• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.115-118
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• 2010

본 논문은 추적레이더의 추적 오차를 예측하기위한 레이더 시뮬레이터 개발에 관한 것이다. 본 연구에서는 다중경로 전파특성, 표적 모델링, RPY 보상, DTM 지형데이터 등을 이용한 전파의 전파특성 분석을 통한 표적추적레이더의 추적 오차 요인을 분석하였다. 이를 바탕으로 추적 오차를 줄이기 위해 추적 레이더의 서보 특성과 서보 구동의 지연보상을 위한 $\alpha-\beta$ 필터를 사용하였다. 표적 추적레이더의 추적 상황을 종합적으로 고려하여 추적 상황을 정확히 예측할 수 있는 시뮬레이터를 구현 하였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.2
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• pp.31-37
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• 2001

Digital servo implementation in optical servo chip has been spotlighted since it is easy to integrate with other blocks and it has less sensitive characteristics change in terms of temperature variation and better flexibility to the system variation like pick-up. Therefore, Optical disc players adopted digital servo are increasing in market. However, one drawback of digital signal processor embedded digital servo is power consumption that is one of the most important factors of portable optical disc player system. For that reason, this paper introduces new architecture to reduce power consumption of digital servo by means of reducing DSP load but increasing minimum hardware size. The main idea of reducing power consumption of digital servo greatly is utilizing CDP characteristics as most operations are done and used up most operating steps of DSP at the initial time, but most power consumption is occurred in play mode. Therefore, if operating steps for digital filtering in play mode could be reduced greatly, power consumption of overall system can be reduced greatly. This paper shows an example that low power digital servo architecture whose current is reduced almost 83%, compare to that of digital servo which is not applied by the low power architecture introduced in this paper.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.05a
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• pp.115-121
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• 2002

PC 및 게임 소프트웨어의 급격한 발달로 가상현실 구현에 필요한 그래픽 환경은 성숙단계에 진입하였다. 현재 국내에서 개발되는 게임 소프트웨어는 PC사용자를 겨냥한 제품이 대부분이다. 토요일 휴무제의 도입에 따른 문화 콘텐츠 시장의 확대, 가족이 즐길 수 있는 테마 공원의 성장성 등을 고려할 때 기존의 PC 게임과 차별화 되는 운동감을 포함한 가상현실 게임 제품의 개발이 요망된다. 잘 알려진 6자유도 운동 시뮬레이션 방식인 Stewart 방식은 구현 가격이 고가이고 운동범위가 작아 게임용으로 상용화하기 어렵다. 본 연구에서는 2대의 AC 서보모터를 이용하여 roll과 pitch의 2자유도만 구현하나, 각 축으로 자유로운 회전이 가능하여 탑승자의 스릴감을 향상시킬 수 있는 저가형 운동의자를 개발하였다. 2 자유도로 회전하는 외부와 차단된 캐빈 내부에는 40인치 스크린과 프로젝터가 설치되어 롤러코스터 게임의 몰입감을 향상시켰다. 롤러코스터 가상현실을 대상으로 운동감을 극대화하기 위한 워시아웃 (washout) 필터의 설계 알고리즘이 제시된다. 탑승자들의 감성 평가를 객관화하기 위한 데이터 베이스 구축방안이 서술된다

• Journal of Intelligence and Information Systems
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• v.11 no.1
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• pp.107-121
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• 2005

Recently, many researches on recommendation systems and collaborative filtering have been proceeding in both research and practice. However, although product items may have multi-valued attributes, previous studies did not reflect the multi-valued attributes. To overcome this limitation, this paper proposes new methodology for recommendation system. The proposed methodology uses multi-valued attributes based on clustering technique for items and applies the collaborative filtering to provide accurate recommendations. In the proposed methodology, both user clustering-based CBR and item attribute clustering-based CBR technique have been applied to the collaborative filtering to consider correlation of item to item as well as correlation of user to user. By using multi-valued attribute-based clustering technique for items, characteristics of items are identified clearly. Extensive experiments have been performed with MovieLens data to validate the proposed methodology. The results of the experiment show that the proposed methodology outperforms the benchmarked methodologies: Case Based Reasoning Collaborative Filtering (CBR_CF) and User Clustering Case Based Reasoning Collaborative Filtering (UC_CBR_CF).

