• Title/Summary/Keyword: Frequency focusing

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Research Trend on Internet of Things and Smart City Using Keyword Fequency and Centrality Analysis : Focusing on United States, Japan, South Korea (키워드 빈도와 중심성 분석을 이용한 사물인터넷 및 스마트 시티 연구 동향: 미국·일본·한국을 중심으로)

  • Lee, Taekkyeun
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.18 no.3
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    • pp.9-23
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    • 2022
  • This study aims to examine research trends on the Internet of Things and smart city based on papers from the United States, Japan, and Korea. We collected 7113 papers related to the Internet of Things and smart city published from 2016 to 2021 in Elsevier's Scopus. Keyword frequency and centrality analysis were performed based on the abstracts of the collected papers. We found keywords with high frequency of appearance by calculating keyword frequency and identified central research keywords through the centrality analysis by country. As a result of the analysis, research on security, machine learning, and edge computing related to the Internet of Things and smart city were the most central and highly mediating research conducted in each country. As an implication, studies related to deep learning, cybersecurity, and edge computing in Korea have lower degree centrality and betweenness centrality compared to the United States and Japan. To solve the problem it is necessary to combine these studies with various fields. The future research direction is to analyze research trends on the Internet of Things and smart city in various regions such as Europe and China.

Research Trend Analysis of the Retail Industry: Focusing on the Department Store (유통업태 연구동향 분석: 백화점을 중심으로)

  • Hoe-Chang YANG
    • The Journal of Economics, Marketing and Management
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    • v.11 no.5
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    • pp.45-55
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    • 2023
  • Purpose: As one of the continuous studies on the offline distribution industry, the purpose of this study is to find ways for offline stores to respond to the growth of online shopping by identifying research trends on department stores. Research design, data and methodology: To this end, this study conducted word frequency analysis, word co-occurrence frequency analysis, BERTopic, LDA, and dynamic topic modeling using Python 3.7 on a total of 551 English abstracts searched with the keyword 'department store' in scienceON as of October 10, 2022. Results: The results of word frequency analysis and co-occurrence frequency analysis revealed that research related to department stores frequently focuses on factors such as customers, consumers, products, satisfaction, services, and quality. BERTopic and LDA analyses identified five topics, including 'store image,' with 'shopping information' showing relatively high interest, while 'sales systems' were observed to have relatively lower interest. Conclusions: Based on the results of this study, it was concluded that research related to department stores has so far been conducted in a limited scope, and it is insufficient to provide clues for department stores to secure competitiveness against online platforms. Therefore, it is suggested that additional research be conducted on topics such as the true role of department stores in the retail industry, consumer reinterpretation, customer value and lifetime value, department stores as future retail spaces, ethical management, and transparent ESG management.

A study on recent research trends related to infant & children's clothes (최근 유·아동복 관련 연구 동향에 관한 연구)

  • Kim, Yun Hee;Lee, Jin Hee
    • Journal of the Korea Fashion and Costume Design Association
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    • v.20 no.4
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    • pp.175-186
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    • 2018
  • These days, due to increased income levels, lower birthrate, and increased marriage age, interest and investment in children has increased, and infant & children's clothes has become more upgraded, differentiated, and diversified. In accordance with the change of the infant & children's clothes market, Examine the research trends of the papers in the journals. Used 'KISS', 'DBpia', 'Korea Institute of Science and Technology Information', in the search system, and 137 papers were searched for by using key word, 'infant's clothes' and 'children's clothes'. The year of publication is limited to 2001 to 2017, and they are classified into 5-year units and again the papers were classified by year, by journal, by field of clothing research (Technical Design & Production, Fashion Marketing, Textile System, Fashion Design), and frequency and percentage were used as data analysis. The number of articles related to infant & children's clothes increased such as 39 in 2001~2005, 43 in 2006~2010, and 55 in 2011~2017. The distribution of articles by journals has been published mainly in the journal of the Korean Society of Clothing and Textiles, but as the journals were diversified, they were distributed evenly in other journals related to the apparel. In the presentations according to the research field by year, from 2001 to 2005, the ratio of apparel design and production was high, but since 2006, many papers related to fashion marketing and fashion design have been published. The research contents of the field of clothing research are as follows: 41 articles in design production field, focusing on dimensional system and pattern design, 40 articles in fashion design field, focusing on design development and design preferences, 46 articles in fashion marketing field, focusing on consumer behavior and marketing management. And 10 articles in apparel material system field, focusing on research on cloth science materials, but they are less well studied than others, but these studies should be actively pursued in the future.

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ITU-R Study on Frequency Sharing for Mobile Satellite Services (ITU-R의 이동위성업무 주파수 공유 연구 현황)

