A cognitive-behavioral model of problematic online gaming in adolescents aged 12–22 years

The aim of this study was to apply the cognitive behavioral model of problematic Internet use to the context of online game use to obtain a better understanding of problematic use of online games and its negative consequences. In total, 597 online game playing adolescents aged 12–22 years participated in this study. Results showed that the cognitive behavioral model of problematic Internet use can also be used in the context of online game use. More specifically, preference for online social interaction, mood regulation and deficient self-regulation appeared to play an important role in predicting negative outcomes from problematic online game use. Together, these cognitions and behaviors explained 79% of the variance of negative outcomes scores. These findings can be used to develop strategies that aim at reducing problematic online game behavior and its negative consequences.     

Contextual web searches in Facebook using learning materials and discussion messages

The web is nowadays one of the main information sources, and information search is an important area in which many advances have been registered. One approach to improve web search results is to consider contextual information. Usually, information about context has been provided through user logs on previous searches or the monitoring of clicks on first results, but different approaches can be used in specific environments. In a web based learning environment, existing documents and exchanged messages could provide contextual information. So, the main goal of this work is to provide a contextual web search engine based on shared documents and messages posted in a social network used for collaborative learning. Contextual search is provided through query expansion using learning documents (material provided by the teacher) and discussion messages (posts, links and comments that result from the participants’ interactions). A prototype was implemented and used in a learning scenario to acquire the context in a learning community. The proposed approach makes the context acquisition faster and more dynamic as it considers an automatic approach over text processing of documents and discussions. In addition, the results of the query engine with and without the contextual information were compared and the proposed approach using contextual information showed improvements in the precision of the results.     

Logical sensor/actuator : knowledge-based robotic plan execution

Complex tasks are usually described as high-level goals, leaving out the details on how to achieve them. However, to control a robot, the task must be described in terms of primitive commands for the robot. Having the robot move itself to and through an unknown, and possibly narrow, doorway is an example of such a task. It is shown how the transformation from high-level goals to primitive commands can be performed at execution time and an architecture is proposed based on reconfigurable objects that contain domain knowledge and knowledge about the sensors and actuators available. The approach is illustrated using actual data from a real robot.     

A novel automatic algorithm for the segmentation of the lumen of the carotid artery in ultrasound B-mode images

A novel algorithm is proposed for the segmentation of the lumen and bifurcation boundaries of the carotid artery in B-mode ultrasound images. It uses the image contrast characteristics of the lumen and bifurcation of the carotid artery in relation to other tissues and structures for their identification. The relevant ultrasound data regarding the artery presented in the input image is identified using morphologic operators and processed by an anisotropic diffusion filter for speckle noise removal. The information obtained is then used to define two initial contours, one corresponding to the lumen and the other one regarding the bifurcation boundaries, for the application of the Chan-Vese level set segmentation model. A set of longitudinal ultrasound B-mode grayscale images of the common carotid artery was acquired using a GE Healthcare Vivid-e ultrasound system. The results reveal that the new algorithm is effective and robust, and that its main advantage relies on the automatic identification of the carotid lumen, which overcomes the known limitations of the traditional algorithms.     

Student modeling approaches: A literature review for the last decade

This paper constitutes a literature review on student modeling for the last decade. The review aims at answering three basic questions on student modeling: what to model, how and why. The prevailing student modeling approaches that have been used in the past 10 years are described, the aspects of students’ characteristics that were taken into consideration are presented and how a student model can be used in order to provide adaptivity and personalisation in computer-based educational software is highlighted. This paper aims to provide important information to researchers, educators and software developers of computer-based educational software ranging from e-learning and mobile learning systems to educational games including stand alone educational applications and intelligent tutoring systems. In addition, this paper can be used as a guide for making decisions about the techniques that should be adopted when designing a student model for an adaptive tutoring system. One significant conclusion is that the most preferred technique for representing the student’s mastery of knowledge is the overlay approach. Also, stereotyping seems to be ideal for modeling students’ learning styles and preferences. Furthermore, affective student modeling has had a rapid growth over the past years, while it has been noticed an increase in the adoption of fuzzy techniques and Bayesian networks in order to deal the uncertainty of student modeling.     

The yin-yang driving urinary tract infection and how proteomics can enhance research,diagnostics, and treatment

Bacterial urinary tract infections (UTIs) afflict millions of people worldwide both in the community and the hospital setting. The onset, duration, and severity of infection depend on the characteristics of the invading pathogen (yin), as well as the immune response elicited by the infected individual (yang). Uropathogenic Escherichia coli (UPEC) account for the majority of UTIs, and extensive investigations by many scientific groups have elucidated an elaborate pathogenic UPEC life cycle, involving the occupation of extracellular and intracellular niches and the expression of an arsenal of virulence factors that facilitate niche occupation. This review will summarize the current knowledge on UPEC pathogenesis; the host immune responses elicited to combat infection; and it will describe proteomics approaches used to understand UPEC pathogenesis, as well as drive diagnostics and treatment options. Finally, new strategies are highlighted that could be applied toward furthering our knowledge regarding host-bacterial interactions during UTI.     

Probleme bei Planung und Betrieb von Absetzbecken für Straßenabwässer

Sedimentation basins are incorporated into runoff infiltration systems and serve as a retention system, in which the sedimentation of particles occurs as a result of gravitational force. The effectiveness of sedimentation basins in terms of removing particles is highly dependent on design parameters such as their dimensions and drainage times. To evaluate the flow distribution within sedimentation basins, a conceptual model was developed using a tracer and compared to the actual condition at the treatment system. Here, a significant difference in the height of the connecting tube between settling basin and filter basin was found. This leads to a drying out of the basin, which significantly affects the flow rates and hence the sedimentation there. Based on a model experiment with colour tracer, the flow paths were visually represented in the basin, and both the concrete variant and the effects of internal structures were considered. It was found that the incorporation of a baffle led to an improved utilization of the basin, and to water being retained for longer times. Due to the lower flow rate and these longer times, fine and medium-sized sediments could be easily settled. In a field study, the performance of a sedimentation basin for the removal of particles was evaluated based on the influent and effluent concentrations of total suspended solids (TSS). The street runoff treatment plant was monitored for one year and results showed that there was no particle accumulation in the sedimentation basin (there was no permanent retention of the particle loads). The mean TSS concentrations were 89 mg/L at the inlet of the sedimentation basin and 94 mg/L at the end of the settling tank, respectively. The structural design and operation of the system showed higher flow and turbulent flow conditions in the sedimentation basin, in which settlement of fine and medium sized particles was very low; as a result, the soil filter basin was loaded with runoff particles. Thus the particulate matter had to be removed either on the surface of the filter basin or within the porous space of the filter. The build-up of such particles can result in a significant increase of head loss due to clogging; therefore, filters must be maintained by removing the accumulated particles on a regular basis.     

A complexity reduction approach to detectability of switching systems

In this article, we address detectability for the class of linear switching systems. We focus on some hybrid state-space decompositions of the original switching system based on hybrid invariant subspaces, which yield a complexity reduction in checking detectability. We show that the reduced system extracted from the original system is the minimal bisimilar switching system associated with it. An example is also included which shows the applicability and benefits of the proposed approach.