• Title, Summary, Keyword: non-response

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Analysis on the Effect of Unit Non-Response Adjustment using the Survey of Household Finances (가계금융조사를 활용한 단위무응답 조정효과 분석)

  • Baek, Jeeseon;Shim, Kyuho
    • The Korean Journal of Applied Statistics
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    • v.26 no.3
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    • pp.375-387
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    • 2013
  • Unit non-response of surveys reduces the efficiency of the estimates and also causes non-response bias especially when there is large difference between respondents and non-respondents. Non-response weighting adjustments have usually been used to compensate for non-response. It is not easy to examine the non-response bias as well as to obtain information on the non-respondents in sample surveys. A household panel survey, called The Survey of Household Finances, was conducted in both 2010 and 2011. In this paper, we assume that non-response households in Wave 2 have strong non-response (non-cooperative) tendency. We classify those households into non-response households in Wave 1. Under this assumption, the characteristics of non-response households, the non-response bias and the effect of non-response adjustments are investigated.

Structural Optimization of Truss with Non-Linear Response Using Equivalent Linear Loads (선형등가하중을 이용한 비선형 거동을 하는 트러스 구조물의 최적설계)

  • Park, Ki-Jong;Park, Gyung-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.4
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    • pp.467-474
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    • 2004
  • A numerical method and algorithms is proposed to perform optimization of non-linear response structures. An analytical and numerical method based finite element method is also proposed for the transformation of non-linear response into linear response. Loads transformed from this method are defined as the equivalent linear loads. With the loads and the transformed response, linear static optimization is performed for nonlinear response structure with geometric and/or material non-linearity. The results of the optimization are compared with them of typical non-linear response optimization using finite difference method. The proposed method is very efficient and derives good solution.

Structural Optimization of Truss with Non-Linear Response Using Equivalent Static Loads (등가정하중을 이용한 비선형 거동 트러스 구조물의 최적설계)

  • Park, Ki-Jong;Park, Gyung-Jin
    • Proceedings of the KSME Conference
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    • pp.999-1004
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    • 2004
  • A numerical method and algorithms is proposed to perform optimization of non-linear response structures. An analytical and numerical method based finite element method is also proposed for the transformation of non-linear response into linear response. Loads transformed from this method are defined as the equivalent linear loads. With the loads and the transformed response, linear static optimization is performed for nonlinear response structure with geometric and/or material non-linearity. The results of the optimization are compared with them of typical non-linear response optimization using finite difference method. The proposed method is very efficient and derives good solution.

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Modeling of non-ideal frequency response in capacitive MEMS resonator (정전 용량형 MEMS 공진기의 비이상적 주파수 응답 모델링)

  • Ko, Hyoung-Ho
    • Journal of Sensor Science and Technology
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    • v.19 no.3
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    • pp.191-196
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    • 2010
  • In this paper, modeling of the non-ideal frequency response, especially "notch-and-spike" magnitude phenomenon and phase lag distortion, are discussed. To characterize the non-ideal frequency response, a new electro-mechanical simulation model based on SPICE is proposed using the driving loop of the capacitive vibratory gyroscope. The parasitic components of the driving loop are found to be the major factors of non-ideal frequency response, and it is verified with the measurement results.

