• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.556-560
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• 2011

Players of construction projects proceed with each work process by information gathering, modification and communication. Due to the complex and long-span lifecycle projects increased, it became more important to grasp this mechanism for the successful project performance in construction project. Hence, most project information management systems or knowledge management systems equip information retrieval system. There are two logic to infer the meaning of retrieval target; inductive reasoning and deductive reasoning. The former is based on metadata explaining the target and the later is based on relation between data. To infer the information flow, it is necessary to define the correlation between players and work processes. However, most established information retrieval systems are based on index search system and it is not focused on correlation between data but data itself. Thus, this research aims to research on process of information flow retrieval system for large-scale construction projects.

• 한국항해항만학회지
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• 제37권6호
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• pp.673-680
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• 2013

본 연구는 요트체험 활동 참여자들의 몰입도가 만족도 및 자아존중감에 미치는 영향에 관한 것으로서 우리나라 요트문화 및 레저산업의 대중화 실현에 기초자료를 제공하는데 그 목적이 있다. 이러한 연구 목적을 달성하기 위해 부산 울산 경남지역 주민을 대상으로 해양레저 아카데미 및 해양레저 체험 프로그램에 참여한 경험이 있는 대상자 총 428명을 모집단으로 선정하여 설문조사를 실시하였으며, 자료처리 방법은 빈도분석, 신뢰도분석, 타당도분석, 단순회귀분석, 다중회귀분석을 사용하였다. 이상과 같은 연구방법 및 자료분석의 결과를 통해 도출된 결론은 다음과 같다. 첫째, 요트체험 참가자들의 몰입도는 만족도에 정적인 영향을 미치는 것으로 나타났다. 둘째, 요트체험 참가자의 몰입도는 자아존중감(일반요인, 가정요인, 직장요인, 사회요인)에 정적인 영향을 미치는 것으로 나타났다. 셋째, 요트체험 참가자의 만족도는 자아존중감(일반요인, 가정요인, 직장요인, 사회요인)에 정적인 영향을 미치는 것으로 나타났다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.390-391
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• 2005

• 전기의세계
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• 제17권2호
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• pp.11-15
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• 1968

One of the most important methods used in the modern analysis of linear networks and systems is the signal flow graph technique, first introduced by S.J. Mason in 1953. In essence, the signal-flow graph technique is a graphical method of solving a set of simultaneous. It can, therefore, be regarded as an alternative to the substitution method or the conventional matrix method. Since a flow-graph is the pictorial representation of a set of equations, it has an obvious advantage, i.e., it describes the flow of signals from one point of a system to another. Thus it provides cause-and-effect relationship between signals. And it often significantly reduces the work involved, and also yields an easy, systematic manipulation of variables of interest. Mason's formula is very powerful, but it is applicable only when the desired quantity is the transmission gain between the source node and sink node. In this paper, author summarizes the signal-flow graph technique, and stipulates three rules for conversion of an arbitrary nonsource node into a source node. Then heuses the conversion rules to obtain various quantities, i.e., networks gains, functions and parameters, through simple graphical manipulations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.497-501
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• 2000

One of the way to derive design parameters of the fuel feeding system in satellite is to analyze unsteady flow of liquid propellant (hydrazine) in the propulsion system. During steady thruster firing the flow rate is constant: if a thruster valve is abruptly shut down among a sets of thrusters, pressure spikes much higher than the initial tank pressure occur. This renders the fuel flow unsteady, and the fluid pressure and flow rate to oscillate. If the pressure spikes are high enough, there are possibilities that propellant explosively decomposes, thruster valves are damaged, and adiabatic detonation of the hydrazine propellant is potentially incurred. Reflected shockwaves could also affect the calibration and operation of the pressure transducers. These necessitate the analysis of unsteady flow in the propulsion system design, and the calculation results obtained through some governing parameter variation are presented in this work.

