• 한국분무공학회지
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• 제19권1호
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• pp.40-46
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• 2014

Recently rise in oil prices feet the burden on not only diesel vehicle driver but also LPG vehicle driver, and get interested in various way to reduce fuel costs. In this study discuss on exhaust emissions characteristics on driving cycle mode and ignition advance condition change of CNG/LPLI Bi-Fuel vehicle. Experimental test was performed by changing the conditions of fuel (LPG/CNG), spark advance (Base, $10^{\circ}CA$, $15^{\circ}CA$), and driving mode (FTP-75, HWFET, and NEDC). In case of CO emission, in the order of CNG Base, CNG S/A10, S/A15 condition are average reduced -21%, -35%, -29% respectively compared to LPG fuel. The active emission reduction from the initial engine start, spark retard is likely to be beneficial in catalyst warm-up and improve combustion stability rather than spark advance.

• 전기학회논문지
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• 제65권6호
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• pp.979-986
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• 2016

At present, electric power industry around the world are being gradually changed to a new paradigm, such as electrical energy storage system, the wireless power transmission. Demand for ESS, the core technology of the new paradigm, has been growing worldwide. However, it is essential to estimate the optimal capacity of ESS facilities for frequency regulation because the benefit would be saturated in accordance with the investment moment and the increase of total invested capacity of ESS facilities. Hence, in this paper, the annual optimal mathematical investment model is proposed to estimate the optimal capacity and to establish investment plan of ESS facility for frequency regulation. The optimal mathematical investment model is newly established for each season, because the construction period is short and the operation effect for the load by seasons is different unlike previous the mathematical investment model. Additionally, the marginal operating cost is found by new mathematical operation model considering no-load cost and start-up cost as step functions improving the previous mathematical operation model. ESS optimal capacity is established by use value in use iterative methods. In this case, ESS facilities cost is used in terms of the value of the beginning of the year.

• 한국분무공학회지
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• 제22권4호
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• pp.185-189
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• 2017

In Korea, sales of passenger cars using diesel and LPG fuels were continuously increased in recent years. From now on 2030, the registrated vehicles will close in about twenty five million in Korea. From these reason, Investigation on the comparison of exhaust emission characteristics of passenger cars using LPG and Diesel fuel in variation of driving mode and ambient conditions were conducted in this study. Exhaust emission characteristics of test vehicles were measured and analyzed by using chassis dynamometer and emission analyzer. Also, test vehicles were selected on the diesel vehicle with 1.7L engine and LPG vehicle with 2.0L engine. In order to study on emission characteristics according to driving cycles, CVS-75, NEDC, US06, SC03, Cold-FTP and HWFET were applied and the test conditions were set up the cases of A/C on and hot start. From these results, it is revealed that the NOx emission of diesel vehicle was higher than that of LPG vehicle and the case of CO emission shows the opposite patterns. In the HC emission, the emission increasing patterns not showed but the NOx emission of diesel vehicle and CO emission of LPG vehicle were showed the variation patterns according to the various driving modes.

• 대한안전경영과학회지
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• 제17권4호
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• pp.343-352
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• 2015

This study analyzes the business performance of research and development(R&D) and especially studies the effect of technology management activity and technology innovation competency on commercialization performance. According to previous studies, the technology management activity can be composed of technological innovativeness, analysis of market, R&D method, and appropriateness for commercialization plan. Also, the technology innovation can be divided into patent, R&D manpower, R&D investment ratio, production capability, and marketing capability. On the result of the analysis, all the components of technology management activity are positively related with commercialization performance. In case of technology innovation competency, however, only production and marketing capabilities have influence on the business performance. Especially, marketing capability controls the effect of technology management activities on the commercialization performance. Consequently, technology management is very important activity for SMEs to succeed commercialization and SMEs should collaborate with production and marketing departments from the early stage of R&D.

• 한국조명전기설비학회지:조명전기설비
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• 제6권2호
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• pp.56-61
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• 1992

유도 전동기의 일정자속 벡터제어에서 유도전동기의 속도를 별도의 속도검출장치가 없이, 전동기의 속도를 1차측 전압과 전류 및 전동기정수에 의하여 추정하는 방법을 제시하고 전류추종형 PWM인 버터에 의하여 구동 시스템을 구성하였다. 모든 연산 및 제어회로를 마이크로프로세서에 의하여 보다 간단하게 실현시켜 유도전동기의 가변속 구동특성을 컴퓨터 시뮬레이션과 실험에 의하여 조사하였다. 속도검출장치를 이용한 경우와 연산회로에 의하여 계산된 경우의 입력 전류파형상의 차이를 조사한 결과 미소한 리플성분을 제외하고는 잘 일치하였으며, 기동 및 가감속시의 속도추종특성도 시뮬레이션의 결과와 함게 양호하게 얻어졌다.

