• Title/Summary/Keyword: Modeling process

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Simulation and Control of the Molten Carbonate System using Aspen $Dynamics^{TM}$ and ACM (Aspen $Dynamics^{TM}$와 ACM을 이용한 용융탄산염 연료전지 시스템의 모사 및 제어)

  • Jeon, Kyoung Yein;Kwak, Ha Yeon;Kyung, Ji Hyun;Yoo, Ahrim;Lee, Tae Won;Lee, Gi Pung;Moon, Kil Ho;Yang, Dae Ryook
    • Korean Chemical Engineering Research
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    • v.49 no.4
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    • pp.423-431
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    • 2011
  • Recentincreasing awareness of the environmental damage caused by the $CO_2$ emission of fossil fuelsstimulated the interest in alternative and renewable sources of energy. Fuel cell is a representative example of hydrogen energy utilization. In this study, Molten Carbonate Fuel Cell system is simulated by using $Aspen^{TM}$. Stack model is consisted of equilibrium reaction equations using $ACM^{TM}$(Aspen Custom Modeler). Balance of process of fuel cell system is developed in Aspen $Plus^{TM}$ and simulated at steady-state. Analysis of performance of the system is carried out by using sensitivity analysis tool with main operating parameters such as current density, S/C ratio, and fuel utilization and recycle ratio.In Aspen $Dynamics^{TM}$, dynamics of MCFC system is simulated with PID control loops. From the simulation, we proposed operation range which generated maximum power and efficiency in MCFC power plant.

A Study of the Establishment of Small and Medium Sized Architectural Design Firm BIM Environment based on Virtual Desktop Infrastructure (가상 데스크톱 인프라(VDI) 기술을 활용한 중소규모 설계사의 BIM 사용자 별 데스크탑 자원 할당 전략에 관한 연구)

  • Lee, Kyuhyup;Shin, Joonghwan;Kwon, Soonwook;Park, Jaewoo
    • Korean Journal of Construction Engineering and Management
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    • v.17 no.5
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    • pp.78-88
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    • 2016
  • Recently BIM technology has been expanded for using in construction project. However its spread has been delayed than the initial expectations, due to the high-cost of BIM infrastructure development, the lack of regulations, the lack of process and so forth. In design phase, especially, collaboration based on BIM system has being a key factor for successful next generation building project. Through the analysis of current research trend about IT technologies, virtualization and BIM service, data exchange such as drawing, 3D model, object data, properties using cloud computing and virtual server system is defined as a most successful solution. In various industrial fields, cloud computing technology is utilized as a promising solution which can reduce time and cost of hardware infrastructure. Among the cloud computing technology, VDI is receiving a great deal of attention from it market as an essential part cloud computing. VDI enables to host multiple individual virtual machines by using hypervisor. It has an advantage to easy main device management. Therefore, this study implements a step-by-step user's DaaS by analyzing the desktop resource data of the workers from Pre-design phase to Schematic design, Design develop and Construction design phase. It also develops BIM environment based on test of BIM modeler and designers in architectural design firm. The goal of the study is to enable the cloud computing BIM server. It provides cost saving, high-performance quality of working environment and cooperation's convenience and high security when doing BIM work in small and medium sized architectural design firm.

Numerical Modeling for the Detection of Debris Flow Using Detailed Soil Map and GIS (정밀토양도와 GIS를 이용한 토석류 발생지역 예측 분석)

  • Kim, Pan Gu;Han, Kun Yeun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.1
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    • pp.43-59
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    • 2017
  • This study presents the prediction methodology of debris flow occurrence areas using the SINMAP model. Former studies used a single calibration region applying some of the soil test results to predict debris flow occurrence in SINMAP model, which couldn't subdivide the soil properties for the target areas. On the other hands, a multi-calibration region using a detailed soil map and soil strength parameters (c, ${\phi}$) for each soil series to make up for limitation of former studies is proposed. In this process, soils with soil erodibility factor (K) are classified into three types: 1) gravel and gravelly soil. 2) sand and sandy soil, and 3) silt and clay. In addition, T/R estimation method using mean elevation of target area instead of T/R method using actual occurrence time is suggested in this study. The suggested method is applied to Seobyeok-1 ri area, Bonghwa-gun where debris flow occurred. As a result of comparison between two T/R estimation method, both T/R estimations are almost equal. Therefore, the suggested methodologies in this study will contribute to set up the national-wide mitigation plan against debris flow occurrence.

