• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.49-57
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• 2016

A modular multilevel converter is widely adapted for a high-voltage direct current power transmission system. This study proposes a design methodology for a novel digital control that mitigates the negative effects caused by time delay, including communication transport delay for a modular multilevel converter. The modeling and negative effect of time delay are analyzed theoretically in a frequency domain, and its compensation methodology based on an inverse model is described fully with practical considerations. The proposed methodology is verified through several simulation results using a modular 21-level converter system.

• Journal of Internet Computing and Services
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• v.14 no.4
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• pp.35-42
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• 2013

Nowadays many tasks are performed using the Web. Accordingly, many web-based application systems with various and complicated functions are being requested. In order to develop such web-based application systems efficiently, object-oriented analysis and design methodology is used, and Java EE(Java Platform, Enterprise Edition) technologies are used for its implementation. The security issues have become increasingly important. For such reasons, Java EE provides mechanism related to security but it does not provide interconnections with object-oriented analysis and design methodology for developing web application system. Consequently, since the security method by Java EE mechanism is implemented at the last step only, it is difficult to apply constant security during the whole process of system development from the requirement analysis to implementation. Therefore, this paper suggests an object-oriented analysis and design methodology emphasized in the security for secure web application systems from the requirement analysis to implementation. The object-oriented analysis and design methodology adopts UMLsec, the modeling language with an emphasis on security for the requirement analysis and system analysis & design with regard to security. And for its implementation, RBAC (Role Based Access Control) of servlet from Java EE technologies is used. Also, the object-oriented analysis and design methodology for the secure web application is applied to online banking system in order to prove its effectiveness.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.E2
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• pp.83-91
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• 2008

This work investigated the methodology to simultaneously optimize the ozone and relative humidity composition for the $NO_x$ degradation using soil biofilter. Experiments were made as a function of inlet ozone concentration ($0{\sim}1,770\;ppb$) and relative humidity ($38{\sim}81%$). Factorial design ($2^2+3$) and response surface methodology by central composite designs were used to examine the role of two factors and optimal response condition on $NO_x$ degradation. It was found that a second-order response surface model can properly interpret the experimental data with an $R^2$-value of 0.9730 and F-value of 71.83, based on which the maximum $NO_x$ degradation was predicted up to 92.8% within our experimental conditions.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.283-284
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• 2008

A cross-layer optimization is becoming a popular design methodology for the IP based next generation wireless network. We begin by investigating a cross-layer optimization scheme to enhance the system performance in wireless networks. By applying cross-layer optimization methodology to WiBro distributed network, the WiBro systems are expected to gain significant performance improvement and resource utilization enhanced. For further study we highlight some open challenges and new opportunities for cross-layer design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.275-282
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• 2006

System algorithms estimated by deterministic input may occur the error between predicted and actual output. Especially, actual system can't predict the exact outputs due to uncertainty and tolernce of input parameters. A single output to a set of inputs has a limited value without the variation. Hence, we should consider various scatters caused by the load assessment, material characteristics, stress analysis and manufacturing methods in order to perform the robust design or etimate the reliability of structure. The system design with uncertainty should perform the probabilistic structural optimization with the statistical response and the reliability. This method calculated the probability distributions of the characteristics such as stress by combining stress analysis, response surface methodology and Monte Carlo simulation and got the probabilistic sensitivity. The sensitivity of structural response with respect to in constant design variables was estimated by fracture probability. Therefore, this paper proposed the probabilistic reliability design method for fracture of uncorved freight end beam and the design criteria by fracture probability.

• Asia pacific journal of information systems
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• v.10 no.1
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• pp.81-106
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• 2000

Recently there have been many efforts to develop hypermedia systems. Hypermedia applications can be categorized into process-oriented or contents-oriented. However, it is not a trivial task to build contents-oriented hypermedia in a systematic fashion. The contents-oriented hypermedia systems are developed primarily for the applications of marketing or information services. This paper proposes a methodology for a contents-oriented hypermedia system. Hypermedia contents are typically structured in the form of hierarchies. An index node can be used in order to give an effective access to this hierarchical structure. The proposed methodology employs three types of nodes(contents, index and function) and various navigation mechanisms, and helps design contents-oriented hypermedia systematically. Furthermore, various design techniques are proposed for maintaining contents-oriented hypermedia systems that have an evolutionary feature. Two real-life cases are illustrated to demonstrate the applicability of the methodology.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.203-211
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• 2012

Network security infrastructure is constantly developing based on the combination and blending of various types of devices. From the form of distributed control, the phased defense policy such as fire walls, virtual private communication network, invasion prevention system, invasion detection system, corporate security management, and TSM (Telebiometrics System Mechanism), now it consolidates security devices and solutions to be developed to the step of concentration and artificial intelligence. Therefore, this article suggests network security infrastructure design types concentrating security devices and solutions as platform types and provides network security infrastructure design selecting methodology, the foundational data to standardize platform design according to each situation so as to propose methodology that can realize and build the design which is readily applied and realized in the field and also can minimize the problems by controlling the interferences from invasion.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1556-1562
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• 1999

The various kinds of object-oriented methodology were provided for the development of flexible software. However, they do not automatically make the reusable and robust Object-Oriented software systems. The Object-Oriented mechanism is simply used as the means to obtain the aim. We have heard many complaints from the developers that methods did not give concrete design guidance. Methodologists' effort and make reusable information in the design phase. The relation between the Object-Oriented methods and the design patterns is mutually complementary, and they play a role as a valuable design guidance in the development of the Object-Oriented system. This paper show the interaction between OMT which is most well-known in the Object-Oriented Methodology and Facade, Mediator and Observer designed by Gamma. We suggest the clear solution for concrete design knowledge and reusability of them by applying design patterns to Object-Oriented Methodology.

• Proceedings of the Korea Society of Design Studies Conference
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• 2002.05b
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• pp.174-175
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• 2002

• International Journal of Concrete Structures and Materials
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• v.4 no.1
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• pp.25-36
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• 2010

This paper presents the influence of various flexural strengthening design criteria specified by three important design guidelines (ACI440, TR55, FIB14) on the resulting strength, ductility and conservativeness of FRP strengthened RC elements. Various generalised mathematical relations in non-dimensional form are presented that can be employed to develop design aids for the FRP-strengthening process. A design methodology is prescribed based on these equations enabling the designer to optimally and intuitively incorporate sufficient ductility while designing for strength. In order to better interpret conservativeness within design codes, four distinct levels of embedded conservativeness are identified, which cover the entire range of sources of conservativeness. Finally, a detailed parametric study is presented, using the proposed design equations and methodology, to determine the influence of each of these four levels of conservativeness on final design solutions. Specific criteria that are useful while calibrating design guidelines are also presented.