Taewoong Kim

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In distributed real-time systems, a task activated periodically by the completion of its preceding task can be modeled as a periodic task with activation jitter. An activation jitter of a task is defined as the difference between the worst case and best case response times of its preceding task. Because current approaches assume that the best case response(More)
This paper addresses the problem of scheduling periodic messages in demand priority network standardized by IEEE 802.12 Committee. As regards the real-time property of the demand priority network, unnecessary blocking time due to its round-robin-based MAC protocol may cause periodic messages to miss their hard deadlines and result in low schedulability of(More)
In real-time control system, output jitter of a task is important when feedback control loops are implemented as execution of periodic tasks. Output jitter refers to the variation of response time of a periodic task. For the stability of the control system, output jitter should be reduced. This paper aims to reduce the output jitter of real-time tasks under(More)
In IEEE 802.12 network, a repeater arbitrates among transmission requests on a round robin basis. A node can transmit a packet only when it is granted by the repeater. Recently, the IEEE 802.12 Committee approved a burst mode in which a node can transmit multiple packets per grant. In burst mode a bandwidth, or the number of packets per grant should be(More)
In IEEE 802.12 network, a repeater arbitrates the network access contentions among the nodes on round robin basis. The node having received a grant from the repeater, can transmit a frame. The burst mode, a newly approved feature in IEEE 802.12 network, allows a node to transmit multiple frames per grant. This paper proposes a bandwidth allocation scheme(More)
This paper addresses the problem of delivering real-time messages, both periodic and aperiodic, over bre channel arbitrated loop. Periodic messages typically have hard real-time constraints whereas aperiodic tasks are delivered based on the best-e ort approach. The deadlines of periodic messages are guaranteed by limiting the packet size under the access(More)
The amount of immutable files, such as images, video clips, audio files, and e-mail messages, is expected to grow significantly, as users actively generate, distribute, share, and re-use digital contents. In this paper, we present BeanFS, a distributed file system for a large number of immutable files. A key features of BeanFS include (1) the volume-based(More)
We propose a novel approach to recognize positive or negative emotions from acoustic signals in movies by extracting musical components such as tempo, loudness and melody and then by applying ANFIS Model with fuzzy clustering. In order to extract emotional features in acoustic signals, we first transform the sound into a spectrogram. The spectrogram(More)
In distributed control systems, real-time tasks may be classi ed into local tasks and global tasks. Local tasks are usually bound to a speci c node and responsible for hard real-time functions to control I/O devices whereas global tasks perform soft real-time functions such as data logging, status reporting, and statistical analysis. Such a global task is(More)