Cheating prevention in linear secret sharing

Cheating detection in linear secret sharing is considered. The model of cheating extends the Tompa-Woll attack and includes cheating during multiple (unsuccessful) recovery of the secret. It is shown that shares in most linear schemes can be split into subshares. Subshares can be used by participants to trade perfectness of the scheme with cheating prevention. Evaluation of cheating prevention is given in the context of different strategies applied by cheaters.

Distinguishing attack on SOBER-128 with linear masking

We present a distinguishing attack against SOBER-128 with linear masking. We found a linear approximation which has a bias of 2^− − 8.8 for the non-linear filter. The attack applies the observation made by Ekdahl and Johansson that there is a sequence of clocks for which the linear combination of some states vanishes. This linear dependency allows that the linear masking method can be applied. We also show that the bias of the distinguisher can be improved (or estimated more precisely) by considering quadratic terms of the approximation. The probability bias of the quadratic approximation used in the distinguisher is estimated to be equal to O(2^− − 51.8), so that we claim that SOBER-128 is distinguishable from truly random cipher by observing O(2^103.6) keystream words.

Topological design and modulation strategy for buck-boost three-level inverters

To date, designed topologies for DC-AC inversion with both voltage-buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable buck-boost three-level inverters that can also support bidirectional power conversion. The proposed front-end circuitry is developed from the Cuk-derived buck-boost two-level inverter, and by using the "alternative phase opposition disposition" (APOD) modulation scheme, the buck-boost three-level inverters can perform distinct five-level line voltage and three-level phase voltage switching by simply controlling the active switches located in the designed voltage boost section of the circuits. As a cost saving option, one active switch can further be removed from the voltage-boost section of the circuits by simply re-routing the gating commands of the remaining switches without influencing the ac output voltage amplitude. To verify the validity of the proposed inverters, Matlab/PLECS simulations were performed before a laboratory prototype was implemented for experimental testing.

Topological design and modulation strategy for buck-boost three-level inverters

To date, designed topologies for DC-AC inversion with both voltage buck and boost capabilities are mainly focused on two-level circuitries with extensions to three-level possibilities left nearly unexplored. Contributing to this area of research, this paper presents the design of a number of viable buck-boost three-level inverters that can also support bidirectional power conversion. The proposed front-end circuitry is developed from the Cuk-derived buck-boost two-level inverter, and by using the ldquoalternative phase opposition dispositionrdquo modulation scheme, the buck-boost three-level inverters can perform distinct five-level line voltage and three-level phase voltage switching by simply controlling the active switches located in the designed voltage boost section of the circuits. As a cost saving option, one active switch can further be removed from the voltage boost section of the circuits by simply rerouting the gating commands of the remaining switches without influencing the AC output voltage amplitude. To verify the validity of the proposed inverters, MATLAB/PLECS simulations were performed before a laboratory prototype was implemented for experimental testing.

A linear-elastic model of anisotropic tumour growth

This paper examines the effect of anisotropic growth on the evolution of mechanical stresses in a linear-elastic model of a growing, avascular tumour. This represents an important improvement on previous linear-elastic models of tissue growth since it has been shown recently that spatially-varying isotropic growth of linear-elastic tissues does not afford the necessary stress-relaxation for a steady-state stress distribution upon reaching a nutrient-regulated equilibrium size. Time-dependent numerical solutions are developed using a Lax-Wendroff scheme, which show the evolution of the tissue stress distributions over a period of growth until a steady-state is reached. These results are compared with the steady-state solutions predicted by the model equations, and key parameters influencing these steady-state distributions are identified. Recommendations for further extensions and applications of this model are proposed.

Networking iPads into Preschool Spaces

This chapter explores preschools as networked spaces into which iPads were introduced, which involved the mediation of complex relationships between children and adults, physical and virtual technology and other materials like toys, play spaces, art materials and books. The chapter aims to explain how these human and non-human ‘actors’ come to coexist and lead to the development of literacy and creativity in specific ways. This approach particularly draws attention to specific challenges faced by the teachers as they negotiated a range of complex demands and obstacles to make the iPads available to the children for play and learning.

