• Journal of Biosystems Engineering
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• 제19권3호
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• pp.163-174
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• 1994

This study was conducted to investigate the dynamic motion of knife drive system of combine harvester. A computer program was developed to simulate the dynamic motion of the knife drive linkage and its algorithm was evaluated through experiments. The results are summarized as follows : 1. The theorectical horizontal (the direction of knife's reciprocating motion) reaction forces at the supporting point of rocker arm and crank arm were changed in the similar sinusoidal trends with the measured reaction forces. 2. The maximum values of shaking moment and reaction force per one revolution of crank arm followed polynomial trends as the rotational speed of crank shaft increased. The unbalanced force acting on the driving system increased at high speed. Therefore, the rotational speed of crank shaft should be maintained in proper range at increased forward speed to decrease vibration of the knife drive system. 3. The added mass to the crank arm increased the dynamic unbalanced force at the supporting point of rocker arm. It counterbalanced the reaction force at the supporting point of crank arm.

• 한국지반환경공학회 논문집
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• 제20권9호
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• pp.13-19
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• 2019

Dynamic earth pressure is considered an important parameter in the design of embedded structures. In current engineering design simplified methods developed either for yielding or non-yielding structures are utilized to predict resultant dynamic pressure. The applicability of these equations to embedded structures have not yet been reported. In this study we perform a suite of equivalent linear time history analysis for a range of embedded structure configurations. Numerically calculated dynamic pressure is shown to depend on the flexibility ratio (F), aspect ratio (L/H) of the embedded structure, and ground motion. Increase in L/H and intensity increases the magnitude of dynamic pressure. An increase in F decreases the dynamic pressure. Overall, the trends highlight the need for development of new method that accounts for F and L/H to calculate the dynamic pressure for the performance-based design of embedded structures.

• Earthquakes and Structures
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• 제23권4호
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• pp.353-361
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• 2022

The dynamic behavior of a single pile was investigated by using analytical and numerical studies. The focus of this study was to develop the dynamic p-y curve of a pile for pseudo-static analysis considering the shear wave velocity of the soil by using three-dimensional numerical analyses. Numerical analyses were conducted for a single pile in dry sand under changing conditions such as the shear wave velocity of the soil and the acceleration amplitudes. The proposed dynamic p-y curve is a shape of hyperbolic function that was developed to take into account the influence of the shear wave velocity of soil. The applicability of pseudo-static analysis using the proposed dynamic p-y curve shows good agreement with the general trends observed by dynamic analysis. Therefore, the proposed dynamic p-y curve represents practical improvements for the seismic design of piles.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.113-118
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• 1998

In modern mechatronics new concepts of machines and processes are found by using the collected knowledge of all disciplines and by offering functional solutions. Most of the problems in the field of mechatronics demand technical innovations on the field of actuators, sensors and control methods. It demands also high dynamic drives with power electronics, able to cope with the new requirements. The paper presents some trends and industrial experiences with power components for high dynamic drives.

• 한국문헌정보학회지
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• 제55권4호
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• pp.141-157
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• 2021

본 연구는 국내 인공지능 분야 연구동향을 파악하기 위해 국내 학술지에 발표된 인공지능 분야 논문들을 대상으로 네트워크 분석 및 동적 토픽 모델링 분석을 진행하였다. 2020년까지 KCI(한국학술지인용색인)에 등록된 논문 중 '인공지능'과 'artificial intelligence' 두 개의 키워드 중 하나 또는 하나 이상이 논문 제목 또는 색인 키워드에 포함한 2,552개 논문들의 메타데이터 및 초록을 수집하였다. 키워드, 소속기관, 주제 분야, 초록의 추출 및 전처리 작업을 진행하였고 키워드를 활용한 키워드 동시 출현 네트워크 구축 및 분석으로 국내 인공지능 분야의 주요 키워드를 확인하였으며, 소속기관 정보를 활용한 기관 협력 네트워크를 통해 국내외 산학기관들의 협력 정 도 및 특징을 파악하였다. 또한 연구 대상 논문들 중 한글로 작성된 1845개의 초록 들을 대상으로 동적 토픽 모델링을 진행하였으며, 주제어들을 토대로 13개의 주제를 레이블링하였다. 레이블링 된 13개의 주제를 통해 국내 인공지능 연구 분야의 시기별 주제 동향을 파악하였다. 본 연구는 기존의 선행연구들에서 시도하지 않은 저자 소속기관 등을 활용한 기관 협력 네트워크 및 초록을 활용한 동적 토픽 모델링을 통해 국내 인공지능 분야 연구동향 파악의 시야를 확장하는 것으로 학술적 의의를 지닌다. 또한, 본 연구의 결과가 인공지능 시대에 부합하는 국가 정책 수립 기여라는 실질적 함의를 시사한다.

