• Title/Summary/Keyword: 네트워크 모델링

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Channel Modeling and RF Performance Verification in mmWave Bands Based on NS-3 (NS-3 기반의 mmWave 대역 채널 모델링 및 RF 성능 검증)

  • Seung-Min Lee;Jun-Seok Seo;Hong-Je Jang;Myung-Ryul Choi
    • Journal of IKEEE
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    • v.27 no.4
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    • pp.650-656
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    • 2023
  • This paper implements a channel model for mmWave bands using an NS-3-based 5G system-level simulator and analyzes the reliability and validity of the implemented model through RF performance verification. The channel model for RF performance verification in the mmWave bands consider parameters such as characteristics defined in 3GPP TR 38.901, beam-forming, antenna configuration, scenarios, among others. Furthermore, the simulation results verify compliance within the ranges permitted by the 3GPP standards and verify reliability in indoor environmental scenarios by exploiting the Radio Environment Map (REM). Therefore, the channel model implemented in this study is applicable to the actual design and establishment of 5G networks, presenting a method to evaluate and validate RF performance by adjusting various parameters.

Analyzing Issues on Environment-Friendly Agriculture Using Topic Modeling and Network Analysis (토픽모델링과 네트워크분석을 활용한 친환경농업 이슈분석에 관한 연구)

  • Shin, Ye-Eun;Shin, Eun-Seo;Kim, Sang-Bum;Choi, Jin-Ah;Kim, Myunghyun;Han, Seokjun;An, Kyungjin
    • Journal of Korean Society of Rural Planning
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    • v.29 no.4
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    • pp.35-53
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    • 2023
  • This study attempts to identify the flow of key topics and issues of research trends related to environment-friendly agriculture conducted around the 2000s in South Korea and compare them with the environment-friendly agriculture promotion plan to seek the level of consistency and the direction of future development of environment-friendly agriculture. For the analysis of environment-friendly agriculture research trends and policy consistency, 'topic modeling', which is suitable for subject classification of large amounts of unstructured data, and 'text network analysis', which visualizes the relationship between keywords as a network and interprets its characteristics, were utilized. Overall, active discussions were held on 'technical discussions for the production and cultivation of environment-friendly agricultural products' and 'food safety & consumer awareness', and keywords such as production, cultivation, consumption, and safety were consistently linked to other keywords regardless of time. In addition, it was found that the issue of environment-friendly agriculture was partially consistent with the policy direction of the period. Considering the fact that the ongoing '5th Environment-Friendly Agriculture Promotion Phase' emphasizes the strengthening of rural environment management and aims to ensure the continuous quantitative and qualitative development of environment-friendly agriculture, active discussions and research on its environmental contributions and management methods are needed.

Two-Stage Neural Network Optimization for Robust Solar Photovoltaic Forecasting (강건한 태양광 발전량 예측을 위한 2단계 신경망 최적화)

  • Jinyeong Oh;Dayeong So;Jihoon Moon
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2024.01a
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    • pp.31-34
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    • 2024
  • 태양광 에너지는 탄소 중립 이행을 위한 주요 방안으로 많은 주목을 받고 있다. 태양광 발전량은 여러 환경적 요인에 따라 크게 달라질 수 있으므로, 정확한 발전량 예측은 전력 네트워크의 안정성과 효율적인 에너지 관리에 근본적으로 중요하다. 대표적인 인공지능 기술인 신경망(Neural Network)은 불안정한 환경 변수와 복잡한 상호작용을 효과적으로 학습할 수 있어 태양광 발전량 예측에서 우수한 성능을 도출하였다. 하지만, 신경망은 모델의 구조나 초매개변수(Hyperparameter)를 최적화하는 것은 복잡하고 시간이 많이 드는 작업이므로, 에너지 분야에서 실제 산업 적용에 한계가 존재한다. 본 논문은 2단계 신경망 최적화를 통한 태양광 발전량 예측 기법을 제안한다. 먼저, 태양광 발전량 데이터 셋을 훈련 집합과 평가 집합으로 분할한다. 훈련 집합에서, 각기 다른 은닉층의 개수로 구성된 여러 신경망 모델을 구성하고, 모델별로 Optuna를 적용하여 최적의 초매개변숫값을 선정한다. 다음으로, 은닉층별 최적화된 신경망 모델을 이용해 훈련과 평가 집합에서는 각각 5겹 교차검증을 적용한 발전량 추정값과 예측값을 출력한다. 마지막으로, 스태킹 앙상블 방식을 채택해 기본 초매개변숫값으로 설정해도 우수한 성능을 도출하는 랜덤 포레스트를 이용하여 추정값을 학습하고, 평가 집합의 예측값을 입력으로 받아 최종 태양광 발전량을 예측한다. 인천 지역으로 실험한 결과, 제안한 방식은 모델링이 간편할 뿐만 아니라 여러 신경망 모델보다 우수한 예측 성능을 도출하였으며, 이를 바탕으로 국내 에너지 산업에 이바지할 수 있을 것으로 기대한다.

