• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.69-77
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• 2020

A quasi one-dimensional multi-phase reaction flow analysis code is developed for the performance analysis of liquid pintle thrusters. Unsteady flow field, droplet evaporation, finite reaction and film cooling models are composed as the major models of the performance analysis. The droplet vaporization takes account of Abramzon's vaporization model, and the combustion employs a flamelet model based on detail chemical reactions. Shine's model is applied for the film cooling calculation. To verify each model, the Sod shock tube, single droplet vaporization, kerosene droplets combustion, and film length are evaluated.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2011.04a
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• pp.153-158
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• 2011

According to the change of life environment and economic growth, the more city has highly developed, the more concentrated urban function. That is, city is required for adding infra structure. But, both of limited land resources and financial problems made it impossible to add infra structure. So, the necessity of multi-dimensional planning of urban infra structure was recognized. Especially, In Urban residential area, in order to secure parking area, It is on the increase that mixed-use of the playground of school in the high density area and the empty space of park. School and park is closely connected with town community, playing a central role on town life. For this reason, they are highly demanded for providing space in the urban residential area and also expected to be effective. However, people using park and school are almost young students and the elderly, it needs to consider not only the parking convenience also the safety of users in design process. In this study, we analysed the physical characteristics and the utilization of mixed-use of school and park. and then evaluated the case in the point of convenience and safety. For this, first we selected the case among the sites constructed in seoul, and divided 2type of 'slope type' and 'flatland type'. The meaning of this study is to suggest elementary standards for design in the point of multi-dimensional land use planning.

• Journal of Digital Convergence
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• v.13 no.3
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• pp.75-84
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• 2015

As the service industry has been getting increased attention as the core for the national economic growth, in order to promote growth and development of the industry, in-depth research on the workers in the industry has been timely called for. Therefore current study aims to explore the effect of leadership style on organizational citizenship behavior(ie OCB) for increased productivity of workers in the service industry, and the role of multi-dimensional justice in the relationship between them. The findings suggest that transformational and transactional leadership both have positive effect on OCB, implying that application of leadership style that is appropriate to the context may be more important, Also, mediation test of multi-dimensional justice resulted partial mediation effect except for the procedural justice in the relationship between transformational leadership and OCB.

• Journal of computational fluids engineering
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• v.21 no.2
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• pp.25-31
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• 2016

In this paper, a study on the development of OpenFOAM grid generation program for two-dimensional flow analysis is described. By using the pre-processor(eMEGA) of EDISON_CFD system, grids for OpenFOAM flow calculation were obtained. Resultant two-dimensional grids were used to calculate flow fields by applying simpleFoam, one of the OpenFOAM's popular solvers, and the obtained flow results were compared with theoretical and experimental data available. Also grids generated by present program were compared with grids by a commercial pre-processor Pointwise for the purpose of verification. Verification work includes three cases(single block, O-type single block, and multi block grid), and all results show reasonable matches. According to the current achievement, it can be concluded that OpenFOAM grid can be constructed conveniently by using eMEGA with GUI.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.464-469
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• 1999

Recently, the need for designing multi-stage gear drive has been increased as the hear drives are used more in the applications with high-speed and small volume. The design of multi-stage gear drives includes not only dimensional design but also configuration design of various machine elements. Until now, however, the researches on the design of gear drives are mainly focused on the single-stage gear drives and the design practices for multi-stage gear drives, especially in configuration design activity, mainly depend on the experiences and 'sense' of the designer by trial and error. We propose a design algorithm to automate the dimension design and the configuration design of multi-stage gear drives. The design process consists of four steps. The number of stage should be determined in the first step. In second step, the gear ratios of each reduction stage are determined using random search, and the ratios are basic input for the dimension design of gears, which is performed by the exhaustive search in third step. The designs of gears are guaranteed by the pitting resistance and bending strength rating practices by AGMA rating formulas. In configuration design, the positions of gears are determined to minimize the volume of gearbox using simulated annealing algorithm. The effectiveness of the algorithm is assured by the design example of a 4-stage gear drive.

