• PNF and Movement
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• v.17 no.1
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• pp.1-9
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• 2019

Purpose: This study investigates the effects of task-oriented training for a left trunk flexion pattern using real-time ultrasound imaging in a stroke patient with unilateral neglect symptoms. Methods: This study used the ABA experimental design, which is a single-subject research method among individual case research methods. For the ABA experimental design, changes in the degree of unilateral neglect, balance ability, and the thickness of the lateral abdominal muscle were visually analyzed during the baseline process, in the intervention period, and after the intervention. The experiments were performed 24 times in total for 8 times in each of the 3 periods. The unilateral neglect was measured using the Albert test, balance ability was measured using the Berg balance test, and the thickness of the lateral abdominal muscle was measured using ultrasound imaging. The subject was a 50-year-old male patient with unilateral neglect caused by right cerebral hemorrhage. He performed task-oriented training for a voluntary left trunk flexion pattern using real-time ultrasound imaging during the intervention period. Results: The result of comparing the data collected during the intervention period with the data point average of the baseline process showed that balance ability improved and the tendency line was above the baseline. The tendency line of unilateral neglect was below the baseline and showed a decreasing tendency. The thickness of the lateral abdominal muscle showed an increasing trend and the tendency line was above the baseline. Conclusion: The results of this study suggest that the task-oriented training for left trunk flexion pattern using real-time ultrasound imaging has a beneficial effect on balance ability, the degree of unilateral neglect, and the strength of the lateral abdominal muscle in unilateral neglect patients.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.5
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• pp.506-517
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• 2000

In distributed real-time system, a task activated 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 asthe difference between the worst case and the best case response time of its preceding task. Becausethe existing approaches assume that the best case response time is much smaller than the actual one,the activation jitter and the worst case response time of lower priority tasks are overestimated. Thispaper proposes a new analysis technique to calculate the best case response time more precisely andto reduce the activation jitter bounds. The proposed technique obtains the best case response time byconsidering the relative phase between tasks. The precise analysis of the activation jitters can reducethe worst case response time of other tasks and increase the schedulability. The simulation resultsshow that the proposed analysis technique improves the accuracy of the best case and the worst caseresponse time up to 40% and 6%, respectively.

• KIISE Transactions on Computing Practices
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• v.23 no.6
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• pp.392-396
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• 2017

Although mobile device-related technologies have developed rapidly, many problems arising from resource constraints have not been solved. Computation offloading that uses resources of cloud servers over the Internet was proposed to overcome physical limitations, and many studies have been conducted in terms of energy saving. However, completing tasks within their deadlines is more important than saving energy in real-time applications. In this paper, we proposed an offloading decision scheme considering the scheduling latency in the cloud to support real-time applications. The proposed scheme can improve the reliability of real-time tasks by comparing the estimated laxity of offloading a task with the estimated laxity of executing a task in a mobile device and selecting a more effective way to satisfy the task's deadline.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.3_4
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• pp.170-186
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• 2004

Recently, for real-time applications such as multimedia and signal processing, it becomes increasingly important to provide a probabilistic guarantee that each task in the application meets its deadline with a given probability. To provide the probabilistic guarantee, an analysis method is needed that can accurately predict the deadline miss probability for each task in a given system. This paper proposes a stochastic analysis method for real-time systems that use priority-driven scheduling, such as Rate Monotonic and Earliest Deadline First, in order to accurately compute the deadline miss probability of each task in the system. The proposed method accurately computes the response time distributions for tasks with arbitrary execution time distributions, and thus makes it possible to determine the deadline miss probability of individual tasks. In the paper. through experiments, we show that the proposed method is highly accurate and outperforms exisiting methods proposed in the literature.