Nonlinear response of stiffened triceratops under impact and non-impact waves

  • Chandrasekaran, Srinivasan;Nassery, Jamshed
    • Ocean Systems Engineering
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    • v.7 no.3
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    • pp.179-193
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    • 2017
  • Dynamic response analysis of offshore triceratops with stiffened buoyant legs under impact and non-impact waves is presented. Triceratops is relatively new-generation complaint platform being explored in the recent past for its suitability in ultra-deep waters. Buoyant legs support the deck through ball joints, which partially isolate the deck by not transferring rotation from legs to the deck. Buoyant legs are interconnected using equally spaced stiffeners, inducing more integral action in dispersing the encountered wave loads. Two typical nonlinear waves under very high sea state are used to simulate impact and non-impact waves. Parameters of JONSWAP spectrum are chosen to produce waves with high vertical and horizontal asymmetries. Impact waves are simulated by steep, front asymmetric waves while non-impact waves are simulated using Stokes nonlinear irregular waves. Based on the numerical analyses presented, it is seen that the platform experiences both steady state (springing) and transient response (ringing) of high amplitudes. Response of the deck shows significant reduction in rotational degrees-of-freedom due to isolation offered by ball joints. Weak-asymmetric waves, resulting in non-impact waves cause steady state response. Beat phenomenon is noticed in almost all degrees-of-freedom but values in sway, roll and yaw are considerably low as angle of incidence is zero degrees. Impact waves cause response in higher frequencies; bursting nature of pitch response is a clear manifestation of the effect of impact waves on buoyant legs. Non-impact waves cause response similar to that of a beating phenomenon in all active degrees-of-freedom, which otherwise would not be present under normal loading. Power spectral density plots show energy content of response for a wide bandwidth of frequencies, indicating an alarming behaviour apart from being highly nonlinear. Heave, being one of the stiff degrees-of-freedom is triggered under non-impact waves, which resulted in tether tension variation under non-impact waves as well. Reduced deck response aids functional requirements of triceratops even under impact and non-impact waves. Stiffened group of buoyant legs enable a monolithic behaviour, enhancing stiffness in vertical plane.

A Study on Evaluation of Horizontal Force of Non-structural Components Considering Predominant Periods of Seismic Waves (지진파 탁월주기를 고려한 비구조요소의 수평설계지진력 평가)

  • Oh, Sang Hoon;Kim, Ju Chan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.24 no.6
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    • pp.267-275
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    • 2020
  • In the event of an earthquake, non-structural components require seismic performance to ensure evacuation routes and to protect lives from falling non-structural components. Accordingly, the seismic design code proposes horizontal force for the design and evaluation of non-structural components. Ground motion observed on each floor is affected by a building's eigen vibration mode. Therefore, the earthquake damage of non-structural components is determined by the characteristics of the non-structural component system and the vibration characteristics of the building. Floor response spectra in the seismic design code are estimated through time history analysis using seismic waves. However, it is difficult to use floor response spectra as a design criterion because of user-specific uncertainties of time history analysis. In addition, considering the response characteristics of high-rise buildings to long-period ground motions, the safety factor of the proposed horizontal force may be low. Therefore, this study carried out the horizontal force review proposed in the seismic design code through dynamic analysis and evaluated the floor response of seismic waves considering buildings and predominant periods of seismic waves.

Non-piezoelectric effects in piezoresponse force microscopy

  • Seol, Daehee;Kim, Bora;Kim, Yunseok
    • Current Applied Physics
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    • v.17 no.5
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    • pp.661-674
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    • 2017
  • Piezoresponse force microscopy (PFM) has been used extensively for exploring nanoscale ferro/piezoelectric phenomena over the past two decades. The imaging mechanism of PFM is based on the detection of the electromechanical (EM) response induced by the inverse piezoelectric effect through the cantilever dynamics of an atomic force microscopy. However, several non-piezoelectric effects can induce additional contributions to the EM response, which often lead to a misinterpretation of the measured PFM response. This review aims to summarize the non-piezoelectric origins of the EM response that impair the interpretation of PFM measurements. We primarily discuss two major non-piezoelectric origins, namely, the electrostatic effect and electrochemical strain. Several approaches for differentiating the ferroelectric contribution from the EM response are also discussed. The review suggests a fundamental guideline for the proper utilization of the PFM technique, as well as for achieving a reasonable interpretation of observed PFM responses.

