• Title/Summary/Keyword: 2-phase model

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Development of Regional Problem Solving Entrepreneurship Education Program: Based on Competency-Based Curriculum Design (지역사회 문제해결형 기업가정신 교육과정 개발: 역량 기반 교육과정 설계를 기반으로)

  • Choi, Yong Seok;Part, Jong Seok;Baek, Bo Hyun
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.5
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    • pp.187-203
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    • 2022
  • As the economic, social, and environmental problems of the local community reach a serious level, our society is realizing the need to foster young talents who discover opportunities in local issues through entrepreneurship education and create social values through creative challenges. However, entrepreneurship education programs are generally focused on commerciality, so customized education programs to solve regional problems are insufficient. Therefore, this study aimed to develop a community problem-solving entrepreneurship curriculum. In this study, a competency based curriculum model was applied to develop the curriculum, and regional problem-solving entrepreneurship competencies were derived through expert advice from a total of 10 people. In the process, the Delphi methodology was additionally used to reduce the possibility of errors in the competency model. As a result of the study, a total of 23 regional problem-solving entrepreneurship competencies were confirmed, and knowledge(K) - skill(S) - attitude(A) by competency consisted of 5, 9, and 9, respectively. By applying this to Dunham's problem-solving six-step model, modular learning support measures were developed in the order of phase 1(problem discovery), phase 2(problem analysis), phase 3(plan), phase 4(measure), and phase 5(evaluation). This study is meaningful in that it integrated theory and practice by developing specific entrepreneurship curriculum and learning support measures based on the theoretical model devised in social welfare. In addition, it has implications in that it developed a regional problem-solving entrepreneurship competency model based on expert advice and proposed a specific curriculum based on this.

Designing Processes for Ubiquitous-based Sport Business Model (유비쿼터스 기반 스포츠비즈니스모델 설계과정)

  • In, Sang-Woo
    • Journal of Information Technology Services
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    • v.10 no.4
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    • pp.47-65
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    • 2011
  • Business organizations are asked to create new business models utilizing current technological innovations such as ubiquitous computing technology for developing new domains of business to obtain a competitive advantage and achieve a sustainable development. This study was focused on the processes for developing new and practical business models. The purpose of this study was to propose ubiquitous sport business modeling processes from the modeling framework. In particular, this study focused on developing new, pragmatic, and effective sport business models, and this new type of business is defined as 'u-sport.' For design the business model, extensive literature reviews and case studies were conducted for benchmarking the cases and expert group review was conducted for developing u-sport business model framework. The suggested business modeling processes in this study were consisted of four phases; 1) organization strategy level setting phase, 2) business strategy level setting phase, 3) business structure level setting phase, and 4) service level setting phase. The modeling processes were verified to adapt ubiquitous sport business. This designing and modeling process is expected to play a significant role on enhancing the technology-based business environments as the process mainly focuses on the service and consumer oriented approach rather than technology and suppliers oriented approach. In conclusion, establishing sport business models by adapting the service modeling process will deliver an exponential growth and development of future ubiquitous based industry.

Electron Diffraction of Icosahedral Twin (정 20면체 쌍정의 전자회절)

  • 김호성;정수진
    • Korean Journal of Crystallography
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    • v.1 no.2
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    • pp.91-98
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    • 1990
  • A twin model for icosahedral phase of rapidly solidified AB transition metal alloy is suggested. Electron diffraction patterns of our icosahedral twin model are simulated, taking into account of multiple diffraction. The simulated pattern with 5-fold symmetry well agrees with the experimental one. Our twin model is closely relevant to the icosahedral phase.

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New Wall Impaction Model for Diesel Spray (디젤분무의 새로운 벽면충돌모델)

  • Park K.
    • Journal of computational fluids engineering
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    • v.2 no.2
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    • pp.80-88
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    • 1997
  • A new wall impaction model for diesel spray is described in this paper. The gas phase is modelled in terms of the Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction. The liquid phase is modelled following the discrete droplet model approach. The droplet parcel contains many thousands of drops assumed to have the same size, temperature and velocity components. The droplet parcel equations of trajectory, momentum, mass and energy are written in Lagrangian form. The new drop-wall interaction model is proposed, which is based on experimental investigations on individual drops, and it is applied for the general non-orthogonal grid. The model is then assessed through comparison with experiments over a wide range of test conditions of sprays. The results are in good agreement with experimental data.

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Study on the FEA Model of the Linear Pulse Motor for Railway Application and Reduction of Thrust Ripple (철도차량 추진용 Linear Pulse Motor의 축소 모델 해석 및 추력 리플 저감 연구)

  • Seol, Hyun-Soo;Lee, Gang-Seok;Jeong, Geochul;Lee, Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.6
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    • pp.981-987
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    • 2017
  • In this paper, we describe the LPM structure with a two-phase, which is not used previously, and explain its operation principle. In order to predict the accurate performance of LPM reduction model, finite element model was derived and the back EMF of LPM reduction model was measured and compared. In order to investigate the thrust and normal force of the LPM reduction model, a driving circuit capable of applying two-phase pulse currents was constructed and the performance was predicted in conjunction with the finite element analysis model. Finally, the design considering actual LPM size was performed. Since the size of the reduction model is small, the field could be made of a permanent magnet. However, it is almost impossible to manufacture a permanent magnet to match the size and capacity of a real LPM for a vehicle, in terms of cost and writing. Therefore, the actual vehicle LPM was replaced by wound type that generates a magnetic field by applying current to the field winding, and the final model was derived using the reaction surface method.

