• Title/Summary/Keyword: Residuals

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The Abnormal Increasing Pseudorange Satellite Detection Method Using Comparison of Residual Horizontal Projection (잔차 수평 투영 비교를 이용한 의사거리 비정상 증가 위성 식별)

  • Ahn, Yong-Woon;Ahn, Jong-Sun;Won, Dae-Hee;Heo, Mun-Beom;Jo, Jeong-Ho;Sung, Sang-Kyung;Lee, Young-Jae
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.6
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    • pp.570-576
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    • 2010
  • This paper can be used for GPS air navigation study on integrity monitoring algorithm as, the projected horizontal plane using GPS pseudorange residuals for fault detection satellites were suspected. Failure to remove the detected suspicious satellite, compare with threshold which is calculated using satellite deployment (PDOP) and determine whether the failure is presented. The theory that horizontal projection of the satellite failure residuals greater than residual of normal satellite is proved mathematically. Comparison with horizontal projection residuals are likely to malfunction in the satellite were presented. To evaluate the proposed algorithm, bias fault insert into GPS pseudorange, and compare with conventional parity space method about fault detection and isolation capability.

A CUSUM Chart for Detecting Mean Shifts of Oscillating Pattern (진동 패턴의 평균 변화 탐지를 위한 누적합 관리도)

  • Lee, Jae-June;Kim, Duk-Rae;Lee, Jong-Seon
    • The Korean Journal of Applied Statistics
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    • v.22 no.6
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    • pp.1191-1201
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    • 2009
  • The cumulative sum(CUSUM) control charts are typically used for detecting small level shifts in process control. To control an auto-correlated process, the model-based control methods can be employed, in which the residuals from fitting a time series model are applied to the CUSUM chart. However, the persistent level shifts in the original process may lead to varying mean shifts in residuals, which may deteriorate detection performance significantly. Therefore, in this paper, focussing on ARMA(1,1), we propose a new CUSUM type control method which can detect the dynamic mean shifts in residuals especially with oscillating pattern effectively and, through the simulation study, evaluate its performance by comparing with other various CUSUM type control methods introduced so far.

Statistical Analysis on Residuals from No-Fault Reference Models of a Residential Heat Pump System in Normal Cooling Operation (가정용 열펌프 시스템의 정상냉방 운전조건에서 기준모델에 의한 잔차의 통계적 분석)

  • Kim, Min-Sung;Yoon, Seok-Ho;Baik, Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.12
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    • pp.1351-1358
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    • 2011
  • To approximate the threshold of the fault detection and diagnosis (FDD) system, validation of the measurements is mandatory. Naturally, the system shows uncertainties due to measuring sensors - mostly thermocouples or RTDs - and due to repeatability. The uncertainty of a thermocouple comes from natural variation or a drift of the thermocouple measurement. Considering the natural variation behaves like zero-mean white noise, its natural variation can be characterized closely by the steady-state standard deviation. However, residuals between measurements and no-fault references in FDD systems show a statistical distribution with various uncertainties. In this paper, steady-state variations of measurement residuals were investigated by utilizing built-in temperature sensors in a heat pump for the model development and the final application.

Sequential Extraction of Heavy Metals in Soils and A Case Study (토양중의 중금속 연속추출방법과 사례연구)

  • Jung, Myung Chae
    • Economic and Environmental Geology
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    • v.27 no.5
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    • pp.469-477
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    • 1994
  • Many researchers have investigated most representative sequential extraction method using various reagents for determining the chemical forms of metals in soils and sediments. In this paper, a newly modified method for sequential extraction scheme based on Tessier's method by Environmental Geochemistry Research, Centre for Environmental Technology, Imperial College, was introduced and examined. In comparison with Tessier's method, originally designed for sediment analysis by Atomic Absorption Spectrophotometry (AAS), the sequential extraction scheme has been developed for the multi-element analysis by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The partitioning of particulate trace elements was classified into five fractions: (i) exchangeable, (ii) bound to carbonates or specially adsorbed, (iii) bound to Fe and Mn oxides, (iv) bound to organic matter and sulphides and (v) residuals. The experimental results of the pilot study for in-house reference material (HRM2) and certified international standard reference material (SRM2711) using the modified method showed not only reasonable precision and accuracy but also acceptable overall recovery rates. In addition, mine dump soils sampled in the Dalsung Cu-W mine, Korea were prepared and sequentially extracted using the method. Most of Cu was bound to organic matter/sulphides and residual fractions. The dominant fraction of soil Pb and Zn in the study area was found in the residuals. The fraction of Cd showed a wide variation between samples and could be found bound to the carbonates or specially adsorbed, oxides, organic fraction and residuals. The recovery rates of Cd, however, were poor due to relatively low Cd concentrations in soils. The heavy metals in these mine dumps appear to be in the more inert forms and should not be readily bioavailable. The soils, however, had very low pH values (average 4.1) and had sandy textures; consequently, rapid infiltration of rainfall may increase leaching of Zn and Cd which were found to be around 5 to 10% of the exchangeable fraction. As a result of the investigation of this study, it has been strongly recommended that these mine waste materials should still be considered a significant contaminant source and will need environmental remediation to prevent pollutants from being released into the environment.

