• Journal of Mechanical Science and Technology
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• 제15권7호
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• pp.1002-1012
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• 2001

The work reported here is an extensive study of tendon response to multiple cyclic tests including 3% constant peak strain level test (A-type test), 3% constant peak strain level test with two rest periods (B-type test), and 3∼4% different peak strain level test (C-type test). A sufficient number of specimens were tested at each type of the test to statistically evaluate many changes in response during testing and differences in response between each type of the test. In cyclic tests, there were decreses (relaxations) in the peak stresses and hysteresis, increases in the slack strains, and during lower peak strain level (3%) cyclic block after higher peak strain level (4%) cyclic block in the C-type tests. Considering the results of this study and those of the other study of multiple cyclic tests with rest periods by Hubbard and Chun, 1985, recovery phenomena during the rest periods occurred predominantly at the beginning of the rest periods. Consistently in both studies, the effects of rest periods were small and transient compared to the effects of the cyclic extensions. The recovery with cycles at lower peak strain level (3%) after higher peak strain level (4%) in the C-type test has not been previously documented. This recovery seems to be a natural phenomena in tissue behavior so that collagenous structures recover during periods of decreased demand.

• 전력전자학회논문지
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• 제22권4호
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• pp.285-296
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• 2017

This paper proposes an improved modulation scheme for the medium voltage modular multi-level converter (MMC), which operates in the nearest level control and applies in the medium voltage direct current (MVDC) system. In the proposed modulation scheme, the offset (neutral-to-zero output) voltage is adjusted, with the phase voltage magnitude, thereby maintaining a constant value with N+1 level in the controllable modulation index (MI) range. In order to confirm the proposed scheme's validity, computer simulations for the 22.9 kV - 25 MVA MMC were performed with PSCAD/EMTDC, as well as hardware experiments for the 380 V - 10 kVA MMC. The proposed modulation scheme offers to build a constant pole voltage regardless of the MI value, and to build a phase voltage with improved total harmonic distortion (THD).

• 대한기계학회논문집A
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• 제20권4호
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• pp.1241-1250
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• 1996

The characteristics of fatigue cumulative damage and fatigue life of 8-harness satin woven CFRP composites with a circular hole under constant amplitude and 2-level block loading are estimated by Stochastic Makov chain model. It is found in this study that the fatigue damage accumulation behavior is very random and the fatigue damage is accumulated as two regions under constant amplitude fatigue loading. In constant amplitude fatigue loading the predicted mean number of cycles to a specified damage state by Markov chain model shows a good agreement with the test result. The predicted distribution of the fatigue cumulative damage by Markov chain model is similar to the test result. The fatigue life predictions under 2-level block loading by Markov chain model revised are good fitted to the test result more than by 2-parameter Weibull distribution function using percent failure rule.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.195-198
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• 1996

The control objective of drum level of boiler in thermal power plant is to maintain drum level at constant setpoint regardless of disturbance such as main steam flow. The initial response of the drum level loop process is in a direction opposite to the final response. The drum level loop shows inverse response when the power is changed abruptly. We adopt fuzzy controller using knowledge base considering system dynamics for controlling drum level. Finally, the simulation result using the digital simulator for boiler system in Seoul Power Plant Unit 4 shows the validity of fuzzy controller.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.393-404
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• 2016

In this paper, a carrier-based pulse with modulation (PWM) strategy for three-phase three-level inverter is dealt with, which can keep the common mode voltage constant with minimized switching frequency. The voltage gain and the switching frequency in overall operating ranges including overmodulation are investigated and the analytic equations are presented. Finally, the leakage current reduction effect is confirmed by carrying out simulation and experiment. It will be pointed out that the leakage current cannot be perfectly eliminated because of the dead time.

• Journal of Pharmaceutical Investigation
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• 제14권1호
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• pp.11-18
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• 1984

This paper was attempted to study on the effect of metoclopramide or propantheline on the absorption rate and bioavailability and pharmacokinetic parameter of fluorouracil in rats and rabbits. The result are as follows; Metoclopramide increased the absorption rate of fluorouracil but propantheline decreased in situ experiment with rat small intestine. Metoclopramide increased the blood level and relative bioavailability and absorption rate constant of fluorouracil in rabbits. Prolonged the peak blood level (tmax) and decreased the absorption rate constant (Ka) but did not affect the blood level and relative bioavailability of fluorouracil in rabbits. As a matter of fact, it is considerd that the coadministration of metoclopramide or propantheline is more desirable than the single administration of fluorouracil for available dosage regimen.

