• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.111-118
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• 2014

Current friend recommendation system on Twitter primarily recommends the most influential twitter. However, this way of recommendation has drawbacks where it does not recommend the users of which attributes of interests are similar to theirs. Since users want other users of which attributes are similar, this study implements follower recommendation system based on the similarity of twitter node informations. The data in this study is from SNAP(Stanford Network Analysis Platform), and it consists of twitter node information of which number of followers is over 10,000 and twitter link information. We used the SNAP data as a training data, and generated a classifier which recommends and predicts the relation between followers. We evaluated the classifier by 10-Fold Cross validation. Once two twitter node informations are given, our model can recommend the relationship of the two twitters as one of following such as: FoFo(Follower Follower), FoFr(Follower Friend), NC(Not Connected).

• The Transactions of the Korea Information Processing Society
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• v.1 no.1
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• pp.81-91
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• 1994

A DCT map and new cldebook design algorithm based on a two-dimension discrete cosine transform (2D-DCT) is presented for coder of image vector quantizer. We divide the image into smaller subblocks, then, using 2D DCT, separate it into blocks which are hard to code but it bears most of the visual information and easy to code but little visual information, and DCT map is made. According to this map, the significant features of training image are extracted by using the 2D DCT. A codebook is generated by partitioning the training set into a binary tree based on tree-structure. Each training vector at a nonterminal node of the binary tree is directed to one of the two descendants by comparing a single feature associated with that node to a threshold. Compared with the pairwise neighbor (PPN) and classified VQ(CVQ) algorithm, about 'Lenna' and 'Boat' image, the new algorithm results in a reduction in computation time and shows better picture quality with 0.45 dB and 0.33dB differences as to PNN, 0.05dB and 0.1dB differences as to CVQ respectively.

• Journal of the Korean Magnetics Society
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• v.22 no.2
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• pp.66-72
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• 2012

The findings of ferromagnetic superconductor have attracted much attention not only for fundamental research to investigate how the antagonistic properties of ferromagnetism and superconductivity coexist peacefully but also for potential technological applications. Firstly, in order to help for understanding the ferromagnetic superconductor, I have explained the orbital and paramagnetic pair-breaking effects of magnetic field, which breaks the superconducting Cooper pairs. In addition to such effects of magnetic field, the singlet Cooper pairs become unstable upon going through the ferromagnetic materials by the proximity effect. The proximity effect occurs at the interface of thin films composing of superconductor and ferromagnet and leads to have very short penetration depth of Cooper pairs. However, a type of odd-frequency triplet in comparison with the singlet could be very stable and has a longer effective depth. It needs to be explored for the innovative spintronic devices. Finally, various ferromagnetic superconductors coexist and the lower-dimensional materials under the Quantum confinement effect have been introduced.

• Korean Journal of Optics and Photonics
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• v.33 no.1
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• pp.22-27
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• 2022

We fabricate a polarization-independent dielectric multilayer thin-film diffraction grating for a spectral-beam-combining (SBC) system with a simple grating structure and low aspect ratio. Due to the refractive index and thickness error of the manufactured thin films, the diffraction efficiency of the fabricated diffraction grating was lower than that of the design. The causes of the errors were analyzed, and it was confirmed through simulation that diffraction efficiency could be compensated through an additional coating on the manufactured diffraction grating. As a result of sputtering an additional Ta₂O₅ layer on a fabricated diffraction grating, the diffraction efficiency was corrected and a maximum 91.7% of polarization-independent diffraction efficiency was obtained.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.434-440
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• 2023

This paper propose the method that measure the main system parameters for current control of a.c. motor adopting the vector control technique. The automatical method that tuning PI control gains for current control of servo motors are used frequently through the information of main system parameters, wire resistance and inductance. In this study, the techniques to measure these two system parameters through the control of 3-phase inverter are presented. These control and measuring method are implemented by measuring output phase current obtained as a results of the step current control using simple proportional feedback input. Moreover, this method use freewheeling current of inverter at special switching mode for measuring inductance. This analytic strategy is could measure and calculate the system parameters without the complex measurement algorithm and new additional measuring circuits. That is could measure the total resistance and total inductance including wiring resistance and conduction resistance of switching devices using real driving circuits to control the motors.

