• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.9-12
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• 2008

PSC-I girder is widely used in designing bridge. Currently partial advanced country have constructed bridge with high strength concrete, while in-country rather less concrete strength(40MPa) has been used to build bridge girder. So, this paper presents characteristics and behavior of member casted by high strength concrete to apply practically. For this aim, 4 girders were fabricated to investigate performance and structural behavior. Prior to test, structural analysis was performed with common program. Steel gages and concrete gage were filled up to measure longitudinal and vertical strain of reinforcement and concrete. Linear Variable Differential Transducer and concrete surface gage were also set to measure deflection and strain of concrete. Load-deflection relation and crack mode were analyzed at transfer and test and compared with the structural analysis

• Asia-Pacific Journal of Business
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• v.11 no.2
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.4
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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.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.205-208
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• 1986

The 23 serovars of Bacillus thuringiensis strain were commonly gram-positive and motile, formed endotoxin crystals, produced acid and alkali in the KIA media, and acid from glucose, hydrolyzed starch, and reduced nitrate but did not produce H$_2$S, oxidase and indole, did not decompose lysine, ornithine, phenylalanine, malonate, lactose, dulcitol, adonitol, inositol, sorbitol, arabinose, raffinose, rhamnose, maltose, and xylose. Eighteen serovars were positive in the MR tests and 15 in the VP tests. Four serovars used citrate. Five serovars produced urease, 5 $CO_2$ from glucose, 2 DNase, and 15 lecithinase. Twelve serovars decomposed arginine, 11 did sucrose, 2 manitol, and 9 salicin Serovar tohokuensis did not hemolyze, but the others did.

• Journal of Power Electronics
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• v.10 no.4
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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.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.14 no.1
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.11
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.536-550
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• 2010

This study analyzes the characteristics of broadcasting law and telecommunication law and suggested the key legitimate of regulation where convergence law would go for in the convergence circumstances by drawing the common and differential characteristics of two laws. Moreover, in the value of inherent pursuit of broadcasting law and telecommunication law, this paper examined whether these values continued to be reflected in the convergence law, and indicated the direction how these values should adopt in the convergence law. The result of this study shows that strong entry regulation has applied to both broadcasting and telecommunications industry. Also, both industries have been required to be universal service to realize the value. Meanwhile, the pursuit of original value of broadcasting law and telecommunication law can be summarized as secure of access and diversity, respectively. In the convergence law, it is necessary to compensate and modify the meaning of access and diversity based on traditional regulation.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.178-185
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• 2019

Three spherical quaternary composites composed of metal/metal oxide/high explosive/oxidizer were prepared by a crystallization/agglomeration process. From the characteristics of composites by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), the shortening of the decomposition zone of high explosives in the quaternary composite was observed, which may be attributed to the autocatalytic reaction caused by $ClO_2$ or HCl which are ammonium perchlorate (AP) degradation products. The activation energy analysis showed that the activation energy abruptly decreases at the end of the decomposition zone of high explosives, and it was considered to be caused by $HNO_2$ which is common in decomposition products of high explosives. The activation energy predicted from complex pyrolysis results by the distributed activation energy model (DAEM) showed much better in accuracy than those by model-fitting methods such as Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa models.