• 디지털융복합연구
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• 제12권9호
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• pp.201-207
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• 2014

클라우드 환경에서 기업은 의사결정이나 기업의 정책을 결정하기 위해 데이터 통합 및 분석이 필요하다. 그러나 이 환경에서 새로운 시스템이 추가되면 데이터 통합 측면에서 기존 시스템이 가진 이질적인 특성 때문에 많은 비용과 시간이 필요로 하게 된다. 따라서 본 논문에서 멀티 데이터베이스 서비스를 위하여 DBaaS 허브 시스템을 제안한다. 이러한 DBaaS는 서로 다른 데이터베이스를 요구할 수도 있으며, 연관성이 있는 서비스를 위하여 데이터를 통합해야할 필요가 있다. DBaaS의 데이터 상호운용성 문제를 해결하기 위해 온톨로지를 이용한 메타 쿼리를 제안한다. 메타 쿼리는 실제 데이터에 접근하기 위한 쿼리가 아닌 상위의 쿼리이다. 이는 실제 데이터베이스에 접근할 때 온톨로지를 통하여 변환된 질의로 접근함으로써 데이터 통합을 기할 수 있다. 또한 메타 데이터를 이용하여 문서 지향 데이터베이스 시스템을 구축한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.945-948
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• 2005

In wireless and handheld platforms area, performance, power and cost are key metrics for product success. This is driving increasing levels of on-chip integration in state-of-the-art application processors. The purpose of this project is to optimize and design the energy-efficient embedded system that properly displays video and audio in real time. The requirements are for the media player to be capable of decoding real-time streaming video and audio with the least possible energy consumption for a variety of different clips at different resolutions. We implemented this Linux based multimedia player on Intel's PXA27x platform.

• Architectural research
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• 제7권1호
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• pp.1-9
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• 2005

The needs of collaboration among design participants spread in different locations is emphasized in the early design stage in order to not only save time and provide places to meet and talk, but also to save cost for those events as well: This is being realized by the Internet, which helps support a networked, integrated real-time multi-user environment. As the base for collaboration activities moves from physical places to cyberspace, the methods of connecting every participant by means of a computer technology have been desired and considered. This study aims at investigating today's collaboration technology in the architectural design process, especially focused on the early stages, in terms of temporal dimensions. In addition, major concepts for and previous efforts and tools of collaborative design have been examined, and a specific recommendation has been proposed for future development of collaborative architectural design systems: That is distributed collaboration, which is accessible and comprehensible to all the professionals in the building design team, which not only allows the sharing of information but also the sharing of understanding, and which facilitates the development of design tools for different aspects of the envisioned collaborative design environment.

• Structural Engineering and Mechanics
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• 제21권6호
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• pp.621-634
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• 2005

A direct transfer substructure method is presented in this paper for analyzing the dynamic characteristics and the seismic random responses of a series reactor. This method combines the concept of FRF (frequency response function) and the transfer matrix algorithm with the substructure approach. The inner degrees of freedom of each substructure are eliminated in the process of reconstruction and the computation cost is reduced greatly. With the convenient solution procedure, the dynamic characteristics analysis of the structure is valid and efficient. Associated with the pseudo excitation algorithm, the direct transfer substructure method is applied to investigating the seismic random responses of the series reactor. The numerical results demonstrate that the presented method is efficient and practicable in engineering. Finally, a precise time integration method is employed in performing a time-history analysis on the series reactor under El Centro and Taft earthquake waves.

• 제어로봇시스템학회논문지
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• 제8권12호
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• pp.1067-1075
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• 2002

The system error model for the compensation of the low-cost personal navigation system is derived and the error compensation method using GPS is also proposed. The walking navigation system (WNS) that calculates navigation information through walking detection has small error than INS, but the error also increases with time. In order to improve reliability of the system regardless of time, WNS is integrated with GPS. Since WNS is usually used in urban area, the blockage of CPS signal is frequently occurred. Therefore tightly coupled Kalman filter is used for the integration of WNS and GPS. In this paper, the system model for the design of tightly coupled Kかm filter is designed and measurement is linearized in consideration of moving distance error. It is shown by Monte Carlo simulation that the error is bounded even through the number of visible satellite is less than 4.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제3권2호
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• pp.161-171
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• 1999

