• Interaction and multiscale mechanics
• /
• v.3 no.3
• /
• pp.267-276
• /
• 2010

A nonlocal finite element model is developed for solving elasto-static frictional contact problems of nanostructures and nanoscale devices. A two dimensional Eringen-type nonlocal elasticity model is adopted. The material is characterized by a stress-strain constitutive relation of a convolution integral form whose kernel is capable to take into account both the diffusion process of nonlocal elasticity and the scale ratio effects. The incremental convex programming procedure is exploited as a solver. Two examples of different nature are presented, the first one presents the behavior of a nanoscale contacting system and the second example discusses the nano-indentation problem.

• Journal of applied mathematics & informatics
• /
• v.22 no.1_2
• /
• pp.373-385
• /
• 2006

To solve a class of nonlinear parameter estimation problems, a method combining the regularized structured nonlinear total least norm (RSNTLN) method and parameter separation scheme is suggested. The method guarantees the convergence of parameters and has an advantages in reducing the residual norm over the use of RSNTLN only. Numerical experiments for two models appeared in signal processing show that the suggested method is more effective in obtaining solution and parameter with minimum residual norm.

• Knowledge Management Research
• /
• v.13 no.2
• /
• pp.37-52
• /
• 2012

A spreadsheet is a office automation software which has been widely used in almost all areas in business. A spreadsheet is used for calculation, data analysis, model building and so on. As a result, spreadsheet is a very important tool for generating knowlege in a firm. Errors in a spreadsheet model can cause a serious financial damage in a corporation. However in Korea few researches for reducing errors have been performed. Neither serious efforts to reduce errors have been executed by corporations. In this research we provided summarized the results from a survey for spreadsheet usage, summarized researches on errors in spreadsheet up to now, and suggested a rules and structured development method for reducing errors in a spreadsheet. Errors in spreadsheets are prevalent. To solve this serious problem, we need much more attention on this problem in research area. Corporations must put more efforts on setting policies and rules. And also we need the government's concern and support.

• Communications for Statistical Applications and Methods
• /
• v.27 no.1
• /
• pp.79-95
• /
• 2020

The globalization of financial markets has broadened investment opportunities. International investors' investment portfolios consist of financial instruments from various countries; consequently, the risks associated with economic dependence among countries should be carefully considered. Step-down equity-linked securities (ELS) are a structured financial product that have recently become popular among Korean investors. Payoffs are based on two or three stock indices from different regions; therefore, dependence between the indices should be reflected in the risk analysis. In this study, we consider a regime-switching copula model to describe the joint behavior of two stock indices- the Eurostoxx50 and the Hang Seng China Enterprises Index (HSCEI). These indices are commonly used as underlying assets of step-down ELS. Using historical data, we analyze the risk associated with step-down ELS through the probabilities of early redemption. A regime-switching copula model can accommodate complicated dependence. Thus, it should be considered in the risk analysis of step-down ELS.

• Journal of Internet Computing and Services
• /
• v.7 no.5
• /
• pp.71-79
• /
• 2006

The GNUnet proposed a file encoding method by lKB block size to support anonymity of files and decentralizes encoded block to peers through unstructured model. but, the encoding and block decentralizing method with 600$\sim$700MB large multimedia file appeared two problems. First problem. it need addition R block and I block, which make about 4% of storage resource. Second problem, unstructured model added network load by broadcasting decentralizing method. This paper suggest variable encoding block size and structured model by block decentralizing solution. Suggested encoding method reduced block request supplementary block generation to 1% and network load by proposal structured model sending answer through dedicated peer to decentralize block.

• The Journal of Information Systems
• /
• v.15 no.4
• /
• pp.125-147
• /
• 2006

Internet shopping mall has dual nature of information technology features defined by the web-based application system and marketing features explained by the shopping marketplaces. The purpose of this study aims at analyzing the consumer's attempt to purchase and re-purchase intention to the internet shopping mall to combine the IT perspective and the marketing perspective. This paper develop the integrated research model with the acceptance behaviors of customers through consumer's purchase decision process(pre-purchase stage and post-purchase stage). The results from an empirical survey as follows: First, the integrated model is valid in predicting the acceptance of the internet shopping malls by using structured equation modeling. Second, there are the differences between pre-purchase stage and post-purchase stage by each conceptual constructs. Finally, the results of MSEM(Multi-group Structured Equation Modeling) indicate the perceived ease of use and perceived trust to the attitude to the internet shopping mall is more effectively predicted at the pre-purchase stage. Vice versa, the perceived usefulness to the intention to the purchase intention of internet shopping mall is more effectively predicted at the post-purchase stage. This study provides an integrative approach to develop the effective and successful internet shopping mall strategy.

• Journal of Intelligence and Information Systems
• /
• v.10 no.3
• /
• pp.27-37
• /
• 2004

XML has been proposed as a document standard for the representation and exchange of data on the WWW, and also becoming a standard for the search and reuse of scattered documents. When implementing a XML contents management system, special consideration should be imposed on how to model data and how to store the modelled data for effective and efficient management of the semi-structured data. In this paper, we proposed a new data model for the storage and search of XML document data. This proposed data model could represent both of data and structure views of XML documents, and be applied to the new data system for XML documents as well as the existing data systems.

• Proceedings of the Korean Nuclear Society Conference
• /
• 2004.05a
• /
• pp.173.1-173.1
• /
• 2004

• Proceedings of the Korean Society for Environmental Edudation Conference
• /
• 2003.12a
• /
• pp.107-124
• /
• 2003

• Journal of IKEEE
• /
• v.23 no.4
• /
• pp.1265-1272
• /
• 2019

We analyze the robustness of the existing predictor feedback controller for discrete-time linear systems with constant input delays against the structured model uncertainty. By modeling the constant input delay with a first-order PdE (Partial difference Equation), we replace the input delay with the PdE states. By applying a backstepping transformation, we build a target system that enables to construct an explicit Lyapunov function. Constructing the explicit Lyapunov function that covers the entire state variables, we prove the existence of an allowable maximum size of the structured model uncertainty to maintain stability and establish the robustness of the predictor feedback controller. The numerical example demonstrates that the stability of closed-loop system is maintained in the presence of the structured model uncertainty, and verifies the robustness of the predictor feedback controller.