• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.9-12
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• 2008

PSC-I거더형태는 교량설계에 있어 널리 쓰이는 형태이다. 현재 일부 선진국가들은 고강도콘크리트를 교량에 적용하고 있는 반면 국내에는 다소 낮은 강도의 콘크리트(40MPa)를 사용하고 있다. 이에 따라 본 논문은 고강도 콘크리트를 실용화하기 위해 고강도 콘크리트를 타설한 부재의 특성과 거동에 대해 연구하였다. 이를 위해 4개의 거더를 제작하여 부재의 성능과 구조적 거동을 분석하였다. 실험에 앞서 상용프로그램을 이용하여 예상되는 거동을 구조해석을 통해 알아보았다. 스틸 게이지와 콘크리트 게이지를 매립하여 철근과 콘크리트의 종방향, 횡방향 변형율을 측정하였고. LVDT(Linear Variable Differential Transducer)을 중앙부와 지점에 설치해 부재의 처짐 및 변형을 측정하였다. 긴장작업시와 구조실험간 하중-처짐 관계와 균열하중의 실험결과를 구조해석 결과와 비교 분석하였다. 이를 통해 고강도 콘크리트를 부재에 적용하였을 때 거동변화와 긍정적인 효과에 대해 알아보았다.

• 아태비즈니스연구
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• 제11권2호
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• pp.159-172
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• 2020

Purpose - The purpose of this study is to investigate economic variables which have impact on the prices and returns of preferred stocks and to provide investors, underwriters, and policy makers with information regarding correlations and causal relations between them. Design/methodology/approach - This study collected 98 monthly data from Korea Exchange and Bank of Korea. The Granger causal relation analysis, unit-root test and the multiple regression analysis were hired in order to analyze the data. Findings - First, our study derives the economic variables affecting the prices and returns of preferred stocks and their implications, while previous studies focused mainly on the differential characteristics and related economic factors between common and preferred stocks. Empirical results show that the significant variables influencing the prices and returns of preffered stocks are consumer sentiment index, consumer price index, industrial production index, KOSPI volatility index, and exchange rate between Korean won and US dollar. Second, consumer sentiment index, consumer price index, and industrial production index have significant casual relations with the returns of preferred stocks, providing market participants with important information regarding investment in preferred stocks. Research implications or Originality - This study is different from previous studies in that preferred stocks themselves are investigated rather than the gap between common stocks and preferred stocks. In addition, we derive the major macro variables affecting the prices and returns of preferred stocks and find some useful causal relations between the macro variables and returns of preferred stocks. These findings give important implications to market participants, including stock investors, underwriters, and policy makers.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.129-129
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• 2010

The conjugated oligomers with rigid and fused-ring structures are of interest for the solution-processable organic thin film transistors (OTFTs) due to their well defined structure and high purity. In this study, alkyl substituted benzothiophene based oligomers were synthesized by a novel route, the key point of which is the acid-induced intermolecular cyclization reaction of aromatic methyl sulfoxides, and were confirmed by $^1H$-NMR and FT-IR studies. The obtained oligomers showed the good solubility in common organic solvents such as hexane, chloroform, and dimethylchloride at room-temperature, which is due to the introduced alkyl chain. The physical and optical properties of the oligomers were studied using differential scanning scalorimetry (DSC), cyclic-voltammetry (CV), UV-visible and PL spectra studies. Solution processed OTFT device based on synthesized oligomers show a high hole mobility of up to $0.01\;cm^2V^{-1}s^{-1}$, $I_{on}/I_{off}$ of $10^5$ and threshold voltage of -14V.

