• 한국문헌정보학회지
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• 제57권2호
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• pp.241-269
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• 2023

본 연구는 수혜자의 관점에서 공공성을 측정할 수 있는 척도를 개발하고, 도서관 이용 경험, 지역 주민의 개인적 특성, 도서관 서비스 유형에 따라 공공성에 대한 인식 차이를 측정하였다. 이를 위해 공공성 관련 특성들을 문헌 고찰을 통해 분석하여 공공성 측정 지표로 통합하였고, 서울시 5개 자치구의 지역 공공도서관 15곳을 대상으로 설문조사를 실시하였다. 그 결과, 도서관 공공성은 '참여반응성, 절차공정성, 상황평등성'의 3가지 요인으로 구성되며, 각 요인은 도서관과 지역 주민 간 상호작용 속에 형성되는 서로 다른 측면을 보여준다는 점을 발견하였다. 이를 바탕으로 도서관 이용 경험과 서비스 기간, 지역 주민의 직업 환경과 지역활동경험, 도서관 서비스 유형 등에 따라 어떠한 공공성의 측면을 강화해 나가야 하는지를 제시하였다. 공공성을 강화할 수 있는 서비스 경험이 제공될 때, 보다 많은 지역 주민이 혜택을 누릴 수 있으며, 이로써 도서관의 존재가치를 증명할 수 있을 것이다.

• 대한기계학회논문집B
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• 제22권6호
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• pp.771-787
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• 1998

A Navier-Stokes code with a modified low Reynolds number k-.epsilon. turbulence model was used to study the unsteady transitional boundary layer flow due to rotor-stator interaction. The modification, proposed by Launder, to improve prediction of stagnation flows was incorporated to the low Reynolds number k-.epsilon. turbulence model by Fan-Lakshminarayana-Barnett. Numerical solution is shown to capture well the calmed laminar flow as well as the wake induced transitional strip due to rotor-stator interaction and shows improvement, in terms of onset of transition and its length, over previous Euler/boundary layer solution. The turbulent kinetic energy shows local maximum along the upstream rotor wake in the wake induced transitional strip and this characteristics is observed untill the end of transition. The wake induced strip also shown apparent even in the laminar sublayer as the upstream rotor wake penetrates inside the boundary layer.

• 한국항공우주학회지
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• 제34권12호
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• pp.18-24
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• 2006

슬롯과 다공판을 이용한 충격파와 난류 경계층 간섭유동의 피동제어에 관한 연구가 수행되었다. 슬롯의 다양한 형상 변화가 간섭유동에 미치는 영향이 관찰되었으며, 이를 위하여 간섭유동 후방에서 피토/벽압력 분포 및 쉴리렌, 유맥선, 오일막 간섭 줄무늬 형상과 같은 유동가시화 결과 등이 얻어졌다. 유동방향의 슬롯의 경우 간섭유동 후방에서 제어되지 않은 경우와 비교하여 보다 높은 피토압력이 국소적으로 관찰되었으나, 폭방향 슬롯제어는 전체적으로 제어되지 않은 경우에 비하여 피토압력 크기에서 큰 장점을 보이지 않았다.

• Wind and Structures
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• 제9권2호
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• pp.95-108
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• 2006

Wind turbines are highly complex structures for numerical flow simulation. They normally comprise of a turbine mounted on a tower thus the movement of the turbine blades and the blade/tower interaction must be captured. In addition the ground effect should also be included. There are many more important features of wind turbines and it is difficult to include all of them. A simplified set of features is chosen here for both the turbine and the tower to show how the method can begin to identify the main points connected with wind turbine wake generation and tip vortex tower interaction. An approach to modelling the rotating blades of a turbine is proposed here. The model uses point forces based on blade element theory to model the blades and takes into account their time dependent motion. This means that local instantaneous velocities can be used as a basis for the blade element theory. The model is incorporated into a large eddy simulation code and, although many important features are left out of the model, the velocity/power performance relation is generally of the correct order of magnitude. Suggested improvements to the method are discussed.

• Earthquakes and Structures
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• 제4권5호
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• pp.557-585
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• 2013

The recent huge earthquake ground motion records in Japan result in the reconsideration of seismic design forces for nuclear power stations from the view point of seismological research. In addition, the seismic design force should be defined also from the view point of structural engineering. In this paper it is shown that one of the occurrence mechanisms of such large acceleration in recent seismic records (recorded in or near massive structures and not free-field ground motions) is due to the interaction between a massive building and its surrounding soil which induces amplification of local mode in the surface soil. Furthermore on-site investigation after earthquakes in the nuclear power stations reveals some damages of soil around the building (cracks, settlement and sand boiling). The influence of plastic behavior of soil is investigated in the context of interaction between the structure and the surrounding soil. Moreover the amplification property of the surface soil is investigated from the seismic records of the Suruga-gulf earthquake in 2009 and the 2011 off the Pacific coast of Tohoku earthquake in 2011. Two methods are introduced for the analysis of the non-stationary process of ground motions. It is shown that the non-stationary Fourier spectra can detect the temporal change of frequency contents of ground motions and the displacement profile integrated from its acceleration profile is useful to evaluate the seismic behavior of the building and the surrounding soil.

