696 research outputs found

    Barry Truax Riverrun (1986/2004), a case study from the TaCEM project, exploring new approaches to techniques of analysis and re-synthesis in the study of concert electroacoustic works

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    At last year’s EMS in Lisbon we introduced the TaCEM project (Technology and Creativity in Electroacoustic Music), a 30-month project funded by the UK’s Arts and Humanities Research Council, and demonstrated the generic TIAALS software being produced as part of this project. This year we present an update on the project, focusing particularly on the first of our case studies, Barry Truax’s Riverrun. Eight works have been selected for the project, taking into account criteria such as historical context, the nature of the synthesis techniques employed, and the aesthetics that have underpinned their realisation. Key considerations have included the accessibility of the technical resources and composing materials used in their production, and opportunities to pursue particular lines of enquiry with the composer concerned. In selecting the eight works for detailed study, a further consideration has been the extent to which the composers explored techniques that were already available at the time in ways that are unique and distinctive, or alternatively developed entirely new methods of synthesis in pursuit of their creative goals. The pioneering work of Barry Truax in terms of developing techniques of granular synthesis assign his achievements almost exclusively to the latter classification, and the composition of Riverrun (1986/2004) is a landmark achievement in this regard. Truax’s composing environment evolved from the early study of interactive real-time synthesis techniques at the Institute of Sonology, Utrecht 1971-73, exploring the possibilities of using Poisson-ordered distributions in the generation of microsound, to the emergence of entirely granular techniques at Simon Fraser University, British Columbia a decade later, culminating in the development of his program GSX designed specifically for waveform-based synthesis and first used to compose Riverrun, and its later extension, GSAMX, that extended these granular techniques to include the manipulation of previously sampled sound material. At the time of composition conventional minicomputers still lacked the capacity to generate multiple voices of granulated sound material in real time, but for Truax the acquisition in 1982 of a high speed bit slice array processor, the DMX-1000, provided the enhancedprocessing power necessary for achieving such a goal. The unique characteristics of its special hardware and associated programming environment, managed in turn via a host PDP 11/23 computer, both empowered his creative objectives and also materially shaped and influenced the ways in which they could be practically achieved. The significance of such causal relationships in the evolution of the electroacoustic music repertory has yet to be widely understood, and this study of Riverrun corroborates the importance of such a line of investigation. In this case it has been possible to carry out a detailed study of the original system, still maintained in working order by Truax, leading to a reconstruction of key elements of Riverrun using a Max-based simulation of GSX, the authenticity of the results being assessed both subjectively by means of a direct aural comparison and also measured objectively using software. Our presentation at this year’s EMS in Berlin included a demonstration of examples of the software we have developed to enable readers to engage with Riverrun interactively, both by analysing the original recordings and by using our emulation of the GSX system to be able to recreate passages of the work and manipulate the techniques employed in order to learn more about them. We also gave examples of other materials we have collected in relation to this case study, including videos of the composer himself working with the GSX system and discussing the composition of Riverrun

    Measurement of fault latency in a digital avionic miniprocessor

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    The results of fault injection experiments utilizing a gate-level emulation of the central processor unit of the Bendix BDX-930 digital computer are presented. The failure detection coverage of comparison-monitoring and a typical avionics CPU self-test program was determined. The specific tasks and experiments included: (1) inject randomly selected gate-level and pin-level faults and emulate six software programs using comparison-monitoring to detect the faults; (2) based upon the derived empirical data develop and validate a model of fault latency that will forecast a software program's detecting ability; (3) given a typical avionics self-test program, inject randomly selected faults at both the gate-level and pin-level and determine the proportion of faults detected; (4) determine why faults were undetected; (5) recommend how the emulation can be extended to multiprocessor systems such as SIFT; and (6) determine the proportion of faults detected by a uniprocessor BIT (built-in-test) irrespective of self-test

