• Title/Summary/Keyword: Power quality measurement

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Developement of Planar Active Array Antenna System for Radar (평면형 능동 위상 배열 레이더용 안테나 시스템 개발)

  • Chon, Sang-Mi;Na, Hyung-Gi;Kim, Soo-Bum;Lee, Jeong-Won;Kim, Dong-Yoon;Kim, Seon-Joo;Ahn, Chang-Soo;Lee, Chang-Hee
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.12
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    • pp.1340-1350
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    • 2009
  • The design and implementation of planar Active Phased Array Antenna System are described in this paper. This Antenna system operates at X-band with its bandwidth 10 % and dual polarization is realized using dual slot feeding microstrip patch antenna and SPDT(Single Pole Double Through) switch. Array Structure is $16\times16$ triangular lattice structure and each array is composed of TR(Transmit & Receive) module with more than 40 dBm power. Each TR module includes digital attenuator and phase shifter so that antenna beam can be electronically steered over a scan angle$({\pm}60^{\circ})$. Measurement of antenna pattern is conducted using a near field chamber and the results coincide with the expected beam pattern. From these results, it can be convinced that this antenna can be used with control of beam steering and beam shaping.

A Study on Journal Impact Measurement with Hirsch-type Indices (학술지 영향력 측정을 위한 h-지수의 응용에 관한 연구)

  • Kim, Pan-Jun;Lee, Jae-Yun
    • Journal of the Korean Society for information Management
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    • v.27 no.1
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    • pp.269-287
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    • 2010
  • The journal impact factor(JIF) of the Thomson Reuters(ISI) has been widely used to assess the impact of journal as well as its quality. However, the JIF contains its critical limitation, in which it does not measure the impact of journal but the average impact of articles in journal. Besides significant number of problems of the JIF has been noticed. Furthermore, given the limited coverage of domestic citation index database in comparison to those of international citation index, it is necessary to apply a more appropriate index with a high level of discriminating power. This study, therefore, aims to introduce some practical methods to measure the impact of domestic journals by using the Hirsch-type indices. As the Hirsch-type indices has been often used for overcoming the limitations of the JIF in worldwide, we hope that our research outcome offers an effective alternative to gauge the impact of journals more accurately. Consequently, using the variations of the h-index($h_s$-index, $f_s$-index) or the sum of issue level(issue based h-index, issue based f-index), we argue that it would improve the discrimination capacity of the Hirsch-type indices significantly and that we can measure the impact of domestic journals more clearly.

Development of Water Level Prediction Models Using Deep Neural Network in Mountain Wetlands (딥러닝을 활용한 산지습지 수위 예측 모형 개발)

  • Kim, Donghyun;Kim, Jungwook;Kwak, Jaewon;Necesito, Imee V.;Kim, Jongsung;Kim, Hung Soo
    • Journal of Wetlands Research
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    • v.22 no.2
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    • pp.106-112
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    • 2020
  • Wetlands play an important function and role in hydrological, environmental, and ecological, aspects of the watershed. Water level in wetlands is essential for various analysis such as for the determination of wetland function and its effects on the environment. Since several wetlands are ungauged, research on wetland water level prediction are uncommon. Therefore, this study developed a water level prediction model using multiple regression analysis, principal component regression analysis, artificial neural network, and DNN to predict wetland water level. Geumjeong-Mountain Wetland located in Yangsan-city, Gyeongsangnam-do province was selected as the target area, and the water level measurement data from April 2017 to July 2018 was used as the dependent variable. On the other hand, hydrological and meteorological data were used as independent variables in the study. As a result of evaluating the predictive power, the water level prediction model using DNN was selected as the final model as it showed an RMSE value of 6.359 and an NRMSE value of 18.91%. This research study is believed to be useful especially as a basic data for the development of wetland maintenance and management techniques using the water level of the existing unmeasured points.

