• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.267-270
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• 2001

A lot of efforts have been made to analyze the performance of the vehicle equipped with automatic transmission through simulation. It might be necessary to understand the different types of transmissions, i.e., different power flows, for different models. If there is a module that can be applied to different types of automatic transmission, it could be helpful to transmission-related engineers. This study has started up from this idea. The common bond graph has been obtained from several types of the automatic transmission. The overall generalized equations and kinematic constraint equations have been derived using virtual power sources on common bond graph. They are used to derive state equations and constraints. These equations have been applied as an application to the vehicle equipped with two simple planetary gear set type of Ravigneaux gear type automatic transmission. The state equation, kinematic constraints, and dynamic constraints have been derived in every gear and shift operation using overall generalized equations and kinematic constraint equations. Simulations for constraint speed running, standing-start running, rolling-start running, and LA-4 mode have been conducted to analyze the performance of the vehicle powertrain using GVPS(Generalized Vehicle Powertrain Simulation) program wit pull down menus.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.198-200
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• 2007

A linear generator driven by hydrogen (or other kind of fuel) combustion engine requires special consideration for starting because of its none-conventional way of operation. This study investigates the possibility of replacing mechanical (hydraulic) start-up with electrical motoring. Simulation study based on 1 kW prototype system shows that the mover position of a linear generator can be controlled with a proper current control of power converter.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.265-267
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• 1993

A control for Steam Generator (S/C) level is very difficult by automatic control mode but also manual control node during plant start up and/or low power level operation with the analog control system because of a non-nominal process responce. The goal of this study is to improve and computerize and applicate for KO-RI #1 Steam Generator level control system.

• Vacuum Magazine
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• v.4 no.1
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• pp.16-23
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• 2017

Recently, KSTAR, Korea's superconducting fusion energy research and development device, has succeeded in driving the high performance plasma for 70 seconds for the first time in the world. Continuous plasma operation technology is an essential factor for commercialization of fusion energy power generation. Therefore, this achievement is expected to play a major role in the research of fusion technology required for future fusion power plants. In order to operate the KSTAR, the discharge process in which the neutral gas is turned into the plasma should be preceded in the start-up (breakdown) phase of tokamak operation. This process essentially involves the vacuum environment in the tokamak device. KSTAR has successfully operated a vacuum pumping system to achieve the target level of the vacuum environment through a high temperature baking operation, a discharge cleaning process and boronization.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.687-700
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• 1995

The thermal-hydraulic transient analysis of the proposed CANDU-9 plant was peformed. Several major transients ore analyzed if they meet the heat transport system design requirements. The proposed heat transport system configuration and the preliminary sizes of system equipment are justified by analysis in terms of the fuel integrity and the high system pressure limit during transients. The compliance with AECB R-77 requirements for CANDU-9 reactor was estimated. The analysis results showed that for each postulated accident the peak pressure values in the reactor headers are within the acceptance criteria given in ASME code requirements and the fuel overheating is prevented. One pump start-up during the reactor start-up operation was analyzed to investigate the How reversal through the fuel channel, which is specific in the proposed CANDU-9 plant.

• Journal of the Korean Society of Combustion
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• v.19 no.3
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• pp.44-52
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• 2014

Solid oxide fuel cell(SOFC) makes electric power using hydrogen or reformed from methane and emits high temperature products that contain flammable species like hydrogen, carbon monoxide and methane which varies with operation condition. SOFC/gas turbine integrated system which uses thermal and chemical energy of the discharges is more efficient than SOFC itself. Burning character of the SOFC products will affect the efficiency and stability of the system. Experiments were conducted to know the characteristics of the flame for two typical composition of SOFC products, i.e. start-up and steady state composition. When coflowing air temperature was higher than $600^{\circ}C$, auto-ignitin occurred for both fuels. Though start-up fuel has higher contents of hydrogen, it makes longer flame than steady state composition. It was inferred that the amount of oxidizer necessary to burn makes this phenomenon. Steady state composition fuel was unstable since it contains lots of water. Nozzle that had 6 holes, distance between each hole was 16.7 times of hole diameter, improved the stability of the flame.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.61-69
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• 2002

