• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.5
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• pp.685-690
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• 2021

In this paper, we propose a deep learning-based transmit power control scheme to maximize the sum-rates while satisfying the minimum data-rate in downlink non-orthogonal multiple access (NOMA) systems. In downlink NOMA, we consider the co-channel interference that occurs from a base station other than the cell where the user is located, and the user feeds back the signal-to-interference plus noise power ratio (SINR) information instead of channel state information to reduce system feedback overhead. Therefore, the base station controls transmit power using only SINR information. The use of implicit SINR information has the advantage of decreasing the information dimension, but has disadvantage of reducing the data-rate. In this paper, we resolve this problem with deep learning-based training methods and show that the performance of training can be improved if the dimension of deep learning inputs is effectively reduced. Through simulation, we verify that the proposed deep learning-based power control scheme improves the sum-rate while satisfying the minimum data-rate.

• Journal of the Korea Society of Computer and Information
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• v.27 no.5
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• pp.37-45
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• 2022

As of 2020, about 500 hours of videos are uploaded to YouTube, a representative online video platform, per minute. As the number of users acquiring information through various uploaded videos is increasing, online video platforms are making efforts to provide better recommendation services. The currently used recommendation service recommends videos to users based on the user's viewing history, which is not a good way to recommend videos that deal with specific purposes and interests, such as educational videos. The recent recommendation system utilizes not only the user's viewing history but also the content features of the item. In this paper, we extract the content features of educational video for educational video recommendation based on YouTube, design a recommendation system using it, and implement it as a web application. By examining the satisfaction of users, recommendataion performance and convenience performance are shown as 85.36% and 87.80%.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.189-201
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• 2011

In this paper, we design an ontology which provides interoperability by integrating typical metadata specifications and defines concepts and semantic relations between concepts that are used to describe metadata for learning objects in university courses. And we organize a hierarchical structured e-Learning system for efficient retrieval of learning objects on many local storages that use different specifications to describe metadata and propose a query processing method based on inferences. The proposed e-Learning system can provide more accurate and satisfactory retrieval service by using the designed ontology because both learning objects that be directly connected to user queries and deduced learning objects that be semantically connected to them are retrieved.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.522-534
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• 2019

The purpose of this study is to investigate the interaction factors(learning motivation, concrete feedback, learner's control) and affordance factors (aesthetics, playfulness, stability) that influence flow in e - learning. This study collected 236 survey data from e-learning users. The data was analyzed the statistical relationships among the variables using the SPSS21 and AMOS21. The measurement model was reliable and valid, and the structual model was good. The result shows that interaction factors (concrete feedback, learner's control) and affordance factor (playfulness) influence on flow. Flow has a significant effect on satisfaction. Especially the effect of playfulness on flow is meaningful. Playfulness is one of the most important factors leading to the flow state of humans. The contribution of this study is to find the factors influencing flow in the interaction between learners and computer in e-learning. It can be used to provide an entertainment experience that can enhance the satisfaction of consumers in the Internet environment by finding the antecedents that affect the flow in computer - human interaction.

• Annual Conference of KIPS
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• 2009.11a
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• pp.847-848
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• 2009

다양한 정보의 흐름과 함께 빠르게 변화해가는 웹 환경에서 사용자들의 다양한 요구 사항을 만족시키기 위해서는 이러닝 시스템 또한 그에 발맞추어 빠르고 유연한 기능 확장이 필요하다. 하지만 기존의 웹 어플리케이션 구현 방식은 이에 대한 해답이 되지 못한다. 본 논문에서는 이러한 문제를 해결하기 서비스 기반 구조 기법을 사용하여 다양한 사용자 요구사항을 쉽게 서비스 할 수 있는 LMS 모델을 설계 및 구현하였다.

• Journal of the Korea Convergence Society
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• v.10 no.6
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• pp.235-242
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• 2019

Recently, the use of artificial intelligence technology including deep learning has become active in various fields. In particular, several algorithms showing superior performance in object recognition and detection based on deep learning technology have been presented. In this paper, we propose the proper direction for the implementation of mobile healthcare application that user's convenience is effectively reflected. By effectively analyzing the current state of use satisfaction research for the existing fitness applications and the current status of mobile healthcare applications, we attempt to secure survival and superiority in the fitness application market, and, at the same time, to maintain and expand the existing user base.

