• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.858-860
• /
• 2005

This paper presents an Optimal Power Flow (OPF) algorithm using Interior Point Method (IPM) to swiftly and precisely perform the five minute dispatch. This newly suggested methodology is based on Affine Scailing Interior Point Method (AS IPM), which is favorable for large-scale problems involving many constraints. It is also eligible for OPF problems in order to improve the calculation speed and the preciseness of its resultant solutions. Lastly, this paper provides a relevant case study to confirm the efficiency of the proposed methodology.

• Proceedings of the KIEE Conference
• /
• 2005.11b
• /
• pp.156-158
• /
• 2005

This paper presents an Optimal Power Flow (OPF) algorithm using Interior Point Method (IPM) to swiftly and precisely perform the five minute dispatch. This newly suggested methodology is based on Affine Sealing Interior Point Method (AS IPM), which is favorable for large-scale problems involving many constraints. It is also eligible for OPF problems in order to improve the calculation speed and the preciseness of its resultant solutions. Big-M Method is also used to improve the solution stability. Finally, this paper provides a relevant case study to confirm the efficiency of the proposed methodology.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.32 no.3
• /
• pp.178-187
• /
• 2009

Six Sigma emphasizes KPI and establishes the present level as well as the goal level through statistical calculation and tries to achieve management innovation through process improvement. But in the area of new product development or service, sufficient data for statistical measurement may not be secured. On the other side, looking for contradictions through problem analysis, TRIZ is a methodology that stresses the process of solving these problems. TRIZ also has its own problems: it is hard to define its initial task, to objectify the measurement of effect, and to optimize the drawn out idea. The purpose of this report is to give a comprehensive understanding about each methodology (Sigma Six and TRIZ) through its analysis, to confirm the need of linking both methodologies, and to suggest a model for this linking process. Also, they will be verified through examples, and the synergy effect will be discussed.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.4
• /
• pp.118-124
• /
• 1998

The die wear is one of the main factors affecting die accuracy and tool lifetime. It is desired to reduce die wear by developing simulation method to predict wear based on process variables, and then optimizing the process. Therefore, this paper describes methodology of preform design for minimizing wear of finisher die in multi-stage cold forging processes. The finite element method is combined with the routine of wear prediction. The cold forging process is analyzed using developed simulation method. In order to obtain preform to minimize die wear, the Flexible Polyhedron Search(FPS) algorithm is used. The optimal preform shape is found from iterative deformation analysis and wear calculation.

• International Commerce and Information Review
• /
• v.9 no.1
• /
• pp.3-21
• /
• 2007

The explosive growth of e-marketplace transactions requires an appropriate trust measuring framework to protect involving transacting entities such as buyers and sellers. As a strategic competitive edge, e-marketplace service providers have been adopting various system features that make sure no one transacting entity takes a major risk in online transactions involved. In this paper, an improved trust measuring method using fuzzy theory for an e-marketplace is proposed. The proposed methodology incorporates fuzzy set and calculation concepts to help build trust matrices and models, which are used to measure the level of risk involved in a specific e-marketplace transaction concerned. The proposed framework can be utilized to optimize the transaction costs by recommending a differentiated transaction process according to the risk level involved in each online transaction.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.728-730
• /
• 2004

Transmission congestion is one of the Key factors to local market power in competitive electricity markets. Other players' strategy is also considered. This paper presents an alternative methodology in market power under transmission congestion and other players' strategy. The proposed methodology was demonstrated with the Optimal Power Flow(OPF). Case study is fulfilled by GAMS simulation.

• Journal of Power System Engineering
• /
• v.11 no.3
• /
• pp.9-15
• /
• 2007

This paper provides a methodology for the optimization of waste heat usage in Jeju Province. The incineration plant was considered as heat source and the food garbage plant and the youth hostel were selected as heat sink of this study. The distribution of the reusing energy in incineration plant is decide by load analysis and numerical calculation of the operational methodology. The main objective of this study is on the reduction of the fuel costs and reuse of waste heat. As the results, the efficiency of the incineration plant and two heat sink, the food garbage plant and the youth hostel, are improved and economical suggestions are proposed through the optimization analysis.

• Smart Structures and Systems
• /
• v.4 no.2
• /
• pp.171-182
• /
• 2008

In this paper, a methodology for the estimation of masonry elasticity and shear moduli is presented, for linear elasticity considerations. The methodology is based on the assumption that for a "periodic" masonry wall, which is formed by the repetition of a basic unit containing blocks and mortar, the mechanical characteristics of the unit are representative of the characteristics of the entire wall. For their calculation, the finite element analysis method is used. A micro-model with finite elements simulating separately the blocks and the mortar is developed. An equivalent finite element model, using an homogenous material is also developed and assuming equivalence of strains for the two models, the homogenous material properties are estimated. The efficiency of the method and its applicability limits are investigated.

• Journal of Energy Engineering
• /
• v.23 no.4
• /
• pp.215-222
• /
• 2014

A theory-based methodology for describing the thermodynamic properties of molecular nitrogen is presented. The results obtained indicate a successful application of a fully consistent statistical method for the description of a molecular system in different phase states. The method employs a density of states equation for solid nitrogen and a perturbation potential for gaseous and liquid nitrogen. The main characteristics of the calculation method include the need for a minimal number of initial data and the absence of fitting parameters. The adequacy of the physical model that is the basis for the method allows a description of existing experimental data and the peculiarities of the thermodynamic properties.

• Journal of Welding and Joining
• /
• v.31 no.3
• /
• pp.54-59
• /
• 2013

Several methodologies analyzing welding distortions of large shell structures like ship blocks have been developed and utilized in shipyards for a long times ago. In general, one of objects of thermal distortion analysis is to find welding sequence making least-deformation without any suppliance, and it can be solved easily and rapidly by EP strain-boundary method. But after assembly construction, there are usually more than 10 weldments in each process, and the number of sequence will follow the Factorial calculation. In this research, a method has been suggested to decide the best welding sequence by minimum analysis. Using this method, welding deformation could be reduced just analyzing some cases as many as the number of weldments. Experiments and Analysis of all cases were also done, and their best results are good agreements with predictation by suggested methodology.