• Title/Summary/Keyword: local interaction

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A Study on Measuring the Publicness of Public Libraries: Based on the Perception of Local Residents (공공도서관 공공성 측정 연구 - 지역 주민의 인식을 기반으로 -)

  • Hyeyoung Kim;Giyeong Kim
    • Journal of the Korean Society for Library and Information Science
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    • v.57 no.2
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    • pp.241-269
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    • 2023
  • This study developed a scale for measuring publicness and examined the differences in perception of publicness according to library usage experience, personal characteristics of local residents, and types of library services. The survey was conducted on 15 local public libraries in 5 districts of Seoul, targeting library users and local residents. As a result, it was found that the publicness of libraries is composed of three factors: participatory responsiveness, procedural fairness, and situational equality, which demonstrate different aspects formed through the interaction between library users and local residents in the local community. The study derived ways to enhance publicness and presented in detail which aspect of publicness needs to be enhanced according to library usage experience and service period, local residents' occupational environment and experience of local activities, and types of library services. The study suggests that when service experiences that enhance publicness are effectively provided, more local residents can benefit from them, and the value of the library's existence can be demonstrated.

Numerical Prediction of Unsteady Transitional Boundary Layer Flows due to Rotor-Stator Interaction(II)-Characteristics of Unsteady Transitional Boundary Layer Flow- (정익과 동익의 상호작용에 의한 비정상 천이 경계층 유동의 수치해석에 관한 연구 (II))

  • Kang, Dong-Jin;Lakshminarayana, Budugur
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.6
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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.

Effects of Slot Configurations on the Passive Control of Oblique-Shock-Interaction Flows (슬롯 형상이 경사충격파 간섭유동의 피동제어에 미치는 영향에 관한 연구)

  • Jang, Seong-Ha;Lee, Yeol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.12
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    • pp.18-24
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    • 2006
  • Passive control of the shock wave/turbulent boundary-layer interaction utilizing slotted plates and a porous plate over a cavity has been carried out. Effect of various slot configurations on the characteristics of the interaction has been observed. Pitot/wall surface pressure distributions and flow visualizations including Schlieren images, kerosene-lampblack tracings and interference fringe patterns over a thin oil-film have been obtained at the downstream of the shock interactions. For the streamwise-slot configuration, a local higher pitot pressure was noticed at the downstream of the interaction as compared with the case of no control, however, not much improvement in pitot pressure was observed for the spanwise-slot configuration.

A study of wind turbine power generation and turbine/tower interaction using large eddy simulation

  • Howard, R.J.A.;Pereira, J.C.F.
    • Wind and Structures
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    • v.9 no.2
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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.

Occurrence mechanism of recent large earthquake ground motions at nuclear power plant sites in Japan under soil-structure interaction

  • Kamagata, Shuichi;Takeqaki, Izuru
    • Earthquakes and Structures
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    • v.4 no.5
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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.

THE FUNDAMENTAL SHOCK-VORTEX INTERACTION PATTERNS THAT DEPEND ON THE VORTEX FLOW REGIMES

  • Chang, Keun-Shik;Barik, Hrushikesh;Chang, Se-Myong
    • Journal of computational fluids engineering
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    • v.14 no.3
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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.

Numerical Study of Interaction between Hydrogen and Hydrocarbon Flames (수소화염과 탄화수소화염의 상호작용에 관한 수치계산 연구)

  • Oh, Chang-Bo;Lee, Eui-Ju
    • Journal of the Korean Society of Safety
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    • v.25 no.2
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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.

Influence of picture presence in reviews on online seller product rating: Moderation role approach

  • Hossin, Md Altab;Mu, Yinping;Fang, Jiaming;Frimpong, Adasa Nkrumah Kofi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.12
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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.

Time-varying characteristics analysis of vehicle-bridge interaction system using an accurate time-frequency method

  • Tian-Li Huang;Lei Tang;Chen-Lu Zhan;Xu-Qiang Shang;Ning-Bo Wang;Wei-Xin Ren
    • Smart Structures and Systems
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    • v.33 no.2
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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.

Community Radio's Interaction with Local Community Residents A Field Report on Mapo FM's Case (공동체 라디오와 지역 공동체 구성원의 상호작용에 대한 현장연구 마포 FM 사례를 중심으로)

  • Ban, Myeong Jin;Kim, Young Chan
    • Korean journal of communication and information
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    • v.78
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    • pp.79-115
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    • 2016
  • This study, by proposing a case study of community radio, attempts to expand the horizon of academic and social discussion on the medium that has been disproportionately skewed towards discourses on alternative media, technology, and programming content. As residents of local community actively participate in the production process, they reconstruct their cultural identities. In that sense, community radio is a medium that makes it possible the re-negotiation and reconfiguration of cultural identities of local residents. That is to say, a case study on the specific ways in which community residents appropriate community radio in reconstructing their identities offers us some entry points where we may come up with a new perspective on the identity of community radio. The results of fieldwork show that community radio, as it is closely intertwined with the residents' participatory cultural practices, is a medium of 'lived culture' -i.e., a medium that contributes to the making of civility, communitarianism, and social network. Community radio, then, may be redefined as an interactive medium that contributes to the formation of social rapport and solidarity.

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