• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.301-306
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• 2004

In this study, Dual servo mechanism with VCM(Voice Coil Motor) and PZT is designed for a high precision force and position control. We designed the VCM actuator and dual servo mechanism with leaf spring. VCM actuators, with their high linearity, simple structure, low weight, and high efficiency, are increasingly being used in micro-positioning applications. There are many kinds of VCM with a structure. VCM actuators are divided into two types by moving parts. One is moving magnet type and the other moving coil type. We described the properties of these two types of VCM. Design parameters of VCM are defined through the FEM simulation analysis of magnetic field and dynamic model of dual servo mechanism. These researches help to for decreasing loss in the air gap of VCM. We present dual servo mechanism is effective mechanism for a force control in hi h precision, properties of designed VCM.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.84-87
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• 2005

The citrus industry represents a major sector of agribusiness in Jeju successfully nurtured by the local governmental farm bureaus for the past three decades. However, in the face of increasing imports effected under the international free trade agreement, the continuous economic viability of the island’s citrus industry is no longer assured. Thus, it entails exploration and development of new agribusiness potentials that are supplemental and/or alternative to the citrus industry. In this presentation, I will discuss two projects of such potentials. (i) Under the tripartite collaboration among Kumho Life and Environmental Science Laboratory, Cheju National University and South Jeju County, genetically engineered turfgrass cultivars possessing both herbicide- and shade-tolerances (gene pyramiding) are currently at final phase of phenotype evaluations and environmental safety assessments. (ii) Fig fruits with longer shelf-life are being developed with support from Jeju HiTech Industrial Development Institute (HiDI) and at its initial phase of development.

• Genomics & Informatics
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• v.17 no.3
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• pp.32.1-32.6
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• 2019

Currently, Illumina sequencers are the globally leading sequencing platform in the next-generation sequencing market. Recently, MGI Tech launched a series of new sequencers, including the MGISEQ-2000, which promise to deliver high-quality sequencing data faster and at lower prices than Illumina's sequencers. In this study, we compared the performance of two major sequencers (MGISEQ-2000 and HiSeq 4000) to test whether the MGISEQ-2000 sequencer delivers high-quality sequence data as suggested. We performed RNA sequencing of four human colon cancer samples with the two platforms, and compared the sequencing quality and expression values. The data produced from the MGISEQ-2000 and HiSeq 4000 showed high concordance, with Pearson correlation coefficients ranging from 0.98 to 0.99. Various quality control (QC) analyses showed that the MGISEQ-2000 data fulfilled the required QC measures. Our study suggests that the performance of the MGISEQ-2000 is comparable to that of the HiSeq 4000 and that the MGISEQ-2000 can be a useful platform for sequencing.

• Land and Housing Review
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• v.6 no.2
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• pp.101-106
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• 2015

In order to minimize regional disparities between the North and the South, it is very important to reduce shortages of food and energy in North Korea in the short and mid-term. In the long term, it is important to reduce not only regional disparities between two Koreas but also regional disparities in North Korea. It is important to consider national policies of the North, the South and other countries in Northeast Asia in the process of building regional development policies for North Korea because the future of regional development in North Korea depends on policies of stakeholder in Northeast Asia. This study suggest some policy directions for regional development in North Korea. At first, building new industries, such as hi-tech industries and MICE, is important for regional development potentials in North Korea. Also, we should take some special development strategies according to regional potentials in North Korea. For example, Nampo region should be specialized through hi-tech industries. Wonsan region should be specialized through MICE. Finally, this study suggests some policy issues to the South Korean government. Financial support from South Korean government about inter-Korean economic cooperation should have priorities on the regions where have potentials of hi-tech industries and MICE. Also, we should implement inter-Korean economic cooperation policies under consideration about spatial aspects.

• Wind and Structures
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• v.23 no.6
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• pp.559-575
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• 2016

In order to investigate the influence of different blade positions on aerodynamic load and wind loads and load-effects of large scale wind turbine tower under the halt state, we take a certain 3 MW large scale horizontal axis three-blade wind turbine as the example for analysis. First of all, numerical simulation was conducted for wind turbine flow field and aerodynamic characteristics under different halt states (8 calculating conditions in total) based on LES (large eddy simulation) method. The influence of different halt states on the average and fluctuating wind pressure coefficients of turbine tower surface, total lift force and resistance coefficient, circular flow and wake flow characteristics was compared and analysed. Then on this basis, the time-domain analysis of wind loads and load-effects was performed for the wind turbine tower structure under different halt states by making use of the finite element method. The main conclusions of this paper are as follows: The halt positions of wind blade could have a big impact on tower circular flow and aerodynamic distribution, in which Condition 5 is the most unfavourable while Condition 1 is the most beneficial condition. The wind loads and load-effects of disturbed region of tower is obviously affected by different halt positions of wind blades, especially the large fluctuating displacement mean square deviation at both windward and leeward sides, among which the maximum response occurs in $350^{\circ}$ to the tower top under Condition 8; the maximum bending moment of tower bottom occurs in $330^{\circ}$ under Condition 2. The extreme displacement of blade top all exceeds 2.5 m under Condition 5, and the maximum value of windward displacement response for the tip of Blade 3 under Condition 8 could reach 3.35 m. All these results indicate that the influence of halt positions of different blades should be taken into consideration carefully when making wind-resistance design for large scale wind turbine tower.