• 산업경영시스템학회지
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• 제30권4호
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• pp.13-20
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• 2007

The aim of this study was to investigate effects of odor intensity on the olfactory sensibility and sensibility structure. Three odor samples(B, C, and D) of T&T olfactometer were selected by the preference rank : the lowest preference(C) ; the moderate one(B) ; and the highest one(D). Three levels(-1, +1, and +3) of odor intensity at each sample were presented to 50 subjects(25 female, 25 male), and the olfactory sensibility was rated by using semantic differential scale composed 25 sensibility characteristics. At each sample, the olfactory sensibility was significantly affected by the odor intensity. Moreover, the structure of olfactory sensibility was influenced by the odor intensity. However, two sensibility factors such as 'aesthetics' and 'intensity' were common factors, whereas 'mildness', 'complexity', and 'activity' were unique factors with odor intensity. In conclusion, the olfactory sensibility was significantly affected by the odor intensity and the odor preference.

• 한국미생물·생명공학회지
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• 제14권2호
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• pp.205-208
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• 1986

Bacillus thuringiensis 균주중 23 serovars의 생화학적 특성을 비교 연구하였다. 23개의 혈청성 균주는 모두 그람염색에 양성반응을 나타냈고, 내독소와 아포를 형성하며, KIA배지에서 산과 알칼리를 생산하고, 포도당배지에서 깨스를 생산하며, 전분을 가수분해하고, nitrate을 환원하나, H$_2$S 와 indole을 생산하지 않았고, 또한 lysine, ornithine, phenylalanine, malonate, lactose, dulcitol, adonitol, inositol, sorbitol, arabinose, raffinose, rhamnose, maltose, xylose을 분해치 않고, oridase를 생산하지 않았다. 18 serovars는 MR 검사에서 양성 이였고, 15 serovars는 VP검사에서 양성이였다. 4 serovars 는 citrate을 이용했다. 5 serovars는 포도당 배지에서 산을, 2 serovars는 DNase를, 15 serovars는 lecithinase를 생산했다. 12 serovars는 arginine을, 11 serovars는 sucrose를, 2 serovars는 manitol을, 9 serovars는 salicin을 분해했다. serovar tochigiensis만이 hemolysis를 하지 않았다.

• Journal of Power Electronics
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• 제10권4호
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• pp.342-350
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• 2010

Randomizing the switching frequency (RSF) to reduce the electromagnetic interference (EMI) of switching power converters is a well-known technique that has been previously discussed. The randomized pulse position (RPP) technique, in which the switching frequency is kept fixed while the pulse position (the delay from the starting of the switching cycle to the turn-on instant within the cycle) is randomized, has been previously addressed in the literature for the same purpose. This paper presents a double-hybrid technique (DHB) for EMI reduction in dc-dc switching regulators. The proposed technique employed both the RSF and the RPP techniques. To effectively spread the conducted-noise frequency spectrum and at the same time attain a satisfactory output voltage quality, two parameters (switching frequency and pulse position) were randomized, and a third parameter (the duty ratio) was controlled by a digital compensator. Implementation was achieved using field programmable gate array (FPGA) technology, which is increasingly being adopted in industrial electronic applications. To evaluate the contribution of the proposed DHB technique, investigations were carried out for each basic PWM, RPP, RSF, and DHB technique. Then a comparison was made of the performances achieved. The experimentally investigated features include the effect of each technique on the common-mode, differential-mode, and total conducted-noise characteristics, and their influence on the converter’s output ripple voltage.

• 대한유전성대사질환학회지
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• 제14권1호
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• pp.48-53
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• 2014

Smith-Lemli-Opitz syndrome (SLO) is a rare, autosomal recessive disease caused by an inborn error in cholesterol synthesis. Patients with this disease suffer from multiple malformations due to reduced activity of 7-dehydrocholesterol reductase (DHCR7), which increases 7-dehydrocholesterol (7DHC) and 8-dehydrocholesterol (8DHC) concentrations and decreases cholesterol concentration in body fluids and tissue. Here, we describe Korean siblings with SLO who were diagnosed recently, and performed a review of literature about Korean cases with SLO to date. Microcephaly and syndactyly of the second and third toes are the most common physical finding in SLOS patients. Other malformations including growth failure, cleft palate or bifid uvula, various heart malformation, genital ambiguity in males are also accompanied. Not all patients showed low levels of serum cholesterol, so DHCR7 mutation analysis can be helpful to confirmative diagnosis. Two mutations on p.R352 locus (p.R352W and p.R352Q) are commonly identified in Korean SLO patients. Although rare in Korea, SLO should be considered in the differential diagnosis of growth failure with intellectual disability, especially in patients with multiple congenital anomalies.

