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A Simplified Power Controller in Electronic Ballast of HID Lamp (HID 램프 전자식 안정기의 전력제어기 단순화)

  • Lee, Seung-Hee;Kim, Tae-Won;Park, Tae-Jun;Lee, Chi-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.5
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    • pp.944-949
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    • 2009
  • A simplified power control technique for electronic ballasts of HID lamps is proposed. This power calculator and controller consist of regular operational amplifiers with some passive elements and form simple add operation circuit. From a mathematical model of designed ballast with proposed power controller, the control performance and stability are analyzed by using Matlab and the results show that the stable starting characteristics and steady state characteristics of HID lamp are appropriately guaranteed. The experimental results of the prototype ballast coincide with the simulation results.

Diagnostic of Cast Resin Using Active Infrared Thermal Testing Method (능동열시험법을 이용한 몰드변압기 진단)

  • Lim, Young-Bae;Jeong, Seung-Cheon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07a
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    • pp.481-484
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    • 2004
  • A form of measured temperature distribution to estimate condition of a electrical apparatus is a absolute reference for condition of the apparatus, time rate of transition, and difference between reference and currently temperature. Because passive thermography which has not injection of external thermal stimulation shows difference of temperature being on surface of a structure and temperature difference between the structure and back ground, the result could apply only to estimation or monitor for condition of terminal relaxation and overload related with temperature rising. However, a thermal flow in active thermography is differently generated by structure and condition of surface and subsurface. This paper presents the nondestructive testing using the properties and includes the results by heat injection and cooling to the apparatus. The buried discontinuity of subsurface could be detected by these techniques.

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A analysis of frequency characteristics for the noise cut transformer (노이즈 차폐 변압기의 주파수 특성 분석)

  • Kim, Myoung-Seok;Oh, Joon-Sik;Cho, Hyun-Kil;Han, Gyu-Hwan;Park, Jong-Hwa
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.957-959
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    • 2005
  • A noise reduction equipment in power systems was device combined in a passive element such as the form of L, R and C. A analysis of frequency characteristics for the transformer models shall be considered the additional capacitance between the windings(Cps), terminals(Cs), and winding-ground(Cg). A noise in transformer is modeled by take account into the different frequency. In case of the high frequency, transformer windings with stray capacitance have lower impedance. Therefore a noise is transferred from primary winding to secondary winding. Noise Cut Transformer(NCT) was the noise reduction device and was normally single phase two-winding type transformer. We analyzed frequency characteristics using the nodal network analysis with the equivalent circuit and the simulation of the MATLAB.

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-eullanjira Construction of the Southwestern Dialect in Korea (서남방언의 '-을란지라' 구문 연구)

  • KIM, Ji-eun
    • Korean Linguistics
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    • v.74
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    • pp.1-24
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    • 2017
  • This paper investigated -eullanjira sentence as a kind of construction of the Southwestern dialect in Korea. Five informants were selected to form the main corpus of -eullanjira. Through analyzing the corpus, its semantic, syntactic and morphological characteristics were figured out. Firstly, a view of construction grammar was adopted to capture the semantic and syntactic characteristics of -eullanjira. The construction of -eullanjira was established as "Xdo Yeullanjira Z". Syntactically, -do was found to be a common auxiliary particle, which allowed nouns, adverbs, verbs and adjectives to appear at the position of X, while only verbs and adjectives could appear at the position of Y. Subject-honorific, causative and passive prefinal endings could coexist with Y, while tense and modal prefinal endings could not. Z was an embedded clause, which had the semantic feature of [-DOUBT], meaning 'it should be done undoubtedly'. The formation of -eullanjira was next examined both diachronically and synchronically. It was found there was a conjuntive ending of Middle Korean, corresponding -eullanjira, namely, -landai. Finally, -eullanjira was newly analyzed as [[-eulla-]+[-n-ji-ra]].

Numerical Study on the Extrapolation Method for Predicting the Full-scale Resistance of a Ship with an Air Lubrication System

  • Kim, Dong-Young;Ha, Ji-Yeon;Paik, Kwang-Jun
    • Journal of Ocean Engineering and Technology
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    • v.34 no.6
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    • pp.387-393
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    • 2020
  • Frictional resistance comprises more than 60% of the total resistance for most merchant ships. Active and passive devices have been used to reduce frictional resistance, but the most effective and practical device is an air lubrication system. Such systems have been applied in several ships, and their effects have been verified in sea trials. On the other hand, there are some differences between the results predicted in model tests and those measured in sea trials. In this study, numerical analyses were carried out for a model and a full-scale ship. A new extrapolation method was proposed to improve the estimation of the full-scale resistance of a ship with an air lubrication system. The volume of fluid (VOF) method was considered for the numerical models of the air layer. The numerical method was validated by comparing the experimental data on the air layer pattern and the total resistance.

