Relative entropy rate based model selection for linear hybrid system filters of uncertain nonlinear systems

Hybrid system representations have been exploited in a number of challenging modelling situations, including situations where the original nonlinear dynamics are too complex (or too imprecisely known) to be directly filtered. Unfortunately, the question of how to best design suitable hybrid system models has not yet been fully addressed, particularly in the situations involving model uncertainty. This paper proposes a novel joint state-measurement relative entropy rate based approach for design of hybrid system filters in the presence of (parameterised) model uncertainty. We also present a design approach suitable for suboptimal hybrid system filters. The benefits of our proposed approaches are illustrated through design examples and simulation studies.

Shear tests of lipped chanel beams with web openings

Cold-formed steel members are increasingly used as primary structural elements in the building industries around the world due to the availability of thin and high strength steels and advanced cold-forming technologies. Cold-formed steel lipped channel beams (LCB) are commonly used as flexural members such as floor joists and bearers. However, their shear capacities are determined based on conservative design rules. Current practice in flooring systems is to include openings in the web element of floor joists or bearers so that building services can be located within them. However, limited research has been undertaken on the shear behaviour and strength of LCBs with web openings. Hence a detailed experimental study involving 32 shear tests was undertaken to investigate the shear behaviour and strength of LCBs with web openings. Simply supported test specimens of LCBs with an aspect ratio of 1.0 and 1.5 were loaded at mid-span until failure. This paper presents the details of this experimental study and the results of their shear capacities and behavioural characteristics. Experimental results showed that the current design rules in cold-formed steel structures design codes are very conservative for the shear design of LCBs with web openings. Improved design equations have been proposed for the shear strength of LCBs with web openings based on the experimental results from this study.

Shear buckling characteristics of cold-formed steel channel beams

Cold-formed steel members are increasingly used as primary structural elements in the building industries around the world due to the availability of thin and high strength steels and advanced cold-forming technologies. Cold-formed lipped channel beams (LCB) are commonly used as flexural members such as floor joists and bearers. However, their shear capacities are determined based on conservative design rules. For the shear design of LCB web panels, their elastic shear buckling strength must be determined accurately including the potential post-buckling strength. Currently the elastic shear buckling coefficients of LCB web panels are determined by assuming conservatively that the web panels are simply supported at the junction between their flange and web elements. Hence finite element analyses were conducted to investigate the elastic shear buckling behavior of LCBs. An improved equation for the higher elastic shear buckling coefficient of LCBs was proposed based on finite element analysis results and included in the ultimate shear capacity equations of the North American cold-formed steel codes. Finite element analyses show that relatively short span LCBs without flange restraints are subjected to a new combined shear and flange distortion action due to the unbalanced shear flow. They also show that significant post-buckling strength is available for LCBs subjected to shear. New equations were also proposed in which post-buckling strength of LCBs was included.

Teaching and learning family and consumer sciences through K-W-L charts

While much of the control and many of the activities found in today’s classrooms have been placed in the hands of the learners and learning has become inquiry-based, there remains a need for teachers to use teaching tools that would facilitate this student-centered teaching process. This article identifies the K-W-L Chart as one such tool and follows a case study of four Kuwaiti ‘Family and Consumer Sciences’ teaching / learning events to evaluate their ability to enhance the learning outcomes of eight students. The research was designed from a qualitative, multi-tiered design approach and was assessed through a constant comparative method of data analysis of interview responses, classroom observations and worksheet-assessments. The results showed that the use of K-W-L Charts influenced the teachers and learners toward a more inquiry-based approach and facilitated a more student-centered and collaborative learning environment, raising the level of interest and the amount of personal input given by the students.

Cold-formed steel columns subject to local buckling at elevated temperatures

Fire safety design of building structures has received greater attention in recent times due to continuing losses of properties and lives in fires. However, the structural behaviour of thin-walled cold-formed steel columns under fire conditions is not well understood despite the increasing use of light gauge steels in building construction. Cold-formed steel columns are often subject to local buckling effects. Therefore a series of laboratory tests of lipped and unlipped channel columns made of varying steel thicknesses and grades was undertaken at uniform elevated temperatures up to 700°C under steady state conditions. Finite element models of the tested columns were also developed, and their elastic buckling and nonlinear analysis results were compared with test results at elevated temperatures. Effects of the degradation of mechanical properties of steel with temperature were included in the finite element analyses. The use of accurately measured yield stress, elasticity modulus and stress-strain curves at elevated temperatures provided a good comparison of the ultimate loads and load-deflection curves from tests and finite element analyses. The commonly used effective width design rules and the direct strength method at ambient temperature were then used to predict the ultimate loads at elevated temperatures by using the reduced mechanical properties. By comparing these predicted ultimate loads with those from tests and finite element analyses, the accuracy of using this design approach was evaluated.

