• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.276-276
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• 2000

This paper presents the efficient algorithms for the pose determination of a circular object with and without a priori knowledge of the object radius. The developed algorithms valid for a circular object are the result of the elaboration of Ma's work [2], which determines the pose of a conic object from two perspective views. First, the geometric constraint of a circular object and its projection on the image plane of a camera is described. The number of perspective views required for the object pose determination with and without a priori knowledge of the object radius is also discussed. Second, with a priori knowledge of the object radius, the pose of a circular object is determined from a single perspective view. The object pose information, expressed by two surface normal vectors and one position vector, is given in a closed form and with no ambiguity. Third, without a priori knowledge of the object radius, the pose of a circular object is determined from two perspective views. While the surface normal vectors are obtained from the first view, the position vector is obtained from the two views.

• 동양고전연구
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• 제35호
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• pp.275-295
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• 2009

이 글은 그레이엄 (A. C. Graham)이 후기묵가의 저작인 "묵경"에서 보이는 필(必)과 선지(先知)를 각각 '논리적 필연성'과 '선험적 지식'(a priori knowledge)으로 보는 해석을 비판하기 위한 것이다. 그레이엄은 묵가의 논리학을 '이름과 대상을 짝짓는' '기술의 학'(論)과 '이름과 이름간의 관계를 따지는' '추론의 학'(辯)으로 나누고 특히 후자에 대해 비록 그것이 서구의 형식논리학은 아니지만, 유클리드 기하학과 같은 엄밀한 증명의 과정으로 보아야 한다고 하였다. 이러한 그의 주장들은 지식을 그 대상에 따라 명지(名知)와 합지(合知)로 나누어보는 데서 출발한다. 그러나 내가 보기에 기술의 학과 이름의 학은 후기묵가의 저작인 "묵경"안에서 명확히 구분될 수 없고, 게다가 묵가의 선지(先知)와 이 선지(先知)가 가진 필연성은 기본적으로 논리적 필연성이 아니라 규범적 필연성 및 경험적 필연성의 개념이다. 규범적 필연성은 중국의 정명(正名)사상에서 제시된 '규범적 정의이론'으로부터 기인하는 것이다. 규범적 정의이론이란 기술적 정의이론과는 달리 규범적으로 개념을 정의하는 것이다. 예컨대 '아버지는 자애롭다'의 정의는 형태는 기술적이나 사실은 '아버지는 자애로워야한다'의 규범적인 것이다. 이러한 규범적 정의이론을 통해 경험적 지식은 그것이 지식인한 당연히 필연적으로 오류 불가능임이 주장된다. 한마디로 묵가에서는 경험적 지식이 추론적 지식 혹은 선험적 지식보다 항상 더 우선적이기에 묵가의 선험적 지식은 사실 엄밀하게 선험적인 것이 아니고, 이러한 지식이 갖는 필연성도 규범적 필연성 및 경험적 필연성에 불과하다.

• 한국어교육
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• 제28권2호
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• pp.209-233
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• 2017

The purpose of this study is to analyze the pragmatic functions of '-ketun(yo)' expressed in the discourse associating with the context of communication based on the actual conversations of Korean native speakers. As discourse is closely related to the context, contextual factors surrounding the discourse should be actively considered in order to reveal the function of grammar expressed in the discourse. Also, there is need to consider the grammatical functions in terms of the linguistic user which is the subject of interaction in the discourse. Based on this necessity, in this study, we analyzed the pragmatic functions of '-ketun(yo).' As a result, '-ketun(yo)-' had a great influence on the formation and expansion of the shared context in communication contexts. The shared context is expanded through generative mutual knowledge and priori mutual knowledge. As a result of the conversation analysis, '-ketun(yo)-' was used at a high frequency in the expansion of generative mutual knowledge formation. In addition, '-ketun(yo)-' appeared to have a discourse cohesion function that binds topics with other topics. In the case that '-ketun(yo)-' is formed through priori mutual knowledge, '-ketun(yo)-' could be used as a sign to lead the union of the speaker and the listener. This study has significance in that it examines the pragmatic functions of '-ketun(yo)-' in relation to the context of communication based on actual utterance.

• ETRI Journal
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• 제43권6호
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• pp.966-977
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• 2021

Filterbank multicarrier with offset quadrature amplitude modulation (FBMC-OQAM) is an attractive alternative to the orthogonal frequency division multiplexing (OFDM) modulation technique. In comparison with OFDM, the FBMC-OQAM signal has better spectral confinement and higher spectral efficiency and tolerance to synchronization errors, primarily due to per-subcarrier filtering using a frequency-time localized prototype filter. However, the filtering process introduces intrinsic interference among the symbols and complicates channel estimation (CE). An efficient way to improve the CE in FBMC-OQAM is using a technique known as windowed frequency domain averaging (FDA); however, it requires a priori knowledge of the window length parameter which is set based on the channel's frequency selectivity (FS). As the channel's FS is not fixed and not a priori known, we propose a k-nearest neighbor-based machine learning algorithm to classify the FS and decide on the FDA's window length. A comparative theoretical analysis of the mean-squared error (MSE) is performed to prove the proposed CE scheme's effectiveness, validated through extensive simulations. The adaptive CE scheme is shown to yield a reduction in CE-MSE and improved bit error rates compared with the popular preamble-based CE schemes for FBMC-OQAM, without a priori knowledge of channel's frequency selectivity.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1859-1865
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• 2002

