Impact of ambient conditions on SMP elimination and rejection in MBRs

The widespread application of the membrane-assisted activated sludge process is restricted by membrane fouling, which increases investment and operating costs. Soluble microbial products (SMPs) are currently considered as the major cause of membrane fouling in membrane bioreactors (MBRs). This study aims at elucidating and quantifying the effects of varying environmental conditions on SMP elimination and rejection based on findings in a pilot MBR and in well-defined lab trials. Several factors are thought to influence the concentration of SMP and their fouling propensity in one way or the other, but findings are often inconsistent or even contradictory. Here, SMP loading rate was found to have the greatest effect on SMP elimination and thus on concentration in the MBR. The degree of elimination decreased at very low DO and low nitrate concentrations. On average, 75% of influent SMP were eliminated in both pilot and lab trials, with the elimination of polysaccharides (PS) mostly above 80%. Rejection of SMP components by the used membrane (PAN, 37nm) ranged mainly from 20% to 70% for proteins and from 75% to 100% for PS. Especially protein rejection decreased at higher temperatures and higher nitrification activity. The increased fouling rates at lower temperatures might therefore partly be explained by this increased rejection. Apparently, mainly the nitrite-oxidising community is responsible for the formation for smaller SMP molecules that can pass the membrane.     

Increasing Workplace Independence for People with Cognitive Disabilities by Leveraging Distributed Cognition among Caregivers and Clients

This paper describes a group configuration that is currently employed to support the everyday living and working activities of people with cognitive disabilities. A client receiving face-to-face, often one-to-one, assistance from a dedicated human job coach is characteristic of this traditional configuration. We compare it with other group configurations that are used in cooperative and distributed work practices and propose an alternative configuration titled active distributed support system. In so doing, we highlight requirements that are unique to task support for people with cognitive disabilities. In particular, we assert that the knowledge of how to perform such activities is shared not only among people, but also between people and artifacts. There is a great potential for innovative uses of ubiquitous and mobile technologies to support these activities. A survey of technologies that have been developed to provide these individuals with greater levels of independence is then presented. These endeavors often attempt to replace human job coaches with computational cognitive aids. We discuss some limitations of such approaches and present a model and prototype that extends the computational job coach by incorporating human caregivers in a distributed one-to-many support system.     

Toward the complexity of the existence of wonderfully stable partitions and strictly core stable coalition structures in enemy-oriented hedonic games

We study the computational complexity of the existence and the verification problem for wonderfully stable partitions (WSPE and WSPV) and of the existence problem for strictly core stable coalition structures (SCSCS) in enemy-oriented hedonic games. In this note, we show that WSPV is NP-complete and both WSPE and SCSCS are DP-hard, where DP is the second level of the boolean hierarchy, and we discuss an approach for classifying the latter two problems in terms of their complexity.     

Kundenfreundlichkeit von Musik-Downloadplattformen?

Im Wege einer ?konomischen Analyse wird die Kundenfreundlichkeit marktg?ngiger Downloadportale untersucht. Es ergibt sich, dass — bei zahlreichen Unterschieden im Detail — alle untersuchten Downloadplattformen dem traditionellen Gesch?ftsmodell der Offline-Welt folgen und Musikstücke gegen Bezahlung anbieten. Verbesserungsm?glichkeiten im Hinblick auf die Kundenfreundlichkeit konnten bei allen Plattformen gefunden werden. Weitergehende Gestaltungsoptionen des Onlinevertriebs — von innovativen Erl?squellen bis hin zu einer Abkehr von der Vorstellung, das Datenobjekt sei das ?konomische Gut — bleiben ungenutzt.     

Identifying requirements for communication support: A maturity grid-inspired approach

Communication is a critical success factor in design. It can be seen as the social and cognitive process by which information is selected, messages are exchanged between interacting partners, and meaning is created. How communication processes can best be captured, analysed and assessed, as a preliminary step toward suggestions for improvement of communication practices, remains a challenge for researchers and practitioners. To this end, a maturity grid-inspired approach to audit communication practices has been developed. This paper employs a maturity grid approach and reflects critically on the construction and application of the approach in a structured group workshop in software design. Such an approach yields dual benefits: (a) as a research method to gather insight into communication and (b) as a guide to plan improvements in practice. Conclusions are drawn for the process of auditing communication in design.     

