596 research outputs found

    Moment balancing templates for (d, k) - constrained codes and run-length limited sequences

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    The first-order moment of (d, k) -constrained codes is investigated in this paper. A generalized moment balancing template is proposed to encode a (d, k) sequence into a single insertion of deletion correcting codeword without losing the constraint property. By relocating 0's in moment balancing runs, which appear in a pairwise manner of a (d, k) sequence, the first-order moment of this sequence can be modified to satisfy the Varshamov-Tenengolts construction. With a reasonably large base in the modulo system introduced by the Varshamov-Tenengolts construction, this generalized moment balancing template can be applied to run-lenght limited sequences. The asymptotic bound of the redundancy introduced by the template for (d, k) sequences is of the same order as the universal template for random sequences and, therefore, the redundancy is small and suitable for long sequences of practical interest.http://ieeexplore.ieee.org/servlet/opac?punumber=18nf201

    Space Shuttle/TDRSS communication and tracking systems analysis

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    In order to evaluate the technical and operational problem areas and provide a recommendation, the enhancements to the Tracking and Data Delay Satellite System (TDRSS) and Shuttle must be evaluated through simulation and analysis. These enhancement techniques must first be characterized, then modeled mathematically, and finally updated into LinCsim (analytical simulation package). The LinCsim package can then be used as an evaluation tool. Three areas of potential enhancements were identified: shuttle payload accommodations, TDRSS SSA and KSA services, and shuttle tracking system and navigation sensors. Recommendations for each area were discussed

    A Derivation of the Tonal Hierarchy from Basic Perceptual Processes

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    In recent decades music psychologists have explained the functioning of tonal music in terms of the tonal hierarchy, a stable schema of relative structural importance that helps us interpret the events in a passage of tonal music. This idea has been most influentially disseminated by Carol Krumhansl in her 1990 monograph Cognitive Foundations of Musical Pitch. Krumhansl hypothesized that this sense of the importance or centrality of certain tones of a key is learned through exposure to tonal music, in particular by learning the relative frequency of appearance of the various pitch classes in tonal passages. The correlation of pitch-class quantity and structural status has been the subject of a number of successful studies, leading to the general acceptance of the pitch-distributional account of tonal hierarchy in the field of music psychology. This study argues that the correlation of pitch-class quantity with structural status is a byproduct of other, more fundamental perceptual properties, all of which are derived from aspects of everyday listening. Individual chapters consider the phenomena of consonance and dissonance, intervallic rootedness, the short-term memory for pitch collection, and the interaction of temporal ordering and voice-leading that Jamshed Bharucha calls melodic anchoring. The study concludes with an elaborate self-experiment that observes the interaction of these properties in a pool of 275 stimuli, each of which is constructed from a single dyad plus one subsequent tone

    Enhancing Usability, Security, and Performance in Mobile Computing

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    We have witnessed the prevalence of smart devices in every aspect of human life. However, the ever-growing smart devices present significant challenges in terms of usability, security, and performance. First, we need to design new interfaces to improve the device usability which has been neglected during the rapid shift from hand-held mobile devices to wearables. Second, we need to protect smart devices with abundant private data against unauthorized users. Last, new applications with compute-intensive tasks demand the integration of emerging mobile backend infrastructure. This dissertation focuses on addressing these challenges. First, we present GlassGesture, a system that improves the usability of Google Glass through a head gesture user interface with gesture recognition and authentication. We accelerate the recognition by employing a novel similarity search scheme, and improve the authentication performance by applying new features of head movements in an ensemble learning method. as a result, GlassGesture achieves 96% gesture recognition accuracy. Furthermore, GlassGesture accepts authorized users in nearly 92% of trials, and rejects attackers in nearly 99% of trials. Next, we investigate the authentication between a smartphone and a paired smartwatch. We design and implement WearLock, a system that utilizes one\u27s smartwatch to unlock one\u27s smartphone via acoustic tones. We build an acoustic modem with sub-channel selection and adaptive modulation, which generates modulated acoustic signals to maximize the unlocking success rate against ambient noise. We leverage the motion similarities of the devices to eliminate unnecessary unlocking. We also offload heavy computation tasks from the smartwatch to the smartphone to shorten response time and save energy. The acoustic modem achieves a low bit error rate (BER) of 8%. Compared to traditional manual personal identification numbers (PINs) entry, WearLock not only automates the unlocking but also speeds it up by at least 18%. Last, we consider low-latency video analytics on mobile devices, leveraging emerging mobile backend infrastructure. We design and implement LAVEA, a system which offloads computation from mobile clients to edge nodes, to accomplish tasks with intensive computation at places closer to users in a timely manner. We formulate an optimization problem for offloading task selection and prioritize offloading requests received at the edge node to minimize the response time. We design and compare various task placement schemes for inter-edge collaboration to further improve the overall response time. Our results show that the client-edge configuration has a speedup ranging from 1.3x to 4x against running solely by the client and 1.2x to 1.7x against the client-cloud configuration

