• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.78-81
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• 2008

A numerical study of the unsteady flow in an over-expanded thrust optimized contour and compressed truncated perfect rocket nozzle is carried out in present paper. These rocket nozzles are subject to flow separation in transient phase at engine start-up and/or engine shut-down. The separation flow structures at different pressure ratios are observed. The start-up process exhibits two different shock structures such as FSS (Free Shock Separation) and RSS (Restricted Shock Separation). For a range of pressure ratios, hysteresis phenomenon occurs between these two separation patterns. A three-dimension compressible Navier-Stokes solver is used for the present study. One equation Spalart-Allmaras turbulence model is selected. The computed nozzle wall pressures show a good agreement with the experimental measurements. Present results have shown that present code can be used for the analysis of the transient flows in nozzle.

• Journal of Korea Game Society
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• v.13 no.3
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• pp.69-76
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• 2013

The financial value of early stage start-up has a tendency to depend more on the non-financial factors, but these are not efficiently reflected in the traditional valuation models. Therefore, most of valuation practices for early stage start-ups heavily relied on the guts of experts. To remedy this, this study suggests a model to directly reflect the non-financial factors especially for the real options approach. Actual process of valuation and the adjustment way were developed considering the characteristics of early stage start-ups in the game industry.

• Journal of ILASS-Korea
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• v.28 no.3
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• pp.150-155
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• 2023

Cold-start emissions are given great importance under the Euro-7 emission standard due to their significant impact on overall vehicle emissions. When an engine is started from a cold state, the combustion process is not yet optimized, leading to higher emissions. Hybrid vehicles, in particular, may face additional challenges, as their engine may remain inactive for extended periods, causing their catalysts to cool down and potentially become less effective in reducing emissions. In the present study, the performance of an electric heater was investigated as a means to enhance the catalyst heating during the start-up time. A simulation tool was utilized to develop a model for the gasoline exhaust aftertreatment system. The result indicates that the heater was able to increase the three-way catalyst temperature to 500℃ in 4 s using 20 kW power. In addition, the implementation of a secondary air supply resulted in reduced temperature overshoot and improved conversion efficiencies.

• East Asian Journal of Business Economics (EAJBE)
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• v.3 no.2
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• pp.21-25
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• 2015

Investment process on startup companies faces several difficulties based on the characteristics of this type of companies, such as lack of historical data, current operating losses and absence of comparable companies. In this paper we focus in a new methodology based on ordered weighted averaging (OWA) operators. OWA operators are useful instruments that enable the aggregation of information; in other words, from a data set we are able to obtain a single representative value of that set. The investment methodology presented consists on the application of OWA operators to the targeted startup companies based on the capacity of cash-flow generation and also on the planned scenario of future growth for each company. This paper shows that the methodology proposed can serve as a valuable tool, complementing the qualitative criteria (which, obviously, should not be ignored) for assessing and selecting a start-up investment.

• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.133-140
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• 2007

The current 3D CG animation pipe line, which is the production system, does not have an effective solution that all animation departments are able to start their jobs independently against other animation departments. It is generally acknowledged that we could not do animating task before the modeling and set-up task. This kind of process has caused loss of labour. We could expect lasting problems which is stopping marking animating process before the previous process done again in case of requiring editing the jobs which are modeling and set-up. We could solve these "bottleneck" situation with "master character" defined as standard, so that animate and retake the job independently against other departments. These new process could accelerate the animation pipe line system.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.318-323
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• 2015

For commercialization of fuel cell electric vehicles, one of the key objectives is to improve durability of MEA and electrocatalysts. Regarding electrocatalysts, the major issue is to reduce carbon corrosion and dissolution of Pt caused by harsh conditions, for example, SU/SD (Start-up/Shut-down). In this research, OER (Oxygen Evolution Reaction) catalyst has been developed improvement of durability. A modified polyol process is developed by controlling the pH of the solvent to synthesize the PtIr nanocatalysts on carbon supports. Each performance of the MEAs applying PtIr and Pt are equivalent because PtIrnanocatalysts have both ORR and OER activity. Breadboard test for catalyst durability in harsh conditions and high potentialsis found that the MEA applying PtIrnanocatalysts durability is improved more than the MEA applying Pt nanocatalysts.

