• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.374-390
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• 2021

Growth and yield of field vegetable crops would be affected by climate conditions, which cause a relatively large fluctuation in crop production and consumer price over years. The yield prediction system for these crops would support decision-making on policies to manage supply and demands. The objectives of this study were to compile literatures related to onion and garlic and to perform data-mining analysis, which would shed lights on the development of crop models for these major field vegetable crops in Korea. The literatures on crop growth and yield were collected from the databases operated by Research Information Sharing Service, National Science & Technology Information Service and SCOPUS. The keywords were chosen to retrieve research outcomes related to crop growth and yield of onion and garlic. These literatures were analyzed using text mining approaches including word cloud and semantic networks. It was found that the number of publications was considerably less for the field vegetable crops compared with rice. Still, specific patterns between previous research outcomes were identified using the text mining methods. For example, climate change and remote sensing were major topics of interest for growth and yield of onion and garlic. The impact of temperature and irrigation on crop growth was also assessed in the previous studies. It was also found that yield of onion and garlic would be affected by both environment and crop management conditions including sowing time, variety, seed treatment method, irrigation interval, fertilization amount and fertilizer composition. For meteorological conditions, temperature, precipitation, solar radiation and humidity were found to be the major factors in the literatures. These indicate that crop models need to take into account both environmental and crop management practices for reliable prediction of crop yield.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.401-408
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• 2022

As research on a controlled environment system based on crop growth environment sensing for sustainable production of horticultural crops and its industrial use has been important, research on how to properly utilize soil moisture sensors for outdoor cultivation is being actively conducted. This experiment was conducted to suggest the proper method of utilizing the TEROS 12, an FDR (frequency domain reflectometry) sensor, which is frequently used in industry and research fields, for each orchard soil in three regions in Korea. We collected soils from each orchard where fruit trees were grown, investigated the soil characteristics and soil water retention curve, and compared TEROS 12 sensor calibration equations to correlate the sensor output to the corresponding soil volumetric water content through linear and cubic regressions for each soil sample. The estimated value from the calibration equation provided by the manufacturer was also compared. The soil collected from all three orchards showed different soil characteristics and volumetric water content values by each soil water retention level across the soil samples. In addition, the cubic calibration equation for TEROS 12 sensor showed the highest coefficient of determination higher than 0.95, and the lowest RMSE for all soil samples. When estimating volumetric water contents from TEROS 12 sensor output using the calibration equation provided by the manufacturer, their calculated volumetric water contents were lower than the actual volumetric water contents, with the difference up to 0.09-0.17 m³·m^-3 depending on the soil samples, indicating an appropriate calibration for each soil should be preceded before FDR sensor utilization. Also, there was a difference in the range of soil volumetric water content corresponding to the soil water retention levels across the soil samples, suggesting that the soil water retention information should be required to properly interpret the volumetric water content value of the soil. Moreover, soil with a high content of sand had a relatively narrow range of volumetric water contents for irrigation, thus reducing the accuracy of an FDR sensor measurement. In conclusion, analyzing soil water retention characteristics of the target soil and the soil-specific calibration would be necessary to properly quantify the soil water status and determine their adequate irrigation point using an FDR sensor.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.625-630
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• 1998

The conventional management which had economic requirement such as productivity, competition, customer satisfaction, and return needs the environmental management in order to meet a change of the external situation such as the environmental requirement (such as resources reduction, pollution prevention, and waste reduction). However, there have been a few studies which try to investigate internal factor and to regard external factors as negative ones. This paper proposes the external factors are significant to the performance. Several hypotheses were developed regarding the relationships. Based on the collected data from 126 firms, the hypotheses were analyed with SPSS.

• Journal of Welding and Joining
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• v.30 no.1
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• pp.72-77
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• 2012

Recently, according to the increase of income and development of quality of life, the leisure industry has been developed. In particular, the interest of design and manufacture technology of leisure yacht has significantly increased. However, domestic market of leisure ships is currently in its initiating stage. So research and development for structural strength of leisure yacht need to be investigated. In this study, lug of yacht's mast which is known for a critical damage region is explicitly considered. This paper deals with the estimation of stress concentration factors (SCFs) for lug of yacht's mast depending on dimensions of lug using hot spot stress. Also, SCF formulae is suggested using parametric study.

