Hyo Jin Choi

Robust Delay Control for Audio Streaming over Wireless Link

The audio delay is becoming an important factor in audio streaming over short-range wireless network. In this study, we propose an efficient two-level delay control method, called frame sequence adaptation and audio sampling frequency compensation, for achieving stable audio delay with a small variation. To prove the effectiveness of our scheme, we implemented and evaluated the scheme on a Bluetooth network. Experimental results show that our scheme can control audio delay robustly and remove phase shift problem in multi-channel stereophonic audio broadcasting as well.

A method for an integrated simulation linked with scheduling policies on a program-driven simulator

The performance of shared memory multiprocessor systems is dependent on the system software parameters such as the processor scheduling policies as well as on the hardware system parameters. Most existing simulators, however, lack the capability of integrated simulation of both hardware and software because they can run only a single benchmark at one time. We propose a new method on a program-driven simulator basis, which enables the concurrent executions of multiple parallel workloads, thus leads to support the modeling of various scheduling policies on shared memory multiprocessor systems. By using the proposed method, a user may measure and analyze the performance of the system under development more approximately to the real run-time environments.

STARRING: slotted ring-based multiprocessor system with a central directory module

The bus-based multiprocessor system is popular. As the computational workload increases, more processors must be attached to the bus. However, the bus has a limit on the number of the processors that can be attached because of electrical problems. Recently, a ring-based multiprocessor system using a point-to-point link was proposed to replace the bus-based multiprocessor system. The authors propose the STARRING, a ring-based multiprocessor system with a central directory module to better the performance. The central directory module is separated into several physical directories to prevent the bottleneck. The directory module reduces the latency of access to the remote memory. They use the program-driven simulator to evaluate the performance. The simulation results show that the STARRING outperforms the bus-based system and the ring-based system using the link-list cache coherence protocol.