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Retained Message Delivery Scheme utilizing Reinforcement Learning in MQTT-based IoT Networks (MQTT 기반 IoT 네트워크에서 강화학습을 활용한 Retained 메시지 전송 방법)

  • Yeunwoong Kyung;Tae-Kook Kim;Youngjun Kim
    • Journal of Internet of Things and Convergence
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    • v.10 no.2
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    • pp.131-135
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    • 2024
  • In the MQTT protocol, if the retained flag of a message published by a publisher is set, the message is stored in the broker as a retained message. When a new subscriber performs a subscribe, the broker immediately sends the retained message. This allows the new subscriber to perform updates on the current state via the retained message without waiting for new messages from the publisher. However, sending retained messages can become a traffic overhead if new messages are frequently published by the publisher. This situation could be considered an overhead when new subscribers frequently subscribe. Therefore, in this paper, we propose a retained message delivery scheme by considering the characteristics of the published messages. We model the delivery and waiting actions to new subscribers from the perspective of the broker using reinforcement learning, and determine the optimal policy through Q learning algorithm. Through performance analysis, we confirm that the proposed method shows improved performance compared to existing methods.

A study on research trends for pregnancy in adolescence: Focusing on text network analysis and topic modeling (청소년 임신에 대한 연구 동향 분석: 텍스트 네트워크 분석과 토픽 모델링)

  • Park, Seungmi;Kwak, Eunju;Park, Hye Ok;Hong, Jung Eun
    • The Journal of Korean Academic Society of Nursing Education
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    • v.30 no.2
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    • pp.149-159
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    • 2024
  • Purpose: The aim of this study was to identify core keywords and topic groups in the "adolescent pregnancy" field of research for a better understanding of research trends in the past 10 years. Methods: Topics related to adolescent pregnancy were extracted from 3,819 articles that were published in journals between January 2013 and July 2023. Abstracts were retrieved from five databases (MEDLINE, CINAHL, Embase, RISS, and KISS). Keywords were extracted from the abstracts and cleaned using semantic morphemes. Text network analysis and topic modeling were performed using NetMiner 4.3.3. Results: The most important keywords were "health," "woman," "risk," "group," "girl," "school," "service," "family," "program," and "contraception." Five topic groups were identified through topic modeling. Through the topic modeling analysis, five themes were derived: "health service," "community program for school girls," "risks for adult women," "relationship risks," and "sexual contraceptive knowledge." Conclusion: This study utilized text network analysis and topic modeling to analyze keywords from abstracts of research conducted over the past decade on adolescent pregnancy. Given that adolescent pregnancy leads to physical, mental, social, and economic issues, it is imperative to provide integrated intervention programs, including prenatal/postnatal care, psychological services, proper contraception methods, and sex education, through school and community partnerships, as well as related research studies. Nurses can play a vital role by actively engaging in prevention efforts and directly supporting and educating socially disadvantaged adolescent mothers, which could significantly contribute to improving their quality of life.

