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Nano-particles emission characteristics of GDI vehicles using Engine Exhaust Particle Sizer (Engine Exhaust Particle Sizer를 통한 GDI 자동차에서 발생하는 나노미세입자 배출특성 분석)

  • Jang, Jihwan;Lee, Jongtae;Kim, Kijoon;Kim, Jeongsoo;Park, Sungwook
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.95-96
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    • 2014
  • In this study, the nano-particle emitted from Gasoline Direct Injection(GDI) vehicles was measured using the Engine Exhaust Particle Sizer(EEPS) on a chassis dynamometer. In addition, driving mode were divided into cold start mode(CVS-75, NEDC) and hot start mode(NIER-6, NIER-9) to evaluated the characteristics in the various operating conditions. The Particle Number(PN) concentration was analyzed for various driving patterns, i.e., acceleration, deceleration, idling, cruising and the phases of mode. In a result, Total concentration of PN for size was concentrated from 50 to 100 nm and acceleration represents the highest concentration among the driving pattern. It is believed that the increases quantity of fuel, and mixture will be richer than other patterns.

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A Study on the Development of an Electronic Control System for Optimal Start and Idle Speed Control in Gasoline Engines (기솔린 기관에서 최적의 시동 및 공회전 속도제어를 위한 전자 제어장치 개발에 관한 연구)

  • 김태훈
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.5
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    • pp.1148-1160
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    • 2001
  • An electronic control system of the automobile engine for optimal start and idle speed control has been developed. This system employs the microcoputer-based electronic control unit and crank angle sensor for precise control on fuel injection, ignition timing, and idle speed more quickly and accurately at the start and idling. Consequently, the number of misfire can be reduced during been affected by air flow rate, idle quality(roughness), spark timing, fuel injection, water temperature, and load, Thus, this electronic control system strivers to reach the optimal idle operating point, defined the lowest idle speed(fuel economy) and idle quality(roughness), under any engine operating conditions.

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Effects of Initial Nucleation Condition at the Start Block on the Grain Size and Growth Direction in Directionally Solidified CM247LC Superalloy (CM247LC 초내열합금에서 일방향응고 스타트 블록의 초기 핵생성 조건에 따른 결정립 성장)

  • Yoon, Hye-Young;Lee, Je-Hyun;Jung, Hyeong-Min;Seo, Seong-Moon;Jo, Chang-Young;Gwon, Seok-Hwan;Chang, Byeong-Moon
    • Korean Journal of Metals and Materials
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    • v.49 no.1
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    • pp.58-63
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    • 2011
  • The grain size and growth direction of a directionally solidified turbine blade were evaluated by the initial nucleation condition at the start block of directional solidification. The initial nucleation condition was controlled by inserting a Ni foil on the directional solidification plate of the directional solidification furnace. Fine grains with good orientation were obtained in the faster cooling condition at the start block. The nucleus number was compared with the cooling rate of the start block by electron back scattered diffraction (EBSD). DSC (differential scanning calorimeter) analysis was performed to compare the melting point and undercooling for nucleation of the coarse nuclei and fine nuclei of the start block. The faster cooling condition at the start block showed more undercooling for nucleation and smaller size of nuclei which resulted in a fine grain with good orientation in the directional turbine blade.

Design and Implementation of a Web System Providing Optimal Travel Routes (여행지 최적 경로를 제공하는 웹 시스템의 설계와 구현)

  • Yim, Jae-Geol;Lee, Kang-Jai
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.5
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    • pp.19-27
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    • 2007
  • We have implemented a WWW homepage which finds an optimal route for users. There already exist many web sites which provide the optimal route when a start and a destination cities are given. However, none of them can find the optimal route when a number of cities to be visited. The problem of finding the optimal route starting at a given start city and visiting through all the given intermediate cities and finally returning to the start city is called Travelling Sales Person(TSP) problem. TSP is a well known exponential time complexity problem. We have implemented an artificial intelligent search algorithm for TSP on our homepage. The main feature of our algorithm is that the destination may not be the same as the start city whereas all of the existing heuristic algorithms for TSP assume that the start and the destination cities are the same. The web page asks a user to select all the cities he or she wants to visit(including start and destination city), then it finds a sequence of the cities such that the user would travel minimum distance if he or she visits the cities in the order of the sequence. This paper presents algorithms used in the homepage.