Prediction of Preliminary Pogo Instability on a Space Launch Vehicle (예비설계 단계 우주발사체의 공급/추진계 모델을 이용한 포고 불안정성 예측)

  • Lee, SangGu;Sim, JiSoo;Shin, SangJoon;Seo, Yongjun;Ann, Sungjun;Song, Huiseong;Kim, Youdan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.21 no.6
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    • pp.64-72
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    • 2017
  • The longitudinal dynamic instability which can occur in the fueling process of a space launch vehicle is called pogo. It is caused by coupling between the fuselage and propulsion system and they would be formed as a closed-loop system. so that the amplitude of the response may increase or decrease. In this paper, a mathematical model which is applicable to the systematic pogo analysis of a general launch vehicle is developed for an example of space shuttle. The formulations are composed of the linearized second-order differential equation for the propulsion system, and of the pressure, weight displacement, and generalized displacement. Those are important parameters for pogo analysis, are derived through eigenvalue analysis. By the formulation suggested in this paper, it is expected that mathematical modeling method of the pogo system can be obtained and systematic pogo stability analysis for any launch vehicle will be enabled.

A Study on the Effective Method to Producing Data for The ROKA Live Fire Training Range Safety (한국군 실 사격 훈련간 효율적인 안전지대 데이터 구축 방안 연구)

  • Lee, June-Sik;Choi, Bong-Wan;Oh, Hyun-Seung
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.38 no.3
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    • pp.64-77
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    • 2015
  • An effective method for produce munitions effectiveness data is to calculate weapon effectiveness indices in the US military's Joint Munitions Effectiveness Manuals (JMEM) and take advantage of the damage evaluation model (GFSM) and weapon Effectiveness Evaluation Model (Matrix Evaluator). However, a study about the Range Safety that can be applied in the live firing exercises is very insufficient in the case of ROK military. The Range Safety program is an element of the US Army Safety Program, and is the program responsible for developing policies and guidance to ensure the safe operation of live-fire ranges. The methodology of Weapon Danger Zone (WDZ) program is based on a combination of weapon modeling/simulation data and actual impact data. Also, each WDZ incorporates a probability distribution function which provides the information necessary to perform a quantitative risk assessment to evaluate the relative risk of an identified profile. A study of method to establish for K-Range Safety data is to develop manuals (pamphlet) will be a standard to ensure the effective and safe fire training at the ROK military education and training and environmental conditions. For example, WDZs are generated with the WDZ tool as part of the RMTK (Range Managers Tool Kit) package. The WDZ tool is a Geographic Information System-based application that is available to operational planners and range safety manager of Army and Marine Corps in both desktop and web-based versions. K-Range Safety Program based on US data is reflected in the Korean terrain by operating environments and training doctrine etc, and the range safety data are made. Thus, verification process on modified variables data is required. K-Range Safety rather than being produced by a single program, is an package safety activities and measures through weapon danger zone tool, SRP (The Sustainable Range Program), manuals, doctrine, terrain, climate, military defence M&S, weapon system development/operational test evaluation and analysis to continuously improving range safety zone. Distribution of this K-range safety pamphlet is available to Army users in electronic media only and is intended for the standing army and army reserve. Also publication and distribution to authorized users for marine corps commands are indicated in the table of allowances for publications. Therefore, this study proposes an efficient K-Range Safety Manual producing to calculate the danger zones that can be applied to the ROK military's live fire training by introducing of US Army weapons danger zone program and Range Safety Manual

Study on a Demand Volume Estimation Method using Population Weighted Centroids in Facility Location Problems (시설물 입지에 있어 인구 중심점 개념을 이용한 수요 규모 추정 방법 연구)

  • Joo, Sung-A;Kim, Young-Hoon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.10 no.2
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    • pp.11-22
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    • 2007
  • This paper is to discuss analytical techniques to estimate demand sizes and volumes that determine optimal locations for multiple facilities for a given services. While demand size estimation is a core part of location modeling to enhance solution quality and practical applicability, the estimation method has been used in limited and restrict parts such as a single population centroid in a given larger census boundary area or small theoretical application experiments(e.s. census track and enumeration district). Therefore, this paper strives to develop an analytical estimation method of demand size that converts area based demand data to point based population weighted centroids. This method is free to spatial boundary units and more robust to estimate accurate demand volumes regardless of geographic boundaries. To improve the estimation accuracy, this paper uses house weighted value to the population centroid calculation process. Then the population weighted centroids are converted to individual demand points on a grid formated surface area. In turn, the population weighted centroids, demand points and network distance measures are operated into location-allocation models to examine their roles to enhance solution quality and applicability of GIS location models. Finally, this paper demonstrates the robustness of the weighted estimation method with the application of location-allocation models.

