• Title/Summary/Keyword: difference in difference estimation

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Hierarchical Bayesian Analysis of Spatial Data with Application to Disease Mapping

  • Kim, Dal-Ho;Kang, Sang-Gil
    • Communications for Statistical Applications and Methods
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    • v.6 no.3
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    • pp.781-790
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    • 1999
  • In this paper we consider estimation of cancer incidence rates for local areas. The raw estimates usually are based on small sample sizes and hence are usually unreliable. A hierarchical Bayes generalized linear model is used which connects the local areas thereby enabling one to 'borrow strength' Random effects with pairwise difference priors model the spatial structure in the data. The methods are applied to cancer incidence estimation for census tracts in a certain region of the state of New York.

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Parameter Estimation of Shallow Arch Using Quantum-Inspired Evolution Algorithm (양자진화 알고리즘을 이용한 얕은 아치의 파라미터 추정)

  • Shon, Sudeok;Ha, Junhong
    • Journal of Korean Association for Spatial Structures
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    • v.20 no.1
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    • pp.95-102
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    • 2020
  • The structural design of arch roofs or bridges requires the analysis of their unstable behaviors depending on certain parameters defined in the arch shape. Their maintenance should estimate the parameters from observed data. However, since the critical parameters exist in the equilibrium paths of the arch, and a small change in such the parameters causes a significant change in their behaviors. Thus, estimation to find the critical ones should be carried out using a global search algorithm. In this paper we study the parameter estimation for a shallow arch by a quantum-inspired evolution algorithm. A cost functional to estimate the system parameters included in the arch consists of the difference between the observed signal and the estimated signal of the arch system. The design variables are shape, external load and damping constant in the arch system. We provide theoretical and numerical examples for estimation of the parameters from both contaminated data and pure data.

Study on Correlation Between Timber Age, Image Bands and Vegetation Indices for Timber Age Estimation Using Landsat TM Image (Landsat TM 영상을 이용한 교목연령 추정에 영창을 주는 영상 밴드 및 식생지수에 관한 연구)

  • Lee, Jung-Bin;Heo, Joon;Sohn, Hong-Gyoo
    • Korean Journal of Remote Sensing
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    • v.24 no.6
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    • pp.583-590
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    • 2008
  • This study presents a correlation between timber Age, image bands and vegetation indices for timber age estimation. Basically, this study used Landsat TM images of three difference years (1994, 1994, 1998) and difference between Shuttle Radar Topography Mission (SRTM) and National Elevation Dataset (NED). Bands of 4, 5 and 7, Normalized Difference Vegetation Index (NDVI), Infrared Index (II), Vegetation Condition Index (VCI) and Soil Adjusted Vegetation Index (SA VI) were obtained from Landsat TM images. Tasseled cap - greenness and wetness images were also made by Tasseled cap transformation. Finally, analysis of correlation between timber age, difference between Shuttle Radar Topography Mission (SRTM) and National Elevation Dataset (NED), individual TM bands (4, 5, 7), Normalized Difference Vegetation Index (NDVI), Tasseled cap-Greenness, Wetness, Infrared Index (II), Vegetation Condition Index (VCI) and Soil Adjusted Vegetation Index (SAVI) using regression model. In this study about 1,992 datasets were analyzed. The Tasseled cap - Wetness, Infrared Index (II) and Vegetation Condition Index (VCI) showed close correlation for timber age estimation.

Computationally Efficient Estimation Algorithm for Unknown location of an Earth Station (지구국 위치 추적을 위한 효율적인 계산 알고리즘)

  • Cho, Se-Young;Kim, Soo-Young;Park, Se-Kyoung;Park, Kwang-Ryang
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.8
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    • pp.16-23
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    • 2010
  • In this paper, we propose an efficient estimation algorithm to find unknown location of an earth station for a geostationary satellite system. A cross ambiguity function (CAF), using time difference of arrival (TDOA) and frequency difference arrival (FDOA), is usually used to estimate the unknown location of an unauthorized earth station which may invoke interference to the existing satellite systems. However, a practical estimation of the location data requires tremendous computational time of CAF, and this prohibits direct utilization of CAF. For this reason, we propose a computationally efficient algorithm which utilizes characteristics of TDOA and FDOA within CAF. The proposed algorithm greatly enhances the computational efficiency without any performance degradation. In addition, we demonstrate the simulation results on the estimation performance by the resolution of the CAF estimation. The results provided in this paper will be utilized at the real system implementation.

Multi-Modal User Distance Estimation System based on Mobile Device (모바일 디바이스 기반의 멀티 모달 사용자 거리 추정 시스템)

  • Oh, Byung-Hun;Hong, Kwang-Seok
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.2
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    • pp.65-71
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    • 2014
  • This paper present the multi-modal user distance estimation system using mono camera and mono microphone basically equipped with a mobile device. In case of a distance estimation method using an image, we is estimated a distance of the user through the skin color region extraction step, a noise removal step, the face and eyes region detection step. On the other hand, in case of a distance estimation method using speech, we calculates the absolute difference between the value of the sample of speech input. The largest peak value of the calculated difference value is selected and samples before and after the peak are specified as the ROI(Region of Interest). The samples specified perform FFT(Fast Fourier Transform) and calculate the magnitude of the frequency domain. Magnitude obtained is compared with the distance model to calculate the likelihood. We is estimated user distance by adding with weights in the sorted value. The result of an experiment using the multi-modal method shows more improved measurement value than that of single modality.

