• 제목/요약/키워드: curve fitting

검색결과 815건 처리시간 0.025초

다중영상해석에 의한 전파망원경의 3차원 정밀측정 (The Exact Position Measurement of Radio Telescope by Multi-photo Analysis)

  • 강준묵;한승희;엄대용;이주대
    • 한국측량학회지
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    • 제20권3호
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    • pp.243-253
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    • 2002
  • 최근 들어 수치사진측량은 산업분야를 비롯한 여러 분야에 그 활용범위가 확대되면서 측정정확도의 향상을 위한 다각적인 연구가 진행되고 있으며 그중 다중영상을 이용한 해석방법은 많은 연구자들로 하여금 관심을 모으고 있다. 그러나 이 방법은 영상획득의 용이성과 높은 해석정확도의 확보가 가능한 반면 처리데이터양의 증가로 많은 처리시간과 노력을 요하게 되므로 처리과정의 자동화를 통한 작업의 효율성 향상을 기하여야 한다. 이에 본 연구에서는 정밀시공이 요구되는 전파망원경에 대해 다중영상을 획득하여 이를 해석하기 위한 영상해석과정의 자동화를 구현하고 대상물에 대한 정밀 측정 및 정확도 향상을 꾀하고자 하였다. 연구결과 정밀한 측정을 요하는 대상물에 대해 다중영상해석을 통한 정확도 향상을 도모할 수 있었으며 이를 토대로 전파망원경의 정밀 측정 및 곡률산출을 수행하여 대상물의 시공 후 조립정확도를 검사할 수 있었다.

Oxytetracycline의 약욕 및 경구투여에 따른 넙치(Paralichthys olivaceus) 체내 약물동태학적 특성 (Pharmacokinetics of oxytetracycline in olive flounder (Paralichthys olivaceus) by dipping and oral administration)

  • 정승희;최동림;김진우;조미라;서정수;지보영
    • 한국어병학회지
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    • 제21권2호
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    • pp.107-117
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    • 2008
  • The pharmacokinetic properties of oxytetracycline (OTC) were studied after dipping and oral administration to cultured olive flounder, Paralichthys olivaceus (600 g). Plasma concentrations of OTC were determined after oral dosage (50, 100 and 200 mg/kg body weight) and dipping (50, 100 and 200 ppm, 1 h) in olive flounder (average 600 g, 23±1℃). Plasma samples were taken at 3, 5, 10, 15, 24, 32, 48, 72, 120, 168 and 240 h post-dose. In oral dosage of 50, 100 and 200 mg/kg, the peak plasma concentrations of OTC, which attained at 3 h post-dose, were 0.34, 0.44 and 1.18 ㎍/㎖, respectively. In dipping of 50, 100 and 200 ppm, those of OTC which also observed at 5 h post-dose, were 0.43, 0.38 and 0.64 ㎍/㎖, respectively. Plasma concentrations of OTC were not measurable at 240 h post-dose in all experiments. The kinetic profile of absorption, distribution and elimination of OTC in plasma were analyzed fitting to a one-compartment model by WinNonlin program. The following parameters were calculated for a single dosage of 50, 100 and 200 mg/kg body weight, respectively: AUC (the area under the concentration-time curve)=31.40, 28.07 and 32.97 ㎍∙h/㎖; T1/2 (half-life)􀆫0.89, 1.12 and 0.43 h; Tmax (time for maximum concentration)= 5.25, 3.70 and 7.30 h, Cmax (maximum concentration)=0.25, 0.38 and 0.61 ㎕/㎖. Following dipping at 50, 100 and 200 ppm, these parameters were AUC􀆫15.51, 14.63 and 19.72 ㎍∙h/㎖; T1/2= 0.75, 0.41 and 0.74 h; Tmax=4.90, 7.08 and 4.68 h, Cmax=0.40, 0.32 and 0.46 ㎕/㎖.

