Studying co-running avionic real-time applications on multi-core COTS architectures

International audienceFor the last decades, industries from the safety-critical domain have been using Commercial Off-The-Shelf (COTS) architectures despite their inherent runtime variability. To guarantee hard real-time constraints in such systems, designers massively relied on resource over-provisioning and disabling the features responsible for runtime variability. The recent shift to multi-core architectures in the embedded COTS market worsened the runtime variability problem as contention on shared hardware resources brought new variability sources. Additionally, hiding this variability in additional safety margins as performed in the past will offset most if not all the multi-core performance gains. To enable the use of multi-cores in this domain, it has become essential to finely characterize at system level the application workload, as well as the possible contention on shared hardware resources. In this paper, we introduce measurement techniques based on a set of dedicated stressing benchmarks and architecture hardware monitors to characterize (1) the architecture, by identifying the shared hardware resources and their associated contention mechanisms. (2) the application, by identifying which shared hardware resources it is sensitive to. Such information would guide us toward identifying which applications can run smoothly together without endangering individual worst-case execution times

Common Limitations of Image Processing Metrics:A Picture Story

While the importance of automatic image analysis is continuously increasing, recent meta-research revealed major flaws with respect to algorithm validation. Performance metrics are particularly key for meaningful, objective, and transparent performance assessment and validation of the used automatic algorithms, but relatively little attention has been given to the practical pitfalls when using specific metrics for a given image analysis task. These are typically related to (1) the disregard of inherent metric properties, such as the behaviour in the presence of class imbalance or small target structures, (2) the disregard of inherent data set properties, such as the non-independence of the test cases, and (3) the disregard of the actual biomedical domain interest that the metrics should reflect. This living dynamically document has the purpose to illustrate important limitations of performance metrics commonly applied in the field of image analysis. In this context, it focuses on biomedical image analysis problems that can be phrased as image-level classification, semantic segmentation, instance segmentation, or object detection task. The current version is based on a Delphi process on metrics conducted by an international consortium of image analysis experts from more than 60 institutions worldwide.Comment: This is a dynamic paper on limitations of commonly used metrics. The current version discusses metrics for image-level classification, semantic segmentation, object detection and instance segmentation. For missing use cases, comments or questions, please contact [email protected] or [email protected]. Substantial contributions to this document will be acknowledged with a co-authorshi

