• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.4
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• pp.303-307
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• 2007

This paper investigated the effect of the pad buffing process on the material removal characteristics and pad stabilization during silicon chemical mechanical polishing. The pads surface were controlled by the buffing process using a buffer made by the sandpaper. The buffing process is based on abrasive machining by using a high speed sandpaper. The controlled pad by the buffing process show less deformation deviation and stable material removal rate during the CMP process. In addition, the controlled pad ensure better uniformity of removal rate than comparative pads. As a result of monitoring, the controlled pad by the buffing process demonstrated constant and stable friction force signals from initial polishing stage. Therefore, the tufting process could control the pad surface to be uniform and improve the performance of the polishing pad.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.13-15
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• 2004

In this paper, we propose a novel stability criterion and a guideline of controller design for switched linear systems. Unlike existing criterions such as Lie algebraic method and multiple Lyapunov functions method, the proposed criterion can be applied to each individual system without considering an overall system. By applying the proposed criterion to each individual system separately, a state feedback controller can be easily designed. Stability of the overall system is proved by developing a rule to determine non-increasing Lyapunov functions recursively at each switching instant. An illustrative example is given.

• Journal of Power System Engineering
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• v.18 no.4
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• pp.112-116
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• 2014

Roll and pitching motions of a vessel can seriously degrade the performance of mechanical systems and the effectiveness of personnel. Many studies on roll stabilization and trimming control system design have focused on stabilizing the vessel through the use of fins, tanks, rudders and flaps. However the ultimate objective of such approaches must be to improve boarding sensitivity. This paper presents an anti-seasickness bed that consists of a rotator and bearing system that does not make use of electric power. The advantages of this system are its simple construction, usefulness, and safe operation. In this study, the rotation angles of the upper plate of a bed according to change weight of the rotator have been calculated to determine the stability. As a result, it can be concluded that proposed stabilizing bed can be of practical use in the field.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.27-28
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• 2016

본 논문은 BESS-디젤발전기 연계운전 조건에서 BESS의 안정한 전류제어를 수행하기 위해 전향보상 성분을 고려하여 디지털 이론 기반의 전류제어 안정도를 해석하고, 시뮬레이션 및 실험을 통해 검증하였다. 디젤발전기의 동기 인덕턴스가 LCL 필터에 미치는 상호간섭 공진문제를 해석하였으며, 불안정한 전류제어의 안정도 향상을 위해 적절한 이득을 갖는 전향보상을 고려하였다. 또한, BESS-디젤발전기 연계운전 실험을 통해 전향보상 이득이 0.4인 경우 안정한 전류제어가 수행됨에 따라 안정도 해석의 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.123-124
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• 2015

Recently interest on DC systems has been grown up extensively for more efficient connection with renewable energy. During the operation, there happens DC_link voltage variations. This paper focuses on the DC voltage stabilization applied in stand-alone DC microgrid to improve the system stability by keeping the voltage within limits. Batteries and a variable speed diesel generator cover the shortage of power after all available renewable energy is consumed. Load shedding or power generation reduction should automatically takes place if the maximum tolerable voltage variation is exceeded. PSIM based simulation results are presented to evaluate the performance of the proposed control measures.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.327-331
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• 2006

본 논문은 엔터테인먼트 4족 보행로봇에 관한 것으로 24개의 자유도와 비접촉온도 3축 모션, 터치, 음성인식, CCD 카메라와 IR 센서를 내포하고 있다. 4족 보행로봇을 비평탄지형에서 안정되게 보행시키기 위한 알고리즘과 원격지에서 로봇을 제어하기 위한 알고리즘을 제안한다. 제안한 보행안정화 알고리즘은 다양한 센서들을 이용하여 불확실한 환경 하에서 안정된 보행이 되도록 하였으며, PC 상의 GUI와 음성인식 시스템을 이용하여 로봇을 무선으로 원격제어하게 하였다. 개발한 4족 보행로봇의 실험을 통하여 제안한 알고리즘을 검증하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.364-366
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• 2012

Quantification of acoustic amplification in a model chamber has been studied for combustion stabilization induced by passive control devices. DMD(Dynamic mode Decomposition) method is adopted and the results from method are compared with those from damping factor approach. The model chamber has a faceplate with baffled injectors, where damping factor has its maximum at a specific baffle gap. They show a good agreement with the results from the previous method.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.325-330
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• 2008

LRT System Application Project is performed for the purpose of technical advancement and stabilization of K-AGT system from the viewpoint of practical use and commercialization. For those purpose, the performance test and evaluation procedure for K-AGT signaling system are developed, and the scheme of verifying the performance and function of signaling system under multi-train and driverless control environment is being conducted. For the multi-train operation in K-AGT test track, we applied the regenerative energy storage system in addition to the existing electric facilities. This paper present the design, manufacturing, and testing results of regenerative energy storage system.

• Journal of Trauma and Injury
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• v.34 no.3
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• pp.198-202
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• 2021

Super-selective renal artery embolization is an increasingly popular technique for the management of traumatic, low-grade renal trauma. When performed in distal arterial branches, this intervention enables tissue preservation and arrest of hemorrhage, but it may not be practical in cases of multifocal, high-grade renal injuries. In such cases, surgical nephrectomy remains the more common treatment modality to ensure hemodynamic control. We present the unique case of a patient who presented in hemorrhagic shock following a major trauma that resulted in a grade 5 renal injury treated with complete renal artery embolization using Gelfoam, resulting in hemodynamic stabilization. Interestingly, imaging 1 month after embolization revealed residual enhancement of the inferior pole of the kidney, suggesting reconstitution of flow and partial renal salvage. Ultimately, transcatheter "nephrectomy" with careful selection of a temporary embolic agent may serve as a safe and efficient alternative to surgical nephrectomy with the added possibility of preserving partial renal perfusion and function in the emergent setting.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.404-405
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• 2019

본 논문에서는 PMSM(Permanent magnet synchronous motor)의 MTPA(Maximum Torque Per Ampere) 운전을 고려한 V/f 제어 시 안정화 기법에 대해 제안한다. PMSM은 V/f 제어 시 부하 변동에 따라 탈조할 가능성이 있다. 제안된 기법은 안정도 개선을 위해 추정된 q축 전류를 이용하여 부하 변동정보를 얻고 이를 바탕으로 고정자 주파수를 변동하여 회전자 속도가 동기속도를 유지할 수 있는 안정화 기법을 적용하였다. 제안된 안정화 기법으로 저속 영역부터 약자속 영역까지 부하변동에도 안정적인 운전이 가능하도록 하였다. 1kW SPMSM의 모의실험을 통하여 제안된 기법의 효용성을 검증하였다.