• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.981-984
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• 2005

현재, 영상처리에 있어서 잡음을 제거함과 동시에 영상의 에지성분을 보존하는 필터링 방법에 대한 연구가 활발히 진행되고 있다. 그리고 임펄스 노이즈 환경에서는 SM(standard median) 필터가우수한 잡음 제거 성능을 나타내었으나, 영상의 에지성분에 대한 오류가 발생하고 있다. 이에 따라, SM 필터를 개선한 다양한 방법들이 제안되었으며, CWM(center weighted median) 필터가 대표적이다. 또한, 에지의 보존이나 처리속도의 관점에서 더욱 향상된 성능을 나타내기 위한 방법으로 min-max 연산에 기반한 방법들이 있다 본 논문에서는 임펄스 노이즈에 의해 훼손된 화소에 대해, 그 화소를 둘러 싼 surrounding band의 최대 또는 최소 값을 이용하여 처리하였으며, 시뮬레이션을 통해 제안한 필터의 성능을 기존의 방법과 비교하였다.

• 상하수도학회지
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• 제35권2호
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• pp.113-120
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• 2021

High voltage impulse (HVI) has been gained attention as an alternative technique that could control the CaCO₃ scale problems encountered in water main, pipe, cooling tower and heat exchanger vessels. The aim of this study was to investigate the effect of electric field (E) and contact time (t) of HVI on reduction of Ca²⁺ concentration at two different temperatures of 25℃ and 60℃. A kinetic model on the effect of E and t was investigated too. As the E and t increased, the Ca²⁺ concentration decreased more than that of the control (= no HVI). The Ca²⁺ concentration decreased up to 81% at 15 kV/cm at 60℃, which was nearly 2 times greater than the control. With these experimental data-set of reduction of Ca²⁺ concentration under different E and t, the kinetic model was developed. The relationship between E and t required to reduce the concentration of Ca²⁺ by 30% was modeled at each temperature. The empirical model equations were; E^0.83· t = 60.3 at 25℃ and E^0.08· t = 1.1 at 60℃. These equations state the products of Eⁿ and t is always constant, which means that the required contact time can be reduced in accordance with the increment of E and vice versa.

• 한국정보통신학회논문지
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• 제25권8호
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• pp.1039-1045
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• 2021

4차 산업 혁명과 IoT 기술의 발전으로 카메라 센서와 영상에 기반한 자동화 시스템이 다양한 분야에서 사용되고 있으며, 영상 및 신호처리의 관심이 높아지고 있다. 본 논문은 임펄스 잡음에 훼손된 영상을 복원하기 위한 디지털 필터 알고리즘을 제안한다. 제안한 알고리즘은 영상에 설정된 로컬 마스크를 기준으로 수직, 수평, 대각선 방향으로 8개의 마스크로 분할하며, 각 분할 마스크의 표준편차를 비교하여 기준값을 구한다. 최종 출력은 공간적 거리에 따른 가중치와 기준값을 사용한 가중치를 로컬 마스크에 적용하여 계산한다. 제안한 알고리즘을 평가하기 위해 기존 알고리즘과 시뮬레이션하였으며, 확대영상과 PSNR 등을 이용하여 성능을 비교하였다.

• 한국임상약학회지
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• 제30권4호
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• pp.250-258
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• 2020

Background: Dopamine receptor agonists (DRAs) have been associated with impulse control disorders (ICDs) in Parkinson's disease (PD) in preliminary studies. Whether the association holds true when DRAs are used to treat non-PD, such as restless legs syndrome, prolactinoma, and several mood disorders is uncertain. Objective: The present study aimed to understand the research gaps related to the risk of ICDs associated with pramipexole or ropinirole (PRX/ROP) use as a treatment for specific underlying diseases, excluding Parkinson's disorders. Methods: We conducted a scoping review, systematically searching databases to identify literature on the types, prevalence, and factors associated with ICD in non-PD patients receiving PRX/ROP. All relevant information that helped understand the epidemiology of ICDs among non-PD patients taking PRX/ROP were extracted and analyzed. We also evaluated the potential associations between PRX/ROP and ICDs, utilizing the Naranjo scale or statistical analysis, depending on the type of literature. Results: We included 24 articles (19 case reports or case series and 5 population-based studies) in this scoping review. Evaluating the 19 case reports or case series using Naranjo scores led to the discovery of a possible link between PRX/ROP exposure and ICDs. However, important information to assess causality is frequently missing. Moreover, the population-based studies lack diversity in the study populations and enough study samples to draw conclusive results. Conclusion: Our scoping review suggests that the currently available literature requires more details in future case reports and for well-powered studies in various disease conditions where PRX/ROP is frequently used.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.725-728
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• 2002

