• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1452-1460
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• 2001

A new method of parameter determination in the fatigue residual strength degradation model is proposed. The new method and minimization technique is compared experimentally to account for the effect of tension-compression fatigue loading of spheroidal graphite cast iron and graphite/epoxy laminate. It is shown that the correlation between the experimental results and the theoretical prediction on the fatigue life and residual strength distribution using the proposed method is very reasonable. Therefore, the proposed method is more adjustable in the determination of the parameter than minimization technique for the prediction of the fatigue characteristics.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.8
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• pp.351-357
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• 2005

This paper presents vibration minimization of a PMLSM driven feed-slide by using optimized smooth velocity curve with finite jerk. First of all, the PMLSM was designed and made to reduce detent force. Next, a PMLSM driven feed-slide system was mathematically modeled as a 4-degree-of-freedom lumped parameter model. The key idea of our vibration minimization method is to find out the most appropriate smooth velocity(feedrate) curve with finite jerk. The validity of our proposed method has been verified by comparing computer simulation results of the feed-slide model with experimental ones.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.705-710
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• 2011

This paper proposes establishment of generator maintenance scheduling(GMS) considering minimization of $CO_2$ emissions. The objective function model to minimize $CO_2$ emissions is used in this paper. In this paper, and also, GMS is established due to freedom of GMS of generators owned by a designated generation company. The practicality and effectiveness of the proposed approach are demonstrated by simulation studies for a real size power system model in Korea in 2010.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.5
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• pp.266-274
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• 2004

This paper presents a scheme for the interconnection of dispersed generator systems(DGs) based on load .unbalance and load model in composite distribution systems. Groups of each individual load model consist of residential, industrial, commercial, official and agricultural load. The unbalance is involved with many single-phase line segment. . Voltage profile improvement and system loss minimization by installation of DGs depend greatly on how they are placed and operated in the distribution systems. So, DGs can reduce distribution real power losses and replace large-scale generators if they are placed appropriately in the distribution systems. The main idea of solving fuzzy goal programming is to transform the original objective function and constraints into the equivalent multi-objectives functions with fuzzy sets to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithm. The method proposed is applied to IEEE 13 bus and 34 bus test systems to demonstrate its effectiveness.

• Structural Engineering and Mechanics
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• v.28 no.6
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• pp.677-694
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• 2008

A vibration power minimization model is developed, based on the mobility matrix method, for a vibration isolation system consisting of a vibrating source placed on an elastic support structure through multiple resilient mounts. This model is applied to investigate the design optimization of an X-Y motion stage-based vibration isolation system used in semiconductor wire-bonding equipment. By varying the stiffness coefficients of the resilient mounts while constraining the dynamic displacement amplitudes of the X-Y motion stage, the total power flow from the X-Y motion stage (the vibrating source) to the equipment table (the elastic support structure) is minimized at each frequency interval in the concerned frequency range for different stiffnesses of the equipment table. The results show that when the equipment table is relatively flexible, the optimal design based on the proposed vibration power inimization model gives significantly little power flow than that obtained using a conventional vibration force minimization model at some critical frequencies. When the equipment table is rigid enough, both models provide almost the same predictions on the total power flow.

• Journal of Korea Multimedia Society
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• v.6 no.6
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• pp.968-976
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• 2003

In this paper, we propose a novel method for lip recognition. Lip model is built based on the concatenated gray level distribution model, and the recognition problem is simplified as the minimization problem of matching object function. The Down Hill Simplex Algorithm is used for the minimization with the proposed novel method for setting initial condition, which can refrain Iteration from converging to local minima. The proposed algorithm shows extracting lip shape from the test image where Active Shape Model fails.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.87-96
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• 2016

The multinomial logit model, based on random utility maximization (RUM) theory, has been the predominant model used in travel mode choice contexts. In this paper, the travel mode choice model based on random regret minimization (RRM) theory is proposed as an alternative to the RUM model, and the applicability of the RRM model is examined. The presented model is applied to the case of inter-city travel mode choice in Korea. The empirical results show that the RUM model and RRM model have parameters that are consistent with the intuition. The goodness of fit statistics in the RRM model improved compared with the results of the RUM model. Consequently, these results show the possibility of using the RRM model in the context of travel mode choice.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.660-667
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• 2003

In this study, a Multiple Objective Mixed Integer Programming (MOMIP) Model is developed for sewer rehabilitation planning by considering cost, inflow/infiltration. A sewer rehabilitation planning model is required to decide the economic life of the sewer by considering trade-off between cost and inflow/infiltration. And it is required to find the optimal rehabilitation timing, according to the cost effectiveness of each sewer rehabilitation within the budget. To develop such a model, a multiple objective mixed integer programming model is formulated based on network flow optimization. The network is composed of state nodes and arcs. The state nodes represent the remaining life and the arcs represent the change of the state. The model consider multiple objectives which are cost minimization and minimization of inflow/infiltration. Using the multiple objective optimization, the trade-off between the cost and inflow/infiltration is presented to the planner so that a proper sewer rehabilitation plan can be selected.

• Journal of Korean Society for Quality Management
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• v.13 no.1
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• pp.56-64
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• 1985

This paper presents a general algorithm of multi-item continuous review models to obtain simultaneous solutions for ordering quantities and reorder points for each item in an inventory, while satisfying constraints on average inventory investment and reordering workload. Two models are formulated'in each model the heuristic method is utilized, and the partial back-logging is considered. In the first model, the objective function is the minimization of total inventory variable cost. In the second model, the objective function is the minimization of total time-weighted shortages, and the ordering, holding, and stockout costs in this model are independent each other. A numerical example is also solved to present application of each model.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.7
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• pp.743-751
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• 2013

In this paper, an approach to deal with model uncertainty using norm-optimal iterative learning control (ILC) is mentioned. Model uncertainty generally degrades the convergence and performance of conventional learning algorithms. To deal with model uncertainty, a worst-case norm-optimal ILC is introduced. The problem is then reformulated as a convex minimization problem, which can be solved efficiently to generate the control signal. The paper also investigates the relationship between the proposed approach and conventional norm-optimal ILC; where it is found that the suggested design method is equivalent to conventional norm-optimal ILC with trial-varying parameters. Finally, simulation results of the presented technique are given.