• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.727-731
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• 2000

This paper presents a new practical autopilot design approach to acceleration control for tail-controlled STT(Skid-to-Turn) missiles. The approach is novel in that the proposed parametric affine missile model adopts acceleration as th controlled output and considers the couplings between the forces as well as the moments and control fin deflections. The aerodynamic coefficients in the proposed model are expressed in a closed form with fittable parameters over the whole operating range. The parameters are fitted from aerodynamic coefficient look-up tables by the function approximation technique which is based on the combination of local parametric models through curve fitting using the corresponding influence functions. In this paper in order to employ the results of parametric affine modeling in the autopilot controller design we derived a parametric affine missile model and designed a feedback linearizing controller for the obtained model. Stability analysis for the overall closed loop sys-tem is provided considering the uncertainties arising from approximation errors. the validity of the proposed modeling and control approach is demonstrated through simulations for an STT missile.

• Journal of Digital Convergence
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• v.13 no.1
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• pp.93-110
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• 2015

The purpose of this study is to identify the role of T-shaped skill between customer/supplier network and innovation performance of firms. To manage effectively the relationship between collaborative firms, firms need to have a prior related knowledge. The premise of absorptive capacity is that the organization needs prior related knowledge to recognize, assimilate, and apply new knowledge. In this context, T-shaped skill facilitates the learning of new related knowledge. The skill is thus a critical component of innovative capabilities. We found that T-shaped skill plays a mediating role in the relationship between networks and innovation performance. The conclusions and implications are discussed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.512-515
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• 2010

본 논문에서는 등기하 해석법을 이용하여 설계의존형 하중조건을 갖는 구조물에 대한 형상 최적설계를 수행하였다. 유한요소법 기반 형상 최적설계는 CAD 모델과 해석 모델의 차이로 인해, 설계영역 매개변수화에 어려움이 있다. 등기하 해석법은 CAD 모델과 동일한 NURBS 기저 함수와 조정점을 해석에 이용함으로써 설계의 기하학적 변화를 해석모델에 직접적으로 표현할 수 있는 장점을 가진다. 하중조건이 설계 영역이 변화함에 따라 변하는 최적설계 문제의 경우, 정확한 설계 영역 표현은 법선 벡터, 즉 변화하는 하중의 방향과 곡률과 같은 고차항의 정보를 정확하게 표현할 수 있고, 따라서 목적함수를 최소 또는 최대화시키는 최적의 해로 이끌어 낸다. 유한요소법 또는 밀도법을 이용한 형상 최적설계에서 설계의존형 하중조건을 갖는 구조물의 문제를 푸는 경우, 최적설계가 진행됨에 있어 변화하는 경계의 부정확성 때문에 정확한 설계민감도를 얻기가 어려운 점이 있다. 본 논문에서는, 수치 예제를 통해 등기하 해석 기반의 형상 최적설계 방법론이 설계의존형 하중조건을 갖는 구조물 문제에서 수월성을 가짐을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.12
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• pp.1313-1323
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• 1991

n this thesis CAM(content Addressable Memory) generator and graphic display tool for run-plot sequence in automatic generation of CAM are presented. We show that implementing the layout generation, graphic menu, mouse driver, and data structure by using the basic classes is clear and easy in modification than the conventional procedural language. For the implementation of generator which is independent of design rule or process, we use the parameterized cell so that basic cell can be changed according to user's inputs. and perform the layout by means of placement and routing using pitch mathching. Finally, the display of CIF which generated and constitution of graphic menu for total run-plot sequence are explained.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.3
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• pp.278-285
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• 1999

This paper utilizes the method of Q-parameterization control to design a controller which solves the problem of imbalance in magnetic bearing systems. There are two methods to solve this problem using feedback controal. The first method is to compensate for the imbalance forces by generating opposing forces on the bearing surface (imbalance compensation). The second method is to make the rotor rotate around its axis of inertia (automatic balancing);in this case no imbalance forces will be generated. In this paper we deal with only imbalance compensation. The free parameter of the Q-parameterization controller is chosen such that these goals are achieved. After the introduction of a model of the magnetic bearing system, we explain the Q-parameterization controller design of the magnetic bearing system with emphasis on the rejection of sinusoidal disturbance for imbalance compensation design. The design objectives are formulated as a linear equations in the controller free paramete Q. Finally, simulation and experimental results are presented and showed the robustness and effectiveness of the proposed controllers.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.71-80
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• 2016

This study is based on the previous research which proved that "seeking convenience", "seeking low-cost" and "pleasures of shopping" are the major shopping motivation of online shopping. Research is conducted by using the trust as mediator, purchase intention as dependent variable. Also, differences between Chinese and Vietnamese consumers are applied in analysis of the model. The results were as follows: First, "seeking low-cost" and "pleasures of shopping" have positive effects on trust. Second, all shopping motivation have positive effect on purchase intention. Third, the trust has positive effect on purchase intention. Fourth, consumers' shopping motivation have significant difference in trust and purchase intention according to Chinese and Vietnamese consumers. The results of this study presented the strategic implications for operators at online shopping area.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.65-71
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• 2022

