• Title/Summary/Keyword: thrust line

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The Rise of Korean Innovation Policy for Social Problem-Solving: A Policy Niche for Transition?

  • Seong, Jieun;Song, Wichin;Lim, Hongtak
    • STI Policy Review
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    • v.7 no.1
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    • pp.1-16
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    • 2016
  • Technology supply has been the main thrust of the Korean government's science & technology policy, focusing on the development and acquisition of new technology in line with the catching-up strategy of economic growth and industrial development. However, new social or societal problems have become major government policy issues, heralding new innovation policy aimed to address them. Such new policy initiatives for social problem-solving present a niche where the existing system of government innovation policy process is challenged, including such processes as goal-setting, planning, implementation, project management, and evaluation. The rigidity of the existing institution of government innovation policy, however, still shapes the content and progression of innovation policy for social problem-solving. This study reviews Korean innovation policy for social problem-solving as a policy niche, and aims to clarify its challenges and opportunities. It uses a system transition framework to explain the emergence and evolution of the innovation policy niche in Korea. The main research question is to what extent and in what aspect the existing innovation policy regime shaped innovation policy for social problem-solving. The study examines the inertia of the current paradigm of innovation policies and R&D programs, and sheds light on the search for a distinctive identity for innovation policies that tackles social problems.

Implicit/Explicit Finite Element Method for Euler Flows Inside the Optimum Nozzle (내/외재적 유한요소법을 이용한 최대추력노즐의 설계해석)

  • Yoon W. S.;Kho H.
    • Journal of computational fluids engineering
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    • v.2 no.1
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    • pp.66-72
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    • 1997
  • Optimum nozzle design exploiting the method of characteristic(M.O.C) has been in application as an efficient design methodology targeting a less weighted and short expansion nozzle. This paper treats the optimum nozzle design and the analysis of the inviscid compressible flow inside. Based on traditional Rao's method, the optimum nozzle design is coded with minor modifications for the identification of the control surface across which the mass flux should be conserved. Internal flow field is simulated numerically by M.O.C and implicit/explicit Taylor-Galerkin finite element method(F.E.M) with the aid of adaptive remeshing to capture the shock wave, hence improve the accuracy. Designed and calculated flow fields due to the separate analyses show that the mass flux predicted by optimum nozzle design with M.O.C is not conserved across the control surface and the sonic line should be located upstream of the nozzle throat. Rao's optimum nozzle design methodology exaggerates the momentum thrust and tends to overemphasize the engine performance loss.

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A Study on the Detection of the Abnormal Tool State for Neural Network in Drilling (드릴가공시 신경망에 의한 공구 이상상태 검출에 관한 연구)

  • 신형곤;김민호;김태영;김대성
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.1021-1024
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    • 2001
  • Out of all metal-cutting processes, the hole-making process is the most widely used. It is estimated to be more than 30% of the total metal-cutting process. It is therefore desirable to monitor and detect drill wear during the hole-drilling process. In this paper, the vision system of the sensing methods of drill flank wear on the basis of image processing is used to detect the wear pattern by non-contact and direct method and get the reliable wear information about drill. In image processing of acquired image, median filter is applied for noise removal. The vision flank wear area of the drill was measured. Backpropagation neural networks (BPns) were used for no-line detection of drill wear. The neural network consisted of three layers: input, hidden and output. The input vectors comprised of spindle rotational speed, feed rates, vision flank wear, thrust and torque signals. The output was the drill wear state which was either usable or failure. Drilling experiments with various spindle rotational speed and feed rates were carried out. The learning process was peformed effectively by utilizing backpropagation. The detection of the abnormal states using BPNs achieved 96.4% reliability even when the spindle rotational speed and feedrate were changed.

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A Study on Characteristics And Intrinsic Meaning of Conspicuous Kids Fashion (과시적 키즈 패션의 특성과 내적 의미 연구)

