• Title/Summary/Keyword: line sources

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Optimal Transducer Positions of an Active Noise Control System with an Opening in an Enclosure (능동방음벽 시스템에서의 제어음원 위치에 관한 고찰)

  • 백광현
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.2
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    • pp.164-171
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    • 2004
  • Active control techniques have been used in wide areas of noise and nitration control engineering and a noise barrier is one of them. Omoto's work in 1993 would be one of the fundamental and systematic studies on the actively controlled noise barrier, in which he used equal number of control sources and error sensors. The error sensors were placed uniformly along the top edge of the noise barrier with equal distance apart and the control sources were placed in the exactly same way some distance apart from the error sensors. Since then, a couple of studies were made on the secondary sources'arrangement rather than the optimality of secondary source positions. Shao's results showed that arc shaped arrangement for secondary sources is better than the straight line one, and later work of Yang showed that the more important factor is the average distance between the primary source and secondary sources. However, since these studies were all executed with a simple uniform distribution of the secondary sources along the straight line or arc, it is difficult to conclude which arrangement is superior In order for the fare comparison. the optimality of the source positions in each arrangement must be given in prior. The primary goal of this study is focused on this aspect and some major factors were investigated and compared. The computer simulation results showed that the arc shaped arrangement is marginally better than the straight line one, and more importantly slightly tuned position can greatly improve the performance of the control system.

TIME VARIATION OF SiO (v=1, J=2-1) MASERS OF LONG PERIOD VARIABLES

  • LEE SANG GAK;KIM EUNHYEUK;LEE HYUNG MOK
    • Journal of The Korean Astronomical Society
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    • v.27 no.2
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    • pp.133-146
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    • 1994
  • We have detected a SiO maser line (v=1, J=2- 1) for 15 stars out of about 80 long period variables in the wide range of period. No new sources are detected; all detected sources are variables with period longer than 300 days; no evidence is found that the dust grains in the outer envelope have influenced on this line. The time variation of this maser line for 7 stars, T Cep, ${\mu} Cep$, U Her, R Leo, R Lmi, U Ori, and R Ser is observed and compared with optical light curve at the same epoch of maser observation. No universial relation between the time variation and the optical light curve is found. It implies that the radiation from a central star does not much play an important role for the direct pumping of the SiO maser line.

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Research on Line Overload Emergency Control Strategy Based on the Source-Load Synergy Coefficient

  • Ma, Jing;Kang, Wenbo;Thorp, James S.
    • Journal of Electrical Engineering and Technology
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    • v.13 no.3
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    • pp.1079-1088
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    • 2018
  • A line overload emergency control strategy based on the source-load synergy coefficient is proposed in this paper. First, the definition of the source-load synergy coefficient is introduced. When line overload is detected, the source-load branch synergy coefficient and source-load distribution synergy coefficient are calculated according to the real-time operation mode of the system. Second, the generator tripping and load shedding control node set is determined according to the source-load branch synergy coefficient. And then, according to the line overload condition, the control quantity of each control node is determined using the Double Fitness Particle Swarm Optimization (DFPSO), with minimum system economic loss as the objective function. Thus load shedding for the overloaded line could be realized. On this basis, in order to guarantee continuous and reliable power supply, on the condition that no new line overload is caused, some of the untripped generators are selected according to the source-load distribution synergy coefficient to increase power output. Thus power supply could be restored to some of the shedded loads, and the economic loss caused by emergency control could be minimized. Simulation tests on the IEEE 10-machine 39-bus system verify the effectiveness and feasibility of the proposed strategy.

On-line Temperature Monitoring of the GIS Contacts Based on Infrared Sensing Technology

  • Li, Qingmin;Cong, Haoxi;Xing, Jinyuan;Qi, Bo;Li, Chengrong
    • Journal of Electrical Engineering and Technology
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    • v.9 no.4
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    • pp.1385-1393
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    • 2014
  • Gas insulated switchgear (GIS) is widely used in the power systems, however, the contacts overheating of the inside circuit breaker or disconnector may be a potential cause of developing accidents. As the temperature of the contacts cannot be directly acquired due to existence of the metallic shield, an infrared sensor is adopted to directly measure the temperature of the shield and then the contacts temperature can be indirectly obtained by data fitting, based on which the on-line temperature monitoring technology specifically for GIS contacts based on infrared sensing is proposed in this paper. A real GIS test platform is constructed and experimental studies are carried out to account for the influential factors that affect the accuracy of the infrared temperature measurement. A heat transfer model of the GIS module is also developed, together with experimental studies, the nonlinear temperature relationship among the contacts, the metallic shield and the environment based on a neural network algorithm is established. Finally, an integrated on-line temperature monitoring system for the GIS contacts is developed for on-site applications.