• ETRI Journal
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• 제16권1호
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• pp.17-34
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• 1994

In this paper, we present an architecture of the constant false alarm rate (CFAR) detector called the generalized order statistics (GOS) CFAR detector, which covers various order statistics (OS) and cell-averaging (CA) CFAR detectors as special cases. For the proposed GOS CFAR detector, we obtain unified formulas for the false alarm and detection probabilities. By properly choosing coefficients of the GOS CFAR detector, one can utilize any combination of ordered samples to estimate the background noise level. Thus, if we use a reference window of size N, we can realize $(2^N-1)$ kinds of CFAR processors and obtain their performances from the unified formulas. Some examples are the CA, the OS, the censored mean level, and the trimmed mean CFAR detectors. As an application of the GOS CFAR detector to multiple target detection, we propose an algorithm called the adaptive mean level detector, which censors adaptively the interfering target returns in a reference window.

• Journal of Pharmaceutical Investigation
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• 제16권1호
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• pp.31-35
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• 1986

Effect of ethanol on the absorption rate, blood level and bioavailability of sulfamethazine (SM) in rats was determined. Absorption rate of SM was determined both by the in vitro and in situ experiment. In vitro, absorption rate of SM in rat small intestine was increased by 0.3, 1.0 and 3.0% ethanol. In situ, absorption rate of SM was increased by 0.3 and 1.0% ethanol but not by 3.0% ethanol. After oral administration, blood level of SM was elevated and relative bioavailability was significantly increased to 114.8% at the dose of 0.6g/kg ethanol but not significantly at the dose of 3.0g/kg ethanol. The time for attainment of peak blood level was changed from 2.5 to 1.5hr. Ethanol enhanced absorption rate constant of SM significantly and reduced elimination rate constant of SM administered orally at the dose of 0.6g/kg ethanol.

• 한국환경보건학회지
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• 제31권4호
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• pp.260-265
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• 2005

Indoor air quality might be affected by source strength of indoor pollutants, ventilation rate, decay rate, outdoor level, and so on. Although technologies measuring these factors exist directly, direct measurements of all factors are not always practical in most field studies. The purpose of this study was to develop an alternative method to estimate the source strength and deposition constant by application of multiple measurements. For the total duration of 60 days, indoor and outdoor $NO_2$ concentrations every 3 days were measured in 30 houses in Seoul, Asan and Daegu. Using a compartment model by mass balance and linear regression analysis, penetration factor (ventilation divided by sum of air exchange rate and deposition constant) and source strength factor (emission rate divided by sum of air exchange rate and deposition constant) were calculated. Subsequently, the source strength and deposition constant were estimated. Natural ventilation was $1.80{\pm}0.42\;ACH,\;1.11{\pm}0.50\;ACH,\;0.92{\pm}0.26\;ACH$ in Seoul, Asan and Daegu, respectively. Calculated deposition constant(K) and source strength of $NO_2,$ in this study were $0.98{\pm}0.28\;hr^{1}\;and\;16.28{\pm}7.47\;ppb/h,$ respectively.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.427-430
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• 2005

A multi-code biorthogonal code keying (MBCK) system consists of multiple waveform coding blocks, and the sum of output codewords is transmitted. Drawback of MBCK is that it requires amplifier with high linearity because its output symbol is multi-level. MBCK with constant amplitude precoding block (CA-MBCK) has been proposed, which guarantees sum of orthogonal codes to have constant amplitude. The precoding block in CA-MBCK is a redundant waveform coder whose input bits are generated by processing the information bits. Redundant bits of constant amplitude coded CA-MBCK are not only used to make constant amplitude signal but also used to improve the BER performance at the receiver. In this paper, we proposed a transmission scheme which combines CA-MBCK with $Q^2PSK$ modulation to improve bandwidth efficiency of CA-MBCK and also uses chip interleaving to maintain a constant amplitude feature of CA-MBCK. bandwidth efficiency of a proposed transmission scheme is increased fourfold. And the BER performance of the scheme is same as that of CA-MBCK.