• Information Systems Review
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• v.23 no.3
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• pp.51-75
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• 2021

Global e-commerce websites offer personalized recommendation services to gain sustainable competitiveness. Existing studies have offered personalized recommendation services using quantitative preferences such as ratings. However, offering personalized recommendation services using only quantitative data has raised the problem of decreasing recommendation performance. For example, a user gave a five-star rating but wrote a review that the user was unsatisfied with hotel service and cleanliness. In such cases, has problems where quantitative and qualitative preferences are inconsistent. Recently, a growing number of studies have considered review data simultaneously to improve the limitations of existing personalized recommendation service studies. Therefore, in this study, we identify review and rating mismatches and build a new user profile to offer personalized recommendation services. To this end, we use deep learning algorithms such as CNN, LSTM, CNN + LSTM, which have been widely used in sentiment analysis studies. And extract sentiment features from reviews and compare with quantitative preferences. To evaluate the performance of the proposed methodology in this study, we collect user preference information using real-world hotel data from the world's largest travel platform TripAdvisor. Experiments show that the proposed methodology in this study outperforms the existing other methodologies, using only existing quantitative preferences.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.41-41
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• 2018

하천과 저수지의 수질을 예측하고 관리하는데 수리 수질예측모형이 널리 활용되고 있다. 수질예측모형은 유역이나 수체 내의 오염물질 이동경로나 농도를 수치해석 방법으로 계산하여 사용자가 필요로 하는 지점과 시점에서의 수질자료 생산하는데 활용되고 있다. 수질예측모형은 검 보정을 통해 정확도를 확보하며, 정확도의 확보를 위해서는 높은 수준의 전문성을 필요로 한다. 특히 시행착오법으로 모형을 보정하는 경우 많은 시간과 노력을 필요로 하게 되며, 보정계수를 과대 혹은 과소로 모형에 적용하는 오류를 범하기 쉽고 모델러의 주관이 관여되기 쉽다. 그래서 본 연구에서는 CE-QUAL-W2모형의 조류항목에 대한 모형 보정을 위하여 Chl-a와 남조류세포수에서 주로 활용되고 있는 보정계수에 대한 민감도 분석 결과를 토대로 매개변수별 모의결과 변화율을 산정하였으며, 시기적 경향성을 재현하기 위해 Ensemble-Bagging 기법과 머신 러닝 기법을 적용하여 모형 구동횟수를 최소화 할 수 있는 방법으로 구성하였다. Chl-a를 보정하기 위한 매개변수는 9개를 선정하였으며, 규조류, 남조류, 녹조류에 총 27개 매개 변수를 민감도 분석으로 도출 한 후 예상 변화율 대비 이벤트별 모의치와 실측치 간 %difference가 유사하도록 매개변수를 조정하였다. 또한 각 이벤트 조합의 매개변수 빈도수와 매개변수별 예상변화율, 시기적 조류특성을 고려하여 가중치를 도출하였으며, 1회 보정에 맞춰 Chl-a 모델 실행결과를 %difference로 평가한 후 "good"등급을 만족할 때까지 반복 적용하였다. 남조류세포수의 경우 Chl-a에 맞춰 매개변수 최적화 이후 남조류세포수 농도를 세포수로 환산하기 위한 CACEL에 대해 머신러닝 기법을 적용하였으며, CACEL 추정변화율 회귀식에 따라 평가 한 후 %difference "good"등급 이상을 만족할 때까지 반복 수행하는 방법을 적용하였다. 본 연구에서는 수질예측모형의 정확도를 확보하기 위하여 최적화 기법을 적용하였으며, 이를 통해 모형을 보정하는 과정에서 요구되는 시간과 노력을 줄일 수 있도록 하였으며, Ensemble기법과 머신러닝 기법을 적용하여 모형보정계수 적용에 객관성을 확보할 수 있도록 하였다.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.403-404
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• 2019

동남아의 저렴한 물가, 비행의 발달 등의 이유로 국내 관광에 대한 관심도가 떨어지면서 국내 관광에 대해 관심은 갖고 있지만, 사용자는 충분히 만족하지 못한다. 본 논문에서는 이를 해결하고자 사람들의 국내 여행에 대한 여행 만족도를 증가시킬 수 있는 방법을 제시한다. 또 비슷한 기술을 가진 다른 기술과 비교해 실제 적용 가능성을 고려하여 여러 기술들과 비교 분석한다.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.203-213
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• 2014

In this study, we proposed a new model with ISOIA (Insect Search by Observation based on Insect Appearance) method based on observation by insect appearance to improve user satisfaction, and compared it with the ISBC and ISOBC methods. In order to test these three insect search systems with AHP method, we derived three evaluation criteria for user satisfaction and three sub-evaluation criteria by evaluation criterion. In the ecological environment, non-experts need insect search systems to identify insect species and to get u-Learning contents related to the insects. To assist the public the non-experts, ISBC (Insect Search by Biological Classification) method based on biological classification to search insects and ISOBC (Insect Search by Observation based on Biological Classification) method based on the inference that identifies the observed insect through observation according to biological classification have been provided. In the test results, we found the order of priorities was ISOIA, ISOBC, and ISBC. It shows that the ISOIA system proposed in this study is superior in usage and quality compared with the previous insect search systems.