Seeds of Cross-Media Production

We present an empirical study of an organization that has recently moved from traditional newspaper production towards cross-media production involving the integrated digital production of newspaper, television, radio and web-news. The paper focuses on the daily production rhythms of the media separately and of cross-media production. Since cross-media production is in the making, we study the instruments currently used for planning and coordination, and analyze them as seeds that will eventually make cross-media production happen. Time and timing are important in news production in general, and our analyses focus on the rhythm of the daily planning, coordination and production processes. Specifically, we analyze the temporal coordination of the activities in and around the Superdesk – the current center of coordination of the news organization, and of the persons who work specifically with planning and coordination. We demonstrate how the production rhythms of the individual media collide with that of cross-media, and how product lifecycle rhythms add to the list of causes of problems that may jeopardize cross-media production. We propose to strengthen planning and overview support elements of the Superdesk, and the main new coordinator role of the organization. We point out how the media rhythms of newspaper in particular must be backgrounded. To achieve cross-media production, the starting point must be to strengthening and developing further the cross-media rhythms, rather than supplementing individual media rhythms.

A mobile VR-based respiratory biofeedback game to foster diaphragmatic breathing

Virtual reality (VR) has become popular in mental health research. Several studies have explored the use of VR in the context of biofeedback protocols. In the present paper, we report on the development and evaluation of a VR-based respiratory biofeedback game to foster diaphragmatic breathing. The game integrates respiratory biofeedback, restorative VR and gamification. The game is designed to run on a mobile, all-in-one VR headset. Notably, an integrated VR hand controller is utilized as a sensor to detect respiration-induced movements of the diaphragm. In a longitudinal within-subjects study, we explored the feasibility of the game and tested the effectiveness of six training sessions. Participants reported a pleasant user experience. Moreover, the results show that the brief VR-based breathing training increased perceived breath awareness, improved diaphragmatic breathing, increased relaxation, decreased perceived stress, reduced symptoms of burnout and boosted relaxation-related self-efficacy. Future studies need to address the generalizability and long-term stability of the results, compare the approach with existing treatments and fine-tune the training components.

     

Contexts, work processes, and workspaces

In this paper a framework for the conceptual modelling of organizational contexts is provided and it is embodied into an extension of the TOSCA organizational handbook.The context of a work process is relevant since the effectiveness of the cooperation among its actors is highly dependent on their awareness of it. It requires, on the one hand, that the context is made available in terms of visibility and/or transparency; on the other, that at any time a selection is made so that only what is relevant to the context is provided, leaving the rest in the background. With respect to the first requirement a model of the organizational context is needed, so that all the information regarding its dimensions can be linked together. With respect to the second requirement, a work process model provides some guidelines for designing a system offering a selective access to the context of a work process. The workspace metaphor is a good paradigm to make that information ready at hand, since it is the natural framework within which people do their work.     

Impact of item density on the utility of visual context in magic lens interactions

This article reports on two user studies investigating the effect of visual context in handheld augmented reality interfaces. A dynamic peephole interface (without visual context beyond the device display) was compared to a magic lens interface (with video see-through augmentation of external visual context). The task was to explore items on a map and look for a specific attribute. We tested different sizes of visual context as well as different numbers of items per area, i.e. different item densities. Hand motion patterns and eye movements were recorded. We found that visual context is most effective for sparsely distributed items and gets less helpful with increasing item density. User performance in the magic lens case is generally better than in the dynamic peephole case, but approaches the performance of the latter the more densely the items are spaced. In all conditions, subjective feedback indicates that participants generally prefer visual context over the lack thereof. The insights gained from this study are relevant for designers of mobile AR and dynamic peephole interfaces, involving spatially tracked personal displays or combined personal and public displays, by suggesting when to use visual context.     

An Effective Algorithm for the Futile Questioning Problem

In the futile questioning problem, one must decide whether acquisition of additional information can possibly lead to the proof of a conclusion. Solution of that problem demands evaluation of a quantified Boolean formula at the second level of the polynomial hierarchy. The same evaluation problem, called Q-ALL SAT, arises in many other applications. In this paper, we introduce a special subclass of Q-ALL SAT that is at the first level of the polynomial hierarchy. We develop a solution algorithm for the general case that uses a backtracking search and a new form of learning of clauses. Results are reported for two sets of instances involving a robot route problem and a game problem. For these instances, the algorithm is substantially faster than state-of-the-art solvers for quantified Boolean formulas.