• Journal of Electrical Engineering and Technology
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• 제7권5호
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• pp.672-680
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• 2012

This paper proposes the control strategy of the shunt Flexible AC Transmission System (FACTS) devices to improve transient stability in multimachine power system. The multimachine power system has high nonlinear response after severe disturbance. The concept of Lyapunov energy function is applied to derive nonlinear control strategy and it was found that the time derivative of line voltage is not only can apply to control the shunt FACTS devices in multimachine system but also is locally measurable signal. The fuzzy logic control is also applied to overcome the uncertainty of various disturbances in multimachine power system. This paper presents the method of investigating the effect of the shunt FACTS devices on transient stability improvement. The proposed control strategy and the method of simulation are tested on the new England power system. It was found that the shunt FACTS devices based on the proposed nonlinear control strategy can improve transient stability of multimachine power system.

• Journal of Korean Neurosurgical Society
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• 제29권7호
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• pp.886-890
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• 2000

Objective : placement of ventricular catheter is important to achieve long-term patency of the shunt system. We describe a method of calculating the insertion site, trajectory, and the length of the ventricular catheter using CT parameters in shunt surgery. Patients and Methods : These can be rapidly obtained using a caliper from a scout cut and two axial scans at lateral ventricular and upper 3rd ventricular level. To compare this technique with traditional one, we analyzed 40 consecutive patients who underwent shunt surgery. Results : Of 20 patients undergoing ventriculoperitoneal shunt insertion using this technique, none had poor location of the proximal catheter. In the counterpart, 9 patients had poor location(p＝0.001). The number of patients who required revision surgery were also lower in the group using this technique, but it was not statistically significant (4 versus 2, p＝0.422). Mean follow-up period was shorter in this technique group. Conclusion : This technique provides an accurate placement of the proximal catheter without special instrument or additional expenses.

• Journal of Korean Neurosurgical Society
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• 제50권2호
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• pp.143-146
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• 2011

A ventriculo-peritoneal shunt is a standard surgical management for hydrocephalus, but complications may impede the management of this disease. Obstruction of the catheter is one of the most common complications and manifests clinically in various ways. Intraparenchymal cyst development after shunt malfunction has been reported by several authors, but the underlying mechanism and optimal treatment methods are debatable. The authors report a case of intraparenchymal cyst formation around a proximal catheter in a premature infant after a ventriculo-peritoneal shunt and discuss its pathogenesis and management.

• 한국전기전자재료학회논문지
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• 제31권2호
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• pp.107-111
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• 2018

In this study, we designed the temperature coefficient of resistance (TCR) and heat radiation properties of shunt fixed resistors by adjusting the atomic composition of a metal alloy resistor, and fabricated a resistor that satisfied the designed properties. Resistors with similar atomic composition of copper and nickel showed low TCR and excellent shunt fixed resistor properties such as short-time overload, rated load, humidity load, and high temperature load. Finally, we expect that improved sensor accuracy will be obtained in current-distribution-type shunt fixed resistor for IoT sensors by designing the atomic composition of the metal alloy resistor proposed in this work.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1502-1507
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• 2015

This paper deals with shunt compensation to eliminate voltage violation and enhance transfer capability, which is motivated towards implementation in the Korean power system. The optimal shunt compensation algorithm has demonstrated its effectiveness in terms of voltage accuracy and reducing the number of actions of reactive power compensating devices. The main shunt compensation devices are capacitor and reactor. Effects of control devices are evaluated by cost computations. The control objective at present is to keep the voltage profile of a key bus within constraints with minimum switching cost. A robust control strategy is proposed to make the control feasible and optimal for a set of power-flow cases that may occurs important event from system. Case studies with metropolitan area of the Korean power system are presented to illustrate the method.

• Journal of Yeungnam Medical Science
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• 제3권1호
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• pp.163-169
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• 1986

Intrapulmonary shunt was measured by $^{99m}Tc$-MAA perfusion tung scan. The study was included 76 patients. Significant amount of intrapulmonary shunt was observed in the pulmonary disease patients and liver disease patients. The shunt amount was correlated well with $PaO_2$ and $AaDO_2$ level. Further study is needed to search the various factors affecting the amount of intrapulmonary shunt.

• Journal of Korean Neurosurgical Society
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• 제43권3호
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• pp.159-161
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• 2008

A cerebrospinal fluid hydrothorax is a very rare complication following ventriculoperitoneal (VP) shunt and usually reported in children. We report a case of 47-year-old woman who developed massive hydrothorax and respiratory distress following intrathoracic migration of distal shunt catheter. After the confirmation of catheter in thoracic cavity using radionuclide shuntogram, the patient was successfully treated with laparoscopic shunt catheter reposition.

• Journal of Korean Neurosurgical Society
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• 제41권5호
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• pp.314-317
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• 2007

Ventriculoperitoneal [VP] shunt is a common treatment for hydrocephalic patients. However, complications, such as shunt tube occlusion, infection, intracranial hemorrhage, seizure can occur. Of these, intracranial hemorrhage may occur due to intracranial vascular injury or a rapid decrease of intracranial pressure [ICP]. Most of these hemorrhages are subdural hematomas [SDH] while a few are epidural hematomas [EDH]. It is extremely rare for an intracranial hemorrhage to occur due to an extension of the bleeding from an injured extracranial vessel. We report two cases of EDH due to occipital artery injury following VP shunt and extraventricular drainage [EVD].

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권1호
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• pp.31-34
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• 2004

This paper presents the fabrication and testing of a two-way pressure regulation micro shunt valve with an anti-siphon effect that can be implanted in hydrocephalus patients. This micro shunt valve consists of a silicone rubber membrane and a valve seat for the opening pressure control as well as the anti-siphon behavior. The two-way pressure regulation and the anti-siphon effect of the micro shunt valve are verified experimentally for various sizes of membranes and valve seats.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.127-132
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• 2001

In this paper, transmitted sound reduction performance of smart panels is studied according to different piezoelectric materials with piezoelectric shunt damping. Peizo-damping is implemented by using a newly proposed tuning method. This method is based on electrical impedance model and maximizing the dissipated energy at the shunt circuit. By measuring the electrical impedance at the piezoelectric patch bonded on a structure, an equivalent electrical model is constructed near the system resonance frequency. After shunting elements are connected to the equivalent circuit, the shunt parameters are optimally searched based on the criterion of maximizing the dissipated energy at the shunt circuit. Transmitted sound reduction performance is compared according to different piezoelectric materials with peizo-damping. Two piezoelectric materials are selected: PZT-5 and QuickPack IDE actuator. When resonant shunt circuit is considered, the use of PZT-5 exhibited the good sound reduction performance.