• Korean Management Science Review
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• v.23 no.3
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• pp.243-257
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• 2006

ITU-T's NgN(Next generation Network) architecture is expected to offer a new Internet platforms such as QoS(Quality of Service) guaranteed services as it overcame the limitations of the existing best-effort Internet architecture. However, policy development crucial for the NgN framework(e.g., interconnections and billing) is lagging far behind technology development. For example, arguments over network neutrality clearly indicate little understanding of the Internet industry structure where diverse providers including ISP and CP coexist. This study employs a network economics approach to predict how the competitive landscape involving various providers will evolve under the traffic-based billing system under the NgN environment. Applied is the non-cooperative game theory, in particular, Stackelberg's repeated game in order to build and analyze model for competition among those providers. We also studied possible impacts that CPs would have on the competitive landscape if they have an option to replace ISP: i.e., CDN(Content Delivery Network) provider. Lastly, based on the model analysis and experiments, presented are their implications to policy development and tile future prospect.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.299-305
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• 2008

In a series of research papers, the authors have studied some of the most important models of a contemporary universities, such as: the research university, the entrepreneurial university and the digital university and construct their Generalized Net (GN) models. This paper is based on the case-studies of Sofia University, the Technical University of Munich and the University of Edinburgh. The main focus is to put the analysis of the processes of the functioning of a university which effectively integrates Information and Communication Technologies (ICT) in all university activities. A concrete example based on the process of course administration at University of Edinburgh is considered. This university is in a process of developing an integrated information system covering most of the university activities. The opportunity of using GNs as a tool for modeling such processes is analyzed as well.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.664-665
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• 2016

This paper proposes an identification system based on QR (Quick Response) code for production and disposal information of Internet of Things (IoT) devices. Three thousands and five hundreds of electronic devices have replaced and discarded in South Korea in a year, and twenty millions to fifty millions tons of e-wastes have happened throughout the world every year. According to Gartner, market research institution, the number of IoT devices will increase from 2.3 billions in 2013 to 30 billions in 2020, however, the regulations and systems which take into account environment were not prepared. The identification systems for reflecting information of devices, which are produced or discarded, are required to resolve the problem. The proposed identification system based on QR code can store much more massive data such as the producer, product's model, serial number, recycling rate, recovering rate, recyclability rate, recoverability rate than RFID (Radio-Frequency Identification). Also, users can immediately recognize production and disposal information by a QR code application in a smartphone.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1605-1608
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• 2003

Today, E-Business develop because, Internet diffuse rapidly. Variety function and excellence performance needs for changeable user's requirement. So, EJB comes Component's addition and modify. For Component adds Function, Existing System modifies all of the source code. In EJB Component System, but, modifies simple source code. But, Today's System don't have cleary way that assembly component and design system. This Paper used design pattern for maintain of the component. this paper describes EJB Design Pattern using Abstract Factory Pattern. And EJB Component that used Pattern, decribes advantage and disavantage.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.13-14
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• 2008

This paper describes the optimal PSS parameter design for the PSS of EX2000 excitation system. The suggested tuning technique uses the model-based PSS tuning method which have three steps: generation system modeling, determination of PSS parameters, and on-site test. Using this method, the PSS parameters of EX2000 system in Dangjin T/P #4 was designed and verified by linear analysis program, PSS/E, and EMTDC/PSCAD.

• Journal of Digital Convergence
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• v.2 no.1
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• pp.57-73
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• 2004

Due to the rapid development of Information Technology and the Internet, e-business has bloomed and prevailed recently. As the result of this phenomenon, enterprises introduce CRM as a new process accessible to customers. The purpose of this study is to examine the factors affecting the performance of CRM based on precedent theoretical studies. So, the empirical test is conducted to various hypotheses related to the research model. 206 questionnaires for this study are collected. The result of how the organizational characteristics influence on the performance of CRM shows that they have a positively significant effect on it in order of expert security, top management's support and customer information-centric culture, and department collaboration. Evaluation and compensation system don't influence on the performance of CRM directly.

• Interaction and multiscale mechanics
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• v.1 no.4
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• pp.437-448
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• 2008

This paper examined the stability of high-dense dislocation substructures (HDDSs) associated with martensite laths in High Cr steels supposed to be used for FBR, based on a series of dislocation dynamics (DD) simulations. The DD simulations considered interactions of dislocations with impurity atoms and precipitates which substantially stabilize the structure. For simulating the dissociation processes, a point defect model is developed and implemented into a discrete DD code. Wall structure composed of high dense dislocations with and without small precipitates were artificially constructed in a simulation cell, and the stability/instability conditions of the walls were systematically investigated in the light of experimentally observed coarsening behavior of the precipitates, i.e., stress dependency of the coarsening rate and the effect of external stress. The effect of stress-dependent coarsening of the precipitates together with application of external stress on the subsequent behavior of initially stabilized dislocation structures was examined.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.370-378
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• 2008

The CEDA(Certified E-Document Authority) is a reliable third party that deposit electronic document having legal effects securely, and verify contents of document or transmission. This paper focuses on a function of secure transmission among several important functions, and implements public key encryption system for secure transmission when server and user communicate for image transmission. This paper follows a standard fundamental rule of X.509 in ITU-T, and it uses symmetric encryption algorithm to raise speed of a large data operation. A key of symmetric encryption algorithm is encrypted by private key in public key system, it protects to be modified using digital signature for data integrity. Also it uses certificates for mutual authentication.

• Journal of the Korean Vacuum Society
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• v.22 no.6
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• pp.327-334
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• 2013

Long-wave infrared detectors using the type-II InAs/GaSb strained superlattice (T2SL) material system with the nBn structure were designed and fabricated. The band gap energy of the T2SL material was calculated as a function of the thickness of the InAs and GaSb layers by the Kronig-Penney model. Growth of the barrier material ($Al_{0.2}Ga_{0.8}Sb$) incorporated Te doping to reduce the dark current. The full width at half maximum (FWHM) of the $1^{st}$ satellite superlattice peak from the X-ray diffraction was around 45 arcsec. The cutoff wavelength of the fabricated device was ${\sim}10.2{\mu}m$ (0.12 eV) at 80 K while under an applied bias of -1.4 V. The measured activation energy of the device was ~0.128 eV. The dark current density was shown to be $1.0{\times}10^{-2}A/cm^2$ at 80 K and with a bias -1.5 V. The responsivity was 0.58 A/W at $7.5{\mu}m$ at 80 K and with a bias of -1.5 V.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.36-45
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• 1996

The precise estimation of the reliability and life of the Ravigneaux planetary gear train used in an automatic transmission is necessary in order to enable accurate material and geometric properties to reliability distrobution and the number of load cycles at failure. These are critical for the proba- bilistic design of complex planetary gear system as Ravigneaux type particularly during various gear ratios. The Ravigneaux planetary gear train has five gears, such as a forward and a reverse sun gear, a short and a long pinion, and an annulus gear. In this paper, the Ravigneaux gear system is analyzed to figure out the reliablity distribution. i.e. the probability of survival in the system without its overhaul. First, the reliablity method based on the Weibull distribution is used in conjuction with the Palmgren's model to predict both the individual reliabilities of its components and the nimber of load cycles when the system failed. Then using the presented method, the life of the Ravigneaux gear system can be determined. Alwo the different design parameters such as tooth face width, material property, and Weibull exponent are applied and reached to optimal ones. Thus, the precise evaluation of the reliability and life of the Ravigneaux planetary gear train used in an automatic transmission can be effectively carried out.