Physicochemical Properties of Endosperm Starch and Breadmaking Quality of Rice Cultivars (쌀 품종의 배유 이화학적 특성에 따른 제빵 적성 비교)

  • Yoon, Mi-Ra;Chun, A-Reum;Oh, Sea-Kwan;Ko, Sang-Hoon;Kim, Dae-Jung;Hong, Ha-Cheol;Choi, Im-Soo;Lee, Jeong-Heui
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.56 no.3
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    • pp.219-225
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    • 2011
  • The physicochemical properties of rice endosperm from five rice varieties and effects of milling on baking bread properties of rice flour were investigated. Five rice varieties exhibited different level of amylose content. The ratio of longer amylopectin chain length to the distribution of endosperm starches was the highest in Goami3. According to the RVA measurement of rice flours, the pasting temperatures of Seolgaengbyeo and Goamibyeo were lower than those of the other rice varieties. There were differences in the changes of swelling power of rice flour under increasing temperature. Each rice flour sample for bread-making was processed into two different particle size by using an air-classification mill, and significant differences were observed among cultivars in the average particle size and damaged starch content of rice flours. Rice flour of Seolgaengbyeo with fine particle size showed the highest value in specific volume after baking.

Quality Characteristics of Fresh Pasta Noodles With Perilla Leaves (들깻잎을 첨가한 생면 파스타 반죽의 품질특성)

  • Kim, Jung-Soo;Song, Soo-Ik
    • Culinary science and hospitality research
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    • v.17 no.2
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    • pp.209-220
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    • 2011
  • This research intends to research on the optimal cooking techniques by adding perilla leaves to raw noodles, in which it has various effects and functions in sterilization. The water content measured in the dough added with raw perilla leaf juice came out high as more perilla leaves were added. More freeze-dried perilla leaf powder decreased water content. The pH of the dough increased significantly as the added ingredients increased with significant differences among the samples. The chromaticity of the dough deliberately decreased in both a and b as the amount of raw perilla leaves in dough increased. The L value of raw noodles with freeze-dried perilla leaves tended to decrease as more ingredients were added. The result of the RVA analysis on the dough with raw perilla leaves showed that the gluten decreased with more raw perilla leaves added. The result of the RVA analysis on the dough with freeze-dried perilla leaf powder indicated that the initial pasting tempo tended to increase significantly with more powder added except for 5% and 7% of powder added with no significant difference. The values dropped as the freeze-dried powder was added Minimum viscosity tended to decrease definitely as more freeze-dried perilla leaf powder was added. The dough's measurement results of WRC showed that water absorbing power of both dough with raw perilla leaves and that with freeze-dried perilla leaf powder reduced significantly as more perilla leaf powder were added.

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Developing an On-Line Monitoring System for a Forest Hydrological Environment - Development of Hardware - (산림수문환경(山林水文環境) 모니터링을 위(爲)한 원거리(遠距離) 자동관측(自動觀測)시스템의 개발(開發) - 하드웨어를 중심(中心)으로 -)

  • Lee, Heon Ho;Suk, Soo Il
    • Journal of Korean Society of Forest Science
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    • v.89 no.3
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    • pp.405-413
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    • 2000
  • This study was conducted to develop an on-line monitoring system for a forest hydrological environment and its meteorological condition, such as temperature, wind direction and speed, rainfall and water level on V-notch, electrical conductivity(EC), potential of hydrogen(PH) by the motor drive sensor unit and measurement with a single-chip microprocessor as controller. These results are summarized as follows ; 1. The monitoring system consists of a signal process unit, motor drive sensor unit, radio modem unit and power supply. 2. The motor drive sensor unit protects the sensor from swift current or freezing and can constantly maintain fixed water level during measurements. 3. This monitoring system can transfer the data by radio modem. Additionally, this system can monitor hydrological conditions in real time. 4. The hardware was made of several modules with an independent CPU. They can be mounted, removed, repaired and added to. Their function can be changed and expanded. 5. These are the result of an accuracy test, the values of temperature, EC and pH measured within an error range of ${\pm}0.2^{\circ}C$, ${\pm}1{\mu}S$ and ${\pm}0.1pH$ respectively. 6. This monitoring system proved to be able to measure various factors for a forest hydrological environment in various experimental stations.

