• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.52.2-52
• /
• 2002

In this paper we consider an approach to a formal linearization for time-variant nonlinear systems. A time-variant nonlinear sysetm is assumed to be described by a time-variant nonlinear differential equation. For this system, we introduce a coordinate transformation function which is composed of the Chebyshev polynomials. Using Chebyshev expansion to the state variable and Laguerre expansion to the time variable, the time-variant nonlinear sysetm is transformed into the time-variant linear one with respect to the above transformation function. As an application, we synthesize a time-variant nonlinear observer. Numerical experiments are included to demonstrate the validity of...

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1903-1906
• /
• 2005

We proposed a new variant of correlation approach for ARMA model. The proposed method is is intended to make the current prediction error uncorrelated with the past one. In the investigation of the properties, the uniqueness, consistency and asymptotic normality of the estimate are shown. Via simulation results, we show that the proposed method give good estimates for various systems.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.05a
• /
• pp.328-332
• /
• 2006

소비자의 요구가 다양해지면서 많은 기업들이 관리해야 할 제품의 종류가 지난 몇 년간 급격히 늘어났다. 이에 한 제품에 대해 다양한 품목군을 유지해야 할 필요성이 제기되었으며, 전통적인 BOM(Bill of Material)으로 다양한 제품을 표현하기에는 막대한 양의 데이터가 발생하여 관리상의 어려움이 생기며, 데이터의 구성에도 중복성의 문제가 발생하게 되는 등의 한계가 드러남에 따라 다양한 제품군을 자체적으로 반영할 수 있는 Variant BOM의 개념 및 설계 방법론이 주목을 받고 있다. Variant BOM은 동일한 제품군에 대해 일부 구성품을 달리하여 구현한 다양한 제품을 반영하는 BOM의 한 종류로서 산업에서의 활용도가 높은 편이나, 여기에도 데이터의 중복성이나 Variant의 정도가 많아지면 관리에 어려움이 생기는 등의 몇 가지 단점을 내포하고 있다. 본 연구에서는 Variant Bill of Material을 대상으로 기존 연구들의 문제점을 분석하고 이를 해결하기 위하여 BOM에 좌표개념을 도입한 새로운 접근법을 제시한다. 이를 통해 BOM의 Structure와 Part를 분리시켰고, Linking Table을 통해 Structure와 Part를 연결하여 기존의 Variant BOM에 있던 문제들을 해결하였다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.8
• /
• pp.1986-1992
• /
• 2009

A user often searches a data by inputting a variant such as the abbreviation or substring of a word, or a misspelled word. The simple approach to the searching for variants is to build a variants dictionary. However, it entails enormous cost and time and can not handle variants by misspelling. Approximate searching, searching by approximate string matching, is a good approach to the searching. A problem in the approach is that it cannot handle variants by abbreviations. This paper propose a method for searching various variants including abbreviations and misspelled words, by using the trie indexing. First, this paper shows a variant matching method with the calculation of path weighted-metric. In addition, it provides variant searching algorithm to reduce the search time.

• Proceedings of the KSR Conference
• /
• 2000.05a
• /
• pp.250-257
• /
• 2000

A Helmholtz free energy for a martensitic transformation of a single crystalline shape-memory alloy is obtained by a micromechanical approach, 24 variants of the single crystal are taken into account. In the framework of irreversible thermodynamics, a kinetic relation, a martensitic nucleation criterion and the reorientation criterion of martensitic variants are obtained. These relations are valid for a three-dimensional proportional or non-proportional mechanical loading or a combination of mechanical and thermal loading. Reorientation behavior of a single crystalline shape-memory alloy CuZnAl is simulated. When a tensile load is applied to a thermally-induced martensite, 24 self-accommodated martensitic variants are reoriented to the most favorable variant. In the following unloading, the most favorable variant in the tensile load is reoriented to the most favorable variant in this loading condition.

