• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1558-1564
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• 2019

Corporate business clusters create a borderless business network through value chains and value creation activities. Clusters in the IT sector are crossing regional boundaries because of their rapid technological development and short product life cycle. To investigate this phenomenon, we examined the value activities of IT companies. As a result, the global expansion of the case companies was limited, but they had business clusters that exceeded the regional boundaries. However, because the order of business clusters is not advanced, value activities are focused on productivity rather than innovation. Given the rapidly evolving nature of IT, it is necessary to evolve into a business cluster that can create new value. Companies must design and implement value-creating processes to develop new technologies or enter new markets, which can lead to cluster growth. Companies must design and implement value-creating processes to develop new technologies or enter new markets, which can lead to cluster growth.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.4
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• pp.199-208
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• 2023

Taguchi method is one of the most popular approaches for design optimization such that performance characteristics become robust to uncontrollable noise variables. However, most previous Taguchi method applications have addressed a single-characteristic problem. Problems with multiple characteristics are more common in practice. The multi-criteria decision making(MCDM) problem is to select the optimal one among multiple alternatives by integrating a number of criteria that may conflict with each other. Representative MCDM methods include TOPSIS(Technique for Order of Preference by Similarity to Ideal Solution), GRA(Grey Relational Analysis), PCA(Principal Component Analysis), fuzzy logic system, and so on. Therefore, numerous approaches have been conducted to deal with the multi-characteristic design problem by combining original Taguchi method and MCDM methods. In the MCDM problem, multiple criteria generally have different measurement units, which means that there may be a large difference in the physical value of the criteria and ultimately makes it difficult to integrate the measurements for the criteria. Therefore, the normalization technique is usually utilized to convert different units of criteria into one identical unit. There are four normalization techniques commonly used in MCDM problems, including vector normalization, linear scale transformation(max-min, max, or sum). However, the normalization techniques have several shortcomings and do not adequately incorporate the practical matters. For example, if certain alternative has maximum value of data for certain criterion, this alternative is considered as the solution in original process. However, if the maximum value of data does not satisfy the required degree of fulfillment of designer or customer, the alternative may not be considered as the solution. To solve this problem, this paper employs the desirability function that has been proposed in our previous research. The desirability function uses upper limit and lower limit in normalization process. The threshold points for establishing upper or lower limits let us know what degree of fulfillment of designer or customer is. This paper proposes a new design optimization technique for multi-characteristic design problem by integrating the Taguchi method and our desirability functions. Finally, the proposed technique is able to obtain the optimal solution that is robust to multi-characteristic performances.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.81-90
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• 1993

The optimum design of a structure requires the determination of the economical member size and shape of the structure which satisfies the design condition and function. In this study, the process of design automatization of three-dimensional truss structure introduces the optimization technique tests its application in the design automatization, proposes its application method and applies the example structure of the parabolic antenna truss. Using the Formex Algebra of configuration function, the structure's mesh-generation is automatized. By using the program developed in this study, the input member array, member size and load condition designer can generate the input data file for the structure analysis and optimum design. This study is aimed at the development of a design automatization system that search for tile optimum value of a structure design by observing the structure's sensitivity from the modification of member array and member property.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.181-186
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• 2004

In gradient based optimization methods, the finite differencing which uses small perturbations in the design variables has been used to calculate the sensitivity. Recently, the automatic differentiation has been widely studied to calculate the function value and the sensitivities simultaneously. In this paper, the applicability of the automatic differentiation In the aerodynamic design optimization is studied. ADIFOR and TAPENADE are used to generate the codes which give the function value and the sensitivities for 2D compressible inviscid flows.

