• Title/Summary/Keyword: frequency-response

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VSimulators: A New UK-based Immersive Experimental Facility for Studying Occupant Response to Wind-induced Motion of Tall Buildings

  • Antony Darby;James Brownjohn;Erfan Shahabpoor;Kaveh Heshmati
    • International Journal of High-Rise Buildings
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    • v.11 no.4
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    • pp.347-362
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    • 2022
  • Current vibration serviceability assessment criteria for wind-induced vibrations in tall buildings are based largely on human 'perception' thresholds which are shown not to be directly translatable to human 'acceptability' of vibrations. There is also a considerable debate about both the metrics and criteria for vibration acceptability, such as frequency of occurrence or peak vs mean vibration, and how these might vary with the nature of the vibration. Furthermore, the design criteria are necessarily simplified for ease of application so cannot account for a range of environmental, situational and human factors that may enhance or diminish the impact of vibrations on serviceability. The dual-site VSimulators facility was created specifically to provide an experimental platform to address gaps in understanding of human response to building vibration. This paper considers how VSimulators can be used to inform general design guidance and support design of specific buildings for habitability, in terms of vibration, which allow engineers and clients to make informed decisions with regard to sustainable design, in terms of energy and financial cost. This paper first provides a brief overview of current vibration serviceability assessment guidelines, and the current understanding and limitations of occupants' acceptability of wind-induced motion in tall buildings. It then describes how the dual-site VSimulators facility at the Universities of Bath and Exeter can be used to assess the effects of motion and environment on human comfort, wellbeing and productivity with examples of how the facility capabilities have been used to provide new, human experience based experimental research approaches.

Suggestion of Logic to Control Power Plant Equipped ESS in case of Full Open Turbine Control Valve (ESS를 이용한 발전소 터빈제어밸브 전개 운전 제어로직 제안)

  • In Young Chung;Jae-Heon Lee
    • Plant Journal
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    • v.18 no.4
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    • pp.66-72
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    • 2023
  • In order to respond to the demand for flexible operation of thermal power generation, development of natural sliding pressure operation that minimizes throttle loss by opening the turbine control valve 100% and maximize power generation efficiency in conjunction with ESS in order to quickly respond to fluctuations in the system frequency is required. The logic development of natural sliding pressure operation with ESS was developed to modify the existing logic at the power plant's top-level control logic such as the unit master, the boiler master and the turbine master. Cooperative control algorithms that complement the advantages and disadvantages of ESS operation (quick response, limited capacity) and power plant operation (slow response, continuous operation) not only improve efficiency when applied to actual power plants, but also respond quickly and flexibly to load demands to ensure system stability.

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The finite element method for dynamics of FG porous truncated conical panels reinforced with graphene platelets based on the 3-D elasticity

  • Lingqin Xia;Ruiquan Wang;Guang Chen;Kamran Asemi;Abdelouahed Tounsi
    • Advances in nano research
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    • v.14 no.4
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    • pp.375-389
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    • 2023
  • In this study, free vibration analysis of functionally graded (FG) porous truncated conical shell panels reinforced by graphene platelets (GPLs) has been investigated for the first time. Additionally, the effect of three different types of porosity distribution and five different types of GPLs patterns on dynamic response of the shell are also studied. Halpin-Tsai micromechanical model and Voigt's rule are used to determine Young modulus, shear modulus and Poisson's ratio with mass densities of the shell, respectively. The main novelties of present study are: applying 3D elasticity theory and the finite element method in conjunction with Rayleigh-Ritz method to give more accurate results unlike other simplified shell theories, and also presenting a general 3D solution in cylindrical coordinate system that can be used for analyses of different structures such as circular, annular and annular sector plates, cylindrical shells and panels, and conical shells and panels. A convergence study is performed to justify the correctness of the obtained solution and numerical results. The impact of porosity and GPLs patterns, the volume of voids, the weight fraction of graphene nanofillers, semi vertex and span angles of the cone, and various boundary conditions on natural frequencies of the functionally graded panel have been comprehensively studied and discussed. The results show that the most important parameter on dynamic response of FG porous truncated conical panel is the weight fraction of nanofiller and adding 1% weight fraction of nanofiller could increase 57% approximately the amounts of natural frequencies of the shell. Moreover, the porosity distribution has great effect on the value of natural frequency of structure rather than the porosity coefficient.

