• Title/Summary/Keyword: Mean Curve

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Estimation of Rivers Discharge by Probabilistic Velocity Function Considering Hydraulic Characteristics (하천 수리특성을 고려한 확률론적 유속공식에 의한 하천유량 산정)

  • Choo, Tai Ho;Lee, Sang Jin;Park, Sang Woo;Oh, Ryun Su
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.6B
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    • pp.537-542
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    • 2009
  • To improve stage-discharge curve equation considering water level's function, this study suggested the method that can efficiently compute rivers discharge based on hydraulic characteristics such as river width, area, channel bed slope and entropy concept adopting probabilistic approach. This scheme is proposed to estimate discharge from the velocity formulation based on the entropy function in the equilibrium state derived from the relation between mean and maximum flow velocity. It has been tested using field and laboratory hydraulic data collected from the Alberta university in Canada. As a result it was found that the method proposed in this study was more efficient and accurate comparing with the traditional stage-discharge curve equation.

Influence of the Lumbar Spine Adjustment using the Lumbar Roll Support on Head and Neck Posture in Older Adults (요추 지지대에 의한 노인의 요추만곡 조절이 머리와 목 자세에 미치는 영향)

  • Ko, Seung-Hyun;Kim, Yu-Shin;Yoon, Bum-Chul
    • The Journal of the Korea Contents Association
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    • v.11 no.12
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    • pp.800-806
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    • 2011
  • The objective of this study was to identify the effect of lumbar lordotic curve adjustment on head and neck posture in older adults. Methods Twenty healthy older participants (mean age 71.32) were photographed while watching monitor in sitting with or without lumbar roll support(length 28cm, diameter 10cm). The upper cervical angle and lower cervical angle were measured using the NIH ImageJ 1.32. Comparisons between upper and lower cervical angle with or without lumbar roll support were made using paired-t test analysis. Results Subjects demonstrated a significant difference in the mean upper and lower cervical angle. Mean difference of the upper cervical angle was about $2.83^{\circ}$ with and without lumbar roll support(p<0.005). Mean difference of the lower cervical angle was about $4.44^{\circ}$ with and without lumbar roll support(p<0.0001). Conclusions This study showed that healthy older adults demonstrated more ability to maintain an upright posture of cervical spine during lumbar lordotic curve maintenance with lumbar roll support than without lumbar roll support. When the clinicians consider improvement of the head and neck posture in older adults, they must incorporate adjustment in the lumbar region.

A Study on the Estimation of Discharge in Unsteady Condition by Using the Entropy Concept (엔트로피 개념에 의한 부정류 유량 산정에 관한 연구)

  • Choo, Tai Ho;Chae, Soo Kwon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.12
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    • pp.6159-6166
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    • 2012
  • A discharge measurement is difficult in flood season which is especially important in the water resources field and the continuous discharge measurement for all rivers is impossible on the present system. So, the stage-discharge curve has been used for a long time to produce discharge data of rivers. However, there has been problems from a reliability angle due to the fact that this method uses only stage-discharge relationship, although the stage-discharge curve has the convenience. Therefore, a new mean velocity equation was derived by using Chiu's 2D velocity formula of the entropy concept in this paper. The derived equation reflected hydraulic characteristics such as the depth, gravity acceleration, hydraulic radius, energy slope, kinematic coefficient of viscosity, etc. and estimated also a maximum velocity. In addition, this method verified the relationship between a mean and maximum velocity and estimates an equilibrium state ${\phi}(M)$ well presenting properties of a river cross section as the results. The mean velocity was estimated by using the equilibrium state ${\phi}(M)$, and then the discharge was estimated. To prove this equation to be accurate, the comparison between the measured and estimated discharge is conducted by using the measured laboratory data in the unsteady condition flow showing loop state and the results are consistent. If this study is constantly carried out by using various laboratory and river data, this method will be widely utilized in water resources field.

Comparison of pooled Versus Individual Sera in Avian Infectious Bronchitis Virus Seroprevalence Study (닭 전염성 기관지염 바이러스의 혈청 유병률 연구에서 개별혈청과 합병혈청의 비교)

