• International Journal of Precision Engineering and Manufacturing
• /
• 제3권1호
• /
• pp.33-42
• /
• 2002

Recently, various experiments to apply reinforcement learning method to the self-learning intelligent control of continuous dynamic system have been reported in the machine learning related research community. The reports have produced mixed results of some successes and some failures, and show that the success of reinforcement learning method in application to the intelligent control of continuous control systems depends on the ability to combine proper function approximation method with temporal difference methods such as Q-learning and value iteration. One of the difficulties in using function approximation method in connection with temporal difference method is the absence of guarantee for the convergence of the algorithm. This paper provides a proof of convergence of a particular function approximation method based on \"barycentric interpolator\" which is known to be computationally more efficient than multilinear interpolation .

• 융합신호처리학회 학술대회논문집
• /
• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
• /
• pp.217-220
• /
• 2001

본 논문에서는 시공간정보를 이용하여 연속된 영상에서 움직이는 물체를 분할하는 방법을 제안한다. 제안 된 방법은 차영상(difference Image)을 이용한 움직임 추출단계, k-means 클러스터링 알고리즘을 이용한 영역 분할단계, 그리고 영역의 밝기값과 움직임 정보를 움직임 추정 및 분할단계로 구-성되어져 있다. 제안된 방법을 실험해본 결과 연속영상 내에서 다양한 움직임을 가진 물체를 효과적으로 분할 할 수 있는 결과를 얻을 수 있다.

• 산업경영시스템학회지
• /
• 제34권4호
• /
• pp.189-196
• /
• 2011

In this paper, we propose a logical control-based actor-critic algorithm as an efficient approach for the approximation of the capacitated fab scheduling problem. We apply the average reward temporal-difference learning method for estimating the relative value functions of system states, while avoiding deadlock situation by Banker's algorithm. We consider the Intel mini-fab re-entrant line for the evaluation of the suggested algorithm and perform a numerical experiment by generating some sample system configurations randomly. We show that the suggested method has a prominent performance compared to other well-known heuristics.

• 한국언어정보학회지:언어와정보
• /
• 제8권1호
• /
• pp.137-161
• /
• 2004

In this paper, I will look at two conditional connectives in Korean and point out differences between -(u)myen and -ta/la-myen in their distributions and semantics. One of the differences is that -ta/la-myen always allows epistemic interpretation, whereas -(u)myen allows epistemic interpretation only when the event time of the antecedent clause is in the past or present. A second difference is that only -(u)myen is used in purely temporal and habitual conditionals. A third difference is that the modality marker -keyss, which can have volitional or predictive interpretation with -(u)myen, cannot have predictive interpretation with -ta/la-myen. I propose that -ta/la-myen has the operator of settledness, which is defined with respect to the speech time, and explain the differences listed based on the semantics of settledness.

• Journal of applied mathematics & informatics
• /
• 제39권5_6호
• /
• pp.623-641
• /
• 2021

In this paper, numerical treatment of singularly perturbed parabolic delay differential equations is considered. The considered problem have small delay on the spatial variable of the reaction term. To treat the delay term, Taylor series approximation is applied. The resulting singularly perturbed parabolic PDEs is solved using Crank Nicolson method in temporal direction with non-standard finite difference method in spatial direction. A detail stability and convergence analysis of the scheme is given. We proved the uniform convergence of the scheme with order of convergence O(N^-1 + (∆t)²), where N is the number of mesh points in spatial discretization and ∆t is mesh length in temporal discretization. Two test examples are used to validate the theoretical results of the scheme.

• 대한원격탐사학회지
• /
• 제35권6_3호
• /
• pp.1209-1219
• /
• 2019

지속적인 식생 모니터링을 위해서는 다중 위성자료의 시간 및 공간해상도의 상호 보완적 특성을 융합한 높은 시공간해상도에서의 식생지수 생성이 필요하다. 이 연구에서는 식생 모니터링에서 다중 위성자료의 시공간 융합 모델에 따른 시계열 변화 정보의 예측 정확도를 정성적, 정량적으로 분석하였다. 융합 모델로는 식생 모니터링 연구에 많이 적용되었던 Spatial and Temporal Adaptive Reflectance Fusion Model(STARFM)과 Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model(ESTARFM)을 비교하였다. 예측 정확도의 정량적 평가를 위해 시간해상도가 높은 MODIS 자료를 이용해 모의자료를 생성하고, 이를 입력자료로 사용하였다. 실험 결과, ESTARFM에서 시계열 변화 정보에 대한 예측 정확성이 STARFM보다 높은 것으로 나타났다. 그러나 예측시기와 다중 위성자료의 동시 획득시기의 차이가 커질수록 STARFM과 ESTARFM 모두 예측 정확성이 저하되었다. 이러한 결과는 예측 정확성을 향상시키기 위해서는 예측시기와 가까운 시기의 다중 위성자료를 이용해야 함을 의미한다. 광학영상의 제한적 이용을 고려한다면, 식생 모니터링을 위해 이 연구의 제안점을 반영한 개선된 시공간 융합 모델 개발이 필요하다.