  • B.J. Ku;D.S. Oh
    • Electronics and Telecommunications Trends
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    • v.38 no.1
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    • pp.55-64
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    • 2023
  • Recently, preparations for 6G have led to the increasing interest in integrated or hybrid communication networks considering low-orbit satellite communication networks with terrestrial mobile communication networks. In addition, the demand for frequency allocation for new mobile services from low-orbit small satellites to provide global internet of things (IoT) services is increasing. The operation of such satellites and terrestrial mobile communication networks may inevitably cause interference in adjacent bands and the same band frequency between satellites and terrestrial systems. Focusing on the results of the recent ITU-R WP4C meeting, this study introduces the current status of frequency sharing and interference issues between satellites and terrestrial systems, and frequency allocation issues for new mobile satellite operations. Coexistence and compatibility studies with terrestrial IMT in L band and 2.6 GHz band, operated by Inmassat and India, respectively, and a new frequency allocation study (WRC-23 AI 1.18) are carried out to reflect satellite IoT demand. For the L band, technical requirements have been developed for emission from IMT devices at 1,492 MHz to 1,518 MHz to bands above 1,518 MHz. Related studies in the 2 GHz and 2.6 GHz bands are not discussed due to lack of contributions at the recent meeting. In particular, concerning the WRC-23 agenda 1.18 study on the new frequency allocation method of narrowband mobile satellite work in the Region 1 candidate band 2,010 MHz to 2,025 MHz, Region 2 candidate bands 1,695 MHz to 1,710 MHz, 3,300 MHz to 3,315 MHz, and 3,385 MHz to 3,400 MHz, ITU-R results show no new frequency allocation to narrow mobile satellite services. Given the expected various collaborations between satellites and the terrestrial component are in the future, interference issues between terrestrial IMT and mobile satellite services are similarly expected to continuously increase. Therefore, participation in related studies at ITU-R WP4C and active response to protect terrestrial IMT are necessary to protect domestic radio resources and secure additional frequencies reflecting satellite service use plans.

수동 소나 배열을 이용한 수중 음향 영상에 관한 연구

  • 김형균
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1984.12a
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    • pp.96-99
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    • 1984
  • In this study, the underwater acoustic images were obtained by ultrasonicwave. The experiment was performed in the anechoic watertank, using a passive sonar array for one and two sound source respectively by X-Y scanning technique. The receiving array was consist of 8 disc type transducers with 1.5cm diameter at 25KHz resonance frequency. The scanned data were processed by the FORTRAN IV algorithm for the reconstruction of image, and the image had some noise due to the surface reflected waves. As the result, it was found that the acoustic imaging by electrical deflection and dynamic focusing technique is applicable to SONAR with the suppression of surface reflected wave.

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Analysis of Japanese EEL Learners English Intonation - Japanese and English Compounds -

  • Taniguchi, Masaki
    • Proceedings of the KSPS conference
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    • 2000.07a
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    • pp.88-95
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    • 2000
  • This paper attempts to investigate characteristic features of Japanese EFL learners' English intonation and how their Japanese accents are affecting their English intonation, focusing on a comparison between the accent patterns of Japanese compounds and the stress patterns of English compounds. It is based on research dedicated to helping to improve the teaching and learning of English intonation (prosody) for Japanese EFL learners. It examines the Fundamental Frequency (henceforth Fx) contours of two EFL college students, one specializing in English and the other in Japanese. Both of them may be considered upper intermediate EFL students with their TOEFL (Test of English as a Foreign Language) scores ranging between 500 and 550.

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Temporal characterization of sub-10-fs laser pulses using multi-shot frequency-resolved optical gating technique (다중펄스 주파수분해 광게이팅을 이용한 10 펨토초 미만의 레이저 펄스의 시간특성 측정)

  • 이용수;홍경한;성재희;남창희
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.40-41
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    • 2003
  • (self-focusing)을 이용한 커렌즈 모드록킹(Kerr-lens mode-locking; KLM) 방법을 이용하면 간단한 구조를 갖는 공진기로 100 펨토초(femto=10-13) 미만의 레이저 펄스를 생성할 수 있다. KLM 티타늄사파이어(Ti:sapphire) 레이저의 발달로 10 펨토초 영역의 레이저 펄스를 간단하게 생성할 수 있게 되었으며 특히, 넓은 스펙트럼 폭을 가지는 처프거울(chirped mirror)의 사용과 정확한 분산의 보정을 통한 5 펨토초(800 nm 파장의 두 주기에 해당) 영역의 레이저 펄스 생성도 보고되고 있다.

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An Experimental Analysis on the Pier Dynamic Property Change with Penetration Depths (근입깊이에 따른 콘크리트 교각의 동특성 변화에 관한 실험적 연구)

  • Park, Byung-Cheol;Park, Seung-Bum
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.655-658
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    • 2004
  • This study was performed to verify the possibility of the integrity estimation of the bridge substructure focusing on the dynamic property change of concrete pier with penetration depths using experimental modal analysis. As a result of the impact vibration test, it is found that scour reduces the stiffness of the foundation, and measurement the accelerance residue and natural frequency can be used for the estimation of the integrity index.

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A Study on Cargo Picking Safety Work: Focusing on Rack Work Place (보관작업장 사고방지 예방에 관한 연구: 렉 작업장을 중심으로)

  • Chung, Byung Hyun;Kim, Ki Hong
    • Journal of the Korea Safety Management & Science
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    • v.24 no.3
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    • pp.23-28
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    • 2022
  • Rack is a place to store products. Workers pick products from rack storage. After picking up, workers move to another location by forklift. Driving speed, worker condition, and number/frequency of operation is responsible for forklift accidents. When an accident occurs, products get damaged. Therefore, it is important to prevent one. As the research result, To prevent forklift accidents, the minimum order quantity, the minimum number of operations, and low speed operation are required.

A Mathematical Approach for Modal Frequency Analysis in Actuators (운동방정식 유도에 의한 액추에이터 모드 주파수 분석)

  • Lee, Kyung Taek
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.6
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    • pp.537-545
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    • 2013
  • In this paper, the vibration for actuators having lens module, confined to lateral and torsional directions of suspensions, is described by mathematically analyzing its suspension configuration and motion. In order to prove the accuracy of this result, it is compared to a finite element analysis. Also it is shown that modal frequencies can be modified by changing design parameters in mathematical motion expressions.