• 한국인터넷방송통신학회논문지
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• 제16권6호
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• pp.305-310
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• 2016

오늘날 데이터를 표현하고 교환하는 표준 언어로 XML을 사용하고 있다. XML의 개념적 모델을 정의하기 위해서는 XML이 가지는 다양한 요소들을 다이어그램으로 표현하는 표현 규칙과 생성된 다이어그램을 논리적 모델인 XML로 변환하는 변환 알고리즘을 정의해야 한다. 본 논문은 XML의 개념적 모델로부터 논리적 모델을 생성하기 위한 변환 기법을 제안한다. 본 논문에서 사용하는 개념적 모델로는 CMXML을 이용하고, 논리적 모델로 XML 스키마를 생성한다. 이를 위해 다이어그램으로 표현되는 CMXML을 정의하고, 이 다이어그램으로부터 XML 스키마를 생성하기 위한 자료구조를 정의하고 생성규칙을 정의하고, 변환 알고리즘을 제시한다.

• Wind and Structures
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• 제13권4호
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• pp.309-326
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• 2010

CFD techniques try to find their way in the bridge engineering realm nowadays. However, there are certain fields where they offer superior performance such as conceptual bridge design and bidding design. The CFD studies carried out for the conceptual design of a 425 m length cable-stayed bridge are presented. A CFD commercial package has been employed to obtain for a set of cross-sections the aerodynamic coefficients considering 2D steady state. Additionally, for those cross-sections which showed adequate force coefficients, unsteady 2D simulations were carried out to detect the risk of vortex shedding. Based upon these computations the effect on the aerodynamic behavior of the deck cross-section caused by a number of modifications has been evaluated. As a consequence, a new more feasible cross-section design has been proposed. Nevertheless, if the design process proceeds to a more detailed step a comprehensive set of studies, comprising extensive wind tunnel tests, are required to better find out the aerodynamic bridge behavior.

• 한국인터넷방송통신학회논문지
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• 제17권6호
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• pp.211-216
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• 2017

XML은 데이터의 표현 및 교환의 사실상 표준으로 자리 잡고 있으며, XML 자체가 데이터를 저장, 관리하기 위한 구조로 되어있지만, 다양하고 복잡한 표현으로 인해 문서 구조를 한 눈에 파악하기에는 어려운 점이 있어 개념적 모델의 도구로 사용하기 적절하지 못한 점이 있다. 본 논문은 XML 스키마 문서 구조를 보다 쉽게 이해할 수 있도록 개념적 모델로 변환하는 기법을 제안한다. 이를 위해 개념적 모델 도구로 사용한 CMXML을 기술하고, XML 스키마 구조를 CMXML 다이어그램으로 변환하기 위한 변환 규칙과 자료구조를 제시한다. 변환절차는 XML 스키마 문서를 입력받아 본 연구에서 제안하는 변환기법을 적용하여 CMXML 다이어그램을 생성한다.

• Steel and Composite Structures
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• 제23권2호
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• pp.173-186
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• 2017

Conceptual configuration and seismic performance of high-rise steel frame-brace structure are studied. First, the topology optimization problem of minimum volume based on truss-like material model under earthquake action is presented, which is solved by full-stress method. Further, conceptual configurations of 20-storey and 40-storey steel frame-brace structure are formed. Next, the 40-storeystructure model is developed in Opensees. Two common configurations are utilized for comparison. Last, seismic performance of 40-storey structure is derived using nonlinear static analysis and nonlinear dynamic analysis. Results indicate that structural lateral stiffness and maximum roof displacement can be improved using brace. Meanwhile seismic damage can also be decreased. Moreover, frame-brace structure using topology optimization is most favorable to enhance lateral stiffness and mitigate seismic damage. Thus, topology optimization is an available way to form initial conceptual configuration in high-rise steel frame-brace structure.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.937-942
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• 2005

It is necessary to estimate the runoff hydrograph and peak flood discharge using law of probability for synthetic flood control policy and design of hydraulic structures. Rainfall analysis is needed in the process of peak flood discharge estimation and the time distribution of a design rainfall is a very important process in the analysis. In this study, we estimate design flood for a small urban basin and a rural basin of medium scale which have different travel times. The Huff method is widely used in Korea for the time distribution of design rainfall to estimate design flood. So, we use Huff method and a conceptual method which is suggested in this study for the comparative purpose. The 100-year frequency rainfall is used to estimate design flood for each basin and the design flood is compared with the existing design flood. As the result, the design flood is overestimated $14.6m^3/sec$ by Huff method and is underestimated $70.9m^3/sec$ by a conceptual method for the rural basin. For the small urban basin, the design flood is excessively overestimated $294.65m^3/sec$ by Huff method and is overestimated $173m^3/sec$ by a conceptual method. The reason of excessive overestimation by Huff method in the small urban basin is that the increased rate of rainfall intensity according to the decrease of duration is large and the duration exceeds the time of concentration when the increased rainfall intensity is concentrated in a quartile. Therefore, we suggested a conceptual method for the time distribution of design rainfall by considering the rainless period and duration. Especially, the conceptual method might be useful for the small urban basin with short concentration time which the design flood is overestimated by Huff method.

