• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.694-699
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• 2001

This paper presents a control of active suspension system for quarter-car model with two-degree-of-freedom using $H_{inf}$ and nonlinear adaptive robust control method. Suspension dynamics is linear and treated by $H_{inf}$ method which guarantees the robustness of closed loop system under the presence of uncertainties and minimizes the effect of road disturbance to system. An Adaptive Robust Control (ARC) technique is used to design a force controller such that it is robust against actuator uncertainties. Simulation results are given for both frequency and time domains to verify the effectiveness of the designed controllers.

• The Plant Pathology Journal
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• 제36권5호
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• pp.459-467
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• 2020

Areca palm yellow leaf (AYL) disease caused by the 16SrI group phytoplasma is a serious threat to the development of the Areca palm industry in China. The 16S rRNA gene sequence was utilized to establish a rapid and efficient detection system efficient for the 16SrI-B subgroup AYL phytoplasma in China by loop-mediated isothermal amplification (LAMP). The results showed that two sets of LAMP detection primers, 16SrDNA-2 and 16SrDNA-3, were efficient for 16SrI-B subgroup AYL phytoplasma in China, with positive results appearing under reaction conditions of 64℃ for 40 min. The lowest detection limit for the two LAMP detection assays was the same at 200 ag/μl, namely approximately 53 copies/μl of the target fragments. Phytoplasma was detected in all AYL disease samples from Baoting, Tunchang, and Wanning counties in Hainan province using the two sets of LAMP primers 16SrDNA-2 and 16SrDNA-3, whereas no phytoplasma was detected in the negative control. The LAMP method established in this study with comparatively high sensitivity and stability, provides reliable results that could be visually detected, making it suitable for application and research in rapid diagnosis of AYL disease, detection of seedlings with the pathogen and breeding of disease-resistant Areca palm varieties.

• Asian-Australasian Journal of Animal Sciences
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• 제33권4호
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• pp.531-538
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• 2020

Objective: Evidence from previous reports indicates that pig domestication in East Asia mainly occurred in the Mekong region and the middle and downstream regions of the Yangtze River. Further research identified two new origin centers for domestic pigs in the Tibetan Plateau and the islands of Southeast Asia. However, due to the small sample size of Tibetan pigs, details of the origin and spread of Tibetan pigs has not yet been established. Methods: We analyzed mitochondrial DNA control region (D-loop) variation in 1,201 individuals from nine Tibetan pig populations across five provinces. Comprehensive Tibetan pig samples were taken to perform the most detailed analysis of Tibetan pigs to date. Results: The result indicate that Rkaze pigs had the lowest level of diversity, while Changdu pigs had the highest diversity. Interestingly, these two populations were both in the Tibetan Plateau area. If we calculate diversity in terms of each province, the Tibetan Plateau area had the lowest diversity, while the Chinese province of Gansu had the highest diversity. Diversity gradient analysis of major haplotypes suggested three domestication centers of Tibetan pigs in the Tibetan Plateau and the Chinese provinces of Gansu and Yunnan. Conclusion: We found two new domestication centers for Tibetan pigs. One is in the Chinese province of Gansu, which lies in the upstream region of the Yellow River, and the other is in the Chinese province of Yunnan.

• 조명전기설비학회논문지
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• 제15권6호
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• pp.65-72
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• 2001

본 논문에서는 UPS용 인버터의 강인한 디지털제어를 위하여 인버터 출력측 LC필터의 커패시터 전압과 전류의 2중 제어루프로 구성된 새로운 제어기법을 제안한다. 제안된 전압·전류의 2중 제어루프는 전압 제어루프의 커패시터 전압을 전류 제어루프의 커패시터 전류의 위상중심으로 두고, 2중 데드비트 제어를 수행함으로써 커패시터 전류의 위상지연이 보상된 완전한 진상전류 제어가 가능하게 된다. 전류 제어루프는 디지털 제어기의 시간 지연요소를 시스템의 고유한 파라미터로 가정한 2차 데드비트 제어기로 설계하여 디지털 제어기의 고유한 연산 지연시간에 의한 성능저하를 개선한다. 또한, 외란에 의한 데드비트 제어의 영향을 제거하기 위하여 부하전류 예측기법을 전류 제어루프에 부가하여 외란을 피드포워드 보상함으로써 외란에 강인한 전류제어를 수행한다.

