• 해양환경안전학회지
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• 제21권5호
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• pp.501-506
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• 2015

본 연구는 물때에 따른 교통특성을 분석하여 선박통항관리 개발에 필요한 자료를 제공하고자 한다. 목포항의 1년간 선박자동식별장치 자료를 사용하였다. 물때에 따른 교통량을 분석하기 위해 목포항의 1년간의 선박자동식별장치의 양력 데이터를 음력으로 변환한 후, 서해안의 구전 물때를 적용하였다. 연구 결과, 출항선박은 2-3물때 교통량이 7물때 보다 약 23-24 % 많고, 입항선박은 12-13물때 교통량이 9물때 보다 약 29-33 % 많았다. 특히, 시간의 변화에 따른 물때별 변동지수는 sine 함수의 형태로 변화하였다. 본 연구는 물때에 따른 선박통항관리 개발에 필요한 기초자료로 활용될 수 있을 것으로 판단된다.

• 한국컴퓨터정보학회논문지
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• 제14권8호
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• pp.25-31
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• 2009

RGB 모델을 통한 정적인 추론 규칙을 적용한 기존의 색채 정보 인식 방법은 RGB 모델이 가지는 인간 시각과의 괴리감과 특정한 환경에서만 적용할 수 있는 문제점이 있다. 본 논문에서는 HSI 모델을 적용하여 색채에 대한 인간 인식 과정과 유사한 형태의 추론 방식과, 사용자에 의해서 추론 규칙을 추가, 수정, 삭제 할 수 있는 방법을 제안한다. 본 논문에서는 각각의 H, S, I 소속 구간에 대하여 H는 Sine, Cosine 함수를 사용하여 소속 구간을 설계하며, S, I는 삼각형 타입의 소속 함수로 설계한다. 설계된 각각의 소속 구간에 대하여 소속 구간 병합을 적용하여 소속도를 계산하고, 계산된 결과들은 미리 제시된 추론 규칙에 적용하여 색채를 추론한다. 제안된 두가지 방법을 적용하여 실험한 결과, 기존의 방법보다 제안된 방법이 비교적 직관적이며 효율적인 형태로 결론을 도출할 수 있음을 확인하였다.

• 한국멀티미디어학회논문지
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• 제21권8호
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• pp.952-959
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• 2018

Clustering is one of the most fundamental algorithms in machine learning. The performance of clustering is affected by the distribution of data, and when there are more data or more dimensions, the performance is degraded. For this reason, we use a stacked auto encoder, one of the deep learning algorithms, to reduce the dimension of data which generate a feature vector that best represents the input data. We use k-means, which is a famous algorithm, as a clustering. Sine the feature vector which reduced dimensions are also multi dimensional, we use the Euclidean distance as well as the cosine similarity to increase the performance which calculating the similarity between the center of the cluster and the data as a vector. A deep clustering networks combining a stacked auto encoder and k-means re-trains the networks when the k-means result changes. When re-training the networks, the loss function of the stacked auto encoder and the loss function of the k-means are combined to improve the performance and the stability of the network. Experiments of benchmark image ad document dataset empirically validated the power of the proposed algorithm.

• 정보처리학회논문지B
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• 제8B권5호
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• pp.565-572
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• 2001

위치와 주파수 불확실성 곱이 작은 해석함수는 영상처리와 압축에 많은 장점이 있다. 지금까지의 불확실성원리에 기초하여 이 값을 계산하였으나, 이러한 측정은 최대 응답주파수가 0 이 아닌 인간시각필터에서 적절한 주파수 불확실성의 측정방법이 될 수 없다. 최대 응답을 갖는 주파수에 대한 주파수 불확실성을 계산하는 새로운 측정방법을 이용하여 결합유효폭을 유도하고자 한다. 결합변수가 커지면 많은 함수들의 결합유효폭이 0.5로 수렴하는 해석 결과를 얻었으며, 고려 대상 중에서 Gabor cosine 함수가 우수한 성능을 보였다.