A Study on the Security Requirements Analysis to Build a Zero Trust-Based Remote Work Environment (제로트러스트 기반의 원격 근무 환경을 구축하기 위한 보안요구사항 분석 연구)

  • Hae-na Kim;Ye-jun Kim;Seung-joo Kim
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.34 no.1
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    • pp.83-102
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    • 2024
  • Recently, as the use of the cloud increases year by year and remote work within the enterprise has become one of the new types of work, the security of the cloud-based remote work environment has become important. The introduction of zero trust is required due to the limitations of the existing perimeter security model that assumes that everything in the internal network is safe. Accordingly, NIST and DoD published standards related to zero trust architecture, but the security requirements of that standard describe only logical architecture at the abstract level. Therefore, this paper intends to present more detailed security requirements compared to NIST and DoD standards by performing threat modeling for OpenStack clouds. After that, this research team performed a security analysis of commercial cloud services to verify the requirements. As a result of the security analysis, we identified security requirements that each cloud service was not satisfied with. We proposed potential threats and countermeasures for cloud services with zero trust, which aims to help build a secure zero trust-based remote working environment.

A Text Mining Study on Endangered Wildlife Complaints - Discovery of Key Issues through LDA Topic Modeling and Network Analysis - (멸종위기 야생생물 민원 텍스트 마이닝 연구 - LDA 토픽 모델링과 네트워크 분석을 통한 주요 이슈 발굴 -)

  • Kim, Na-Yeong;Nam, Hee-Jung;Park, Yong-Su
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.26 no.6
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    • pp.205-220
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    • 2023
  • This study aimed to analyze the needs and interests of the public on endangered wildlife using complaint big data. We collected 1,203 complaints and their corresponding text data on endangered wildlife, pre-processed them, and constructed a document-term matrix for 1,739 text data. We performed LDA (Latent Dirichlet Allocation) topic modeling and network analysis. The results revealed that the complaints on endangered wildlife peaked in June-August, and the interest shifted from insects to various endangered wildlife in the living area, such as mammals, birds, and amphibians. In addition, the complaints on endangered wildlife could be categorized into 8 topics and 5 clusters, such as discovery report, habitat protection and response request, information inquiry, investigation and action request, and consultation request. The co-occurrence network analysis for each topic showed that the keywords reflecting the call center reporting procedure, such as photo, send, and take, had high centrality in common, and other keywords such as dung beetle, know, absence and think played an important role in the network. Through this analysis, we identified the main keywords and their relationships within each topic and derived the main issues for each topic. This study confirmed the increasing and diversifying public interest and complaints on endangered wildlife and highlighted the need for professional response. We also suggested developing and extending participatory conservation plans that align with the public's preferences and demands. This study demonstrated the feasibility of using complaint big data on endangered wildlife and its implications for policy decision-making and public promotion on endangered wildlife.

Comparison and Analysis for the Topology of Bladeless Wind Power Generator (블레이드리스 풍력발전기의 토폴로지에 관한 비교·분석)

  • Junhyuk Min;Sungin Jeong
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.24 no.4
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    • pp.147-154
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    • 2024
  • This study focuses on the modeling and analysis of the linear generator for a bladeless wind power generation to overcome the limitations and drawbacks of conventional wind turbines. A bladeless wind power generation system has the advantages of low land requirement for installation and maintenance cost compared to a blade wind power turbine. Nevertheless, question concerning the generator topology are not satisfying answered. The goal of the research is to compare and analyze the characteristics of horizontal and vertical structures of linear generator for bladeless wind power systems. The proposed topology will be analyzed using magnetic energy by equivalent magnetic circuit method, and then it has been compared and evaluated by finite element method. The results of this project will give elaborate information about new generator structures for wind power system and provide insights into the characteristics of bladeless wind power generation.