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Comparison of Solar Power Generation Forecasting Performance in Daejeon and Busan Based on Preprocessing Methods and Artificial Intelligence Techniques: Using Meteorological Observation and Forecast Data (전처리 방법과 인공지능 모델 차이에 따른 대전과 부산의 태양광 발전량 예측성능 비교: 기상관측자료와 예보자료를 이용하여)

  • Chae-Yeon Shim;Gyeong-Min Baek;Hyun-Su Park;Jong-Yeon Park
    • Atmosphere
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    • v.34 no.2
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    • pp.177-185
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    • 2024
  • As increasing global interest in renewable energy due to the ongoing climate crisis, there is a growing need for efficient technologies to manage such resources. This study focuses on the predictive skill of daily solar power generation using weather observation and forecast data. Meteorological data from the Korea Meteorological Administration and solar power generation data from the Korea Power Exchange were utilized for the period from January 2017 to May 2023, considering both inland (Daejeon) and coastal (Busan) regions. Temperature, wind speed, relative humidity, and precipitation were selected as relevant meteorological variables for solar power prediction. All data was preprocessed by removing their systematic components to use only their residuals and the residual of solar data were further processed with weighted adjustments for homoscedasticity. Four models, MLR (Multiple Linear Regression), RF (Random Forest), DNN (Deep Neural Network), and RNN (Recurrent Neural Network), were employed for solar power prediction and their performances were evaluated based on predicted values utilizing observed meteorological data (used as a reference), 1-day-ahead forecast data (referred to as fore1), and 2-day-ahead forecast data (fore2). DNN-based prediction model exhibits superior performance in both regions, with RNN performing the least effectively. However, MLR and RF demonstrate competitive performance comparable to DNN. The disparities in the performance of the four different models are less pronounced than anticipated, underscoring the pivotal role of fitting models using residuals. This emphasizes that the utilized preprocessing approach, specifically leveraging residuals, is poised to play a crucial role in the future of solar power generation forecasting.

Evaluation of a new method, "non-injection resection using bipolar soft coagulation mode (NIRBS)", for colonic adenomatous lesions

  • Mitsuo Tokuhara;Masaaki Shimatani;Kazunari Tominaga;Hiroko Nakahira;Takuya Ohtsu;Katsuyasu Kouda;Makoto Naganuma
    • Clinical Endoscopy
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    • v.56 no.5
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    • pp.623-632
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    • 2023
  • Background/Aims: Endoscopic resection of all colorectal adenomatous lesions with a low complication rate, simplicity, and negative residuals is challenging. Hence, we developed a new method called "non-injection resection using bipolar soft coagulation mode (NIRBS)" method, adapted for colorectal lesions. In addition, we evaluated the effectiveness of this method. Methods: We performed NIRBS throughout a 12-month period for all colorectal lesions which snare resection was acceptable without cancerous lesions infiltrating deeper than the submucosal layer. Results: A total of 746 resected lesions were included in the study, with a 4.5 mm mean size (range, 1-35 mm). The major pathological breakdowns were as follows: 64.3% (480/746) were adenomas, and 5.0% (37/746) were intraepithelial adenocarcinomas (Tis lesions). No residuals were observed in any of the 37 Tis lesions (mean size, 15.3 mm). Adverse events included bleeding (0.4%) but no perforation. Conclusions: NIRBS allowed the resection of multiple lesions with simplicity because of the non-injection and without perforating due to the minimal burn effect of the bipolar snare set in the soft coagulation mode. Therefore, NIRBS can be used to resect adenomatous lesions easily, including Tis lesions, from small to large lesions without leaving residuals.

Characteristic Analysis of the Tidal Residuals' Mid/Long-period Components Using a Wavelet Method (웨이블릿방법을 이용한 조위편차 성분의 중·장주기 특성 분석)

  • Kang, Ju Whan;Kim, Yang-Seon;Shim, Jae-Seol
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.25 no.4
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    • pp.200-206
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    • 2013
  • Fourier analysis and a wavelet method were carried out to elucidate the characteristics of tidal residual components in coastal waters. The result of Fourier analysis shows tide-induced and monsoon-induced residuals are conspicuous at the short period and mid period, respectively. The tidal residuals were decomposed by period from 3 hours to 8 months and the characteristics of their components were shown by reconstituting them with short periods less than 24 hours, mid-periods between 1 day and 16 days and long periods longer than 1 month. The tidal residuals in the short period, i.e., tide-induced components, being based on the tidal elevation prediction errors, appear in the West Sea with high tidal ranges and do not have much seasonal fluctuation. Additionally, the period of typhoon induced surge ranges more or less than 12 hours. The mid-period components were clearly generated mainly in the West Sea during the winter and largely affected by monsoon. Accordingly, the pure surge height components were concentrated on the mid-period and had clear features for each coastal waters. The long period components show similar characteristics at all stations and are considered to stem from variations of mean sea levels.

A Study on the Least Squared Estimator of Autoregressive Models when Consecutive Missing Observations Exist

  • Ryu, Gui-Yeol
    • Communications for Statistical Applications and Methods
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    • v.3 no.3
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    • pp.59-74
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    • 1996
  • The properties of the residuals are investigated when K-consecutive observations are interpolated. The central limit theorem is also proved for the LSE for autoregressive parameters when $\kappa4--consecutive observations are contaminated. The performance of the interpolated LSE in small samples is investigated by simulation. And the interpolated with the Yule-Walker type estimator.

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