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2513-2515
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• 2005

Recently genetic algorithm techniques have widely used in adaptive and control schemes for production systems. However, generally it costs a lot of time for leaming in the case applied in control system. Furthermore, the physical meaning of genetic algorithm constructed as a result is not obvious. And this method has been used as a learning algorithm to estimate the parameter of a genetic algorithm used for identification of the process dynamics of Butter-Worth analog filter and it was shown that this method offered superior capability over the genetic algorithm. A genetic algorithm is used to solve the parameter identification problem for linear and nonlinear digital filters. This paper goal estimate Butter-Worth analog filter parameter using the genetic algorithm.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.15-17
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• 2005

Recently genetic algorithm techniques have widely used in adaptive and control schemes for production systems. However, generally it costs a lot of time for learning in the case applied in control system. Furthermore, the physical meaning of genetic algorithm constructed as a result is not obvious. And this method has been used as a learning algorithm to estimate the parameter of a genetic algorithm used for identification of the process dynamics of nonlinear IIR filter and it was shown that this method offered superior capability over the genetic algorithm. A genetic algorithm is used to solve the parameter identification problem for linear and nonlinear digital filters. This paper goal estimate nonlinear IIR filter parameter using the genetic algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.614-619
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• 1997

The hydraulic pressure pulsation has on the effected on the acoustic nosie and control performance of the hydraulic-servo system. The Helmholtz attenuator introduction on the hydraulic line is an efficient device to reduce the hydraulic pulsation. The salient feature of causing hydraulic pulsation and the frequency characteristics of Helmholtz attenuator are studied. The hydraulic filter design parameters such as the locating position, connecting orifice area and accumulator volume are mathematically analyzed. The instrumental works are carried out with the remarkable reduction of the hydraulic pressure pulsation magnitude and the acoustic noise level.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.502-504
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• 2005

Recently genetic algorithm techniques have widely used in adaptive and control schemes for production systems. However, generally it costs a lot of time for learning in the case applied in control system. Furthermore, the physical meaning of genetic algorithm constructed as a result is not obvious. And this method has been used as a learning algorithm to estimate the parameter of a genetic algorithm used for identification of the process dynamics of FIR filter and it was shown that this method offered superior capability over the genetic algorithm. A genetic algorithm is used to solve the parameter identification problem for linear and nonlinear digital filters. This paper goal estimate FIR filter parameter using the genetic algorithm.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.309-313
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• 1998

고성능 서보 전동기 시스템을 구축하기 위해서는 저속영역과 고속영역을 포함하는 넓은 속도영역에서의 정확한 속도검출을 통한 정밀한 속도제어기 필수적이며, 관성모멘트와 같은 전동기의 파라메터 변동에 대해 강인한 속도제어와 외란 억제능력도 중요한 요소로서 고려되어야 한다. 변동하는 부하의 관성모멘트을 식별하여 PI 속도제어기를 실시간으로 적응 동정하고, 플랜트 잡음과 측정잡음을 고려하는 상태 관측기인 칼만필터의 부하관성에 대한 민감성을 제거하기 위해 이를 적응 동정하여 적응 상태 추정기를 구현함으로써 우수한 속도 추정 성능을 얻었다. 또한 외란과 불확실한 모델링은 등가 외란으로 추정되어 전향적으로 보상된다. 본 논문에서는 이러한 특징을 이용하여 전동기의 고성능 속도제어를 구현하고 유도전동기를 이용한 실험을 통하여 연구결과의 유효성을 확인한다.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.420-422
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• 1998

In this paper, we propose a position-speed control of servo system with a state estimator. And also we utilized two mass modelling in order to deals with real system accurately. The overall control system consists of two parts: the position-speed controller and state estimator. The Kalman filter applied as state - feedback controller is an optimal state estimator applied to a dynamic system that involves random perturbations and gives a linear,unbiased and minimun error variance recursive algorithm to estimate the unknown state optimally. Therefore we consider the error problem about the servo system modelling, the measurement noise at low-speed ranges a stochastic system, and implement a optimal state observer. Performance of the proposed state estimator are demonstrated by computer simulations.