Art spaces in community and economic development : connections to neighborhoods, artists, and the cultural economy

There is growing interest in the arts in community and economic development, yet little research examines the dynamics of community-based arts institutions to inform urban planning and policy. Drawing on interviews with participants and organizers of small and midsized art spaces, the study explores the factors that influence their involvement in neighborhood revitalization and outreach, support for artistic communities, and efforts to build bridges to commercial cultural sectors. Art spaces function as a conduit for building social networks that contribute to both community revitalization and artistic development. But issues pertaining to the location, organization, and management of art spaces may limit their community and economic development potential. The article concludes with proposals to craft stronger arts-based community and economic development programs.

Art spaces, public space, and the link to community development

Recent literature credits community art spaces with both enhancing social interaction and engagement and generating economic revitalization. This article argues that the ability of art spaces to realize these outcomes is linked to their role as public spaces and that their community development potential can be expanded with greater attention to this role. An analysis of the public space characteristics is useful because it encourages consideration of sometimes overlooked issues, particularly the effect of the physical environment on outcomes related to community development. I examine the relationship between public space and community development at various types of art spaces including artist cooperatives, ethnic-specific art spaces, and city-sponsored art centers in central city and suburban locations. This study shows that through their programming and other activities, art spaces serve various public space roles related to community development. However, the ability of many to perform as public spaces is hindered by facility design issues and poor physical connections in their surrounding area. This article concludes with proposals for enhancing the community development role of the art spaces through their function as public spaces.

Designing schools as effective 21st C learning spaces : a review

The Queensland Centre for Social Science Innovation was formed in 2012 to develop collaborations among the Queensland Government and five Queensland universities—The University of Queensland, Griffith University, Queensland University of Technology, James Cook University and Central Queensland University. Three priorities for initial projects were established by the Queensland Government with response by the participating universities. This project addressed the identified priority area: factors affecting educational achievement and investigation of the link between school design, refurbishment and educational outcomes. The proposal for this project indicated that a Review of research literature would be undertaken that linked school and classroom design with educational outcomes for learners in the 21st century. Further, research would be examined for impact of technology on staff and students, as well as learning spaces that addressed the diversity of student learners. Specific investigation of research on effective design to enhance learning outcomes for Aboriginal and Torres Strait Islander students was to be undertaken. The project therefore consists of a Review of research literature to provide an evidence base on the impact of school and classroom on educational outcomes. The original proposal indicated that indicators of successful school and classroom design would be student learning outcomes on a range of variables, with input, the specific architectural design elements. The review was undertaken during the period July 2012 to June 2013. A search was undertaken of journals, databases, and websources to identify relevant material. These were examined for evidence-based statements and design of learning spaces to enhance learning. The Review is comprehensive, and representative of issues raised in research, and conceptualisations and debates informing modern educational design. Initial findings indicated two key findings central to reading this Review. The first key finding is that the predominant focus of modern design of learning space is on process and the engagement of stakeholders. Schools are social institutions and development of a school as a learning space to suit 21st century learning needs necessarily involves the staff, students and other members of the community as key participants. The concept of social aspects of design is threaded throughout the Review. The second key finding is that little research explicitly examined the relationship between the design of learning spaces and educational outcomes. While some research does exist, the most explicitly-focused research uses narrow test-based achievement as the learning outcomes. These are not sympathetic to the overall framings of the research on 21st century learning, future schooling and the needs of the new generation of learners and society.

Art Spaces, Art Places : Examining Neighborhood Preferences of New York Arts Organizations

This report builds on and extends a diverse literature that examines the location patterns of the arts and creative industries through analysis of a database of arts nonprofit organizations from the New York State Cultural Data Project. We confirm the link between arts organizations and the urban core and creative economy, but challenge the assumption that arts tend to locate in ethnic and disadvantaged neighborhoods. By identifying key neighborhood attributes associated with distinct types of arts organizations, we can better identify potential sites conducive to nurturing additional artistic activity and inform strategies to engage organizations in neighborhoods that are underserved in the arts.

