• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.31-43
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• 2015

For battery based real-time embedded systems, high performance to meet their real-time constraints and energy efficiency to extend battery life are both essential. Real-Time Dynamic Voltage Scaling (RT-DVS) has been a key technique to satisfy both requirements. In this paper, we present an efficient RT-DVS algorithm called EccEDF that is designed based on ccEDF. The proposed algorithm can precisely calculate the maximum unused utilization with consideration of the elapsed time while keeping the structural simplicity of ccEDF, which overlooked the time needed to run the task in calculating the available slack. The maximum unused utilization can be calculated by dividing remaining execution time($C_i-cc_i$) by remaining time($P_i-E_i$) on completion of the task and it is proved using Fluid scheduling model. We also show that the algorithm outperforms ccEDF in practical applications which is modelled using a PXA250 and a 0.28V-to-1.2V wide-operating-range IA-32 processor model.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.9
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• pp.520-529
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• 2002

This paper presents an approach for scheduling network messages with real-time dynamic algorithms. We present the method that calculates an intermediate relative deadline of the message based on the EDF(Earliest Deadline First) scheduling policy. We adjust the slack of message by using this intermediate relative deadline to allocate a priority of message. The priority of the message can be determined accurately by using the slack that calculates in our approach, which increases the schedulability efficiency of the message. As a result, we reduce the worst-case response time and improve the guarantee ratio of real-time messages. Also, we describe the analysis method to check the schedulability on message sets, and show the efficiency of our approach by comparing the results of the DM(Deadline Monotonic) approach and the existing EDF approach with that of the improved EDF in our approach through the simulation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.1
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• pp.218-227
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• 2001

The purpose of this study was to estimate that the relations of weathering speed and shear strength of granite soil by tracing the weathering depth of granite soil from the very moment of its cutting. The results obtained this follows : This paper is about seismic performance of the EDF(Electricite De France) system, that is among various base isolator. A rational modeling of EDF system has been presented that used Nllink element. We get theoretical solutions of equation of motion of the system and compared with numerical solutions using a finite element program. The unification modeling is made by comparing with behavior using Newmark-${\beta}$ method when input earthquake acceleration data. Thus, a verified modeling will apply bridge structures or multi-degree of-freedom systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.3
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• pp.48-57
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• 2005

This paper presents a novel algorithm in order to extract lane-related information based on machine vision techniques. The algorithm makes up for the weak points of the former method, the Edge Distribution Function(EDF)-based approach, by introducing a Lane Boundary Pixel Extractor (LBPE) and the well-known Hough Transform(HT). The LBPE that serves as a filter to extract pixels expected to be on lane boundaries enhances the robustness of machine vision, and provides its results to the HT implementation and EDF construction. The HT forms the accumulator arrays and extracts the lane-related parameters composed of orientation and distance. Furthermore, as the histogram of edge magnitude with respect to edge orientation angle, the EDF has peaks at the orientations corresponding to lane slopes on the perspective image domain. Therefore, by fusing the results from the EDF and the HT the proposed algorithm improves the confidence of the extracted lane-related information. The system shows successful results under various degrees of illumination.

• Journal of Korean Society for Quality Management
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• v.31 no.1
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• pp.109-122
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• 2003

This paper presents a robust process capability index(PCI) based on the expected loss derived from the empirical distribution function(EDF). We propose the EDF expected loss in order to develop a PCI that does not depends on the underlying process distribution. The EDF expected loss depends only on the sample data, so the PCI based on it is robust and it does nor require complex calculations. The inverted normal loss function(INLF) is employed in order to overcome the drawback of the quadratic loss which may Increase unboundedly outside the specification limits. A comprehensive simulation study was performed under various process distributions, in order to compare the accuracy and the precision of the proposed PCI with those of the PCI based on the expected loss derived from the normal distribution. The proposed PCI turned out to be more accurate than the normal PCI in most cases, especially when the process distribution has high kurtosis or skewness. It is expected that the proposed PCI can be utilized In real processes where the true distribution family may not be known.

• Journal of Korean Society for Quality Management
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• v.31 no.4
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• pp.164-175
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• 2003

This paper investigates bootstrap confidence intervals of the process capability index(PCI) based on the expected loss derived from the empirical distribution function(EDF). The PCI based on the expected loss is too complex to derive its confidence interval analytically, so the bootstrap method is a good alternative. We propose three types of the bootstrap confidence interval; the standard bootstrap(SB), the percentile bootstrap(PB), and the acceleration biased­corrected percentile bootstrap(ABC). We also perform a comprehensive simulation study under various process distributions, in order to compare the accuracy of the coverage probability of the bootstrap confidence intervals. In most cases, the coverage probabilities of the bootstrap confidence intervals from the EDF PCI turned out to be more accurate than those from the PCI based on the normal distribution. It is expected that the bootstrap confidence intervals from the EDF PCI can be utilized in real processes where the true distribution family may not be known.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.76-79
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• 2012

Satellite power system is critical for mission design and survival operation. Accordingly power conversion circuit has to stable design and verify for operation condition change (load, voltage, thermal condition). however, multi-stage make complicate for modeling and get all state solution. In this paper present all state solution for multi-stage converter by using Extended Describing Function(EDF) modelling. EDF modelling has merit to solve complex circuit but it has limit too. Because of fundamental approximation, EDF modeling is not match all topology. Consequently, we verify passible topology for EDF modeling and stable design multi-stage converter.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.460-465
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• 2003

Characteristics of 0.98 $\mu$m-pumped erbium-doped fiber (EDF) sources with double-pass forward (DPF) configuration are analyzed by numerical calculation. Various source characteristics such as output power, spectral width and mean-wavelength stability are investigated with the variation of EDF length, pump power and pump wavelength. Some of the numerical results are compared with experimental ones for verification. The results show that the characteristics of sources with DPF configuration can change considerably with the EDF length. It is also found that an optimum design can exist for stable mean-wavelength against fluctuations of pump power and pump wavelength.

• Nuclear industry
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• v.24 no.6 s.256
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• pp.68-72
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• 2004

• The KIPS Transactions:PartA
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• v.16A no.6
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• pp.437-442
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• 2009

For multiprocessor systems, Earliest Deadline First (EDF) based on deadline and Least Laxity First (LLF) based on laxity are not suitable for practical environment since EDF has low schedulability and LLF has high context switching overhead. As a combining of EDF and LLF to improve the performance, Earliest Deadline Zero Laxity (EDZL) was proposed. EDZL is basically the same as EDF. But if the laxity of a task becomes zero, its priority is promoted to the highest level. In this paper, we propose Least Laxity Zero Laxity (LLZL) which is based on LLF. But context switching is allowed only if the laxity of a task on rady queue becomes zero. Simulation results show that LLZL has high schedulability approaching to LLF and low context switching overhead similar to EDF. In comparison with EDZL, LLZL has better performance in both of schedulability and context switching overhead.