• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1408-1415
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• 2002

In this paper, we investigate the effect and the importance of the accuracy of finite element analysis in the shape optimization based on the finite element method and improve the existing finite element which has inaccuracy in some cases. And then, the shape optimization is performed by using the improved finite element. One of the main stream to improve finite element is the prevention of locking phenomenon. In case of bending dominant problems, finite element solutions cannot be reliable because of shear locking phenomenon. In the process of shape optimization, the mesh distortion is large due to the change of the structure outline. So, we have to raise the accuracy of finite element analysis for the large mesh distortion. We cannot guarantee the accurate result unless the finite element itself is accurate or the finite elements are remeshed. So, we approach to more accurate shape optimization to diminish these inaccuracies by improving the existing finite element. The shape optimization using the modified finite element is applied to a two and three dimensional simple beam. Results show that the modified finite element has improved the optimization results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.803-809
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• 2000

For the effective analysis of an engineering problem, meshless methods which require only positioning finite points without the element meshing recently have been proposed and being studied extensively. Meshless methods have difficulty in imposing essential boundary conditions directly, because non-interpolate shape functions originated from an approximation process are used. So some techniques, which are Lagrange multiplier method, modified variational principles and coupling with finite elements and so on, were introduced in order to impose essential boundary conditions. In spite of these methods, imposition of essential boundary conditions have still many problems like as non-positive definiteness, inaccuracy and negation of meshless characteristics. In this paper, we propose a new method which modifies shape function. Through numerical tests, convergence, accuracy and validity of this method are compared with the standard EFGM which uses Lagrange multiplier method or modified variational principles. According to this study, the proposed method shows the comparable accuracy and efficiency.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.1
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• pp.73-93
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• 2012

The primary objective of this research is to explain how to implement the Service Oriented Architecture (hereafter SOA) enabled Enterprise Resource Planning (hereafter ERP) system successfully for service industries. An implementation of the ERP system help many organizations to alleviate the difficult job of supporting inflexible or legacy systems that in most cases result in cost increases, data redundancy and inaccuracy, and various inefficiencies. However, the ERP system is losing its market share rapidly to the cloud computing system which utilizes the Software-as-a-service (hereafter SaaS) and SOA. The SOA is an approach to integrate various types of IT resources to leverage existing ERP system, while at the same time building an infrastructure that can readily respond to new business environment and offer new dynamic applications. The companies that implement this system have less of a need for the kinds of all-in-one ERP system that have dominated the back office for decades and can move freely to best-of-breed applications. This research will identify the benefits and costs of the SOA enabled ERP system through case studies and its impact on competitive priorities such as cost, quality, delivery, and flexibility.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.4
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• pp.213-221
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• 2017

Utilizing the existing polishing robot prevents unrestricted change of direction, driving, and identification of driving pathway. To overcome this barrier, driving mechaism has been designed with Omniwheels with encoders and RSSI method of beacon system has been utilized to identify the driving path by position recognition. Due to the wheel characteristics, the Omniwheel mobile robot generates greater slip than the conventional mobile robot, which reduces its driving accuracy. Therefore, to improve the driving accuracy, the localization is conducted through the fusion of encoder and RSSI of beacon data to compensate for the errors caused by Dead Reckoning and inaccuracy of sensors. Finally, the localization accuracies of the proposed and conventional indoor localization method are compared to show effectiveness of the proposed driving control for a polishing robot.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.2
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• pp.123-131
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• 2005

According to ow previous study, we confirmed That the Petrov-Galerkin natural element method(PG-NEM) completely resolves the numerical integration inaccuracy in the conventional Bubnov-Galerkin natural element method(BG-NEM). This paper is an extension of PG-NEM to two-dimensional geometrically nonlinear problem. For the analysis, a linearized total Lagrangian formulation is approximated with the PS-NEM. At every load step, the grid points ate updated and the shape functions are reproduced from the relocated nodal distribution. This process enables the PG-NEM to provide more accurate and robust approximations. The representative numerical experiments performed by the test Fortran program, and the numerical results confirmed that the PG-NEM effectively and accurately approximates The large deformation problem.