• 한국전산유체공학회지
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• 제14권3호
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• pp.76-85
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• 2009

The shock wave is deformed and the vortex is elongated simultaneously during the shock-vortex interaction. More precisely, the shock wave is deformed to a S-shape, consisting of a leading shock and a lagging shock by which the corresponding local vortex flows are accelerated and decelerated, respectively: the vortex flow swept by the leading shock is locally expanded and the one behind the lagging shock is locally compressed. As the leading shock escapes the vortex in the order of microseconds, the expanded flow region is quickly changed to a compression region due to the implosion effect. An induced shock is developed here and propagated against the vortex flow. This happens for a strong vortex because the tangential flow velocity of the vortex core is high enough to make the induced-shock wave speed supersonic relative to the vortex flow. For a weak shock, the vortex is basically subsonic and the induced shock wave is absent. For a vortex of intermediate strength, an induced shock wave is developed in the supersonic region but dissipated prematurely in the subsonic region. We have expounded these three shock-vortex interaction patterns that depend on the vortex flow regime using a third-order ENO method and numerical shadowgraphs.

• 한국안전학회지
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• 제25권2호
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• pp.12-17
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• 2010

Numerical simulations were performed for the prediction of the flame structure during the interaction between hydrogen and hydrocarbon flames. A counterflow flow geometry was introduced to establish the interacting two flames. Methane was used as a representative hydrocarbon fuel in this study. A well-known numerical code for the counterflow flame, OPPDIF, was used for the simulations. The detailed chemistry was adopted to predict the flame structure reasonably. The interaction of two one-dimensional premixed flames established in counterflow burner was investigated with the global strain rate and velocity ratio. It was found that the maximum temperature located near the methane flame surface while the heat release rate of methane was lower than hydrogen flame. The flame thickness become narrow with increasing the velocity ratio while the global strain rate was fixed. The local strain rate and heat release rate at the methane flame surface were correlated with the global strain rate, while those at the hydrogen flame were not correlated with the global strain rate. However, the maximum temperature of the interacting flames was correlated with the global strain rate.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.6097-6120
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• 2019

Online consumer reviews (OCRs) provide product information and recommendations especially pictures in reviews depict the true information about the product. This study investigates the influence of pictured reviews on online seller (for a particular product of a seller) rating with moderating effect of price, brand type (foreign vs local), goods type (experience vs search), and brand familiarity. Multiple robust linear regression analysis with moderation interaction and quadratic effect used to explain the relationship of the explanatory variables with the criterion variable. We collected cross-sectional data from the two most renowned Chinese online shopping platforms (B2C) of total 15,621 product links. Results show that higher number of reviews with a low ratio of picture reviews response negative effect on rating, whereas the lower number of reviews with a high ratio of picture reviews response positive effect on the rating. In overall picture in the reviews improve the online seller product rating. For the moderation effect, results show that price and brand familiarity have a positive interaction effect on the relation of pictured reviews and rating whereas experience goods have less negative effect comparing search goods. Finally, local brand has less negative interaction effect comparing foreign brand to pictured reviews and rating.

• Smart Structures and Systems
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• 제33권2호
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• pp.145-163
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• 2024

The evaluation of dynamic characteristics of bridges under operational traffic loads is a crucial aspect of bridge structural health monitoring. In the vehicle-bridge interaction (VBI) system, the vibration responses of bridge exhibit time-varying characteristics. To address this issue, an accurate time-frequency analysis method that combines the autoregressive power spectrum based empirical wavelet transform (AR-EWT) and local maximum synchrosqueezing transform (LMSST) is proposed to identify the time-varying instantaneous frequencies (IFs) of the bridge in the VBI system. The AR-EWT method decomposes the vibration response of the bridge into mono-component signals. Then, LMSST is employed to identify the IFs of each mono-component signal. The AR-EWT combined with the LMSST method (AR-EWT+LMSST) can resolve the problem that LMSST cannot effectively identify the multi-component signals with weak amplitude components. The proposed AR-EWT+LMSST method is compared with some advanced time-frequency analysis techniques such as synchrosqueezing transform (SST), synchroextracting transform (SET), and LMSST. The results demonstrate that the proposed AR-EWT+LMSST method can improve the accuracy of identified IFs. The effectiveness and applicability of the proposed method are validated through a multi-component signal, a VBI numerical model with a four-degree-of-freedom half-car, and a VBI model experiment. The effect of vehicle characteristics, vehicle speed, and road surface roughness on the identified IFs of bridge are investigated.

• 한국언론정보학보
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• 제78권
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• pp.79-115
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• 2016

이 연구는 마포 FM에 대한 사례연구를 통해 대안 미디어, 테크놀로지, 그리고 콘텐츠 중심의 논의로 치우쳐져 있는 기존의 공동체 라디오 연구의 한계를 넘어서려는 시도를 한다. 지역 공동체의 구성원들이 방송 제작에 직접 참여함으로써 스스로 문화적 정체성을 재구성해낸다는 측면에서 공동체 라디오는 구성원들의 문화적 실천을 엮어내는 역할을 한다고 할 수 있다. 즉 지역 공동체 구성원들이 공동체 라디오를 전유하고 이를 통해 스스로 정체성을 재구성해내는 양상들은 공동체 라디오의 정체성을 재조명할 수 있게 하는 단초를 제공해준다. 심층 인터뷰를 동원한 현장연구 결과에 따르면, 공동체 라디오는 참여형 제작과정이라는 문화적 실천을 통해서 엮이게 되는 - 즉 지역 공동체 구성원들과의 상호작용이라는 측면에서 - 삶이 묻어나는 매체인 동시에, 지역성과 대안성이라는 특성을 넘어 시민성과 공동체성과 관계망의 형성에 기여하는 미디어, 즉 사회적 유대감과 연대를 형성하는 데에 기여하는 미디어라고 재정의 할 수 있다.