• 한국정밀공학회지
• /
• 제12권6호
• /
• pp.96-104
• /
• 1995

A study for a lathe to machine workpiece with noncircular cross-section is presented. The noncircular cutting is accomplished by controlling radial tool position synchronized with revolution angle of the spindle according to the desired cross-sectional shape. A learning control algorithm is suggested for the tool positioning. The learning law of the algorithm is based on pole-zero cancellation, which guarantees the control stability. The control performances are analyzed and simulated on a numerical computer that the effectiveness of the control algorithm is convinced. The algorithm is tested on a conventional NC-lathe which shows some successful results.

• Journal of Korean Neurosurgical Society
• /
• 제66권1호
• /
• pp.53-62
• /
• 2023

Objective : Deep learning is a machine learning approach based on artificial neural network training, and object detection algorithm using deep learning is used as the most powerful tool in image analysis. We analyzed and evaluated the diagnostic performance of a deep learning algorithm to identify skull fractures in plain radiographic images and investigated its clinical applicability. Methods : A total of 2026 plain radiographic images of the skull (fracture, 991; normal, 1035) were obtained from 741 patients. The RetinaNet architecture was used as a deep learning model. Precision, recall, and average precision were measured to evaluate the deep learning algorithm's diagnostic performance. Results : In ResNet-152, the average precision for intersection over union (IOU) 0.1, 0.3, and 0.5, were 0.7240, 0.6698, and 0.3687, respectively. When the intersection over union (IOU) and confidence threshold were 0.1, the precision was 0.7292, and the recall was 0.7650. When the IOU threshold was 0.1, and the confidence threshold was 0.6, the true and false rates were 82.9% and 17.1%, respectively. There were significant differences in the true/false and false-positive/false-negative ratios between the anterior-posterior, towne, and both lateral views (p=0.032 and p=0.003). Objects detected in false positives had vascular grooves and suture lines. In false negatives, the detection performance of the diastatic fractures, fractures crossing the suture line, and fractures around the vascular grooves and orbit was poor. Conclusion : The object detection algorithm applied with deep learning is expected to be a valuable tool in diagnosing skull fractures.

• Journal of Korea Artificial Intelligence Association
• /
• 제1권1호
• /
• pp.11-16
• /
• 2023

Accurate hospital case modeling and prediction are crucial for efficient healthcare. In this study, we demonstrate the implementation of regression analysis methods in machine learning systems utilizing mathematical statics and machine learning techniques. The developed machine learning model includes Bayesian linear, artificial neural network, decision tree, decision forest, and linear regression analysis models. Through the application of these algorithms, corresponding regression models were constructed and analyzed. The results suggest the potential of leveraging machine learning systems for medical research. The experiment aimed to create an Azure Machine Learning Studio tool for the speedy evaluation of multiple regression models. The tool faciliates the comparision of 5 types of regression models in a unified experiment and presents assessment results with performance metrics. Evaluation of regression machine learning models highlighted the advantages of boosted decision tree regression, and decision forest regression in hospital case prediction. These findings could lay the groundwork for the deliberate development of new directions in medical data processing and decision making. Furthermore, potential avenues for future research may include exploring methods such as clustering, classification, and anomaly detection in healthcare systems.

• 정보교육학회논문지
• /
• 제11권2호
• /
• pp.231-241
• /
• 2007

본 연구는 창의적 문제해결 능력 향상을 위한 알고리즘 학습도구로서 로봇을 이용한 프로그래밍 학습방법을 제안하는데 목적이 있다. 이를 위해 30차시 분량의 로봇 프로그래밍 교육과정과 교재를 개발하였으며, 초등학생 6학년을 대상으로 30차시를 학습시킨 후 평가하였다. 각 차시별 학습결과 산출물 중심으로 성취수준을 평가한 결과, 학습자들이 교육과정 내용을 대부분 이해한 수준으로 분석되었다. 이러한 결과는 개발한 교육과정과 교재가 초등학생들에게 충분히 공감하고 실천 가능하도록 구성되었다고 판단된다. 본 연구에서의 실행 경험을 통해 초등학교에서 로봇 프로그램 학습이 창의적 알고리즘 학습도구로 성공할 수 있는 가능성을 확인하게 되었다.

• 소음진동
• /
• 제10권2호
• /
• pp.331-337
• /
• 2000

The necessity of diagnosis of the rotating machinery which is widely used in the industry is increasing. Many research has been conducted to manipulate field vibration signal data for diagnosing the fault of designated machinery. As the pattern recognition tool of that signal, neural network which use usually back-propagation algorithm was used in the diagnosis of rotating machinery. In this paper, self-organizing feature map(SOFM) which is unsupervised learning algorithm is used in the abnormal defect diagnosis of rotating machinery and then learning vector quantization(LVQ) which is supervised learning algorithm is used to improve the quality of the classifier decision regions.

