• Title/Summary/Keyword: Basic Concept

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Design of Active Power Factor Corrector for Low Power Supply by Loss Free Resistor Concept (무손실 저항개념을 이용한 저전력 전원설비용 능동 역률보정기의 설계)

  • 임영철;정영국;최찬학;나석환;이건식;장영학
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.7 no.1
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    • pp.30-36
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    • 1993
  • A simple discontinuous conduction mode(DCM) flyback type active power factor corrector for low power supply resents an effective resistive load to its power input. It is therefore well suited as an inexpensive high power factor rectifier for office equipment. An equivalent circuit model for the Active Power Factor Corrector based on the "Loss Free Resistor" concept is presented. This simple model correctly describes the basic power processing properties of the Active Power Factor Corrector, including input port resistor emulation, output port power some characteristics.teristics.

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Combustion Stability and the Properties of Methane/Air Mixture Subjected to Unsteady Flow Fluctuations (비정상 유동의 메탄/공기 혼합기 반응안정성 효과 연구)

  • Lee, Eui-Ju;Oh, Chang-Bo
    • Journal of the Korean Society of Safety
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    • v.26 no.5
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    • pp.1-6
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    • 2011
  • Flame extinction and the chemistry of stoichiometric methane/air mixture were investigated numerically in the PSR(perfectly stirred reactor). For the study, PSR code was modified to be possible to unsteady calculation, and the sinusoidal fluctuation was subjected to the residence time. In the region of residence time far from the extinction limit, combustion mode was strongly dependent on the frequency. The low frequency excitation provided the quasi-steady behavior on the temperature and the concentrations of related species, but small variation of temperature was observed under high frequency. In the region of residence time near the extinction limit, the mixture subjected above 1 KHz was still reacting even though extinction had to be occurred under quasi-steady concept. The attenuation of extinction limit resulted from that chemical time was comparable to the flow time. The mean mole fractions of both NO and CO were almost same regardless of imposed frequency. However, the average mole fraction of $C_2H_2$ was decreased as increasing frequency, which implies that soot yield might be reduced at the higher frequency of flow excitation. The result provides the basic concept for flame stabilization, and it will be used to design a mild combustor.

A Survey of Trust Management in WSNs, Internet of Things and Future Internet

  • Chang, Kai-Di;Chen, Jiann-Liang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.1
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    • pp.5-23
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    • 2012
  • Nowadays, most researchers and manufacturers always pay attention on wireless sensor networks (WSNs) due to its potential applications in many regions such as military, industrial and civilian areas. WSNs are the basic components of Internet of Things (IoT) and the key to machine-to-machine communications and the future Internet. Also, the security is an essential element for deploying WSNs. Recently the concept of trust-based mechanism was proposed in WSNs such as traditional cryptographic and authentication mechanisms. However, there is lack a survey on trust management for WSNs, IoT even future Internet. In this paper, we discuss the concept and potential application areas of trust management for WSNs and IoT worlds. Furthermore, we survey different trust management issues (i.e., cluster, aggregation, reputation). Finally, future research directions with respect to trust management in WSNs and future IoT world are provided. We give not only simple WSNs for IoT environments but also a simulated bootstrap platform to provide the discussion of open challenges and solutions for deploying IoT in Future Internet.

A Study on the Conclusion of 「Gwangjeseol」 in 『Dongeuisusebowon』 (『동의수세보원(東醫壽世保元)』 「광제설(廣濟說)」의 결론에 대한 고찰)

  • Hwang, Sabi;Lee, Junhee
    • Journal of Sasang Constitutional Medicine
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    • v.32 no.3
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    • pp.1-7
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    • 2020
  • Objective The purpose of this study was to understand the conclusion of 「Gwangjeseol」 in 『Dongeuisusebowon』 in a more accurate sense. Method We examined the basic viewpoint of Lee je-ma in 「Seongmyeonglon」 in 『Dongeuisusebowon』. Based on the interpretation of the 「Seongmyeonglon」, the viewpoints described in the pathology theory of 『Dongeuisusebowon』 were examined. In addition to 『Dongeuisusebowon』, we looked for contents related to "TuHyeonJilNeung" and "HoHyeonNagSeon" in Lee je-ma's book 『Gyukchigo』 and 『Dongmuyugo』. Result We have found that the meanings of the words "TuHyeonJilNeung" and "HoHyeonNagSeon" in the last article of 「Gwangjeseol」 are not limited to just the 「Gwangjeseol」, but contain the meaning of a topic that runs through the entire book. According to the 『Gyukchigo』 and 『Dongmuyugo』, the meaning of "TuHyeonJilNeung" is related to the "Sa-Bang-Il-Yog", and the "Sa-Bang-Il-Yog" is the "ilsimjiyog" that prevents the practice of "Ji-Haeng". This concept is the same as the concept of "Ji-Haeng" in 「Seongmyeonglon」, the first unit of 『Dongeuisusebowon』. Conclusion It is considered that Lee je-ma wanted to emphasize the reason and mindset to do "Ji-Haeng" by writing the end of the 「Gwangjeseol」, which is the last part of 『Dongeuisusebowon』.