A study on the Effect of Health of the 24-Form Taegeukkwon (태극권24식(太極拳24式)이 건가(健康)에 미치는 영향(影響)에 대한 소고(小考))

  • Lee, Myoung-Chan;Sa, Hee-Soo;Keum, Kyeong-Soo
    • Journal of Korean Medical classics
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    • v.22 no.2
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    • pp.263-273
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    • 2009
  • Taegeuk is the source and union of the two primary aspects of the cosmos, Eum(陰, Yin) and Yang(陽). The Neo-Confucian philosophers of Chinese Song(宋) dynasty associated Taegeuk with the supreme rational principle of the universe. Taegeuk is a powerful blend of self-discipline, self-defense and healing. It is an art which has grown over the millennia to include hundreds of forms and variations, and can easily take a lifetime to master. Taegeukgwon based on the Taoist philosophies of Eum(陰, Yin) and Yang(陽) is an ancient Eastern form of exercises, characterized by slow reversing movements. There is strong research evidence validating Taegeuk as a safe form of exercise having potential for health promotion and rehabilitation. Today, Taegeukgwon has spread worldwide. The Internal Training of Taegeuk is one of the exercises for regiment. As exercise, Taegeukgwon is designed to provide relaxation in the process of body-conditioning exercise and is drawn from the principles of Taegeuk, notably including the harmonizing of the Eum-yang(陰陽, Yin-yang), respectively the passive and the active principles. It employs flowing, rhythmic, deliberate movements, with carefully individually prescribed stances and positions. In practice, two masters teach the system exactly alike. As a mode of attack and defense, Taegeukgwon resembles Kungfu and is properly considered a martial art. It may be used with or without weapons. Freehand exercise to promote health was practiced in Korea. This training proved to have effect on hypertension, enervation, impotence, premature ejaculation, seminal emission, chronic gastrointestinal diseases, and arteriosclerosis. There have been many schools of Taegeukgwon. Depending on school and master, the number of prescribed exercise forms varies from 24 to 108 or more. The objective of this paper is to reconsider Taegeukgwon and its effect on the body and mind-conditioning in Hwangjenaegyeong(黃帝內經).

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A Study of the Communication Plan in the Display Space of the Trade Fair - Focusing on the Trade Fair Display - (박람회 전시공간의 커뮤니케이션 계획에 관한 연구 - 무역박람회 전시를 중심으로 -)

  • 이우진;신수길
    • Archives of design research
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    • v.14 no.4
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    • pp.179-188
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    • 2001
  • Exhibit space is result that various kinds works of architecture design, interior design, plan and control of exhibit program, embodiment to display space, operation and administration etc. are formed accomplishing creation. Because exhibit space must consider interaction of value that is in dwelled along with the external form about human and exhibits. Therefore, display space of exhibition must achieve functional role that can accomplish communication with spectator as well as function as place that possess products of accumulative value. Therefore, we must establish effective communication plan by position and form of display space as well as properly of exhibits, display contents, exhibit program to achieve purpose of trade fair display. Display space of trade fair can be classed by wall style, corner style, head style, island style, two entrance style 5 according to the position. And we must plan communication plan by these position dividing the function to passive communication area, active communication area, intensive communication area, function achievement area. We will can grope contents and method for successful exhibit through communication plan that is connected form and position of exhibit between exhibit space of such trade fair and we may achieve purpose of trade fair display.