A Study on the Estimation of Lane position using difference of Intensity (Intensity차를 이용한 차선의 위치 검출에 관한 연구)

  • 손경희;송현승;노도환
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.403-403
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    • 2000
  • Generally estimation of driving direction uses the way which uses lane detection and vanishing point in autonomous-driving system. Especially we use Sub-window for decreasing Process time when we detect lane, but fixed sub-window can not detect lane because of some factors in road image. So we suggest algorithm using one-dimension line scan method to detect an exact position of lane.

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The Estimation of Directions of Arrival of Multiple Sky Waves Using MUSIC Algorithm (MUSIC 알고리듬을 이용한 공간파 신호의 도래각 추정)

  • 채종석;박형래;이혁재;박한규
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.9
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    • pp.1134-1140
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    • 1988
  • In this paper, the theory of superresolution algorithms for estimation of directions of arrival of signals using eigen-structure analysis (mainly MUSIC algorithm)is described. Also, we apply MUSIC algorithm to circularly disposed antenna system, and simulate the angular resolution according to relative azimuth difference, S/N ratio, number of snapshots, so that we confirm the possibility of applications of MUSIC algorithm to sky wave in real situations.

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Analysis of Age Estimation Cases of Living Body Based on Dental aspect in Jeollabuk-do (전라북도 지역의 치과적 생체 연령추정 사례의 분석)

  • Eom, Ae-Ja;Suh, Bong-Jik
    • Journal of Oral Medicine and Pain
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    • v.33 no.2
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    • pp.167-176
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    • 2008
  • We analyzed 121 age estimation clients who had visited oral medicine clinic, Chonbuk National University Hospital, from January 2000 to December 2007 to evaluate its characters in Jeonllabuk-do. The obtained results were as follows : 1. There was distinct difference in sex distribution(Male : 58.7%, Female : 41.3%) and more than half percent(55.4%) was over 50's. 2. The difference between registered and alleged age was the most in more than 5 years, and most of them were over 50's. 3. There were more clients who wanted to increase their age than to decrease and was no prominent difference in sex. Age estimation clients who wanted to decrease their age were predominant under 10 years old and in 20's, and those wanted to increase were predominant in 10's and over 30's. 4. The most reasons to correct age were related to welfare benefit. The purpose of age estimation was different according to each age groups; welfare benefit was the most over 50's, occupation in 40's and 50's, friendship in 30's and 40's, sibling-related in 50's, employment in 10's and 20's. 5. Age was estimated by the attrition of permanent tooth and pulp/tooth ratio from 20 years, root apex closure for 10's and calcification of permanent tooth under 10 years old. In cases that were difficult to estimate by use of the attrition of permanent tooth and pulp/tooth ratio, age was estimated by missing time of permanent tooth and the change of mandibular angle with age. 6. The estimated ages were close to alleged age in 77.7% of clients but the rest(22.3%) was close to registered age.

Fast Block Motion Estimation based on reduced search ranges in MPEG-4 (탐색 영역 재설정을 이용한 고속 움직임 예측 방법)

  • Kim, Sung-Jai;Seo, Dong-Wan;Choe, Yoon-Sik
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.529-531
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    • 2005
  • A block-based fast motion estimation algorithm is proposed in this paper to perform motion estimation based on the efficiently reduced search ranges in MPEG-4(ERS). This algorithm divides the search areas into several small search areas and the candidate small search area that has the lowest average of sum norm difference between current macroblock and candidate macroblock is chosen to perform block motion estimation using the Nobel Successive Elimination Algorithm (NSEA). Experimental results of the proposed algorithm show that the averaging PSNR improvement is better maximum 0.125 dB than other tested algorithms and bit saving effect is maximum 20kbps for some tested sequences in low-bit rate circumstance.

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Performance bounds of optimal FIR filter-under modeling uncertainty (모델 불확실성에 대한 초적 FIR 필터의 성능한계)

  • 유경상;권오규
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.64-69
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    • 1993
  • In this paper we present the performance bounds of the optimal FIR filter in continuous time systems with modeling uncertainty. The performance measure bounds are calculated from the estimation error covariance bounds of the optimal FIR filter and the suboptimal FIR filter. Performance error bounds range are expressed by the upper bounds on the estimation error covariance difference between the real and nominal values in case of the systems with noise uncertainty or model uncertainty. The performance bounds of the systems are derived on the assumption that the system uncertainty and the estimation error covariance are imperfectly known a priori. The estimation error bounds of the optimal FIR filter is compared with those of the Kalman filter via a numerical example applied to the estimation of the motion of an aircraft carrier at sea, which shows the former has better performances than the latter.

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