Browsing by Author "Kuo, Tei-Wei"

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An anomaly prevention approach for real-time task scheduling
(2009-01-01)
Chen, Ya-Shu
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Chang, Li-Pin
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Kuo, Tei-Wei
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Mok, Aloysius K.
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資訊工程學系
This research responds to practical requirements in the porting of embedded software over platforms and the well-known multiprocessor anomaly. In particular, we consider the task scheduling problem when the system configuration changes. With mutual-exclusive resource accessing, we show that new violations of the timing constraints of tasks might occur even when a more powerful processor or device is adopted. The concept of scheduler stability and rules are then proposed to prevent scheduling anomaly from occurring in task executions that might be involved with task synchronization or I/O access. Finally, we explore policies for bounding the duration of scheduling anomalies. (c) 2008 Elsevier Inc. All rights reserved.
An efficient B-tree layer implementation for flash-memory storage systems
(2007)
Wu, Chin-Hsien
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Kuo, Tei-Wei
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Chang, Li Ping
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資訊工程學系
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Department of Computer Science
With the significant growth of the markets for consumer electronics and various embedded systems, flash memory is now an economic solution for storage systems design. Because index structures require intensively fine-grained updates/modifications, block-oriented access over flash memory could introduce a significant number of redundant writes. This might not only severely degrade the overall performance, but also damage the reliability of flash memory. In this paper, we propose a very different approach, which can efficiently handle fine-grained updates/modifications caused by B-tree index access over flash memory. The implementation is done directly over the flash translation layer (FTL); hence, no modifications to existing application systems are needed. We demonstrate that when index structures are adopted over flash memory, the proposed methodology can significantly improve the system performance and, at the same time, reduce both the overhead of flash-memory management and the energy dissipation. The average response time of record insertions and deletions was also significantly reduced.
Configurability of performance and overheads in flash management*
(2006)
Kuo, Tei-Wei
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Hsieh, Jen-Wei
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Chang, Li-Pin
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Chang, Yuan-Hao
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資訊工程學系
Flash memory has been widely considered as a good alternative for storage system implementations because it offers superior vibration tolerance and power efficiency, compared to hard-disks. Because of its unique characteristics, direct applications of disk management methods over flash memory might result in performance degradation and even the reducing of the lifetime. The management issues become even more challenging, especially when the capacity of flash memory increases significantly in the past few years. In this paper, we summarize our work on several important issues in flash memory management, where system performance and management overheads are considered. The capability of the proposed methodology was evaluated by a series of experiments to provide more insights in system designs.
Introduction to the Special Issue on Real-Time, Embedded and Cyber-Physical Systems
(2014-11-01)
Chang, Li-Pin
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Kuo, Tei-Wei
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Gill, Chris
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Nakazawa, Jin
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交大名義發表
Multiprocessor Frequency Locking for Real-Time Task Synchronization
(2008-01-01)
Chen, Ya-Shu
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Chang, Li-Pin
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Kuo, Tei-Wei
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資訊工程學系
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Department of Computer Science
Energy-efficient real-time task scheduling is complicated by the deployment of co-processors. The problem complexity comes from the complexity in multiprocessor task scheduling and the difficulty in the trading of priority inversion with energy consumption. In this paper, a multiprocessor task synchronization protocol is proposed by locking the frequency of each (co-)processor and synchronizing resource sharing of tasks in a systematic way and with cross-(co)processor considerations. The well-known Priority Ceiling Protocol is taken as an example for its extension on energy-efficient real-time multiprocessor scheduling. The objective is to minimize the energy consumption of a task set and, at the same time, meet the task deadlines. The capability of the proposed methodology is evaluated by a series of experiments, for which encouraging results are presented.
Special Issue on EUC 2007
(2010-04-01)
Chang, Li-Pin
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Kuo, Tei-Wei
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資訊工程學系
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Department of Computer Science
Time-division-based cyclic scheduling for UMTS high-speed downlink shared-channels
(2007-07-01)
Gan, Chai-Hien
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Perng, Nei-Chiung
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Lin, Phone
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Kuo, Tei-Wei
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資訊工程學系
Third Generation Partnership Project working group proposes the high-speed downlink packet access to speed up downlink transmission for the universal mobile telecommunication system, where the time-division-based high-speed downlink shared-channel (HS-DSCH) approach is adopted. Our previous work proposed the shared-channel assignment and scheduling (SCAS) scheme to efficiently schedule the DSCH to serve different connections, which guarantees the requested transmission rate for each connection. However, limitations exist in the SCAS scheme: 1) the requested transmission rates of connections must be two's power numbers of the basic transmission rate and 2) all served connections should be rescheduled while a new request is. granted, which introduces extra rescheduling overhead to the system. This paper proposes the elastic shared-channel assignment and scheduling (eSCAS) scheme to overcome these limitations. We formally prove the correctness of the eSCAS scheme. An analytical model and simulation experiments are conducted to compare the performance for eSCAS and SCAS. Our study shows that eSCAS can significantly improve the acceptance rate for new connections without increasing the rescheduling overhead.