The Habitual Rhythms of Becoming-Involved: Insights into Participation Experiences in Urban Spaces by Children with Diverse Mobility

This chapter reports on a study that reveals the essence of participation in urban spaces by ten children who live with various physical conditions: Muscular Dystrophy, Cerebral Palsy, and Autoimmune Rheumatic Diseases. These conditions affect muscle and movement differently resulting in diverse ways in which children move through space (personal mobility). The children at the time of the research were 9-12 years of age residing in South-east Queensland, Australia. The approach and methods selected for this study, interpretive phenomenological inquiry and grounded theory, were chosen for their capacity to capture the complexity and multiple interactions of the child’s urban living. The confronting and poignant accounts by children and their families of their experiences produced a new way of understanding the concept of participation, as a ‘journey of becoming involved.’ Their accounts of performing everyday routines (e.g. leaving home, getting in and out of the car, and entering places) in urban spaces (neighbourhood streets, schools, open spaces, shopping centres, and hospitals) revealed differences in the way settings were experienced. These differences were associated with the interplay between the body, space and context. Where interplays were problematic, explicit decisions about children’s involvement were made. These decisions were described in terms of ‘avoid going’, ‘pick and choose’, ‘discontinue’, ‘accept’, or ‘contest.’ What these decisions mean is some spaces are avoided, some journeys are discontinued, and some barriers encountered in journeys are normalised as everyday experiences, i.e. ‘tolerable discrimination’. These actions resulted in experiences of non-participation or partial–tokenistic participation. The key substantive contribution of the research lies in the identification of points in children’s journeys that shape participation experience. These points identify where future interventions in policy, programming and design can be made to make real and sustaining changes to lives of children and their families in geographies crucial to urban living.

An adaptive appearance-based map for long-term topological localization of mobile robots

"This work considers a mobile service robot which uses an appearance-based representation of its workplace as a map, where the current view and the map are used to estimate the current position in the environment. Due to the nature of real-world environments such as houses and offices, where the appearance keeps changing, the internal representation may become out of date after some time. To solve this problem the robot needs to be able to adapt its internal representation continually to the changes in the environment. This paper presents a method for creating an adaptive map for long-term appearance-based localization of a mobile robot using long-term and short-term memory concepts, with omni-directional vision as the external sensor."--publisher website

Surface reconstruction of wheat leaf morphology from three-dimensional scanned data

Realistic virtual models of leaf surfaces are important for a number of applications in the plant sciences, such as modelling agrichemical spray droplet movement and spreading on the surface. In this context, the virtual surfaces are required to be sufficiently smooth to facilitate the use of the mathematical equations that govern the motion of the droplet. While an effective approach is to apply discrete smoothing D2-spline algorithms to reconstruct the leaf surfaces from three-dimensional scanned data, difficulties arise when dealing with wheat leaves that tend to twist and bend. To overcome this topological difficulty, we develop a parameterisation technique that rotates and translates the original data, allowing the surface to be fitted using the discrete smoothing D2-spline methods in the new parameter space. Our algorithm uses finite element methods to represent the surface as a linear combination of compactly supported shape functions. Numerical results confirm that the parameterisation, along with the use of discrete smoothing D2-spline techniques, produces realistic virtual representations of wheat leaves.

Topological localization using optical flow descriptors

We propose a topological localization method based on optical flow information. We analyse the statistical characteristics of the optical flow signal and demonstrate that the flow vectors can be used to identify and describe key locations in the environment. The key locations (nodes) correspond to significant scene changes and depth discontinuities. Since optical flow vectors contain position, magnitude and angle information, for each node, we extract low and high order statistical moments of the vectors and use them as descriptors for that node. Once a database of nodes and their corresponding optical flow features is created, the robot can perform topological localization by using the Mahalanobis distance between the current frame and the database. This is supported by field trials, which illustrate the repeatability of the proposed method for detecting and describing key locations in indoor and outdoor environments in challenging and diverse lighting conditions.

The sideways hourglass : establishing the lemniscate as a narrative structure for writing and reading non-linear stories

This thesis is a study in narratology that examines the pre-theoretical ideas that underlie the study of narrative and time. The thesis explores how the lemniscate can be transported from geometry to narrative in order to structure a non-linear story that breaks the rules of causality and chronology by coupling physical movement through space with the backward pull of memory. The findings offer new possibilities for understanding the nexus between shape and story and for recording non-linear narratives that are marked by simultaneity, counterpoint, and reversal.