  • Kim, Hyun-Kyung;Choy, Hyon-Sook
    • Journal of the Korean Society of Costume
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    • v.66 no.7
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    • pp.1-16
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    • 2016
  • The purpose of this study was to examine the characteristics of conspicuous kids fashion and its intrinsic meaning as the popular trends of luxury product consumption expand into the area of kids' fashion. For methodologies, literature study was conducted along with empirical study. The literature study was based on various literatures and preceding studies, including books. The empirical materials used the internet photos, overseas kids fashion magazines, and free newspapers available on the basis of membership targeting the upper class. Conspicuous kids fashion refers to imported luxury kids brands, which signify higher status of the wearer due to the high prices and high quality. These brands were thrust into limelight amid the Wanna-Be Phenomenon, which resulted from the emergence of kids' fashion icons. Imported luxury brands launched the products in the form of brand line extensions. It promoted exhibition of vicarious consumption to show off the wealth and social prestige of parents. It came into prominence due to emotional consumption among kitty moms. Moreover, this study examined the intrinsic meaning of conspicuous kids fashion. The results showed components of conspicuous kids fashion, which was classified into the emphasis on outward appearance, consumption for vicarious satisfaction, inheritance of cultural capital, and network configuration.

A Study on the Presence of the Information Management Division and its Effect on the Digital Divide among Different Regions of Korea

  • Park, Woo-seok;Rhee, Cheul
    • Agribusiness and Information Management
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    • v.3 no.2
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    • pp.9-16
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    • 2011
  • With the confirmation of the Free Trade Agreement (FTA) and as cheap foreign agricultural products are beginning to be freely distributed in Korea, the government has taken a greater interest in securing the competitiveness of domestic agriculture. Accordingly, the Korean government has presented plans to advance the interests of 'small but strong farmers' and secure their competitiveness in line with the agricultural conditions in Korea. The government also announced that it will focus on leading these efforts in rural areas. The main thrust of this plan to support 'small but strong farmers' focuses onutilizing advanced peripheral technologies such as IT and BT; however, there are only a few Information Management Division centers currentlyoperating across the nation, and these are mainly in the IT-related divisions of the Agricultural Research and Extension Services and Agricultural Technology Centers. Therefore, in this study, we used the responses from a survey of farmers to identify regional differences in informatization levels and the digital divide among 'small but strong farmers' according to the presence or absence of an Information Management Division center. As a result, we found that the 'small but strong farmers' in regions with an active Information Management Division center received more IT services and had a higher level of informatization. Thus, to increase the use of IT-related peripheral technology by these 'small but strong farmers', it is important to maintain or increase the number of Information Management Division centers.

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Numerical prediction analysis of propeller exciting force for hull-propeller-rudder system in oblique flow

  • Sun, Shuai;Li, Liang;Wang, Chao;Zhang, Hongyu
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.1
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    • pp.69-84
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    • 2018
  • In order to analyze the characteristics of propeller exciting force, the hybrid grid is adopted and the numerical prediction of KCS ship model is performed for hull-propeller-rudder system by Reynolds-Averaged Navier Stokes (RANS) method and volume of fluid (VOF) model. Firstly, the numerical simulation of hydrodynamics for bare hull at oblique state is carried out. The results show that with the increasing of the drift angle, the coefficients of resistance, side force and yaw moment are constantly increasing, and the bigger the drift angle, the worse the overall uniformity of propeller disk. Then, propeller bearing force for hull-propeller-rudder system in oblique flow is calculated. It is found that the propeller thrust and torque fluctuation coefficient peak in drift angle are greater than that in straight line navigation, and the negative drift angle is greater than the positive. The fluctuation peak variation law of coefficient of side force and bending moment are different due to various causes.

Coupled dynamic responses of a semisubmersible under the irregular wave and turbulent wind

  • Dey, Swarnadip;Saha, Kaushik;Acharya, Pooja;Roy, Shovan;Banik, Atul K.
    • Ocean Systems Engineering
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    • v.8 no.4
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    • pp.441-459
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    • 2018
  • A coupled dynamic analysis of a semisubmersible-type FOWT has been carried out in time domain under the combined action of irregular wave and turbulent wind represented respectively by JONSWAP spectrum and Kaimal spectrum. To account for the turbine-floater motion coupling in a more realistic way, the wind turbulence has been incorporated into the calculation of aerodynamic loads. The platform model was referred from the DeepCwind project and the turbine considered here was the NREL 5MW Baseline. To account for the operationality of the turbine, two different environmental conditions (operational and survival) have been considered and the aerodynamic effect of turbine-rotation on actual responses of the FOWT has been studied. Higher mean offsets in surge and pitch responses were obtained under the operational condition as compared to the survival condition. The mooring line tensions were also observed to be sensitive to the rotation of turbine due to the turbulence of wind and overestimated responses were found when the constant wind was considered in the analysis. Additionally, a special analysis case of sudden shutdown of the turbine has also been considered to study the swift modification of responses and tension in the mooring cables.