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An Object-Oriented Analysis and Design Methodology for Secure Database Design -focused on Role Based Access Control- (안전한 데이터베이스 설계를 위한 객체지향 분석·설계 방법론 -역할기반 접근제어를 중심으로-)

  • Joo, Kyung-Soo;Woo, Jung-Woong
    • Journal of the Korea Society of Computer and Information
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    • v.18 no.6
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    • pp.63-70
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    • 2013
  • In accordance with the advancement of IT, application systems with various and complex functions are being required. Such application systems are typically built based on database in order to manage data efficiently. But most object-oriented analysis design methodologies for developing web application systems have not been providing interconnections with the database. Since the requirements regarding the security issues increased, the importance of security has become emphasized. However, since the security is usually considered at the last step of development, it is difficult to apply the security during the whole process of system development, from the requirement analysis to implementation. Therefore, this paper suggests an object-oriented analysis and design methodology for secure database design from the requirement analysis to implementation. This object-oriented analysis and design methodology for secure database design offers correlations with database that most existing object-oriented analysis and design methodologies could not provide. It also uses UMLsec, the modeling language, to apply security into database design. In addition, in order to implement security, RBAC (Role Based Access Control) of relational database is used.

Development of 3-Dimensional Rebar Detail Design and Placing Drawing System (3차원 배근설계 및 배근시공도 작성 자동화 시스템 개발)

  • Choi, Hyun-Chul;Lee, Yunjae;Lee, Si Eun;Kim, Chee Kyeong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.4
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    • pp.289-296
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    • 2014
  • The rebar detailing is an important work influencing the final performance and quality of RC structures. But it is one of the most irrational and illogical activity in construction site. Many groups of workers, including main contractors, structural engineers, shop drawers, rebar fabricators, and etc., participate in this activity. A loosely-organized process for this activity is apt to produce a big amount of rebar loss or even degraded structures. A 3-dimensional rebar auto-placing system, called as Rebar Hub, has been designed and implemented in this research. Rebar Hub provides a totally integrated service from 3D structural modeling of buildings to rebar auto-placing considering anchorage, splice, and the length of ordered rebar. In addition, Rebar Hub can recognize the 2D drawing CAD files and then build 3D structural models which are used for the start point of 3D rebar auto-placing. After rebar auto-placing, each members of the 3D structural model have rebar information belonging to them. It means that the rebar information can be used for the afterward works such as quantity-survey, manufacturing and fabrication of rebars. Rebar Hub is showing outstanding performance while applying to practical projects. It has almost five times productivity and reduces the rebar loss up to 3~8% of the initially-surveyed amount of rebar.

Structural Design and Analysis of a Hydraulic Coiling Arm for Offshore Wind-turbine Submarine Cable (해상풍력 해저케이블 하역용 유압식 코일링 암 구조설계 및 해석)

  • Kim, Myung-Hwan;Kim, Dong-Hyun;Oh, Min-Woo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.1
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    • pp.1-7
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    • 2013
  • Structural design and analysis of a coiling arm unloading machine for submarine cable have been originally conducted in this study. Three-dimensional CAD modeling process is practically applied for the structural design in detail. Finite element method(FEM) and multi-body dynamics(MBD) analyses are also used to verify the safety and required motions of the designed coiling arm structure. The effective moving functions of the designed coiling arm with respect to rotational and radial motions are achieved by adopting bearing-roller mechanical parts and hydraulic system. Critical design loading conditions due to its self weight, carrying cables, offshore wind, and hydraulic system over operation conditions are considered for the present structural analyses. In addition, possible inclined ground conditions for the installation of the designed coiling arm are also considered to verify overturn stability. The present hydraulic type coiling arm system is originally designed and developed in this study. The developed coiling arm has been installed at a harbor, successfully tested its operational functions, and finished practical unloading mission of the submarine cable.

Coupled Analysis with Digimat for Realizing the Mechanical Behavior of Glass Fiber Reinforced Plastics (유리섬유 강화 플라스틱의 역학적 거동 구현을 위한 Digimat와의 연성해석 연구)

  • Kim, Young-Man;Kim, Yong-Hwan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.6
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    • pp.349-357
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    • 2019
  • Finite element method (FEM) is utilized in the development of products to realistically analyze and predict the mechanical behavior of materials in various fields. However, the approach based on the numerical analysis of glass fiber reinforced plastic (GFRP) composites, for which the fiber orientation and strain rate affect the mechanical properties, has proven to be challenging. The purpose of this study is to define and evaluate the mechanical properties of glass fiber reinforced plastic composites using the numerical analysis models of Digimat, a linear, nonlinear multi-scale modeling program for various composite materials such as polymers, rubber, metal, etc. In addition, the aim is to predict the behavior of realistic polymeric composites. In this regard, the tensile properties according to the fiber orientation and strain rate of polybutylene terephthalate (PBT) with short fiber weight fractions of 30wt% among various polymers were investigated using references. Information on the fiber orientation was calculated based on injection analysis using Moldflow software, and was utilized in the finite element model for tensile specimens via a mapping process. LS-Dyna, an explicit commercial finite element code, was used for coupled analysis using Digimat to study the tensile properties of composites according to the fiber orientation and strain rate of glass fibers. In addition, the drawbacks and advantages of LS-DYNA's various anisotropic material models were compared and evaluated for the analysis of glass fiber reinforced plastic composites.