• Title/Summary/Keyword: error equation

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Evaluation of Ballistic Resistance Performance by Thickness and Proportion of Magnetic Aggregate of Concrete (콘크리트 두께와 자철광 함량에 따른 방탄 성능 평가)

  • Lim, Cha-Yeon;Kim, Kuk-Joo;Roh, Jeong-Heon;Jang, Chang-Su;Park, Young-Jun
    • Journal of the Korea Institute of Building Construction
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    • v.20 no.1
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    • pp.43-51
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    • 2020
  • The main purpose of protective facility for small military unit is to provide the protection of not all the weapons system but the near-miss bullet in Korean army. In particular about the small caliber bullets, especially KM80 in Korea, there were many studies that both of the experiential and structural design methods dose not reflect enough the military threat. For that reason, a new equation to calculate effective anti-piercing depths for RC slabs against small caliber bullets is proposed in earlier research with actual shooting test. But, the test only considers the strength of concrete without the thickness of concrete, types of aggregate, the angle of yaw of bullet, high-strength concrete, etc. Therefore, this study evaluated the ballistic resistance performance by thickness and proportion of magnetic aggregate of concrete. As a result, we identified two major statistical estimations that the error of piercing depth by the angle of yaw of bullet could be cancelled by barrage and the thickness and proportion of magnetic aggregate of concrete dose not effect on the protection ability of concrete structure.

Growth curve estimates for wither height, hip height, and body length of Hanwoo steers (Bos taurus coreanae)

  • Park, Hu-Rak;Eum, Seung-Hoon;Roh, Seung-Hee;Sun, Du-Won;Seo, Jakyeom;Cho, Seong-Keun;Lee, Jung-Gyu;Kim, Byeong-Woo
    • Korean Journal of Agricultural Science
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    • v.44 no.3
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    • pp.384-391
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    • 2017
  • Growth curves in Hanwoo steers were estimated by Gompertz, Von Bertalanffy, Logistic, and Brody nonlinear models using growth data collected by the Hanwoo Improvement Center from a total of 6,973 Hanwoo (Bos taurus coreanae) steers 6 to 24 months old that were born between 1996 and 2015. The data included three parameters: A, mature size of body measurement; b, growth ratio; and, k, intrinsic growth rate. Nonlinear regression equations for wither height according to Gompertz, Von Bertalanffy, Logistic, and Brody models were $Y_t=144.7e^{-0.5869e^{-0.00301t}}$, $Y_t=145.3(1-0.1816e^{-0.00284t})^3$, $Y_t=143.1(1+0.7356e^{-0.00352t})^{-1}$, and $Y_t=146.8(1+0.4700e^{-0.00249t})^1$, respectively, while those for hip height were $Y_t=144.5e^{-0.5549e^{-0.00312t}}$, $Y_t=145.0(1-0.1724e^{-0.00295t})^3$, $Y_t=143.1(1+0.6863e^{-0.00360t})^{-1}$, and $Y_t=146.2(1+0.4501e^{-0.00263t})^1$, respectively. Equations for body length $Y_t=174.1e^{-0.8342e^{-0.00289t}}$, $Y_t=175.8(1-0.2500e^{-0.00265t})^3$, $Y_t=170.0(1+1.1548e^{-0.00363t})^{-1}$, and $Y_t=180.3(1+0.6077e^{-0.00215t})^1$, respectively, for the same models. Among the four models, the Brody model resulted in the lowest mean square error, with mean square errors of 31.79, 30.57, and 42.13, respectively, for wither height, hip height, and body length. Also, an estimated birth wither height, birth hip height, and birth body length (77.98, 80.57, and 70.97 cm, respectively) were lower in the Brody model than in other models. An inflection point was not observed during the growth phase of Hanwoo steer according to the growth curves calculated using Gompertz, Von Bertalanffy, and Logistic models. Based on the results, we concluded that the regression equation using the Brody model was the most appropriate among the four growth models. To obtain more accurate parameters, however, using data from a wider production period (from birth to shipping) would be required, and the development of a suitable model for body conformation traits would be needed.

Estimation of Energy Expenditure using Unfixed Accelerometer during Exercise (비고정식 가속도계를 이용한 운동 중 에너지소비 추정)

  • Kim, Joo-Han;Lee, Jeon;Lee, Hee-Young;Kim, Young-Ho;Lee, Kyoung-Joung
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.48 no.4
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    • pp.63-70
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    • 2011
  • In this paper, we proposed a method for estimating energy expenditure using the unfixed axis of the accelerometer. Most studies adopted waist-placement because of the fact that the waist is close to the center of mass of a whole human body. But we adopted pocket-placement, which is capable of using unfixed axis of sensor, that is more convenient than conventional methods. To evaluate the proposed method, 28 male subjects performed walking and running on a motor driven treadmill. All of subject put on the indirect calorimeter and fixed accelerometer, then data were simultaneously measured during exercise. The regression analysis was performed using the test group(n=20) and the regression equation was applied to the control group(n=8). A strong linear relationship between energy expenditure and unfixed accelerometer signal was found. Futhermore, the coefficient of determination was significantly reliable($R^2$=0.98) and showed zero of p-value. The error of energy expenditure estimation between indirect calorimeter and two types of accelerometer was 15.0%(fixed) and 17.0%(unfixed) respectively. These results show the possibilities that the unfixed accelerometer can be used in estimating the energy expenditure during exercise.

