• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.579-582
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• 2004

This paper presents controller design of a static var compensator using PWM Cuk AC-AC converter. The PWM Cuk AC-AC converter is modelled by using complex circuit DQ transformation and perturbed around the operating point whereby the small signal system characteristics is analytically obtained. Finally, the PSIM simulations show the validity of the modelling and analysis.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.36-41
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• 1988

Analog and Digital Speed Control Systems have mutually complementary properties. Analog System has good dynamic characteristics and moderate steady-state accuracy and can be implemented economically with operational a ampliers. Digital System, on the contray, has good static accuracy, but relatively poor dynamic property. So, a hybrid system which uses both digital and analog control can have good static and dynamic characteristics. In this paper, it is shown that a simple digital controller can improve steady-state accuracy of existing analog control system satisfactorily, and some design criteria are presented also.

• Journal of applied mathematics & informatics
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• v.18 no.1_2
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• pp.1-23
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• 2005

The decentralized static output feedback design problem is considered. A constrained trust region method is developed that solves this optimal control problem when a complete set of state variables is not available. The considered problem is interpreted as a non-linear (non-convex) constrained matrix optimization problem. Then, a decentralized constrained trust region method is developed for this problem class exploiting the diagonal structure of the problem and using inexact computations. Finally, numerical results are given for the proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1624-1627
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• 2008

This paper deals with a linear matrix inequality (LMI) approach to the design of a PID controller for an attraction type magnetic levitation system. First, we convert the $H_ {\infty}$ PID controller problem into a static output feedback problem. We then solve the static output problem by using the recently developed penalty function method. Numerical experiments show the effectiveness of the proposed algorithm.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.373-376
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• 2006

There are representative two performance evaluation methods for performance-based design(PBD) of reinforced concrete structures by the nonlinear static analysis, one method includes the capacity spectrum method(CSM) suggested in ATC-40(996) and the other is the displacement coefficient method(DCM) in FEMA-273(1997). The objective of this paper is to compare and verify two methods and suggest the displacement-based design for new performance evaluation of reinforced concrete structures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.799-800
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• 2011

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.110-119
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• 2018

Blockchain technology has been highly evaluated for its contracts (contracts for sale, real estate contracts) because of its excellent security, including integrity and non-repudiation. In a blockchain, these contract services can be developed using a technology called a smart contract, and several blockchain platforms provide a programming language for developing smart contracts. Bitcoin and Ethereum, typical blockchain platforms, provide the Bitcoin Scripts and Solidity languages. Using these programming languages, we can develop the smart contract, a digital contract that can be processed dynamically. Smart contracts are being developed in a variety of areas, but studies of designs based on a blockchain are insufficient. In this paper, we propose a meta-model and a static/dynamic design method based on Unified Modeling Language (UML) for smart contracts based on Ethereum. We propose a method for static design attributes and functions of smart contracts, and propose a technique for designing structures among contracts. Dynamic design proposes a technique for designing deployment, function calls, and synchronization among smart contracts, accounts, and blocks within a blockchain. Experiments verify the validity of the design method by applying the static/dynamic design method through real estate contracts.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.391-393
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• 2004

For performance and stability of a synchronized system, we need an efficient Clock Tree Synthesis(CTS) methodology to design clock distribution networks. In a system-on-a-chip(SOC) design environment, CTS effectively distributes clock signals from clock sources to synchronized points on layout design. In this paper, we suggest the pre-layout analysis of the clock network including gated clock, multiple clock, and test mode CTS optimization. This analysis can help to avoid design failure with potential CTS problems from logic designers and supply layout constraints so as to get an optimal clock distribution network. Our new design flow including pre-layout CTS analysis and structural violation checking also contributes to reduce design time significantly.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.04a
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• pp.253-259
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• 1997

A software for design of turbine bearings has been developed based on both the theoretical analysis and experimental investigation. Static and dynamic performance, i.e. load capacity, frictional loss, temperature distribution, stiffness and damping coefficients, stability etc., can be obtained by using this software taking into account the effects of three dimensional variation of lubricant viscosity, turbulence and inlet pressure. A performance test rig was developed by self-design and technology, which was used to verify static and dynamic characteristics and to investigate the proper boundary conditions for theoretical analysis. Consequently HANJUNG has developed the self-design technology for design of turbine bearings for power plants.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.69-77
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• 1999

The stabbing guide is often used to guide an add-on pile into an existing pile in offshore jacket installation. It provides a pile alignment for a welding tie-in in static condition as well. Even stabbing guide is an essential component in pile installation, it is not considered as a permanent offshore structure. In this regard, there is not a define design guideline proposed. In API RP 2A WSD, it briefly define the design considerations of stabbing guide. The failure of stabbing guide can cause a greate economical loss and a serious impact to the project schedule. Stabbing guide design should consider many factors considering actual work conditions for both static and dynamic situations. In the paper, a design method is proposed by appling the plate theory and it is confirmed numerically with FEM modeling. The geometry of stabbing guide is assumed as a cylinder shape with various wall thickness and effective length. The various thickness, effective length and pile size are compared for stable stabbing guide design.