efficient transformation of atmospheric CO2. This important research area has received a lot of attention in the past decade; however, the transition towards using renewable resources should be critically analyzed to deliver real net CO2 reduction and avoid unfair competition for food/feed. In this thesis, selected examples of neglected waste stream, volumes, potential applications are contrasted with the current demand for certain commodity chemicals. First, the synthesis of jet fuels and polymer building blocks from renewables via catalytic methodologies were demonstrated. Secondly, surfactants were identified as an ideal target for the incorporation of the neglected waste streams, e.g. lignocellulose and used cooking oil. Three high-performance surfactant families were designed, synthesized and characterized, capitalizing on the novel structures that are benign by design and obtained via catalytic methodologies under mild conditions.The present work attempts laying the foundation of profitable upcycling of neglected waste streams and ultimately the development of fully sustainable and economically viable synthesis of high-performance surfactants. They could bring benefits across many local economies: from less developed rural regions to the ultimate testing ground of conscious material management: Space colonies

A Review of Characters Used in the Identification of North Central States\u27 Sitona Germar (Coleoptera, Curculionidae).

Lack of good literature concerning taxonomy of the genus Sitona has prompted this study. Specific characters, such as, color, prothorax shape, frontal groove, punctures, genitalia, setae, eyes, length, elytral shape, and scales are discussed. A key for the five species of the North Centro I Stales is presented, including notes on each species