• 한국전자파학회논문지
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• 제28권8호
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• pp.653-660
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• 2017

본 논문에서는 신호의 고각과 방위각을 추정하기 위한 위상비교 방식의 방향탐지 정확도에 대해 분석하였다. 안테나 4개를 균일 배치한 구조와 3개를 균일 배치한 구조의 고각과 방위각 추정에 대한 분석적 표현을 제시하였고, 방향탐지 오차를 분석하였다. 또한 정확도, 형상, 채널수 관점에서 두 구조를 비교하여 방향탐지 장치 설계에 대한 방향을 제시하였다. 방향탐지 분석결과는 시뮬레이션 결과와 유사한 분포를 나타내고, $1.2^{\circ}RMS$ 이내의 차이를 갖는 것을 확인하였다. 분석 결과로부터 SNR 20 dB, 베이스라인 길이가 반파장일 때, 안테나 4개를 균일 배치한 구조의 경우, 안테나 3개를 배치한 구조에 비해 고각 방향탐지 정확도는 1.15 배 높으며, 방위각 방향탐지 정확도는 서로 동일함을 확인하였다. 또한 2차원 방향탐지 구조는 1차원 방향탐지 구조에서 발생하는 코닝에러가 제거되는 것을 확인하였다.

• 대한인간공학회지
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• 제24권2호
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• pp.45-49
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• 2005

The FSA(Force Sensitive Application) system measures hand force by using force resistance sensors. Compared to conventional hand force measurement systems such as Lafayette hand dynamometer and Jamar hydraulic hand dynamometer, the FSA system can be applied to analyze use of hand forces while the hand is manipulating objects for a task, However, the measurement performance of the FSA system has not been objectively evaluated. The present study tested the FSA system in terms of stability, repeatability, accuracy, and linearity. It is shown that the FSA system has good stability (CV$\leq$0.02) and linearity($R^2$=0.82), but has low repeatability(CV=$0.11{\sim}0.19$) and accuracy(22% of underevaluation on average). This performance result indicates that measurements from the FSA system should be used for relative comparison rather than for absolute comparison.

• 한국군사과학기술학회지
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• 제8권4호
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• pp.5-13
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• 2005

The impact of a long-rod penetrator into oblique plates with combined obliquity and yaw is investigated. The study was done using a newly developed three dimensional dynamic and impact analysis code, which uses the explicit finite element method. Through the comparison of simulation result with experimental result and other code's result, the adaptability and accuracy of the developed code is evaluated under the complex situation in which yaw angle and oblique angle exist simultaneously. As a result of comparison, it has found that deformed shape, residual length and velocity, rotational velocity of long-rod show good agreement with experimental data. Through this study, the applicability and accuracy of the code as a metallic armour system design tool is verified.

• Communications for Statistical Applications and Methods
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• 제18권2호
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• pp.237-244
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• 2011

In call forecasting literature, both the seasonal autoregressive integrated moving average(ARIMA) type models and seasonal linear models have been popularly suggested as competing models. However, their parallel comparison for the forecasting accuracy was not strictly investigated before. This study evaluates the accuracy of both the seasonal linear models and the seasonal ARIMA-type models when predicting intra-day call arrival rates using both real and simulated data. The seasonal linear models outperform the seasonal ARIMA-type models in both one-day-ahead and one-week-ahead call forecasting in our empirical study.

• Geomechanics and Engineering
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• 제8권2호
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• pp.133-152
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• 2015

Mathematical model has been developed for determination of temperature field in multilayer pavement and subgrade, which considers transfer of heat by conduction and convection, receiving of heat from total solar radiation and atmosphere emission, output of heat due to the emission from the surface of pavement. The developed model has been realized by the finite element method for two dimensional problem using two dimensional second order finite element. Calculations for temperature field have been made with the programme realized on the standard mathematical package MATLAB. Accuracy of the developed model has been evaluated by comparison of temperatures, obtained theoretically and experimentally. The results of comparison showed high accuracy of the model. Long-term calculation (within three months) has been made in pavement points in accordance with the data of meteorological station for air temperature. Some regularities have been determined for variation of temperature field.

• International journal of advanced smart convergence
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• 제11권2호
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• pp.185-193
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• 2022

There have been various studies in Korea to develop a %IMF(Intramuscular Fat Percentage) estimation method suitable for Hanwoo. Recently, a %IMF estimation method using a convolutional neural network (CNN), a kind of deep learning method among artificial intelligence methods, has been studied. In this study, we performed a performance comparison when various preprocessing methods were applied to the %IMF estimation of ultrasound images using CNN as mentioned above. The preprocessing methods used in this study are normalization, histogram equalization, edge enhancement, and a method combining normalization and edge enhancement. When estimating the %IMF of Hanwoo by the conventional method that did not apply preprocessing in the experiment, the accuracy was 98.2%. The other hand, we found that the accuracy improved to 99.5% when using preprocessing with histogram equalization alone or combined regularization and edge enhancement.