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Start-up Circulation Structure Design based on Corporate Ecosystem and Its Case Studies (기업생태계에 기초한 창업순환 구조설계 및 사례 연구)

  • Yoo, Soonduck
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.15 no.2
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    • pp.245-254
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    • 2015
  • The purpose of this research is to study the cyclic structure of startup ecosystem and draw the necessary conditions for maintaining it to successfully induce the activation entrepreneurship. Therefore, we design start-up cycle structure based on the enterprise ecosystem to verify this, we discussed the Tech City in the United Kingdom and Silicon Valley in USA. Required factors for running the start-up cycle structure is summarized as follows. First, the shared platform is provided to form between components in accordance with the object, second, this can be made based on the excellent human resources, third, a number of consumer groups such as venture capitals and angels that revenue from the virtuous circle should be formed, fourth, get the other regional networks and associated, fifth to make it easy to start-ups through government and institutional support and finally, a stand-alone producers(startups) should be fostering entrepreneurship.

A Study on Investment Determinants by the Types of Start-up Accelerators (스타트업 액셀러레이터의 민간·공공 유형별 투자결정요인에 대한 연구)

  • Heo, Ga El;Chung, Seung Wha;Kim, Ji Yeon
    • Korean small business review
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    • v.43 no.4
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    • pp.173-209
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    • 2021
  • Start-up accelerators are a new type of investor that provide mentoring, education and seed capital to start-ups for a fixed duration and receive a certain stake in them in return. They help start-ups achieve successful commercialization. With increase in performance visibility, the number of private and public sector accelerators rose across domestic and international markets. Private sector accelerators are established and operated by private entities while public sector accelerators are established and operated by the government. Both play complementary roles that are becoming increasingly important to start-ups. Therefore, this study aims to examine the differences in major operational goals and investment determinants between private and public sectors and to understand their implications. The results show that the private sector prioritizes profit generation through the investment, while the public sector aims to contribute to the development of high-growth start-ups, and create region-specific and technology-specific start-up ecosystems. Additionally, both groups consider customer needs the most important determinant. Public groups are more conservative in investments and tend to place importance on objective indicators such as patents, partners, mentors, and co-founders. Conversely, private groups value the capabilities of founders and their ease of collaboration with accelerators. These findings can help start-ups get support from public or private accelerators more easily. It will also help public and private accelerators refine the criteria for selecting start-ups.

PIV Measurements of Hull Wake behind a Container Ship Model with Varying Loading Condition and Reynolds number (선박 모형의 하중 (loading)조건 및 Reynolds 수의 변화에 따른 선미 반류의 PIV 속도장 측정)

  • Lee Jung-Yeop;Paik Bu-Geun;Lee Sang-Joon
    • 한국가시화정보학회:학술대회논문집
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    • 2005.12a
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    • pp.54-57
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    • 2005
  • Flow characteristics of hull wake behind a container ship model were investigated experimentally with varying loading condition and Reynolds number. Large-scale bilge vortices of nearly the same strength are formed in the near-wake region. They are symmetric and counter-rotating with respect to the wake centerline for all loading conditions tested. With going downstream for both design and ballast loading conditions, the strength of the bilge vortices decreases and the wake region expands due to diffusion and viscous dissipation. Under the design loading condition, the bilge vortices start to appear at St=0.363 transverse plane above the propeller-boss. For the ballast loading condition, however, the bilge vortices start to appear at St=0.591 below the propeller-boss. They move upward as the hull wake goes downstream and Reynolds number increases. These wake characteristics, under the ballast loading condition, may weaken the propulsion and cavitation performances of the propeller, which are usually optimized for the design loading condition.

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Three Hypothesis Tests for Determinants of Business Start-up (산업별 창업 결정요인의 세 가지 가설 검증, 2008-2014년)

  • Lee, Changkeun
    • Journal of the Korean Regional Science Association
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    • v.33 no.1
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    • pp.17-27
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    • 2017
  • The purpose of this study is to analyze the determinants of start-ups by industry based on the theoretical background of entrepreneurship. For this purpose, regional industrial structure and local labor market structure are considered in order to focus on regional factors in addition to economic factors, income factors, and technological innovation factors. As an analyzed result, three theories of entrepreneurship generally agree with the determinants of industry - specific entrepreneurship. During the economic recession, the number of start-ups has increased. The intra-regional consumption and the local government expenditure per capita have also positive effects on the start-up. The incubation center has a positive effect on the start - up in the manufacturing sector. Therefore, the academic-industrial leading various incubation facilities should be activated in addition to the central or local government leading incubation centers, which is a part of the policy to support start-ups of central and local governments. In addition, population growth is a very important factor in terms of potential demand creation, and the characteristics of regional industrial structure and the effect of human capital within the region differ by industry. In the case of the manufacturing industry, the accumulation effect positively influences the start-up of the industry. In other service industries, the human capital variable had the greatest effect on the start-up when all other conditions are constant.