• 대한물리의학회지
• /
• 제5권3호
• /
• pp.385-394
• /
• 2010

Purpose : The present study was to examine the difference and severity of asymmetry in independently ambulating stroke survivors and to establish the association between gait asymmetry, velocity, and the motor function of lower extremity. Methods : The subjects used in this study were 43 subjects with hemiparesis being able to walk independently. Motor function of lower extremity was measured clinically with the Fugl Meyer-Lower /Extremity Assessment. Overground gait velocity and spatia-temporal parameters were collected by the GAITRite system. Results : Thirty(69.77%) patients showed statistically significant temporal asymmetry while 28(65.1%) exhibited statistically significant spatial asymmetry. One-way ANOVA results showed a main effect of temporal asymmetry group(normative, mild, severe) for gait velocity(F=74.129), FM-L/E(F=17.270), swing-stance symmetry(F=66.869, F=13.485, respectively), spatio-temporal asymmetry(F=13.166, F=31.800, respectively) 66, F=31.800, respectively). Gait velocity was negatively associated with temporal asymmetry(r=-.83), spatial asymmetry(r=-.60). Motor function of lower extremity was also associated with temporal asymmetry(r=-.58), and spatial asymmetry(r=-.50). Conclusion : The study attempted to establish the standard assessment of hemiparesis gait symmetry in light of the complex relationship with motor impairment and gait velocity. More future work will need to link the degree of gait asymmetry to clinically relevant outcomes to better establish the clinical significance of such observations.

• 한국정밀공학회지
• /
• 제24권1호
• /
• pp.101-109
• /
• 2007

In situations of spatio-temporal perception about visuo-auditory stimulus, researches propose optimal integration hypothesis that perceptual process is optimized to the interaction of the senses for the precision of perception. So, when the visual information considered generally dominant over any other sense is ambiguous, the information of the other sense like auditory stimulus influences the perceptual process in interaction with visual information. Thus, we performed two different experiments to certain the conditions of the interacting senses and influence of the condition. We consider the interaction of the visuo-auditory stimulation in the free space, the color of visual stimulus and sex difference of testee with normal people. In first experiment, 12 participants were asked to judge the change in the frequency of audio-visual stimulation using a visual flicker and auditory flutter stimulation in the free space. When auditory temporal cues were presented, the change in the frequency of the visual stimulation was associated with a perceived change in the frequency of the auditory stimulation as the results of the previous studies using headphone. In second experiment, 30 male and 30 female were asked to judge the change in the frequency of audio-visual stimulation using a color of visual flicker and auditory flutter stimulation. In the color condition using red and green. Both male and female testees showed same perceptual tendency. male and female testees showed same perceptual tendency however, in case of female, the standard deviation is larger than that of male. This results implies that audio-visual asymmetry effects are influenced by the cues of visual and auditory information, such as the orientation between auditory and visual stimulus, the color of visual stimulus.

• 임상간호연구
• /
• 제24권2호
• /
• pp.227-234
• /
• 2018

Purpose: This study compared the temporal artery temperature (TAT) measured by infrared temporal artery thermometers to the axillary temperature (AT) measured by standard mercury-in-glass thermometers, and evaluated accuracy of the TAT measurement for clinical practice. Methods: A total of 247 adult inpatients in general wards in a tertiary medical center located in Seoul participated in the study. The TAT was measured within one minute after the AT measurement. Data were analyzed using descriptive statistics, paired t-test, Pearson correlation coefficient, linear regression, and the Bland-Altman plot. Results: There was a significant difference in mean temperature between AT and TAT, $36.89^{\circ}C$ (SD=0.70) versus $37.35^{\circ}C$ (SD=0.72). The Bland-Altman plots demonstrated the difference between the AT and TAT as -1.29 to +0.33. The specificity and sensitivity of the TAT in detecting fever were high. The positive predictive values were 57.5% and 71.0% when the AT were higher than $38.0^{\circ}C$ and the TAT fever cutoff levels were $38.0^{\circ}C$ and $38.3^{\circ}C$ respectively. Conclusion: TAT and AT were highly correlated and agreeable, indicating that TAT is as accurate as AT. The findings suggested that TAT measurement can be used in clinical practice. For accurate communication between medical personnel, medical institutions need to provide guidelines for temperature measurement, especially for the use of thermometer and measurement sites.

• 대한원격탐사학회지
• /
• 제36권5_1호
• /
• pp.807-821
• /
• 2020

이 연구에서는 작물 모니터링을 위한 시계열 고해상도 영상 구축을 위해 기존 중저해상도 위성영상의 융합을 위해 개발된 대표적인 시공간 융합 모델의 적용성을 평가하였다. 특히 시공간 융합 모델의 원리를 고려하여 입력 영상 pair의 특성 차이에 따른 모델의 예측 성능을 비교하였다. 농경지에서 획득된 시계열 Sentinel-2 영상과 RapidEye 영상의 시공간 융합 실험을 통해 시공간 융합 모델의 예측 성능을 평가하였다. 시공간 융합 모델로는 Spatial and Temporal Adaptive Reflectance Fusion Model(STARFM), SParse-representation-based SpatioTemporal reflectance Fusion Model(SPSTFM)과 Flexible Spatiotemporal DAta Fusion(FSDAF) 모델을 적용하였다. 실험 결과, 세 시공간 융합 모델은 예측 오차와 공간 유사도 측면에서 서로 다른 예측 결과를 생성하였다. 그러나 모델 종류와 관계없이, 예측 시기와 영상 pair가 획득된 시기 사이의 시간 차이보다는 예측 시기의 저해상도 영상과 영상 pair의 상관성이 예측 능력 향상에 더 중요한 것으로 나타났다. 또한 작물 모니터링을 위해서는 오차 전파 문제를 완화할 수 있는 식생지수를 시공간 융합의 입력 자료로 사용해야 함을 확인하였다. 이러한 실험 결과는 작물 모니터링을 위한 시공간 융합에서 최적의 영상 pair 및 입력 자료 유형의 선택과 개선된 모델 개발의 기초정보로 활용될 수 있을 것으로 기대된다.