경계(警戒) 임무(任務) 담당자(擔當者)의 시간지연(時間遲延)에 따르는 인간(人間) 성능(性能)의 변화(變化)에 대(對)한 연구(硏究) 및 개선방안(改善方案) (The Human Performance Degradation in Vigilance due to Prolonged and Monotonous Tasks)

  • 이면우
    • 대한조선학회지
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    • 제11권1호
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    • pp.27-34
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    • 1974
  • This study is aimed at a validation of the vigilance simulation model which was proposed earlier (2). The model estimates a perceived danger value, an alertness level and the probability of detection at a given elapsed time of vigilance. Twenty-nine male and seven female subjects were given a simple task. They were asked to detect a number(four numbers out of six digits in the telephone directory which have the probability of occurrence in the range of 0.0010-0.0018) in six different experimental conditions, for periods of two to three hours. Analysis of the experiments showed that although the mean detection rate varied slightly in two hours, the within-subject variance and the number of cyclic performance fluctuations increased significantly. A primal factor that affects the performance seems to be the frequency of target occurrence. By curve fitting, the relation between the probability of detection and the percentages of danger event occurrence was derived; $y=0.50(1-{\varepsilon}^{-50x^2})+0.39$. Assuming the equation represents the normal detection rate(100% performance), the Relative Vigilance Performance Rating was calculated. This rating method could be a useful criterion in selecting and training of the vigilance personnel. The results show that the simulation model is a good estimator of human a performance when the probability of danger occurrence is greater than 0.0015; it gives a good reference for improving the vigilance system. Suggestions are made that (1) the validity of proposed functional equations over the extended range of danger probability be studied, (2) an analysis of the cyclic fluctuations of the alertness level be accomplished, and (3) the cost functions of detection reliability be included in any future model.

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Forecasting of the COVID-19 pandemic situation of Korea

  • Goo, Taewan;Apio, Catherine;Heo, Gyujin;Lee, Doeun;Lee, Jong Hyeok;Lim, Jisun;Han, Kyulhee;Park, Taesung
    • Genomics & Informatics
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    • 제19권1호
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    • pp.11.1-11.8
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    • 2021
  • For the novel coronavirus disease 2019 (COVID-19), predictive modeling, in the literature, uses broadly susceptible exposed infected recoverd (SEIR)/SIR, agent-based, curve-fitting models. Governments and legislative bodies rely on insights from prediction models to suggest new policies and to assess the effectiveness of enforced policies. Therefore, access to accurate outbreak prediction models is essential to obtain insights into the likely spread and consequences of infectious diseases. The objective of this study is to predict the future COVID-19 situation of Korea. Here, we employed 5 models for this analysis; SEIR, local linear regression (LLR), negative binomial (NB) regression, segment Poisson, deep-learning based long short-term memory models (LSTM) and tree based gradient boosting machine (GBM). After prediction, model performance comparison was evelauated using relative mean squared errors (RMSE) for two sets of train (January 20, 2020-December 31, 2020 and January 20, 2020-January 31, 2021) and testing data (January 1, 2021-February 28, 2021 and February 1, 2021-February 28, 2021) . Except for segmented Poisson model, the other models predicted a decline in the daily confirmed cases in the country for the coming future. RMSE values' comparison showed that LLR, GBM, SEIR, NB, and LSTM respectively, performed well in the forecasting of the pandemic situation of the country. A good understanding of the epidemic dynamics would greatly enhance the control and prevention of COVID-19 and other infectious diseases. Therefore, with increasing daily confirmed cases since this year, these results could help in the pandemic response by informing decisions about planning, resource allocation, and decision concerning social distancing policies.

Mechanical performance of sand-lightweight concrete-filled steel tube stub column under axial compression

  • Zhang, Xianggang;Deng, Dapeng;Lin, Xinyan;Yang, Jianhui;Fu, Lei
    • Structural Engineering and Mechanics
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    • 제69권6호
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    • pp.627-635
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    • 2019
  • In order to study the axial compression performance of sand-lightweight concrete-filled steel tube (SLCFST) stub columns, three circular SLCFST (C-SLCFST) stub column specimens and three SLCFST square (S-SLCFST) stub column specimens were fabricated and static monotonic axial compression performance testing was carried out, using the volume ratio between river sand and ceramic sand in sand-lightweight concrete (SLC) as a varying parameter. The stress process and failure mode of the specimens were observed, stress-strain curves were obtained and analysed for the specimens, and the ultimate bearing capacity of SLCFST stub column specimens was calculated based on unified strength theory, limit equilibrium theory and superposition theory. The results show that the outer steel tubes of SLCFST stub columns buckled outward, core SLC was crushed, and the damage to the upper parts of the S-SLCFST stub columns was more serious than for C-SLCFST stub columns. Three stages can be identified in the stress-strain curves of SLCFST stub columns: an elastic stage, an elastic-plastic stage and a plastic stage. It is suggested that AIJ-1997, CECS 159:2004 or AIJ-1997, based on superposition theory, can be used to design the ultimate bearing capacity under axial compression for C-SLCFST and S-SLCFST stub columns; for varying replacement ratios of natural river sand, the calculated stress-strain curves for SLCFST stub columns under axial compression show good fitting to the test measure curves.