Aspects of mirrors and suspensions for advanced gravitational wave detectors

Gravitational waves were first predicted by Albert Einstein's Theory of general relativity, published in 1916. These waves are perturbations in the curvature of space-time. Indirect evidence of their existence has been obtained via observations of binary pulsar system inspirals by Hulse and Taylor. Research is now focussed on achieving direct detection of gravitational waves, giving a new way of observing astronoomical events in the universe. Gravitational waves are quadrupole in nature, causing tidal strains in space. The weak nature of gravity means that the magnitude of these strains is very small. Only astronomical scale sources are likely to produce waves of sufficient amplitude to be detected on Earth. In the frequency band of a few Hz to a few kHz, the expected strain amplitude for violent sources is of the order of 10[superscript -22]. Detection is most likely to be achieved using long baseline interferometer detectors. Currently several such detectors are in operation worldwide, including the GEO600 detector, built in a collaboration involving the Institute for Gravitational Research at the University of Glasgow, the Albert Einstein Institute (Hannover and Golm), and the University of Cardiff. In America the LIGO detector network has three large interferometric detectors - two of 4 km arm length and one with 2 km arms. In Italy a European collaboration has constructed the 3 km VIRGO detector. Currently GEO600 and LIGO have undertaken 5 data taking science runs with the most recent year long run, also involving VIRGO, concluding in November 2007. No detections have yet been confirmed, but analysis on the results of the most recent GEO600/LIGO/VIRGO run is ongoing. These detectors are now operating at, or close to their design sensitivities, so research is focussed on reduction of various noise sources by upgrading of the detectors. One important noise source is thermal noise (both Brownian and thermo-elastic) - a limiting factor at midband frequencies. Reduction of mechanical loss in mirrors and their suspensions will help lessen the impact of thermal noise in future detectors. The research detailed in this thesis was aimed at reducing thermal noise. In particular, it covers work undertaken to investigate the mechanical loss of suspension ribbons and fibres, test mass mirror coatings and also diffractive surfaces on test masses to evaluate their suitability for employment in future advanced gravitational wave detectors. Upgrade of LIGO to "Advanced LIGO" will aim to reduce thermal noise by implementing mirror suspension techniques pioneered in GEO600. Specifically, it was initially proposed that test masses be suspended from silica ribbon fibres, a key choice that will be re-evaluated in this thesis. Ribbons (or fibres) will be fabricated by a CO[subscript 2] laser pulling machine being developed in Glasgow, with control programming being undertaken by the author. Characterising the dimensions, strength and vertical bounce frequencies of the ribbons is important to confirm their suitability for use in detector mirror suspensions. A dimensional characterisation machine was constructed to measure the ribbon's cross sectional dimensions, with emphasis being placed on achieving high resolution in the ribbon neck regions, where the most bending occurs. Also, a bounce testing machine was constructed to experimentally measure the ribbon's vertical bounce frequency. Finally a proof load test was constructed to verify that ribbons could support the required weight. Results showed that ribbons could be fabricated successfully with the required strength and bounce frequency, though shaping of the cross section still requires further research to achieve the optimum. In a pendulum system most of the energy is stored as gravitational potential energy rather than bending energy of the suspension fibres or ribbons. Thus the effective loss of the suspension fibres/ribbons is reduced or "diluted" and thermal noise is lower than may be naively expected. Dilution of the mechanical loss of the pendulum suspensions was investigated using finite element modelling. Methods for importing data from the dimensional characterisation machine were developed, and it was observed that the dilution resulting from ribbon suspensions was not as high as had been initially expected, with bending in the neck region of the ribbon being seen to significantly reduce dilution. It was observed that the rectangular ribbons had inferior dilution to equivalent cross section circular fibres for necks of the length typically being produced. A typical 7.5 mm necked ribbon was seen to have a dilution 1.5 times lower than an equivalent fibre, despite the ribbons having 3.3 times greater dilution with no necks. Ribbons were only seen to have this superior dilution for very short necks. Bending in the necks resulted in an increased amount of bending strain energy occurring which caused the lower dilution factors. Additionally, bending occurring in the ears that join the fibres or ribbons to the masses was seen to further reduce the dilution. In the light of low dilution factors, reduction (ideally nulling) of thermoelastic noise was studied. Reduction in thermal noise in this way is proposed through the use of tapered fibres, which showed that a lower overall noise level than that from the baseline ribbons planned for Advanced LIGO can be achieved, despite lower dilution factors. In the light of this work tapered fibres have now been adopted as the baseling for Advanced LIGO. Measurement of test mass mirror samples showed that the mechanical loss of mirror coatings can be significantly reduced by doping the high refractive index layer, with reduction up to a factor of 2.5 in measured mechanical loss observed, when compared to equivalent undoped coatings. In order to perform these measurements an interferometric read out system was constructed. Future detectors will use higher laser powers which may cause thermal distortions in transmissive optical components. Use of all reflective components may be required to reduce this problem, possibly via diffractive mirrors. Measurements were undertaken on samples to discover if introducing a diffraction grating to an optic's surface increased the mechanical loss. However, the grating was not seen to do this, and also did not increase the mechanical loss of an optical coating applied on top of its surface, which verified that diffractive optics are viable for use in future detectors

Toddler music: a socio-cultural/historical examination of the musical development of two-year-olds and their carers in a child development laboratory classroom

The purpose of this study was to describe the music and musical practices two-year-olds, their caregivers, and I chose to purposefully engage in together, how this engagement reflected what was valued in various communities of practice they participated in in daily life, how this engagement reflected what music and musical practices they had access to, how access was given or obtained, and the ways musical practice was transformed in an early childhood classroom through mutual participation and negotiation of cultural meanings. The theoretical framework of this study is provided by the socio-cultural/historical learning theories of Barbara Rogoff (Transformation of Participation Perspective), Jean Lave and Etienne Wenger (Situated Learning, Peripheral Participation, and Communities of Practice), as well as Lev Vygotsky (The Historical Child) and Jerome Bruner (Humans Predisposition to Culture). The following research questions were investigated: 1. How do the members of a two-year-old Child Development Laboratory (CDL) classroom share, negotiate, and transform musical understanding and activity through participation in a musical community of practice? 2. What are the cultural meanings behind what is shared and how are these meanings negotiated and transformed? 3. How do values and access influence what is shared, negotiated, and transformed musically in this CDL classroom? 4. What musical understandings and activities are brought into the CDL classroom and how are these musical understandings and activities shared, negotiated, and transformed? iii An interpretive, ethnographic research methodology was employed. Complete observer, observer participant, and participant observer data generation methods were employed through generating field notes and video recordings over five months in an intact classroom of two-year-olds and their teachers in an early childhood center housed at a large Midwestern university. Interviews with 10 parents, two teachers, and the associate director of the center were also conducted. Codes were developed that described the development of rapport between myself and the participants, the sociocultural aspects of the musical play the children, teachers, and myself engaged in alone and together, and personal and communal recurrences that centered on musical activity between participants. Four themes related to theories of sociocultural development that formed the conceptual framework of the study were observed during the data generation process. 1. Music play occurred when singing, recorded music, and musical instruments were introduced into play. 2. Music play involving singing, recorded music, and playing instruments transformed activity. 3. Music play that was introduced into activity was altered and expanded upon by the introduction of others’ ideas. 4. The participants understood why I was there and because of this interacted with me with musical intention during play. iv Four themes related to how spontaneous music play changed and was changed by sociocultural interactions among the participants emerged from analysis of the data. These included: 1. Spontaneous music play was the result of intentional acts between participants. 2. Spontaneous music play was the result of intersubjectivity between participants. 3. Spontaneous music play was the result of neural fabulation. 4. Spontaneous music play became recurrent through the development of a musical “We.” Implications for research and pedagogy in early childhood education were identified for early childhood educators, music educators interested in early childhood music education, and music educators who work with early childhood educators. These implications focus on the nature of spontaneity in daily sociocultural interactions through music play in early childhood settings