PRELIMINARY SAFETY STUDY OF ENGINEERING-SCALE PYROPROCESS FACILITY

  • Moon, Seong-In;Chong, Won-Myung;You, Gil-Sung;Ku, Jeong-Hoe;Kim, Ho-Dong;Lim, Yong-Kyu;Chang, Hyeon-Sik
    • Nuclear Engineering and Technology
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    • v.46 no.1
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    • pp.63-72
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    • 2014
  • Pyroprocess technology has been considered as a fuel cycle option to solve the spent fuel accumulation problems in Korea. The Korea Atomic Energy Research Institute has been studying pyroprocess technology, and the conceptual design of an engineering-scale pyroprocess facility, called the Advanced Fuel Cycle (AFC) facility, has been performed on the basis of a 10tHM throughput per year. In this paper, the concept of the AFC facility was introduced, and its safety evaluations were performed. For the safety evaluations, anticipated accident events were selected, and environmental safety analyses were conducted for the safety of the public and workers. In addition, basic radiation shielding safety analyses and criticality safety analyses were conducted. These preliminary safety studies will be used to specify the concept of safety systems for pyroprocess facilities, and to establish safety design policies and advance more definite safety designs.

Doris Lessing's Views on Evolution in The Sirian Experiments (『시리우스 제국의 실험』에 나타난 도리스 레싱의 진화에 관한 시각)

  • Min, Kyung Sook
    • Journal of English Language & Literature
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    • v.58 no.4
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    • pp.655-678
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    • 2012
  • Doris Lessing, who considers science and technology as instruments of capitalism, deals with the theme of 'biological evolution' in The Sirian Experiments, the third book in the Canopus in Argos: Archives series. One of her themes that repeats throughout is that of 'spiritual evolution,' and in The Four-Gated City she even used 'biological evolution' as its metaphor. This paper analyzes The Sirian Experiments using scientific knowledge such as the concept of 'biological evolution' from Charles Darwin's evolution theory and Edward O. Wilson's sociobiology. Lessing concludes that while 'biological evolution' not accompanied with 'spiritual evolution' puts humans in existential problems and mental breakdown, the one in equilibrium with the other can bring social and political revolution. Lessing's concept of 'spiritual evolution' is basically a product of her holistic view and her own philosophical view that human evolution is a necessary process following the Universal Order, which shows that she is influenced by Sufism. The basic tenet in Sufi philosophy is to achieve equilibrium between the rational and non-rational modes of consciousness. Lessing incorporates her rational and irrational ideas into The Sirian Experiments to make a field for confluence where the biological, the sociological, and the spiritual thinking converge.

A Basic Study on Mode of Operation for Maritime Autonomous Surface Ship

  • Jeong-Min, Kim;Hye Ri, Park
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2023.05a
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    • pp.162-163
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    • 2023
  • As the development of the 4th industiral revolution in the maritime industry has progressed, the technical development of autonomous ships, and the development of international regulations have been accelerated. In particular, the IMO Maritime Safety Committee(MSC) has established a road-map for the development of the non-mandatory goal-based MASS instrument(MASS Code) and started developing a non-mandatory MASS Code at MSC 105th meeting. Many countries are actively participating in the Correspondence Group on the development of MASS Code, and the development of detailed requirements for MASS functions in the MASS Code is underway. Especially, the concept of "Mode of Operation" for MASS functions was mentioned in the Correspondence Group for the first time, and it is expected that discussions on these modes will be conducted from the IMO MASS JWG meeting to held in April 2023. The concept of "Mode of Operation" will be useful in explaining MASS and MASS functions and will be discussed in the future for the development of MASS Code. This paper reviews the contents of the IMCA M 220 document, which provides guidelines on operating modes, to conduct research on the benchmark for setting the operating modes of MASS.