• 한국통신학회논문지
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• 제37A권11호
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• pp.961-971
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• 2012

This article is concerned with effective numerical techniques for partial differential equation (PDE)-based image restoration. Numerical realizations of most PDE-based denoising models show a common drawback: loss of fine structures. In order to overcome the drawback, the article introduces a new time-stepping procedure, called the method of nonflat time evolution (MONTE), in which the timestep size is determined based on local image characteristics such as the curvature or the diffusion magnitude. The MONTE provides PDE-based restoration models with an effective mechanism for the equalization of the net diffusion over a wide range of image frequency components. It can be easily applied to diverse evolutionary PDE-based restoration models and their spatial and temporal discretizations. It has been numerically verified that the MONTE results in a significant reduction in numerical dissipation and preserves fine structures such as edges and textures satisfactorily, while it removes the noise with an improved efficiency. Various numerical results are shown to confirm the claim.

• 한국통신학회논문지
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• 제35권3B호
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• pp.536-550
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• 2010

본 논문에서는 방송법과 통신법의 특성을 분석해 보고, 두 가지 법의 공통된 규제 특성과 차별적 규제특성을 도출해 냄으로써 방송통신 융합 환경에서 방송통신 통합법이 지향해야 할 핵심적 규제논거를 제시하고자 하였다. 또한 방송법과 통신법에서 고유하게 추구하고 있는 가치를 도출해 내고, 이러한 가치가 통합법에서도 지속적으로 반영되어야 할 필요성이 있는지를 살펴보고, 이러한 가치들이 통합법에서 어떻게 수용되어야 하는지에 대한 방향 성을 제시하였다. 연구결과, 방송법과 통신법의 공통된 특징은 두 산업 모두 전통적으로 강력한 진입규제가 적용되었고, 보편적서비스로서의 가치를 실현하도록 요구되어 왔다는 것이다. 한편, 방송법과 통신법에서 각각 추구하고 있는 고유의 가치는 다양성의 확보와 접근성의 확보로 요약될 수 있다. 방송통신 통합법에서는 방송과 통신의 전통적 규제논거를 유지하면서 융합 환경에 맞도록 다양성과 접근성의 의미를 수정 보완해 나아갈 필요가 있다.

• 공업화학
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• 제30권2호
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• pp.178-185
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• 2019

결정화/응집 공정을 이용하여 금속/금속산화물/분자화약/산화제로 구성된 구형 4성분계 복합체 3종을 제조하였다. 열중량 분석(TGA) 및 시차주사열량법(DSC)에 의한 열 특성 분석 결과 복합체를 이룬 분자화약의 분해 구간이 단축됨을 관찰하였고, ammonium perchlorate(AP) 분해 생성물인 HCl 및 $ClO_2$에 의한 자가 촉매 반응에 의한 것으로 해석된다. 활성화 에너지 분석 결과 분자화약 분해 종료 구간에서 급격하게 활성화 에너지가 감소함을 확인할 수 있었으며, 이는 분자화약 분해 생성물 중 공통으로 발생하는 $HNO_2$에 의한 것으로 판단된다. 본 연구에서 복합체 열분해 분석 결과로부터 Distributed Activation Energy Model (DAEM)에 의해 모사된 활성화 에너지가 model-fitting 분석법인 Kissinger-Akahira-Sunose와 Flynn-Wall-Ozawa model에 의한 모사치보다 정확도가 대단히 우수함을 알 수 있었다.