Single-Shot LiDAR system을 이용한 Timing Jitter 분석 및 개선 방안 (Timing Jitter Analysis and Improvement Method using Single-Shot LiDAR system)

  • 한문현;최규동;송민협;서홍석;민봉기
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2016년도 추계학술대회
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    • pp.172-175
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    • 2016
  • 시간 정보를 이용하여 거리 측정 및 물체 탐지 등에 사용되고 있는 Time of Flight(ToF) LiDAR(Light Detection And Ranging) 기술이 자율 주행 자동차, 지형 분석 같이 보다 정밀 측정이 필요한 분야에 응용되면서 ToF 시간 정보 추출에 대한 중요성이 높아지고 있다. 본 논문에서는 ToF 시간 정보의 정확성의 지표로 timing jitter를 사용하였고, 약 31M free space 환경에서 1.5um 파장의 MOPA LASER와 InGaAs Avalanche Photodiode(APD)로 이루어진 Single-Shot LiDAR system(SSLs)을 통해 측정 및 분석하였다. 또한 SSLs를 통해 측정된 데이터에 curve fitting 방법인 spline interpolation과 반복 측정된 피크 데이터를 이용하는 multiple-shot averaging 방법을 적용하여 timing jitter 개선결과를 제시하였다.

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남성 정장 수트의 시각적 이미지에 관한 연구 (A study on the visual image of men's suit)

  • 김정미
    • 한국의상디자인학회지
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    • 제23권1호
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    • pp.113-127
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    • 2021
  • This study aims to analyze the style of men's suits and extract expressional words for the development of semantic differential scales of visual images according to the change in silhouette. Research methods are literature studies, case studies, and questionnaires. The stimuli were created using CLO 3D, a virtual sewing CAD. This study's results are as follows: 1) The British suit jacket has an angled shoulder line using thin pads, and a slightly higher waistline. The pants of the suit have a high waistline and two pleats, so the thighs of the pants are wide. The American suit jacket has a natural shoulder line, and the waistline is not emphasized. The width of the jacket is relaxed, and the length is long. The pants of the suit have a higher waistline, and the pants are wide as well. The Italian suit jacket has wide shoulders, and the waistline is connected lower with a soft curve, and the length is relatively short. The trousers of the suit are tapered and get narrower as it goes down to the hem. 2) Because it originated in the practices of true bespoke tailoring, traditional British suits have a far more 'fitted' silhouette than the mass-produced styles that became emblematic of the American style. By the late 1950s, a sack-style suit was standard American business attire. This technique gives the sack suit its characteristically 'boxy' silhouette. The "Continental" presented a highly tailored silhouette, with padded shoulders, a slim, tight-fitting chest, and a closely tapered waist. The story was that Italian culture valued aesthetics over all else and thus sought the 'slim' suit style as much as possible. 3) The main expressional words of visual images for men's suits differ greatly depending on the silhouette of suit. The visual images are ranked in the order of 'neat', 'classic', 'educated', 'hard', 'mature', for fitted silhouettes. The words of 'masculine', 'basic', 'comfortable', 'simple', 'mature', 'conservative', 'modern', are ranked for boxy silhouettes. And the words of 'slim', 'young', 'neat', are noted for slim silhouettes.

