• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.1
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• pp.28-33
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• 2013

Spin-torque oscillators (STO) is a new device that can be used as a tunable microwave source in various wireless devices. Spin-transfer torque effect in magnetic multilayered nanostructure can induce precession of magnetization when bias current and external magnetic field are properly applied, and a microwave signal is generated from that precession. We proposed a semi-empirical circuit-level model of an STO in previous work. In this paper, we present a refined STO model which gives more accuracy by considering physical phenomena in the calculation of effective field. Characteristics of the STO are expressed as functions of external magnetic field and bias current in Verilog-A HDL such that they can be simulated with circuit-level simulators such as Hspice. The simulation results are in good agreement with the experimental data.

• Journal of Aerospace System Engineering
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• v.8 no.4
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• pp.18-23
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• 2014

In preliminary design phase, the wing geometry of the civil aircraft was determined using the empirical equation and historical data. To make wing geometry more aerodynamically efficient, an aerodynamic shape optimization was conducted. For this purpose the parametric modeling, high fidelity CFD analysis and metamodel-based optimal design technique were adopted. The parametric modeling got the design process to achieve the improvement by generating the configuration outputs easily for the major design variables. The optimal design equations were formularized as the type of the multi-objective functions considering low/high speed and lift/drag coefficient. The optimal solution was explored with the help of the kriging metamodel and the desirability function, therefore the optimal wing planform was sought to be excellent at both low and high speed region. Additionally the optimal wing planform was validated that it was excellent not only at the specific AOA, but also all over the range of AOA.

• KDI Journal of Economic Policy
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• v.42 no.2
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• pp.57-84
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• 2020

This study analyzes global inflation synchronization and derives policy implications for the Korean economy. Unlike previous studies that assume a single global inflation factor, this study investigates if inflation in Korea can be explained further by other global inflation factors. Our principal component analysis provides three principal components for global inflation that are linked to the Korea inflation rate - the first component is closely related to OECD inflation, and the second and third components reflect China's inflation. This study empirically demonstrates via in-sample fitting and out-of-sample forecasting that the three principal components of global inflation play a significant role in explaining and predicting Korean inflation in the short-term, while their role is limited in the mid-term. Domestic macroeconomic variables are found to be more important for the mid-term movements of the Korean inflation rate. The empirical results here suggest that the Bank of Korea should focus more on domestic economic conditions than on global inflation when implementing monetary policy because global factors are likely to be already reflected in domestic macro-variables in the mid-term.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.22-23
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• 2014

멀티미디어 응용을 비롯한 스트리밍 응용들에서는 메모리와 CPU 사이의 데이터 전송이 상당한 비율의 에너지 소모를 차지한다. 데이터 재사용 분석은 이러한 응용 프로그램 에서 빈번히 사용되는 데이터를 고속의 저전력 메모리에 복사하도록 하여 에너지 소비를 줄일 수 있는 기회를 제공한다. 본 연구에서는 데이터의 재사용 분석을 통하여 프로그램이 최적화되도록 자동화된 기법을 제안하고 있다. 제안하는 기법을 사용할 경우 메인 메모리만 사용하는 경우에 비하여 절반 정도의 에너지 소비를 줄일 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1340-1343
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• 2012

정보의 시각화는 추상적 정보를 직관적으로 이해하기 쉽도록 시각적으로 명확하게 표현하는 방법을 말한다. 대용량의 바이오 데이터를 다루는 생물정보학(bioinformatics) 분야에서는 컴퓨터의 높은 성능을 활용하여 수많은 유전학적 데이터들을 분석하고 있다. 다양한 생물정보학 실험에서 전사체는 특정한 조건에서 발현된 RNA의 총합을 말한다. 분석된 전사체 정보는 텍스트형태로 제공이 되는데 이를 사용자가 수작업으로 비교하는 데에는 한계가 있다. 따라서 분석된 전사체 정보를 효과적으로 인지할 수 있도록 시각화하는 연구들이 진행되고 있다. 본 논문에서는 그래프 라이브러리인 yFile을 활용하여 추정된 전사체를 실시간으로 시각화하여 제공하는 방법을 제안한다. GTF파일을 입력받아서 데이터베이스에 저장하고 이 정보를 이용하여 그래프를 생성한다. 실험 결과는 전사체를 시각화 하는 방법을 통하여 다양한 전사체 정보를 알아 낼 수 있고, 최종적으로는 novel gene을 찾는 것이 가능할 것으로 기대한다.