• Journal of Information Science Theory and Practice
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• 제6권4호
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• pp.39-53
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• 2018

While the body of research on metadata has grown substantially, there has been a lack of systematic analysis of the field of metadata. In this study, we attempt to fill this gap by examining metadata literature spanning the past 20 years. With the combination of a text mining technique, topic modeling, and network analysis, we analyzed 2,713 scholarly papers on metadata published between 1995 and 2014 and identified main topics and trends in metadata research. As the result of topic modeling, 20 topics were discovered and, among those, the most prominent topics were reviewed in detail. In addition, the changes over time in the topic composition, in terms of both the relative topic proportions and the structure of topic networks, were traced to find past and emerging trends in research. The results show that a number of core themes in metadata research have been established over the past decades and the field has advanced, embracing and responding to the dynamic changes in information environments as well as new developments in the professional field.

• 환경영향평가
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• 제9권4호
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• pp.349-362
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• 2000

In the study, the feasibility of landscape ecological measures as indices system for interpretation and evaluation of regional ecosystem was investigated through the application to Yongin City. Each patch metrics well showed the class structure and supplemented the class metrics, and class metrics also showed well the landscape structure and supplemented the landscape metrics. And the change analysis through subtraction of two set of landscape ecological measurement in two point of time showed the dynamic trends very well. One of the dynamic trends in Yongin City was the rapid fragmentation. While there was no landcover data on Yongin City, using Landsat data and remote sensing techniques were proved to be efficient and effective to produce the digital landcover data.

• 전자통신동향분석
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• 제35권5호
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• pp.1-13
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• 2020

Recently, network infrastructure has evolved into a BizTech agile autonomous network to cope with the dynamic changes in the service environment. This survey presents the expectations from two different perspectives of the harmonization of network and artificial intelligence (AI) technologies. First, the paper focuses on the possibilities of AI technology for the autonomous network industry. Subsequently, it discusses how networks can play a role in the evolution of distributed AI technologies.

• 한국측량학회지
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• 제35권5호
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• pp.329-338
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• 2017

This study attempts to classify 1008 alley markets in Seoul through cluster analysis using Dynamic Time Warping, one of the methods used to analyze the similarity of time series, and evaluate the possibility of opening new stores. The sequence of the gross sales of an alley market and that of gross sales per store stand for the potential of growth and profitability of the market, respectively and are used as variables for cluster analysis. Five clusters are obtained for the gross sales and four clusters for the gross sales per store. These two types of clusters are again classified as rising and falling trends, respectively, and the combination of these trends produces four categories. These categories are used to evaluate the possibility of opening new stores in alley markets. The results show that the southeast which is relatively wealthy inferior to other regions in opening new stores. Alley markets in the northeast and the southwest are better than other regions such that opening a new store is justified. In the northwest, there are many markets with trend of gross sales and that of gross sales per store moving in opposite directions, and new store openings in these markets should be postponed.

• 전자통신동향분석
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• 제35권2호
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• pp.17-27
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• 2020

Predicting where and when a crime may occur in an area of interest is one of many strategies of predictive policing. Multidimensional analysis, including CCTV, can overcome the limitations of hotspot prediction, especially of violent crimes. In order to identify the precursors of a crime, it is necessary to analyze dynamic data such as attributes and activities of people, social information, environmental information, traffic flows, and weather. These parameters can be recognized by CCTV. In addition, it provides accurate analysis of the circumstances of a crime in a dynamic situation, calculates the risk, and predicts the probability of a crime occurring in the near future. Additionally, it provides ways to gather historical criminal datasets, including sensitive personal information.