• Proceedings of the Korean Geotechical Society Conference
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• 1994.09a
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• pp.149-157
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• 1994

In this study two dimensional visco-plastic finite element model capable of handling the multi-step excavation was developed for investigating the effect of excavation support sequences on the behavior of underground openings in the jointed rock mass. First, the finite element model which is capable of handling the multi-step excavation is developed and verified. And then the model is combined with visco-plastic joint model. Ubiquitous joint pattern was considered in the model and joint properties in cach set were assumed to be indentical. Passive, full-grouted rockbolts were cosidered in the numerical model. The visco-plastic deformations of joints and rockbolts were assumed to be governed by Mohr-Conlomb and von Mises yield criteria, respectively. With the ability of removing elements, the model can simulate the multi-step excavation-suppport sequences. The reliability and applicability of the model to the stability analysis for the underground excavation in pratice was checked by simulating the behavior of underground crude oil storage caverns under construction.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.5
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• pp.68-77
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• 1994

The authors apply the transfer influence coefficient method to the 3-dimensional vibration analysis of beam with multi-joints and formulate a general algorithm to analysis the longitudinal, flexural and torsional coupled free vibration. In this paper, the structure, which is mainly founded in the robot arms, cranes and so on, has some crooked parts, subsystems and joints but has no closed loop in this system. It is modeled as the beam of a distributed mass system with massless translational, rotational and torsional springs in each node, and joint elements of release or roll at which node the displacement vector is discontinuous. The superiorty of the present method to the transfer matrix method in the computation accuracy was confirmed by the numerical computation results. Moreover, we confirmed that boundary and intermediate conditions could ve controlled by varying the values o the spring constants.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.3
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• pp.256-266
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• 1997

The authors apply the transfer influence coefficient method to the 3. dimensional vibration analysis of beam with multi - joints and formulate a general algorithm to analyse the longitudinal, flexural and torsional coupled forced vibration. In this paper, a structure which is mainly found in the robot arms, cranes and so on, has some crooked parts, subsystems and joints, but has no closed loop in this system. It is modeled as the beam of a distributed mass system with massless translational, rotational and torsional springs in each node, and joint elements of release or roll at node which the displacement vector is discontinuous. The superiority of the present method to the transfer matrix method in the computation accuracy was confirmed from the numerical computation results. Moreover, we confirmed that boundary and intermediate conditions could be controlled by varying the values of the spring constants.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.996-1007
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• 2019

We investigated the influence of the aspect ratio (H/R) of the oxide layer on the reactor vessel heating in three-layer configuration. Based on the analogy between heat and mass transfers, we performed mass transfer experiments to achieve high Rayleigh numbers ranging from $6.70{\times}10^{10}$ to $7.84{\times}10^{12}$. Two-dimensional (2-D) semi-circular apparatuses having the internal heat source were used whose surfaces of top, bottom and side simulate the interfaces of the oxide layer with the light metal layer, the heavy metal layer, and the reactor vessel, respectively. Multi-cell flow pattern was identified when the H/R was reduced to 0.47 or less, which promoted the downward heat transfer from the oxide layer and possibly mitigated the focusing effect at the upper metallic layer. The top boundary condition greatly affected the natural convection of the oxide layer due to the presence of secondary flows underneath the cold light metal layer.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.622-629
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• 2009

Modern figurative work is designed to have more creativity and characteristic traits by pure thought of the formative ceramic arts. In compliance with the demand which is various the design development could be satisfied an individuality and a taste is become accomplished. In this view, this study looks over expressive aspect of Cubism to present partition as a independent formative ceramic arts is able to contribute emotionally to our whole lives. In this procedure, this work is produced to express a three-dimensional effect and a spatial effect, approaching a figurative side. This is to overcome the limitation of Cubism art expressed in a two-dimensional surface in spite of its multi-dimensional observation of a given object. Accordingly, this study tries approaching pre-understanding of expressive aspect of Cubism which was the important turning-point in 20c art and expansion of the modern ceramic art field before producing the work. This study shows the possibility to become a creative and practical ceramic art work, approaching the new point of view breaking from the established conception. Consequently, the field of ceramic art could be expanded to a part of modern ceramic art as an object of study in art of life.