Experimental studies of the shear behaviour and strength of lipped channel beams with web openings

Cold-formed steel members are increasingly used as primary structural elements in the building industries around the world due to the availability of thin and high strength steels and advanced cold-forming technologies. Cold-formed lipped channel beams (LCB) are commonly used as flexural members such as floor joists and bearers. However, their shear capacities are determined based on conservative design rules. Current practice in flooring systems is to include openings in the web element of floor joists or bearers so that building services can be located within them. Shear behaviour of LCBs with web openings is more complicated while their shear strengths are considerably reduced by the presence of web openings. However, limited research has been undertaken on the shear behaviour and strength of LCBs with web openings. Hence a detailed experimental study involving 40 shear tests was undertaken to investigate the shear behaviour and strength of LCBs with web openings. Simply supported test specimens of LCBs with aspect ratios of 1.0 and 1.5 were loaded at midspan until failure. This paper presents the details of this experimental study and the results of their shear capacities and behavioural characteristics. Experimental results showed that the current design rules in cold-formed steel structures design codes are very conservative for the shear design of LCBs with web openings. Improved design equations have been proposed for the shear strength of LCBs with web openings based on the experimental results from this study.

Heritage & habitus : designing to support situated, living knowledge

We refer to an ongoing endeavour aimed to assist Indigenouscommunities in Australian in persisting their personal and cultural memories linked to temporally dynamic interactions in situ. The design enables Indigenous users to upload items they collect themselves (e.g. photographs, audio, video) using mobile phones,in their traditional lands into a topographical simulation; and, thento associate these items with their own hand-drawn markings inthe simulation. The design responds to the rich interconnectedness between Indigenous culture and the land and the need to converge spatial information technologies with practices that are not, inherently, conditioned by the geometries of the West. We propose that the design approach contributes to thinking about ways that mobile guides can respond to multiple realities and corporeal and affective phenomena.

Vote with your feet : hyperlocal public polling for urban screens

Technological advances have led to an ongoing spread of public displays in urban areas. However, they still mostly show passive content such as commercials and digital signage. Researchers took notice of their potential to spark situated civic discourse in public space and have begun working on interactive public display applications. Attracting people’s attention and providing a low barrier for user participation have been identified as major challenges in their design. This thesis presents Vote With Your Feet, a hyperlocal public polling tool for urban screens allowing users to express their opinions. Similar to vox populi interviews on TV or polls on news websites, the tool is meant to reflect the mindset of the community on topics such as current affairs, cultural identity and local matters. It shows one Yes/No question at a time and enables users to vote by stepping on one of two tangible buttons on the ground. This user interface was introduced to attract people’s attention and to lower participation barriers. Vote With Your Feet was informed by a user-centred design approach that included a focus group, expert interviews and extensive preliminary user studies in the wild. Deployed at a bus stop, Vote With Your Feet was evaluated in a field study over the course of several days. Observations of people and interviews with 30 participants revealed that the novel interaction technology was perceived as inviting and that Vote With Your Feet can spark discussions among co-located people.

Being social @ work: designing for playfully mediated social awareness in work environments

Awareness within work environments should not be seen limited to important work-related information, activities and relationships. Mediating somewhat casual and engaging encounters related to non-work issues could also lead to meaningful and pleasurable experiences. This paper explores a design approach to support playfully mediated social awareness within an academic environment. Using ethnographic exploration and understanding the current and aspired practices, we provide details of two broad (and some times overlapping) categories of interaction for supporting and enhancing playfully mediated social awareness amongst staff members: 1) Self-Reflections and 2) Casual Encounters. We implement these two categories of interaction in an intelligent, asynchronous, large screen display called Panorama, for the staff room of our computer science department. Panorama attempts to mediate non-critical, non-work related information about the staff-members in an engaging manner to enhance social awareness within the department. We particularly emphasize on the soft design issues like reflections, belonging, care, pleasure and playfulness utilized in our design approach. The result of a two-phase assessment study suggests that our conceptualization of social awareness and the Panorama application has the potential to be easily incorporated into our academic environment.

