• Title/Summary/Keyword: Control-Response Ratio

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Vibration Control of RC Residential Building Structure Using Sky-Bridge (스카이브릿지를 이용한 RC 주거용 건물의 진동제어)

  • Ahn, Sang-Kyung;Oh, Jung-Keun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.450-453
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    • 2006
  • Coupling adjacent building with supplemental damping devices is a developing method of reduced structural response due to wind and seismic excitations. The philosophy is to allow structures, vibrating at different frequencies, to exert control forces upon one another to reduce the overall responses of the system. This paper studies the effect of installing vibration control devices of two high rise building structures(49 stories and 42 stories) connected by sky-bridge. According to the analysis results the use of sky-bridge can be effective in increasing damping ratio of the system.

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Effect of Piezoactuator Length Variation for Vibration Control of Beams (보의 진동제어를 위한 압전 액추에이터의 길이변화 효과 연구)

  • Lee, Young-Sup
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.442-448
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    • 2008
  • This paper presents an approach to define an optimal piezoactuator length to actively control structural vibration. The optimal ratio of the piezoactuator length against beam length when a pair of piezoceramic actuator and accelerometer is used to suppress unwanted vibration with direct velocity feedback (DVFB) control strategy is not clearly defined so far. It is well known that direct velocity feedback (DVFB) control can be very useful when a pair of sensor and actuator is collocated on structures with a high gain and excellent stability. It is considered that three different collocated pairs of piezoelectric actuators (20, 50 and 100 mm) and accelerometers installed on three identical clamped-clamped beams (300 * 20 * 1 mm). The response of each sensor-actuator pair requires strictly positive real (SPR) property to apply a high feedback gain. However the length of the piezoactuator affects SPR property of the sensor-actuator response. Intensive simulation and experiment shows the effect of the actuator length variation is strongly related with the frequency range of SPR property. A shorter actuator gave a wider SPR frequency range as a longer one had a narrower range. The shorter actuator showed limited control performance in spite of a higher gain was applied because the actuation force was relatively small. Thus an optimal length ratio (actuator length/beam length) was suggested to obtain relevant performance with good stability with DVFB strategy. The result of this investigation could give important information in the design of active control system to suppress unwanted vibration of smart structures with piezoelectric actuators and accelerometers.

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Seismic Response Control Performance of Linear and Nonlinear TLD Models (선형 및 비선형 TLD의 지진응답 제어성능 평가)

  • Lee, Sang-Hyun;Woo, Sung-Sik;Chung, Lan
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2006.03a
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    • pp.519-526
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    • 2006
  • This paper compares the seismic response control performance of linear and non-linear models fer tuned liquid damper (TLD). The existing linear and nonlinear TLD models were used for the numerical analysis of single degree of freedom (SDOF) and multi degree of freedom (MDOF) systems with TLD. The nonlinear model considers the variation of the frequency and damping of the TLD with varying excitation amplitude while the linear one has the invariant parameters. Numerical analysis results from SDOF systems indicate that the nonlinear model shows about 5% better control performance than linear one when the mass ratio is 2% and the optimal parameters for reducing peak responses are dependent on the characteristics of the excitation earthquake loads.

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MANDIBULAR DISTRACTION OSTEOGENESIS WITH COMPRESSION FORCE - BONE DENSITY, HISTOLOGICAL FINDINGS AND TMJ RESPONSE (압축력을 병용한 하악골 신장술)