• Wind and Structures
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• 제36권1호
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• pp.15-29
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• 2023

To better estimate the non-Gaussian extreme wind pressures for high-rise buildings, a data-driven revised Hermitetype peak factor estimation model is proposed in this papar. Subsequently, a comparative study on three types of methods, such as Hermite-type models, short-time estimate Gumbel method (STE), and new translated-peak-process method (TPP) is carried out. The investigations show that the proposed Hermite-type peak factor has better accuracy and applicability than the other Hermite-type models, and its absolute accuracy is slightly inferior to the STE and new TPP methods for non-Gaussian wind pressures by comparing with the observed values. Moreover, these methods generally overestimate the Gaussian wind pressures especially the STE.

• 감성과학
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• 제16권1호
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• pp.95-106
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• 2013

본 연구에서는 자발적인 웃음과 인위적인 웃음을 변별하는 데 있어서 일반 사람들의 정확도와 컴퓨터를 이용한 분류 알고리즘의 정확도를 비교하였다. 실험참가자들은 단일 영상 판단 과제와 쌍비교 판단과제를 수행하였다. 단일 영상판단 과제는 웃음 영상을 한 장씩 제시하면서 이 영상의 웃음이 자발적인 것인지 인위적인 것인지를 판단하는 것이었으며, 쌍비교 판단과제는 동일한 사람에게서 얻은 두 종류의 웃음 영상을 동시에 제시하면서 자발적인 웃음 영상이 어떤 것인지 판단하는 것이었다. 분류 알고리즘의 정확도를 산출하기 위하여 웃음 영상 각각에서 8 종류의 얼굴 특성치들을 추출하였다. 약 50%의 영상을 사용하여 단계적 선형판별분석을 수행하였으며, 여기서 산출된 판별함수를 이용하여 나머지 영상을 분류하였다. 단일 영상에 대한 판단결과, 단계적 선형판별분석의 정확도가 사람들의 정확도보다 높았다. 쌍비교에 대한 판단결과도 단계적 선형판별분석의 정확도가 사람들의 정확도보다 높았다. 20명의 실험참가자 중 선형판별분석의 정확도를 넘어서는 사람은 없었다. 판별분석에 중요하게 사용된 얼굴 특성치는 눈머리의 각도로, 눈을 가늘게 뜬 정도를 나타낸다. Ekman의 FACS에 따르면, 이 특성치는 AU 6에 해당한다. 사람들의 정확도가 낮은 이유는 두 종류의 웃음을 구별할 때, 눈에 관한 정보를 충분히 사용하지 않았기 때문으로 추론되었다.

• Wind and Structures
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• 제5권2_3_4호
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• pp.227-244
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• 2002

Recently, the prediction of wind environment around a building using Computational Fluid Dynamics (CFD) technique comes to be carried out at the practical design stage. However, there have been very few studies which examined the accuracy of CFD prediction of flow around a high-rise building including the velocity distribution at pedestrian level. The working group for CFD prediction of wind environment around building, which consists of researchers from several universities and private companies, was organized in the Architectural Institute of Japan (AIJ) considering such a background. At the first stage of the project, the working group planned to carry out the cross comparison of CFD results of flow around a high rise building by various numerical methods, in order to clarify the major factors which affect prediction accuracy. This paper presents the results of this comparison.

• 한국전자파학회논문지
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• 제23권10호
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• pp.1212-1215
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• 2012

레이다 간섭계에서 표적의 공간 도달 각도를 추정하는 방법 중에서 위상 비교 모노 펄스 알고리즘의 추정 각도 정확도를 향상시키기 위한 위상평균법 및 시간 지연 보상 방안을 제안하였다. 실시간 신호처리 시스템에 적용할 경우, 저역 통과 필터의 특성을 갖는 위상평균법을 적용하면 필연적으로 시간 지연이 발생한다. 이 문제점을 보완하기 위해 곡선 맞춤법을 이용하여 추정된 각도의 변화율을 계산하고 보상하여 실시간 신호처리 시스템에 적용 가능하도록 하였다. 제안 방법의 효용성을 입증하기 위해 실제 레이다 간섭계를 이용하여 획득된 데이터에 적용하여 추정된 각도의 정확도를 비교하였다.