• Neonatal Medicine
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• v.17 no.2
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• pp.193-200
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• 2010

Purpose: Feeding desaturation is a common problem among preterm infants which can result in prolonged hospital stays, longterm feeding difficulties and growth delay. The purpose of this study was to identify the characteristics of premature infants with feeding desaturation and to examine the effect of orocutaneous stimulation on oral feeding. Methods: During the first phase of this study, 125 extremely low birth weight infants were reviewed retrospectively. Characteristics between infants with feeding desaturation (n=34) and those without feeding desaturation (n=91) were examined. During the second phase, 29 infants recruited from March, 2009 to May, 2010 were subjected to orocutaneous stimulation. The results of orocutaneous stimulation were compared to a control group (n=81). Results: The first phase of the study revealed that extremely low birth weight infants with feeding desaturation were significantly lower in gestational ages at birth, and had lower 5 minute apgar scores, more gastroesophageal refluxes and bronchopulmonary dysplasia. Infants without feeding desaturation reached full enteral feeding significantly earlier and showed shorter duration of hospital stay. At the second phase, infants in the intervention group showed shorter days to achieve initiation of bottle feeding, shorter days in achievement of full bottle feeding, last episodes of feeding desaturation and length of hospital stay compared to the control group of similar characteristics. Conclusion: Orocutaneous stimulation among extremely low birth weight infants results in earlier achievement of full bottle feedings without episodes of feeding desaturation hence shortens the length of hospital stay.

• Korean Journal of Heritage: History & Science
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• v.49 no.1
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• pp.68-83
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• 2016

Pan-jang(板墻) has become the lost facility, and the examples of its original form can be found no more due to its variable material characteristics. In order to study panjang as a lost facility, the following are needed: - To bring to light its usage and examples. - To investigate its components and structure. Panjang refers to the wall made of wooden plate and is classified as a special wall according to its material characteristics. In addition, Chinese mokyeongbyuk(木影壁) and Japanese panbyeong(板?) are similar to Korean panjang in terms of the materials, but there are clear differences in their structures. Panjang was also transformed into various types according to their materials or forms. As the wooden elements of panjang, sinbang(信防), pillars, do-ri(道里), jungbang(中枋), inbang(引枋), parn(板), dae(帶), choyeop(草葉), bangyeon(方椽), gaeparn(蓋板), pyeonggodae(平高臺), and yeonharm(椽檻) were selectively used, and they are similar, in particular, to the components of ilgakmoon(一角門). The stylobate of panjang is largely classified into three according to the kinds and structures of the wooden elements; and its frame into two according to whether sanginbang(上引枋) is used or not. The materials for the roof area include planks(蓋板) and tiles and have the distinct structural differences according to each material.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.4
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• pp.438-457
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• 2019

The main purpose of this paper is to identify the entry types and locational determinants of North Korean workers in cross-border regions between North Korea and China. More specifically, the paper has attempted to divide the entry type of them in the regions into two; 1) entry via transactions between Chinese traders with North Korea and North Korea trade companies, and 2) entry via transactions between Korean-Chinese middlemen and North Korean trade companies. Also, it has analyzed main factors of their locational determinants in the spatial contexts of the regions. There have been changes in two perspectives in terms of the entry paths and types of them in accordance with the transformation of characteristics of United Nations sanction against North Korea from 'call-upon' to 'decide' after UN Security Council Resolution 2094 in 2013. Firstly, main agents who have dealing with North Korean trade companies which have right to dispatch North Korean workers have been changed from Chinese traders into Korean-Chinese brokers who are specialized in the introduction of North Korean workers with one-stop service from visa administrative to labor managements. Secondly, there has been a transfer of North Korean workers in the regions from formal to informal workers who has been admitted into China with a short stay or a tourist visa, and then remained illegally to be employed in China. Therefore, as demands on service which is able to guarantee the security of North Korean informal workers and their managements have increased, Korean-Chinese brokers have been stimulated in the regions after the operation of real international sanctions against overseas North Korean workers. In addition, the main factors of their locational determinants in cross-border regions between North Korea and China are could be analyzed in three perspectives; 1) an increase in real wages in accordance with the reform of the Chinese social insurance system after 2011, 2) the structural vulnerability of labor markets in the regions, 3) the utilization of stable and manageable workers.

