• Convergence Security Journal
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• v.6 no.2
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• pp.61-69
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• 2006

For the efficient business, the telecommunication providers should have an attention for the minimization of the basic setup cost to implement the network infrastructure. Furthermore, the provision of the quality of service (QoS) to the service users is crucial for the service providers and vendors. In this paper, we propose the new algorithm to provide the user's QoS under the various traffic in the broadband convergence network. Using the NS-2 network simulator, we evaluate the QoS for the proposed algorithm, and compare those with the results of the previous differentiated service network.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.6
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• pp.266-271
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• 2000

The electric power industries are moving from the conventional monopolistic or vertically integrated environments to deregulated and competitive environments, where each participant is concerned with profit maximization rather than system-wide costs minimization. Consequently, the conventional least-cost approaches for the generation resource schedule can not exactly handle real-world situations. This paper presents a game theory application for analyzing power transactions and market design in a deregulated energy marketplace, where the market participants determine the net profits through the optimal bidding strategies. The demand elasticity of the energy price is considered for the realistic modeling of the deregulated marketplace.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.372-374
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• 2002

The Optimal Power Flow(OPF) is the optimization model that has different constraints and the specified objective function, which is very useful tool for efficient system and market operation in the competitive electricity market. The existed OPF models focus on the minimization of generation fuel cost under informed demand values at each bus Recently, the studies of OPF model with demand function considering the response behavior of customers in the deregulated electricity market have been executed. This paper implements the OPF model using demand function with specified price elasticity, and provides the analysis of related results.

• Transactions on Electrical and Electronic Materials
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• v.3 no.4
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• pp.1-4
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• 2002

As the application of semiconductor chips into electronics increases, it requires more complete integration, which results in higher performance. And it needs minimization in device design for cost saving of manufacture. Therefore oxide gap fill has become one of the major issues in sub-micron devices. Currently HDP (High-Density Plasma) CVD system is widely used in IMD (Inter Metal Dielectric) to fill narrower space between metal lines. However, HDP-CVD system has some potential problems such as plasma charging damage, metal damage and etc. Therefore, we will introduce about one of via resistance failure by metal damage and a preventive method in this paper.

• ETRI Journal
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• v.35 no.2
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• pp.200-206
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• 2013

Most of the literature on compressed sensing has not paid enough attention to scenarios in which the number of acquired measurements is insufficient to satisfy minimal exact reconstruction requirements. In practice, encountering such scenarios is highly likely, either intentionally or unintentionally, that is, due to high sensing cost or to the lack of knowledge of signal properties. We analyze signal reconstruction performance in this setting. The main result is an expression of the reconstruction error as a function of the number of acquired measurements.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.5
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• pp.83-89
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• 2010

In this paper, the dynamic response of a CNC 5 Axles machining center was analyzed and then controlled passively by using the dynamic absorber. For the simplification of the theoretical approach, the CNC 5 Axles machining center was modeled as a flexible beam(Bed) having a point mass(Column), two discrete systems(a Table-set and a dynamic absorber). Specifically by using the dynamic absorber, the dynamic response of a Table-set which be caused by the vibration of a flexible beam, was reduced down to the infinitesimal level. The optimal design factors of the dynamic absorber were obtained from the minimization of the cost function. It was found that the natural frequencies of a UT-380 machining center be varied due to the movement of the Table-set. In view of the dynamic response of a Table-set, the larger spring stiffness and mass of the dynamic absorber were found to give the greater reduction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.1 no.1
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• pp.113-124
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• 1997

Based on the recent developments of the reliability-based structural analysis and design as well as the extending knowledge on the probabilistic characteristics of load and resistances, the probability based design criteria have been successfully developed for many standards. Since the probabilistic characteristics depend highly on the local load and resistances, it is recognized to develop the design criterion compatible with domestic requirements. The existing optimum design methods, which are generally based on the structural theory and certain engineering exprience, do not realistically consider the uncertainties of load and resistances and the basic reliability concepts. This study is directed to propose a optimum design based Expected Total Cost Minimization on two-way slab system which could possibly replace optimum design based traditional provisions of the current code, based on the AFOSM reliablity theory.

• International Journal of Railway
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• v.3 no.3
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• pp.95-105
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• 2010

In this paper, a procedure is proposed to optimize bogie suspension parameters in view of minimizing wheel wear produced by curve negotiation, though meeting stability requirements. The problem is dealt with in the form of a constrained minimization problem, in which wheel wear evaluated over a given service scenario is introduced as the cost function to be minimized, and the requirements on vehicle stability are formulated in terms of constraints. The procedure is applied to the case of a non-powered passenger car for high-speed service, and the results obtained are discussed. It is shown that long wheelbase bogie may provide better overall performances than bogies having comparatively short wheelbase. Furthermore, a sensitivity analysis is performed, to define the effect on the optimization results of improving the performances of the yaw dampers in the bogie and of using a different wheel profile.

• Nuclear Engineering and Technology
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• v.23 no.1
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• pp.20-29
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• 1991

The system analysis for Korean nuclear power reactor option is made on the basis of reliability, cost minimization, finite uranium resource availability and nuclear engineering manpower supply constraints. The reference reactor scenarios are developed considering the future electricity demand, nuclear share, current nuclear power plant standardization program and manufacturing capacity. The levelized power generation cost, uranium requirement and nuclear engineering professionals demand are estimated for each reference reactor scenarios and nuclear fuel cycle options from the year 1990 up to the year 2030. Based on the outcomes of the analysis, uranium resource utilization, reliability and nuclear engineering manpower requirements are sensitive to the nuclear reactor strategy and associated fuel cycle whereas the system cost is not. APWR, CANDU longrightarrow FBR strategy is to be the best option for Korea. However, APWR, CANDU longrightarrow Passive Safe Reactor(PSR）longrightarrowFBR strategy should be also considered as a contingency for growing national concerns on nuclear safety and public acceptance deterioration in the future. FBR development and establishment of related fuel cycle should be started as soon as possible considering the uranium shortage anticipated between 2007 and 2032. It should be noted that the increasing use of nuclear energy to minimize the greenhouse effects in the early 21st century would accelerate the uranium resource depletion. The study also concludes that the current level of nuclear engineering professionals employment is not sufficient until 2010 for the establishment of nuclear infrastructure.

• Structural Engineering and Mechanics
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• v.62 no.2
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• pp.125-138
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• 2017

Reliability-based design optimization (RBDO) is a powerful tool for design optimization when considering probabilistic characteristics of design variables. However, it is often computationally intensive because of the coupling of reliability analysis and cost minimization. In this study, the concept of reliability mapping function is defined based on the relationship between the reliability index obtained by using the mean value first order reliability method and the failure probability obtained by using an improved response surface method. Double-loop involved in the classical RBDO can be converted into single-loop by using the reliability mapping function. Since the computational effort of the mean value first order reliability method is minimal, RBDO by using reliability mapping functions should be highly efficient. Engineering examples are given to demonstrate the efficiency and accuracy of the proposed method. Numerical results indicated that the proposed method has the similar accuracy as Monte Carlo simulation, and it can obviously reduce the computational effort.