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Seoul, South Korea

Kim Y.J.,Sogang University | Lee J.M.,Dongyang Mirae University | Koo C.,Kyung Hee University | Nam K.,Management Information Systems
International Journal of Information Management | Year: 2013

Recent studies on IT outsourcing have examined the effect of contract specification and relationship strength on IT outsourcing performance in a separate manner. Previous studies, however, ignored the importance of the governance effectiveness that bonds contractual control and relationship strength together to deliver expected outcomes in IT outsourcing exchange. In this paper, we propose a model of IT outsourcing management where governance effectiveness mediates the effect of both contractual control and relationship strength on IT outsourcing performance. We collected data from 143 client companies of IT outsourcing and analyzed it using the PLS method. Our findings show that both contract specification and relationship strength significantly influence governance effectiveness, although contract specification carries the more effect on governance effectiveness than relationship strength does. The governance effectiveness in turn mediates the effect of contract specification and relationship strength on three sub-dimensions of outsourcing performance: cost efficiency, performance improvement, and overall satisfaction. The results and implications are further discussed. © 2013 Elsevier Ltd. All rights reserved.

Shin S.-S.,Dongyang Mirae University
Transactions of the Korean Institute of Electrical Engineers | Year: 2015

A Chebyshev filter is well known for having a sharp skirt characteristic and equi-ripple. On the other hand, a Butterworth filter has a smooth skirt characteristic and maximally flat ripple. This paper analyzes the skirt characteristics of the filters with the cascade connection. The paper deals with the Chebyshev BPF, Cascading Chebyshev BPF, Butterworth BPF, Cascading Butterworth∗ Chebyshev BPF. First of all, the paper designs the prototype analog LPF in order to analyze skirt characteristics of the BPFs. Then the paper does the frequency transformation into the BPFs and tests the BPFs with cascading them. As a result, the skirt characteristics of the Chebyshev BPF was the sharpest and those of the Cascading Chebyshev BPF, Butterworth BPF," Cascading Butterworth∗ Chebyshev BPF was superior in order. The validity of the paper was confirmed through minute measurements of test results. Copyright © The Korean Institute of Electrical Engineers.

Yim K.B.,Dongyang Mirae University | Yim J.,NASA
International Journal of Precision Engineering and Manufacturing | Year: 2012

The dynamic behavior of a flexible shaft with a disk subjected to axial forces has been studied by employing the transfer matrix approach. The conventional transfer matrix was modified to include the applied axial force, and then integrated into a computer program to investigate the effect of the load force on the stability and the natural frequencies of overhung rotor systems. Two overhung rotor systems are considered. One is the cantilevered rotor and the other is the overhung rotor with an intermediate support. The gyroscopic effect of the rotor strongly influences the dynamic behavior of the shaft-disk system under axial forces not only by increasing the critical force for the stability but also by changing the instability type from divergence to flutter. © KSPE and Springer 2012.

Cho S.,Dongyang Mirae University | Lee J.Y.,Samsung
Electronic Materials Letters | Year: 2010

Thermal management issues with IC packages have been growing as electronic systems have become smaller with a higher functionality. Since the high junction temperature of IC packages induces the low performance and malfunction of electronic systems, the thermal dissipation capability of electronics is important for stable electrical performance and electro-mechanical reliability. However, the conventional cooling methods that depend on air flow path and heat sink structure is not sufficient to meet the growing thermal requirements of IC packages. Since there is limit on conventional design, such as optimization air flow path and heat sink structure, to dissipate more heat through an exhaust fan system. The main purpose of the present research is to reduce the junction temperature of the IC package by using a Printed Circuit Board (PCB) coated with new Photo-imageable Solder Resist (PSR) that has high thermal conductivity. The thermal conductivity of the newly developed PSR is about five times as high as that of the conventional PSR for PCB(0.23~0.25W/m·K). The PCB was prepared by the EIA/JEDEC standard, JESD51-7. Experimental and finite element analyses were performed to investigate the effect of SR on thermal dissipation capability. The experimental and FE results show that the high thermal conductivity of PSR can reduce the steady-status regulator surface temperature by about 3~8K as an air flow conditions around PCB. Also, the high thermal conductivity of SR is more effective under a low air heat transfer coefficient condition. Therefore, it is believed that an improved heat transfer with a PSR of high thermal conductivity should provide stable electrical performance for the IC package.

Chee G.-J.,Dongyang Mirae University | Chee G.-J.,Japan Agency for Marine - Earth Science and Technology
Talanta | Year: 2011

Trichloroethylene (TCE) is a toxic, recalcitrant groundwater pollutant. TCE-degrading microorganisms were isolated from various environments. The aerobic bacteria isolated from toluene- and tryptophan-containing media were Pseudomonas sp. strain ASA86 and Burkholderia sp. strain TAM17, respectively; these are necessary for inducing TCE biodegradation in a selective medium. The half-degradation time of TCE to a concentration of 1 mg/L was 18 h for strain ASA86 and 7 days for strain TAM17. While identifying toluene/TCE degradation genes, we found that in strain ASA86, the gene was the same as the todC1 gene product encoding toluene dioxygenase identified in Pseudomonas putida F1, and that in strain TAM17, the gene was similar to the tecA1 gene product encoding chlorobenzene dioxygenase identified in Burkholderia sp. PS12. A novel TCE biosensor was developed using strain ASA86 as the inducer of toluene under aerobic conditions. The TCE biosensor exhibited a linear relationship below 3 ppm TCE. Detection limit of the biosensor was 0.05 ppm TCE. The response time of the biosensor was less than 10 min. The biosensor response displayed a constant level during a 2 day period. The TCE biosensor displayed sufficient sensitivity for monitoring TCE in environmental systems. © 2011 Elsevier B.V. All rights reserved.

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