• East Asian Journal of Business Economics (EAJBE)
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• v.7 no.1
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• pp.17-25
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• 2019

Purpose - The international market provides a growth momentum for firms by allowing them to tap into a new market. Given information asymmetry between firms and financial analysts, firms' international growth can be perceived as a higher business prospect by analysts. This paper explores the possibility of analysts' over-emphasis on foreign income growth in predicting earnings. Research design, data, and methodology - We utilize a sample of U.S. firms to test the relationship between foreign income growth and analysts' forecast optimism. Our sample of publicly listed and traded U.S. firms between 1976 and 2016 consists of 6,120 firm-year observations. Results - Empirical analyses show that firms that show higher international growth in earnings are likely to face forecast inaccuracy by financial analysts. From the perspective of firms, their earnings are less than what analysts forecasted. Contrary to our prediction on the moderating effect of innovative capabilities, optimistic bias is not intensified - rather, it is reduced - when firms have higher innovative capabilities. Conclusions - Our results imply that while analysts favor firms with higher international growth, innovative capability on the international market places additional risks to firms' operation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.46-46
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• 2017

We developed a rice simulation model for remote-sensing (SIMRIW-RS, Homma et al., 2007) to evaluate rice production and management on a regional scale. Here, we reports its application trial to estimate rice production in farmers' fields in Sendai, Japan. The remote-sensing data for the application was periodically obtained by multispectral camera (RGB + NIR and RedEdge) attached with unmanned air vehicle (UAV). The airborne images was 8 cm in resolution which was attained by the flight at an altitude of 115 m. The remote-sensing data was relatively corresponded with leaf area index (LAI) of rice and its spatial and temporal variation, although the correspondences had some errors due to locational inaccuracy. Calibration of the simulation model depended on the first two remote-sensing data (obtained around one month after transplanting and panicle initiation) well predicted rice growth evaluated by the third remote-sensing data. The parameters obtained through the calibration may reflect soil fertility, and will be utilized for nutritional management. Although estimation accuracy has still needed to be improved, the rice yield was also well estimated. These results recommended further data accumulation and more accurate locational identification to improve the estimation accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.349-356
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• 2011

This paper replaces a conventional austenitic stainless steel sheet to a ferritic stainless steel for the cost reduction of a pulsator cover of a washing machine. However, ferritic stainless steel has poor formability in comparison with austenitic one. The low formability of ferritic steel results in problems during stamping such as fracture, wrinkling, shape inaccuracy and so on. Design modification of the stamping tool is carried out with the aid of the finite element analysis for multistage stamping process of the pulsator cover. The simulation results show that fracture occurs on top of the product while wrinkles are generated by the excess metal near the wing part. Modification of the initial stamping die is performed to improve metal flow and to eliminate problems during the stamping process. Simulation with the modified design fully demonstrates that safe forming is possible without inferiorities.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.06a
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• pp.99-102
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• 2006

In the present study, the blow forming characteristics of AZ31 sheet was investigated to test the feasibility of the practical application of wrought Mg alloys. Mg alloys have drawn a huge attention in the field of transportation and consumer electronics industries since it is the lightest alloy which could be industrially applicable. Most Mg alloy components have been fabricated by casting method. However, there have been a lot of research activities on the wrought alloys and their plastic forming process recently. Shallow cups for the small electronics cases have been stamped with warm die system. However, some technical issues will challenge Mg forming when large parts are considered with warm die system over $200^{\circ}C$. Most of all, thermal expansion of die system will deteriorate a die accuracy. On the other hand, blow forming does not have a problem with inaccuracy with die system. In this study, tensile tests were followed by blow forming at various temperature and pressure. AZ31 sheet showed a superplastic deformation behavior with extensive grain boundary sliding at the temperature above $300^{\circ}C$. However, the deformation behavior was likely to differ depending on stress condition.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.2
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• pp.95-100
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• 2006

The GaAs-on-insulator (GOI) wafer fabrication technique has been developed by using ion-cut process, based on hydrogen ion implantation and wafer direct bonding techniques. The hydrogen ion implantation condition for the ion-cut process in GaAs and the associated implantation mechanism have been investigated in this paper. Depth distribution of hydrogen atoms and the corresponding lattice disorder in (100) GaAs wafers produced by 40 keV hydrogen ion implantation were studied by SIMS and RBS/channeling analysis, respectively. In addition, the formation of platelets in the as-implanted GaAs and their microscopic evolution with annealing in the damaged layer was also studied by cross-sectional TEM analysis. The influence of the ion fluence, the implantation temperature and subsequent annealing on blistering and/or flaking was studied, and the optimum conditions for achieving blistering/splitting only after post-implantation annealing were determined. It was found that the new optimum implant temperature window for the GaAs ion-cut lie in $120{\sim}160^{\circ}C$, which is markedly lower than the previously reported window probably due to the inaccuracy in temperature measurement in most of the other implanters.