  • Hwang, Young-Seob;Heo, June;Kim, Uk-Kyu;Park, Seong-Jin;Hwang, Dae-Seok;Kim, Yong-Deok;Chung, In-Kyo;Kim, Kyu-Cheon
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.28 no.6
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    • pp.531-548
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    • 2006
  • The purpose of this study was to investigate the biomechanical, histologic findings of distracted regenerate and TMJ response in modified distraction osteogenesis (DO) technique combined with compression force as biomechanical stimulation method which has been suggested in 2002, and developed thereafter by authors. This study was performed with two experiments. First experiment was designed to explore the optimal ratio of compression force versus distraction force for the new DO technique. Second experiment was planned to evaluate the reaction of TMJ tissue, especially condyle, disc after application of the DO technique with compression force. Total 52 New Zealand adult male-rabbits with 3.0kg body weight were used for the study. For the first study, 30 adult male-rabbits underwent osteotomy at one side of mandibular body and a external distraction device was applied on each rabbit with same manner. In the control group of 10 rabbits, final 8 mm of distraction with 1 mm rate per day was done with conventional DO technique after 5 latency days. For the experimental group of 20 rabbits, a compression force with 1 mm rate per day was added to the distracted mandible on 3-latency day after over-distraction (over-lengthening). As the amount of the rate of compression versus distraction, experimental subgroup I (10 rabbits) was set up as 2 mm compression versus 10 mm distraction (1/5) and experimental subgroup II (10 rabbits) was set up as 3 mm compression versus 11 mm distraction (about 1/3). All 30 rabbits were set up to obtain final 8 mm distraction and sacrificed on postoperative 55 day to analysis on biomechanical, and histologic findings of the bone regenerates. For second study, 22 adult male-rabbits were used to evaluate TMJ response after the DO method application with compression force. In the control group, 10 rabbits was used to be performed with conventional DO method, on the other hand, in a experimental group of 10 rabbits, 10 mm distraction with 2 mm compression (1/5 ratio) was done. The remaining 2 rabbits served as the normal control group. Histomorphologic examinations on both condyle, histological studies on condyle, disc were done at 1, 2, 3, 4, 7 weeks after distraction force application. The results were as follows: 1. On the bone density findings, the experimental group II (force ratio - 1/3) showed higher bone density than the other experimental group (force ratio - 1/5) and control group (control group - $0,2906\;g/cm^2$, experimental group I - $0.2961\;g/cm^2$, experimental group II - $0.3328\;g/cm^2$). 2. In the histologic findings, more rapid bone maturation like as wide lamellar bone site, more trabeculae formation was observed in two experimental groups compared to the conventional DO control group. 3. In morphologic findings of condyle, there were no differences of size and architecture in the condyle in the control and experimental groups. 4. In histologic findings of condyles, there were thicker fiberous and proliferative layers in experimental group than those of control group until 2 weeks after distraction with compression force. But, no differences were seen between two groups on 3, 4, 7 weeks after compression. 5. In histologic findings of disc, more collagen contents in extracellular matrix, more regular fiber bundles, and less elastin fibers were seen in experimental group than control group until 2 weeks after distraction with compression. But, no differences were seen between two groups on 3, 4, 7 weeks after distraction with compression. From this study, we could identify that the new distraction osteogenesis technique with compression stimulation might improve the quality of bone regeneration. The no remarkable differences on TMJ response between control and experimental groups were seen and TMJ tissues were recovered similarly to normal TMJ condition after 3 weeks.

Effects of Partial Cervus elaphus Linne' Extract on Antitumoral Immune Response in Melanoma-induced Mice (부위별(部位別) 녹용(鹿茸)이 흑색종(黑色腫) 유발(誘發) 생쥐의 종양억제(腫瘍抑制)와 면역기능(免疫機能)에 미치는 영향(影響))

  • Oh Ha-Souk;Kim Jang-Hyun
    • The Journal of Pediatrics of Korean Medicine
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    • v.14 no.1
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    • pp.39-78
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    • 2000
  • Introduction: In order to investigate the effects of partial Cervus elaphus Linne' extract on antitumoral immunological, a group of mice are melanoma-induced and observed reponses in terms of the number of lymphocyte, CD4+ count, CD8+ count, CD4+/CD8+ ratio in blood and spleen, change in body weight, melanoma weight, spleen index, NK cell activity and productivity of IL-2 in each mouse Methodology: Male C57BL/6 mice were chosen as an experimental object and were divided into 5 groups randomly selection. The normal group did not receive any induction. The control group was treated with normal saline in melanoma-induced' mice. Sample I group induced the upper part of Cervus elaphus Linne' extract in melanoma-induced mice. Sample II group was induced the middle part of Cervus elaphus Linne' extract in melanoma-induced mice. Sample III group was induced the lower part of Cervus elaphus Linne' extract in melanoma-induced mice. The dosage of medication was 0.2cc daily for 14days. Results: 1. There was a significant difference in the number of lymphocyte in spleen in the sample I (upper part of Cervus elaphus Linne' extract induced) and the sample II (middle part of Cervus elaphus Linne' extract induced) compared to the control group and the sample III (lower part of Cervus elaphus Linne' extract induced). On the other hand, no significant difference was observed in the number of lymphocyte in blood in the control group and all sample groups. 2. In the CD4+ T cell ratio in blood, all three sample groups showed differences compared to the control group, though there was no significant difference between sample groups. In the CD4+ T cell ratio in spleen, there was a difference between the sample I and the control group, while the sample II and the sample III had significant difference to the control group. And also, it has been observed there were differences between the sample I and the other samples. 3. In the CD8+ T cell ratio in spleen, all three sample groups showed significant differences compared to the control group, while there was no difference between groups in the ratio in blood. 4. In the CD4+/CD8+ T cell ratio in blood, the sample I showed a significant difference compared to the control group, while the sample 1I and sample III showed differences compared to the control group. In the CD4+/CD8+ T cell ratio in spleen, all three samples showed a significant difference compared to the control group, when the sample I had a difference to the other sample groups. 5. The spleen index of the sample I and the sample II showed a significant difference compared to the sample III and the control group. In comparison between the sample groups, the sample I and the sample II showed a significant difference to the sample III. 6. In terms of the change in body weight and melanoma weight, all three sample groups showed a significant difference compared to the control group, while the comparison between the sample groups showed the sample and the sample II had a significant difference to the sample Ⅲ. 7. In comparison of NK cell activity, the sample I had a difference compared to the other groups when the effector to target cell ratio was 2.5:1. With the ratio of 5:1, the sample I and sample II showed significant differences compared to the control group, while the sample Ⅲ showed a difference. When the effector to target cell ratio was 10:1, there was no difference between groups. 8. In the productivity of IL-2, all three sample groups showed significant differences compared to the control group. In comparison between sample groups, there were significant differences between each sample groups in order of the sample I , the sample II and the sample Ⅲ. Conclusion: As one can witness from the above results, administration of partial Cervus elaphus Linne extract played important role in antitumoral immune response in melanoma-induced mice, and it could be suggested that sample I and sample II groups have prominent antitumoral immune effect.