Comparative research on the preferences and choices of distribution channels depending on the consumption characteristics on fashion consumer - Focused on active Korean and Chinese seniors - (패션 소비자의 유통채널 선호 및 소비 특성에 따른 유통채널 선택에 관한 비교연구 - 한·중 액티브 시니어 비교를 중심으로 -)

  • Sang In Lee;Jihun Yu
    • The Research Journal of the Costume Culture
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    • v.31 no.3
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    • pp.361-378
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    • 2023
  • This research not only determined the preference of fashion brand distribution channels of active Korean and Chinese seniors who became major consumers in the fashion industry, but also analyzed the effect on these preferences and choices of distribution channels depending on personal consumption characteristics and differences between the two groups. Data was collected by a professional survey firm. SPSS 24.0 and AMOS 24.0 were used for empirical analysis, and frequency analysis, multiple response analysis, EFA, reliability analysis, CFA, SEM, and multiple-group comparison analysis were performed. As a result of multiple response analysis, the offline channel was revealed as the preferred fashion distribution channel for active Korean and Chinese seniors; the second most popular was the online channel. The results of multiple-group comparison analysis reveal differences between two groups in seeking emotional consumption via the offline channel; the effect was only evident for active Korean seniors. A difference in seeking emotional consumption via preference for online channel also existed, but only for active Chinese seniors. For these reasons, marketers targeting active Korean seniors will be effective to not only offer brand information by fashion display to let seniors understand the fashion brand, but also to have brand events to form positive emotions toward the fashion brand. Moreover, targeting active Chinese seniors will be necessary to transmit brand sensibility by utilizing metaverse marketing comprising various factors, so that consumers can enjoy the fashion brand.

Spectral Analyses of Ultrashort Pulses Using Recursive Partial-Response Signaling System Model (순환적 PRS 시스템 모델을 이용한 극초단펄스의 스펙트럼 분석)

  • Oh, Yong S.
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.1 no.1
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    • pp.85-93
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    • 1997
  • In this paper, a novel method for obtaining spectra of short pulses is proposed. This method will be well-applied to perform spectral analyses of ultrashort laser pulses which are known to be difficult to evaluate their exact forms in frequency domain because of their narrow-width characteristics in time domain. It must be noted that the method can be represented by a recursive formula derived from the PRS(partial-response signaling) model, and thus more easily available for numerical solutions than the conventional methods such as consecutive differentiations and convolutions. The pulses whose fundamental frames can be exactly determined or approximately represented by truncated Fourier series have well-behaving conditions for applications of this new method. Moreover, the transversal 9-type PRS model can offer various approximations for spectral analyses of ultrashort pulses currently used in transmission systems.

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A Study of Physical Environment of Public Golf Course for Golf Popularization (골프 대중화를 위한 대중제 골프장의 물리적 환경에 관한 연구)

  • Kim, Young-Soo;Jang, Won-Yong
    • Journal of Korea Entertainment Industry Association
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    • v.13 no.8
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    • pp.447-456
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    • 2019
  • This study was to examine the physical environment of public golf course for golf popularization. More specifically, this study was try to analyze the effects of physical environment on customer emotional response, golf course's image and recommendation intention of public golf course. This study were analyzed by frequency analysis, exploratory factor analysis, reliability analysis, correlation and multiple regression analysis. The results were as follows. First, among the physical environmental variables of public golf course, facilities' convenience, cleanliness, and aesthetics had positive effects on customers' positive emotion. Second, among the physical environmental variables of public golf course, facilities' cleanliness had effects on customers' negative emotion. Third, physical environment of public golf course had positive effects on golf course's image. Fourth, physical environment of public golf course had positive effects on recommendation intention.

Development of an Inventory-Based Flood Loss Estimation Method for Rural Areas (인벤토리 기반 농촌지역 홍수손실 평가기법 개발)

  • Kim, Sinae;Lee, Jonghyuk;Jun, Sang-Min;Choi, Won;Kang, Moon-Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.65 no.6
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    • pp.65-78
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    • 2023
  • In recent times, the frequency and intensity of natural disasters, such as heavy rains and typhoons, have been increasing due to the impacts of climate change. This has led to a rise in social and economic damages. Rural areas, in particular, possess limited disaster response capabilities due to their underdeveloped infrastructure and are highly vulnerable to flooding. Therefore, it is crucial to establish preventative and responsive measures. In this study, an Inventory-Based Flood Loss Estimation (IB-FLE) method utilizing high-resolution spatial information was developed for estimating flood-related losses in rural areas. Additionally, the developed approach was applied to a study area and compared with the Multidimensional Flood Damage Analysis (MD-FDA) method. Compared to the MD-FDA, the IB-FLE enables faster and more accurate estimation of flood damages and allows for the assessment of individual building and agricultural land losses using up-to-date information. The findings of this study are expected to contribute to the rational allocation of budgets for rural flood damage prevention and recovery, as well as enhancing disaster response capabilities.

