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.
5409418
You're The Conductor: A Realistic Interactive Conducting System for Children
This paper describes the first system designed to allow children to conduct an audio and video recording of an orchestra. No prior music experience is required to control the orchestra, and the system uses an advanced algorithm to time stretch the audio in real-time at high quality and without altering the pitch. We will discuss the requirements and challenges of designing an interface to target our particular user group (children), followed by some system implementation details. An overview of the algorithm used for audio time stretching will also be presented. We are currently using this technology to study and compare professional and non-professional conducting behavior, and its implications when designing new interfaces for multimedia. You're the Conductor is currently a successful exhibit at the Children's Museum in Boston, USA.
14010108
conga: A Framework for Adaptive Conducting Gesture Analysis
Designing a conducting gesture analysis system for public spaces poses unique challenges. We present conga, a software framework that enables automatic recognition and interpretation of conducting gestures. conga is able to recognize multiple types of gestures with varying levels of difficulty for the user to perform, from a standard four-beat pattern, to simplified up-down conducting movements, to no pattern at all. conga provides an extendable library of feature detectors linked together into a directed acyclic graph; these graphs represent the various conducting patterns as gesture profiles. At run-time, conga searches for the best profile to match a user's gestures in real-time, and uses a beat prediction algorithm to provide results at the sub-beat level, in addition to output values such as tempo, gesture size, and the gesture's geometric center. Unlike some previous approaches, conga does not need to be trained with sample data before use. Our preliminary user tests show that conga has a beat recognition rate of over 90%. conga is deployed as the gesture recognition system for Maestro!, an interactive conducting exhibit that opened in the Betty Brinn Children's Museum in Milwaukee, USA in March 2006.
2078708
Improving orchestral conducting systems in public spaces: examining the temporal characteristics and conceptual models of conducting gestures
Designing interactive conducting exhibits for public spaces poses unique challenges, primarily because the conceptual model of conducting music varies amongst users. In a user study, we compared how conductors and non-conductors place their beats when conducting to a fixed orchestral recording of Radetzky March, and found significant differences between these two groups. Conductors lead the actual music beat with their gestures by an average of 150 ms, compared to 50 ms for non-conductors; non-conductors also vary their placement of the beat 50% more than conductors. Furthermore, we found differences in how users conceptually mapped their gestures to the music, such as conducting to the musical rhythm rather than to the beat. We are incorporating these results into an upcoming conducting system for public spaces to increase its usability; we believe they also apply to a more general class of musical gestures such as dance.
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.
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.
10518317
Embedded Software
Syntax It is useful to separate syntactic issues from semantic issues. An abstract syntax defines how a design can be decomposed into interconnected components, without being concerned with how a design is represented on paper or in a computer file (that is the concern of the concrete syntax). An abstract syntax is also not concerned with the meaning of the interconnections of components, nor even what a component is. A design is a set of components and relationships among them, where the relationships conform to this abstract syntax. Here, we describe the abstract syntax using informal diagrams that illustrate these sets and relations by giving use cases, although formalizing the abstract syntax is necessary for precision. Port Port Actor Actor
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>>
13888487
Hierarchical finite state machines with multiple concurrency models
This paper studies the semantics of hierarchical finite state machines (FSM's) that are composed using various concurrency models, particularly dataflow, discrete-events, and synchronous/reactive modeling. It is argued that all three combinations are useful, and that the concurrency model can be selected independently of the decision to use hierarchical FSM's. In contrast, most formalisms that combine FSM's with concurrency models, such as statecharts (and its variants) and hybrid systems, tightly integrate the FSM semantics with the concurrency semantics. An implementation that supports three combinations is described.
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.