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The Study on Empirical Propagation Path Loss Model in the Antler Terminal Environment (엔틀러 터미널 환경에서 실험적인 패스 로스 모델에 관한 연구)

  • Kim, Kyung-Tae;Kim, Jin-Wook;Jo, Yun-Hyun;Kim, Sang-Uk;Yoon, In-Seop;Park, Hyo-Dal
    • Journal of Advanced Navigation Technology
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    • v.17 no.5
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    • pp.516-523
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    • 2013
  • In this paper, The path loss model of Air Traffic Control(ATC) telecommunication radio channel has been studied at the Incheon International Airport(IIA) with the terminal with two antlers. We measured two frequencies among VHF/UHF channel bands. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponents at passager terminal areas were 3.32 and 3.10 respectively in 128.2 MHz and 269.1 MHz. The deviation of prediction error is 9.69 and 9.65. The new path loss equation at the terminal area was also developed using the derived path loss parameters. The new path loss was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

The Study on Blast Effects of Stemming Materials by Trauzl Lead Block Test and High Speed 3D-DIC Systems (트라우즐 연주시험 및 고속 3차원 이미지영상상관 기법을 이용한 전색재 별 발파효과에 대한 연구)

  • Ko, Younghun;Seo, Seunghwan;Kim, Sik;Chung, Youngjun;Chung, Moonkyung
    • Journal of the Korean Geotechnical Society
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    • v.37 no.10
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    • pp.13-25
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    • 2021
  • The most widely used method for determining the blast effects of explosives is the Trauzl test. This test is used to measure the explosive power (strength) of a substance by determining volume increase, which is produced by the detonation of a tested explosive charge in the cavity of a lead block with defined quality and size. In this paper, Trauzl lead block test and High speed 3D-DIC (Digital Image Correlation) system were conducted to evaluate the stemming effect of the blast hole. The effects of stemming materials can be expressed as the expansion of the cavity in a standard lead block through explosion of the explosives. The blasting experiment was conducted with emulsion explosives. The stemming material in the blast hole of lead block, which was adopted in this study, were using sand and stone chips. Results of blasting experiment and numerical analysis showed that the expansion rates of lead block were most affected by stone chips followed by sand. Also, as result of dynamic strain measurement on the lead block surface of High speed 3D-DIC system, the displacement and surface strain on the block were the highest in the experiment case of stone chips stemming.

Evaluation of Image Quality for Various Electronic Portal Imaging Devices in Radiation Therapy (방사선치료의 다양한 EPID 영상 질평가)

  • Son, Soon-Yong;Choi, Kwan-Woo;Kim, Jung-Min;Jeong, Hoi-Woun;Kwon, Kyung-Tae;Cho, Jeong-Hee;Lee, Jea-Hee;Jung, Jae-Yong;Kim, Ki-Won;Lee, Young-Ah;Son, Jin-Hyun;Min, Jung-Whan
    • Journal of radiological science and technology
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    • v.38 no.4
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    • pp.451-461
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    • 2015
  • In megavoltage (MV) radiotherapy, delivering the dose to the target volume is important while protecting the surrounding normal tissue. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) using an edge block in megavoltage X-ray imaging (MVI). We used an edge block, which consists of tungsten with dimensions of 19 (thickness) ${\times}$ 10 (length) ${\times}$ 1 (width) $cm^3$ and measured the pre-sampling MTF at 6 MV energy. Various radiation therapy (RT) devices such as TrueBeam$^{TM}$ (Varian), BEAMVIEW$^{PLUS}$ (Siemens), iViewGT (Elekta) and Clinac$^{(R)}$iX (Varian) were used. As for MTF results, TrueBeam$^{TM}$(Varian) flattening filter free(FFF) showed the highest values of $0.46mm^{-1}$ and $1.40mm^{-1}$ for MTF 0.5 and 0.1. In NPS, iViewGT (Elekta) showed the lowest noise distribution. In DQE, iViewGT (Elekta) showed the best efficiency at a peak DQE and $1mm^{-1}DQE$ of 0.0026 and 0.00014, respectively. This study could be used not only for traditional QA imaging but also for quantitative MTF, NPS, and DQE measurement for development of an electronic portal imaging device (EPID).

