• Title, Summary, Keyword: estimation

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An OFDM Frequency Offset Estimation Scheme Robust to Timing Error (시간 오차에 강인한 OFDM 주파수 옵셋 추정 기법)

  • Kim Sang-Hun;Yoon Seok-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.6C
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    • pp.623-628
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    • 2006
  • This paper addresses the frequency offset estimation problem in the presence of the timing error for OFDM systems. When the timing error exists, the correlation value used for the frequency offset estimation could be reduced significantly due to the timing error, resulting in considerable degradation in estimation performance. In this paper, using the coherence phase bandwidth (CPB) and a threshold, a novel frequency offset estimation scheme is proposed and based on which, an efficient timing error estimation scheme is also proposed for the re-estimation of the frequency offset. The performance comparison results show that the proposed frequency offset estimation scheme is not only more robust to the timing error but also has less computational complexity, as compared with the conventional schemes. It is also demonstrated by simulation that theproposed timing error estimation scheme gives a reliable estimate of the timing error.

Robust 2D human upper-body pose estimation with fully convolutional network

  • Lee, Seunghee;Koo, Jungmo;Kim, Jinki;Myung, Hyun
    • Advances in robotics research
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    • v.2 no.2
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    • pp.129-140
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    • 2018
  • With the increasing demand for the development of human pose estimation, such as human-computer interaction and human activity recognition, there have been numerous approaches to detect the 2D poses of people in images more efficiently. Despite many years of human pose estimation research, the estimation of human poses with images remains difficult to produce satisfactory results. In this study, we propose a robust 2D human body pose estimation method using an RGB camera sensor. Our pose estimation method is efficient and cost-effective since the use of RGB camera sensor is economically beneficial compared to more commonly used high-priced sensors. For the estimation of upper-body joint positions, semantic segmentation with a fully convolutional network was exploited. From acquired RGB images, joint heatmaps accurately estimate the coordinates of the location of each joint. The network architecture was designed to learn and detect the locations of joints via the sequential prediction processing method. Our proposed method was tested and validated for efficient estimation of the human upper-body pose. The obtained results reveal the potential of a simple RGB camera sensor for human pose estimation applications.

A Study on the Contents of Computation Estimation in Elementary School Mathematics Textbooks (초등교과서 연산 단원에서의 계산어림 지도 내용에 대한 고찰)

  • Kwon, Sungyong
    • Journal of Elementary Mathematics Education in Korea
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    • v.24 no.1
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    • pp.53-87
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    • 2020
  • The purpose of this study was to find a future direction for improving computational estimation instruction through examining the contents of computational estimation included in the 2015 revised elementary school mathematics curriculum and elementary school mathematics textbook and teacher's guide. Through this, several suggestions was made as follow. Firs, it is necessary to emphasize the computational estimation across all grade groups. Second, it is necessary to teach the computational estimation strategies systematically. It was found that it is necessary to reinforce the activities related to computational estimation in the computation related units.

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Receding Horizon FIR Parameter Estimation for Stochastic Systems

  • Lee, Kwan-Ho;Han, Soo-Hee;Lee, Changhun;Kwon, Wook-Hyun
    • 제어로봇시스템학회:학술대회논문집
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    • pp.159.1-159
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    • 2001
  • A new time-domain FIR parameter estimation called the receding horizon least square estimation (RHLSE) is suggested for stochastic systems by combining the well known least square estimation with the receding horizon strategy. It can be always obtained without the requirement of any \textit{a priori} information about the horizon initial parameter. A fast algorithm for the suggested estimation is also presented which is remarkable in the view of computational advantage and simple implementation. It is shown that the proposed estimation is robust against temporary modeling uncertainties due to their FIR structure through simulation studies.

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Real-Time Identification and Estimation of Transformer Tap Ratios Containing Errors

  • Kim, Hongrae;Kwon, Hyung-Seok
    • KIEE International Transactions on Power Engineering
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    • v.2A no.3
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    • pp.109-113
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    • 2002
  • This paper addresses the issue of parameter error identification and estimation in electric power systems. Parameter error identification and estimation is carried out as a part of the state estimation. A two stage estimation procedure is used to detect and identify parameter errors. Suspected parameters are identified by the WLAV state estimator in the first stage. A new WLAV state estimator adding suspected system parameters in the state vector is used to estimate the exact values of parameters. Supporting examples are given by using the IEEE 14 bus system.

