• Journal of Institute of Control, Robotics and Systems
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• v.5 no.2
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• pp.145-150
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• 1999

A real-time control system, composed of the controlled processor and the controller computer(s), may have a variety of task types, some of which have tight timing-constraints in generating the correct control input. The maximum period of those task failures tolerable by the system is called the hard deadline, which depends on not only fault characteristics but also task characteristics. In the paper, we extend a method deriving the hard deadline in LTI system executing single task. An algorithm to combine the deadlines of all the elementary tasks in the same operation-mode is proposed to derive the hard deadline of the entire system. For the end, we modify the state equation for the task to capture the effects of task failures (delays in producing correct values) and inter-correlation. We also classify the type of executing the tasks according to operation modes associated with relative importance of correlated levels among tasks, into series, parallel, and cascade modes. Some examples are presented to demonstrate the effectiveness of the proposed methods.

• Journal of the Korean Institute of Telematics and Electronics
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• v.7 no.3
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• pp.5-11
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• 1970

Some of the coding method have been discussed by extracting characteristics from vowels and consonants of Korean characters. given letters were sampled through 3$\times$5 mesh and also constituted first matrix system which taken subpatterns of vertical Conponent as variables and then, characteristics of the letters are extracted from the second matrix system expresses by common characteristics which are combined-with first one. Single coding was obtained by scanning the characteristic pattern. a good agree between theoretical values and their measurements and the reproducing of all vowels and consonants of Korean chasacters about coding were certified on the display designed.

• Korean Journal of Agricultural Science
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• v.21 no.2
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• pp.92-102
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• 1994

This study examined Public Evaluation for functions of urban open space environment using a marketing strategy called Importance-Performance analysis. 12 main function attributes for urban open space environment were selected 150 respondents were sampled in Taejon city by personal interview. Ratings used mean values from a seven-point scale. Results were then graphically displayed on an easily interpreted two-dimensional 'Action Grid'. Generally Importance Ratings were high, but Performance Ratings were low relatively for various open space environment functions. In air pollution control function the difference was the most large. The results of rating scale analysis indicated repondents' sexual and residence period difference.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.259-261
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• 2008

GIS-based spatial data integration tasks have used exhaustive thematic maps generated from sparsely sampled data or satellite-based exhaustive data. Due to a simplification of reality and error in mapping procedures, such spatial data are usually imperfect and of different accuracy. The objective of this study is to carry out a sensitivity analysis in connection with input topographic data for landslide hazard mapping. Two different types of elevation estimates, elevation spot heights and a DEM from ASTER stereo images are considered. The geostatistical framework of kriging is applied for generating more reliable elevation estimates from both sparse elevation spot heights and exhaustive ASTER-based elevation values. The effects of different accuracy arising from different terrain-related maps on the prediction performance of landslide hazard are illustrated from a case study of Boeun, Korea.

• Journal of Industrial Technology
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• v.34
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• pp.45-52
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• 2014

In this paper the settlement characteristic of shallow foundation on sandy soil overlained by rigid ground was investigated by analyzing results of model tests. For model experiments, model tests were performed with sandy soils sampled from the field, changing the relative density of sandy soil and the ratio of thickness of sandy layer(H) to the width of model strip footing(B). As result of tests, settlement of sandy soils increases as the value of H/B increases, whereas it increases with relative density of soil. Bearing capacity decreases as the thickness of the sand layer relative to the footing width increases. In order to analyze the settlement characteristics of sandy ground, the results of model tests were compared with the predicted values using the empirical formulas proposed by Terzaghi, De Beer and Schmertmann. The method by De Beer was found to be in good agreements with test results.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.221-222
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• 2015

