• The KIPS Transactions:PartD
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• v.11D no.3
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• pp.671-682
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• 2004

As new and diverse information technologies are being introduced and software complexity is increased, software development cost and efforts are also sharply increased. Component-Based Development (CBD) technology is appealing as a new way to reduce the cost and effort by increasing reusability and maintainability. Component in CBD has variability infernally which enables customization of the component within the specific domain. A component user can easily set up internally variability parts though Required interface which is provided by the component. Enterprise JavaBeans (EJB) is utilized as a commercial standard to implement Java-based components. However, EJB constructs are limited in directly implementing Required interfaces of coarse-grained components［8］. In this paper, we define Required interface and propose interface-storage technique, class-storage technique, interface-generation technique, and Plug -in technique for implementing required interface of component. Interface-storage technique stores variable value in Required interface and class-storage technique take the Bean containg variability as Required interface without modification of component model. Interface-generation technique generates new Bean which takes the role of Required interface for component variability and Plug-in technique sets up component variability that component user plugged-in variable part externally The proposed four techniques conform to the semantics of CBD component interface and enable the implementation of high quality components.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.114-116
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• 2008

본 논문에서는 DC-DC 컨버터를 이용하여 조류 발전의 MPPT(Maximum Power Point Tracking) 제어를 제안하였다. 기존의 고정 듀티 제어를 이용한 발전 시스템과 가변 듀티를 이용한 발전시스템과의 비교를 통해서 가변듀티를 이용한 제어방법이 더욱 우수한 성능을 나타낸다는 것을 검증하였다. 제안한 시스템은 블레이드, 영구자석 동기전동기, 다이오드 정류기, DC-DC 컨버터로 구성되어 있으며, 고정듀티, 가변듀티 퍼지제어기를 이용한 가변듀티 방법을 이용하여 제어하였다. 본 시스템은 조류 속도의 측정 없이 컨버터의 듀티 가변으로 발전기가 최대 출력전력을 낼 수 있도록 제어하므로, 별도의 측정 장비가 필요 없다. 따라서 시스템 구성비용 적고, 복잡성이 낮으며, 효율이 높다. 알고리즘의 유효성은 Matlab Simulink를 통해서 검증하였다.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2007.11a
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• pp.202-205
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• 2007

With regal extension of balcony, the flexible design to remodel interior space of apartment has appeared as a new trend. But this desire of residents is allowed partially because of lack of flexible furniture design. So this study proposed to design for flexible livingroom cabinets at 30 pyong apartment according to life styles and furniture uses. To satisfy the storage and decoration of livingroom cabinets, it focuses on diverse decorative demands as well as practical functionality. And it suggests the applications of flexible factors; opening and closing, extension and reducing, assembling and dismantling, rotation and transfer according to 3 types like child-centered, hobby-centered, couple-centered family.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.365-372
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• 2000

현장상황에 대한 불충분한 자료와 파괴 메커니즘에 대한 불완전한 이해로 인해 발생하는 가변성(variability)과 불확실성(uncertainty)은 암반사면공학뿐만 아니라 지반공학에서 흔히 접하게 되는 문제점이다. 특히 암반사면공학에서는 이러한 가변성과 불확실성이 불연속면의 방향 및 기하학적 특성, 그리고 실내실험 결과의 분산으로 나타난다. 그러나 안전율(factor of safety)의 개념을 기초로 하는 전통적인 결정론적 해석방법(deterministic analysis)은 이러한 분산을 고려하지 않은 채 단일 대표 값만을 이용하여 구조물의 안정성을 판단하여 왔다. 확률론적 해석방법(probabilistic analysis)은 이러한 가변성과 불확실성을 효과적으로 정량화하여 해석에 이용할 수 있는 방법 중의 하나로 제안되었다. 이러한 해석방법은 불연속면의 기하학적 특성과 강도 특성을 확률변수(random variable)로 취급하여 신뢰성이론(reliability theory)과 확률이론(probability theory)을 근거로 분석하였으며 이를 기초로 하여 Monte Carlo Simulation과 같은 해석법을 이용, 구조물의 붕괴가능성을 확률로 표현하였다. 확률론적 해석 방법은 기존의 안전율을 대체하여 구조물의 안정성을 붕괴확률(probability of failure)로 제안하였으며 이 붕괴확률은 안전율의 확률분포함수 (probability density function)에서 안전율이 1보다 작을 가능성을 확률로 나타낸 수치이다. 본 논문에서는 확률론적 해석방법을 이용하여 불연속면 특성들의 확률특성을 고찰하였으며 이를 기초로 하여 암반사면의 안정성 해석에 응용했다.

