• 한국IT서비스학회지
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• 제14권2호
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• pp.87-109
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• 2015

The IT outsourcing industry has been widespread for decades since the growth of the system integration industry stagnates and companies need to curtail expenses and improve the quality of IT services. According to previous studies on the success factors of the IT outsourcing, its transition phase is significant because of continuity of business and the handover of knowledge. Since a transition phase consists of several projects, but its goal is different from general projects, it needs special and professional management. Therefore, recent IT outsourcing business starts to introduce PMO (project management offices), of which success strongly depends on the competencies of the PMO. However, there are only few studies on which competencies of the PMO are important. In this paper, we suggest an evaluation model of transition PMO competencies derived using the repertory grid technique and the analytic hierarchy process. Additionally, we compare the differences between the views of several stakeholders on the importance of the competencies.

• 한국연소학회지
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• 제15권4호
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• pp.22-28
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• 2010

The Direct Quadrature Method of Moments (DQMOM) has been presented for the solution of population balance equation in the wide range of the multi-phase flows. This method has the inherently interesting features which can be easily applied to the multi-inner variable equation. In addition, DQMOM is capable of easily coupling the gas phase with the discrete phases while it requires the relatively low computational cost. Soot inception, subsequent aggregation, surface growth and oxidation are described through a population balance model solved with the DQMOM for soot formation. This approach is also able to represent the evolution of the soot particle size distribution. The turbulence-chemistry interaction is represented by the laminar flamelet model together with the presumed PDF approach and the spherical harmonic P-1 approximation is adopted to account for the radiative heat transfer.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2005-2011
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• 2003

Introducing the interfacial pressure jump terms based on the surface tension into the momentum equations of two-phase two-fluid model, the system of governing equations is turned mathematically into the hyperbolic system. The eigenvalues of the equation system become always real representing the void wave and the pressure wave propagation speeds as shown in the previous manuscript. To solve the interfacial pressure jump terms with void fraction gradients implicitly, the conventional semi-implicit method should be modified as an intermediate iteration method for void fraction at fractional time step. This advanced semi-implicit method (ASIM) then becomes stable without conventional additive terms. As a consequence, including the interfacial pressure jump terms with the advanced semi-implicit method, the numerical solutions of typical two-phase problems can be more stable and sound than those calculated exclusively by using any other terms like virtual mass, or artificial viscosity.

• Journal of Information Display
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• 제8권3호
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• pp.22-28
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• 2007

We reported the diffraction analysis of the liquid crystal (LC) binary gratings and the surface anchoring energies for planar and homeotropic alignments. The planar and homeotropic anchoring energies were directly derived based on the linearly distorted director distribution near domain boundaries, in which the distorted lengths correspond to the extrapolation lengths into both planar and homeotropic regions. From the diffraction analysis for the LC binary gratings with various grating periods based on the linearly graded phase model, both distorted lengths into planar and homeotropic regions were simultaneously obtained. In this work, the planar and homeotropic anchoring energies were found to be about $1.4\;{\times}\;10^{-4}\;J/m^2$ and $0.9\;{\times}\;10^{-5}\;J/m^2$, respectively.

• Structural Engineering and Mechanics
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• 제32권2호
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• pp.235-249
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• 2009

The response of concrete structures subjected to shock and blast load involves a rapid transient phase, during which material breach may take place. Such an effect could play a crucial role in determining the residual state of the structure and the possible dispersion of the fragments. Modelling of the transient phase response poses various challenges due to the complexities arising from the dynamic behaviour of the materials and the numerical difficulties associated with the evolving material discontinuity and large deformations. Typical modelling approaches include the traditional finite element method in conjunction with an element removal scheme, various meshfree methods such as the SPH, and the mesoscale model. This paper is intended to provide an overview of several alternative approaches and discuss their respective applicability. Representative concrete material models for high pressure and high rate applications are also commented. Several recent application studies are introduced to illustrate the pros and cons of different modelling options.

• Advances in materials Research
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• 제12권2호
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• pp.101-118
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• 2023

The purpose of this paper is to study the effects of magnetic field and gravitational field on fiber-reinforced thermoelastic medium with memory-dependent derivative. Three-phase-lag model of thermoelasticity (3PHL) is used to study the plane waves in a fiber-reinforced magneto-thermoelastic material with memory-dependent derivative. A gravitating magneto-thermoelastic two-dimensional substrate is influenced by both thermal shock and mechanical loads at the free surface. Analytical expressions of the considered variables are obtained by using Laplace-Fourier transforms technique with the eigenvalue approach technique. A numerical example is considered to illustrate graphically the effects of the magnetic field, gravitational field and two types of mechanical loads(continuous load and impact load).