• Earthquakes and Structures
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• v.8 no.6
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• pp.1349-1362
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• 2015

This paper presents an analytical study aimed at evaluating the effectiveness of using buckling-restrained braces (BRBs) in mitigating the seismic response of a case study 6 storey reinforced concrete (RC) building. In the design of the BRBs with non-prismatic cross-sections, twelve combinations of ${\alpha}$ and ${\beta}$ design parameters that influence the strength and stiffness of the BRBs, respectively, were considered. The response of the structure with and without BRBs under earthquake ground accelerations were evaluated through nonlinear dynamic analysis. Two sets of ground motions representative of the design earthquake with 10% and 50% exceedance probability in fifty years were taken into account. By comparing the structural performance of the original and buckling restrained braced structures, it was observed that the use of the BRBs were very effective in mitigating the seismic response as a retrofit scheme. However, the selection of the strength and stiffness parameters of the BRBs had considerable effect on the response characteristics of RC structures. For instance, by increasing the value of ${\alpha}$ and by decreasing the value of ${\beta}$ of the buckling-restrained braces, the maximum deformation demand of the structures increased.

• Journal of Power Electronics
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• v.16 no.3
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• pp.832-839
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• 2016

In this study, the performance of a direct current (DC)-DC buck converter is analyzed in the presence of non-idealities in passive components and semiconductor devices. The effect of these non-idealities on the various design issues of a DC-DC buck converter is studied. An improved expression for duty cycle is developed to compensate the losses that occur because of the non-idealities. The design equations for inductor and capacitor calculation are modified based on this improved expression. The effect of the variation in capacitor equivalent series resistance (ESR) on output voltage ripple (OVR) is analyzed in detail. It is observed that the value of required capacitance increases with ESR. However, beyond a maximum value of ESR (r_c,max), the capacitor is unable to maintain OVR within a specified limit. The expression of r_c,max is derived in terms of specified OVR and inductor current ripple. Finally, these theoretical studies are validated through MATLAB simulation and experimental results.

• Structural Engineering and Mechanics
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• v.53 no.6
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• pp.1127-1141
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• 2015

The optimum design of liquid column dampers in seismic vibration control considering system parameter uncertainty is usually performed by minimizing the unconditional response of a structure without any consideration to the variation of damper performance due to uncertainty. However, the system so designed may be sensitive to the variations of input system parameters due to uncertainty. The present study is concerned with robust design optimization (RDO) of liquid column vibration absorber (LCVA) considering random system parameters characterizing the primary structure and ground motion model. The RDO is obtained by minimizing the weighted sum of the mean value of the root mean square displacement of the primary structure as well as its standard deviation. A numerical study elucidates the importance of the RDO procedure for design of LCVA system by comparing the RDO results with the results obtained by the conventional stochastic structural optimization procedure and the unconditional response based optimization.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.604-607
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• 2002

In this study, we will try to develop the 3D automatic design program of limit gauge. When users, who have some mechanical information, input some date, they can do 3D-modeling easily like expert. This is one of the merit in automatic design program and the automatic design program can compare the limit gauge made in this study with processed the bolt and nut model. This demonstrates the effective value of automatic design model. Limits gauge of sort divide into ring gauge of measuring bolt and pin gauge of measuring nut. The new automatic design program follows the KS.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.595-599
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• 2002

In this study, we try to develop the 3D automatic design program of screw thread limit gauge. When users, who have some mechanical information, input some date, they can do 3D-modeling easily like expert. This is one of the merit in automatic design program and the automatic design program can compare screw thread limit gauge made in this study with processed the bolt and nut model. This demonstrates the effective value of automatic design model. Screw thread limit gauge of sort divide into ring gauge of measuring bolt and pin gauge of measuring nut. The new created automatic design program follows the KS.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.5
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• pp.17-22
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• 2019

In this study, Cermet Reamers for planet carrier was manufactured and the machining characteristics were analyzed through processing experiment. Cermet reamer with ∅14, ∅15, ∅18, and ∅21mm was used and machining characteristics were compared and analyzed by observing tool wear, machining hole dimensions and surface roughness. In the flank wear of the tool, the result is less than 0.2mm, which is the target value for each tool size. The experimental results of the machining hole dimensions show the results of the process control range of 3/100 or less according to the size of the tool. Also, the surface roughness measurement result showed a value of less than $0.5{\mu}m$ in the process control range for each tool size. As a result of observing the experimental results of each ∅, the results satisfied the process standard in both the tool wear, the machining hole dimension and the surface roughness.