Seon-Yeong Park

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This paper presents a novel buffer management scheme for portable media players equipped with flash memory. Though flash memory has various advantages over magnetic disks such as small and lightweight form factor, solid-state reliability, low power consumption, and shock resistance, its physical characteristics imposes several limitations. Most notably, it(More)
In most operating systems which are customized for disk-based storage system, the replacement algorithm concerns only the number of memory hits. However, flash memory has different read and write cost in the aspects of time and energy so the replacement algorithm with flash memory should consider not only the hit count but also the replacement cost caused(More)
Multicore processors deliver a higher throughput at lower power consumption than unicore processors. In the near future, they will thus be widely used in mobile real-time systems. There have been many research on energy-efficient scheduling of real-time tasks using DVS. These approaches must be modified for multicore processors, however, since normally all(More)
The ever-increasing requirement for high-performance and huge-capacity memories of emerging embedded applications has led to the widespread adoption of SDRAM and NAND flash memory as main and secondary memories, respectively. In particular, the use of energy consuming memory, SDRAM, has become burdensome in battery-powered embedded systems. Intuitively,(More)
For the last few years, the major driving force behind the rapid performance improvement of SSDs has been the increment of parallel bus channels between a flash controller and flash memory packages inside the solid-state drives (SSDs). However, there are other internal parallelisms inside SSDs yet to be explored. In order to improve performance further by(More)
Laptop computers and tablet PCs currently exploit swap system with their second storage media as a cost effective solution to extend limited memory space. The rapidly evolving flash memory technology starts to replace the magnetic disks of these computers by flash memory due to its advantageous characteristics such as energy efficiency and mechanical shock(More)
DVS is becoming an essential feature of state-of-the-art mobile processors. Interval-based DVS algorithms are widely employed in general purpose operating systems thanks to their simplicity and transparency. Such algorithms have a few problems, however, such as delayed response, prediction inaccuracies, and underestimation of the performance demand. In this(More)
We propose a joint low-density parity-check (LDPC) code scheme for multi-user relay channel. Joint LDPC codes guarantee high level of performance and achieved service quality. In this paper, we describe how to apply proposed model to relay channel and analyze a method of optimization. Additionally, we show how efficient joint LDPC code scheme using(More)
A very promising approach for using NAND flash memory as a storage medium is a flash file system. In order to design a higher-performance flash file system, two issues should be considered carefully. One issue is the design of an efficient index structure that contains the locations of both files and data in the flash memory. For large-capacity storage, the(More)