• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1931-1942
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• 2002

In this paper a formulation of robust optimization is presented and illustrated by a design example of vibratory micro gyroscopes in order to reduce the effect of variations due to uncertainties in MEMS fabrication processes. For the vibratory micro gyroscope considered it is important to match the resonance frequencies of the vertical (sensing) and lateral (driving) modes as close as possible to attain a high sensing sensitivity. A deterministic optimization in which the difference of both the sensing and driving natural frequencies is minimized as an objective function results in highly enhanced performance but apt to be very sensitive to fabrication errors. The formulation proposed is to attain robustness of the performance by including the sensitivity of the response with respect to uncertain variables as a term of objective function to be minimized. This formulation is simple and practically applicable since no detail statistical information on fabrication errors is required. The geometric variables, beam width, length and thickness of vibratory micro gyroscopes are adopted as design variables and at the same time considered as uncertain variables because here occur the fabrication errors. A robustness test in terms of a percentage yield by using the Monte Carlo simulation has shown that the robust optimum produces twice more acceptable designs than the deterministic optimum. Improvement of robustness becomes bigger as the amount of fabrication errors is assumed larger. Considering that the magnitude of fabrication errors and uncertainties in a MEMS structure are comparatively large, the present method is illustrated to be a viable approach for a robust MEMS design.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.170-173
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• 2004

In this paper a web-based micro fabrication system is discussed. A commercial CAD and a web browser were used as its user interfaces. For the user interfaces, the concepts of Design for Manufacturing (DFM) were implemented providing the fabrication knowledge of micro machining to the designers. Simple databases were constructed to store the fabrication knowledge of materials, tools, and micro machining know-how. The part geometry was uploaded to the web server of this system as an STL (Stereo Lithography) format with process parameters for 3-axis micro milling. A Slice-based process planner automatically provides NC codes for controlling micro stages. A couple of micro parts were fabricated using the system with micro endmills. This design and manufacturing system enables network users to obtain micro-scale prototypes in a rapid manner.

• Korean Institute of Interior Design Journal
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• v.17 no.2
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• pp.150-161
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• 2008

It requires more close cooperation process and mediator for smooth communication in this industry structure where design and engineers are separated. The database of design integrates separate system and helps connection between organizations. The application category is utilized variously from formation to operation. Architectures addressed in this content as Frank Gehry and Nox are making differentiated design on the base of 3d digital methodology and using it widely from generation to fabrication. Especially they got to be free from the generative limit as it became available to analyse, digital surface organization, and realize the complex system form. Now more integrated and delicate works got to be affordable owing to various kinds of improved CNC, RP(rapid-prototype) machines, and architecture hardwares. With a linkage of software now at their disposal, architects can create a digital model of a building and all of its design elements, and in turn use this 3d information to construct actual building components using machines driven by CNC and other advanced manufacturing techniques. Digital technologies are enabling a direct correlation between what design and construction, thus bringing to the forefront the issue of the significance of information, the production, communication, application, and control of digital information in the industrial system. The central requirement is the clear, reliable, and consistent exchange of information among all parties involved in creating a given project.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.2
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• pp.178-182
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• 2011

Generally in order to reduce the steel weight of stiffened plate, stiffener spaces tend to be narrow and the plate gets thin. However, it will involve more fabrication cost because it can lead to the increase of welding length and the number of structural members. In the yard, the design which is able to reduce the total fabrication cost is needed, although it requires more steel weight. The purpose of this study is to find optimum stiffener spaces to minimize the fabrication cost for the cargo tank of LPG Carriers. Global optimization methods such as ES(Evolution Strategy) and GA(Genetic Algorithm) are introduced to find a global optimum solution and the sum of steel material cost and labor cost is selected as main objective function. Convergence degree of both methods in according to the size of searching population is examined and an efficient size is investigated. In order to verify the necessity of the optimum design based on the cost, minimum weight design and minimum cost design are carried out.

• Journal of Korean Association for Spatial Structures
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• v.23 no.3
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• pp.25-28
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• 2023

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.62-67
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• 2001

• Journal of KIBIM
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• v.5 no.2
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• pp.12-18
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• 2015

Bridge piers typically have circular or rectangular shapes without decorative design. Prefabrication for accelerated construction has been widely adopted in bridge structures. Cost for steel formwork is a main restriction of creative irregular shapes. 3D modelling techniques allow creative design of columns and 3D printing provides possibility to minimize the fabrication cost. In this paper, 3D design process of bridge piers was suggested by converting 2D picture into 3D decorative shape. Formwork design using 3D printed panels was also proposed and mock-up tests were conducted. Precast columns need accurate geometry control from fabrication to assembly. Laser scanning and geometry control devices were adopted. Through the digitalized process of design, fabrication and assembly, creative design of structures can be realized in reasonable cost range.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.851-856
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• 2005

The precision fabrication of aspherical lenses is increasingly required for the latest applications of compact and high resolution video-recording or camera systems. Micro-optical components, including micro-spherical or aspherical lenses and reflecting mirrors, are generally required to be manufactured with high shape accuracy, extremely low surface roughness and no surface damage. To meet the needs of the precision fabrication system, a bed which supports the micro aspherical lens fabrication machines stably and safely is required. In this study, the thickness of the ribs of the bed is optimized using the CAD integrated optimal design system, a virtual DS program.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.4
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• pp.44-50
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• 1985

This paper describes the design and fabrication of an integrated circuit which controls the phase of VTR servo systems. The integrated circuit was designed using 6#m design rule and its chip size is 3.6$\times$3.55mm$^2$. On the other hand it was fabricated using SBC, analog-compatible 12 L and double layer metal fabrication process technology. As a result, we succeeded in fabrication of If which satisfied D. C. characteristics and phase control function.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.114-116
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• 2001

This paper deals with the design and fabrication of loop superconducting Persistent Current Switch(PCS) circuit. The self and mutual inductances of the circuits are calculated and compared to the measured values. The size of loop circuits was determined using the calculated inductances, and the fabrication processes of the superconducting persistent current switch are described.