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A Study on the Improvement of Air-Fuel Ratio Control Performance in Sl Engine Using STR (STR을 이용한 가솔린 엔진의 공연비 제어 성능 향상에 관한 연구)

  • 신규철;박승범;윤팔주;정남훈;선우명호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.57-64
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    • 2001
  • This study presents an self tuning regulator(STR) to improve the air-fuel ratio control of performance of gasoline engine. The STR is designed based on the nonlinear dynamic engine model, and the performance of the STR is evaluated through the simulation and experiments. The STR shows better performance than a conventional PI controller in terms of the response time and disturbance rejection. Since the STR has less calculation load than the complex nonlinear controller, this algorithm can be easily applied to on-board engine controller.

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Control Bandwidth Extension Method Based on Phase Margin Compensation for Inverters with Low Carrier Ratio

  • Wei, Qikang;Liu, Bangyin;Duan, Shanxu
    • Journal of Power Electronics
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    • v.18 no.6
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    • pp.1760-1770
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    • 2018
  • This paper presents a control bandwidth extension method for inverters with a low carrier ratio. The bandwidth is extended at the price of decreasing the phase margin. Then the phase margin is compensated by introducing an extra leading angle into an inverse Park transformation. The model of the controller with the proposed method is established. The magnitude and phase characteristics are also analyzed. Then the influence on system stability when the leading angle is introduced is analyzed. The proposed method is applied to design an inverter controller with both a large bandwidth and a desired phase margin, and the experimental results verify that the controller performs well in the steady-state and in terms of transient response.

Statistical Design of CV-CUSUM Control Chart Using Fast Initial Response (FIR을 이용한 CV-CUSUM 관리도의 통계적 설계)

  • Lee, Jung-Hoon;Kang, Hae-Woon;Hong, Eui-Pyo;Kang, Chang-Wook
    • Journal of Korean Society for Quality Management
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    • v.38 no.3
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    • pp.313-321
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    • 2010
  • The coefficient of variation represents the ratio of the standard deviation to the mean, and it is a useful statistic for comparing the degree of variation from one data series to another, even if the means are drastically different from each other. Recently, the CV control chart is developed for monitoring processes in such situations. However, the CV control chart has low performance in detecting small shift. Due to the development of equipment and technique, currently, small shift of process occurs more frequently than large shift. In this paper, we proposes the CV-CUSUM control chart using CUSUM scheme which is cumulative sum of the deviations between each data point and a target value to detect a small shift in the process. We also found that the FIR(fast initial response) CUSUM control chart is especially valuable at start-up or after a CV-CUSUM control chart has signaled out-of-control.

A Study on Mixture Preparation in a Port Fuel Injection Sl Engine During Engine Starting (흡기포트 분사방식의 가솔린 엔진에서 냉시동시 혼합기 형성에 관한 연구)

  • 황승환;이종화;민경덕
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.4
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    • pp.15-22
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    • 2002
  • As the emission regulations on the automobiles have been increasingly stringent, precise control of air/fuel ration is one of the most important issues on the gasoline engines. Although many researches have been carried out to identify the fuel transport phenomena in the port fuel injection gasolines, mixture preparation in the cylinder has not been fully understood due to the complexity of fuel film behavior, In this paper, the mixture preparation during cold engine start is studied by using a Fast Response Flame ionization Detector.(FRFID) In order to estimate the transportation of injected fuel from the intake port into cylinder, the wall wetting fuel model was used. The two coefficient($\alpha$,$\beta$) of the wall-wetting fuel model was determined from the measured fuel mass that was inducted into the cylinder at the first cycle after injection cut-in. $\alpha$( ratio of directly inducted fuel mass into cylinder from injected fuel mass) and $\beta$ (ratio of indirectly inducted fuel mass into cylinder from wall wetted fuel film on the wall) was increased with increasing cooling water temperature. To reduce a air/fuel ratio fluctuation during cold engine start, the appropriate fuel injection rate was obtained from the wall wetting fuel model. Result of air/fuel ratio control, air/fuel excursion was reduced.

Microprocessor-Based Digital Controller Design with changing the Damping Ratio (감쇄비 변화를 마이크로프로세서로 이용한 계수형 제어기의 설계)

  • 정태원;김명환
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.19 no.1
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    • pp.35-40
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    • 1982
  • As a general-purpose device, the microprocessor has made a large impact on many area of engineering, In this paper, a controller has been implemented using microprocessors allowing the damping ratio ζ to be changed dynamically in control systems. The results show definite improvement in response time.

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