• Journal of Electrical Engineering and information Science
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• v.3 no.3
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• pp.396-401
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• 1998

An optimal algorithm is presented for feasibility test and scheduling of real-time tasks where tasks are preemptable and created dynamically. Each task has an arbitrary creation time, ready time, maximum execution time, and deadline. Feasibility test and scheduling are conducted via the same algorithm. Time complexity of the algorithm is O(n) for each newly created task where n is the number of tasks. This result improves the previous result of O(n log n). It is shown that the algorithm can be used for scheduling tasks with different levels of importance. Time complexity of the algorithm for the problem is O(n\ulcorner) which improves the previous results of O(n\ulcorner log n).

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.7-8
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• 2019

In this paper, we applied the migration technique to real-time tasks that have relatively low criticality but still important to be dropped by the mixed-criticality scheduling algorithms. The proposed drop and migrate algorithm analyzes the schedulability by calculating CPU utilization and response time of using task migration. We provide analysis to guarantee the deadline of LO-tasks, by transforming the response time equation specified with migration time. The transformed response time equation was able to analyze the migration schedulability. This algorithm can be used with various mixed-criticality schedulers as a supplementary method. We expect this algorithm will be used for scheduling LO-tasks such as communication task that requires safety guarantee especially in platooning and autonomous driving by utilizing the advantages of multiple node connectivities.

• The Journal of the Korea Contents Association
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• v.10 no.1
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• pp.94-102
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• 2010

In recent years, embedded systems such as cellular phones, Portable Multimedia Player, intelligent appliance, automobile engine control are reshaping the way people live, work, and play. Thereby, services application to guarantee various requirements of users become increasingly sophisticated and complicated, such embedded computing platforms use real-time operating systems (RTOSs) with time determinism. These RTOSs must not only provide predictable services but must also be efficient and small in size. Kernel services should also be deterministic by specifying how long each service call will take to execute. Having this information allows the application designers to better plan their real-time application software so as not to miss the deadline of each task. In this paper, we present the complete generalized real-time scheduling algorithm using multi-dimensional methodology to determine the highest priority in the ready list with 2r levels of priorities in a constant time without additional memory overhead.

• Journal of IKEEE
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• v.5 no.2 s.9
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• pp.164-173
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• 2001

In this paper, we have designed and implemented a new hard embedded real-time system to satisfy hard real-time constraints in moving independently. Real-time kernel should be small size, fast and predictable. Because of the great variety of demands on real time scheduling, a real time kernel should also include a flexible and re-programmable task scheduling discipline. In this paper, we present that real-time applications should be split into small and simple parts with hard real-time constraints. To satisfy these properties, we designed real-time kernel and general kernel, that have their different properties. In real-time tasks, interrupt processing should be run. In general kernel, non real time tasks or general tasks are run. The efficiency of the proposed hard embedded real-time system is shown by comparison results for performance of the proposal real time kernel with both RT-Linux and QNX.

• The Transactions of the Korea Information Processing Society
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• v.4 no.11
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• pp.2891-2902
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• 1997

This paper presents an analysis on the optimal partitioning configuration of cache (memory) for meeting deadlines of periodic and aperiodic real-time task set. Our goal is not only to decrease the deadline missing ratio of each task by minimizing the task utilization, but also to allocate another tasks to idle spaces of cache. For this reason, we suggest an algorithm so that tasks could be allocated to cache segments. Here, the set of cache segments allocated tasks is called a cache partitioning configuration. Based on how tasks allocate to cache segments, we can get various cache partitioning configurations. From these configurations, we obtain the boundary of task utilization that tasks are possible to schedule, and analyze the cache optimal partitioning configuration that can be executed to minimize the task utilization.

• IEMEK Journal of Embedded Systems and Applications
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• v.3 no.1
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• pp.25-29
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• 2008

In this paper, we provide an adaptive power-aware checkpointing scheme for fixed priority-based DVS scheduling in dependable real-time systems. In the provided scheme, we analyze the minimum number of tolerable faults of a task and the optimal checkpointing interval in order to meet the deadline and guarantee its specified reliability. The energy-efficient voltage level at a fault arrival is also analyzed and used in the recovery of the faulty task.