1,428 research outputs found

    Covert Android Rootkit Detection: Evaluating Linux Kernel Level Rootkits on the Android Operating System

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    This research developed kernel level rootkits for Android mobile devices designed to avoid traditional detection methods. The rootkits use system call hooking to insert new handler functions that remove the presence of infection data. The effectiveness of the rootkit is measured with respect to its stealth against detection methods and behavior performance benchmarks. Detection method testing confirms that while detectable with proven tools, system call hooking detection is not built-in or currently available in the Google Play Android App Store. Performance behavior benchmarking showed that system call hooking affects the completion time of the targeted system calls. However, this delay\u27s magnitude may not be noticeable by users. The rootkits implemented targets Android 4.0 on the emulator available from the Android Open Source Project (AOSP) and the Samsung Galaxy Nexus. The rootkits are compiled against both Linux kernel 2.6 and 3.0, respectively. This research shows the Android\u27s Linux kernel is vulnerable to system call hooking and additional measures should be implemented before handling sensitive data with Android

    Bullying Roles in Changing Contexts: The Stability of Victim and Bully Roles from Primary to Secondary School

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    The present study was conducted to predict bullying roles over a six years time period and across contexts differing in the degree of peer hierarchies. Out of two representative data sets from primary (N = 1525) and secondary school (N = 2958), 282 children (156 boys; 126 girls) were followed up longitudinally. Self reports on bullying experiences and peer reports about social status were assessed by a structured individual interview (in primary school) and by questionnaire given classwise (in secondary school). Risk analyses showed, that only a bully role in primary school yields a risk to be sustained in secondary school. However, victims in primary school classes with a more pronounced degree of hierarchical structuring proved stable in their role while the victim role was unstable from primary school classes with low hierarchical structuring. This interaction did not apply to bully role stability. Differential characteristics of the victim and the bully role in primary school and secondary school settings are discussed.Die vorliegende Untersuchung wurde durchgeführt, um Bullyingrollen über einen Zeitraum von sechs Jahren und Kontexte, die sich im Ausmaß der sozialen Strukturierung unterschieden, vorherzusagen. Auf der Grundlage von zwei repräsentativen Datensätzen aus der Grundschule (n= 1525) und der weiterführenden Schule (N= 2958) wurden dazu die Daten von 282 Kinder (156 Jungen, 126 Mädchen) längsschnittlich analysiert. Die Selbstberichte über Bullyingerfahrungen und Mitschülerberichte über den sozialen Status der Kinder wurden in der Grundschule durch ein strukturiertes Interview und in der weiterführenden Schule durch klassenweise Fragebogenerhebung erfasst. Riskikoanalysen zeigen, dass nur die Täterrolle in der Grundschule einen Risikofaktor für eine Täterrolle in der weiterführenden Schule darstellt. Eine Opferrolle war hingegen nur dann stabil, wenn die Opfer in Grundschulklassen mit schon ausgeprägten Dominanzstrukturen viktimisiert wurden, während aus Grundschulklassen mit geringer hierarchischer Strukturierung keine stabile Opferrolle vorhersagbar war. Dieses Interaktionmuster gilt nicht für die Stabilität der Täterrollen. Differentielle Charakteristika der Opferrolle und der Täterrolle in der Grundschule und der weiterführenden Schule werden diskutiert

    THE SPEECH BEHAVIOUR OF INFANTS WITHOUT FAMILIES

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    Does an adequate team climate for learning predict team effectiveness and innovation potential? A psychometric validation of the Team Climate questionnaire for Learning in an organizational context

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    This paper reports the application and psychometric validation of a multi-dimensional measure of team climate for learning in a multinational organization. The research project aimed at extending previous findings at Aston Business School, using the English 33-item version of Brodbeck's Team Climate questionnaire for Learning to assess the factors that facilitate team learning in a business context and analyze its relationship to group performance, support for innovation and different effectiveness criteria chosen by the organization we cooperated with. Data concerning the TCL, the level of group development as a related process, and measures of group performance, innovation and effectiveness were gathered from 119 participants belonging to 18 work groups of the organization's headquarters and three subsidiaries in Germany, Switzerland and Belgium. The undertaken studies were carried out using a cross-sectional and correlated design. The assessment tool proved to have good psychometric properties, providing an adequate reliability, validity and power of prediction regarding team performance (R² = .81), support for innovation (R² = .69) and team effectiveness (e.g. R² = .59 as regards to the keeping of deadlines). Potential benefits derived from the application of the presented measure, limitations of the current research project and future perspectives are discussed