Estimation of Volume-Area-Depth Relationship for Shallow Wetland (습지의 체적-면적-깊이에 대한 관계식 추정)

  • Kim, Jun-Gwon;Kim, Hyeong-Su;Jeong, Sang-Man
    • Journal of Korea Water Resources Association
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    • v.35 no.2
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    • pp.231-240
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    • 2002
  • The wetland has very important functions in hydrologic and ecological aspects and the research of wetland functions requires the basic hydrological properties such as water quantity. However, we do not have a research work on the hydrological properties for a wetland study in Korea. Therefore, this study is to estimate the relations between the volume(V), the area(A), and the depth(h) of water in the wetland which might be the basis for the wetland research in Korea. To estimate the relations, we derive the basic equations, obtain the surveyed data and do modelling, and estimate the relations of A-h and V-h using the Surfer program. The estimated and observed volumes for 5-wetland are compared and the errors are in the range of 2 % to 11 % for 4-wetland and 34 % for the rest. The wetlands in small errors showed the similar ones with the profile of the wetted perimeter which is assumed for the derivation of the equation but the wetland of large error has much different profile with the assumed one. We re-estimate the volumes for 3-wetland(W3, W4, W5) which showed the large errors due to the bended profiles of the wetland slopes. say, after the slopes was divided into two parts of upper and lower ones, the volumes were estimated. From our re-estimation, we obtained very good results ranged from 1 % to 8 % in their errors. We conjecture that the procedure suggested in this study might be useful as a reference for the future research on the relations of V-A-h in Korea.

Estimating Forest Site Productivity and Productive Areas of Quercus acutissima and Quercus mongolica Using Environmental Variables (환경요인에 의한 상수리나무와 신갈나무의 임지생산력 및 적지 추정)

  • Shin, Man-Yong;Sung, Joo-Han;Chun, Jung-Hwa
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.14 no.2
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    • pp.89-97
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    • 2012
  • This study was conducted to estimate forest site productivity and productive areas of Quercus acutissima and Quercus mongolica using environmental factors including climatic variables. Using the data set from digital forest site map and forest climatic map, a total of 42 environmental variables were regressed on site index for developing the best site index equations for Quercus acutissima and Quercus mongolica. Five to six environmental factors by species were selected as independent variables in the best site index equations. For the site index equations, three evaluation statistics (i.e., mean difference, standard deviation of difference, and standard error of difference) were applied to the test data set for the validation of the results, The site index equations fitted well to the test data set with relatively low bias and variation. As a result, it was concluded that the site index equations by species were well capable of estimating site quality. Finally, based on the site index equations, the productive areas by species were estimated by applying GIS technique to the digital forest maps. In addition, the distribution of productive areas by species was illustrated.

Development of Scour Depth Calculation Equation Based on Hydraulic Model Test Data (수리모형실험 자료를 활용한 교각세굴심 산정식의 개발)

  • Chang, Hyung-Joon;Lee, Ho Jin;Lee, Hyo Sang;Kim, Sung-Duk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.1
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    • pp.163-168
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    • 2020
  • Since the industrialization in the 1960s, Korea has been expanding its transportation infrastructure, such as building bridges. Owing to bridge construction, studies on stability review have been carried out, and stability-securing technology has been developed. On the other hand, these were applied mainly to the upper part of the bridge, so applications to the lower part are limited. In particular, scour at the bridge pier causes erosion in the riverbed and bridge collapse. Hence, prevention studies and countermeasures are needed. In this study, an empirical formula was developed to evaluate the scour depth of a bridge, which was calculated through multiple linear regression analysis using the hydraulic model study data conducted in previous studies. The formula, which had a value of 0.91, was applied to the model test data that was not used for development to verify the developed formula. When the pier scour depths were compared in 23 cases, the error rate was less than 20% in 16 cases (70%). The empirical formula developed in this study is applicable to pier scour-depth calculations. Further research will be needed to develop a more accurate empirical formula for pier scour-depth calculations, and it is expected to reduce bridge damage caused by scour.

