• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1000-1007
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• 2007

Recently, many critical control systems are developed using formal methods. When software applied to such systems is developed, the employment of formal methods in the software requirements specification and verification will provide increased assurance for such applications. Earlier error of overlooked requirement specification can be detected using formal specification method. Also the testing and full verification to examine all reachable states using model checking to undertake formal verification are able to be completed. In the comparison of other formal specification methods, we choose the Z formal language for applying to the train control system. Using Z is able to realize higher correctness in the requirement specification, and we propose the Statemate of the best solution in formal verification tools for the system modeling and verification. The Statemate makes it possible to prove thoroughly the system execution from the simple graphical modeling of the complicated train control system. Then we can expect that the model-based formal method combining Z with Statemate will be utilized widely for the railway systems due to various strong points.

• 한국CDE학회논문집
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• 제14권4호
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• pp.225-233
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• 2009

The objective of this paper is to examine a construction method and verify PLC logic using the logical modeling and simulation of a virtual plant has complex manufacturing system and the domain of application is car body assembly line of automotive industrial operated by PLC Program. The proposed virtual plant model for the analysis of the construction method consists of three types of components which are virtual device, intermediary transfer and controller is modeled by logical model but it the case of the verification of PLC program, HMI and PLC logic in the field substitute for the controller. The implementation of the proposed virtual plant model is conducted PLC Studio which is an object-oriented modeling language based on logical model. As a result, proposed methods enable 3D graphics is designed in the analysis step to use for verification of PLC program without special efforts.

• 대기
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• 제21권2호
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• pp.197-208
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• 2011

The objective of this study is to describe the short-range forecast system of the Korea Air Force (KAF) and to verificate its performace in 2009 summer. The KAF weather prediction model system, based on the Weather Research and Forecasting (WRF) model (i.e., the KAF-WRF), is configured with a parent domain overs East Asia and two nested domains with the finest horizontal grid size of 2 km. Each domain covers the Korean peninsula and South Korea, respectively. The model is integrated for 84 hour 4 times a day with the initial and boundary conditions from National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) data. A quantitative verification system is constructed for the East Asia and Korean peninsula domains. Verification variables for the East Asia domain are 500 hPa temperature, wind and geopotential height fields, and the skill score is calculated using the difference between the analysis data from the NCEP GFS model and the forecast data of the KAF-WRF model results. Accuracy of precipitation for the Korean penisula domain is examined using the contingency table that is made of the KAF-WRF model results and the KMA (Korea Meteorological Administraion) AWS (Automatic Weather Station) data. Using the verification system, the operational model and parallel model with updated version of the WRF model and improved physics process are quantitatively evaluated for the 2009 summer. Over the East Aisa region, the parallel experimental model shows the better performance than the operation model. Errors of the experimental model in 500 hPa geopotential height near the Tibetan plateau are smaller than errors in the operational model. Over the Korean peninsula, verification of precipitation prediction skills shows that the performance of the operational model is better than that of the experimental one in simulating light precipitation. However, performance of experimental one is generally better than that of operational one, in prediction.

• 한국시뮬레이션학회논문지
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• 제28권1호
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• pp.41-47
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• 2019

국방 시뮬레이션은 여러 무기체계를 실험하고 그 효용성을 평가하기 위해 활발히 사용된다. AddSIM 환경의 경우 국방 시뮬레이션에서 다루는 무기체계들을 보다 통합적인 관점에서 지원하기 위해 고안된 시뮬레이션 프레임워크로 재사용성과 확장성을 고려하여 설계되었다. AddSIM에서 사용되는 모델의 경우 기본 모델 구조에 대한 정보와 실제 무기 체계의 설계를 위해 사용되는 사용자 코드 영역에서의 검증이 통합적이며 정확한 시뮬레이션을 위해 필요하다. 따라서 본 논문에서는 AddSIM에서 사용되는 모델들에 대한 완전성을 위해 사용된 동적 검증 방법에 대해 설명한다. 사용자 코드 동적 검증 방법에 대해서는 명세 기법과 검증을 위한 알고리즘에 대해 설명한다. 또한, 검증 명세 기법 및 알고리즘을 바탕으로 구현된 동적 검증기 프로토타입에 대해 소개하며, 사례 연구에서는 AddSIM 환경에서 구현된 시뮬레이션 예제를 바탕으로 수행한 검증 결과를 분석한다.

• 융합신호처리학회논문지
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• 제12권4호
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• pp.309-314
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• 2011

시스템의 복잡도가 증가함에 따라 상위수준 추상화에 기반한 시스템수준 설계 및 하드웨어의 기능적 검증을 위한 방법론의 중요성이 부각되고 있으며, Verilog HDL(Hardware Description Language)에 하드웨어 검증기능이 추가된 SystemVerilog를 이용하는 시스템수준의 기능적 검증방법이 각광받고 있다. SystemVerilog는 Verilog HDL의 확장된 형태로 하드웨어 설계언어와 검증언어의 특징을 모두 포함하나, 다중상속을 허용하지 않는다. 본 논문에서는 SystemVerilog 기반의 검증환경과 다중상속을 허용하는 SystemC 의 구성요소를 SystemVerilog DPI(Direct Programming Interface) 및 ModelSim macro를 이용해 결합한 다중상속이 가능한 검증환경을 구성한다. 다중상속이 허용된 검증환경 시스템은 특정부분을 수정 후 재실행으로 DUT(Design Under Test)의 기능 검증을 쉽게 수행할 수 있으며, OOP(Object Oriented programming) 기법을 이용한 코드의 재사용성이 높아 또 다른 DUT의 동작 검증에 재사용할 수 있다.