To meet stringent LEV and ULEV emission standards, a considerable amount of development work was necessary to ensure suitable efficiency and durability of catalyst systems. The main challenge is to cut off the engine cold-start emissions. It is known that up to 80% of the total hydrocarbons(THC) are exhausted within the first five minutes in case of US FTP 75 cycle. Close-Coupled Catalyst(CCC) provides fast light-off temperature by utilizing the energy in the exhaust gas. However, if some malfunction occurred at engine operation and the catalyst temperature exceeds 1050$\^{C}$, the catalytic converter is deactivated and shows the poor conversion efficiency. This paper presents effEcts of engine operating conditions on catalytic converter temperature in a SI engine, which are the indications of catalytic deactivation. Exhaust gas temperature and catalyst temperature were measured as a function of air/fuel ratio, ignition timing and misfire rates. Additionally, light-off time was measured to investigate the effect of operating conditions. It was found that ignition retard and misfire can result in the deactivation of the catalytic converter, which eventually leads the drastic thermal aging of the converter. Significant reduction in light-off time can be achieved with proper control of ignition retard and misfire, which can reduce cold-start HC emissions as well.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.16 no.1
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• pp.1-19
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• 2021

The purpose of this research is to improve the investment success rate for startups in the water industry for the development of the entrepreneurial environment of the Korean water industry. In this research, we identified investment determinants through prior research and stratified them, and then surveyed the investor group at the beginning of the start-up using the FGI method, and determined the order of the investment determinants of investors. At the same time, we classified 41 start-ups related to the water industry into two groups: the group that received investment and the group that did not in the early stages of the start-up. Then we investigated the understanding of the investor's investment determinants, ranked them, and compared them by using the AHP technique. Through this, this research proposes five implications. First, it is important for start-ups in the early stages to receive seed investment to revitalize investment for startups in the water industry. For this, startups need to understand investors and prepare to attract investment with the perspective of angel investors rather than the perspective of VC investors. Second, Start-ups in the water sector should consider that the characteristics of the founder are important in order to receive seed investment, and also need to define their business at the industry and market level, and provide relevant rationale to meet the expectations of investors who value industry expertise and experience, and to increase the possibility of seed investment, which is important in the early stages of a startup. Third, institutions, such as K-water(Korea Water Resources Corporation), that support water industry startups need to conduct open innovation business opportunities discovery programs linked to startups so that startups currently participating in the startup support program could have business opportunities from the business infrastructure of platform-forming companies in the water industry. In particular, such institutions should help founders develop their industrial expertise and careers by supporting this type of start-up preparation process through the participation of in-house venture founders. Fourth, when K-water uses the government start-up support fund to discover and foster founders, it should increase initial contact with seed investors, conduct more thorough verification of business plans, and develop programs that use government start-up support funds to prepare a business suitable for seed angel investors. Fifth, K-water should support seed by connecting funds for initial investment among funds operated by itself. It is also necessary to develop a program that links the company receiving the seed investment with VC investment, not angel investment in cooperation with the VC fund operation entity participating as an LP so that companies that have attracted seed investment could attract follow-up VC investment.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.208-208
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• 2000

In realistic control systems, the nonlinear salutation attributes of the control actuator due to physical limitations should be taken into account. This nonlinear saturation of actuators may cause not only deterioration of the control performance but also a large overshoot during start-up and shut-down. As the overshoot increases, the system may become oscillatory unstable. In this paper, the supervisor implementation which guarantees good performance lot saturation operation and prevents reset wind-up is presented. Moreover, the sufficient conditions of the stability for saturated systems using supervisory control with a dynamic controller are provided in the discrete-time domain. A numerical example is illustrated to depict the efficiency of supervisory control for a typical saturated production-distribution system controlled by a discrete-time dynamic controller and to validate basic results by simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.233-247
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• 2011

With recent increase in growth without employment and unemployment rate, Business Incubator (BI), which is the birthplace of business start-up, is drawing much attention. Therefore, numerous studies had been carried out from the perspectives of efficient operation and performances of BI. Preceding studies at home and abroad were concentrated mainly on the effect of Critical Success Factors of BI on performance, or on internal operational programs or support services of BI. Recently, assertion that potential capacity of companies located in BI at the time of their commencement of occupancy imparts effect on the performance has been presented. Therefore, this Study, in order to pursue research on above issues, will, firstly, analyze the effect of the characteristics of evaluation of companies wishing to be located in BI conducted by each BI, and, secondly, regulation effect of characteristics of evaluation of companies wishing to be located in BI imparted on performance in connection with the work capabilities of BI and capabilities of manager. The results of analysis illustrated that the expertise, among the capabilities of CEO, imparts affirmative effect on the success rate of business start-up. Product competitiveness and marketability displayed affirmative effect on the success rate of business start-up when work capability (operational intensity) is applied. In particular, although the financing capability of CEO of the company located in BI, as an important factor, imparts negative effect on the success rate of business start-up, it implies affirmative regulation effect through the capabilities of manager.