• 한국시스템다이내믹스연구
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• 제6권1호
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• pp.125-145
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• 2005

The Sihwaho Project got off to a bad start, which led to a series of mishaps and an imbalance of the whole project. The purpose of this study is to select the case of Sihwaho as a research subject, clean up the contamination caused by the ill planned project, develop suitable measures to stabilize the lake environment, and find the implications of similar development projects. For this, the authorshave conducted three simulations after studying the structural reasons for the failure of the Sihwaho Policy by identifying cause and effect relationships, pre-testing a number of policy measures for the current lake project, and presenting measures for solving the contamination problem at the lake. The simulations have shown us that filling the lake with seawater is inadequate to solve the problem and that we also have to make efforts to reduce the volume of wastes to the lake as well. The authorshave also analyzed the degree of difference between the simulation and survey results for scenario 1, in which we have studied how much seawater can reduce the contamination of the Sihwaho Lake without the effort to reduce the volume of wastes into the lake. The survey showed that most citizens and employees of the Ministry of Environment did not think it would be serious as the simulation results pointed out, and the employees of the Ministry of Environment were more optimistic about the situation than the public.

• 전기학회논문지
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• 제63권1호
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• pp.18-26
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• 2014

A microgrid can play a significant role for enlargement of renewable energy sources and emission reduction because it is a network of small, distributed electrical power generators operated as a collective unit. In this paper, an application of optimization method to economical operation of a microgrid is studied. The microgrid to be studied here is composed of distributed generation system(DGS), battery systems and loads. The distributed generation systems include combined heat and power(CHP) and small generators such as diesel generators and the renewable energy generators such as photovoltaic(PV) systems, wind power systems. Both of thermal loads and electrical loads are included here as loads. Also the emissions trading scheme to be applied in near future, the cost of unit start-up and the operational characteristics of battery systems are considered as well as the probabilistic characteristics of the renewable energy generation and load. A mathematical equation for optimal operation of this system is modeled based on the mixed integer programming. It is shown that this optimization methodology can be effectively used for economical operation of a microgrid by the case studies.

• Wind and Structures
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• 제28권6호
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• pp.389-404
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• 2019

In coastal regions, it is common to witness significant damages on low-rise buildings caused by hurricanes and other extreme wind events. These damages start at high pressure zones or weak building components, and then cascade to other building parts. The state-of-the-art in experimental and numerical aerodynamic load evaluation is to assume buildings with intact envelopes where wind acts only on the external walls and correct for internal pressure through separate aerodynamic studies. This approach fails to explain the effect of openings on (i) the external pressure, (ii) internal partition walls; and (iii) the load sharing between internal and external walls. During extreme events, non-structural components (e.g., windows, doors or rooftiles) could fail allowing the wind flow to enter the building, which can subject the internal walls to lateral loads that potentially can exceed their load capacities. Internal walls are typically designed for lower capacities compared to external walls. In the present work, an anticipated damage development scenario is modelled for a four-story building with a stepped gable roof. LES is used to examine the change in the internal and external wind flows for different level of assumed damages (starting from an intact building up to a case with failure in most windows and doors are observed). This study demonstrates that damages in non-structural components can increase the wind risk on the structural elements due to changes in the loading patterns. It also highlights the load sharing mechanisms in low rise buildings.

• 한국경제지리학회지
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• 제23권4호
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• pp.395-407
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• 2020

이 논문은 지역산업 구조변화 동인으로 기업가적 정신의 중요성이 대두되고 있는 가운데 지방 행정수장인 정치인과 신생 중소기업 경영자의 기업가적 활동이 지역산업에 미친 영향을 파악하는데 목적을 두었다. 특히, 관련 연구가 아직 미미한 상황에서 정치인과 경영인이라는 각기 다른 유형의 기업가적 정신과 이에 대한 동기부여를 분석함으로써 부족한 실증연구의 지식격차를 좁히는데 도움을 주었다. 정치인의 기업가적 정신이 전라북도 탄소산업 육성에 미친 영향과 사양화에 접어든 섬유산업에 뛰어든 신생업체 경영인의 기업가정신을 통한 혁신적 성장사례를 통해 지금껏 지역산업 정책을 수립하는 과정에서 상대적으로 크게 고려되지 않았던 기업가적 정신의 필요성을 발견하였고, 이를 통해 정책적 함의를 도출하였다.

• 디지털산업정보학회논문지
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• 제20권1호
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• pp.149-160
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• 2024

This paper was conducted to improve understanding of how the start-up process affects the local community and how young entrepreneurs build and grow their businesses in the process through analysis of young people who started businesses in the region. The research method was conducted through in-depth interviews with 10 young entrepreneurs who started businesses in the western Gyeongsangnam-do region, where population decline is prominent, and the collected data was analyzed through a grounded theory approach to derive common and meaningful themes between each case. proceeded. As a result of the study, insights were derived about the background of entrepreneurs settling in the region, the motivation for starting a business using local resources, the impact of government and local government support, business strategies for sustainable growth, and the entrepreneurs' personal performance. Through this analysis, we hope to provide important insights into the positive impact local entrepreneurship has on the community and how young entrepreneurs contribute to local development.