• 한국철도학회논문집
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• 제11권3호
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• pp.300-310
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• 2008

본 논문에서는 국내철도차량안전기준의 충돌안전 요구사항을 만족하는 동력 분산형 고속전철의 충돌안전도 개념설계에 대하여 연구하였다. 국내안전기준에는 36km/h 열차 대 열차 충돌, 15ton 변형체 장애물과 110km/h 충돌 등 2가지 중충돌 사고에 대한 충돌안전성능을 요구한다. 한국형 분산형 차세대고속열차는 17ton 축중의 동력집중형 KTX와 달리 13ton 축중을 가지는 2TC-6M로 구성된다. 이론적 수치적 해석을 통하여 주요 압괴구조 및 부품의 평균압괴하중과 변형량을 에너지 흡수 관점에서 충돌안전도 개념설계안으로 도출하였다. 도출된 개념 설계안은 1차원 막대-스프링-댐퍼-질량 동역학 시뮬레이션 결과로부터 국내 충돌안전기준을 잘 만족시킬 수 있음을 보였다.

• International Journal of Computer Science & Network Security
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• 제21권5호
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• pp.139-150
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• 2021

Object orientation has become the predominant paradigm for conceptual modeling (e.g., UML), where the notions of class and object form the primitive building blocks of thought. Classes act as templates for objects that have attributes and methods (actions). The modeled systems are not even necessarily software systems: They can be human and artificial systems of many different kinds (e.g., teaching and learning systems). The UML class diagram is described as a central component of model-driven software development. It is the most common diagram in object-oriented models and used to model the static design view of a system. Objects both carry data and execute actions. According to some authorities in modeling, a certain degree of difficulty exists in understanding the semantics of these notions in UML class diagrams. Some researchers claim class diagrams have limited use for conceptual analysis and that they are best used for logical design. Performing conceptual analysis should not concern the ways facts are grouped into structures. Whether a fact will end up in the design as an attribute is not a conceptual issue. UML leads to drilling down into physical design details (e.g., private/public attributes, encapsulated operations, and navigating direction of an association). This paper is a venture to further the understanding of object-orientated concepts as exemplified in UML with the aim of developing a broad comprehension of conceptual modeling fundamentals. Thinging machine (TM) modeling is a new modeling language employed in such an undertaking. TM modeling interlaces structure (components) and actionality where actions infiltrate the attributes as much as the classes. Although space limitations affect some aspects of the class diagram, the concluding assessment of this study reveals the class description is a kind of shorthand for a richer sematic TM construct.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.229-236
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• 1998

Port structures are one of the important infrastructure of the nation. To ensure safety and extend lifetime of the existing port structures, it is necessary to develop proper maintenance program. In this study, port inspection manual for pier type structure are developed. The flow of inspection program is designed and defect type for each component of wharf is classified. Also systematic method of rating and evaluation is developed together with conceptual design of port maintenance data base system.

• 대한건축학회논문집:구조계
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• 제35권4호
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• pp.167-174
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• 2019

Cable-stayed structures provide a lot of possibilities toward the development of innovative structural forms regarding their expressiveness and uniqueness. Such cable-stayed structures, as form-active structures, can obtain a family of alternatives by changing parameters for defining geometric shapes. The concept of graphic statics is utilized to explain the relationship between the load path and structural forms because the load path of cable structures has something to do with their structural geometry. Moreover, this structural geometry has a dominant effect on both structural efficiency and structural elegancy. The proposed design method in this study will help designers conceive innovative structural forms considering structural safety, material efficiency, and structural art altogether.

• Structural Engineering and Mechanics
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• 제48권5호
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• pp.615-642
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• 2013

In this paper a study on prestressed concrete slab bridges is presented. A design philosophy based on the concept of load balancing through prestressing is proposed in order to minimize the effects of delayed deformations due to creep. Aspects related to the stress redistribution inside these bridges for time-dependent phenomena are analyzed and discussed, by applying the principles of aging linear visco-elasticity. Prestressing is seen as an equivalent external load which counterbalances the permanent loads applied to the bridge, nullifying the elastic deflections due to sustained loads, and thus avoiding the related delayed deformations. An optimization of the structural behavior through the use of one-way prestressing is achieved. The determination of a convenient variable depth of slab bridges and the correspondent layout of tendons is considered as a useful means for applying the load balancing concept in actual cases of structures like long cantilevers or bridge decks. A case-study related to the slab bridges built 30 years ago at Jeddah in Saudi Arabia is presented and discussed, in order to show the effectiveness of the proposed approach to the conceptual design of prestressed concrete bridges.