• KSBB Journal
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• v.23 no.6
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• pp.474-478
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• 2008

UDP-glucose regeneration system using metabolic engineeringis unique and efficient strategy for oligosaccharide synthesis. To exploit the efficient UDP-glucose regeneration system, we introduced four enzymes, which would be important in partitioning the flux of UDP regenerationsuch as UDP-glucose pyrophosphorylase, UDP-Kinase gene, UDP-galactose 4-epimerase, and $\beta$-1, 4-galactasyltrasnsferase, into E. coli AD202. To determine the optimal expression level for UDP-regeneration, LacNAc concentration was compared depending on IPTG concentration. 0.5 mM IPTG induction showed the higher oligosaccharides synthesis. Using metabolic engineering under optimal IPTG induction, LacNAc synthesis of AD202/pQNGLU increased until 16 h and showed the 1.34 mM. This concentration is 10 times higher than that of control strain at same reaction time. Lactose of AD202/pQNGLU showed the maximum synthesis of 0.39 mM at 16 h and showed the 2.6 times higher than that of control strain.

• KSBB Journal
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• v.21 no.4
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• pp.298-301
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• 2006

A gene(GeneBank AF 135796) coding for a trehalose synthase from Thermus caldophilus GK24 was cloned into Escherichia coli K12 using five vector systems. The constitutive expression system(pHCETS) which shows the highest trehalose synthase activity from flask culture of recombinant E. coli was selected for the production of trehalose from maltose. For the shake flask culture, the final dry cell weight was 0.9 g/L and the trehalose synthase activity was 25 U/mL. Fed-batch culture of recombinant E. coli harboring plasmid pHCETS which uses the glycerolas a carbon source was performed in jar fermentor: the dry cell weight of 20 g/L and the trehalose synthase activity of 13.7 U/mL were attained in 48 h.

• Korean Journal of Computational Design and Engineering
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• v.17 no.3
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• pp.216-223
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• 2012

Bill of material (BOM), which structurally represents the relation among parts constructing a product, is usually created when enterprises start to develop a new product. And it is shown as various types of BOM according to business needs and usage such as eBOM (engineering BOM), gBOM (green BOM), mBOM (manufacturing BOM), pBOM (process BOM), etc. eBOM, generally called BOM and created in the design stage of the new product, includes the drawing information of parts in the view of product function. eBOM is extended to gBOM adding the material information of parts to cope with international regulations for environment. eBOM is transformed to mBOM, which includes manufacturing sequence of parts and adds some parts required to fabricate parts and to assemble the product. mBOM is also extended to pBOM adding the process information of each part and additional assembly processes. This study introduces the concept of multi-BOM covering eBOM, gBOM, mBOM and pBOM, and proposes an advanced way to manage product data using multi-BOM system. The multi-BOM system proposed is to manage their relations using transformation function of BOM and master information of all BOMs.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.194-194
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• 2018

• 시스템엔지니어링워크숍
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• s.4
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• pp.65-69
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• 2004

Abstract Tilting train has been developed to increase the oprational speed of the trains on conventional lines which have many curves. This train are tilted at curves to compensate for unbalanced carbody centrifugal acceleration to a greater extent than compensation produced by the track cant, so that passengers do not feel centrifugal acceleration and thus trains can run at higher speed at curves. This paper developed PDM(product data management) to make a system engineering of TTX(Tilting Train eXpress) with maximum operation speed 180 km/h.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.649-657
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• 1992

Transmission error for a stepping motor-timing belt drive system is investigated experimentally and analytically. From FFT analysis of the experimental results, it is found that the transmission error consists of three periodic errors : (1) error by the stepping motor per one resolution angle theta.$_{m}$, (2) error by the pulley eccentricity per one revolution theta.$_{e}$, and (3) error by the meshing effect between the belt and the pulley teeth per one pitch revoltion theta.$_{p}$. In order to investigate the effects of some design parameters on the transmission error, the dynamic models of the stepping motor-timing belt drive system are derived by Bondgraph. According to the simulation results, as the belt total tension increases, theta.$_{m}$ and theta.$_{e}$ decrease due to the nonlinearity of the belt. In adition, the numerical and experimental results show that theta.$_{m}$ and theta.$_{e}$ of the loaded case are larger than those of the unloaded case. The analytical results are in good accordance with the experimental results.sults.s.sults.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.213-218
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• 2015