Evaluation of a Parent Training Program for Promoting Filipino Young Children's Number Sense with Number Card Games

  • Cheung, Sum Kwing;McBride-Chang, Catherine
    • Child Studies in Asia-Pacific Contexts
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    • v.5 no.1
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    • pp.39-49
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    • 2015
  • Not all parents are skilled in scaffolding their young children's numeracy learning. The present study investigated the effectiveness of a parent training program in promoting Filipino young children's number sense via card game playing at home. Participants were 161 young children and their parents; families were of a relatively low socioeconomic status. During the 10-week intervention period, parents in the experimental group received training on how to use number game cards to help their children acquire various numeracy concepts; parents in the control group received no special instructions. Children in the experimental group showed greater improvements in their performance on six number sense tasks (namely numeral identification, object counting, rote counting, missing number, numerical magnitude comparison, and addition) over the intervention period than did children in the control group. Findings of the present study suggest that providing simple training to parents on strategies for fostering their young children's number sense at home is important for giving children a good early start in basic number knowledge.

Republic of Korea Entrepreneurship Ecosystem Status and Recognition Research: Focusing on Entrepreneurs, Entrepreneurs Preliminary, Student Centered Comparative Analysis on the Status and Recognition (대한민국 창업생태계 현황 및 인식 연구: 창업가, 예비창업가, 학생을 중심으로 현황 및 인식 비교 분석)

  • Kim, Sung Hoon;Nam, Jung min
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.11 no.6
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    • pp.175-183
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    • 2016
  • The government set up "national happiness, the hope of a new era of national vision under' job center of the creative economy" to achieve by national goals in the first and figure achieved through the establishment of new growth engines of the youth unemployment problem solve and national level there are a number of business start-up support. September 8, 2015 announced the Government's look at the '2016 Year of the budget, the government for new growth engines greatly promoted the venture entrepreneurship ecosystem revitalization and research and development (R & D) the business for enhanced performance in 2017. According to the direction of this study is to evaluate the current creative economy business incubator at the comparison whether the correct orientation mainly entrepreneurs, entrepreneurs preliminary recognition of student entrepreneurship ecosystem. Entrepreneurs 113 people in that way, 71 people pre-entrepreneurs, students 60, workers were founding agencies conducted an online survey of 47 people, 16 people Investors, 50 public and 11 additional persons including a total of 368 people. This study is in line with the orientation of these entrepreneurs to create economic status and recognition of the Republic of Korea entrepreneurship ecosystem, pre- entrepreneurs, students will examine the comparative analysis around. Analysis, social perception of entrepreneurship is somewhat higher than it was confirmed that the negative response of 32.2% to 36.3% of positive response. Social awareness of entrepreneurs showed a 2-fold higher response rate than the negative of response of 17.1% to 41.7% responding that positive recognition for the current start-up environment is bad, the response is good response to higher response rate than 23.5% to 41.1% It showed. The percentage of responses that better respect the entrepreneurship environment of the future Republic of Korea showed a higher response rate than the rate of 23% in response to deteriorate to 41.2%, with 52.9% awareness is the percentage that responded that the bad part about the ruthless Korea's entrepreneurship environment in China good part as response rate approximately three times greater than the 17.7% showed high response rates. Social awareness of entrepreneurs experience the presence of the founding start-up experience was confirmed that the more negative the number increases, the more the contrary the number of start-up experience increased awareness of the current and future environment of entrepreneurship was identified as a positive entrepreneurship environment. Also recognized was confirmed to change the parent of the more positive changes in the start-up of entrepreneurs doctor also positive about entrepreneurship, start-up entrepreneurs start with a doctor's motivation for founding non-economic reasons than for economic reasons has confirmed Higher. This study showed the overall level overview analysis of the status and recognition of the Republic of Korea entrepreneurship ecosystem. Future studies need to be a proposal for an existing previous studies for more precise direction to go forth to analyze the entrepreneurship ecosystem with a focus on problems and improvement of the Republic of Korea entrepreneurship ecosystem.

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