• 한국IT서비스학회지
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• 제15권1호
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• pp.299-319
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• 2016

This study first introduces platform services and their business models. On the basis of the concepts of business ecosystem, we present a framework for distinguishing types of the platform service business models. Two key characteristics of business ecosystems-ecosystem configuration and value production process-are employed as fundamental dimensions for constructing typology. In particular, we also present the notion of value ecosystem, where not a single platform provider but a federation of platforms constitutes a virtual platform and completes a service system. The value ecosystem represents two distinct types of platform service business models : meta-platform ecosystem and platform coalition ecosystem. They show different governance structure in the platform federation and service flows across the ecosystem. We present detailed analyses of these two value ecosystems focusing on relevant cases of e-payment FinTech : Apple Pay as an example of meta-platform and Kakao Pay for platform coalition. Our conceptual typology contributes to platforms' proper strategy formulation and presents policy implications to, for example, platform neutrality.

• 대한교통학회지
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• 제13권1호
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• pp.95-110
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• 1995

n this research neural -based model was developed to forecast link travel times , And it is also compared wiht other time series forecasting models such as Box-Jenkins model, Kalman filter model. These models are validated to evaluate the accuracy of models with real time series data gathered by the license plate method. Neural network's convergency and generalization were investigated by modifying learning rate, momentum term and the number of hidden layer units. Through this experiment, the optimum configuration of the nerual network architecture was determined. Optimumlearining rate, momentum term and the number of hidden layer units hsow 0.3, 0.5, 13 respectively. It may be applied to DRGS(dynamic route guidance system) with a minor modification. The methods are suggested at the condlusion of this paper, And there is no doubt that this neural -based model can be applied to many other itme series forecating problem such as populationforecasting vehicel volume forecasting et .

• International Journal of Aeronautical and Space Sciences
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• 제17권2호
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• pp.175-183
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• 2016

A poroelastic composite material, containing different material phases and filled with fluids, serves as a model to formulate the overall ablative behaviors of such materials. This article deals with the assessment of variation in nondeterministic poroelastic properties of two-phase composite materials using micromechanical representative volume element (RVE) models. Considering the configuration and arrangement of pores in a matrix phase, various RVEs are modeled and analyzed according to their porosity. In order to quantitatively investigate the effects of microstructure, changes in effective elastic moduli and poroelastic parameters are measured via finite element (FE) analysis. The poroelastic parameters are calculated from the effective elastic moduli and the pore-pressure-induced strains. The reliability of the numerical results is verified through image-based FE models with the actual shape of pores in carbon-phenolic ablative materials. Additionally, the variation of strain energy density is measured, which can possibly be used to evaluate microstress concentrations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.65-67
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• 2001

Because of the difficulty of acquiring new generation sites and right- of-way, additional units have been added to the existing generation sites and the transmission system has been developed into highly meshed configuration. The reliable operation of power systems has been restricted by this system characteristics. The enhancement of system analysis techniques and establishment of appropriate measures have been required in this situation. In addition the deregulation of electric power industry in Korea would give rise to better tools for power system analysis and control. In this paper, dynamic models were developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.68-70
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• 2001

Because of the difficulty of acquiring new generation sites and right- of-way, additional units have been added to the existing generation sites and the transmission system has been developed into highly meshed configuration. The reliable operation of power systems has been restricted by this system characteristics. The enhancement of system analysis techniques and establishment of appropriate measures have been required in this situation. In addition the deregulation of electric power industry in Korea would give rise to better tools fur power system analysis and control. In this paper, dynamic models were developed and stability studies were implemented using developed dynamic models of EUROSTAG and compared with the simulation results of PSS/E.

• Computers and Concrete
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• 제13권2호
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• pp.271-290
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• 2014

In this study, structural irregularities in plan, which has a considerable effect on earthquake behavior of buildings, have been investigated in detail based on Turkish Earthquake Code 2007. The study consists of six main parametric models and a total of 144 sub-models that are grouped based on RC structural systems such as frame, frame + rigid core, frame with shear wall, and frame with shear wall + rigid core. All models are designed to have both symmetrical plan geometry and regular rigidity distribution. Changes in the earthquake behavior of buildings were evaluated according to the number of storeys, number of axes and the configuration of structural elements. Many findings are obtained and assessed as a result of the analysis for each structural irregularity. The study shows that structural irregularities can be observed in completely symmetric buildings in terms of plan geometry and rigidity distribution.