Columns Fall 2007

Features the article A Look at Creation . Ten pages devoted to exploring our origins. Find out how students and faculty interact with the elements of creation in our opening feature, 7 Days: 6,000 Years Later. Learn how Southern studies the topic of creation in Old Debate Studied in New Ways,\u27 and listen to biology professors share their viewpoints in The Creation Question and What About Dinosaurs?https://knowledge.e.southern.edu/alumni_newsletter/1163/thumbnail.jp

Tangible user interfaces : past, present and future directions

In the last two decades, Tangible User Interfaces (TUIs) have emerged as a new interface type that interlinks the digital and physical worlds. Drawing upon users' knowledge and skills of interaction with the real non-digital world, TUIs show a potential to enhance the way in which people interact with and leverage digital information. However, TUI research is still in its infancy and extensive research is required in or- der to fully understand the implications of tangible user interfaces, to develop technologies that further bridge the digital and the physical, and to guide TUI design with empirical knowledge. This paper examines the existing body of work on Tangible User In- terfaces. We start by sketching the history of tangible user interfaces, examining the intellectual origins of this field. We then present TUIs in a broader context, survey application domains, and review frame- works and taxonomies. We also discuss conceptual foundations of TUIs including perspectives from cognitive sciences, phycology, and philoso- phy. Methods and technologies for designing, building, and evaluating TUIs are also addressed. Finally, we discuss the strengths and limita- tions of TUIs and chart directions for future research

XR, music and neurodiversity: design and application of new mixed reality technologies that facilitate musical intervention for children with autism spectrum conditions

This thesis, accompanied by the practice outputs,investigates sensory integration, social interaction and creativity through a newly developed VR-musical interface designed exclusively for children with a high-functioning autism spectrum condition (ASC).The results aim to contribute to the limited expanse of literature and research surrounding Virtual Reality (VR) musical interventions and Immersive Virtual Environments (IVEs) designed to support individuals with neurodevelopmental conditions. The author has developed bespoke hardware, software and a new methodology to conduct field investigations. These outputs include a Virtual Immersive Musical Reality Intervention (ViMRI) protocol, a Supplemental Personalised, immersive Musical Experience(SPiME) programme, the Assisted Real-time Three-dimensional Immersive Musical Intervention System’ (ARTIMIS) and a bespoke (and fully configurable) ‘Creative immersive interactive Musical Software’ application (CiiMS). The outputs are each implemented within a series of institutional investigations of 18 autistic child participants. Four groups are evaluated using newly developed virtual assessment and scoring mechanisms devised exclusively from long-established rating scales. Key quantitative indicators from the datasets demonstrate consistent findings and significant improvements for individual preferences (likes), fear reduction efficacy, and social interaction. Six individual case studies present positive qualitative results demonstrating improved decision-making and sensorimotor processing. The preliminary research trials further indicate that using this virtual-reality music technology system and newly developed protocols produces notable improvements for participants with an ASC. More significantly, there is evidence that the supplemental technology facilitates a reduction in psychological anxiety and improvements in dexterity. The virtual music composition and improvisation system presented here require further extensive testing in different spheres for proof of concept

Volume 61, Number 09 (September 1943)

When Walt Whitman was a Music Critic How to Become a Better Pianist (interview with Jan Smeterlin) Opera for the Millions: An Analysis of the Popularity of Opera (interview with Milton J. Cross) Use the Mirror in Voice Study Claude Debussy, French Patriot Musicians in Khaki: A Vision of Victory in Music Thrills Britain\u27s Armies: The Amazing Story of Symphony Orchestras Made Up of Officers and Men Among the Composers Fundamentals of Good Breathing Natural Power in Piano Playing Roses and Thorns in the Path of Private Teaching Grieg—Nationalist and Cosmopolitan: Personal Recollections of Edvard Grieg, Part 4 Three T\u27s: Technique—Tradition—Typing the Artist (interview with Erich Leinsdorf) Why Don\u27t You Like Modern Music? Music of Iceland Technic of the Month—Minuet in E-flat Major by W.A. Mozarthttps://digitalcommons.gardner-webb.edu/etude/1223/thumbnail.jp