• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.120-127
• /
• 2017

High temperature oxygen and water vapor was generated from catalytic decomposition of rocket grade highly concentrated hydrogen peroxide, and monopropellant thruster system was developed and applied into space propulsion system. In this research, background research and conceptual design of underwater propulsion system using catalytic decomposition of hydrogen peroxide was progressed. Two types of system was designed with different steam injection methods. Propulsion system that has ring-type steam injector was manufactured and performance estimation of system was performed with different nozzle exit area. Performance evaluation with central steam injection type jet engine will be progressed in the future.

• Journal of Korea Water Resources Association
• /
• v.34 no.5
• /
• pp.473-486
• /
• 2001

The WGR model was developed to represent meso-scale precipitation. As a conceptual model, this model shows a good link between atmospheric dynamics and statistical description of meso-scale precipitation(Waymire et al., 1984). However, as it has maximum 18 parameters along with its non-linear structure, its parameter estimation has been remained a difficult problem. There have been several cases of its parameter estimation for different fields using non-linear programming techniques(NLP), which were also difficult tasks to hamper its wide applications. In this study, we estimated the WGR model parameters of the Han river basin using the genetic algorithm(GA) and compared them to the NLP results(Yoo and Kwon, 2000). As a result of the study, we can find that the sum of square error from the GA provide more consistent parameters to the seasonal variation of rainfall. Also, we can find that the higher rainfall amount during summer season is closely related with the arrival rate of rain bands, not the rain cell intensity.

• Journal of Radiation Protection and Research
• /
• v.34 no.1
• /
• pp.1-7
• /
• 2009

It is expected that a substantial amount of spent fuels will be transported from the four nuclear power plant (NPP) sites in Korea to a hypothetical centralized interim storage facility or a final repository in the near future. The cost for the transportation is proportional to the amount of spent fuels. In this paper, a cost estimation program is developed based on the conceptual design of a transportation system and a logistics analysis. Using the developed computer program, named as CASK, the minimum capacity of a centralized interim storage facility (CISF) and the transportation cost for PWR spent fuels are calculated. The PWR spent fuels are transported from 4 NPP sites to a final repository (FR) via the CISF. Since NPP sites and the CISF are located along the coast, a sea-transportation is considered and a road-transportation is considered between the CISF and the FR. The result shows that the minimum capacity of the interim storage facility is 15,000 MTU.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.5
• /
• pp.553-558
• /
• 2011

This study have goal with conceptual design for offshore structures of high pressure drop control valve for localization valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25. In order to localize the Offshore structures high pressure drop control valve. This study is numerical analysis for zambil offshore project of high pressure drop control valve. The solver which ANSYS workbench used for offshore structures analysis. The working fluids assumed the glycerin(C3H8O3). The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and disk structure. In this study a multi-disk of high pressure drop control valve is designed and manufactured. Then, the flow rate and high pressure dorp of fluids flowing in the high pressure drop control valve is CAE. So, this system can be easily substituted for the existing zambil offshore project system. Finally, safety estimation for trim design of high pressure drop control valve for offshore structures.

• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.7
• /
• pp.543-551
• /
• 2016

This paper presents the analysis and implementation of traveling surface characteristics test equipment using optical mice in connection with the velocity estimation of a mobile robot equipped with optical mice. In the traveling surface characteristics test equipment, a traveling surface sample is made to rotate toward stationary optical mice instead of a mobile robot equipped with optical mice moving over a traveling surface. First, the conceptual design and operational principle of the traveling surface characteristics test equipment is explained. Second, the velocity kinematics of the traveling surface characteristics test equipment is formulated; based on this, the parameter setting of the traveling surface characteristics test equipment is described. Third, the implementation of the traveling surface characteristics test equipment is described in detail, including the mechanical design and construction and the hardware and software development. Fourth, using the prototype of the traveling surface characteristics test equipment, the experimental results of the statistical parameter extraction for different traveling surface samples are given. Finally, some potential usages of the traveling surface characteristics test equipment are discussed.