Application of Forced Oscillation Technique for Pitch Dynamic Stability Derivatives of a Missile Model (미사일 모델의 피치 동안정미계수 측정을 위한 강제진동기법의 적용)

  • 김승필;조환기;백승욱
    • Journal of the Korea Institute of Military Science and Technology
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    • v.3 no.2
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    • pp.81-87
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    • 2000
  • This paper presents an application of forced oscillation technique to measure pitch dynamic stability derivatives of a missile model in the low speed wind tunnel. The missile model is oscillated by D.C. electric servomotor with constant amplitudes and frequencies. Phase shift is determined as the difference of peak values between input and output signals from the dynamic stability balance installed at the center of gravity of the model. Stability derivatives were calculated by using phase shifts, amplitudes, forcing moments and input frequencies. Test results show the proper usage of the force oscillation technique with good damping effects.

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Efficient Method of Processing Long-term Transactions for Distributed Environment (분산 환경에서 장기 트랜잭션의 효율적인 처리 방안)

  • 정지호;엄기환
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.10a
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    • pp.1007-1014
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    • 2003
  • It is important to integrate an enterprise application for automating of the business profess, which is responded by a flow of market environment. There are two categories of method that integrate enterprise applications. One is Synchronous Integration, and the other is Asynchronous Integration. EAI(Enterprise Application Integration) and Web service which of the asynchronous integration is focused in the automating method of the business process. After we construct the application integration for automating of the business process, we have to concern about managing of the business transaction. Many Organizations have proposed the process method of business transaction based on 2-phase commit protocol. But this method can′t supply the phase that classify the transaction by transaction weight. In this paper, we propose an efficient method of transaction process for business transactions, which is composed by ′Classify Phase′ that classify transactions. We called this model "3-Phase Commit Method Applied by Classify Phase", we design this model to manage an resource of enterprise efficiently. The proposed method is compared by the method based on 2-Phase commit that could be a problem of management the resource of enterprise, and the advantage of this method is certified to propose the solution of that problem.

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Numerical Simulation of Boiling 2-Phase Flow in a Helically-Coiled Tube (나선형코일 튜브 비등2상 유동 수치해석)

  • Jo J. C.;Kim W. S.;Kim H. J.;Lee Y. K.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.03a
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    • pp.49-55
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    • 2004
  • This paper addresses a numerical simulation of the flow and heat transfer in a simplified model of helically coiled tube steam generator using a general purpose computational fluid dynamic analysis computer code. The steam generator model is comprised of a cylindrical shell and helically coiled tubes. A cold feed water entered the tubes is heated up, evaporates. and finally become a superheated steam with a large amount of heat transferred continuously from the hot compressed water at higher pressure flowing counter-currently through the shell side. For the calculation of tube side two-phase flow field formed by boiling, inhomogeneous two-fluid model is used. Both the internal and external turbulent flows are simulated using the standard k-e model. The conjugate heat transfer analysis method is employed to calculate the conduction in the tube wall with finite thickness and the convections in the internal and external fluids simultaneously so as to match the fluid-wall-fluid interface conditions properly. The numerical calculations are peformed for helically coiled tubes of steam generator at an integral type pressurized water reactor under normal operation. The effects of tube-side inlet flow velocity are discussed in details. The results of present numerical simulation are considered to be physically plausible based on the data and knowledge from previous experimental and numerical studies where available.

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Numerical and experimental study for Datong coal gasification in entrained flow coal gasifier

  • Park, Y. C.;Park, T. J.;Kim, J. H.;Lee, J. G.
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 2001.11a
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    • pp.69-76
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    • 2001
  • The coal gasification process of a slurry feed type, entrained-flow coal gasifier was numerically predicted in this paper. By divding the complicated coal gasification process into several simplified stages suh as slurry evaporation, coal devolitilisation and two-phase reactions coupled with turbulent flow and two-phase heat transfer, a comprehensive numerical model was constructed to simulate the coal gasification process. The k-$\varepsilon$turbulence model was used for the gas phase flow while the Random-trajectory model was applied to describe the behavior of the coal slurry particles. The unreacted-core shrinking model and modified Eddy Break-Up(EBU) model were used to simulate the heterogeneous and homogeneous reactions, respectively. The simulation results obtained the detailed informations about the flow field, temperature inside the gasifier. Meanwhile, the simulation results were compared with the experimental data as function of $O_2$/coal ratio. It illustrated that the calculated carbon conversions agreed with the measured ones and that the measurd quality of the atngas was better than the calculated one when the $O_2$/coal ratio increases. The result was related with the total heat loss through the gasifier and uncertain kinetics for the heterogeneous reactions.

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NUMERICAL METHOD FOR THE TWO-FLUID THREE-FIELD MODEL ON AN UNSTRUCTURED MESH (비정렬격자 2-유체 3-상 유동 해석 기법)

  • Kim, J.;Park, I.K.;Cho, H.K.;Yoon, H.Y.;Jeong, J.J.
    • 한국전산유체공학회:학술대회논문집
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    • 2007.10a
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    • pp.243-248
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    • 2007
  • A three-dimensional (3D) unstructured hydrodynamic solver for transient two-phase flows has been developed. A two-fluid three-field model was adopted for the two-phase flows. The three fields represent a continuous liquid, an entrained liquid, and a vapour field. The hydrodynamic solver is for the 3D component of a nuclear system code and the component-scale analysis tools for transient two-phase flows. The finite volume method and unstructured grid are adopted, which are useful for the flows in a complicated geometry. The semi-implicit ICE (Implicit Continuous-fluid Eulerian) numerical scheme has been adapted to the unstructured non-staggered grid. This paper presents the numerical method and the preliminary results of the calculations. The results show that the numerical scheme is robust and predicts the phase change and the flow transitions due to boiling and flashing problems well.

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