Research for experimental methods of mechanical parameters estimation of the mobile robots (로봇의 기구학적 계수 추정을 위한 실험적 방법에 대한 연구)

  • Choi, Jong-Mi;Park, Joong-Un;Lee, Ji-Hong;Kim, Ji-Yong
    • Proceedings of the IEEK Conference
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    • pp.106-108
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    • 2009
  • In this paper, we handle automatic estimation of mechanical parameters for mobile robots. Most estimation methods are based on the sequence and move-measurement-estimation. Estimated accuracy is largely dependent on the paths. Mathematical conditions minimizing estimation errors are derived, and then a method finding optimal paths for mechanical parameters estimation is proposed.

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A Joint Channel Estimation and Data Detection for a MIMO Wireless Communication System via Sphere Decoding

  • Patil, Gajanan R.;Kokate, Vishwanath K.
    • Journal of Information Processing Systems
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    • v.13 no.4
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    • pp.1029-1042
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    • 2017
  • A joint channel estimation and data detection technique for a multiple input multiple output (MIMO) wireless communication system is proposed. It combines the least square (LS) training based channel estimation (TBCE) scheme with sphere decoding. In this new approach, channel estimation is enhanced with the help of blind symbols, which are selected based on their correctness. The correctness is determined via sphere decoding. The performance of the new scheme is studied through simulation in terms of the bit error rate (BER). The results show that the proposed channel estimation has comparable performance and better computational complexity over the existing semi-blind channel estimation (SBCE) method.

The Least Absolute Deviations Estimation of the Contingent Valuation Model (조건부가치측정모형의 최소절대편차추정)

  • Kim, Dongil
    • Environmental and Resource Economics Review
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    • v.10 no.4
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    • pp.515-545
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    • 2001
  • This paper introduces the least absolute deviations estimation of the contingent valuation model, which corresponds to the semi-parametric estimation of discrete choice models by Manski (1975, 1985) and Lee (1992). The least absolute deviations estimation is more robust to mis-specified distributional assumptions in the estimation of the contingent valuation model, compared to the maximum likelihood estimation. The full identification and strong consistency of the estimation are proved and its application to different formats of contingent valuation survey data is discussed. Simulation studies are designed to evaluate its operational characteristics including computational strategies, small sample properties and the efficiency gain of a follow-up question. The bias and efficiency of least absolute deviations and maximum likelihood estimation are compared in the presence of heteroskedasticity.

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A Study on Monthly Electric Energy Estimation of Pole-Transformer Using NLRE Curve (NLRE 곡선을 이용한 주상 변압기 월간 사용전력량 추정에 관한 연구)

  • Im, Jin-Soon;Yun, Sang-Yun;Kim, Jae-Chul
    • Proceedings of the KIEE Conference
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    • pp.58-60
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    • 2000
  • In this paper we present an estimation method of electric energy[kWh] for load management of pole-transformer. For the electric energy estimation, we use the nonlinear load research based estimation(NLRE) algorithm. The NLRE curve is the normalized annual cumulative energy consumption for a particular day in a year. And, it is used for the coefficient estimation. Estimation method of suggested electric energy of pole-transformer used billing cycle electric energy estimation equation is verified as comparison billing cycle electric energy and estimated electric energy. We can reduce the error of peak load estimation by suggested method than the conventional method in domestic.

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An Empirical Study On Information Systems Operation Cost Estimation Model (정보시스템 운영사업 비용산정 모형 개발에 대한 실증적 연구)

  • Kim, Hyeon-Su
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.6
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    • pp.1810-1817
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    • 2000
  • The purpose of this research is to develop an estimation model for information systems operating costs. Current cost estimation practices and types of sytem management projects have been reviewed an analyses. Typical operating project types of information systems are determined. They are application system operation, help disk operation, network management and operation, and hardware management. For each type of projects, cost factors ar identified and a structure of cost estimation model is defined. Cost estimation models have been constructed and tested by 24 real operation projects data. Statistical analysis shows derived models are statistically significant. User groups' opinion on these draft cost estimation model has been surveyed and summarized. The results of this research can be used as a cornerstone for future research on operating cost estimation, and for cost estimation guideline of information systems operation projects.

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