Development History of Neotectonic Fault Zone in the Singye-ri Valley, Oedong-eup, Gyeongju, Korea (경주시 외동읍 신계리 계곡에 발달하는 신기 단층대 발달사)

  • Kang, Ji-Hoon;Son, Moon;Ryoo, Chung-Ryul
    • Korean Journal of Mineralogy and Petrology
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    • v.33 no.4
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    • pp.349-359
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    • 2020
  • The Ulsan Fault Zone (UFZ) of NNW trend is developed in the Gyeongsang Basin, the southeastern part of the Korean Peninsula, and the Quaternary faults have been found around the UFZ. The faults generally thrust the Bulguksa igneous rocks of Late Cretaceous-Early Tertiary upon the Quaternary deposits or are developed within the Quaternary deposits. They mainly show the reverse-slip sense of top-to-the west movement. The lines connecting the their outcrop sites show a zigzag-form which is similar to the orientation of their fault surfaces which show the various trends, like (W)NW, N-S, (E)NE, ENE trends. The E-W trending dextral strike(-slip) fault is found in the Quaternary deposits of the Singye-ri valley. It cuts the N-S trending reverse fault and are cut by the N-S trending thrust fault again. Two types of at least two times of Quaternary tectonic movements related to the formation of neotectonic fault zone in the Singye-ri valley are considered from such the geometric and kinematic characteristics of Quaternary faults. One is the reverse faulting of N-S trend by the E-W directed 1st compression and associated the strike-slip tear faulting of E-W trend, and then the thrust faulting of N-S trend by the E-W directed 2nd compression. The other is the reverse faulting of N-S trend, and then the dextral strike-slip faulting of E-W trend by the NW-SE directed compression, and then the thrust faulting of N-S trend. In this paper is suggested the development history of Singye-ri neotectonic fault zone on the basis of the various orientations of Quaternary fault surfaces around the UFZ, and the zigzag-form connecting line of their outcrop sites, and the compressive arc-shaped lineaments which convex to the west reported recently in the Yangsan Fault Zone.

Experimental Study on Aerodynamic Performance and Wake Characteristics of the Small Ducted Fan for VTOL UAV (수직 이착륙 무인기용 소형 덕티드팬의 공력성능 및 후류특성에 관한 실험적 연구)

  • Shin, Soo-Hee;Lee, Seung-Hun;Kim, Yang-Won;Cho, Tae-Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.1
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    • pp.1-12
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    • 2022
  • Wind tunnel test for a small scale electric ducted fan with a 104mm diameter was conducted to analyze the aerodynamic characteristics when it was used as a propulsion system of tilt-propeller UAV. Experimental conditions were derived from flight conditions of a sub-scaled OPPAV. Forces and moments of the ducted fan model were measured by a 6-axis balance and 3-dimensional wake vectors which could induce an aerodynamic influence in the vehicle were measured by 5-hole probes. Thrust and torque on hover and cruise conditions were measured and analyzed to drive out the operating conditions when it was applied in the sub-scaled OPPAV. On transition conditions, thrust keep its value with tilt angle variation below 40° and increase after that. But, sideforce increase constantly until 75°. The maximum axial velocity in the wake on hover and cruise conditions was around 60m/s and tangential velocity was around 12m/s. The position of the maximum axial velocity and vortex center move off the fan rotation center line as the tilt angle increases.

Development of a Structural Safety Evaluation System for Stone Voussoir Arch Bridges (석조 홍예아치교의 구조적 안정성 평가시스템 개발)

  • Kim, Nam-Hee;Koh, Hyun-Moo;Hong, Sung-Gul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.1
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    • pp.15-23
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    • 2009
  • Masonry structures that are very strong in compression fail due to the instability of structural shape of geometry rather than the material stress limit. Considering such structural behavior, the use of the limit theorem that focuses on structural collapse mechanisms is more appropriate for the evaluation of the structural safety of stone voussoir arch bridges. This paper is to investigate structural performance of the stone arch bridges constructed using dry construction method in Korea based on the limit theorem and to exploit the result to develop a system for an structural safety margin. It is expected that this study will help us understand structural behavior of stone voussoir arch bridges in Korea. Also, it will provide a guideline to make engineering decision from the viewpoint of the maintenance of cultural heritages.