Recently, multi-material structural topology optimization is more critical because it provides reasonable solution to weight reduction challenges and can as well provide effective conceptual design. For conventional multi-material topology optimization (MMTO), the number of design variable increases when the number of candidate materials increases, and accordingly, a significant increase in computational time occurs. Therefore, MMTO with a single design variable, such as the phase section method (PSM) was proposed. This research is focused on improving the PSM, considering three major limitations: the composition ratio does not represent the area or volume ratio, design variables are not sufficiently concentrated to target values, and certain materials are created less than they are required. To address such limitations, the redefined composition ratio and adjusted parameters for better convergence are proposed. The validation of proposed modifications is verified via two- and three-dimensional numerical examples.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.672-676
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• 1999

Adsorption isotherm is the most fundamental information in adsorption separation-process. Directly from the elution profile of a peak, the elution-curve method and frontal analysis(FA) were utilized to measure the adsorption isotherm in this work. Using RP-HPLC, sample and the buffer added in mobile phase were 5'-GMP and sodium phosphate, respectively. In this experimental condition, the retention time was decreased with increase in the injected mass of sample. And the front part of a peak was very stiff, so Langmuir adsorption isotherm might be applied. By the elution-curve method, the parameters used in the isotherm were obtained by optimization method, while by the FA, the concentrations of stationary phase were measured from the elution curve and the isotherm was determined by regression analysis. Compared to FA, the consumption of sample was less, and only one or two injections were needed by the elution-curve method. Finally, the effect of concentration of sodium phosphate in mobile phase on the parameters of the isotherm was investigated.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.328-332
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• 2006

환경모델링 기법은 비선형 오염유출현상을 구조화하여 배출특성 규명 및 정책대안의 영향예측 도구로서 활용도가 증가하고 있다. 반면 복잡한 입력 파라미터의 구성은 모형운영에 있어 비정량적 수치를 적용할 수 있는 가능성을 내포하고 있다. 이러한 한계성을 극복하기 위해 최근 들어 GIS와 정보기술의 연계를 통한 자료관리 및 모형 매개변수 산출을 위한 연구들이 활발히 진행 중에 있다. GIS-모델링 분야의 기술적 성장에도 불구하고 정보구축의 시점, 주기, 구축 형태 등의 통일화가 이루어지지 않았다. 따라서 BASINS과 같은 기 구축된 정보 분석체계를 사용하고자 할 때 단위사업별로 구축된 공간정보의 구조해석을 다시 수행해야 하는 문제를 지니고 있다. 이는 구축된 정보를 사용하여 해석하고자 하는 주체가 분명하지 않고, 분석모델에서 요구하는 입력 자료의 구조를 명확하게 해석할 수 있는 정보기술과 분석기술의 연계부족으로 발생한 문제이다. 이에 본 연구의 목적은 NGIS사업을 통해 축척된 지형공간 데이터베이스와 GIS의 공간분석기능을 연계하여 유역 오염원 기상 공간정보의 관리, 유역 오염유출모형인 HSPF(Hydrologic Simulation Program-Fortran)의 운영정보 생성을 지원하는 지능형 정보관리시스템을 개발하는데 있다. 주 연구내용은 시스템 분석 및 설계, 기초 데이터 수집과 DB 구축, 지형 매개변수 산정을 위한 GIS-HSPF의 통합 인터페이스 구축이다. 개발된 KBASIN-HSPF는 EPA에 의해 개발된 BASIN의 유역분할, 하천망생성, 지형특성계수 산정 기능과 함께 우리나라의 지형.오염원.기상정보의 저장구조를 고려한 데이터 모델링, Tissen망에 준한 강우자료 생성 그리고 HSPF 모형운영정보 산정 및 전환기능을 포함하고 있다. KBASIN-HSPF는 유역기반 점.비점오염원 정보를 통합 관리하고자 하는 오염총량관리제의 기술적 정보관리 환경으로 활용가능하며, 기존의 오염유출모델링을 위해 자료준비부터 정보연계, 모형운영까지 분산된 환경에서 수행되었던 것을 통합환경하에서 진행함으로써 정보의 질적보장과 정보전환의 표준화방안을 제시하는 정보분석시스템이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2197-2202
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• 2011

In this study, we propose a new short dental implant and investigate its bio-mechanical characteristics by using three dimensional finite element analyses. The proposed dental implant has the central cavity which can be integrated with the core of cancellous bone remained by trepanning drill. We take the Bicon short implant as a reference model for studying the effects according to the shape of cavity. The parametric finite element model using ANSYS APDL has been built to determine which length, diameter and thread of central cavity would be effective to dissipate stress. The reduction of undesirable stress in adjacent bone which can suppress bone defects and the eventual failure of implants. The numerical results shows that the cavity of well-determined shape has the beneficial effects on reducing the bone absorption in cancellous bone.