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.81-88
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• 2008

This paper presents the travel demand estimation using interval estimation methods during the trip generation stage, and then followed the other three stages of the four stage trip estimation. We have used real data of Dae-jun City. To estimate travel demand using the interval estimation method, a reliability level was set to 95% by a upper bound value, a middle value and a lower bound value. The four stage traffic demand analysis procedure was equally applied and finally interval traffic was estimated. The result showed a difference between maximum values and middle values depending on the destination during the trip generation stage. It depends on an explanation ability of regression analysis. Most of interval estimation ratio resulted in the traffic assignment stage showed ${\pm}5{\sim}18%$ difference on the average and ${\pm}30{\sim}50%$ at the most.

• Journal of the Korean Chemical Society
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• v.67 no.1
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• pp.42-53
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• 2023

The purpose of this study is to obtain basic data for constructing a modeling practice program integrated with meta-modeling knowledge by analyzing the cognition level for each meta-modeling knowledge components through modeling practice in the context of the chemistry discipline content. A chemistry teacher conducted inquiry-based modeling practice including anomalous phenomena for 16 students in the second year of a science gifted school, and in order to analyze the cognition level for each of the three meta-modeling knowledge components such as model variability, model multiplicity, and modeling process, the inquiry notes recorded by the students and observation note recorded by the researcher were used for analysis. The recognition level was classified from 0 to 3 levels. As a result of the analysis, it was found that the cognition level of the modeling process was the highest and the cognition level of the multiplicity of the model was the lowest. The cause of the low recognitive level of model variability is closely related to students' perception of conceptual models as objective facts. The cause of the low cognitive level of model multiplicity has to do with the belief that there can only be one correct model for a given phenomenon. Students elaborated conceptual models using symbolic models such as chemical symbols, but lacked recognition of the importance of data interpretation affecting the entire modeling process. It is necessary to introduce preliminary activities that can explicitly guide the nature of the model, and guide the importance of data interpretation through specific examples. Training to consider and verify the acceptability of the proposed model from a different point of view than mine should be done through a modeling practice program.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.413-418
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• 2006

본 연구는 자갈하상을 갖는 하천에 대해 조도계수를 산정하고자 하상에 분포하는 입자에 작용하는 전단응력을 이용하여 등가조도를 산정하고 대상유량에 대해 수위를 산정할 수 있는 모형을 개발하였다. 개발된 모형의 적용성은 섬진강 하류부의 구례수위표와 송정수위표 구간에 대해 적용하였다. 그 결과 구례수위표지점에서 등가조도는 0.088m로 산정되었고, 이를 이용하여 Wark(1990)가 제시한 단위유량에 대한 연속방정식과 운동량방정식을 결합한 간단한 모형을 이용하여 각각의 대상유량에 대해 수위를 산정하였으며, 그 결과 6%이내의 오차를 보였다. 그리고 대상유량에 대해 계산된 수위를 이용한 부등류 해석을 실시하여 조도계수를 각각의 유량에 대해 산정하였다. 그 결과 관측된 수위와 계산된 수위에 의해 산정된 조도계수의 오차가 $0{\sim}0.002(6%)$의 오차를 보였고, 유량별로 조도계수를 산정할 수 있어 조도계수의 가변성도 고려할 수 있었다.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.45-51
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• 2009

A probabilistic approach may be adopted to predict freeze and thaw depths to account for the variability of (1) material properties, and (2) contemporary and future surface energy input parameters(e.g. air temperatures, cloud cover, snow cover) predicted with global climate models. To illustrate the probabilistic approach, an example of the predicted of thaw depths in cold regions is considered. More specifically, the Stefan equation is used together with the Monte Carlo simulation technique to make a probabilistic prediction of thaw penetration. The simulation results indicate that the variability in material properties, surface energy input parameters and temperature data can lead to significant uncertainty in predicting thaw penetration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.299-305
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• 2010

In general, the flexible forming die that has been used in the flexible forming process has the identical punch size; hence, its flexibility is relatively low because the range of allowable curvature radii is limited due to the uniform punch tip radius. Hence, a conceptual design of a sectional flexible die is presented for enhancing the flexibility of the forming process. Two punches of different sizes are used to configure the arbitrary forming surface. For a forming region with a relatively large curvature radius, a large punch array block is used; on the other hand, for the forming regions with small curvature radii, a small punch block is used. The cross-sectional profiles are compared with the target shape for evaluating the effectiveness of the process. Consequently, it is confirmed that the sectional flexible die can be used along with a combination of punch blocks of different sizes for manufacturing objective surfaces of complex shapes.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.12a
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• pp.747-757
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• 1999

본 논문에서는 가변구조제어기의 슬라이딩모드이득과 경계층두께(boundary layer thickness)를 신경망을 이용하여 계산하는 신경망 가변구조제어기를 제시한다. 제시된 방법은 신경망의 역전파오차 학습기능을 이용하여 슬라이딩모드이득과 경계층 범위를 계산할 수 있도록 신경망 제어기를 학습시킴으로써, 슬라이딩모드 제어법칙을 단순화 하고, 시스템 불확실성에 대하여 강인하며, 추적오차를 더욱 개선시킬 수 있다. 설계의 예와 시뮬레이션 결과를 통하여 제시된 방법에 대한 유용성을 보인다.