7551391
The Role of Time in Engineering Computer Music Systems
Discussion of time in interactive computer music systems engineering has been largely limited to data acquisition rates and latency. Since music is an inherently time-based medium, we believe that time plays a more important role in both the usability and implementation of these systems. In this paper, we present a time design space, which we use to expose some of the challenges of developing computer music systems with time-based interaction. We describe and analyze the time-related issues we encountered whilst designing and building a series of interactive music exhibits that fall into this design space. These issues often occur because of the varying and sometimes conflicting conceptual models of time in the three domains of user, application (music), and engineering. We present some of our latest work in conducting gesture interpretation and frameworks for digital audio, which attempt to analyze and address these conflicts in temporal conceptual models.
368432
Personal orchestra: a real-time audio/video system for interactive conducting
Jan Borchers1, Eric Lee1, Wolfgang Samminger2, Max Mühlhäuser3 1 Media Computing Group, Department of Computer Science, RWTH Aachen University, 52056 Aachen, Germany e-mail: borchers@cs.rwth-aachen.de 2 Telecooperation Department, University of Linz, 4040 Linz, Austria e-mail: wolfgang.samminger@liwest.at; eric@cs.rwth-aachen.de 3 Telecooperation Group, Darmstadt University, 64283 Darmstadt, Germany e-mail: max@informatik.tu-darmstadt.de
7621577
Towards a quantitative analysis of audio scrolling interfaces
We present the results of a user study inspired by previous work in document navigation comparing rate and position control for navigating an audio timeline. Although interfaces for controlling playback speed (rate) are favored over playback position, we found that position control is, on average, 15-19% faster than rate control when searching for targets 90 to 100 seconds away in the audio timeline. Additional studies are being planned to further characterize audio scrolling performance with position and rate controls.
1549095
Education, entertainment and authenticity: lessons learned from designing an interactive exhibit about medieval music
In this paper we describe the design experience gathered from creating an interactive exhibit about medieval music. This system was designed as an educational exhibit that relies on audio as its only feedback channel. We focused our work on three major goals: educational value, entertainment aspects, and historic authenticity. We present insight into the challenges in designing a system with these goals, and how they could be solved.
7453458
Designing time-based interactions with multimedia
The current model of time in multimedia frameworks poses particular problems when designing multimedia systems with time-based interaction. We propose to expand and extend an existing distinction between semantic time and real time from music and film theory to multimedia systems design. The semantic time concept also forms the foundation of a new software framework for multimedia systems that we are building, that, unlike most existing frameworks, includes mechanisms for time-based effects such as time-stretching.
18614557
On Mass-Conserving Least-Squares Methods
Least-squares variational methods have several practical and theoretical advantages for solving elliptic partial differential equations, including symmetric positive definite discrete operators and a sharp error measure. One of the potential drawbacks, especially in three dimensions, is that mass conservation is achieved only in a least-squares sense, and underresolved solutions are especially vulnerable to poor conservation. For the stationary Navier-Stokes equations, which are typically rewritten as a larger system of first-order equations, the loss of mass in the approximate solution is strongly dependent upon the boundary conditions used. A new first-order system reformulation of the Navier-Stokes equations is presented that admits a wider range of mass-conserving boundary conditions. This new formulation is shown to provide both excellent mass conservation and excellent algebraic multigrid performance for three different problems, a square channel, backward-facing step, and branching tubes with two generations of bifurcations.
2880434
The Virtual Waiting Time of the M/G/1 Queue with Impatient Customers
The M/G/1 queue with impatient customers is studied. The complete formula of the limiting distribution of the virtual waiting time is derived explicitly. The expected busy period of the queue is also obtained by using a martingale argument.
207225124
A Linear Programming Approach to Discriminant Analysis with a Reserved-Judgment Region
A linear-programming model is proposed for deriving discriminant rules that allow allocation of entities to a reserved-judgment region. The size of the reserved-judgment region, which can be controlled by varying parameters within the model, dictates the level of aggressiveness (cautiousness) of allocating (misallocating) entities to groups. Results of simulation experiments for various configurations of normal and contaminated normal three-group populations are reported for a variety of parameter selections. Results of cross-validation experiments using real data sets are also reported. Both the simulation and cross-validation experiments include comparison with other discriminant analysis techniques. The results demonstrate that the proposed model is useful for deriving discriminant rules that reduce the chances of misclassification, while maintaining a reasonable level of correct classification.
9981963
Static Scheduling of Synchronous Data Flow Programs for Digital Signal Processing
Large grain data flow (LGDF) programming is natural and convenient for describing digital signal processing (DSP) systems, but its runtime overhead is costly in real time or cost-sensitive applications. In some situations, designers are not willing to squander computing resources for the sake of programmer convenience. This is particularly true when the target machine is a programmable DSP chip. However, the runtime overhead inherent in most LGDF implementations is not required for most signal processing systems because such systems are mostly synchronous (in the DSP sense). Synchronous data flow (SDF) differs from traditional data flow in that the amount of data produced and consumed by a data flow node is specified a priori for each input and output. This is equivalent to specifying the relative sample rates in signal processing system. This means that the scheduling of SDF nodes need not be done at runtime, but can be done at compile time (statically), so the runtime overhead evaporates. The sample rates can all be different, which is not true of most current data-driven digital signal processing programming methodologies. Synchronous data flow is closely related to computation graphs, a special case of Petri nets. This self-contained paper develops the theory necessary to statically schedule SDF programs on single or multiple processors. A class of static (compile time) scheduling algorithms is proven valid, and specific algorithms are given for scheduling SDF systems onto single or multiple processors.
38798257
A hardware-software codesign methodology for DSP applications
The authors describe a systematic, heterogeneous design methodology using the Ptolemy framework for simulation, prototyping, and software synthesis of systems containing a mixture of hardware and software components. They focus on signal-processing systems in which the hardware typically consists of custom data paths, finite-state machines (FSMs), glue logic and programmable processors. The software is one or more embedded programs running on the programmable components.<<ETX>>