  • Kim, Sa-Rim;Kwon, Hyuk-Moo;Sung, Haan-Woo;Pak, Son-Il
    • Journal of Veterinary Clinics
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    • v.23 no.4
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    • pp.416-420
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    • 2006
  • Compare to testing sera individually, pooled-serum testing has considered as a cost-effective method, particularly on a large population-based seroprevalence studies. This study was to determine the relationship between individual sera and pooled sera titers for detection of avian infectious bronchitis virus (IBV) and to evaluate suitability of pooled sera by comparing prevalences estimated from both samples. A total of 5,000 individual samples were collected from 500 flocks in Chungcheong, Gyunsgi, and Kangwon provinces between January 2005 and February 2006. Ten samples were randomly selected from each flock. Five-hundred pooled sera were prepared by mixing equal amount of each 10 individual serum from the original samples. IBV antibody titers were measured by hemagglutination inhibition (HI) test. The least squares regression analysis was performed to construct equation between pooled and mean individual titers. To determine whether the flock is infected 4 arbitrary criteria were used: detection of at least 1 chicken with HI titer ${\ge}$ 9 (criterion 1), detection of at least 2 samples with HI titer ${\ge}$9 (criterion 2), detection of at least 1 sample with HI titer ${\ge}$ 10 (criterion 3), and filially detection of at least 1 sample with HI titer ${\ge}$ 11 (criterion 4). The receiver operating characteristic (ROC) curve was used to examine the cut-off points of pooled titers showing optimal diagnostic accuracy. The area under the curve (AUC), sensitivities (Se), specificities (Sp), and positive (PPV) and negative (NPV) predictive values were calculated. The regression equation between pooled titers (pool) and mean individual titers (mean) was: $pool= 1.2498+0.8952{\times}mean$, with coefficient of determination of 87% (p< 0.0001). The optimal cut-off points of pooled titers were titer 8 for criterion 1 (AUC=0.975, Se=0.883, Sp=0.959, PPV=0.985, NPV=0.728), titer 8 for criterion 2 (AUC=0.969, Se=0.954, Sp=0.855, PPV=0.926, NPV=0.907), titer 9 for criterion 3 (AUC=0.970, Se=0.836, Sp=0.967, PPV=0.978, NPV=0.772), and titer 9 for criterion 4 (AUC= 0.946, Se=0.928, Sp=0.843, PPV=0.857, NPV=0.921). The difference of 'prevalence estimated by individual and pooled sample showed a minimum of 2% for criteria 2 and a maximum of 9.1:% for criteria 3. These results indicate that the use of pooled sera in HI test for screening IBV infection in laying hen flocks is considered as a cost-effective method of testing large numbers of samples with high diagnostic accuracy.

Diagnostic Significance of the Delta Neutrophil Index and Other Conventional Parameters in Neonatal Bacteremia (신생아 균혈증에서 Delta Neutrophil Index의 진단적 의의)

  • Koh, Il Doo;Jeon, Ihn Soo;Kim, Hwang Min
    • Pediatric Infection and Vaccine
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    • v.24 no.1
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    • pp.1-6
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    • 2017
  • Purpose: We investigated the effectiveness of the delta neutrophil index (DNI) for the prediction of neonatal bacteremia and compared it to other indices. Methods: A total of 146 pediatric patients, aged less than 31 days, admitted to the neonatal intensive care unit of Wonju Severance Christian Hospital with fever before or during hospitalization were enrolled in this study. We divided the patients into two groups based on the existence of neonatal bacteremia and performed blood culture tests on both groups. We examined white blood cell count, absolute neutrophil count, DNI, platelet count, and C-reactive protein (CRP) test. We used a receiver operating characteristic (ROC) curve to evaluate their diagnostic significance. Results: Seventy-seven patients were diagnosed with neonatal bacteremia. The mean gestational age was 38.74 weeks and the mean birth weight was 3.20 kg. The mean gestational age of the control group was 33.34 weeks and the mean birth weight was 2.20 kg. Causative organisms of bacteremia included Staphylococcus aureus (n=22), Staphylococcus epidermidis (n=18), and Streptococcus agalactiae (n=8). Both DNI and CRP were significantly associated with neonatal bacteremia after adjusting for gestational age and birth weight. The area under the ROC curve (AUC) for DNI (0.70) was higher than that for CRP (0.68). Conclusions: The DNI can be used to effectively predict neonatal bacteremia. The prediction will be more accurate if DNI is used in conjunction with other indices. In future, it will be useful to compare DNI with other indices and investigate its relationship with prognosis.

A Study on High Temperature Low Cycle Fatigue Crack Growth Modelling by Neural Networks (신경회로망을 이용한 고온 저사이클 피로균열성장 모델링에 관한 연구)

  • Ju, Won-Sik;Jo, Seok-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.4
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    • pp.2752-2759
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    • 1996
  • This paper presents crack growth analysis approach on the basis of neural networks, a branch of cognitive science to high temperature low cycle fatigue that shows strong nonlinearity in material behavior. As the number of data patterns on crack growth increase, pattern classification occurs well and two point representation scheme with gradient of crack growth curve simulates crack growth rate better than one point representation scheme. Optimal number of learning data exists and excessive number of learning data increases estimated mean error with remarkable learning time J-da/dt relation predicted by neural networks shows that test condition with unlearned data is simulated well within estimated mean error(5%).

