• 정보저장시스템학회논문집
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• 제1권1호
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• pp.84-92
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• 2005

This work presents the feasibility of shunt damping far vibration suppression of the rotating HDD disk-spindle system using piezoelectric bimorph. A target vibration mode which significantly restricts the recording density increment of the drive is determined through modal analysis and a piezoelectric bimorph is designed to suppress unwanted vibration. After deriving the two-dimensional generalized electromechanical coupling coefficient of the shunted drive, the shunt damping of the system is predicted by simulating the displacement transmissibility using the coefficient. In addition, optimal design process using sensitivity analysis is undertaken in order to improve the shunt damping of the system. The effectiveness of the proposed methodology is verified through experimental implementation by observing the vibration characteristics of the rotating disk-spindle system in frequency domain.

• Advances in pediatric surgery
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• 제13권2호
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• pp.212-216
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• 2007

Migration of a peritoneal catheter of a ventriculoperitoneal shunt into the scrotum is a rare complication. We treated a case of catheter migration in the scrotum. A 12-year old boy, who had had a ventriculoperitoneal shunt at the age of 4 months due to neonatal hydrocephalus, visited the outpatient clinic because of a right inguinal hernia. On physical examination, a firm mass was found in the left scrotum. Pelvic X-ray demonstrated a coiled catheter in the left scrotum. The catheter was successfully removed by exploring the left patent processus vaginalis after high ligation of the hernia sac. This case suggests a suction action of the patent processus vaginalis and the possibility of catheter migration long after shunt catheter insertion.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.9-11
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• 2003

In power system planing and operation, voltage and reactive power control are very important. The voltage deviation and system losses can be reduced through control of reactive power sources. In general, there are several different reactive power sources, we used UPFC and switched shunt capacitor to improve the voltage profile and to reduce system losses in this study. Since there are many switched shunt capacitors in power system, so it is necessary to coordinate these switched shunt capacitors. In this study, Genetic Algorithm(GA) is used to find optimal coordination of UPFC and switched shunt capacitors in a local area of power system. In case study, the effectiveness of the proposed method is demonstrated in KEPCO's power system. The simulation is performed by PSS/E.

• 반도체디스플레이기술학회지
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• 제14권3호
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• pp.57-60
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• 2015

Electric power in large devices is controlled by digital circuits, such as switching mode power supply. This kind of power circuits require accurate current sensor for power distribution. We studied characteristics of shunt resistor, which has many advantages for commercial application compared to Hall-effect current sensor. We applied ceramic package to the shunt resistor. Ceramic package has good thermal conductivity compared to plastic package, and this point is important for space requirement in Printed Circuit Board (PCB). Another advantage of the ceramic package is that surface mount technology (SMT) can be used for production. Our experimental results showed that the ceramic packaged resistor showed about 50% lower temperature than the plastic packaged one. Burning point and frequency characteristics are also discussed.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 봄 학술발표회 논문집
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• pp.470-477
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• 2002

Possibility of passive piezoelectric damping based on a new shunting parameter estimation method is studied using finite element analysis. The adopted tuning method is based electrical impedance that is found at piezoelectric device and the optimal criterion for maximizing dissipated energy at the shunt circuit. Full three dimensional finite element model is used for piezoelectric devices with cantilever plate structure and shunt electronic circuit is taken into account in the model. Electrical impedance is calculated at the piezoelectric device, which represents the structural behavior in terms of electrical field, and equivalent electrical circuit parameters for the first mode are extracted using PRAP (Piezoelectric Resonance Analysis Program). After the shunt circuit is connected to the equivalent circuit for the first mode, the shunt parameters are optimally decided based on the maximizing dissipated energy criterion. Since this tuning method is based on electrical impedance calculated at piezoelectric device, multi-mode passive piezoelectric damping can be implemented for arbitrary shaped structures.

