• Title/Summary/Keyword: Pointing Loss

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Implementation and Performance Analysis of the Single Channel Monopulse System (단일채널 모노펄스시스템의 구현 및 성능 검증)

  • Kang, Byoung-Wook;Kwon, Hyuk-Ja;Lee, Young-Jin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.10
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    • pp.900-908
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    • 2016
  • In this paper, we have studied the tracking system with a single channel monopulse receiver that has a comparative advantage of costs, size, weight, and power consumption over the general 3-channel monopulse receivers. After the single channel monopulse system was composed of an antenna, a monopulse receiver, a servo unit, a RF signal processor unit and a power supply unit, we analyzed the basic tracking performance of the tracking error angle and the pointing loss. And we proved the tracking performance to a moving target in the outdoor environment. On the Analysis of the tracking test results, the single channel monopulse system shows a equal or higher performance over the general 3-channel monopulse system and also has advantages of the system implementation. Also, it is concluded that this study is useful to apply a single channel monopulse receiver with benefits of production price and miniaturization when the monopulse tracking systems will be developed in the future.

Development of phase shifter for Ka-band Passive Phase Array Seeker and Seeker Performance Analysis due to the Phase Error of Phase Shifter (Ka-대역 수동위상배열탐색기용 위상 변위기 개발 및 변위기 위상 오차에 의한 탐색기 성능 분석)

  • Kim, Youngwan;Woo, Seon-keol;Kwon, Jun-beom;Kang, Yeon-duk;Park, Jongkuk
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.19 no.3
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    • pp.149-155
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    • 2019
  • In this paper, phase shifter has been designed and manufactured to apply to passive phase array seeker for Ka-band and its performance was confirmed. It was designed as a key element for conducting electric beam steering by adjusting the phase of the array element. Insertion loss of less than 1.5dB and phase accuracy of less than $10^{\circ}$(RMS) in operation bandwidth of 1GHz were checked. The performance identified by the actual fabrication was further analyzed by applying the beam pattern analysis based on the array synthesis theory. The effect of the final performamnce of the proven phase shifter on the performance and pointing error and angular accuracy of the passive phase array antenna beam pattern was analyzed. Then, the validation of the proposed phase shifter has been made.

Manufacturing and Characteristic Evaluation of Free space Optical Communication Devices in 5G Mobile Base Stations for Emergency Disaster Response (긴급재난 대응용 5G 이동 기지국을 위한 대기공간 광통신 장치의 제작과 특성평가)

  • Jin-Hyeon Chang
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.5
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    • pp.131-138
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    • 2023
  • In this paper, a free space optical communication device that can be used in a mobile base station of several km or less was fabricated and its characteristics were investigated. To overcome the loss due to atmospheric transmission, an optical fiber amplifier (EDFA) with an output of 23 dBm or more was used. In order to increase the focusing speed and miniaturization of the laser beam, an optical lens was manufactured, and a transmission lens was designed to have beam divergence within the range of 1.5 to 1.8 [mrad]. A PT module that controls PAN/TILT was fabricated in order to reduce pointing errors and effective automatic alignment between transceiver devices. In this study, Reed-Solomon (RS) code was used to maintain the transmission quality above a certain level. It was manufactured to be able to communicate at a wireless distance of 300m in a weather situation with visibility of 300m. For performance measurement, it was measured using BERT and eye pattern analyzer, and it was confirmed that BER can be maintained at 2.5Gbps.

A New Horizon of Understanding of the Faith Community Based on the Concept of Immunity between Ecclesia and Esposito (에클레시아와 에스포지토의 면역 개념에 입각한 신앙공동체 이해의 새 지평)

  • Yang, Seung-Joon
    • Journal of Christian Education in Korea
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    • v.62
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    • pp.161-186
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    • 2020
  • This study was conducted with the aim of opening a new horizon in understanding the church, which is a community of faith, in the context of losing social credibility with selfishness and closedness, and spreading social distance due to the epidemic. First, the concept and meaning of 'Ecclesia', a representative term for the church, was studied historically, biblically, and theologically, and Paul's intention was frequently used. Second, we explored the new horizons of the community of faith through a discussion of Roberto Esposito's Communitas and Immunitas, which unraveled the relationship between community and individual with an immunological concept. Not only dis lose social trust for a variety of reasons, but it has been pointed out as a target of social distancing due to the spread of the epidemic virus and is facing a crisis of weakening or loss of the faith community of the "church". Since the second epidemic has been predicted since Covid-19, the partial loss of daily life and the weakening and loss of meeting worship and fellowship in the church are inevitable. The church in the future needs to transform and build a true community of faith that understands the concept of immunity and can lead the transformation of society while revealing the spirit and life scent of Jesus Christ. To this end, innovation and practice of the paradigm of the community of faith appropriate to the rapidly changing times and situations is required. In Chapter 1 of this paper, we propose innovation by pointing out the problems of the church and the faith community, which have lost social credibility, and which are the objects of social distance, with selfishness and closedness. Chapter 2 studies and analyzes the 'Ecclesia' used in ancient Greek to transform the paradigm of the faith community, and identifies the intention of the apostle Paul to apply the 'Ecclesia' to the church's faith community. Chapter 3-4 discusses the concept of immunity, summarizes the reinterpretation of Esposito, who looked at the relationship between the individual and the community through the concept of positive immunity beyond negative immunity. And It draws application points for transforming the faith community of various communities, individuals, and churches. In conclusion, Chapter 5 restores precious gatherings and participation that are weakened and lost through the meaning of 'Ecclesia' and suggests expansion to higher level public gatherings and democratic participation. In addition, based on the reinterpretation of the concept of immunity, we present unity in diversity and diversity in unity as alternatives to the church and community of faith.