Response Modification Factors of Non-seismic School Buildings Considering Short Column Effects and Natural Period (단주효과 및 고유주기를 고려한 비내진 학교시설의 반응 수정계수)

  • Kim, Beom Seok;Park, Ji-Hun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.23 no.4
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    • pp.201-209
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    • 2019
  • Response modification factors of school facilities for non-seismic RC moment frames with partial masonry infills in 'Manual for Seismic Performance Evaluation and Retrofit of School Facilities' published in 2018 were investigated in the preceding study. However, since previous studies are based on 2D frame analysis and limited analysis conditions, additional verification needs to be performed to further apply various conditions including orthogonal effect of seismic load. Therefore, this study is to select appropriate response modification factors of school facilities for non-seismic RC moment frames with partial masonry infills by 3D frame analysis. The results are as follows. An appropriate response modification factor for non-seismic RC moment frames with partial masonry infills is proposed as 2.5 for all cases if the period is longer than 0.6 seconds. Also if the period is less than 0.4 seconds and the ratio of shear-controlled columns is less than 30%, 2.5 is chosen too. However, if the period is less than 0.4 seconds and the ratio of shear-controlled columns is higher than 30%, the response modification factor shall be reduced to 2.0. If the period is between 0.4 and 0.6 seconds, then linearly interpolates the response correction factor.

An estimation method for non-response model using Monte-Carlo expectation-maximization algorithm (Monte-Carlo expectation-maximaization 방법을 이용한 무응답 모형 추정방법)

  • Choi, Boseung;You, Hyeon Sang;Yoon, Yong Hwa
    • Journal of the Korean Data and Information Science Society
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    • v.27 no.3
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    • pp.587-598
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    • 2016
  • In predicting an outcome of election using a variety of methods ahead of the election, non-response is one of the major issues. Therefore, to address the non-response issue, a variety of methods of non-response imputation may be employed, but the result of forecasting tend to vary according to methods. In this study, in order to improve electoral forecasts, we studied a model based method of non-response imputation attempting to apply the Monte Carlo Expectation Maximization (MCEM) algorithm, introduced by Wei and Tanner (1990). The MCEM algorithm using maximum likelihood estimates (MLEs) is applied to solve the boundary solution problem under the non-ignorable non-response mechanism. We performed the simulation studies to compare estimation performance among MCEM, maximum likelihood estimation, and Bayesian estimation method. The results of simulation studies showed that MCEM method can be a reasonable candidate for non-response model estimation. We also applied MCEM method to the Korean presidential election exit poll data of 2012 and investigated prediction performance using modified within precinct error (MWPE) criterion (Bautista et al., 2007).

A study on response analysis of submerged floating tunnel with linear and nonlinear cables

  • Yarramsetty, Poorna Chandra Rao;Domala, Vamshikrishna;Poluraju, P.;Sharma, R.
    • Ocean Systems Engineering
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    • v.9 no.3
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    • pp.219-240
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    • 2019
  • This paper presents the comparison between SFT response with linear and nonlinear cables. The dynamic response analysis of submerged floating tunnel (SFT) is presented computationally with linear and nonlinear tension legs cables. The analysis is performed computationally for two wave directions one at 90 degrees (perpendicular) to tunnel and other at 45 degrees to the tunnel. The tension legs or cables are assumed as linear and non- linear and the analysis is also performed by assuming one tension leg or cable is failed. The Response Amplitude Operators (RAO's) are computed for first order waves, second order waves for both failure and non-failure case of cables. For first order waves- the SFT response is higher for sway and heave degree of freedom with nonlinear cables as compared with linear cables. For second order waves the SFT response in sway degree of freedom is bit higher response with linear cables as compared with nonlinear cables and the SFT in heave degree of freedom has higher response at low time periods with nonlinear cables as compared with linear cables. For irregular waves the power spectral densities (PSD's) has been computed for sway and heave degrees of freedom, at $45^0$ wave direction PSD's are higher with linear cables as compared with nonlinear cables and at $90^0$ wave direction the PSD's are higher with non-linear cables. The mooring force responses are also computed in y and z directions for linear and nonlinear cables.