A Dynamic Programming formulation is used to obtain an optimal strategy for the handoff problem in cellular radio systems. The formulation includes the modeling of the underlying randomness in received signal strengths and of the mobile’s movements. The cost function is designed such that there is a cost associated with switching and a reward for improving the quality of the call. The optimum d...

We present a framework for designing stable control schemes for systems with changing dynamics – systems whose dynamics change as the state evolves through different regions in the state space. Systems with changing dynamics (SCD) form a subset of hybrid systems; their stabilization is therefore a problem in hybrid control. It is often difficult or even impossible to design a single controller ...

The 4G mobile system is a collection of radio networks providing access to IP based services. It ensures seamless roaming and users are always connected to the best network providing QoS (Quality of Service) to the end user. The mechanism of switching to a different network is termed as vertical handoff. In this paper we propose a vertical handoff management architecture which ensures efficient...

We present TimeTilt, a sensor-based technique that allows multiple windows switching on mobile devices, and which overcomes the limitations of mobile devices, i.e. their impoverished input bandwidth (often no keyboard, a small tactile screen and the drawbacks of one-handed interaction). TimeTilt, which is based on a lenticular metaphor, aims at both reducing the activation time when switching b...

We propose a novel switching control law for the posture stabilization of a wheeled mobile robot, that utilizes the (energetic) passivity of the system's open-loop dynamics with non-negligible inertial effects. The proposed passivity-based switching control law ensures that the robot's (x, y)-position enters into an arbitrarily small (as speci ed by user-designed error-bound) level set of a cer...

Channel allocation schemes in a mobile computing (wireless) environment can be either static or dynamic. Static allocation offers negligible channel acquisition time and zero message complexity and works well at a low system load; the performance steadily decreases as system load increases since many calls are dropped; in case of even temporary hot spots many calls may be dropped by a heavily l...

In previous work, we addressed how the world sometimes mandates switches in human behaviors [2]. This lead to a characterization of how humans manage such mandatory transitions. In addition to mandatory behavior switches, there are also situations where humans exhibit discretionary behavior switches. In this paper, we present a mathematical characterization of discretionary behavior switches wh...

Background: A simple, portable measure of daytime sleepiness is the Oxford Sleep Resistance (OSLER-2) test; however its use is limited to those with good hand function. This study modified the OSLER-2 test to assess the measurement of daytime sleepiness using two alternative, non-hand-held response switches. Methods: The unit was modified to accept the standard hand-held switch, a head-tap swit...