An Empirical Study on How the Moderating Effects of Individual Cultural Characteristics towards a Specific Target Affects User Experience: Based on the Survey Results of Four Types of Digital Device Users in the US, Germany, and Russia (특정 대상에 대한 개인 수준의 문화적 성향이 사용자 경험에 미치는 조절효과에 대한 실증적 연구: 미국, 독일, 러시아의 4개 디지털 기기 사용자를 대상으로)

  • Lee, In-Seong;Choi, Gi-Woong;Kim, So-Lyung;Lee, Ki-Ho;Kim, Jin-Woo
    • Asia pacific journal of information systems
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    • v.19 no.1
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    • pp.113-145
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    • 2009
  • Recently, due to the globalization of the IT(Information Technology) market, devices and systems designed in one country are used in other countries as well. This phenomenon is becoming the key factor for increased interest on cross-cultural, or cross-national, research within the IT area. However, as the IT market is becoming bigger and more globalized, a great number of IT practitioners are having difficulty in designing and developing devices or systems which can provide optimal experience. This is because not only tangible factors such as language and a country's economic or industrial power affect the user experience of a certain device or system but also invisible and intangible factors as well. Among such invisible and intangible factors, the cultural characteristics of users from different countries may affect the user experience of certain devices or systems because cultural characteristics affect how they understand and interpret the devices or systems. In other words, when users evaluate the quality of overall user experience, the cultural characteristics of each user act as a perceptual lens that leads the user to focus on a certain elements of experience. Therefore, there is a need within the IT field to consider cultural characteristics when designing or developing certain devices or systems and plan a strategy for localization. In such an environment, existing IS studies identify the culture with the country, emphasize the importance of culture in a national level perspective, and hypothesize that users within the same country have same cultural characteristics. Under such assumptions, these studies focus on the moderating effects of cultural characteristics on a national level within a certain theoretical framework. This has already been suggested by cross-cultural studies conducted by scholars such as Hofstede(1980) in providing numerical research results and measurement items for cultural characteristics and using such results or items as they increase the efficiency of studies. However, such national level culture has its limitations in forecasting and explaining individual-level behaviors such as voluntary device or system usage. This is because individual cultural characteristics are the outcome of not only the national culture but also the culture of a race, company, local area, family, and other groups that are formulated through interaction within the group. Therefore, national or nationally dominant cultural characteristics may have its limitations in forecasting and explaining the cultural characteristics of an individual. Moreover, past studies in psychology suggest a possibility that there exist different cultural characteristics within a single individual depending on the subject being measured or its context. For example, in relation to individual vs. collective characteristics, which is one of the major cultural characteristics, an individual may show collectivistic characteristics when he or she is with family or friends but show individualistic characteristics in his or her workplace. Therefore, this study acknowledged such limitations of past studies and conducted a research within the framework of 'theoretically integrated model of user satisfaction and emotional attachment', which was developed through a former study, on how the effects of different experience elements on emotional attachment or user satisfaction are differentiated depending on the individual cultural characteristics related to a system or device usage. In order to do this, this study hypothesized the moderating effects of four cultural dimensions (uncertainty avoidance, individualism vs, collectivism, masculinity vs. femininity, and power distance) as suggested by Hofstede(1980) within the theoretically integrated model of emotional attachment and user satisfaction. Statistical tests were then implemented on these moderating effects through conducting surveys with users of four digital devices (mobile phone, MP3 player, LCD TV, and refrigerator) in three countries (US, Germany, and Russia). In order to explain and forecast the behavior of personal device or system users, individual cultural characteristics must be measured, and depending on the target device or system, measurements must be measured independently. Through this suggestion, this study hopes to provide new and useful perspectives for future IS research.