• Journal of Korean Medical Science
• /
• 제33권43호
• /
• pp.239.1-239.12
• /
• 2018

Background: We described a novel multi-step retinal fundus image reading system for providing high-quality large data for machine learning algorithms, and assessed the grader variability in the large-scale dataset generated with this system. Methods: A 5-step retinal fundus image reading tool was developed that rates image quality, presence of abnormality, findings with location information, diagnoses, and clinical significance. Each image was evaluated by 3 different graders. Agreements among graders for each decision were evaluated. Results: The 234,242 readings of 79,458 images were collected from 55 licensed ophthalmologists during 6 months. The 34,364 images were graded as abnormal by at-least one rater. Of these, all three raters agreed in 46.6% in abnormality, while 69.9% of the images were rated as abnormal by two or more raters. Agreement rate of at-least two raters on a certain finding was 26.7%-65.2%, and complete agreement rate of all-three raters was 5.7%-43.3%. As for diagnoses, agreement of at-least two raters was 35.6%-65.6%, and complete agreement rate was 11.0%-40.0%. Agreement of findings and diagnoses were higher when restricted to images with prior complete agreement on abnormality. Retinal/glaucoma specialists showed higher agreements on findings and diagnoses of their corresponding subspecialties. Conclusion: This novel reading tool for retinal fundus images generated a large-scale dataset with high level of information, which can be utilized in future development of machine learning-based algorithms for automated identification of abnormal conditions and clinical decision supporting system. These results emphasize the importance of addressing grader variability in algorithm developments.

• 경영과학
• /
• 제18권2호
• /
• pp.25-38
• /
• 2001

The well-known back-propagation algorithm for multi-layered neural network has successfully been applied to pattern c1assification problems with remarkable flexibility. Recently. the multi-layered neural network is used as a powerful data mining tool. Nevertheless, in many cases with complex boundary of classification, the successful learning is not guaranteed and the problems of long learning time and local minimum attraction restrict the field application. In this paper, an Improved learning procedure of multi-layered neural network is proposed. The procedure is based on the generalized delta rule but it is particular in the point that the architecture of network is not fixed but enlarged during learning. That is, the number of hidden nodes or hidden layers are increased to help finding the classification boundary and such procedure is controlled by entropy evaluation. The learning speed and the pattern classification performance are analyzed and compared with the back-propagation algorithm.

• 컴퓨터교육학회논문지
• /
• 제12권1호
• /
• pp.33-44
• /
• 2009

본 연구에서는 중학생의 알고리즘 학습을 효과적으로 지원하기 위한 도구로 교육용 로봇을 선택하고 로봇의 활용 효과를 최대화하기 위한 교수 학습 프로그램을 개발하였다. 해당 프로그램은 알고리즘 학습에 대한 내적 동기 유발 및 창의적 문제해결력 향상을 위한 교수 학습 전략을 반영하여 구성하였으며, 중학교 학습자의 인지적 발달 특성과 알고리즘 학습을 처음 접하는 초보 학습자라는 특성을 반영하였다. 개발한 프로그램을 실제 중학교 학습자들에게 적용한 결과, 로봇 활용 알고리즘 학습을 수행한 집단이 일반 프로그래밍 언어를 활용한 알고리즘 학습을 수행한 집단에 비해 내적 동기와 창의적 문제해결성향이 유의하게 높게 나타났음을 확인하였다. 이러한 연구 결과는 향후 새로운 교육과정이 시행될 경우, 중학생의 알고리즘 학습을 위한 교수 학습 도구의 선정 및 교수 학습 설계에 유용한 방향을 제공해 줄 수 있을 것이다.

• 한국융합학회논문지
• /
• 제10권2호
• /
• pp.13-20
• /
• 2019

맞춤형 교육을 위해 학습자에 맞는 학습 경로를 탐색하는 것은 필수적이다. 유전 알고리즘은 해공간이 매우 커서 결정적 방법으로 해를 구하기 어려울 때 타당한 시간 내에 최적해를 찾게 해준다. 본 연구는 유전 알고리즘을 이용하여 200개 코드를 가진 악보 27개를 대상으로 학습자 부담을 최소화하고 단계별 학습량을 균등하게 분산함으로써 학습 효과를 최대화 할 수 있도록 학습 경로를 최적화하였다. 학습 컨텐츠가 27개만 되어도 학습 경로의 순열 크기는 $10^{28}$을 넘지만, 본 연구에서 구현한 도구로 평균 20분 이내에 최적해를 구할 수 있었다. 실험 결과는 유전 알고리즘이 다양한 목적의 맞춤형 교육을 위한 복잡한 학습 경로 설계에 효과적임을 보여주었다. 제안한 방법은 다른 교육 도메인에도 활용할 수 있을 것으로 기대된다.

• Geomechanics and Engineering
• /
• 제37권3호
• /
• pp.263-277
• /
• 2024

Artificial Neural Networks (ANNs) are artificial learning algorithms that provide successful results in solving many machine learning problems such as classification, prediction, object detection, object segmentation, image and video classification. There is an increasing number of studies that use ANNs as a prediction tool in soil classification. The aim of this research was to understand the role of hyperparameter optimization in enhancing the accuracy of ANNs for soil type classification. The research results has shown that the hyperparameter optimization and hyperparamter optimized ANNs can be utilized as an efficient mechanism for increasing the estimation accuracy for this problem. It is observed that the developed hyperparameter tool (HyperNetExplorer) that is utilizing the Covariance Matrix Adaptation Evolution Strategy (CMAES), Genetic Algorithm (GA) and Jaya Algorithm (JA) optimization techniques can be successfully used for the discovery of hyperparameter optimized ANNs, which can accomplish soil classification with 100% accuracy.