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

MATLAB Real-time Data Acquisition for Laboratory Froth Flotation Automation

In this paper analog input/output signals are used to control laboratory froth flotation machine using industrial panel PC. Dataacquisition is provided by two Advantech PCI cards, while flotation control is based on connection of adjustable frequency drivefurther connected to AC motor for agitation control, mass flow controller for air flow control, pH and temperature transmitters withaccording probes for pH and temperature logging respectively. Process control is provided by graphical user interface programmedin MATLAB.This practical engineering design allows researchers to set parameter values prior to flotation test as well as log and savemeasured values for further processing

Optimizing the grain size distribution for talc-magnesite ore flotation

Flotation is the only separation method with an universal utilization. Along with the separation of particulate valuable or hazardous components from primary and seconadry mineral raw materials, it is of usage in biotechnologies and water cleaning. The success of the flotation separation crucially depends on the particle size distribution or composition of the ore charge entering the process. The paper deals with the problem of flotation treatment of talc-magnesite ore. The main components of the ore, i.e. talc and magnesite are appreciably different in their grindability and floatability. For such a type of raw material, grinding of the charge plays a very important role in the process. The (unwanted) influence of ultrafine particles on the course of the flotation process is well known. On the other hand, in order to liberate and subsequently to selectively separate both the components, a maximum particle size has to be respected.An influence of artificial samples of selected particle size fractions on the flotation efficiency has been studied experimentally by the quantitative evaluation of flotation products. The flotation experiments on the samples provided an information not obtainable from traditional flotation tests. An adverse effect of the size fraction 0 0.04 mm was revealed, decreasing the flotation selectivity appreciably. These results are of theoretical and practical importance