    Controlled lasing from active optomechanical resonators

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    Planar microcavities with distributed Bragg reflectors (DBRs) host, besides confined optical modes, also mechanical resonances due to stop bands in the phonon dispersion relation of the DBRs. These resonances have frequencies in the sub-terahertz (10E10-10E11 Hz) range with quality factors exceeding 1000. The interaction of photons and phonons in such optomechanical systems can be drastically enhanced, opening a new route toward manipulation of light. Here we implemented active semiconducting layers into the microcavity to obtain a vertical-cavity surface-emitting laser (VCSEL). Thereby three resonant excitations -photons, phonons, and electrons- can interact strongly with each other providing control of the VCSEL laser emission: a picosecond strain pulse injected into the VCSEL excites long-living mechanical resonances therein. As a result, modulation of the lasing intensity at frequencies up to 40 GHz is observed. From these findings prospective applications such as THz laser control and stimulated phonon emission may emerge

    The Binary Collision-Induced Second Overtone Band of Gaseous Hydrogen: Modelling and Laboratory Measurements

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    Collision-induced absorption (CIA) is the major source of the infrared opacity of dense planetary atmospheres which are composed of nonpolar molecules. Knowledge of CIA absorption spectra of H2-H2 pairs is important for modelling the atmospheres of planets and cold stars that are mainly composed of hydrogen. The spectra of hydrogen in the region of the second overtone at 0.8 microns have been recorded at temperatures of 298 and 77.5 K for gas densities ranging from 100 to 800 amagats. By extrapolation to zero density of the absorption coefficient measured every 10 cm(exp -1) in the spectral range from 11100 to 13800 cm(exp -1), we have determined the binary absorption coefficient. These extrapolated measurements are compared with calculations based on a model that was obtained by using simple computer codes and lineshape profiles. In view of the very weak absorption of the second overtone band, we find the agreement between results of the model and experiment to be reasonable

    Shedding Light on Team Adaptation: Does Experience Matter?

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    Investigating the team adaptation process in two laboratory experiments (N = 144 teams, n = 504 participants), we found no benefits for teams with team adaptation experience (vs. without) nor for teams with external team adaptation experience (vs. with internal experience). Collective experience under routine and nonroutine conditions seems to provide teams with the resources to adapt. We further found that executing the team adaptation process did not always lead to high team performance; different team performance requirements might explain these findings. We discuss how our experimental findings can extend our understanding of team adaptation toward new boundary conditions

    Being on the same page about social rules and norms: Effects of shared relational models on cooperation in work teams

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    In working teams, each member has an individual understanding of the social rules and norms that underlie social relationships in the team, as well as about what behavior is appropriate and what behavior can be expected from others. What happens if the members of a team are not “on the same page” with respect to these social rules and norms? Drawing on relational models theory, which posits four elemental relational models that people use to coordinate their social interactions, we examined the effects of a common understanding of relational models in teams (i.e., “shared relational models”) on various aspects of cooperative and uncooperative behaviors. We hypothesized that a shared understanding of relational models in a team is positively related to justice perception and negatively related to relationship conflict, which are in turn related to helping behavior and knowledge hiding. We conducted a field study, collecting data from 46 work teams (N = 189 total participants) in various organizations, and found support for all proposed hypotheses. Our findings emphasize the importance of a shared understanding of relational models for (un)cooperative behavior in teams, thereby opening a new door for research on relational models in organizations

    Nuo Hans Gross iki lazerinio skenavimo – nusikaltimo vietos fiksavimo principai dabar ir tada

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    Hans Gross created with the first print of his book “Handbuch für Untersuchungsrichter, Polizeibeamte, Gendarmen, usw.“ a standard volume for the work at crime scenes in 1893. This book was published in several editions over a time period of decades. Throughout the time the technology, which is used for crime scene documentation, has changed, correlated to the then actual available technology. This article gives an overview about the changes in the technologies used at crimes scenes for documentation between 1893 and 2022. It describes the way from sketching and modelling to photography, Infrared-photography, spherical panoramic photography and laser scanning. Many modern technologies are based upon scientific principles which were described decades ago, although people think, that they are new. This article also takes a look upon what principles for the work at crime scenes, postulated by Hans Gross, are still valid today
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