Korean traditioinal village's spaces and human moving line system (전통마을 공간의 동선구조분석 - 한개ㆍ한잠마을의 길을 대상으로 -)

  • 김용수;나정화;박수국
    • Journal of the Korean Institute of Landscape Architecture
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    • v.25 no.3
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    • pp.25-34
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    • 1997
  • As you know, there are a lot of our own traditional folk village exist in Korea, our country. Most people just know is that Korean traditional village is just happen make it and just continuously keeping this times type. But this village is not just make it but made by serious scientific sources such as, rule of locating streets. There are three very important reasons why I research this topic for my research paper. The first important reason is that Korean traditional villages have the pattern of human moving line system in accordance with hyung-kug. Hangae village that located on inclined ground named baesanimsu has the longer human moving line than Hanbam village that located on level ground. The second important reason is that Korean traditional villages have the smaller human moving line of the length and the amplitude as long as going inside villages. But the unit of the amplitude is the larger. Hanae and Hanbam village is the same pattern. The third important reason is that Korean traditional villages have the smaller human moving line of the length and the amplitude as long as having the larger gradient. Hangae and hanbam village is the same pattern. And Hanbam village hast he bigger human moving line of the length, the amplitude and the unit of the amplitude. In conclusion, by these three important big reasons, Korean traditional village is built by scientific sources. And now we can say that our old generation was very unbelievable genius. By these reasons we have to make sure when we make another city town and farm village planning. The meaning of making sure is that a person who have responsibility for making city have to make plan by scientific sources. It has to be not only theoretical but also think about real human life. It also fit on our traditional.

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Evaluation and Seed Increase of Sources of Resistance to Phytophthora capsici in Pepper (고추 역병 저항성 재료의 특성평가와 종자 증식)

  • Kim, Dong-Woo;Kim, Byung-Soo;Bae, Su-Yeon;Han, Jeong-Hye
    • Current Research on Agriculture and Life Sciences
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    • v.20
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    • pp.83-90
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    • 2002
  • Resistance to Phytophthora Capsici and horticultural characteristics of selections from the resistance sources such as PI123469, PI201234, PI201232, AC2258 (=Line 29), CM334, KC268, KC358, KC820, KC821, KC822, KC823 (Line 29), KC462, KC463, KC464 were evaluated and recorded in the process of seed increase. Selections of PI123469, PI201234, PI201232, AC2258, KC823 (Line 29 = AC2258) of them showed the highest level of resistance. A considerable difference in the level of resistance was observed between lines selected from the same sources. The variation between selections derived from the same source was thought to be attributable to natural cross-pollination that may have occurred during the seed increase. Therefore, securing self-pollinated seed by wrapping the flower buds before anthesis would be necessary to obtain genetically pore resistant lines. The next alternative would be to increase the seed in small net houses for single line or field cage.

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Catalog of the Paα-emitting Sources observed in the Carina Region

  • Kim, Il-Joong;Pyo, Jeonghyun;Jeong, Woong-Seob
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.66.2-66.2
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    • 2021
  • We list up the Paα-emitting sources observed in the Carina Region (l = 276°-296°) using the MIRIS Paα Galactic Plane Survey data. A total of 201 sources are cataloged. Out of them, 118 sources are coincident with those in the WISE H II region catalog. 52 H II region candidates are newly confirmed as definite H II regions by detecting the Paα recombination lines. For the remaining 83 sources, we search the corresponding objects in the SIMBAD database. 26 point-like sources are associated with planetary nebulae or emission-line stars (such as Wolf-Rayet and Blue supergiant stars). Also, we carry out aperture photometry to measure Paα fluxes for the sources that show circular features without overlapping with other bright sources. For the whole Galactic Plane, the complete Paα-emitting source catalog is in progress.