• 한국음향학회지
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• 제15권5호
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• pp.61-64
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• 1996

본 논문에서는 귀의 주요한 특징인 주파수가중특성과 Bark-scale이라는 비선형주파수특성을 선형주파수축상에서 고려한 거리함수를 정의하고, 이 거리함수로부터 새로운 LPC cepstrum 계수를 제안한다. 귀의 특성은 선형주파수축에서 로그 스펙트럼에 대한 가증함수로서 표현되며, 이 가중함수는 cepstrum 영역에서 콘볼루션으로 표현되어 콘볼루션적으로 가중되는 LPC cepstrum을 정의하게 된다. 제안된 cepstrum 계수에서 정의된 가중함수는 A-weighting의 영향과 비선형주파수축의 영향을 하나의 가중함수로 통합하여 사용된 것이다. 제안된 파라미터의 성능을 음성인식 실험을 통하여 검증하였다.

• Advances in nano research
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• 제9권3호
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• pp.147-156
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• 2020

This research is related to nonlinear stability analysis of advanced microbeams reinforced by Graphene Platelets (GPLs) considering generic geometrical imperfections and thermal loading effect. Uniform, linear and nonlinear distributions of GPLs in transverse direction have been considered. Imperfection sensitivity of post-bucking behaviors of the microbeam to different kinds of geometric imperfections have been examined. Geometric imperfection is first considered to be identical as the first buckling mode, then a generic function is employed to consider sine-type, local-type and global-type imperfectness. Modified couple stress theory is adopted to incorporate size-dependent behaviors of the beam at micro scale. The post-buckling problem is solved analytically to derive load-amplitude curves. It is shown that post-buckling behavior of microbeam is dependent on the type geometric imperfection and its magnitude. Also, post-buckling load can be enhanced by adding more GPLs or selecting a suitable distribution for GPLs.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2043-2051
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• 2006

This paper considered identification of vibration characteristics of flexible structure with vector channel periodic lattice filter. We present an algorithm for AR coefficients for the vector-channel lattice filters, and characteristic equation and transfer function are derived from these coefficients. Vibration lattice filter is then constructed from the vector channel lattice filter, and performance of this vibration filter is tested with a test signal which is a combination of many sine waves to compare the performance of scalar and vector channel lattice. Also it is applied to the cantilever data to identify properties of the system, such as natural frequencies and damping ratios, to show its performance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.718-721
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• 2007

The ionic-polymer-metal-composite actuators have the best merit for bio-mimetic locomotion because of their large bending performance. Especially, they have the advantage for mimicking a fish-like motion because IPMCs are useful to be actuated in water. So we have developed IPMC actuators with multiple electrodes for realization of biomimetic motion. This actuator is fabricated by combining electroless plating and electroplating techniques capable of patterning precisely and controlling a thickness of Pt electrode layer. The FRF analysis was conducted by a mechanical shaker and direct electrical excitation which is based on sweep sine wave function. From this result, the proper young‘s modulus of Platinum was investigated and applied on expecting the vibration characteristics of patterned IPMC actuator. The calculated maximum displacement of the patterned IPMC was 2.32mm under an applied 4mN/mm. The natural frequency was increased however displacement was decreased in according to increase a thickness of Pt.

• 소성∙가공
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• 제9권3호
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• pp.304-312
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• 2000

An inverse finite element approach is employed to efficiently design the optimum blank shape and intermediate shapes from the desired final shape in multi-stage elliptic cup drawing processes. The multi-stage deep-drawing process is difficult to design with the conventional finite element analysis since the process is very complicate with the conventional finite element analysis since the process is very complicated with intermediate shapes and the numerical analysis undergoes the convergence problem even with tremendous computing time. The elliptic cup drawing process needs much effort to design sine it requires full three-dimensional analysis. The inverse analysis is able to omit all complicated and tedious analysis procedures for the optimum process design. In this paper, the finite element inverse analysis provides the thickness strain distribution of each intermediate shape through the multi-stage analysis. The multi-stage analysis deals with the convergence among intermediate shapes and the corresponding sliding constraint surfaces that are described by the analytic function of merged-arc type surfaces.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.950-955
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• 2001

For the development of an ultra-precision CNC polishing system including on-machine measurement system, we study a corrective polishing algorithm. We analyze and test the unit removal profiles for a ball type polishing tool. Using these results we calculate dwell time distributions and residual errors for a target removal shape. We use the polishing simulation method and feed rate calculation method for the dwell time calculation. We test corrective polishing algorithm with an optical glass. The target removal shape is a sine wave that has amplitude 0.3 micro meters. We find this polishing process has a machining resolution of nanometer order and is effective for sub-micrometer order machining. This result will be used for the software development of the CNC polishing system.