• Proceedings of The KACE
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• 2017.08a
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• pp.171-174
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• 2017

본 연구는 초등학교에서 로봇 활용 SW 교육을 실시하고 사전 수준 및 성별에 따라 효과에 차이가 있는지 규명하고자 하였다. 이를 위해 경기도의 A 초등학교 5, 6학년 학생 155명을 대상으로 로봇 활용 SW 교육을 실시하였으며, 수집된 자료는 대응 표본 t 검정, 일원분산분석, 공분산분석을 통해 평균의 차이를 분석하였다. 연구 결과, 로봇 활용 SW 교육을 실시한 후 학생들의 컴퓨팅사고력과 창의성이 유의하게 향상되었으나, 컴퓨팅사고력 수준이 상 집단인 학생들은 유의한 향상을 나타내지 않았다. 또한 학생들의 컴퓨팅사고력은 성별의 차이가 없었으나, 창의성은 성별에 따른 차이가 유의한 것으로 나타났다. 본 연구는 사전 수준과 성별에 따른 로봇 활용 SW 교육의 효과를 규명하여 로봇 활용 SW 교육에 대한 이해를 확장시켰다는 점에서 연구의 의의가 있다.

• Journal of Korean Library and Information Science Society
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• v.35 no.4
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• pp.317-338
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• 2004

This study intends to make a comprehensive inquiry about the present state of digital resources in Korean libraries Emphasis was on analyzing types and characteristics Of digital resources Which libraries have collected, and on surveying how both reasonable and systematic access to theses resources is provided To the end, this study examined 108 university libraries' retrieval mechanism and bibliographic records of digital resources. The result of this study is expected to be utilized in preparing the strategies to overcome the problems and limitations in organizing practices of digital resources.

• Korean Journal of Pharmacognosy
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• v.24 no.2
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• pp.124-130
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• 1993

Polysaccharide from Sanguisorba officinalis was separated and fractionated using DEAE-Sephadex ion-exchange chromatography and Sephacry HR-200 gel filtration chromatography. One of the fraction(Fr. II) was sulfated and its anticoagulant activity was tested in vitro. Sulfation could increase the clotting time 50 times compared to unsulfated one. Fr. II was hydrolyzed and its composition was analyzed by conjugation with 7-amino-1, 3-naphthalene disulfonic acid using HPLC and electrophoresis. Arabinose and galactose were mainly composed at the ratio of 4 : 1. In addition, xylose and rhamnose were also found.

• Electrical & Electronic Materials
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• v.3 no.1
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• pp.52-58
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• 1990

YBa$_{2}$ Cu$_{3}$O$_{7-{\delta}}$의 Ba대신 K를 일부 치환시킨 Y(Ba$_{1-x}$ , $K_{x}$ )$_{2}$Cu$_{3}$O$_{y}$ 에서 x의 값에 따른 초전도 특성의 변화를 연구하였다. XRD 무늬와 Infrared의 투과율로써 상의 변화를 관측하고 온도에 따른 전기저항의 변화를 측정함으로써 초전도성을 조사하였다. Ba 대신 K의 양이 증가할수록 Y(Ba$_{1-x}$ ,K$_{x}$)$_{2}$Cu$_{3}$O$_{y}$ 는 다중상이 되어 갔고 전기저항이 0이 되는 T$_{c}$는 점점 더 낮은 온도로 이동하다가 x.geq.0.6이 되면 초전도 특성을 잃었다.을 잃었다..

• 한국약용작물학회:학술대회논문집
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• 2011.04a
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• pp.100-101
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• 2011

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.629-637
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• 2000

Unbalance between user requirements and insufficient network resources makes a congestion. In the future since the communication networks will have very heavy traffic congestion will be more serious. The ATM networks was recommended to support the B-ISDN service for the future multimedia communication. In thie sense of congestion avoidance and recovery the ABR service category in ATM networks allows the feedback flow control mechanism to dynamically allocate the idle bandwidth of the network to users fairly and to control the network congestion rapidly In this paper we introduce a congestion control scheme using systematical approach to confirm robust stability with respect to unknown round trip delay for the network which has both unicast and multicast connections.