15601356
An optimal proportion of perfect repair
At each failure of a system, with probability p it is perfectly repaired, and with probability 1-p it is restored to its condition just prior to failure. It is shown that there exists a unique p minimizing the long-run repair cost, provided the failure time distribution of the system has strictly DMRL.
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.
36370882
Multi-agent Based Hybrid System for Dynamic Web-Content Adaptation
Context-aware adaptation service is rapidly becoming an important issue. This service overcomes the limitations of wireless devices and maintains adequate service levels in changing environments. The majority of existing studies concentrate on adaptation modules on the client, proxy, or server. These existing studies thus suffer from the problem of having the workload concentrated on a single system. This means that increasing the number of users increases the response time of a user’s request. In this paper, the adaptation module is dispersed and arranged over the client, proxy, and server. The module monitors the context of each system and creates a dispersed adaptation system, optimized for efficient operation. Through this method, faster adaptation work is made possible, even when the number of users increases, and the dividing workload makes more stable system operation possible. In order to evaluate the proposed system, a prototype is constructed and dispersed operations are tested using multimedia content, simulating server overload and comparing the response times and system stability with existing server based adaptation systems. The effectiveness of the system is confirmed through the results.
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.
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.
1540671
Bangarama: Creating Music with Headbanging
Bangarama is a music controller using headbanging as the primary interaction metaphor. It consists of a head-mounted tilt sensor and a guitar-shaped controller that does not require complex finger positions. We discuss the specific challenges of designing and building this controller to create a simple, yet responsive and playable instrument, and show how ordinary materials such as plywood, tin foil, and copper wire can be turned into a device that enables a fun, collaborative music-making experience.
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.