• Nuclear Engineering and Technology
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• 제39권4호
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• pp.327-336
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• 2007

The influence of density differences on the mixing of the primary loop inventory and the Emergency Core Cooling (ECC) water in the downcomer of a Pressurised Water Reactor (PWR) was analyzed at the ROssendorf COolant Mixing (ROCOM) test facility. ROCOM is a 1:5 scaled model of a German PWR, and has been designed for coolant mixing studies. It is equipped with advanced instrumentation, which delivers high-resolution information for temperature or boron concentration fields. This paper presents a ROCOM experiment in which water with higher density was injected into a cold leg of the reactor model. Wire-mesh sensors measuring the tracer concentration were installed in the cold leg and upper and lower part of the downcomer. The experiment was run with 5% of the design flow rate in one loop and 10% density difference between the ECC and loop water especially for the validation of the Computational Fluid Dynamics (CFD) software ANSYS CFX. A mesh with two million control volumes was used for the calculations. The effects of turbulence on the mean flow were modelled with a Reynolds stress turbulence model. The results of the experiment and of the numerical calculations show that mixing is dominated by buoyancy effects: At higher mass flow rates (close to nominal conditions) the injected slug propagates in the circumferential direction around the core barrel. Buoyancy effects reduce this circumferential propagation. Therefore, density effects play an important role during natural convection with ECC injection in PWRs. ANSYS CFX was able to predict the observed flow patterns and mixing phenomena quite well.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권2호
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• pp.184-189
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• 2014

In this paper, a new design method of vibration suppression controller for multi-inertia (especially, 3-ineritia) resonance systems is proposed. The controller consists of a digital fuzzy controller for speed loop and a digital PI controller for current minor loop. The three scaling factor of the fuzzy controller and two PI controller gains are determined by Differential Evolution (DE). The DE is one of optimization techniques and a kind of evolutionary computation technique. In this paper, we have applied the DE/rand/1/bin strategy to design the optimal controller parameters. Comparing with the conventional design algorithm, the proposed method is able to shorten the time of the controller design to a large extent and to obtain accurate results. Finally, we confirmed the effectiveness of the proposal method by the computer simulations.

• Journal of Electrical Engineering and Technology
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• 제4권3호
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• pp.405-409
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• 2009

A polarization-independent multiwavelength-switchable fiber filter is proposed based on a polarization beam splitter and fiber coupler, which can function as a polarization-independent transmission or reflection-type interleaving filter. The proposed filter consists of a polarization beam splitter and a Sagnac birefringence loop composed of a 50:50 coupler, high birefringent fibers, and two quarter-wave plates. In the proposed filter, a transmission-type interleaver with a channel isolation > 18 dB or a reflection-type one with a channel isolation of ${\sim}3$ dB, whose channel spacing and switching displacement were 0.8 and 0.4 nm in common, respectively, could be obtained. A channel interleaving operation could be performed by the proper control of waveplates within the Sagnac birefringence loop.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1613-1616
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• 2008

A Transcutaneous Energy Transmission System (TET) has been developed for the wireless energy transmission with two magnetically coupled coils. A resonance circuit is used to raise the induced voltage and current of the secondary coil. Its resonance frequency depends on the internal resistance of circuit and the transferred energy. Because the transferred energy usually changes in wide range, the output voltage is unstable and the energy transferring efficiency decrease. A push-pull class E amplifier is usedto generate high frequency AC voltage. To maintain proper resonance frequency, the voltage output of the amplifier was continuously monitored and adjusted to the optimized resonance frequency. Because of its high frequency (370 kHz), a phase lockedloop circuit and a comparator are used to monitor the output waveform. The results of experimentaldata show that the PLL circuit can increase the transmission efficiency and stabilize the output voltage of TET.

• Asian-Australasian Journal of Animal Sciences
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• 제20권3호
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• pp.313-315
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• 2007

Seventeen haplotypes were detected from the complete mitochondrial DNA control region sequences analyzed from eighty individuals of two Tibetan domestic sheep breeds. The nucleotide composition of all the sequences was 33.0% A, 29.7%T, 22.9%C and 14.4%G; G+C was 37.3%. The length of the sequences ranged from 1,107 bp to 1,259 bp. The difference between them was primarily due to 3-5 copy numbers of a 75 bp tandem repeat sequence. The NJ phylogenetic tree (the number of replications of bootstrap test is 1,000) presented three major domestic sheep lineages, which suggested that modern Tibetan sheep breeds are derived from three maternal sources.

• 전기학회논문지
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• 제66권1호
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• pp.40-47
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• 2017

In this paper, a small signal model for grid-connected inverter with unipolar pulse width modulation method is presented. Small-signal analysis allows to predict the stability and dynamics of the inverter. To regulate output voltage and to achieve power factor correction, inverter has two control loops. Loop gains are useful to identify the stability for multi-loop controlled system. Based on small-signal model, controllers are designed to improve audio susceptibility and output impedance characteristics. Proposed small-signal model and controllers are verified by PSIM simulation and experiments.