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Sikh and CaoDai Understandings of Interfaith Harmony: Promoting a Culture of Peace and Understanding

  • Mohammad Jahangir ALAM;Injamam Mahbub MOJUMDER
    • Journal of Daesoon Thought and the Religions of East Asia
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    • v.3 no.1
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    • pp.129-151
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    • 2023
  • The concept of interfaith harmony is one of the key issues for discussion in this contemporary world. It has multifaceted implications that range from pedagogical realms to global policy making. Here we focus on the basic concepts of interfaith harmony from Sikh and Cao Dai perspectives in order to address their viewpoints in regard to promoting culture of Peace and Understanding. Although these religions are new as compared to the existing living religions of the world, they found their new identity in the history of world religions for their unique concepts of interfaith harmony. In this article, the concept of interfaith harmony has been analyzed from two perspectives such as theological and socio-historical. For a systematic understanding of the subject matter, it has been categorized into three subpoints; unity of God, unity of religions and unity of humanity. Methodologically, the qualitative methodological framework of the proposed research is descriptive in nature. Thus, the present research has been primarily conducted by using secondary sources, although the crucial information is collected from primary sources such as the sacred texts of Sikhism and Caodaism. Since this study is done considering the social, political and religious contexts of India and Vietnam, it can contribute to the understanding of the nature of interfaith harmony in South and South-East Asia.

A Study on Village Names of Youngnam Provinces : the Cases of Changnyeong-Gun, Bonghwa-Gun and Namhae-Gun (영남지방 지명에 관한 연구 -창녕군, 봉화군, 남해군의 경우-)

  • Park, Tae-Hwa
    • Journal of the Korean association of regional geographers
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    • v.5 no.1
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    • pp.1-24
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    • 1999
  • This is a study on village names in a plain region of Changnyeong-Gun, a mountain region of Bonghwa-Gun and an island region of Namhae-Gun. The three regions differ in geographical features. The data are based on 455 village names in Changnyeong-Gun, 552 village names in Bonghwa-Gun and 275 village names in Namhae-Gun found in the 1 : 50,000 topographic map. The method of this study is to analyze the word structures of village names in the five basic concepts in geography : Man-Land(Natural Environment and Human Activities). Spatial Relation, Distribution, Region and Transition. The main results of this study are as follows: 1. Naming of villages are related to Natural Environment(41%), Human Activities(23%), Region(17%), Spatial Relation(13%), Distribution(5%), and Transition(3%). Of these six factors, Changnyeong-Gun is relatively dominant in village names related to Spatial Relations, Region and Transition ; Bonghwa-Gun Natural Environment and Namhae-Gun Human Activities and Spatial Relations. But the three Guns are absolutely dominant in village names related to Natural Environment and Human Activities. 2. A village name is divided into the specific name part(given name) and the generic name part(classified name). Names related to Human Activities, Spatial Relations, Distribution and Transition are more frequently found in the specific name part. Therefore, they are used as the given name of a village name. Whereas names related to Natural Environment and Region are more frequently found in generic name part, which means that they are used as the classified name of a village. 3. The word structure of a village name usually has two parts a frontal part(given name) and a rear part(classified name). The two parts have a particular pattern in the geographic concept when they are combined. 1) In the village names related to in their frontal part of the word structure, is more frequently combined as their rear part in Bonghwa-Gun, in Namhae-Gun and in Changnyeong-Gun. 2) In the village names related to in their frontal part of the word structure, is more frequently combined as their rear part in Changnyeong-Gun, in Namhae-Gun and in Bonghwa-Gun. Accordingly, Man(Human Activities) - Land (Natural Environment) can be considered the most important concept in the naming of villages, because the concept is most frequently used in the word structures of village names.

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Development and Implementation of the Analysis Frame for Measurement Activity in Undergraduate Physics Laboratory (대학생들의 물리실험에서 측정 활동 분석틀 개발 및 적용)

  • Shin, Kwang-Moon;Kang, Young-Chang;Lee, Sung-Muk;Lee, Jae-Bong
    • Journal of The Korean Association For Science Education
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    • v.31 no.1
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    • pp.115-127
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    • 2011
  • Analysis frame for undergraduate physics laboratory reports in collecting, processing, and analyzing data was developed. Using the frame and questionaries, we analyzed what difficulties students have in the concepts of error and uncertainty in writing laboratory reports. Students considered repetitive measurement for collecting data, but they didn't express it distinctly in their reports. They also had difficulties in measuring data around the extreme value or the large slope. Especially, most students have had difficulties with error and uncertainty. They can't apply the basic formulation to propagation of error and uncertainty. They also had the difficulties in analyzing data with concepts of error and uncertainty. While most students responded that error and uncertainty is important, there were few students who analyzed the influence of the cause of error on the results quantitatively. The result of the study showed that students have difficulties in writing the laboratory reports because they didn't have the correct concept of the error and uncertainty. So, it is needed to not only teach the physics concept about experiment but to teach basic concept of data collecting, processing, and analyzing specially about error and uncertainty for students as well.