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A Study on the Phased Cultural Product Design with Characteristics of Unlined Cheollik in Early 17th Century and Baby Typed Doll's Body (17세기 초 홑철릭 유물의 시대특성과 유아형 인형의 체형특성을 응용한 단계별 복식문화상품 디자인 연구)

  • Choi, Jeong
    • Fashion & Textile Research Journal
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    • v.19 no.4
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    • pp.385-399
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    • 2017
  • This study will broaden the application of doll costume product with historical characteristics and the image of unlined cheollik in the $17^{th}$ century period of transition during the Joseon Dynasty. Historical design sources were extracted from old documents and precedent studies. Unlined cheollik of Shin Gyeong-yu, meritorious retainer, were selected as main reference-relic because of various fabric, preserved conditions and definite shape. 'Baby doll' was selected as main model because of consumer preferences and awareness. Design sources from unlined cheollik in the early $17^{th}$ century were about a 1:2 ratio of upper and under parts, removable separated doori-somae, knife-shaped collar (outside), projected square collar (inside), long pleats line, side slit, traditional flat fell seam sewing. Trapezoidal side line, round waistline, and thin fabric were applied in designs because of toddler-body of doll model. Three designs were produced in step 1: Cheollik A focusing on the historical remake (traditional type), Cheollik B with belt and side slit (crossover type), and Cheollik C with back- opening (modern type). In step 2, interview with fashion major student was conducted to increase the utility of designs. As a result, modern trend sources (frill, velcro, round armhole line, slope of sleeves, and floral pattern) were reflected in Cheollik B, C. Finally, three doll cheollik and cheollik-styled doll apron sample were produced. Various versions must be suggested in the study of doll costume products with traditional sources that balance historical characteristics and practicality to improve customer satisfaction.

An Application of NN on Off-line PD Diagnosis to Stator Coil of Traction Motor (견인전동기용 고정자 코일의 Off-line 부분방전 진단을 위한 NN의 적용)

  • Park, Seong-Hee;Lim, Kee-Joe;Kang, Seong-Hwa
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.8
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    • pp.766-771
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    • 2005
  • In this study, PD(partial discharge) signals which occur at stator coil of traction Motor are acquired these data are used for classifying the PD sources. NN(neural network) has recently applied to classify the PD pattern. The PD data are used for the learning process to classify PD sources. The PD data come from normal specimen and defective specimens such as internal void discharges, slot discharges and surface discharges. PD distribution parameters are calculated from a set of the data, which is used to realize diagnostic algorithm. NN which applies distribution parameters is useful to classify the PD patterns of defective sources generating in stator coil of traction motor.

Diffusion Kinetics of Si in GaAs and Related Defect Chemistry (GaAs에서의 Si의 확산기구와 그에 관련된 격자 결함 화학)

  • Lee, Gyeong-Ho
    • ETRI Journal
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    • v.11 no.4
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    • pp.75-83
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    • 1989
  • The diffusion mechanism of Si in GaAs was investigated using different diffusion sources based on the Si-Ga-As ternary phase equilibria. The Si profiles are measured with secondary ion mass spectrometry and differ significantly for sources taken from the different phase fields in the ternary phase diagram. Neutral As vacancy diffusion is proposed for acceptor Si diffusion anneals using a Ga - Si - GaAs source. Donor Si diffusion using As - rich sources and a Si -GaAs tie line source shows concentration dependent diffusion behavior. Concentration dependent diffusion coefficients of donor Si for As - rich source diffusion were found to be related to net ionized donor concentration and showed three regimes of different behavior: saturation regime, intermediate regime,and intrinsic regime. Ga vacancies are proposed to be responsible for donor Si diffusionin GaAs: $Si_Ga^+V_Ga^-$ (donor Si -acceptor Gavacancy) complex for the extrinsic regime and neutral $V_G$a, for the intrinsic regime.The Si - GaAs tie line source resulted in two branch profiles, intermediate between the As - rich and the Ga - rich source diffusion cases.

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