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Historic Status and Grammatical Characteristics of Korean language in the Early 20th Century (한국어사에서 20세기 초 한국어의 위상과 문법 특징)

  • Hong, Jongseon
    • Korean Linguistics
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    • v.71
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    • pp.1-22
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    • 2016
  • The early 20th century is a period of time when Korea confronted with the surging waves of modernization, and made a variety of internal reactions. The Korean language, not immune to the upheaval, also experienced new changes and gradually gained characteristics of today's Korean. Although scholars have not yet fully agreed upon the time division of Korean, Gabo reformation (1896) is usually considered to be the beginning of modern Korean. Thus, the early 20th century was also the beginning of modern Korean. Phonological, lexical, and grammatical characteristics of modern day Korean began to appear during this period of time. Phonologically, the 10 vowel system was established, glottal sounds and aspirated sounds increased, vowel harmony declined. Phenomena such as vowel raising, front-vowelization, monophthongization, and the word-initial rule appeared. Meanwhile, hangul-Chinese mix writing became common practice, and hangul-only writing also started to take place in narrative writing, and elements of spoken language began to reflect in written language. All those pointed to the unification of written and spoken language. Under the influence of modernization, a great amount of new words appeared. Especially, Japanese and other foreign words flooded in in great quantities. Grammatically, '-eos-(-엇-), -neun-(-는-), -ges-(-겟-)' trichotomy system of tenses was established, and hearer-oriented honorific system also formed a binary system of 'hasoseo(하소서), hasibsio(하십시오), hao(하오), hage(하게), haera(해라)' and 'hae (해), haeyo(해요)'. In word formation and sentence construction, the use of '-gi(-기)' became more frequent than '-eum(-음)', while '~geot(~것)' also significantly increased. In negative, causative and passive expressions, the use of long form, which has fewer restrictions than the short form, became more frequent. A tendency towards simplicity appeared. In the same vain, long and complex sentences with several clauses tend to be avoided. Instead, short simple sentences became more favorable. Korean linguistics scholars should pay closer attention to the modernization period, which includes the early 20th century. In order to fully understand today's Korean language, more thorough research on this immediately preceding period is necessary.

Spectral analysis of semi-actively controlled structures subjected to blast loading

  • Ewing, C.M.;Guillin, C.;Dhakal, R.P.;Chase, J.G.
    • Structural Engineering and Mechanics
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    • v.33 no.1
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    • pp.79-93
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    • 2009
  • This paper investigates the possibility of controlling the response of typical portal frame structures to blast loading using a combination of semi-active and passive control devices. A one storey reinforced concrete portal frame is modelled using non-linear finite elements with each column discretised into multiple elements to capture the higher frequency modes of column vibration response that are typical features of blast responses. The model structure is subjected to blast loads of varying duration, magnitude and shape, and the critical aspects of the response are investigated over a range of structural periods in the form of blast load response spectra. It is found that the shape or length of the blast load is not a factor in the response, as long as the period is less than 25% of the fundamental structural period. Thus, blast load response can be expressed strictly as a function of the momentum applied to the structure by a blast load. The optimal device arrangements are found to be those that reduce the first peak of the structural displacement and also reduce the subsequent free vibration of the structure. Semi-active devices that do not increase base shear demands on the foundations in combination with a passive yielding tendon are found to provide the most effective control, particularly if base shear demand is an important consideration, as with older structures. The overall results are summarised as response spectra for eventual potential use within standard structural design paradigms.

Generalized complex mode superposition approach for non-classically damped systems

  • Chen, Huating;Liu, Yanhui;Tan, Ping
    • Structural Engineering and Mechanics
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    • v.73 no.3
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    • pp.271-286
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    • 2020
  • Passive control technologies are commonly used in several areas to suppress structural vibrations by the addition of supplementary damping, and some modal damping may be heavy beyond critical damping even for regular structures with energy dissipation devices. The design of passive control structures is typically based on (complex) mode superposition approaches. However, the conventional mode superposition approach is predominantly applied to cases of under-critical damping. Moreover, when any modal damping ratio is equal or close to 1.0, the system becomes defective, i.e., a complete set of eigenvectors cannot be obtained such that some well-known algorithms for the quadratic eigenvalue problem are invalid. In this paper, a generalized complex mode superposition method that is suitable for under-critical, critical and over-critical damping is proposed and expressed in a unified form for structural displacement, velocity and acceleration responses. In the new method, the conventional algorithm for the eigenvalue problem is still valid, even though the system becomes defective due to critical modal damping. Based on the modal truncation error analysis, modal corrected methods for displacement and acceleration responses are developed to approximately consider the contribution of the truncated higher modes. Finally, the implementation of the proposed methods is presented through two numerical examples, and the effectiveness is investigated. The results also show that over-critically damped modes have a significant impact on structural responses. This study is a development of the original complex mode superposition method and can be applied well to dynamic analyses of non-classically damped systems.