• The Journal of the Acoustical Society of Korea
• /
• v.19 no.4
• /
• pp.93-100
• /
• 2000

Target signal feature parameters are very important to classify target by active sonar. Two highly correlated broad band pulses separated by time T have a time separation pitch(TSP) of 1/T Hz which is equal to the trough-to-trough or peak-to-peak spacing of its spectrum. In this study, TSP informations which represent feature of each target signal were effectively extracted by the FFT. The extracted TSP feature parameters were also applied to the pattern recognition algorithm to classify target and to analyze their properties.

• Journal of Astronomy and Space Sciences
• /
• v.22 no.4
• /
• pp.513-526
• /
• 2005

The objectives of this study are to perform extensive analysis on internal mass motion for a wider parameter space and to provide suitable design criteria for a broader applicability for the class of spinning space vehicles. In order to examine the stability criterion determined by a perturbation method, some numerical simulations will be performed and compared at various parameter points. In this paper, Ince-Strutt diagram for determination of stable-unstable regions of the internal mass motion of the spinning thrusting space vehicle in terms of design parameters will be obtained by an analytical method. Also, phase trajectories of the motion will be obtained for various parameter values and their characteristics are compared.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11b
• /
• pp.382-384
• /
• 2005

소프트웨어 테스팅에서 테스트 스위트(suite)의 수를 줄이면서도 테스트 커버리지나 오류검출에 있어서 효과적인 방법을 찾기 위한 많은 연구가 시도되어 왔다. 안정성이 높은 설계가 되도록 설계 조건을 결정하기 위하여 제어인자들의 직교 배열을 사용하는 시험방법인 교호작용 테스팅 기법이 소프트웨어의 테스트에서도 효과가 매우 높다는 것이 실험으로 증명되고 있다. 소프트웨어는 상대적으로 몇 안 되는 조건들의 조합들로 오류가 발생할 가능성이 높다는 특징을 가지고 있다. 따라서, 파라미터 간 교호작용 강도 t를 갖는 t-way 테스팅을 통해 효과적으로 테스트 스위트를 줄이면서 많은 오류를 검출할 수 있다. 그러나 t값을 증가시키면 테스트 스위트의 수가 늘어난다는 단점이 발생한다. 또한, 어떠한 파라미터들이 서로 교호작용을 일으키는 것인지 알수 없는 상황을 가정한 단순한 교호작용 테스팅은 자칫 서로 관련 없는 파라미터들도 교호작용 테스팅에 참여하기 때문에 테스트의 낭비가 있을 수 있다는 단점이 있다. 이에, 본 논문에서는 소프트웨어의 입력과 출력간의 관계를 바탕으로 시스템 I-O관계도를 작성한 후, 이를 바탕으로 각 출력에 대한 교호작용을 일으킬 수 있는 파라미터를 중심으로 테스트 스위트를 생성하는 Selective Covering Array를 제안한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.9
• /
• pp.57-64
• /
• 2004

The Purpose of this paper is to obtain the lateral-directional controllability and stability derivatives of the Velocity-173 from the flight test data and to simulate motion of the aircraft by using In-flight Real-Time Parameter Estimation Techniques. In this paper, the results of the In-Flight Real-Time parameter Estimation Techniques are compared with the results of the Advanced Aircraft Analysis. As a result, Estimation by using In-Flight Real-Time Parameter Estimation Techniques can be done rapidly and their results are reliable.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.8
• /
• pp.689-701
• /
• 2011

The relations between ambient conditions and ice accretion shapes are quantitatively analyzed by employing self-organization maps and analysis of variance. Liquid water contents(LWC), mean volumetric droplet diameter(MVD), ambient temperature and free-stream velocity are chosen as ambient conditions which change ice accretion shapes. The parameters of ice accretion shape are selected as maximum thickness, icing limits, ice heading, and ice accretion area. Qualitative analysis was conducted by employing self-organization maps which show the qualitative relations between ice shapes and ambient conditions. The quantitative results of analysis of variance yield intensity of ambient conditions to the parameters of ice accretion shapes.

