7,095 research outputs found
Effects of organizational characteristics on EDI implementation in Korea
No full textElectronic data interchange (EDI) has been increasingly adopted in Korean industries to facilitate their online transactions with customers and suppliers. We investigate organizational factors affecting successful implementation of EDI in current Korean industries. Regression models are developed and tested using survey results from 110 Korean companies that have been using EDI
The impact of measurement scale and correlation structure on classification performance of inductive learning and statistical methods
No full textThis is a comparative study of inductive learning and statistical methods using the simulation approach to provide a generalizable results. The purpose of this study is to investigate the impact of measurement scale of explanatory variables on the relative performance of the statistical method (probit) and the inductive learning method (ID3) and to examine the impact of correlation structure on the classification behavior of the probit method and the ID3 method. The simulation results show that the relative classification accuracy of ID3 to probit increases as the proportion of binary variables increases in the classification model, and that the relative accuracy of lD3 to probit is higher when the covariance matrices are unequal among populations than when the covariance matrices are equal among populations. The empirical tests on ID3 reveal that the classification accuracy of lD3 is lower when the covariance matrices are unequal among populations than when the covariance matrices are equal among populations and that the classification accuracy of lD3 decreases as the correlations among explanatory variables increases
Field emission characteristics of COSi2/TaN-coated silicon emitter tips
No full textThis work has improved the emission characteristics of Si emitter tips by coating a CoSi2/TaN bilayer on the tips. The CoSi2 layer was grown in situ by a reactive chemical-vapor deposition of cyclopentadienyl dicarbonyl cobalt at 650 degreesC. The TaN was then deposited on the CoSi2 layer at 550 degreesC by a reactive sputtering of Ta with N as a reactive gas. The CoSi2/TaN-coated emitters showed a lower turn-on voltage and higher emission current than the CoSi2- or TaN-coated emitters due to the low work function by TaN and the easy transport of electron by CoSi2 with low resistivity. The long-term emission stability of CoSi2/TaN-coated Si emitter was as good as TaN-coated emitter
A study on ray tracing method for CFD simulations of laser keyhole welding: Progressive Search Method
No full textAPWM adapted half-bridge LLC converter with voltage doubler rectifier for improving light load efficiency
No full textLLC converter is widely used in various applications due to its simple structure and zero voltage switching capability. To achieve high efficiency, LLC converter is usually designed to operate near the resonant frequency over the entire load conditions. However, a constant core loss of the main transformer due to the constant frequency operation has a bad effect on the efficiency in a light load condition where the core loss dominates the total loss. Therefore, it is essential to reduce transformer core loss in order to improve light load efficiency. Adapting asymmetric pulse-width modulation (APWM) in a half-bridge LLC resonant converter with voltage doubler rectifier for improving light load efficiency has been proposed. By adapting APWM, the core loss can be reduced dramatically in the light load condition, because both the switching frequency and the flux swing of the transformer are reduced. Furthermore, the proposed method does not affect the design of the converter. The experimental results with 400-250 V input and 100 V/2 A output prototype converter support the effectiveness of the proposed method.
Chosen logistics processes in Škoda JS
No full textThis master thesis deals with the purchase and sale process in Škoda JS company. The aim of this work is to assess whether the setting of the purchase and sale process is met by the company also within a real business case, in compliance with set controls, and whether the degree of perfect delivery is sufficient. In the introduction, the author specifies the basic terms: logistics, logistic chain, customer benefits, information systems in logistics, buying and selling. The following chapter introduces Škoda JS company, including the sphere of its entrepreneurial activity. This chapter also deals with the nuclear power industry. In the crucial chapter, the author describes the process of purchase and sale in Škoda JS company and compares it with a real business case. In conclusion, the author evaluates discrepancies and suggests recommendations to avoid them
EXPERIMENTAL-VERIFICATION OF SUPERPLASTIC SHEET-METAL FORMING ANALYSIS BY THE FINITE-ELEMENT METHOD
No full textThe numerical result for superplastic sheet-forming simulation is compared with the experimental result to verify the validity of the finite-element code developed. The code calculates the optimum pressure cycle, the deformed shapes, and the distributions of the strain and strain-rate in the blow-forming processes. The calculation deals with the maximization of the strain-rate sensitivity, the protection of the localized deformation, the consistency of the desired strain-rate, and the control of the hour-glass mode and locking phenomenon. The comparison demonstrates the validity of the present algorithm and its results, especially in respect of the optimum pressure cycle, where there is only a slight difference between the two results
Comparison of the extracellular proteomes of Escherichia coli B and K-12 strains during high cell density cultivation
No full textEscherichia coli BL21 (DE3) and W3110 strains, belonging to the family B and K-12, respectively, have been most widely employed for recombinant protein production. During the excretory production of recombinant proteins by high cell density cultivation (HCDC) of these strains, other native E. coli proteins were also released. Thus, we analyzed the extracellular proteomes of E. coli BL21 (DE3) and W3110 during HCDC. E. coli BL21 (DE3) released more than twice the amount of protein compared with W3110 during HCDC. A total of 204 protein spots including 83 nonredundant proteins were unambiguously identified by 2-DE and MS. Of these, 32 proteins were conserved in the two strains, while 20 and 33 strain-specific proteins were identified for E. coli BL21 (DE3) and W3110, respectively. More than 70% of identified proteins were found to be of periplasmic origin. The outer membrane proteins, OmpA and OmpF, were most abundant. Two strains showed much different patterns in their released proteins. Also, cell density-dependent variations in the released proteins were observed in both strains. These findings summarized as reference proteome maps will be useful for studying protein release in further detail, and provide new strategies for enhanced excretory production of recombinant proteins.This work was supported by the Korean Systems Biology Research
Grant (M10309020000-03B5002-00000) of the Ministry
of Science and Technology. Further supports by LG Chem Chair
Professorship, IBM SUR Program, Microsoft, and by the KOSEF
through the Center for Ultramicrochemical Process Systems are
appreciated
Proteome-level responses of Escherichia coli to long-chain fatty acids and use of fatty acid inducible promoter in protein production
No full textIn Escherichia coli, a long-chain acyl-CoA is a regulatory signal that modulates gene expression through its binding to a transcription factor FadR. In this study, comparative proteomic analysis of E. coli in the presence of glucose and oleic acid was performed to understand cell physiology in response to oleic acid. Among total of 52 proteins showing altered expression levels with oleic acid presence, 9 proteins including AldA, Cdd, FadA, FadB, FadL, MalE, RbsB, Udp, and YccU were newly synthesized. Among the genes that were induced by oleic acid, the promoter of the aldA gene was used for the production of a green fluorescent protein (GFP). Analysis of fluorescence intensities and confocal microscopic images revealed that soluble GFP was highly expressed under the control of the aldA promoter. These results suggest that proteomics is playing an important role not only in biological research but also in various biotechnological applications. Copyright (c) 2008.We thank Z. W. Lee (Korea Basic Science Institute, Daejeon,
Republic of Korea) for his help with the confocal microscopy.
This work was supported by the Korean Systems Biology Research
Grant (M10309020000-03B5002-00000) of the Ministry
of Science and Technology. Further supports by LG
Chem Chair Professorship, IBM SUR program, Microsoft,
and by the KOSEF through the Center for Ultramicrochemical
Process Systems are appreciated
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