Evaluation of Cable Impact Factor by Moving Vehicle Load Analysis in Steel Composite Cable-Stayed Bridges (차량 이동하중 해석에 의한 강합성 사장교 케이블의 충격계수 평가)

  • Park, Yong-Myung;Park, Jae-Bong;Kim, Dong-Hyun;Choi, Byung-Ho
    • Journal of Korean Society of Steel Construction
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    • v.23 no.2
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    • pp.199-210
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    • 2011
  • The cables in cable-stayed bridges are under high stress and are very sensitive to vibration due to their small section areas compared with other members. Therefore, it is reasonable to evaluate the cable impact factor by taking into account the dynamic effect due to moving-vehicle motion. In this study, the cable impact factors were evaluated via moving-vehicle-load analysis, considering the design parameters, i.e., vehicle weight, cable model, road surface roughness, vehicle speed, longitudinal distance between vehicles. For this purpose, two steel composite cable-stayed bridges with 230- and 540-m main spans were selected. The results of the analysis were then compared with those of the influence line method that is currently being used in design practice. The road surface roughness was randomly generated based on ISO 8608, and the convergence of impact factors according to the number of generated road surfaces was evaluated to improve the reliability of the results. A9-d.o.f. tractor-trailer vehicle was used, and the vehicle motion was derived from Lagrange's equation. 3D finite element models for the selected cable-stayed bridges were constructed with truss elements having equivalent moduli for the cables, and with beam elements for the girders and the pylons. The direct integration method was used for the analysis of the bridge-vehicle interaction, and the analysis was conducted iteratively until the displacement error rate of the bridge was within the specified tolerance. It was acknowledged that the influence line method, which cannot consider the dynamic effect due to moving-vehicle motion, could underestimate the impact factors of the end-cables at the side spans, unlike moving-vehicle-load analysis.

The Study on Empirical Propagation Path Loss Model in the Antler Terminal Environment (엔틀러 터미널 환경에서 실험적인 패스 로스 모델에 관한 연구)

  • Kim, Kyung-Tae;Kim, Jin-Wook;Jo, Yun-Hyun;Kim, Sang-Uk;Yoon, In-Seop;Park, Hyo-Dal
    • Journal of Advanced Navigation Technology
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    • v.17 no.5
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    • pp.516-523
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    • 2013
  • In this paper, The path loss model of Air Traffic Control(ATC) telecommunication radio channel has been studied at the Incheon International Airport(IIA) with the terminal with two antlers. We measured two frequencies among VHF/UHF channel bands. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponents at passager terminal areas were 3.32 and 3.10 respectively in 128.2 MHz and 269.1 MHz. The deviation of prediction error is 9.69 and 9.65. The new path loss equation at the terminal area was also developed using the derived path loss parameters. The new path loss was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

Broadband Processing of Conventional Marine Seismic Data Through Source and Receiver Deghosting in Frequency-Ray Parameter Domain (주파수-파선변수 영역에서 음원 및 수신기 고스트 제거를 통한 전통적인 해양 탄성파 자료의 광대역 자료처리)

  • Kim, Su-min;Koo, Nam-Hyung;Lee, Ho-Young
    • Geophysics and Geophysical Exploration
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    • v.19 no.4
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    • pp.220-227
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    • 2016
  • Marine seismic data have not only primary signals from subsurface but also ghost signals reflected from the sea surface. The ghost decreases temporal resolution of seismic data because it attenuates specific frequency components. For eliminating the ghost signals effectively, the exact ghost delaytimes and reflection coefficients are required. Because of undulation of the sea surface and vertical movements of airguns and streamers, the ghost delaytime varies spatially and randomly while acquiring seismic data. The reflection coefficient is a function of frequency, incidence angle of plane-wave and the sea state. In order to estimate the proper ghost delaytimes considering these characteristics, we compared the ghost delaytimes estimated with L-1 norm, L-2 norm and kurtosis of the deghosted trace and its autocorrelation on synthetic data. L-1 norm of autocorrelation showed a minimal error and the reflection coefficient was calculated using Kirchhoff approximation equation which can handle the effect of wave height. We applied the estimated ghost delaytimes and the calculated reflection coefficients to remove the source and receiver ghost effects. By removing ghost signals, we reconstructed the frequency components attenuated near the notch frequency and produced the migrated stack section with enhanced temporal resolution.

Regression model for the preparation of calibration curve in the quantitative LC-MS/MS analysis of urinary methamphetamine, amphetamine and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid using R (소변 중 메트암페타민, 암페타민 및 대마 대사체 LC-MS/MS 정량분석에서 검량선 작성을 위한 R을 활용한 회귀모델 선택)

  • Kim, Jin Young;Shin, Dong Won
    • Analytical Science and Technology
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    • v.34 no.6
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    • pp.241-250
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    • 2021
  • Calibration curves are essential in quantitative methods and for improving the accuracy of analyte measurements in biological samples. In this study, a statistical analysis model built in the R language (The R Foundation for Statistical Computing) was used to identify a set of weighting factors and regression models based on a stepwise selection criteria. An LC-MS/MS method was used to detect the presence of urinary methamphetamine, amphetamine, and 11-nor-9-carboxy-Δ9 -tetrahydrocannabinol in a sample set. Weighting factors for the calibration curves were derived by calculating the heteroscedasticity of the measurements, where the presence of heteroscedasticity was determined via variance tests. The optimal regression model and weighting factor were chosen according to the sum of the absolute percentage relative error. Subsequently, the order of the regression model was calculated using a partial variance test. The proposed statistical analysis tool facilitated selection of the optimal calibration model and detection of methamphetamine, amphetamine, and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in urine. Thus, this study for the selection of weighting and the use of a complex regression equation may provide insights for linear and quadratic regressions in analytical and bioanalytical measurements.