    An RF-Isolated Real-Time Multipath Testbed for Performance Analysis of WLANs

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    Real-time performance evaluation of wireless local area networks (WLANs) is an extremely challenging topic. The major drawback of real-time performance analysis in actual network installations is a lack of repeatability due to uncontrollable interference and propagation complexities. These are caused by unpredictable variations in the interference scenarios and statistical behavior of the wireless propagation channel. This underscores the need for a Radio Frequency (RF) test platform that provides isolation from interfering sources while simulating a real-time wireless channel, thereby creating a realistic and controllable radio propagation test environment. Such an RF-isolated testbed is necessary to enable an empirical yet repeatable evaluation of the effects of the wireless channel on WLAN performance. In this thesis, a testbed is developed that enables real-time laboratory performance evaluation of WLANs. This testbed utilizes an RF-isolated test system, Azimuthâ„¢ Systems 801W, for isolation from external interfering sources such as cordless phones and microwave ovens and a real-time multipath channel simulator, Elektrobit PROPSimâ„¢ C8, for wireless channel emulation. A software protocol analyzer, WildPackets Airopeek NX, is used to capture data packets in the testbed from which statistical data characterizing performance such as data rate and Received Signal Strength (RSS) are collected. The relationship between the wireless channel and WLAN performance, under controlled propagation and interference conditions, is analyzed using this RF-isolated multipath testbed. Average throughput and instantaneous throughput variation of IEEE 802.11b and 802.11g WLANs operating in four different channels - a constant channel and IEEE 802.11 Task Group n (TGn) Channel Models A, B, and C - are examined. Practical models describing the average throughput as a function of the average received power and throughput variation as a function of the average throughput under different propagation conditions are presented. Comprehensive throughput models that incorporate throughput variation are proposed for the four channels using Weibull and Gaussian probability distributions. These models provide a means for realistic simulation of throughput for a specific channel at an average received power. Also proposed is a metric to describe the normalized throughput capacity of WLANs for comparative performance evaluation

    2015 Electioneering Process and the Widening of Voters’ Political Consciousness

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    Electioneering process represents a formal procedure whereby a person is elected into a political office. Previous elections, in the political history of Nigeria, have recorded a high level of political apathy. Lack of interest, with reference to voters’ participation, has been a common political culture of the country. The massive rigging, recorded in previous elections, has led to the characterization of electioneering process by many Nigerians as “selection” instead of “election.” This ugly phenomenon has informed the growing voters’ political apathy recorded in the previous elections. This paper, therefore, raises some fundamental questions such as: when will an average Nigerian voter engage actively and consciously in the electioneering process and in the question of who becomes the leader in the country? How will the political confidence of an average Nigerian voter be restored? These passionate and mind-bugling questions have, however, been put to rest, following the just concluded 2015 electioneering process. Unlike the previous elections, which were marred generally by high level of voters’ apathy, the just concluded election marks a sharp deviation from the past, by ushering in an era of active political participants and a high level of political consciousness on the side of the electorate. Based on this, this paper, by means of historical hermeneutics/interpretation and philosophical analysis, argues that the just concluded 2015 electioneering process is a political eye-opener, in that it marked the beginning of a new era of active voters’ participation and in widening their political consciousness. Keywords: electioneering process, political apathy, political culture, political consciousness, political re-engineerin

    Personal development planning in the first year

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    The approach to quality and standards in higher education (HE) in Scotland is enhancement led and learner centred. It was developed through a partnership of the Scottish Funding Council (SFC), Universities Scotland, the National Union of Students in Scotland (NUS Scotland) and the Quality Assurance Agency for Higher Education (QAA) Scotland. The Higher Education Academy has also joined that partnership. The Enhancement Themes are a key element of a five-part framework, which has been designed to provide an integrated approach to quality assurance and enhancement. The Enhancement Themes support learners and staff at all levels in further improving higher education in Scotland; they draw on developing innovative practice within the UK and internationally The five elements of the framework are: z a comprehensive programme of subject-level reviews undertaken by higher education institutions (HEIs) themselves; guidance is published by the SFC (www.sfc.ac.uk) z enhancement-led institutional review (ELIR), run by QAA Scotland (www.qaa.ac.uk/reviews/ELIR) z improved forms of public information about quality; guidance is provided by the SFC (www.sfc.ac.uk) z a greater voice for students in institutional quality systems, supported by a national development service - student participation in quality scotland (sparqs) (www.sparqs.org.uk) z a national programme of Enhancement Themes aimed at developing and sharing good practice to enhance the student learning experience, facilitated by QAA Scotland (www.enhancementthemes.ac.uk). The topics for the Enhancement Themes are identified through consultation with the sector and implemented by steering committees whose members are drawn from the sector and the student body. The steering committees have the task of establishing a programme of development activities, which draw on national and international good practice. Publications emerging from each Theme are intended to provide important reference points for HEIs in the ongoing strategic enhancement of their teaching and learning provision. Full details of each Theme, its steering committee, the range of research and development activities as well as the outcomes are published on the Enhancement Themes website (www.enhancementthemes.ac.uk). To further support the implementation and embedding of a quality enhancement culture within the sector - including taking forward the outcomes of the Enhancement Themes - an overarching committee, the Scottish Higher Education Enhancement Committee (SHEEC), chaired by Professor Kenneth Miller, Vice-Principal, University of Strathclyde, has the important dual role of supporting the overall approach of the Enhancement Themes, including the five-year rolling plan, as well as institutional enhancement strategies and management of quality. SHEEC, working with the individual topic-based Enhancement Themes' steering committees, will continue to provide a powerful vehicle for progressing the enhancement-led approach to quality and standards in Scottish higher education
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