• Title, Summary, Keyword: estimation

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Batch Time Interval and Initial State Estimation using GMM-TS for Target Motion Analysis (GMM-TS를 이용한 표적기동분석용 배치구간 및 초기상태 추정 기법)

  • Kim, Woo-Chan;Song, Taek-Lyul
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.3
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    • pp.285-294
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    • 2012
  • Using bearing measurement only, target motion state is not directly obtained so that TMA (Target Motion Analysis) is needed for this situation. TMA is a nonlinear estimation technique used in passive SONAR systems. Also it is the one of important techniques for underwater combat management systems. TMA can be divided to two parts: batch estimation and sequential estimation. It is preferable to use sequential estimation for reducing computational load as well as adaptively to target maneuvers, batch estimation is still required to attain target initial state vector for convergence of sequential estimation. Selection of batch time interval which depends on observability is critical in TMA performance. Batch estimation in general utilizes predetermined batch time interval. In this paper, we propose a new method called the BTIS (Batch Time Interval and Initial State Estimation). The proposed BTIS estimates target initial status and determines the batch time interval sequentially by using a bank of GMM-TS (Gaussian Mixture Measurement-Track Splitting) filters. The performance of the proposal method is verified by a Monte Carlo simulation study.

Hierarchical State Estimation in Power System by Modified Fast Decoupled State Estimation Method and System Decomposition (전력계통에서의 수정고속분할 추정법과 계통분할에 의한 계산적 장웅추정에 관한 연구)

  • 김준현;이종범
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.34 no.5
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    • pp.201-209
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    • 1985
  • This paper describes a method for the state estimation by a modified fast decoupled estimation method and system decomposition. The state values are gained by using the weighted least square estimation method, fast decoupled estimation method, and modified fast decoupled estimation method. The estimated values of each method were compared about effectiveness of state values, respectively. This paper investigated the effects of impedance of well-condition or ill-condition into lines. The characteristics of state estimation were gained through hierarchical state estimation. Each method was applied to three model power systems, and, the results of test for the proposed method are given.

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Estimation of structural vector autoregressive models

  • Lutkepohl, Helmut
    • Communications for Statistical Applications and Methods
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    • v.24 no.5
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    • pp.421-441
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    • 2017
  • In this survey, estimation methods for structural vector autoregressive models are presented in a systematic way. Both frequentist and Bayesian methods are considered. Depending on the model setup and type of restrictions, least squares estimation, instrumental variables estimation, method-of-moments estimation and generalized method-of-moments are considered. The methods are presented in a unified framework that enables a practitioner to find the most suitable estimation method for a given model setup and set of restrictions. It is emphasized that specifying the identifying restrictions such that they are linear restrictions on the structural parameters is helpful. Examples are provided to illustrate alternative model setups, types of restrictions and the most suitable corresponding estimation methods.

Comparison of Parameter Estimation Methods in A Kappa Distribution

  • Park Jeong-Soo;Hwang Young-A
    • Communications for Statistical Applications and Methods
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    • v.12 no.2
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    • pp.285-294
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    • 2005
  • This paper deals with the comparison of parameter estimation methods in a 3-parameter Kappa distribution which is sometimes used in flood frequency analysis. Method of moment estimation(MME), L-moment estimation(L-ME), and maximum likelihood estimation(MLE) are applied to estimate three parameters. The performance of these methods are compared by Monte-carlo simulations. Especially for computing MME and L-ME, three dimensional nonlinear equations are simplified to one dimensional equation which is calculated by the Newton-Raphson iteration under constraint. Based on the criterion of the mean squared error, L-ME (or MME) is recommended to use for small sample size( n$\le$100) while MLE is good for large sample size.

Earthquake Loss Estimation of Buried Pipeline Considering Permanent Ground Deformation due to Liquefaction (액상화.영구지반변형을 고려한 지중매설관로의 지진피해 평가)

  • Kim, Tae-Wook;Lim, Yun-Mook;Kim, Moon-Kyum
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.102-109
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    • 2005
  • In this study, a prototype model of earthquake loss estimation method will be proposed for the quantitative and qualitative damage evaluation of buried pipeline subjected to Permanent Ground Deformation(PGD) due to liquefaction. With this objective, domestic and foreign status of the arts related with earthquake loss estimation method is summarized at first. Domestic development of computer aided earthquake loss estimation method seems to be difficult for the time being. Thus, referring to HAZUS : Earthquake Loss Estimation Methodology which is developed by FEMA (Federal Emergency Management Agency) and NIBS (National Institute of Building Sciences), earthquake loss estimation procedure of buried pipeline subjected to PGD due to liquefaction are proposed, and then exemplary loss estimation are executed. Considering that there have been no practical earthquake loss estimation method and procedure in Korea, the research accomplishments such as above are considered to be helpful for the substantial development of earthquake loss estimation method of buried pipeline subjected to PGD due to liquefaction.

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Adaptive Zoom Motion Estimation Method (적응적 신축 움직임 추정 방법)

  • Jang, Won-Seok;Kwon, Oh-Jun;Kwon, Soon-Kak
    • Journal of Korea Multimedia Society
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    • v.17 no.8
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    • pp.915-922
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    • 2014
  • We propose an adaptive zoom motion estimation method where a picture is divided into two areas based on the distance information with a depth camera : the one is object area and the other is background area. In the proposed method, the zoom motion is only applied to the object area except the background area. Further, the block size of motion estimation for the object area is set to smaller than that of background area. This adaptive zoom motion estimation method can be reduced at the complexity of motion estimation and can be improved at the motion estimation performance by reducing the block size of the object area in comparison with the conventional zoom motion estimation method. Based on the simulation results, the proposed method is compared with the conventional methods in terms of motion estimation accuracy and computational complexity.