• Journal of the Society of Naval Architects of Korea
• /
• v.53 no.2
• /
• pp.92-100
• /
• 2016

A comparative method is applied to evaluate well-known formulas for estimating the size of supercavities of axisymmetric cavitators for the supercavitating underwater vehicle. Basic functional forms of these formulas are derived first for the cavity diameter from a momentum integral estimate and second for the cavity length from an asymptotic analysis of inviscid supercavity flows. The length and the diameter of axisymmetric supercavities estimated by each formula are compared, with available experimental data for a disk and a 45° conical cavitators, and also with computational results obtained by a CFD code, ‘fluent’, for conical cavitators of wide range of cone angles. Results for estimating the length and the diameter of the supercavities show in general a good agreement, which confirms the size of the supercavities for disk and conical cavitators can be estimated accurately by these simple formulas of an elementary function of cavitation number and drag coefficient of the cavitator. These formulas will be useful for from conceptual design of the cavitator to real-time control of the supercavitating underwater vehicle.

• International Journal of Human Ecology
• /
• v.4 no.2
• /
• pp.55-75
• /
• 2003

The purpose of this study was to investigate the effect of employment related factors on household savings for precautionary purposes when controlling for financial security and to compare the results between the two different economic periods. A conceptual framework was developed based on the precautionary saving theory, the family stress theory, and previous empirical studies. As a self-insurance, a measure of security funds were developed and used as the dependent variable. Using data on working households in the 1992 and the 1998 Survey of Consumer Finances (SCF), a MLE estimation was conducted on the pooled data. The 1992 and 1998 data were used to reflect periods of economic recession and expansion, respectively. The results suggested that factors representing resources played the most significant role in determining the amount of security funds. Some of the employment related factors, preferences, financial security, and race were also significantly affected the amount of security funds. The results suggested that stable employment conditions were important for households to accumulate security funds. Households with more human resources and financial resources had a larger amount of security funds than those that had less human and financial resources. From the findings, implications for research, policies, and financial educators had been suggested.

• The Journal of Society for e-Business Studies
• /
• v.6 no.1
• /
• pp.55-67
• /
• 2001

Over the past decade, the topic of work breakdown structure (WBS) has gained an increasing amount of attention from information technology Professionals as an effective tool for managing the complexity of a large-scale information system development project. It is a method for planning and controlling a large-scale information system development. A WBS provides the basis for project organization, cost estimation, task scheduling, and contract management. Based on the authors' practical experience, this paper discusses how to establish a specific WBS and some considerations for developing a well-defined WBS. The model of WBS suggested in this study will provide useful insight and guidelines for establishing the spec-ific WBS for a large-scale information systems development.

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.1
• /
• pp.104-114
• /
• 2006

Recently, the PPP (Public-Private-Participate) program on water and wastewater services in Korea has been under an active debate. However, the controversy has reached the limits of getting more valuable implications from past foreign experience beyond conceptual and/or qualitative case studies. This paper analyze scientifically and quantitatively the Buenos Aires Water Concession Project focused on propriety of the contract using system dynamics modeling. The results show that Buenos Aires's Project has several problems in the contract phase even though Argentina government spent much time to design it. Analysis results suggest that estimation of K factor considering delay effect and future uncertainty, reduction of the first fixed terms of contract, etc., are needed for a proper contract.

• 한국전산유체공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.87-91
• /
• 2005

A conceptual design for the movable roll vane system is done for the roll stability control of KSLV-I. The control effectiveness of the roll vanes is estimated using the numerical simulation. The hinge location is selected to minimize the torque requirement at the maximum dynamic pressure condition, and the maximum torque of 3.0 kN-m is found to be required to actuate the roll vanes for the entire range of operation. An electro-mechanical actuator system which is composed of a DC motor, the speed reducers, the battery package and the controller is designed using the given requirements, the maximum torque of 3.0 kN-m, the maximum deflection angle of 25 deg. and the maximum angular velocity of 30 deg/sec. More detailed design to make more compact and highly efficient system will be done in the future.