The Inhibitive Effect of Traces of SO2 on the Oxidation of Iron

The oxidation of Fe was investigated at 500–700°C in the presence of O₂ with 0–1000 ppm SO₂. The exposures were carried out in a thermobalance and lasted for 24 h. The oxidized samples were investigated by grazing-angle XRD, SEM/EDX, GDOES and XPS. The rate of oxidation of pure iron is slowed down by traces of O₂ in O₂ below 600°C while SO₂ has no effect on oxidation rate at higher temperatures. Exposure to SO₂<600°C resulted in the formation of small amounts of sulfate at the gas/oxide interface. In addition, sulfur, probably sulfide, accumulated at the metal/oxide interface. The influence of SO₂ on oxidation rate is attributed to surface sulfate. The sulfur distribution in the scale is rationalized in terms of the thermodynamic stability of compounds in the Fe–O–S system. Exposure to SO₂ caused the formation of hematite whiskers.     

Consequences of customer engagement behavior: when negative Facebook posts have positive effects

Sharing product information has become an integral part of today’s online social networking world. This research study addresses the effects of customer engagement behavior in online social networks on other consumers in order to understand how online social connections impact decision making. We investigate how different variations of a brand-related Facebook post trigger different response reactions. In particular, we analyze under which conditions negative posts can have positive consequences. The results of two online experiments set in a restaurant context suggest a difference when the user knows the restaurant brand. For users who are familiar with the restaurant brand, a positive effect of negative information posted by distant acquaintances is found with regard to the visiting intention of the user. The results of both experiments demonstrate that information posted by a close friend is perceived to be more diagnostic. For users not familiar with the restaurant brand, negative posts from strong ties induce the highest diagnosticity levels.     

A new method for evaluating the subjective image quality of photographs: dynamic reference

The Dynamic Reference (DR) method has been developed for subjective image quality experiments in which original or undistorted images are unavailable. The DR method creates reference image series from test images. Reference images are presented to observers as a slide show prior to evaluating their quality. As the observers view the set of reference images, they determine the overall variation in quality within the set of test images. This study compared the performance of the DR method to that of the standardized absolute category rating (ACR) and paired comparison (PC) methods. We measured the performance of each method in terms of time effort and discriminability. The results showed that the DR method is faster than the PC method and more accurate than the ACR method. The DR method is especially suitable for experiments that require highly accurate results in a short time.     

Comparing and experimenting machine learning techniques for code smell detection

Several code smell detection tools have been developed providing different results, because smells can be subjectively interpreted, and hence detected, in different ways. In this paper, we perform the largest experiment of applying machine learning algorithms to code smells to the best of our knowledge. We experiment 16 different machine-learning algorithms on four code smells (Data Class, Large Class, Feature Envy, Long Method) and 74 software systems, with 1986 manually validated code smell samples. We found that all algorithms achieved high performances in the cross-validation data set, yet the highest performances were obtained by J48 and Random Forest, while the worst performance were achieved by support vector machines. However, the lower prevalence of code smells, i.e., imbalanced data, in the entire data set caused varying performances that need to be addressed in the future studies. We conclude that the application of machine learning to the detection of these code smells can provide high accuracy (>96 %), and only a hundred training examples are needed to reach at least 95 % accuracy.     

Two CEGAR-based approaches for the safety verification of PLC-controlled plants

In this paper we address the safety analysis of chemical plants controlled by programmable logic controllers (PLCs). We consider a specification of the control program of the PLCs, extended with the specification of the dynamic plant behavior. The resulting hybrid models can be transformed to hybrid automata, for which advanced techniques for reachability analysis exist. However, the hybrid automata models are often too large to be analyzed. We propose two counterexample-guided abstraction refinement (CEGAR) approaches to keep the size of the hybrid models moderate.     

Socially shared regulation of learning in CSCL: understanding and prompting individual- and group-level shared regulatory activities

The field of computer supported collaborative learning (CSCL) is progressing instrumentally and theoretically. Nevertheless, few studies examine the effectiveness and efficiency of CSCL with respect to cognitive, motivational, emotional, and social issues, despite the fact that the role of regulatory processes is critical for the quality of students’ engagement in collaborative learning settings. We review the four earlier lines in developing support in CSCL and show how there has been a lack of work to support individuals in groups to engage in, sustain, and productively regulate their own and the group’s collaborative processes. Our aim is to discuss how our conceptual work in socially shared regulation of learning (SSRL) contributes to effective and efficient CSCL, what tools are presently available, and what the implications of research on these tools are for future tool development.     

ExoPranayama: a biofeedback-driven actuated environment for supporting yoga breathing practices

Both breathing and internal self-awareness are an integral part of any yoga practice. We describe and discuss the development of ExoPranayama, an actuated environment that physically manifests users’ breathing in yoga. Through a series of trials with yoga practitioners and expert teachers, we explore its role in the practice of yoga. Our interview results reveal that biofeedback through the environment supported teaching and improved self-awareness, but it impacted group cohesion. Two practical uses of the technology emerged for supporting breath control in yoga: (1) biofeedback can provide new information about users’ current internal states; (2) machine-driven feedback provides users with a future state or goal and leads to improved cohesiveness.     

Creativity Bento Box: A Physical Resource Pack to Support Interaction in Virtual Space

The Creativity Bento Box is a physical resource pack, designed to support casual social interaction and break taking in an intensive, computer-mediated social activity. It was developed within the Creativity Greenhouse project, which piloted a mechanism to create research proposals and distribute funding at a distance. This involved facilitated phases of collaboration and competition over multiple days of computer-mediated work, where participants communicate and interact through a virtual world. During the iterative development process, the lack of time for socializing, the intense focus on virtual resources, and a lack of time spent away from the screen were reported as negative issues in feedback from participants. This article reports on the development of the Creativity Bento Box and how it helped to address these issues. By providing physical resources that contrasted with the properties of the virtual world, it supported people to socialize and take breaks from their primary activity, allowed them to include physical space and artifacts in their interactions, and provoked moves away from the otherwise intense focus on the computer. The article reflects on the roles of the Bento Box as a gift, in bridging between physical and virtual contexts, its higher suitability during the earlier phases of ideation and group development, and its perception by participants as something “framed.” Through this, we highlight the underexplored potential of using physical, offline resources as a means to solve difficulties in distanced social interactions.