• 한국CDE학회논문집
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• 제21권1호
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• pp.78-89
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• 2016

When a plant owner requests plant 3D CAD models in the format that a shipbuilding company does not use, the shipyard manually re-models plant 3D CAD models according to the owner's requirement. Therefore, it is important to develop a technology to compare the re-modeled plant 3D CAD models with original ones and to quantitatively evaluate similarity between two models. In the previous study, we developed a graphic user interface (GUI)-based comparison system where a user evaluates similarity between original and re-modeled plant 3D CAD models for piping design at the level of unit. However, an offshore plant consists of thousands of units and thus a system which compares several plant 3D CAD models at unit-level without human intervention is necessary. For this, we developed a new batch model comparison system which automatically evaluates similarity of several unit-level plant 3D CAD models using an extensible markup language (XML) file storing file location and name data about a set of plant 3D CAD models. This paper suggests system configuration of a batch-mode-based comparison system and discusses its core functions. For the verification of the developed system, comparison experiments for offshore plant 3D piping CAD models using the system were performed. From the experiments, we confirmed that similarities for several plant 3D CAD models at unit-level were evaluated without human intervention.

• 한국항공운항학회지
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• 제23권2호
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• pp.1-6
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• 2015

The RSA is intended to prevent the following five types of events from becoming an accident: landing overruns, landing undershoots, landing veer-offs, takeoff overruns and takeoff veer-offs. The improved models are based on evidence from worldwide accidents and incidents that occurred during the past 27 years. The analysis utilizes historical data from the specific airport and allows the user to take into consideration specific operational conditions to which movements are subject, as well as the actual or planned RSA conditions in terms of dimensions, configuration, type of terrain, and boundaries defined by existing obstacles. This paper shows how to apply the improved models for Risk Assessment of Runway Safety Areas (Airport cooperative research program(ACRP) Report 50) into an airport and the outcome differences between the old models based on ACRP report 3-Analysis of aircraft overrun and undershoots for runway safety areas and the new models from ACRP report 50 in the specific airport.

• 에너지공학
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• 제12권2호
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• pp.109-117
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• 2003

신규 발전소 부지 및 송전선 경과지 확보의 어려움 때문에 신규 발전기들은 기존의 발전단지에 건설되고 송전망은 더 복잡한 망의 형태로 구성되고 있다. 이러한 구조적인 특징은 전력계통의 운용의 신뢰성에 제약을 발생시킨다. 이러한 문제를 해결하기 위해서 전력계통의 해석의 고도화와 적절한 대책이 요구된다. 또한 현재 진행중인 전력산업의 구조 개편 이후, 신뢰성과 경제성을 동시에 추구하여야하는 경쟁적 전력시장에서의 계통해석 결과에 따른 비용 발생시에 책임소재의 투명성과 해석결과에 대한 검증이 필요하게 되어 계통해석 기술의 고도_화와 이를 구현하기 위한 해석 프로그램의 다변화가 절실하게 요구된다. 본 논문에서는 대규모 전력계통 해석 프로그램인 EUROSTAG의 발전기 제어계 계통 의 모델을 개발하였고, 성능을 입증하기 위해서 현재 전력회사에서 사용되는 PSS/E와 시뮬레이션 결과를 비교하였다.

• 한국자동차공학회논문집
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• 제23권3호
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• pp.287-291
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• 2015

This study investigates the result of thermal stress analysis on disk rotor by classes at bike brake. In the analysis result of thermal deformation at the steady state, maximum deformations at models 1, 2 and 3 are 0.14347mm, 0.15823mm and 0.16028mm respectively. The deformation becomes larger as the field goes on from the center to the outside at disk rotor. As there are models 1, 2 and 3 in the order of maximum deformation, model 1 has safest among three models. In the analysis result of thermal stress at steady and transient states, there are models 1, 2 and 3 in the order of maximum stress. Model 1 becomes most excellent on strength and safety among three models. By using the analysis result of disk rotor model at bike disk, it is possible to design the model applied practically at the safe driving of bike.