• Journal of Power Electronics
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• 제7권3호
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• pp.257-264
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• 2007

Active power filters can be cost-effective for use in practical systems with the insertion of a few passive elements in shunt or series configuration. The resulting hybrid filters can be designed to provide dominant lower order harmonic elimination and reactive power support by the passive elements so that the burden on the active filter counterpart is reduced. In this paper, the rate reduction in the shunt active filter is estimated when it is connected in parallel with suitable passive tuned harmonic filters. The active filtering system is based on an appropriate control scheme. The simulation and the experimental results of the shunt active filter, along with the estimated value of reduction in rating, show that the hybrid shunt filtering system is quite effective in compensating for the harmonics and reactive power, in addition to being cost-effective.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.655-657
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• 1996

The objective of this paper is to compare the series and shunt approaches of controlled reactive power compensation to improve power system transient stabilities. Including main circuit considerations of series and shunt compensators, application aspects are thought to have major impacts on efficiency and economy of the installation of the compensators. The concept is studied by means of EMTP simulations on one machine-Infinite Bus Test System which consists of a 612MVA steam turbin generator and transformer and double circuit 345KV transmission line. Idealized dynamic models of Thyristor Controlled Series Compensation and Shunt Compensation are used for the comparative study of the series and shunt compensation approach to damp power system oscillations.

• Journal of Korean Neurosurgical Society
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• 제66권3호
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• pp.274-280
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• 2023

Post-hemorrhagic hydrocephalus (PHH) in preterm infant is common, life-threatening and the main cause of bad developmental outcomes. Ventriculoperitoneal (VP) shunt is used as the ultimate treatment for PHH. Low birth weight and low gestational age are the combination of worse prognostic factors while the single most important prognostic factor of VP shunting is age. Aggressive and early intervention have better effect in intraventricular hemorrhage and intracranial pressures control. It reduces infection rate and brain damage resulted in delayed shunt insertion. It is extremely important to let PHH infants get older and gain weight to have internal organs to be matured before undergoing VP shunt. As premature infants undergo shunt after further growth, shunt-related complications would be reduced. So temporary surgical intervention is critical for PHH infants to have them enough time until permanently shunted.

• Journal of Power Electronics
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• 제13권2호
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• pp.232-242
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• 2013

To obtain phase currents information in AC drives, shunt sensing technology is known to show great performance in cost-effectiveness and therefore it is widely used in low cost applications. However, shunt sensing methods are unable to acquire phase currents in certain operation conditions. This paper deals with the derivation of the boundary conditions for phase current reconstruction in three-shunt sensing inverters and proposes a voltage injection method to expand the measurable areas. As the boundary conditions are deeply dependent on the switching patterns, they are typically analyzed on the voltage vector plane for space vector pulse width modulation (SVPWM) and discontinuous pulse width modulation (DPWM). In the proposed method, the voltage injection and its compensation are conducted within one sampling period. This guarantees fast current reconstruction and the injected voltage is decided so as to minimize the current ripple. In addition to the voltage injection method, a sampling point shifting method is also introduced to improve the boundary conditions. Simulation and experimental results are presented to verify the boundary condition derivation and the effectiveness of the proposed voltage injection method.

• 전자공학회논문지
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• 제49권9호
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• pp.35-42
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• 2012

개구면 결합 급전 방법을 이용하여 inductive loaded 마이크로스트립 패치 안테나를 설계하고 병렬 스터브를 이용하여 임피던스 대역폭을 넓히는 방법에 대해 연구하였다. 급전선로에 병렬 스터브를 삽입하여 AIMPA의 임피던스 대역폭을 확장시켰다. 병렬 스터브를 삽입한 AIMPA의 -10 dB 임피던스 대역폭은 5.51 %로 병렬 스터브를 삽입하지 않은 AIMPA의 임피던스 대역폭 2.4 %와 비교하여 대역폭이 약 129.6 % 증가함을 볼 수 있었다. -10 dB 대역폭 내에서 방사 패턴의 전체적인 모양은 크게 변화하지 않음을 확인하였다.