• 말소리와 음성과학
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• 제6권4호
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• pp.141-148
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• 2014

Voice is the most common means for communication, but some people have difficulties in generating voice due to their congenital or acquired disorders. Individuals with speech disorders might lose their speaking ability due to hearing impairment, encephalopathy or cerebral palsy accompanied by motor skill impairments, or autism caused by mental problems. However, they have needs for communication, so some of them use various types of AAC (Augmentative & Alternative Communication) devices in order to meet their communication needs. In this paper, a mobile application for literate people having speech disorder was designed and implemented by developing accurate and fast sentence-completion functions for efficient user interaction. From a user study and the previous study on Korean text-based communication for adults having difficulty in speech communication, we identified functionality and usability requirements. Specifically, the user interface with scanning features was designed by considering the users' motor skills in using the touch-screen of a mobile device. Finally, we conducted the usability test for the application. The results of the usability test show that the application is easy to learn and efficient to use in communication with people with speech disorders.

• 한국컴퓨터그래픽스학회논문지
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• 제3권1호
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• pp.37-47
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• 1997

본 논문에서는 운전 시뮬레이션의 한 요소인 배경교통의 생성을 위한 알고리듬을 제안한다. 각 배경차량은 교통신호등, 도로 주변 표지판, 차선 그리고 수변의 차들을 인지하며 교통규칙에 따라 지능적으로 움직이는 하나의 autonomous agent로 모델된다. 본 논문의 알고리듬은 현재 상용자가 운전하는 차의 주변만을 국소적으로 고려하여, 시뮬레이션되는 가상 도로 환경의 크기에 관계없이 일정한 양의 계산에 소요되도록 하였다. 배경차량의 단조로운 행동양식을 피하기 위하여, 여러 종류의 확률분포함수를 통해 인위적인 다양성을 보이도록 하였다. 결과적으로 도출된 배경차량의 행동양식은 매우 사실적인 것으로 판명되었다. 실험에 의하면, 본 논문에서 제안한 알고리듬을 통해 생성된 배경차량의 움직임과 사람의 직접 조종하는 차량의 움직임은 쉽게 구별될 수 없었다.

• Journal of the Korean Data and Information Science Society
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• 제24권3호
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• pp.495-504
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• 2013

진화 알고리즘 계산 지능을 이용한 예측 방법이 다목적 최적화 문제에서 많이 이용되고 있고, 이러한 방법들은 많은 근사 파레토 최적해들을 좀 더 정확하게 생성하기 위해서 개선되고 있다. 본 논문은 다목적 최적화 문제에서 서포트 벡터기계를 이용하여 근사 파레토 프런티어를 찾는 방법을 제안한다. 또한 제안된 방법과 진화 알고리즘을 결합한 것이 파레토 프런티어를 더 잘 근사시킨다는 것과 두 개혹은 세 개의 목적함수를 가진 의사결정은 제안된 방법으로 파레토 프런티어를 시각화한 것에 근거하여 더 쉽게 수행된다는 것을 보인다. 마지막으로 몇 개의 수치예제를 통해 제안된 방법의 효율성에 대해 보일 것이다.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.80-89
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• 2013

This paper presents an efficient approach for solving economic dispatch (ED) problems with nonconvex cost functions using a 'Mean-Variance Optimization (MVO)' algorithm with Kuhn-Tucker condition and swap process. The aim of the ED problem, one of the most important activities in power system operation and planning, is to determine the optimal combination of power outputs of all generating units so as to meet the required load demand at minimum operating cost while satisfying system equality and inequality constraints. This paper applies Kuhn-Tucker condition and swap process to a MVO algorithm to improve a global minimum searching capability. The proposed MVO is applied to three different nonconvex ED problems with valve-point effects, prohibited operating zones, transmission network losses, and multi-fuels with valve-point effects. Additionally, it is applied to the large-scale power system of Korea. The results are compared with those of the state-of-the-art methods as well.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.53-63
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• 2013

To guide the decision making of the expert engineer specialized in power system operation and control; the practical OPF solution should take in consideration the critical situation due to severe loading conditions and fault in power system. Differential Evolution (DE) is one of the best Evolutionary Algorithms (EA) to solve real valued optimization problems. This paper presents simple Differential Evolution (DE) Optimization algorithm to solving multi objective optimal power flow (OPF) in the power system with shunt FACTS devices considering voltage deviation, power losses, and power flow branch. The proposed approach is examined and tested on the standard IEEE-30Bus power system test with different objective functions at critical situations. In addition, the non smooth cost function due to the effect of valve point has been considered within the second practical network test (13 generating units). The simulation results are compared with those by the other recent techniques. From the different case studies, it is observed that the results demonstrate the potential of the proposed approach and show clearly its effectiveness to solve practical OPF under contingent operation states.