Aerodynamic sensitivity analysis codes are developed via the hand-differentiation using a direct differentiation method and an adjoint method respectively from discrete two-dimensional compressible Navier-Stokes equations. Unlike previous other researches, Baldwin-Lomax algebraic turbulence model is also differentiated by hand to obtain design sensitivities with respect to design variables of interest in turbulent flows. Discrete direct sensitivity equations and adjoint equations are efficiently solved by the same time integration scheme adopted in the flow solver routine. The required memory for the adjoint sensitivity code is greatly reduced at the cost of the computational time by allowing the large banded flux jacobian matrix unassembled. Direct sensitivity code results are found to be exactly coincident with sensitivity derivatives obtained by the finite difference. Adjoint code results of a turbulent flow case show slight deviations from the exact results due to the limitation of the algebraic turbulence model in implementing the adjoint formulation. However, current adjoint sensitivity code yields much more accurate sensitivity derivatives than the adjoint code with the turbulence eddy viscosity being kept constant, which is a usual assumption for the prior researches.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1734-1735
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• 2011

In case of inspection on aluminum castings, traditional RT (Radiographic Testing) method have been utilized for its advantages in interpretation, cost and perpetual storage. But it has disadvantages like time consumption in film processing, low efficiency in storage and environmental pollution. In this thesis, a DRS (Digital Radiography System) utilizing X-Ray TDI Camera (Time Delay and Integration Camera) is developed. Inspections on aluminum castings are performed using the developed Digital Radiography System, DRS and reviewed if newly developed system can substitute for the traditional method.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제17권4호
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• pp.279-294
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• 2013

We are interested in an adaptive grid method for hyperbolic equations. A multiresolution analysis, based on a biorthogonal family of interpolating scaling functions and lifted interpolating wavelets, is used to dynamically adapt grid points according to the physical field profile in each time step. Traditional finite-difference schemes with fixed stencils produce high oscillations around sharp discontinuities. In this paper, we hybridize high-resolution schemes, which are suitable for capturing singularities, and apply a finite-difference approach to the scaling functions at non-singular points. We use a total variation diminishing Runge-Kutta method for the time integration. The computational cost is proportional to the number of points present after compression. We provide several numerical examples to verify our approach.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.364-368
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• 1992

The conventional loading process of workpieces for a CNC lathe is performaed either by human or by a general robot. It is not suitable for a general robot to load workpieces because of high price and inefficiency. Starting from the description of the environment around CNC lathes and the analysis ofloading process, we have developed the task-oriented loading manipulator. The characteristics of a loading manipulator are the following: to load/unload heavy workpieces, to decrease the whole porcess time. The air-chuck to load heavy workpiece has high clamping force and light weight. A loading manipulator has accomplished both the integration of independent automation techniques and cost-down effect of product. A loading manupulator developed in this project has been designed for general loading process. The loading manipulator is capable of carrying heavy payload with respect to weight of robot in short cycle time.

• Journal of Korea Trade
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• 제23권5호
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• pp.118-128
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• 2019

Purpose - This paper examines the international R&D contest in which the extent of intellectual property right (IPR) affects both the size of prize for the winning firm and the extent of positive spillover through cost of firms. Recognizing the possibility of incomplete protection of IPR, the present paper analyzes the effect of changes in the extent of IPR on payoffs to firms and social welfare. Design/methodology - This paper examines coordination of IPRs by countries in economic integration. The paper then develops a general model of international R&D contest with incomplete protection of IPR. An increase in the extent of IPR augments the share of the prize the winning firm can appropriate, while decreasing the positive cost externality. To derive sharper results, the paper considers the cases of linear and fixed spillovers. Findings - Under plausible assumptions, an increase in the IPR augments the payoff to each firm and the aggregate payoffs as well. The paper also shows that the number of firms participating in the R&D contest can be endogenously determined in the two-stage R&D contest. The higher the extent of cost spillover, and the larger the effective prize, the more firms participate in the international R&D contest. Originality/value - Existing studies assume that firms winning the R&D contest enjoy perfect IPR to the output of their R&D activities. This is a very restrictive assumption in that other firms can copy the new products or processes. By allowing for the incompleteness of the IPR, the present paper develops a more realistic model of R&D contest. The novelty of the present paper is to allow for the possibility that the higher extent of IPR increases the prize and decreases positive cost externality at the same time. The findings of the present paper can serve as a basis for government policy toward R&D activities of firms and protection of IPRs.