In parallel with evolving information communication technology, M2M(Machine-to-Machine) industry has implemented multi-functional and high-performance systems, and made great strides with IoT(Internet of Things) and IoE(Internet of Everything). Authentication, confidentiality, anonymity, non-repudiation, data reliability, connectionless and traceability are prerequisites for communication security. Yet, the wireless transmission section in M2M communication is exposed to intruders' attacks. Any security issues attributable to M2M wireless communication protocols may lead to serious concerns including system faults, information leakage and privacy challenges. Therefore, mutual authentication and security are key components of protocol design. Recently, secure communication protocols have been regarded as highly important and explored as such. The present paper draws on hash function, random numbers, secret keys and session keys to design a secure communication protocol. Also, this paper tests the proposed protocol with a formal verification tool, Casper/FDR, to demonstrate its security against a range of intruders' attacks. In brief, the proposed protocol meets the security requirements, addressing the challenges without any problems.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.779-789
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• 2013

This study aimed to investigate the emulsifying properties of bovine lactoferrin in food emulsion system. First, lactoferrin solution was prepared to study its surface activities, such as surface adsorption characteristics and ${\zeta}$-potential. Second, some physicochemical properties of lactoferrin emulsion which resulted from variations of environmental conditions (i.e., pH or NaCl addition) were determined. As for surface adsorption characteristics evaluated by surface tension, it was decreased with increasing lactoferrin concentration in solution ($1{\times}10^{-5}{\rightarrow}0.2wt%$) and showed a plateau (${\fallingdotseq}44$mN/m) above 0.01 wt%. It was also changed with pH and the minimum value of 53.8 mM/m was observed at pI of lactoferrin. This was related to changes in ${\zeta}$-potential of the lactoferrin solution with respect to pH. Fat globule size of lactoferrin emulsion was decreased with increasing lactoferrin concentration and a stable emulsion was formed above 0.5 wt% lactoferrin in emulsion with fat globule size $d_{32}$ of ca. 0.33 ${\mu}m$ as confirmed by creaming stability experiment (i.e., Turbiscan). As with surface tension, fat globule size of lactoferrin emulsion also changed with pH and showed a maximum value at pI. As evaluated by Turbiscan, in the presence of NaCl, the lactoferrin emulsion showed instability in particular above 10 mM.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.280-286
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• 2012

Clean energy farming is the agricultural activity to improve an efficiency of agricultural energy use and to replace fossil fuels. This study was carried out to establish the clean energy farming system in the controlled cultivation of vegetable crop (cucumber) adopting the biogas production facility. In order to design the clean energy farming system, mass and energy balance was analyzed between the controlled cultivation system and the biogas production facility. Net yearly heating energy demands ($E_{YHED}$) of forcing and semi-forcing cultivation types were 48,697 and $13.536Mcal\;10^{-1}$ in the controlled cultivation of vegetable cucumber. To cover these $E_{YHED}$, the pig slurry of 511 and $142m^3\;10a^{-1}$ (biogas volume of 9,482 and $2,636Nm^3\;10a^{-1}$, respectively, as 60% methane content) were needed in forcing and semi-forcing cultivation types. The pig slurry of $511m^3\;10a^{-1}$ caused N 1,788, $P_2O_5$ $511kg\;10a^{-1}$ in the forcing cultivation type, and the pig slurry of $142m^3\;10a^{-1}$ caused N 497, $P_2O_5$ $142kg\;10a^{-1}$ in the semi-forcing cultivation type. The daily heating energy demand ($E_{i,DHED}$) by the time scale analysis showed the minimum $E_{i,DHED}$ of $7.7Mcal\;10a^{-1}\;day^{-1}$, the maximum $E_{i,DHED}$ of $515.1Mcal\;10a^{-1}\;day^{-1}$, and the mean $E_{i,DHED}$ of 310.2 in the forcing cultivation type. And the minimum $E_{i,DHED}$, the maximum $E_{i,DHED}$, and the mean $E_{i,DHED}$ were 5.3, 258.0, and $165.1Mcal\;10a^{-1}\;day^{-1}$ in the semi-forcing cultivation type, respectively. Input scale of biogas production facility designed from the mean $E_{i,DHED}$ were 3.3 and $1.7m^3\;day^{-1}$ in the forcing and the semi-forcing cultivation type. The maximum $E_{i,DHED}$ gave the input scale of 5.4 and $2.7m^3\;day^{-1}$ in the forcing and the semi-forcing cultivation type.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6C
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• pp.763-769
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• 2004

It is known that a bent function corresponds to a perfect nonlinear function, which makes it difficult to do the differential cryptanalysis in DES and in many other block ciphers. In this paper, for an odd prime p, quadratic p-ary bent functions defined on finite fields are given from the families of p-ary sequences with optimal correlation properly. And quadratic p-ary bent functions, that is, perfect nonlinear functions from the finite field F $_{p^{m}}$ to its prime field $F_{p}$ are constructed by using the trace functions. trace functions.