• Wind and Structures
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• 제29권6호
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• pp.389-403
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• 2019

In this study, two original spectral representations of stationary stochastic fields, say the continuous proper orthogonal decomposition (CPOD) and the frequency-wavenumber spectral representation (FWSR), are derived from the Fourier-Stieltjes integral at first. Meanwhile, the relations between the above two representations are discussed detailedly. However, the most widely used conventional Monte Carlo schemes associated with the two representations still leave two difficulties unsolved, say the high dimension of random variables and the incompleteness of probability with respect to the generated sample functions of the stochastic fields. In view of this, a dimension-reduction model involving merely one elementary random variable with the representative points set owing assigned probabilities is proposed, realizing the refined description of probability characteristics for the stochastic fields by generating just several hundred representative samples with assigned probabilities. In addition, for the purpose of overcoming the defects of simulation efficiency and accuracy in the FWSR, an improved scheme of non-uniform wavenumber intervals is suggested. Finally, the Fast Fourier Transform (FFT) algorithm is adopted to further enhance the simulation efficiency of the horizontal stochastic wind velocity fields. Numerical examplesfully reveal the validity and superiorityof the proposed methods.

• 한국통신학회논문지
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• 제34권6B호
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• pp.575-584
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• 2009

본 논문에서는 IP 기반 콜 센터에서 통화 처리 모의 실험을 위한 VoIP 트래픽 발생기를 설계하고 구현한다. 구현된 트래픽 발생기(VoIPTG)는 H.323과 SIP 기반의 VoIP 콜 생성과 G.711 코덱을 사용하는 RTP 트래픽을 발생시킴으로써 다수의 대화자들이 음성 통화하는 상황을 모의 실험을 할 수 있도록 해준다. VoIPTG를 이용하면 0.323 또는 SIP 세션 제어 프로토콜 선택, 사용자(call)수 변화, 시간 변화, 음성코덱의 선택 등 여러 가지 조합을 통해 다양한 모의실험 환경을 연출 할 수 있다. 이러한 트래픽 발생기는 IP 기반 컨택 센터의 전반적인 기능 검사 및 성능평가를 위해 유용하게 사용될 수 있으며, 특히 IP 기반 녹취 시스템의 성능 평가를 위해서 필수적이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.980-985
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• 1988

In this paper, a control system of the PUMA 560 robot manipulator using a PC (Personal Computer) is presented. The hardware of the designed control system is composed of IBM-PC/AT, interface board, selection board, interrupt generating circuit, and the servo control unit of the PUMA controller. A robot control library is developed using assembly and C language, and is composed of several low-level functions and arm interface routines, world model routines, arm kinematics routines, and motion command service routines. Using the designed library, joint interpolated motion and Cartesian interpolated motion of the PUMA robot manipulator are realized. In the future, our system is expected to be a very helpful basis and a useful tool for developing various control algorithms of robot manipulator using sensory information.

• 한국통신학회논문지
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• 제35권12B호
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• pp.1175-1182
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• 2010

본 논문에서는 항공기와 지상국 사이의 방위정보와 거리를 측정하는 전술항공운행 장비인 TACAN(tactical air navigation)을 위한 디지털 회로를 FPGA로 구현하였다. TACAN의 신호처리를 위한 모든 기능을 하나의 FPGA에 집적하여 구현하였다. 제안한 하드웨어는 입력 인터페이스, 레지스터 파일, 디코더, 신호 발생기, 그리고 주 제어기로 구성된다. 구현한 하드웨어는 TACAN이 요구하는 방위정보를 위한 펄스쌍 그룹을 생성하는 기능과 거리를 측정하기 위한 항공기 응답 기능을 모두 포함하고 있고, 그 밖에 지상국의 ID를 제공하는 기능 등을 모두 포함하였다. 제안한 하드웨어는 ALTERA의 FPGA를 이용하여 구현하였고, 7,071개의 logic element를 사용한다.

• Wind and Structures
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• 제7권2호
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• pp.107-130
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• 2004

This paper presents a time-domain approach for analyzing nonlinear random vibrations of long-span suspended cables under transversal wind. A consistent continuous model of the cable, fully accounting for geometrical nonlinearities inherent in cable behavior, is adopted. The effects of spatial correlation are properly included by modeling wind velocity fluctuation as a random function of time and of a single spatial variable ranging over cable span, namely as a one-variate bi-dimensional (1V-2D) random field. Within the context of a Galerkin's discretization of the equations governing cable motion, a very efficient Monte Carlo-based technique for second-order analysis of the response is proposed. This procedure starts by generating sample functions of the generalized aerodynamic loads by using the spectral decomposition of the cross-power spectral density function of wind turbulence field. Relying on the physical meaning of both the spectral properties of wind velocity fluctuation and the mode shapes of the vibrating cable, the computational efficiency is greatly enhanced by applying a truncation procedure according to which just the first few significant loading and structural modal contributions are retained.