• 한국콘텐츠학회논문지
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• 제12권1호
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• pp.166-175
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• 2012

<나탈리>(2010)와 <7광구>(2011)를 통해 한국 3D 영화제작의 가능성이 확인됐다. 그러나 동시에 한국 3D 영화제작 환경에서의 다양한 기술적, 제작과정상의 문제점이 도출되었다. 본 연구는 <7광구>의 3D 영화제작 사례를 분석한 결과이다. 분석은 주로 기술적인 오류와 제작 공정상의 파이프라인에서 드러난 문제점에 주목하여 이루어 졌다. <7광구>를 통해 얻은 제작 경험과 시행착오를 분석함으로써 향후 제작될 한국형 3D 영화의 제작진들에게 실무적인 연구결과를 전달하는 것이 본연구의 목적이다. 분석결과 <7광구>는 기술적인 완성도뿐만 아니라 효율적인 제작 파이프라인 구축에도 실패한 것으로 드러났다. 그럼에도 불구하고 <7광구>는 한국적인 3D 제작공정을 능동적으로 구축하려했다는 점에서 긍정적으로 평가 받는다.

• International Journal of Fluid Machinery and Systems
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• 제8권2호
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• pp.113-123
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• 2015

The efficiency of the ventilation system is a key point for durable and reliable electric generators. The design of such system requires a detailed understanding of the air flow in the generator. Computational fluid dynamics (CFD) has the potential to resolve the lack of information in this field. The present work analyses the air flow inside a generator model. The model is designed using a CFD-based approach, and manufactured by taking into consideration the experimental and numerical requirements and limitations. The emphasis is on the possibility to accurately predict and experimentally measure the flow distribution inside the stator channels. A major part of the work is focused on the design of an intake and a fan that gives an evenly distributed flow with a high flow rate. The intake also serves as an accurate flowmeter. Experimental results are presented, of the total volume flow rate, the total pressure and velocity distributions. Steady-state CFD simulations are performed using the FOAM-extend CFD toolbox. The simulations are based on the multiple rotating reference frames method. The results from the frozen rotor and mixing plane rotor-stator coupling approaches are compared. It is shown that the fan design provides a sufficient flow rate for the stator channels, which is not the case without the fan or with a previous fan design. The detailed experimental and numerical results show an excellent agreement, proving that the results reliable.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2558-2562
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• 2007

In the present work, flow characteristics analysis has been performed for steam turbine bypass control valve (single-path type). The numerical analysis is performed by solving three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations. Shear stress transport (SST) model is used as turbulence closure. Symmetry condition is applied at the mid plane of the valve while adiabatic condition is used at the outer wall of the cage. Grid independency test is performed to find the optimal number of grid points. The pressure and temperature distributions on the outer wall of the cage are analyzed. Mass flow rate at maximum plug opening condition is compared with the designed mass flow rate.

• International Journal of Aerospace System Engineering
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• 제4권1호
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• pp.9-12
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• 2017

In this study, an investigation on mechanical properties of flax natural fiber composite is performed as a precedent study on the design of eco-friendly structure using flax natural fiber composite. The Vacuum Assisted Resin Transfer Molding-Light (VARTML) manufacturing method is adopted for manufacturing the flax fiber composite panel. The VARTML is a manufacturing process that the resin is injected into the dry layered-up fibers enclosed by a rigid mold tool under vacuum. In this work, the resin flow analysis of VARTM manufacturing method is performed. A series of flax composite panels are manufactured, and several kinds of specimens cut out from the panels are tested to obtain mechanical performance data. Based on this, structural design of chemical storage tank for agricultural vehicle was performed using flax/vinyl ester. After structural design and analysis, the resin flow analysis of VARTM manufacturing method was performed.

• International Journal of Aerospace System Engineering
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• 제1권1호
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• pp.21-28
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• 2014

In this study, an investigation on mechanical properties of flax natural fiber composite is performed as a precedent study on the design of eco-friendly structure using flax natural fiber composite. The Vacuum Assisted Resin Transfer Molding-Light (VARTML) manufacturing method is adopted for manufacturing the flax fiber composite panel. The VARTML is a manufacturing process that the resin is injected into the dry layered -up fibers enclosed by a rigid mold tool under vacuum. In this work, the resin flow analysis of VARTM manufacturing method is performed. A series of flax composite panels are manufactured, and several kinds of specimens cut out from the panels are tested to obtain mechanical performance data. Based on this, structural design of chemical storage tank for agricultural vehicle was performed using flax/vinyl ester. After structural design and analysis, the resin flow analysis of VARTM manufacturing method was performed.