• 전자공학회논문지B
• /
• 제31B권8호
• /
• pp.11-19
• /
• 1994

The matching probability P(ο/$\lambda$), of the signal sequence(ο) observed for a finite time interval with a HMM (Hidden Markov Model $\lambda$) indicates the probability that signal comes from the given model. By utilizing the fact that the probability represents matching score of the observed signal with the model we can recognize an unknown signal pattern by comparing the magnitudes of the matching probabilities with respect to the known models. Because the algorithm however uses floating point variables during the computing process hardware implementation of the algorithm requires floating point units. This paper proposes an integer algorithm which uses positive integer numbers rather than float point ones to compute the matching probability so that we can economically realize the algorithm into hardware. The algorithm makes the model parameters integer numbers by multiplying positive constants and prevents from divergence of data through the normalization of variables at each step. The final equation of matching probability is composed of constant terms and a variable term which contains logarithm operations. A scheme to make the log conversion table smaller is also presented. To analyze the qualitive characteristics of the proposed algorithm we attatch simulation result performed on two groups of 10 hypothetic models respectively and inspect the statistical properties with repect to the model order the magnitude of scaling constants and the effect of the observation length.

• Journal of Power Electronics
• /
• 제15권6호
• /
• pp.1456-1467
• /
• 2015

This paper presents a novel close-loop control scheme based on small signal modeling and weighted composite voltage feedback for a three-phase input and single-phase output Matrix Converter (3-1MC). A small non-polar capacitor is employed as the decoupling unit. The composite voltage weighted by the load voltage and the decoupling unit voltage is used as the feedback value for the voltage controller. Together with the current loop, the dual-loop control is implemented in the 3-1MC. In this paper, the weighted composite voltage expression is derived based on the sinusoidal pulse-width modulation (SPWM) strategy. The switch functions of the 3-1MC are deduced, and the average signal model and small signal model are built. Furthermore, the stability and dynamic performance of the 3-1MC are studied, and simulation and experiment studies are executed. The results show that the control method is effective and feasible. They also show that the design is reasonable and that the operating performance of the 3-1MC is good.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 ITC-CSCC -2
• /
• pp.637-640
• /
• 2000

ERG signal represents the responses of the each layer of retina for the visual stimulus and accumulated responses according to the signal processing occurring in the retina. By investigating the reaction types of each wave of the ERG, various kinds of information for the diagnosis and the signal processing mechanisms in the retina can be obtained. In this paper, the ERG signal is generated by simulating of the volume conductor field of response of each retina layer and summing of them algebraically. The retina model used for simulation is Shah’s Computer Retina model which is one of the most reliable models recently developed. The generated ERG is compared with the typical ERG and shows a very close similarity. By changing the parameters of the retina model, the diagnostic investigation is performed with the variation of the ERG waveform.

• 한국음향학회지
• /
• 제20권2호
• /
• pp.44-51
• /
• 2001

본 연구에서는 능동소나와 관련된 시스템에 적용가능한 잠수함 수중표적의 표적강도 및 신호형태를 예측하는 반사신호 합성모델을 제안한다. 이는 입사각에 따라 외부헐로 하이라이트의 위치가 변하는 UTAHID (Underwater TArget by Highlight Distribution) 모델을 기초로 하여 잠수함 내부의 복잡한 형상에 의한 반사점들을 산란자운에 의한 구룹화된 하이라이트군으로 변형을 가하여 반사신호를 합성한다. 제안된 모델은 입사신호의 펄스길이 변화에 따른 표적강도 변화특성 및 합성신호 파형, 시간분산손실, 신장효과 등에 대해 분석하였으며, 이는 능동소나, 음향대항, 감시 시스템과 같이 반사신호 합성에 관련된 여러가지 실시스템에 적용이 가능하다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권4호
• /
• pp.2028-2041
• /
• 2019

Compressed sensing (CS) is a new theory. With regard to the sparse signal, an exact reconstruction can be obtained with sufficient CS measurements. Nevertheless, in practical applications, the transform coefficients of many signals usually have weak sparsity and suffer from a variety of noise disturbances. What's worse, most existing classical algorithms are not able to effectively solve this issue. So we proposed an efficient algorithm based on smoothed ${\ell}_0$ norm for sparse signal reconstruction. The direct ${\ell}_0$ norm problem is NP hard, but it is unrealistic to directly solve the ${\ell}_0$ norm problem for the reconstruction of the sparse signal. To select a suitable sequence of smoothed function and solve the ${\ell}_0$ norm optimization problem effectively, we come up with a generalized approximate function model as the objective function to calculate the original signal. The proposed model preserves sharper edges, which is better than any other existing norm based algorithm. As a result, following this model, extensive simulations show that the proposed algorithm is superior to the similar algorithms used for solving the same problem.

• 대한의용생체공학회:의공학회지
• /
• 제16권3호
• /
• pp.317-324
• /
• 1995

A need exists for the accurate identification of time series models having time varying parameters, as is important in the case of real time identification of nonstationary EMG signal. Thls paper describes real time identification and muscle fatigue monitoring method of nonstationary EMG signal. The method is composed of the efficient identifier which estimates the autoregressive parameters of nonstationary EMG signal model, and its real time implementation by using T805 parallel processing computer. The method is verified through experiment with real EMG signals which are obtained from surface electrode. As a result, the proposed method provides a new approach for real time Implementation of muscle fatigue monitoring and the execution time is 0.894ms/sample for 1024Hz EMG signal.