기하 위상 렌즈 기반의 색공초점 센서를 이용한 투명 물질 두께 측정 연구 (Transparent Plate Thickness Measurement Approach Using a Chromatic Confocal Sensor Based on a Geometric Phase Lens)

  • 송민관;박효미;주기남
    • 한국광학회지
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    • 제33권6호
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    • pp.317-323
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    • 2022
  • 본 논문에서는 투명한 물질의 두께를 측정하기 위한 방법으로 기하 위상 렌즈 기반의 색공초점 센서를 개발하고, 성능 개선을 위한 보정 방법을 제시한다. 일반적인 색공초점 센서의 복잡한 설계로 인한 한계를 극복하기 위해, 기하 위상 렌즈를 이용하여 전체 시스템의 크기를 줄이고, 시스템 오차를 보상하기 위한 파장 첨두 위치 추출 방법과 계통 오차 제거 방법을 설명한다. 색공초점 센서를 이용하여 투명한 물질의 두께를 측정하기 위한 이론을 설명하고, 이를 사파이어 및 BK7 물질의 두께를 측정함으로써 실험적으로 검증한다. 색공초점 센서를 이용한 두께 측정 방법은 기존의 간섭계 및 공초점 센서의 방법들에 비해 측정 속도가 빠르고, 분산 등에 의한 두께 측정 영역 제한이 없기 때문에 많은 응용이 가능하다.

심장 치료 전후의 혈압 측정 인자의 변화에 관한 연구 (A Study on the Changes of Blood Pressure Measurement Factors Before and After Heart Treatment)

  • 최원석
    • 융합신호처리학회논문지
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    • 제22권2호
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    • pp.51-56
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    • 2021
  • 상완 수축기 혈압과 맥압은 50세 이상의 개인에서 심혈관 질환의 예측 인자이다. 강성이 증가함에 따라 수축기 후기의 반사 진폭과 압력이 증가하여 좌심실 부하와 심근 산소 요구량이 증가한다. 따라서 강성이 혈압에 미치는 영향을 연구 할 필요가 있다. 본 연구에서는 약물 복용 전후에 혈압 맥파를 측정하고, 심부전 환자에서 심근 심장 이식 전후에 혈압 맥파를 측정하였다. Windkessel 모델의 R, L 및 C 구성 요소 간의 상관관계는 혈압을 높임으로써 추정되었다. 커브 피팅 방법을 사용하여 Windkessel 모델의 매개 변수를 모델링 한 결과 혈압의 증가와 수축기 상승 시간의 감소는 RLC Windkessel 모델의 L 성분이 증가했기 때문이다. 혈관의 다양한 기계적 특성 중에 높은 BP 파형에 영향을 미치는 가장 중요한 매개 변수는 실험결과로 이너턴스인 것을 증명하였다.

Lactation milk yield prediction in primiparous cows on a farm using the seasonal auto-regressive integrated moving average model, nonlinear autoregressive exogenous artificial neural networks and Wood's model

  • Grzesiak, Wilhelm;Zaborski, Daniel;Szatkowska, Iwona;Krolaczyk, Katarzyna
    • Animal Bioscience
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    • 제34권4호
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    • pp.770-782
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    • 2021
  • Objective: The aim of the present study was to compare the effectiveness of three approaches (the seasonal auto-regressive integrated moving average [SARIMA] model, the nonlinear autoregressive exogenous [NARX] artificial neural networks and Wood's model) to the prediction of milk yield during lactation. Methods: The dataset comprised monthly test-day records from 965 Polish Holstein-Friesian Black-and-White primiparous cows. The milk yields from cows in their first lactation (from 5 to 305 days in milk) were used. Each lactation was divided into ten lactation stages of approximately 30 days. Two age groups and four calving seasons were distinguished. The records collected between 2009 and 2015 were used for model fitting and those from 2016 for the verification of predictive performance. Results: No significant differences between the predicted and the real values were found. The predictions generated by SARIMA were slightly more accurate, although they did not differ significantly from those produced by the NARX and Wood's models. SARIMA had a slightly better performance, especially in the initial periods, whereas the NARX and Wood's models in the later ones. Conclusion: The use of SARIMA was more time-consuming than that of NARX and Wood's model. The application of the SARIMA, NARX and Wood's models (after their implementation in a user-friendly software) may allow farmers to estimate milk yield of cows that begin production for the first time.