    Recent Advances in Wireless Communications and Networks

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    This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters

    Virtual orchestration: a film composer's creative practice

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    The advent of digital technologies has led to a major change in the process of film music composition; consequent developments in music technology have forced film composers to adapt to this change. Technological innovations such as digital audio workstations (DAWs) and virtual musical instruments have made possible the creation of virtual orchestras that are technologically capable of simulating the sound and behaviour of a traditional acoustic orchestra. This has had an effect on film music production and on the creative process of the professional film composer in a way that today, creating orchestral simulations or 'mock-ups' that imitate live orchestras (or smaller ensembles) has become a requirement in the film industry and thus an essential part of the film-scoring process. In the context of contemporary film music production, this thesis investigates how orchestral simulations are composed and created using computer music technology and virtual sample-based instruments. In asking 'how', the focus is on the film composer's activities and thought processes during this creative cycle, along with the nature of the interactive relationship between composer and music materials. This study aims to show the complexity of the film composer's creative practice and to advance understanding of how the use of computer music technology and orchestral sample libraries is influencing the compositional process and compositional outcome. To address these questions, a qualitative multiple case study methodology approach was chosen that included examination of the practice of seven professional film composers working in the field of feature film as the primary valid source of data. The exploration involved semi-structured interviews with composers, observations and analysis of their studio practice and inspection of their compositional tools. Taken as a whole, the evidence provided by this study is that the process of creating orchestral simulations is a process of film music composition during which professional film composers are creating orchestral sounds through the use of computers, digital sequencing, samplers and sample-based virtual acoustic instruments for the realisation of musical works. It is a process of using and manipulating recorded samples of real acoustic instruments to generate an expressive and convincing musical performance through sample-based orchestral simulation. A characteristic of this compositional practice is that it is a continuous process that proceeds in stages over time where all procedures can be applied repeatedly between stages. The process of creating orchestral simulations for the purpose of the film score is a multifaceted compositional activity involving a complex set of relationships among different compositional states of mind and compositional activities in which film composers experience music and interact with musical materials and media in various ways. This creative activity is a process involving a single person and a mixture of various compositional tools, the composer's skills and abilities brought into existence through a creative process that requires a thorough blend of art and craft to be demonstrated at all times

    GEOBIA 2016 : Solutions and Synergies., 14-16 September 2016, University of Twente Faculty of Geo-Information and Earth Observation (ITC): open access e-book

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    Software for Exascale Computing - SPPEXA 2016-2019

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    This open access book summarizes the research done and results obtained in the second funding phase of the Priority Program 1648 "Software for Exascale Computing" (SPPEXA) of the German Research Foundation (DFG) presented at the SPPEXA Symposium in Dresden during October 21-23, 2019. In that respect, it both represents a continuation of Vol. 113 in Springer’s series Lecture Notes in Computational Science and Engineering, the corresponding report of SPPEXA’s first funding phase, and provides an overview of SPPEXA’s contributions towards exascale computing in today's sumpercomputer technology. The individual chapters address one or more of the research directions (1) computational algorithms, (2) system software, (3) application software, (4) data management and exploration, (5) programming, and (6) software tools. The book has an interdisciplinary appeal: scholars from computational sub-fields in computer science, mathematics, physics, or engineering will find it of particular interest

    CHORUS Deliverable 2.1: State of the Art on Multimedia Search Engines

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    Based on the information provided by European projects and national initiatives related to multimedia search as well as domains experts that participated in the CHORUS Think-thanks and workshops, this document reports on the state of the art related to multimedia content search from, a technical, and socio-economic perspective. The technical perspective includes an up to date view on content based indexing and retrieval technologies, multimedia search in the context of mobile devices and peer-to-peer networks, and an overview of current evaluation and benchmark inititiatives to measure the performance of multimedia search engines. From a socio-economic perspective we inventorize the impact and legal consequences of these technical advances and point out future directions of research
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