STEM education for sustainable development : a sociotechnical analysis

It is debated that for sustainable STEM education and knowledge investment, human centered learning design approach is critical and important. Sustainability in this context is enduring maintenance of technological trajectories for productive economical and social interactions by demonstrating life critical scenarios through life critical system development and life experiences. Technology influences way of life and the learning and teaching process. Social software application development is more than learning of how to program a software application and extracting information from the Internet. Hence, our research challenge is, how do we attract learners to STEM social software application development? Our realisation processes begin with comparing Science and Technology education in developed (e.g., Australia) and developing (e.g., Sri Lanka) countries with distinction on final year undergraduates’ industry ready training programmes. Principal components analysis was performed to separate patterns of important factors. To measure behavioural intention of perceived usefulness and attitudes of the training, the measurement model was analysed to test its validity and reliability using partial least square (PLS) analysis of structural equation modelling (SEM). Our observation is that the relationship is more complex than we argue for. Our initial conclusions were that life critical system development and life experience trajectories as determinant factors while technological influences were unavoidable. A further investigation should involve correlations between human centered learning design approach and economical development in the long run.

On the operationalisation of conceptions of learning in higher education and their association with students’ knowledge and experiences of their learning

Conceptions of learning, as well as other associated aspects of prior knowledge, are theoretically important factors in influencing the manner in which the content and context of learning are engaged. The present study reports on: (a) the operationalisation of some of these factors aimed at isolating sources of explanatory variation that can be used for modelling purposes; and (b) a conservative exploration of the discriminatory power of, and exhibited patterns of association between, such sources of variation as have been isolated. Based on a conservative analytical approach, the results of the present study do not support a single clearly defined empirical model of conceptions of learning and associated constructs. Instead, there is consistent evidence that underlying empirical structures appear to be sensitive to the response context and other factors.

EnergyWiz

EnergyWiz is an Android smart phone application that was developed through a theory-driven design approach. Along with other features EnergyWiz provides users with three types of social comparison – normative, one-on-one and ranking.

Designing hubs for connected learning: social, spatial and technological insights from Coworking, Hackerspaces and Meetup groups

Connected learning, as a design approach, does not restrict learning to a dedicated learning space (school, university, etc.), but considers it to be an aggregation of individual experiences made through intrinsically motivated, active participation in and across various socio-cultural, every-day life environments. Urban places for meeting, interacting and connected learning with people from diverse backgrounds, cultures and areas of expertise are highly significant in the knowledge economy of our 21st century. However, little is yet known about best practices to design and curate such hubs that attract and support interest-driven and socially embedded learning experiences. The research study presented in this paper investigates design aspects that contribute to successful place-based spaces for connected learning. The paper reports findings from observations as well as interviews with users and managers of three different types of local, community-led learning environments, i.e., coworking spaces, hackerspaces, and meetup groups across Australia. The findings reveal social, spatial and technological interventions that these spaces apply to nourish a culture of connected learning, sharing and peer interaction. The discussion suggests a set of design implications for designers, managers and decision makers that have an interest in nourishing a connected learning culture among their user community.

Enhanced earth grid performance by improved conductor properties

Encroaching built environment with increased fault current levels is demanding a robust design approach and prolonged improved performance of the earth grid. With this in mind, the aim of the project was to perform a sensitivity analysis of the earth grid and an earthing performance evaluation with graphene coated conductors. Subsequent to these, a conceptual design to continuously monitor the performance of the earth grid was developed. In this study, earth grid design standards were compared to evaluate their appropriate use in determining the safety condition. A process to grow a thin film of graphene on the surface of cylindrical copper rods was developed to evaluate earthing performance in terms of conductivity and corrosion susceptibility.

Doing Digital Composition on the Social Web: Knowledge Processes in Literacy Learning

The power to influence others in ever-expanding social networks in the new knowledge economy is tied to capabilities with digital media production. This chapter draws on research in elementary classrooms to examine the repertoires of cross-disciplinary knowledge that literacy learners need to produce innovative digital media via the “social web”. It focuses on the knowledge processes that occurred when elementary students engaged in multimodal text production with new digital media. It draws on Kalantzis and Cope’s (2008) heuristic for theorizing “Knowledge Processes” in the Learning by Design approach to pedagogy. Learners demonstrate eight “Knowledge Processes” across different subject domains, skills areas, and sensibilities. Drawing data from media-based lessons across several classroom and schools, this chapter examines what kinds of knowledge students utilize when they produce digital, multimodal texts in the classroom. The Learning by Design framework is used as an analytic tool to theorize how students learn when they engaged in a specific domain of learning – digital media production.