• KSBB Journal
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• 제9권3호
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• pp.279-286
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• 1994

Fe(III) IDA -PEG/ dextran 액 이상 분계 시스템에서 phosphoprotein의 분배 예측을 위한 모델식이 유도되었다. 본 모델식에는 단백칠 분배에 수소이온과 hydroxide 이온의 저해효과가 포함되어 었다. 표변에 각각 1,27~의 phosphoryl 그 룹을 갖고 있는 ovalbumin의 AI, A2, 성분을 정제한 후 단백질 분배 실험을 수행하였으며 실 험결과와 모텔식에의한 예측이 잘 얼치하는 것 을 확인하였다. Fe(III)IDA-PEG와 단백질 표면 p phosphoryl group과의 결합상수는 PEG 상과 dextran상에 셔 각각 $6.1{\times}, 10^3M^{-1} and 2.3{\times}10^4M^{-1}$이었으며,이것은 Cu(II)IDA-PEG와 단백질 표면 histidine과의 결합상수 보다 3-5배 높은 값이 였 다.

• 대한조선학회논문집
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• 제53권5호
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• pp.371-379
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• 2016

In the ship design process, ship motion and propulsion performance in sea waves became very important issues. Especially, prediction of ship propulsion performance during real operation is an important challenge to ship owners for economic operation in terms of fuel consumption and route-time evaluation. Therefore, it should be considered in the early design stages of the ship. It is thought that the averaged value and fluctuation of effective inflow velocity to the propeller have a great effect on the propulsion performance in waves. However, even for the nominal velocity distribution, very few results have been presented due to some technical difficulties in experiments. In this study, flow measurements near the propeller plane using a stereo PIV system were performed. Phase-averaged flow fields on the propeller plane of a KVLCC2 model ship in waves were measured in the towing tank by using the stereo PIV system and a phase synchronizer with heave motion. The experiment was carried out at fully loaded condition with making surge, heave and pitch motions free at a forward speed corresponding to Fr=0.142 (Re=2.55×106) in various head waves and calm water condition. The phase averaged nominal velocity fields obtained from the measurements are discussed with respect to effects of wave orbital velocity and ship motion. The low velocity region is affected by pressure gradient and ship motion.

• 한국시뮬레이션학회논문지
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• 제25권4호
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• pp.77-84
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• 2016

본 논문은 시스템에 대한 기능 중심의 신뢰도 예측을 수행하기 위한 모델링 방법론을 제안한다. 신뢰도 예측에 대한 다양한 기존 연구들이 있지만, 이 연구들의 공통점은 하드웨어 중심으로 신뢰도 예측을 수행하였다는 점이다. 신뢰성이 제품이 주어진 사용 조건 아래서 의도하는 기간 동안 정해진 기능을 성공적으로 수행하는 능력이라고 정의되는 점에서 보았을 때, 하드웨어 중심의 신뢰도는 논리적 모순을 가진다. 본 논문에서는 기능 중심의 신뢰도 예측을 위해 4-단계 모델링 절차(four-phase modeling procedure)를 제안하였다. 제안되는 모델링 방법론은 네 개의 모델로 구성된다; 1) 구조적 블록 모델(structure block model), 2) 기능 블록 모델 (function block model), 3) 장치 모델 (device model), 그리고 4) 신뢰성 예측 모델 (reliability prediction model). 본 논문에서는 제안하는 모델링 방법론을 이용하여 전자식 안정기에 대한 기능 중심의 신뢰도 예측을 수행하였으며, 하드웨어의 신뢰도를 결정하기 위해 신뢰도 예측 규격 중 하나인 MIL-HDBK-217F를 이용하였다.

• 한국세라믹학회지
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• 제38권10호
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• pp.881-885
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• 2001

Kinetics and mechanisms of intermediate phases formation in $Ba(Mg_{1/3}Ta_{2/3})O_3$, obtained by a solid state reaction were studied. $Ba{Ta_2}{O_6}$ and ${Ba_4}{Ta_2}{O_9}$ as intermediate products were first formed at $700^{\circ}C$. $Ba(Mg_{1/3}Ta_{2/3})O_3$ was appeared at $800^{\circ}C$. Several reactions take place on heating process. $Ba{Ta_2}{O_6}$ is found at the first stage of the reaction, and then $Ba{Ta_2}{O_6}$ or ${Ba_4}{Ta_2}{O_9}$ react with MgO to form $Ba(Mg_{1/3}Ta_{2/3})O_3$. The reaction of $Ba(Mg_{1/3}Ta_{2/3})O_3$ formation does not complete until fired at $1350^{\circ}C$ for 60 min. The kinetics of solid-state reaction between powdered reactants was controlled by diffusion mechanism, and can be explained by the Jander's model for three-dimensional diffusion.