• Computers and Concrete
• /
• v.17 no.4
• /
• pp.499-521
• /
• 2016

In this paper, a probabilistic- and finite element-based approach to evaluate and predict the lifetime performance of reinforced concrete (RC) bridges undergoing various maintenance actions is proposed with the time-variant system reliability being utilized as a performance indicator. Depending on their structural state during the degradation process, the classical maintenance actions for RC bridges are firstly categorized into four types: Preventive type I, Preventive type II, Strengthening and Replacement. Preventive type I is used to delay the onset of steel corrosion, Preventive type II can suppress the corrosion process of reinforcing steel, Strengthening is the application of various maintenance materials to improve the structural performance and Replacement is performed to restore the individual components or overall structure to their original conditions. The quantitative influence of these maintenance types on structural performance is investigated and the respective analysis modules are written and inputted into the computer program. Accordingly, the time-variant system reliability can be calculated by the use of Monte Carlo simulations and the updated the program. Finally, an existing RC continuous bridge located in Shanghai, China, is used as an illustrative example and the lifetime structural performance with and without each of the maintenance types are discussed. It is felt that the proposed approach can be applied to various RC bridges with different structural configurations, construction methods and environmental conditions.

• Korean Journal of Computational Design and Engineering
• /
• v.8 no.2
• /
• pp.101-108
• /
• 2003

Presented in this paper is the development of an product cost estimation system at the product design stage. The efficient cost estimation function at the design stage is essential for the cost reduction activities through the entire product life cycle. For this purpose, it is necessary to establish a systematic working procedure, and to develop information system for managing a great deal of production and product-related data required for the cost estimation. The developed system has the capability of estimating a cost of assembly type products as well as unit-item type products. As proposed system is based on the variant approach, it can be used easily at an early design stage without the need for detail design information. Also, this system is integrated with legacy PDM (Product Data Management) and ERP (Enterprise Resource Planning) system for fast. accurate and easy product cost estimation. The estimated cost includes material cost, overhead cost as well as labor cost.

• Journal of Korea Game Society
• /
• v.21 no.4
• /
• pp.109-116
• /
• 2021

In this paper, we considered that recently 3D game characters have been almost alike realistic expression because of a great mathematical computation and efficient techniques on GPU hardware. We presented the rendering technique and analysis for 3D game characters to simulate and render mathematical approach model from recent researches to perform the game engine for the surface reflection of lighting model. We compare our approach with the existing variant rendering techniques here using Open GL shader language on game engine. The experimental result will be provided the view-dependent visual appearance of variant and effective modeling characters for realistic expression using existing methods on the GPU for effective simulations and rendering process. Since there are many operations that are used redundantly while performing mathematical operations, the necessary functions and requirements have been to compute in advance.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.4
• /
• pp.1925-1931
• /
• 2016

Background: The XRCC1 protein facilitates various DNA repair pathways; single-nucleotide polymorphisms (SNPs) in this gene are associated with a risk of gastrointestinal cancer (GIC) with inconsistent results, but no data have been previously reported for the Sabah, North Borneo, population. We accordingly investigated the XRCC1 Arg194Trp and Arg399Gln SNPs in terms of GIC risk in Sabah. Materials and Methods: We performed genotyping for both SNPs for 250 GIC patients and 572 healthy volunteers using a polymerase chain reaction-restriction fragment length polymorphism approach. We validated heterozygosity and homozygosity for both SNPs using direct sequencing. Results: The presence of a variant 194Trp allele in the Arg194Trp SNP was significantly associated with a higher risk of GIC, especially with gastric and colorectal cancers. We additionally found that the variant 399Gln allele in Arg399Gln SNP was associated with a greater risk of developing gastric cancer. Our combined analysis revealed that inheritance of variant alleles in both SNPs increased the GIC risk in Sabah population. Based on our etiological analysis, we found that subjects ${\geq}50years$ and males who carrying the variant 194Trp allele, and Bajau subjects carrying the 399Gln allele had a significantly increased risk of GIC. Conclusions: Our findings suggest that inheritance of variant alleles in XRCC1 Arg194Trp and Arg399Gln SNPs may act as biomarkers for the early detection of GIC, especially for gastric and colorectal cancers in the Sabah population.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.8
• /
• pp.989-996
• /
• 2010

Statistical regression and/or interpolation models have been used for data analysis and response prediction using the results of the physical experiments and/or computer simulations in structural engineering fields. These models have been employed during the last decade to develop a variety of design methodologies. However, these models only handled responses with respect to space variables such as size and shape of structures and cannot handle time-variant dynamic responses, i.e. response varying with time. In this research, statistical space-time metamodels based on multiple response approach that can handle responses with respect to both space variables and a time variable are proposed. Regression and interpolation models such as the response surface model (RSM) and kriging model were developed for handling time-variant dynamic responses of structural engineering. We evaluate the accuracies of the responses predicted by the two statistical space-time metamodels by comparing them with the responses obtained by the physical experiments and/or computer simulations.