• 한국해양공학회지
• /
• 제28권1호
• /
• pp.55-63
• /
• 2014

In this paper, we propose an threshold-based Schur algorithm for estimating the media characteristics of sub-bottom multi-layers by using the signal generated by a parametric array transducer. We use the KZK model to generate a parametric array signal, and use the proposed threshold-based Schur algorithm for estimating the reflection coefficients of multiple sea bottom layers. Using computer simulation, we verify that the difference frequency component generated by the KZK model prevails over the signals of primary frequencies at long range. For the simulation, we use the transmit signal generated by the KZK and the reflected signal obtained from a lattice filter model for the seawater and sub-bottom of multi-level non-homogeneous layers. Through the simulation, we verify that the proposed threshold-based Schur algorithm can give much more accurate and efficient estimates of the reflection coefficients than methods using received signal, matched filter output signal, and normal Schur algorithm output.

• Journal of Electrical Engineering and Technology
• /
• 제8권3호
• /
• pp.658-665
• /
• 2013

While the chirp signal is extensively used in radar and sonar systems for target decision in wireless communication systems, it has not been widely used for positioning in indoor environments. Recently, the IEEE 802.15.4a standard has adopted the chirp spread spectrum (CSS) as an underlying technique for low-power and low-complexity precise localization. Chirp signal based ranging solutions have been established and deployed but their ranging performance has not been analyzed in multipath environments. This paper presents a ranging performance analysis of a chirp signal and suggests a method to suppress multipath error by using a type of non-linear chirp signal. Multipath ranging performance is evaluated using a conventional linear chirp signal and the proposed non-linear chirp signal. We verify the feasibility of both methods using two-ray multipath model simulation. Our results demonstrate that the proposed non-linear chirp signal can successfully suppress the multipath error.

• 한국정보통신학회논문지
• /
• 제14권7호
• /
• pp.1557-1564
• /
• 2010

감성신호는 개인에 따라 그 패턴이 매우 다르게 나타나므로, 본 논문에서는 감성신호의 개인별 특징을 고려한 최대 엔트로피 기반 감성 인식 모델을 제안한다. 제안하는 모델은 보다 정확하게 사용자의 감성을 인식하기 위해서, 단순히 주어진 입력 감성 신호 값만을 사용하지 않고, 긍정 감성 신호 값의 평균과 부정 감성 신호 값의 평균을 입력 감성 신호의 값과 비교하여 활용한다. 또한, 감성 인식에 대한 전문적인 지식이 없이도 감성 인식 모델의 구축이 용이하도록, 제안하는 모델은 성능이 높다고 잘 알려진 기계학습기법의 하나인 최대 엔트로피 모델을 이용한다. 감성 신호의 수치 값을 그대로 사용하면 기계 학습에 필요한 학습 패턴 자료를 충분히 확보하기 어렵다는 점을 고려하여, 제안하는 모델은 평균차를 수치 값 대신 +(양수)와 -(음수)로 단순하게 표현하며, 감성 반응 전체 시간인 10초 대신 초단위로 분할하여 학습 패턴 자료의 양을 늘렸다.

• 한국ITS학회 논문지
• /
• 제10권1호
• /
• pp.27-41
• /
• 2011

본 논문은 도시부 간선도로의 트램을 위한 고정식 우선신호 전략으로 트램의 연동모형 MAXBAND MILP-Tram을 제시하였다. MAXBAND MILP-Tram은 전통적인 간선도로 연동모형인 MAXBAND를 기반으로 하고 있으며, 중앙트램 전용 차로의 트램과 일반차로의 승용차 모두를 위한 이중화된 연동폭을 산정할 수 있다. 본 모형은 일반차량 대비 낮은 속도와 정류장 정차시간이 포함되는 통행시간을 가지는 트램 통행특성을 고려하여 연동폭을 산정할 수 있다. 중앙트램전용차로에서는 현시순서에 따라 트램의 녹색시간이 크기를 달리하게 되며, 이를 제약조건으로 표현하였다. 미시적 시뮬레이션 효과분석을 수행하여 트램 연동모형의 효과분석을 위한 트램과 교차로의 제어지체와 사람당 제어지체 변화를 확인하였다. MAXBAND MILP-Tram으로 산출된 신호시간을 VISSIM에 적용한 결과 MAXBAND MILP-2 대비 트램의 차량당 평균 제어지체는 57%가 감소된 결과를 나타내었으나, 교차로 평균 제어지체의 경우 일반차량의 연동폭이 감소함에 따라 MILP-Tram은 MILP-2 대비 18% 증가된 결과를 나타내었다. 또한 일반차량의 교통량 변화를 이용한 민감도 분석에서는과포화 상태에 근접함에 따라 MAXBAND MILP-Tram과 같이 �낵째� 현시순서만을 변경시키는 우선신호 기법은 사람당 지체를 감소시킬 수 있는 유용한 수단임을 확인하였다.