Link between Periodontal Disease and Cancer: A Recent Research Trend (염증-치주 질환과 암에 관한 최근 연구 동향)

  • Lee, Shin Hwa;Choi, Yung Hyun
    • Journal of Life Science
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    • v.23 no.4
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    • pp.602-608
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    • 2013
  • The multifaceted role of chronic inflammation in multistep carcinogenesis has been extensively investigated and well documented. Periodontal diseases are associated with multifactorial agents, including bacterial endotoxins and the generation of an inflammatory response, indicating that poor oral health is associated with a variety of systemic diseases. The association between poor oral health, chronic inflammation, smoking, and increased alcohol consumption as risk factors for tumorogenesis is well established. More recently, associations between oral health and tooth loss and gastric, lung, and pancreatic cancers have been explored, with some studies pointing to smoking and oral health as a common link with an increased risk for malignant disease. In addition, epidemiological studies consistently indicate increased risks of various cancers with periodontal disease or poor oral condition caused by oral bacteria, which may activate alcohol- and smoking-related carcinogens locally or act through chronic inflammation. Appropriate oral care is vital in preventing cancer, as well as many other diseases. Thus, research on the correlation between oral care and periodontal inflammation and cancer is required. This review highlights the association between oral health and the risk of certain malignancies, such as periodontal disease-associated chemoprevention of inflammation" in this sentence.

Automatic Text Summarization based on Selective Copy mechanism against for Addressing OOV (미등록 어휘에 대한 선택적 복사를 적용한 문서 자동요약)

  • Lee, Tae-Seok;Seon, Choong-Nyoung;Jung, Youngim;Kang, Seung-Shik
    • Smart Media Journal
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    • v.8 no.2
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    • pp.58-65
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    • 2019
  • Automatic text summarization is a process of shortening a text document by either extraction or abstraction. The abstraction approach inspired by deep learning methods scaling to a large amount of document is applied in recent work. Abstractive text summarization involves utilizing pre-generated word embedding information. Low-frequent but salient words such as terminologies are seldom included to dictionaries, that are so called, out-of-vocabulary(OOV) problems. OOV deteriorates the performance of Encoder-Decoder model in neural network. In order to address OOV words in abstractive text summarization, we propose a copy mechanism to facilitate copying new words in the target document and generating summary sentences. Different from the previous studies, the proposed approach combines accurate pointing information and selective copy mechanism based on bidirectional RNN and bidirectional LSTM. In addition, neural network gate model to estimate the generation probability and the loss function to optimize the entire abstraction model has been applied. The dataset has been constructed from the collection of abstractions and titles of journal articles. Experimental results demonstrate that both ROUGE-1 (based on word recall) and ROUGE-L (employed longest common subsequence) of the proposed Encoding-Decoding model have been improved to 47.01 and 29.55, respectively.

The Study on Compilation Consciousness and Aspect of Personage Adoption of "Ilsayusa" (『일사유사(逸士遺事)』의 편찬 의식과 인물 수록 양상)

  • Cho, Jihyoung
    • (The)Study of the Eastern Classic
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    • no.70
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    • pp.495-524
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    • 2018
  • This study investigated the literary theory of Jang Jiyeon and his compilation consciousness of the historical biography, and based on this, the study examined the aspect and characteristic of the personage adoption of "Ilsayusa". To figure out the characteristic of "Ilsayusa", this study attempted to investigate the Jang Jiyeon's cognition on epic literature first. Jang Jiyeon had interest in the historical biography in his early days. But he clearly expressed the negative position about the novels which had been handed down from old times, mentioning about their harmful effect, even though they were in a big popularity. The good readings he thought was supposed to be helpful for person's work, study, personality and even the custom, so it is thought that the compilation of "Ilsayusa" was planned as a part of a usefulness to help readers' actual lives by summarizing Jang Jiyeon's philosophy as the form of a historical biography of personages who had actually existed. The direct motivation and the awareness of the problem to compile "Ilsayusa" could be confirmed by the postscript he left. Pointing that Joseon's policy of appointing persons of ability resulted in the loss of the nation, Jang Jiyeon paid attention to the classical scholars from low class, people from under middle class and the local figures in Hamgyeongdo and Pyeongando in the process of compiling "Ilsayusa". Along with this, a kind of a sense of duty that the old heritage must be examined by descendents was manifested as the compilation of "Ilsayusa". Through this, Jang Jiyeon tried to show the good model to the readers of "Ilsayusa" what the way of living would be for raising their volition and keeping the fundamentals. The tendency and characteristic of compiling personages in "Ilsayusa" could be sorted in a few ways as written below. First, it includes all kinds of all actually existed episodes while he was collecting various historical biographies published before. Second, it includes the new kinds of personages paying particular attention to figures of middle class and commoners. Third, it compiled the female figures in a great volume and described new model of woman. Fourth, for areas, it has episodes of all areas in the nation including Pyeongando and Hamgyeongdo. Thinking about all the discussion above, we could estimate that "Ilsayusa" is the definitive edition of these kinds of books which inherited all performances of the biographical literature in better way, which had been accomplished in 19th century.