• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.4
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• pp.476-484
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• 2010

Precise positioning stages are often employed for precise machinery. For the purpose of vibration isolation, these precise positioning stages are mounted on a heavy base structure which is supported by compliant springs. Then the base structure is subjected to residual vibration due to the reactive force and vertical moving load induced by the stage motion. This paper investigates the vibration behavior of a positioning stage base and the associated vibration suppression technique. A dynamic model is developed to investigate the base vibration due to the reactive force and moving load effects by the moving stage. An input shaping technique is also developed to suppress the residual vibrations in base structures. Simulations and experiments show that the developed dynamic model adequately represents the base vibration and that the proposed input shaping technique effectively removes the residual vibrations from the positioning stage base.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.7
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• pp.653-667
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• 1990

Superconductor is consolidated, for required current capacity, with proper numbers of basic strands which are multifilamentary composites. Althouth superconductors are perfectly loss-free under DC conditions of current and field, AC losses occur under time-varying condition of the current and field. The AC losses are a controllable inherent characteristics of supercondectors. The AC losses dependent on the changing rate of current and field can be reduced by reducing the filament diameter. On the other hand, finer filament results in manufacturing cost increase. Therefore, in this paper optimization technique of superconductor for SMES is proposed from the viewpoint of AC loss reduction and manufacturing cost increase. The case study shows that the technique can be effectively used for the design of superconductor for SMES, appreciating the influence of various parameters related to superconductor itself and operating condition of SMES. As a result of the case study, it is confirmed that the technique is more effective for the design of superconductor for SMES for electric power power system stabilization rather then SMES for energy storage.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.86-91
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• 2022

The mechanical structures mounted on vehicles or aircrafts are subject to random accelerations, such as earthquakes, at the base, and their responses have been calculated through spectrum analysis. However, this method poses a challenge during the synthesis of the responses owing to the loss of the vibration phase. It is necessary to evaluate the time history results to obtain the exact responses; therefore, an efficient technique is proposed to solve this issue. The present technique involves constructing a superelement using the sub-structuring method and finding solutions for this superelement. The finite element model (FEM) was substituted by a superelement, which was simplified into one element with selected nodes. Comparing the numerical results of the superelement with the time history responses for the original finite element model, the two solutions agree well despite the fact that the computation time of the proposed technique has been greatly shortened.

• Journal of Information Technology Applications and Management
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• v.20 no.3_spc
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• pp.169-185
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• 2013

In this research, for find out how operations efficiency for ERP systems, after introducing ERP to manufacturing firms with DEA technique. According to research analyzed relative time dependent efficiency, using Time Window Analysis. And for company group and the other firm within the each same Industry, the relative effectiveness of each company group establishment was compared using DEA.

• Korean Management Science Review
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• v.26 no.2
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• pp.61-70
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• 2009

This study gives the quality factor evaluation of rubber gloves manufacturing, including a systematic classification of poor durability(internal quality factors) and look bad(external quality factors) as well as the types of defective items, along with the relationship between quality factors and the defective types. The relationship analysis between quality factors and the defective types are performed with AHP(Analytic Hierarchy Process) technique. The results of our study will be useful for quality management activities and manufacturing process in rubber gloves manufacturing companies.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.4
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• pp.97-103
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• 2009

Since a demand for an extensive range of earthmoving equipment like a hydraulic excavator with a capacity of 85tons has been asked in construction fields, a performance of its track drive unit has to be verified experimentally. Among the verification of the performances, a torque measurement is at issue, in which a torque meter is utilized widely. However, the very large scaled torque meter is necessary when a discharged torque from the track drive unit is increased significantly. In addition, the price for experimental set-up of a torque meter is too high due to its limitation of the geometry such as long length, and a break down in operation occurs frequently. In this study, to measure a high torque up to 200,000Nm, a new technique was proposed as an alternative of conventional measurement by using a torque meter. The new technique enables to measure the high torque stably in a compact space via a torque arm and two load cells. The experimental results showed a propriety of the proposed torque measuring technique for a track drive unit with very large capacity.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1012-1016
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• 2004

In this paper, we propose a simple but optimized NC code generating technique for disk cams by means of tool path error control in a five-axis CNC machining center. Using the geometric theorem of the triangle made between manufacturing points and error checkpoint, the tool path error has been studied for disk cams profile generation and an improvement in the profile has been obtained. Then, based on the present manufacturing approach a computer program is developed on $C^{++}$ language to perform and to verify the shape design, the manufacturing simulation, and the optimized generation of the NC code.

• Transactions of Materials Processing
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• v.12 no.2
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• pp.110-115
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• 2003

This paper is concerned with the compression test and forming process of flange by using virtual reality and analysis(simulation) program. This virtual manufacturing can be carried out one personal computer without any expensive devices for experiment. The virtual manufacturing composed of three modules such as the imput, calculation and the output modules on internet. Internet user can give the material's property and process parameters to the sever computer at the input module. On the calculation module, a simulator computes the virtual manufacturing process by analysis program and stores the data as a file. The output module is the program in which internet user can confirm virtual manufacturing results by showing tables, graphs, and 3D animation. This programs is designed by an internet language such as HTML, CGI, VRML and JAVA ,while analysis programs use the finite increasing, the virtual manufacturing technique will substitute many real experiments in the future.

• The KSFM Journal of Fluid Machinery
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• v.2 no.3 s.4
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• pp.30-36
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• 1999

Blade shape profile in the axial compressor is one of the most important factors governing its aerodynamic characteristics. Manufacturing tolerance, which is inevitable in the blade manufacturing processes, may change blade profile and as a consequence, it will affect the compressor performance. In this paper, influence of manufacturing tolerance on the aerodynamic characteristics of axial compressor blades with distortion of blade profile curvatures is investigated by using a flow simulation technique. It is found that manufacturing tolerance can be an important factor affecting the source of both profile and wake losses of the axial compressor blades.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.4
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• pp.33-39
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• 2010

Manufacturing accuracy of a precision instrument was essential to stability and efficiency of the product. Accordingly, geometrically accuracy management of precision instrument was very becoming the technique in order to design and manufacturing for machine. In this study, Measuring System is developed for extra long roller using non-contact sensor. Futhermore, It's studied by Geometric Tolerance. Exact roundness is obtained to Least Squares method from the reference circle of measured data. Measuring System is analyzed point of measurement and straightness of extra long roller is evaluated by FEM.