• Resources Recycling
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• v.23 no.2
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• pp.53-60
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• 2014

In order to separate Indium and Tin from spent indium tin oxide (ITO) sludge, direct hydrochloric acid leaching and thermal reduction followed by HCl leaching were applied. In case of direct leaching of spent ITO, leaching rate of In and Sn was 18.5% and 19.95%, respectively. Whereas, in case of thermal hydrogen treatment of ITO sludge at different temperatures such as $700^{\circ}C$, $800^{\circ}C$, $900^{\circ}C$ and $1100^{\circ}C$, followed by HCl leaching, we obtained the result of more than 97% leaching rate of Sn. Specially, thermal treatment at $800^{\circ}C$ showed the highest leaching rate of 98.2% of Sn. Precipitation method was used for separation and recovery of Sn from leached mixed solution. If the solution pH were adjusted 2.0, 99.69% of Sn precipitated and 10.3% of In was precipitated. This confirmed the possibility of separation of Sn and In from leached solution by precipitation method.

• Resources Recycling
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• v.24 no.2
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• pp.62-68
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• 2015

The high pure tin production was conducted from crude-tin containing waste solder by electro-refining process. The electro-refining process maintained at 0.2V produced tin with purity of 99.98%, whereas a little increase of voltage to 0.3 V resulted tin purity of 99.92%. The high pure tin of 3N in the present process was produced by fixing the voltage at 0.3V. Considering the high pure tin production, the current density was maintained within $100-120A/m^2$ with current efficiency of 94%. Addition of sulfuric acid of 20 ~ 25 g/L to the electrolyte solution was performed in order to keep Pb (lead) concentration below 100 mg/L in the final tin product. The anode slime generated during electro refining process was analyzed by X-ray diffraction (XRD) study to understand the phases of impurities in it. It detected the presence of Cu and Ag in the slime as in the form of $Cu_6Sn_5$, $Ag_3Sn$, whereas Pb occurred as $PbSO_4$ compound.

• Journal of The Korean Association of Information Education
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• v.1 no.2
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• pp.84-100
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• 1997

All technology has both intended and unintended effects, we have said, and information technology is no exception. Information technology offers a number of challenges: those of computer education, computer literacy, the ethical and societal impacts of computing and communication systems. Current computer education focuses primarily on the history, parts and usage of a computer, and programming, it does not fully include the moral standards or ethics that help guide behavior and conduct for citizens of Information society. The purpose of this study is to review of the theoretical issues and societal impacts of computers, communication systems and computer ethics; then, to nalyse current curriculum and content of school computer education in Korea: finally, to develop a possible course in computer ethics containing a goal statement and aspects of computer literacy. Contents in computer ethics covers issues of nettiquette, privacy, health, copyright-related software and network piracy, computer crime and viruses. Six suggestions are made for the computer ethics of Information Age in the conclusion.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.496-499
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• 1995

Amorphous $Co_{80+x}TM_{12}B_{8-x}$ (TM = Ti, Zr, Hf, Nb and x = 0, 2, 4 at%) alloys were prepared by single roll melt spinning technique. Saturation magnetization of the amorphous ribbons was measured by SQUID and vibrating sample magnetometer from 5 to 800 K under applied fields up to 10 kOe. Typical thermo-magnetization curves were observed and the average values of the spectroscopic splitting g factor were estimated from the ferromagnetic resonance curve. For all the amorphous alloys studied here the saturation magnetization in the temperature range 5 K up to about $0.3T_{c}$ can be described by the Bloch relation: $M_{s}(T)\;=\;M_{s}(0)(1-BT^{3/2}-CT^{5/2})$. From the values of $M_{s}(0)$, B and spectroscopic splitting g factor the spin wave stiffness constants were calculated.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.278-282
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• 1990

In this paper, two different plusewidth modulation(PWM) for inverter and voltage control technique are described. Inverter output harmonics are harmful in induction motor drive because it lead to ripple torque and induction interference. In order to reduce or minimize losses, various forms of PWM strategy such as PM(Positive Modulation) and NM(Negative Modulation) are discussed.