디지털 변전소를 위해 IEC61850 국제 표준 프로토콜을 적용한 보호계전기(IED), 게이트웨이, HMI등이 필드에서 사용되고 있고, 전체 디지털 변전소를 위한 병합장치(Merging Unit: MU)등도 실제 운영되고 있다. 디지털 변전소는 기존 변전소를 효과적으로 운영하기 위해 필요한 높은 수준의 가용성과 전송능력이 필요하다. IEC TC 57 WG10은 디지털 변전소를 위한 이중화 사양으로 IEC SG65C WG15의 IEC62439-3/4 고속 절체 네트워크 운영 프로토콜(Highly Available Seamless Redundancy: HSR),(Parallel Redundancy Protocol: PRP)들을 추천하고 있다. 본 논문에서는 프로세스 버스의 병합장치(MU)로부터 계측된 전류와 전압을 고속 이더넷을 통해 샘플 계측값(Sampled Measured Values: SMV)을 전송받고, 고정밀 IEEE1588v2 PTP(Precision Time Protocol) 시각동기를 하며, 스테이션 레벨에서 MMS와 GOOSE 통신을 하는 계전기와 성능에 대한 것이다.

• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.610-618
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• 2015

This study was conducted to find out the influence of sample size (accumulated survey areas) on the seven biological indices of benthic macroinvertebrates. BMI, the index similar to Zeilika-Marvan’s saprobic index, tended to be independent on the variations of sample size. The other indices (Shannon-Weaver’s diversity, Margalef’s richness, Menhinick’s richness, Pielou’s evenness, and Lenat’s EPT index) showed the considerable variations along with the increase of sample size and environmental conditions. To get the appropriate index values, it should be sampled at least 6 replicates more based on 30×30cm Surber sampler. In addition, the habitat heterogeneity index of benthic macroinvertebrates suggested in this study, it will be able to be used for evaluating the heterogeneity of habitats.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.73-79
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• 2002

The NO emissions at the exhaust manifo1d were investigated with a fast NO analyzer to investigate the cycle-by-cycle variations on NO emissions level and the dependence of NO emissions on combustion. The measurement was performed with a part load condition with respect to the mixture ratios and the changes in loads at 1800rpm. The averaged values were obtained during 200 cycles. We found that there is characteristic pattern in 70 emissions from exhaust port and it was possible to set a representative value with the data sampled during specific period. As the load increased, the characteristics of NO emissions were more dependent on combustion pressures. It was also analyzed that the correlation between combustion pressures and NO emissions for different equivalence ratios tends to increase as the mixture goes leaner, Furthermore, this correlation for the lean mixture near the lean limit seemed to be kept.

• Speech Sciences
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• v.2
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• pp.89-94
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• 1997

This study was attempted to analyze the acoustic characteristics of profoundly deaf students. The 59 profoundly hearing-impaired and 36 normal subjects were divided into 3 age groups: 6-10 yrs group, 11-15 yrs group, and 16-20 yrs group. The voice was sampled in /a/ prolongation, counting, reading, and conversation using the Computerized Speech ,Lab (CSL). The vocal pitch of the deaf subjects was significantly higher than the normal subjects. The younger in age was tended to be higher in pitch and jitter values of the deaf subjects. The three age groups of the deaf subjects did not show any difference in loudness and shimmer, excepted to minimum loudness. The pitch mean of males was significantly lower than that for females.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.9
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• pp.361-367
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• 1985

A new injection method is proposed for active power filters to eliminate AC harmonics in ac input current of nonlinear loads such as rectifiers. By injecting the PWM current determined by the proposed injection method, all the harmonics up to order nn can be eliminated to exactly zero. This PWM injection current can be generated by sampling total harmonic wave at the rate of M and the sampled values are converted into the proposed PWM wave with N pulse-width variables and adjustable current magnitude Im. These variables are deetermined by solving a set of N nonlinear harmonic equations and the harmonic-elimination characteristics of the new injection are investigated through digital computer sinmulation. Also by comparing between the simulated results and the ones synthesized by data stored in EPROM, the possibility of the suggested injection method can be shown.