• Journal of KIBIM
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• v.8 no.4
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• pp.23-33
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• 2018

Recently, the industry actively adopts the cutting-edge technologies of the fourth industrial revolution and uses them to enhance the productivity and service of mass-customization. The manufacturing industry is creating new processes and business models by achieving digital transformations through a lean start-up approach aimed at achieving the highest customer satisfaction with minimal resources. Although attempts are made to manufacture the building by introducing the latest technology in architecture, it is applied sporadically, not as an integrated system, in the entire phase of the architectural project. This paper analyzes the changes in the construction industry through the application of core technologies of the fourth industrial revolution. Design processes are analyzed for the digital transformation of the construction industry by case study of advanced architectural design practice. A novel design concept model 'Architectural lean startup' is proposed by combining the architectural process and the lean start up method. Through the design of the bus stop based on the architectural lean startup concept, it is confirmed that the designer repeats the 'Generate-Test-Analysis' to develop the design and generate the final result.

• Journal of Internet Computing and Services
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• v.16 no.4
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• pp.121-130
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• 2015

Technology based start-up is actively encouraged for job creation and economic performance in Korea. The Korean government has implemented a variety of policy for regulatory improvement to vitalize technology based start-up. In order to maximize the effectiveness of the policy for regulatory improvement should be actively reflect the opinions of policy beneficiaries. In this study, The importance of "The progress plan for regulation improvement about vitalization of start-up(25 contents)" published by the government was analyzed using AHP method. The object of study is the beneficiary of the policy(CEO of ICT sector). Analysis showed that the 25 contents were classified into four(1 - expectation of effect, 2 - urgency of system enforcement, 3 - complement of deficiencies, 4 - after careful consideration). This study has a academic significance to quantitative analysis about importance of policy for regulatory improvement. Also, It can be utilized when policy making and practice about technology based start-up.

• International journal of advanced smart convergence
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• v.12 no.3
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• pp.68-74
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• 2023

The food industry has been hit hard since the first outbreak of COVID-19 in 2019. However, as of April 2022, social distancing has been resolved and the restaurant industry has gradually recovered, interest in restaurant start-ups is increasing. Therefore, in this paper, 'restaurant start-up' was cited as a key keyword through social media big data analysis using TexTom, and word frequency and cone analysis were conducted for big data analysis. The keyword collection period was selected from May 1, 2022, when social distancing due to COVID-19 was lifted, to May 23, 2023, and based on this, a plan to develop chatbot services for restaurant start-ups was proposed. This paper was prepared in consideration of what to consider when starting a restaurant and a chatbot service that allows prospective restaurant founders to receive information more conveniently. Based on these analysis results, we expected to contribute to the process of developing chatbots for prospective restaurant founders in the future

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.6
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• pp.119-130
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• 2019

Although a well-established line of research has addressed the funding decision, the activities of investee startups to receive funding have been overlooked because prior research has been conduced from investor's point of view. In addition, funding does not result from one off decisions but from decision process with many stages. Moreover, the emphasis placed on specific investment criteria varies by different stages during the process. Therefore, understanding the initial funding of startups requires to analyze the strategic behaviors of startups throughout the entire funding decision process from first meeting with investors to funding success. This study investigates the initial funding process of startups, and the analysis is based on a case study of LetinAR one of the successful startups founded by students in South Korea. This study investigates how early start-ups were able to receive funding from startup's point of view, and the analysis is based on a case study of LetinAR, an augmented reality(AR) startup using Pin mirror technology. By adding "legitimacy building" stage that had not been addressed previously, we divided funding process into four stages: 1) legitimacy building, 2) familiarization, 3) screening, and 4) bargaining phase. We did not only analyze major criteria, but also strategic activities of startup at each stage. This study makes a contribution by helping us understand complicated process of funding and the successful strategic behavior of investor backed startups.