The Research of Velocity Estimation Method in Pipe Pumping for Slurry Transportation (슬러리 이송을 위한 관내 유속 추정 방법 연구)

  • Kwon, Seunghee;Jeong, Soonyong;Kim, Yuseung
    • Journal of the Korean Geoenvironmental Society
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    • v.15 no.3
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    • pp.21-32
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    • 2014
  • This Research have suggested the new estimation method using parameter estimation algorithm to substitute established velocity and friction factor calculation equation. Established calculation equation has some difficulties for estimation and reflecting exactly flow specification cause parameter uncertainty and material uncertainty governed real phenomenon, so this research has used system modeling method for flow specification estimation and suggested estimation method.

Noise-Robust Speech Recognition Using Histogram-Based Over-estimation Technique (히스토그램 기반의 과추정 방식을 이용한 잡음에 강인한 음성인식)

  • 권영욱;김형순
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.6
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    • pp.53-61
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    • 2000
  • In the speech recognition under the noisy environments, reducing the mismatch introduced between training and testing environments is an important issue. Spectral subtraction is widely used technique because of its simplicity and relatively good performance in noisy environments. In this paper, we introduce histogram method as a reliable noise estimation approach for spectral subtraction. This method has advantages over the conventional noise estimation methods in that it does not need to detect non-speech intervals and it can estimate the noise spectra even in time-varying noise environments. Even though spectral subtraction is performed using a reliable average noise spectrum by the histogram method, considerable amount of residual noise remains due to the variations of instantaneous noise spectrum about mean. To overcome this limitation, we propose a new over-estimation technique based on distribution characteristics of histogram used for noise estimation. Since the proposed technique decides the degree of over-estimation adaptively according to the measured noise distribution, it has advantages to be few the influence of the SNR variation on the noise levels. According to speaker-independent isolated word recognition experiments in car noise environment under various SNR conditions, the proposed histogram-based over-estimation technique outperforms the conventional over-estimation technique.

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Computer나 Calculator를 이용한 계산에서 오류 교정을 위한 어림셈 지도에 관한 연구

  • Gang Si Jung
    • The Mathematical Education
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    • v.29 no.1
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    • pp.21-34
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    • 1990
  • This is a study on an instruction of estimation for error correction in the calculation with a computer or a calculator. The aim of this study is to survey a new aspect of calaulation teaching and the teaching strategy of estimation and finally to frame a new curriculum model of estimation instruction. This research required a year and the outcomes of the research can be listed as follows: 1. Social utilities of estimation were made clear, and a new trend of calculation teaching related to estimation instruction was shown. 2. The definition of estimation was given and actual examples of conducting an estimation among pupils in lower grades were given for them to have abundant experiences. 3. The ways of finding estimating values in fraction and decimal fraction were presented for the pupils to be able to conduct an estimation. 4. The following contents were given as a basic strategy for estimation. 1) Front-end strategy 2) Clustering strategy 3) Rounding strategy 4) Compatible numbers strategy 5) Special numbers strategy 5. In an instuction of estimation the meaning, method. and process of calculation and calculating algorithm were reviewed for the cultivation of children's creativity through promoting their basic skill, mathematical thinking and problem-solving ability. 6. The following contents were also covered as an estimation strategy for measurement 1) Calculating the sense of quantity on the size of unit. 2) Estimating the total quantity by frequent repetition of unit quantity. 3) Estimating the length and the volume by weighing. 4) Estimating unknown quantity based on the quatity already known. 5) Estimating the area by means of equivalent area transformation. 7. The ways of instructing mental computation were presented. 8. Reviews were made on the curricular and the textbook contents concerning estimation instructions both in Korea and Japan. and a new model of curriculum was devised with reference to estimation instruction data of the United States.

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Teaching and Learning on the Computational Estimation Using Role Play in an Actual Life Problem Situation - Centered on the 3rd Grade - (역할극 중심의 실생활 문제 상황의 어림학습 지도에 관한 연구 - 초등 3학년을 중심으로 -)

  • Kim, Young-Lang;Park, Young-Hee
    • Journal of Educational Research in Mathematics
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    • v.16 no.4
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    • pp.273-295
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    • 2006
  • It is the purpose of this study to help computational estimation study to settle down in effective teaching method through analysis how students are understanding computational estimation and what occurs using computational estimation in actual life problem situations. I set 3 cases to accomplish these purposes. (1) How students are understanding computational estimation? (2) How students' computational estimation ability is in applying actual life problem situation? (3) What is students' different attitudes in an actual life problem situation before studying computational estimation and after? To accomplish tile purpose, I chose 6 third grade students and taught 'Computational estimation using actual life problem situation' and analyzed students computational estimation processing. Then I arranged the computational estimation processing in an actual life problem situation and differences between the before and tile after. As a result, I obtained the followings. (1) Need of estimation: Every students could recognize the need of estimation with experiencing an actual life problem situation. (2) Choosing the order of decimals: Students could choose appropriate order of decimals according to an actual life problem situations. (3) Using strategy: They usually use rounding strategy and quite often use special number and compatible number strategy.

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