Application of Bootstrap Method to Primary Model of Microbial Food Quality Change

  • Lee, Dong-Sun;Park, Jin-Pyo
    • Food Science and Biotechnology
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    • v.17 no.6
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    • pp.1352-1356
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    • 2008
  • Bootstrap method, a computer-intensive statistical technique to estimate the distribution of a statistic was applied to deal with uncertainty and variability of the experimental data in stochastic prediction modeling of microbial growth on a chill-stored food. Three different bootstrapping methods for the curve-fitting to the microbial count data were compared in determining the parameters of Baranyi and Roberts growth model: nonlinear regression to static version function with resampling residuals onto all the experimental microbial count data; static version regression onto mean counts at sampling times; dynamic version fitting of differential equations onto the bootstrapped mean counts. All the methods outputted almost same mean values of the parameters with difference in their distribution. Parameter search according to the dynamic form of differential equations resulted in the largest distribution of the model parameters but produced the confidence interval of the predicted microbial count close to those of nonlinear regression of static equation.

Seismic damage vulnerability of empirical composite material structure of adobe and timber

  • Si-Qi Li
    • Earthquakes and Structures
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    • v.25 no.6
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    • pp.429-442
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    • 2023
  • To study the seismic vulnerability of the composite material structure of adobe and timber, we collected and statistically analysed empirical observation samples of 542,214,937 m2 and 467,177 buildings that were significantly impacted during the 179 earthquakes that occurred in mainland China from 1976 to 2010. In multi-intensity regions, combined with numerical analysis and a probability model, a non-linear continuous regression model of the vulnerability, considering the empirical seismic damage area (number of buildings) and the ratio of seismic damage, was established. Moreover, a probability matrix model of the empirical seismic damage mean value was provided. Considering the coupling effect of the annual and seismic fortification factors, an empirical seismic vulnerability curve model was constructed in the multiple-intensity regions. A probability matrix model of the mean vulnerability index (MVI) was proposed, and was validated through the above-mentioned reconnaissance sample data. A matrix model of the MVI of the regions (19 provinces in mainland China) based on the parameter (MVI) was established.

Bioavailability and Comparative Pharmacokinetics of Two Enrofloxacin Formulations in Broiler Chickens (육계에서 경구투여시 enrofloxacin 제제에 따른 생체이용율 및 약물동태)

  • 윤효인;박승춘
    • Journal of Veterinary Clinics
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    • v.14 no.2
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    • pp.195-200
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    • 1997
  • In order to compare the pharmacokinetic profiles of enrofloxacin-HCL)ENFLX-HCL) and enrofloxacin-KOH (ENFLX-KOH) after oral administration in broiler chickens, the study was performed. The chickens used in this study weighed $1.82 {\pm}0.2 kg$ and clinically healthy. The dose of intravenous and lral administration was 5 mg per kg of body weight as enrofloxacin. After intravenous injection of enrofloxacin, it showed two-compartment model with the rapid distribution phase and the slow elimination phase. The mean apparent volume of distribution (Vd) was 2.70 l/kg. The mean half-life of elimination and distribution showed 8.26 h and 0.44 h, respectively. The mean area under curve (AUC) was calculated as $19.7 {\mu} g{\cdot} h/ml$. After oral administration of ENFLX-HCL and ENFLX-KOH with a rate of dose 5 mg of enrofloxacin/kg of body weight, Both of the products were showed one-compartment model unlike that of i.v. enrofloxacin standard solution showed the mean bioavailability of 79.64% for the ENFLX-KOG and 86.24% for the ENFLX-HCL. The mean total body clearance of the former was 0.24 l/kg/h and the latter 0.42 l/kg/h. Both enorfloxacin formulations seemed to have good tissue distribution and penetration as indicated by large volume of distribution : 2.72 l/kg for the -KOH and 4.44 l/kg for the -HCL. With the results obtained in this study, ENFLX-HCL could be used in place of its salt form in chickens.

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Skin Region Detection Using a Mean Shift Algorithm Based on the Histogram Approximation

  • Byun, Ki-Won;Nam, Ki-Gon;Ye, Soo-Young
    • Transactions on Electrical and Electronic Materials
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    • v.13 no.1
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    • pp.10-15
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    • 2012
  • In conventional, skin detection methods using for skin color definitions is based on prior knowledge. By experimentation, the threshold value for dividing the background from the skin region is determined subjectively. A drawback of such techniques is that their performance is dependent on a threshold value which is estimated from repeated experiments. To overcome this, the present paper introduces a skin region detection method. This method uses a histogram approximation based on the mean shift algorithm. This proposed method applies the mean shift procedure to a histogram of a skin map of the input image. It is generated by comparing with the standard skin colors in the $C_bC_r$ color space. It divides the background from the skin region by selecting the maximum value according to the brightness level. As the histogram has the form of a discontinuous function. It is accumulated according to the brightness values of the pixels. It is then, approximated by a Gaussian mixture model (GMM) using the Bezier curve technique. Thus, the proposed method detects the skin region using the mean shift procedure to determine a maximum value. Rather than using a manually selected threshold value, as in existing techniques this becomes the dividing point. Experiments confirm that the new procedure effectively detects the skin region.