In the conventional sliding mode control technique, a priori knowledge of the bound of external disturbances or/and parameter uncertainties is required to assure control robustness. This, however, may not be easy to obtain in practical situation. This work presents a novel methodology, a sliding mode controller with perturbation estimator, which offers a robust control performance without a priori knowledge about the perturbations (disturbances and parameter uncertainties). The proposed technique is featured by an integrated average value of the imposed perturbation over a certain sampling period. In order to demonstrate the effectiveness of the proposed methodology, a two-link robotic system is adopted and its position control performance is evaluated. In addition, a comparative work between the conventional technique and the proposed one is undertaken.

• International Journal of Precision Engineering and Manufacturing
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• 제3권4호
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• pp.94-100
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• 2002

The conventional sliding mode control (SMC) technique requires a priori knowledge of the upperbounds of disturbances and/or modeling uncertainties to assure robustness. This, however, may not be easy to obtain in practical situation. This paper presents a new methodology, a sliding mode control with disturbance estimator (SMCDE), which offers a robust control performance without a priori knowledge about the disturbance. The proposed technique is featured by an average value of the imposed disturbance over a certain period. A nonlinear spring-mass-damper system and a two-link robot system are adopted as illustrative application examples. Control performances such as estimation error and tracking error are compared between the proposed methodology and conventional scheme.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.782-787
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• 2004

In the conventional sliding mode control technique, a priori knowledge of the bound of external disturbances or/and parameter uncertainties is required to assure control robustness. This, however, may not be easy to obtain in practical situation. This work presents a novel methodology, a sliding mode controller with perturbation estimator, which offers a robust control performance without a priori knowledge about the perturbations (disturbances and parameter uncertainties). The proposed technique is featured by an integrated average value of the imposed perturbation over a certain sampling period. This work also proposes two effective actuating methods of the perturbation estimator: on-off condition and filtering condition. In order to demonstrate the effectiveness of the proposed methodology, a two-link robotic system is adopted and its position control performance is evaluated. In addition, a comparative work between the conventional technique and the proposed one is undertaken.

• 한국정밀공학회지
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• 제19권1호
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• pp.165-171
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• 2002

The conventional sliding mode control(SMC) technique requires a priori knowledge of the upperbounds of disturbances or/and modeling uncertainties to assure robustness. This, however, may not to be easy to obtain in practical situation. This paper presents a new methodology, sliding mode control with disturbance estimator(SMCDE), which offers a robust control performance without a priori knowledge about the disturbance. The proposed technique is featured by an average value of the imposed disturbance over a certain period. A nonlinear spring-mass-damper system is adopted as an illustrative example, and a comparative work between the conventional technique and the present one is undertaken.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.1085-1088
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• 1999

This paper presents a method for soccer scene analysis and coordinate transformation from scene to ground model using a priori knowledge. First, the ground and spectator regions are separated, and various objects are extracted from the separated ground region. Second, an affine model is used for mapping the object positions on the soccer image into the position on the ground model. Problems regarding holes arising from mapping processing are solved using inverse mapping instead of a usual interpolation method. Experiments are performed on a PC using about 100 RGB images acquired at 240＊640 resolution and 3∼5 frames per second.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.1222-1229
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• 1993

An advanced design environment , which is based on adaptive and knowledge -based finite elements (INTELMESH), has been developed. Unlike other approaches, INTEMMESH incorporates the information about the object geometry as well as the boundary and loading conditions to generate an ${\alpha}$-priori finite element mesh which is more refined around the critical regions of the problem domain. INTEMMESH is designed for planar domains and axisymmetric 3-D structures of elasticity and heat transfer subjected to mechanical and thermal loading . It intelligently identifies the critical regions/points in the problem domain and utilize the new concepts of substructuring and wave propagation to choose the proper mesh size for them. INTEMMESH generates well-shaped triangular elements by applying trangulartion and Laplacian smoothing procedures. The adaptive analysis involves the intial finite elements analyze and an efficient ${\alpha}$-posteriori error analysis involves the initial finite element anal sis and an efficient ${\alpha}$-posteriori error analysis and estimation . Once a problem is defined , the system automatically builds a finite element model and analyzes the problem though automatic iterative process until the error reaches a desired level. It has been shown that the proposed approach which initiates the process with an ${\alpha}$-priori, and near optimum mesh of the object , converges to the desired accuracy in less time and at less cost. Such an advanced design/analysis environment will provide the capability for rapid product development and reducing the design cycle time and cost.