• Proceedings of the Technology Innovation Conference
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• 2003.06a
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• pp.116-135
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• 2003

우리나라는 최근에 IMF 에 재정적 지원을 요청하는 상황이 계기가 되어 국가경쟁력과 삶의 질 측면에 상당한 관심을 가지게 되었다. 이러한 환경변화는 사회저변에 효율성을 강조하는 풍토를 확산시키고, 위기상황의 재발방지를 위해 그 원인을 분석하고 대안을 마련하는 등 사회 전반적으로 각고의 노력을 촉발시키게 하는 계기가 되었다. 이러한 논의들 중에 눈에 띄는 한가지는 과학과 기술사이의 관계에 관한 논쟁인데, 최근에 활발히 논의되고 있는 과학과 기술사이의 연계는 미국을 중심으로 많은 연구가 진행되고 있으며, 이러한 연구들은 대체적으로 과학과 기술사이에는 상당한 정도의 상관관계가 있고, 이 둘 사이는 서로 상호작용하면서 경제성장을 이끄는 역할을 한다고 주장하고 있다. 본 연구에서는 이러한 논의들을 국내에 적용시킴으로써 해외의 사례가 우리에게 시사점이 될 수 있는지 체계적으로 분석하려고 시도하였다. 과학과 기술사이의 연관성을 알아보기 위하여, 과학의 연구성과를 대변하는 대용치로 SCI논문을 사용하였고, 이러한 연구성과가 얼마만큼 사회에 파급되어 산업화 또는 상업화되었는지를 측정하기 위해 특허출원수를 추출하여, 연구의 목적에 맞게 modify 하는 과정을 거쳤으며, 추세분석과, 상관관계분석 그리고 회귀분석을 실시하였다. 본 연구는 실증분석을 통하여, 과학과 기술사이에는 일부 소수의 영역을 제외하고 매우 높은 상관관계가 있음을 발견하였고, 우리나라의 주력산업이었던 기계분야의 쇠퇴를 실증적으로 확인 할 수 있었으며, 정부의 적극적인 지원아래 폭발적으로 성장하였던 IT분야의 증가추세를 확인할 수 있었다. 따라서 본 연구에서는 국가경쟁력의 근간이 되는 연구개발부문에 경제논리를 배제하는 지속적인 투자를 제언함으로써, 국가경쟁력 제고와 삶의 질 향상이라는 두 마리 토끼를 잡을 수 있는 방안은 과학과 기술의 유기적인 연계에 있음을 밝히고 있다. 건설을 위한 정책적 시사점과 동북아 연구개발정보 Portal 및 APEC APGrid 연구망 등의 구체적인 정보인프라 구축방안을 도출하였다.술 주기를 도출하고, 산업 내 평균 권리 청구 항목 수를 이용하여 각 산업의 기술 범위를 비교하였다. 각각의 동적 분석을 통해 시간에 따른 변화 양상이 관찰하였고, ANOVA 분석을 이용하여 통계적 유의성을 검증하였다. 본 연구는 현재의 기술 패러다임 내에서 Pavitt이 제시한 산업 분류의 근거를 보충 설명하였고 특허 정보를 이용하여 기술혁신의 산업별 유형에 대한 폭넓은 분석방법을 제시하였다.별 시간대별 효과분석을 통하여 정책의 시행여부가 결정되어야 할 것이다. 한편, 화물전용차선의 설치로 인한 물류비용의 절감을 보다 효과적으로 달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that

• Journal of Wetlands Research
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• v.6 no.1
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• pp.57-72
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• 2004

Macrobenthic fauna were studied on a tidal flat in Garolim Bay in July 2002, in order to understand their spatial distribution with the surface sediment types. Forty-nine stations were set on the tidal flat. A total of 147 species was sampled with the mean density of $1,140ind./m^2$ and the mean biomass of $157.2g/m^2$. The polychaetes were speices- and density-dominant faunal group with 64 species and the mean density of $791ind./m^2$. Mollusks were biomass-dominant faunal group with $132.0g/m^2$. Major dominant species were two polychaetes, Mediomastus californiensis with the mean density of $374ind./m^2$ and Heteromastus filiformis with $224ind./m^2$. Also mollusks such as Umbonium thomasi, Batillaria cumingi and Ruditapes philippinarum was relatively high in the mean density, showing the density of 45, 42, $32ind./m^2$ respectively. Especially, U. thomas was distributed in the mouth of the bay, where sediment grain size is rather coarse, and R. philippinarum at near tidal channel. Based on the cluster analysis, the macrobenthic community on the tidal flat was classified into seven station groups depending on the benthic environmental parameters(sediment types). Compared with other Korean tidal flats, species richness of Garolim tidal flats is more and less low.