In this Paper, a mathematical model describing the dynamics of pilot operated pressure control valve was derived. A attempt to analyze the Parameters(seat diameter, cone angle, spring stiffness, control volume) which relate to the performance of the object valve was carried out. Simulation using AMESim as a simulation tool was operated, and verified the validity of our simulation by means of comparison our simulation results with an experimental results of the pilot operated pressure control valve.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2005년도 추계학술대회 논문집
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• pp.159-162
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• 2005

Recently, due to rapid developments of wireless communication and digital TV, modern society needs to process of aquisition, storage and transmission of much information. So the importance of signal processing is increasing and various digital filters are used in the two-dimensional signal such as image. And kinds of these digital filters are IIR(infinite impulse response) filter and FIR(finite impulse response) filter. And FIR filter which has the phase linearity, the easiness of creation and stability is applied to many fields. In design of this FIR filter, flatness property is a important factor in pass-band and stop-band. In this paper, we designed a 2-D Circular FIR filter using the Bernstein polynomial, it is presented flatness property in pass-band and stop-band. And we simulated the designed filter with noisy test image and compared the results with existing methods.

• 수산해양교육연구
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• 제7권1호
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• pp.111-126
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• 1995

In general, the electromagnetic transient phenomenon always exists in induction motor(IM) with the torque change. The control performance of IM is very worse than that of D.C motor owing to this transient phenomenon. So many studies about the elimination methods of the transient phenomenon have been making progress. Interesting methods of them are the Field acceleration method(FAM) and the method of impulse addition on the input voltage at the time point of torque change. In this paper, first, the circuit equation of IM is derived from the phase segregation method. The torque equation consisted of the stator and rotor currents is derived from the solving of the circuit equation. As we well known, the transient terms exist in this the torque equation. The method of impulse addition on the input voltage at the instance of torque change is confirmed theoretically for the elimination of the transient phenomenon. With the base on it, the author proposed a real time algorithm to eliminate the transient terms. The control system is consisted of the PI controller with the feedforward of torque change. The author could confirm that the quick stepwise responses of torque and speed can be obtained from response simulations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2532-2537
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• 2005

FIR(Finite Impulse Response) filter is well known to be ideal for the finite time state-space model, but it requires much computation due to its inherent non-recursive structure especially when the measurement interval grows to a large extent. And often a fixed-lag smoother based on the finite time interval is needed to monitor the soundness of the system model and the measurement model, but the computation burden of FIR-type smoother imposes much restriction of its usage for real-time application. Conventional recursive forms of FIR estimator[1]-[4] could not be used for real time applications, since they are numerically unstable in their recursive equations. To cope with this problem, we suggest a stable recursive form FIR estimator(SRFIR) and its usefulness is demonstrated for designing the real-time fixed-lag smoother on the finite time window through an example of detection of rate bias in the anti-aircraft gun fire control system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.505-510
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• 1994

To prevent the stable states from the complex dynamics, the global behavior of the overall system must be considered. Thus, indirect adaptive scheme might result in needless responses. Discrete-time variable structure controllers for a well-known logistic map are designed for two deferent sliding hyperplanes. Impulse disturbances are fully rejected by tile virtue of discrete-time variable structure control(DVSC). A numerical example is given to illustrate the effectless of the DVSC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.127-129
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• 1997

In this paper, an active magnetic bearing-based motor-generator(M-G) system is designed and controlled by using DSP devices. Several experiments including start-up test, impulse test, whirl test, and generator load test are conducted using digital PID algorithm and AC power of about 58Hz, 100V, 0.8A can be generated from the M-G set.