• Coupled systems mechanics
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• 제4권1호
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• pp.67-98
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• 2015

Numerical prediction of dynamic behavior of fully coupled saturated porous media is of great importance in many engineering problems. Specifically, static and dynamic response of soils - porous media with pores filled with fluid, such as air, water, etc. - can only be modeled properly using fully coupled approaches. Modeling and simulation of static and dynamic behavior of soils require significant Verification and Validation (V&V) procedures in order to build credibility and increase confidence in numerical results. By definition, Verification is essentially a mathematics issue and it provides evidence that the model is solved correctly, while Validation, being a physics issue, provides evidence that the right model is solved. This paper focuses on Verification procedure for fully coupled modeling and simulation of porous media. Therefore, a complete Solution Verification suite has been developed consisting of analytical solutions for both static and dynamic problems of porous media, in time domain. Verification for fully coupled modeling and simulation of porous media has been performed through comparison of the numerical solutions with the analytical ones. Modeling and simulation is based on the so called, u-p-U formulation. Of particular interest are numerical dispersion effects which determine the level of numerical accuracy. These effects are investigated in detail, in an effort to suggest a compromise between numerical error and computational cost.

• 토지주택연구
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• 제11권3호
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• pp.93-101
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• 2020

Recently, as a BIM-based construction simulation system, 4D CAD tools using virtual reality (VR) objects are being applied in construction project. In such a system, since the expression of the object is based on VR image, it has a sense of separation from the real environment, thus limiting the use of field engineers. For this reason, there are increasing cases of applying augmented reality (AR) technology to reduce the sense of separation from the field and express realistic VR objects. This study attempts to develop a methodology and BIM module for the pre-construction verification system using AR technology to increase the practical utility of VR-based BIM objects. To this end, authors develop an AR-based drawing verification function and drawing object-based 4D model augmentation function that can increase the practical utility of 2D drawings, and verify the applicability of the system by performing case analysis. Since VR object-based image has a problem of low realism to field engineers, the linking technology between AR object and 4D model is expected to contribute to the expansion of the use of 4D CADsystem in the construction project.

• Computers and Concrete
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• 제8권2호
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• pp.177-192
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• 2011

This research paper aims at computer based modeling of carbonation induced corrosion under extreme conditions and its experimental verification by incorporating enhanced electrochemical and mass balance equations based on thermo-hygro physics with strong coupling of mass transport and equilibrium in micro-pore structure of carbonated concrete for which the previous research data is limited. In this paper the carbonation induced electrochemical corrosion model is developed and coupled with carbon dioxide transport computational model by the use of a concrete durability computer based model DuCOM developed by our research group at concrete laboratory in the University of Tokyo and its reliability is checked in the light of experiment results of carbonation induced corrosion mass loss obtained in this research. The comparison of model analysis and experiment results shows a fair agreement. The carbonation induced corrosion model computation reasonably predicts the quantitative behavior of corrosion rate for normal air dry relative humidity conditions. The computational model developed also shows fair qualitative corrosion rate simulation and analysis for various pH levels and coupled environmental actions of chloride and carbonation. Detailed verification of the model for the quantitative carbonation induced corrosion rate computation under varying relative conditions, different pH levels and combined effects of carbonation and chloride attack remain as scope for future research.

• 한국정밀공학회지
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• 제22권4호
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• pp.68-75
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• 2005

This paper presents a new method for the optimization of feed rate in sculptured surface machining. A NC verification model based on Z-map was utilized to obtain chip load according to feed per tooth. This optimization method can regenerate a new NC program with respect to the commanded cutting conditions and the NC program that was generated from CAM system. The regenerated NC program has not only the same data of the ex-NC program but also the updated feed rate in every block. The new NC data can reduce the cutting time and produce precision products with almost even chip load to the feed per tooth. This method can also reduce tool chipping and make constant tool wear.

• 한국생산제조학회지
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• 제6권1호
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• pp.51-58
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• 1997

The verification of the STL file is essential to build the confident parts using a RP machine, because the STL file obtained from the CAD software has many errors-the orientation of triangle does not coincide with adjacent triangles or some triangles are omitted, overlpped and so forth. Especially, the STL file translated from the surface model has more errors than those translated from the solid model. In this study, all possible errors were classified with the most general from and the causes of errors were analyzed to verify and correct errors. Using the triangle based non-manifold geometric modeling, these errors were corrected. Especially, this study took the notice of the problem about the intersected triangles and non-manifold properties overlooked in the previous studies. But this study has a penalty on computing time of $O(n^2)$.