• Annual Conference on Human and Language Technology
• /
• 1999.10e
• /
• pp.184-190
• /
• 1999

본 논문에서는 Text-to-Speech 시스템에서 사용할 억양 모델을 위해 음성 DB에서 모델 파라미터와 피치 검색테이블(lookup-table)을 추출하여 미리 구성하고, 합성시에는 이를 추정하여 최종 F0 값을 생성하는 자료기반 접근방식(data-driven approach)을 사용한다. 어절 경계강도(break-index)는 경계강도의 특성에 따라 고정적 경계강도와 가변적 경계강도로 세분화하여 사용하였고, 예측된 경계강도를 기준으로 억양구(Intonation Phrase)와 액센트구(Accentual Phrase)를 설정하였다. 특히, 액센트구 모델은 인지적, 음향적으로 중요한 정점(peak)을 정확하게 모델링하는 것에 주안점을 두어 정점(peak)의 시간축, 주파수축 값과 이를 기준으로 한 앞뒤 기울기를 추정하여 4개의 파라미터로 설정하였고, 이 파라미터들은 CART(Classification and Regression Tree)를 이용하여 예측규칙을 만들었다. 경계음조가 나타나는 조사, 어미는 정규화된(normalized) 피치값과 key-index로 구성되는 검색테이블을 만들어 보다 정교하게 피치값을 예측하였다. 본 논문에서 제안한 억양 모델을 본 연구실에서 제작한 음성합성기를 통해 합성하여 청취실험을 거친 결과, 기존의 상용 Text-to-Speech 시스템에 비해 자연스러운 합성음을 얻을 수 있었다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.3 no.4
• /
• pp.23-27
• /
• 2010

This paper performs emotion classification test to find out the best parameter of electroencyphalogram(EEG) signal. Linear predictor coefficients, band cross-correlation coefficients of fast Fourier transform(FFT) and autoregressive model spectra are used as the parameters of 10-channel EEG signal. A multi-layer neural network is used as the pattern classifier. Four emotions for relaxation, joy, sadness, irritation are induced by four university students of an acting circle. Electrode positions are Fp1, Fp2, F3, F4, T3, T4, P3, P4, O1, O2. As a result, the Linear predictor coefficients showed the best performance.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.2
• /
• pp.241-250
• /
• 2023

In this paper, when using the LMS algorithm for adaptive ultrasonic beamforming system, the effect of initial value setting on the margin of step parameters was studied. To this end, quasi-ideal beams, rotational beams with arbitrarily set beam widths were used as examples. In the numerical simulations, an arbitrary initial value(the number of sound sources fixed to any number) was set in the ultrasonic beamforming system, and the margin of the step parameter and convergence characteristics thereof were compared.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.391-393
• /
• 2021

In this paper, we introduce a long short-term memory (LSTM)-based fall detection system using TensorFlow that can detect falls occurring in the elderly in daily living. 3-axis accelerometer data are aggregated for fall detection, and then three types of parameter are calculated. 4 types of activity of daily living (ADL) and 3 types of fall situation patterns are classified. The parameterized data applied to LSTM. Learning proceeds until the Loss value becomes 0.5 or less. The results are calculated for each parameter θ, SVM, and GSVM. The best result was GSVM, which showed Sensitivity 98.75%, Specificity 99.68%, and Accuracy 99.28%.

• Journal of Korean Society of Transportation
• /
• v.29 no.6
• /
• pp.97-106
• /
• 2011

Mode choice model is an essential element for estimating- the demand of new means of transportation in the planning stage as well as in the establishment phase. In general, current demand analysis model developed for the mode choice analysis applies common parameters of utility function in each region which causes inaccuracy in forecasting mode choice behavior. Several critical problems from using common parameters are: a common parameter set can not reflect different distribution of coefficient for travel time and travel cost by different population. Consequently, the resulting model fails to accurately explain policy variables such as travel time and travel cost. In particular, the nonlinear logit model applied to aggregation data is vulnerable to the aggregation error. The purpose of this paper is to consider the regional characteristics by adopting the parameters fitted to each area, so as to reduce prediction errors and enhance accuracy of the resulting mode choice model. In order to estimate parameter of each area, this study used Household Travel Survey Data of Metropolitan Transportation Authority. For the verification of the model, the value of time by marginal rate of substitution is evaluated and statistical test for resulting coefficients is also carried out. In order to crosscheck the applicability and reliability of the model, changes in mode choice are analyzed when Seoul subway line 9 is newly opened and the results are compared with those from the existing model developed without considering the regional characteristics.