Story-based Information Retrieval (스토리 기반의 정보 검색 연구)

  • You, Eun-Soon;Park, Seung-Bo
    • Journal of Intelligence and Information Systems
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    • v.19 no.4
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    • pp.81-96
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    • 2013
  • Video information retrieval has become a very important issue because of the explosive increase in video data from Web content development. Meanwhile, content-based video analysis using visual features has been the main source for video information retrieval and browsing. Content in video can be represented with content-based analysis techniques, which can extract various features from audio-visual data such as frames, shots, colors, texture, or shape. Moreover, similarity between videos can be measured through content-based analysis. However, a movie that is one of typical types of video data is organized by story as well as audio-visual data. This causes a semantic gap between significant information recognized by people and information resulting from content-based analysis, when content-based video analysis using only audio-visual data of low level is applied to information retrieval of movie. The reason for this semantic gap is that the story line for a movie is high level information, with relationships in the content that changes as the movie progresses. Information retrieval related to the story line of a movie cannot be executed by only content-based analysis techniques. A formal model is needed, which can determine relationships among movie contents, or track meaning changes, in order to accurately retrieve the story information. Recently, story-based video analysis techniques have emerged using a social network concept for story information retrieval. These approaches represent a story by using the relationships between characters in a movie, but these approaches have problems. First, they do not express dynamic changes in relationships between characters according to story development. Second, they miss profound information, such as emotions indicating the identities and psychological states of the characters. Emotion is essential to understanding a character's motivation, conflict, and resolution. Third, they do not take account of events and background that contribute to the story. As a result, this paper reviews the importance and weaknesses of previous video analysis methods ranging from content-based approaches to story analysis based on social network. Also, we suggest necessary elements, such as character, background, and events, based on narrative structures introduced in the literature. We extract characters' emotional words from the script of the movie Pretty Woman by using the hierarchical attribute of WordNet, which is an extensive English thesaurus. WordNet offers relationships between words (e.g., synonyms, hypernyms, hyponyms, antonyms). We present a method to visualize the emotional pattern of a character over time. Second, a character's inner nature must be predetermined in order to model a character arc that can depict the character's growth and development. To this end, we analyze the amount of the character's dialogue in the script and track the character's inner nature using social network concepts, such as in-degree (incoming links) and out-degree (outgoing links). Additionally, we propose a method that can track a character's inner nature by tracing indices such as degree, in-degree, and out-degree of the character network in a movie through its progression. Finally, the spatial background where characters meet and where events take place is an important element in the story. We take advantage of the movie script to extracting significant spatial background and suggest a scene map describing spatial arrangements and distances in the movie. Important places where main characters first meet or where they stay during long periods of time can be extracted through this scene map. In view of the aforementioned three elements (character, event, background), we extract a variety of information related to the story and evaluate the performance of the proposed method. We can track story information extracted over time and detect a change in the character's emotion or inner nature, spatial movement, and conflicts and resolutions in the story.

Analysis of Trends in Education Policy of STEAM Using Text Mining: Comparative Analysis of Ministry of Education's Documents, Articles, and Abstract of Researches from 2009 to 2020 (텍스트 마이닝을 활용한 융합인재교육정책 동향 분석 -2009년~2020년 교육부보도, 언론보도, 학술지 초록 비교분석-)

  • You, Jungmin;Kim, Sung-Won
    • Journal of The Korean Association For Science Education
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    • v.41 no.6
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    • pp.455-470
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    • 2021
  • This study examines the trend changes in keywords and topics of STEAM education from 2009 to 2020 to derive future development direction and education implications. Among the collected data, 42 cases of Ministry of Education's documents, 1,534 cases of articles, and 880 cases of abstract of researches were selected as research subjects. Keyword analysis, keyword network and topic modeling were performed for each stage of STEAM education policy through the Python program. As a result of the analysis, according to the STEAM education policy stage, there were differences in the frequency and network of keywords related to STEAM education by media. It was confirmed that there was a difference in interest in STEAM education policy as there were differences in keywords and topics that were mainly used importantly by media. Most of the topics of the Ministry of Education's documents were found to correspond to topics derived from articles. The implications for the development direction of STEAM education derived from the results of this study are as follows: first, STEAM education needs to consider ways to connect multiple topics, including the humanities. Second, since the media has a difference in interest in STEAM education policy, it is necessary to seek a cooperative development direction through understanding this. Third, the Ministry of Education's support for core competency reinforcement and convergence literacy for nurturing future talents, the goal of STEAM education, and the media's efforts to increase the public's understanding of STEAM education are required. Lastly, it is necessary to continuously analyze the themes that will appear in the evaluation process and change STEAM education policy.