Investigation on organizational culture and sexual harassment in the workplace of dental hygienists (치과위생사의 직장 내 조직문화와 성희롱 실태조사)

  • Ji-Hyoung Han;Ji-Min Hwang
    • Journal of Korean Academy of Dental Administration
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    • v.11 no.1
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    • pp.8-18
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    • 2023
  • The purpose of this study is to examine the organizational culture of dental hospitals and clinics, as well as to assess members' perceptions and actual conditions related to sexual harassment. The research method involved conducting a cross-sectional survey of 149 dental hygienists using random sampling. The analysis utilized frequency analysis and descriptive statistical analysis. Regarding awareness of organizational culture within the workplace, 39.6% responded, "It is difficult to freely use maternity and childcare leave at our workplace". When asked about sexual harassment, 51.7% of respondents said they had received training on sexual harassment prevention. The highest level of sexual harassment experienced was "sexual analogy or evaluation of appearance", at 45.8%. The most common perpetrators of sexual harassment were agency heads and directors, at 37.5%. The most common behavior of the victim at the time was "changing the subject or avoiding the scene" (41.7%). 50.0% of victims of sexual harassment responded to the harm by "just putting up with it". The most common response to the direct and indirect impact of sexual harassment was "there was no specific impact". The most common response from the agency was "there were no suitable measures". Regarding the most necessary policy to prevent sexual harassment, "strict punishment for perpetrators (37.5%)" was the highest. There is a need for organizational and cultural changes to reduce sexual harassment in the workplace. Additionally, it is crucial for the country and society as a whole to actively participate in and improve the system.

Analysis of Volumetric Deformation Influence Factor after Liquefaction of Sand using Cyclic Direct Simple Shear Tests (CDSS 실험을 이용한 모래의 액상화 후 체적변형 영향인자 분석)

  • Herrera, Diego;Kim, Jongkwan;Kwak, Tae-Young;Han, Jin-Tae
    • Journal of the Korean Geotechnical Society
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    • v.40 no.3
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    • pp.65-75
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    • 2024
  • This study investigates liquefaction-induced settlement through strain-controlled tests using a cyclic direct simple shear device on clean sand specimens. By focusing on the accumulated shear strain, soil density, sample preparation method, and cyclic waveshape, this study attempts to enhance the understanding of soil behavior under seismic loading and its further deformation. Results from tests conducted on remolded samples reveal insights into excess pore water pressure development and post-liquefaction volumetric strain behavior, with denser samples exhibiting lower volumetric strains than looser samples. Similarly, the correlation between the frequency and amplitude variations of the wave and volumetric strain highlights the importance of wave characteristics in soil response, with shear strain amplitude changes, varying the volumetric strain response after reconsolidation. In addition, samples prepared under moist conditions exhibit less volumetric strain than dry-reconstituted samples. Overall, the findings of this study are expected to contribute to predictive models to evaluate liquefaction-induced settlement.

Sound Synthesis of Right-Hand Playing Styles Using Improved Physical Modeling of Sanjo Gayageum (개선된 산조 가야금의 물리적 모델링을 이용한 오른손 주법의 음 합성)

  • Cho, Sang-Jin;Chong, Ui-Pil
    • The Journal of the Acoustical Society of Korea
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    • v.25 no.8
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    • pp.362-369
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    • 2006
  • In this paper, we improve a Physical modeling of sanio gayageum and synthesize sounds by right-hand playing styles. Parameters of loop filter are estimated from decay region of recorded sound. That results in improved accuracy and reduction of computational costs. Body is implemented to a resonator which has characteristics of main resonances extracted from impulse response. Residual signal with main resonances removed is used as excitation signal of proposed model. Amok alter is approximated to frequency response of amok and is implemented to the 15th order all-role digital filter. Beating (by middle and index finger) among the right-hand playing styles is represented by feedforward comb filter. Parameters of this filter are extracted from recorded sound. The synthesized sounds using improved physical model of sanjo gayageum. plucking and beating, are pretty similar to original sounds.