• Korean journal of applied entomology
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• v.60 no.2
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• pp.235-239
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• 2021

In this study, one newly recorded species, P. vittapenna Kim & Park, of the Promalactis is recognized. A diagnosis and distributional data are provided with illustrations of its adult and genitalia. A taxonomic key to all Laos Promalactis species is also provided.

• BMB Reports
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• v.51 no.12
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• pp.611-612
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• 2018

$C1q/TNF-{\alpha}-Related$ Protein 1 (CTRP1) has recently been shown to act as a blood pressure regulator, as it induces vasoconstriction. In the aorta, CTRP1 facilitates recruitment of angiotensin II receptor 1 (AT1R) to plasma membrane, through activation of the AKT/AS160 signaling pathway. This leads to activation of the Ras homolog gene family (Rho)/Rho kinase (ROCK) signaling pathway, resulting in vasoconstriction. Accordingly, mice overexpressing Ctrp1 have hypertensive phenotype. Patients with hypertension also display higher circulating CTRP1 levels, compared to healthy individuals, indicating that excessive CTRP1 may affect development of hypertension. Conversely, CTRP1 is regarded as an 'innate blood pressure modulator' because CTRP1 increases blood pressure under dehydration to prevent hypotension. Mice lacking Ctrp1 fail to maintain normotension under dehydration conditions, resulting in hypotension, suggesting that CTRP1 is an essential protein for maintaining blood pressure homeostasis. In conclusion, CTRP1 is a novel, anti-hypotensive vasoconstrictor that increases blood pressure during dehydration-induced hypotension.

• Journal of the Korean Institute of Plant Engineering
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• v.23 no.4
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• pp.57-64
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• 2018

User-based collaborative filtering is a method of recommending an item to a user based on the preference of the neighbor users who have similar purchasing history to the target user. User-based collaborative filtering is based on the fact that users are strongly influenced by the opinions of other users with similar interests. Item-based collaborative filtering is a method of recommending an item by comparing the similarity of the user's previously preferred items. In this study, we create a recommendation model using user-based collaborative filtering and item-based collaborative filtering with consumer's consumption data. Collaborative filtering is performed by using RFM (recency, frequency, and monetary) technique with purchasing data to recommend items with high purchase potential. We compared the performance of the recommendation system with the purchase amount and the performance when applying the RFM method. The performance of recommendation system using RFM technique is better.

• Journal of Ceramic Processing Research
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• v.19 no.6
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• pp.525-529
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• 2018

The antireflective (AR) coated poly methyl methacrylate (PMMA) substrate was deposited by atomic layer deposition (ALD) on a self-assembled monolayer (SAM) to improve hydrophobicity and mechano-chemical properties of organic thin films. The water contact angles (WCA) were tested to characterize the surface wettability of SAM octadecyltrichlorosilane (OTS) films. Results showed that a contact angle of $105.9^{\circ}$ was obtained for the SAM films with an annealing process, and the highest WCA of $120^{\circ}$ was achieved for the films prepared by the SAM and ALD multi-process. The surface morphology of the SAM films with different assembly times and varying number of ALD cycles was obtained by atomic force microscopy (AFM). The maximum light transmittance for the SAM films on the PMMA substrate reached 99.9% at a wavelength of 450 nm. It was found that the SAM surfaces were not affected at all by the ALD process.

• Journal of Contemporary Eastern Asia
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• v.19 no.2
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• pp.216-233
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• 2020

Over the last 70 years, South Korea has gone through countless provocations from North Korea. Provocation is something that must be delicately calculated before the actual action, since it can be extended to a serious conflict. Among the possible factors, this paper focuses on the leader's characteristic, because 1) under North Korean dictatorship, the leader's thoughts are critical influence to policies and 2) personal characteristic, especially if it is the dictator's, hardly changes even when the external circumstances change. The purpose of this paper is in analyzing the correlations between North Korean leader's characteristics and provocation pattern. First, three generations of Kim Il-sung, Kim Jong-il, and Kim Jong-un's personal characteristics will be described. Next, particular provocation features in respective leader's period will follow. Lastly, how each leader's characteristic and concerns were reflected on the provocations will be analyzed.