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Gradient-based history matching with a global optimization method

SPE JOURNAL 2001年第2期6卷 200-208页

作者： Gomez, S Gosselin, O Barker, JW Natl Autonomous Univ Mexico Inst Appl Math & Syst Mexico City DF Mexico TotalFinaElf Explorat London England

We investigate the application of a global optimization algorithm called the tunneling method to the problem of history matching of petroleum reservoirs. Results are presented for two test cases. The first is a small synthetic case in which the global minimum is known. The second is a real field example. In both cases, a series of minima was found. The computational cost of each tunneling phase is found to be comparable with the cost of each local minimization. It is concluded that the tunneling method may have a practical application in history matching as an alternative to immediate reformulation of the problem if the first minimum found does not represent an acceptable match.

关键词： mathematics local minima multiplier optimization problem optimization method initial point objective function global solution objective function value june 2001

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The combined effects of extracorporeal membrane oxygenation and renal replacement therapy on meropenem pharmacokinetics: a matched cohort study

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CRITICAL CARE 2014年第6期18卷 1-9页

作者： Shekar, Kiran Fraser, John F. Taccone, Fabio Silvio Welch, Susan Wallis, Steven C. Mullany, Daniel V. Lipman, Jeffrey Roberts, Jason A. Prince Charles Hosp Adult Intens Care Serv Crit Care Res Grp Brisbane Qld 4072 Australia Univ Queensland Brisbane Qld 4072 Australia Univ Libre Bruxelles Hop Erasme Dept Intens Care B-1070 Brussels Belgium St Vincents Hosp Intens Care Serv Sydney NSW 2000 Australia Univ Queensland Burns Trauma & Crit Care Res Ctr Brisbane Qld 4072 Australia

Introduction: The scope of extracorporeal membrane oxygenation (ECMO) is expanding;however, optimal drug prescription during ECMO remains a developing science. Currently, there are no clear guidelines for antibiotic dosing during ECMO. This open-label, descriptive, matched-cohort pharmacokinetics (PK) study aimed to compare the PK of meropenem in ECMO patients to critically ill patients with sepsis not receiving ECMO (controls). Methods: Eleven adult patients on ECMO (venovenous (VV) ECMO, n = 6;venoarterial (VA) ECMO, n = 5) receiving intravenous (IV) meropenem were included. Meropenem plasma concentrations were determined using validated chromatography. Population PK analysis was performed using non-linear mixed effects modelling. This data was compared with previously published meropenem PK data from 10 critically ill adult patients not on ECMO (preserved renal function (n = 5) or receiving renal replacement therapy (RRT) (n = 5). Using these data, we then performed Monte Carlo simulations (n = 1,000) to describe the effect of creatinine clearance on meropenem plasma concentrations. Results: In total, five (two VV, three VA) out of eleven ECMO patients received RRT. The other six patients (four VV, two VA) had no significant impairment in renal function. A two-compartment model adequately described the data. ECMO patients had numerically higher volume of distribution (0.45 +/- 0.17 versus 0.41 +/- 0.13 L/kg, P = 0.21) and lower clearance compared to controls (7.9 +/- 5.9 versus 11.7 +/- 6.5 L/h, P = 0.18). Variability in meropenem clearance was correlated with creatinine clearance or the presence of RRT. The observed median trough concentrations in the controls were 4.2 (0.0 to 5.7) mg/L. In ECMO patients, while trough meropenem concentrations >2 mg/L were achieved in all patients, a more aggressive target of >8 mg/L for less susceptible microorganisms was observed in only eight out of eleven patients, with five of them being on RRT. Conclusions: ECMO patients ex

关键词： Renal Replacement Therapy Meropenem objective function value ECMO Circuit Preserve Renal function

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Hybrid fuzzy clustering technique to enhance the performance based on a fusion of intuitionistic modified fuzzy c-means and improved genetic algorithm

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INTERNATIONAL JOURNAL OF DATA SCIENCE AND ANALYTICS 2023年 1-24页

作者： Kumar, Niteesh Kumar, Harendra Sharma, Dipa Gurukula Kangri Dept Math & Stat Haridwar Uttarakhand India Sri Dev Suman Univ Dept Math Pt LMS Campus Rishikesh Rishikesh Uttarakhand India

In the modern era, there is a sudden rise in data due to the wide use of the web, social networks and so on. Now, it becomes difficult to explore desired data from such fused complex data. For mining the data, many clustering algorithms have been proposed, and it is very difficult to find a clustering method which is suitable for all types of datasets. The present study proposes a hybrid fuzzy clustering technique based on the fusion of intuitionistic modified fuzzy c-means and improved genetic algorithm. This study overcomes the problem of high sensitivity toward initial centroids by using an improved genetic algorithm with developed normalized crossover and mutation operator. The proposed algorithm reduces the effect of noise by developing a metric and resolve uncertainty in assigning membership value by using two negation functions. The strength of the proposed algorithm over existing methods in the literature is revealed by testing it on 11 benchmark real-world and three artificial datasets. The experiment results state the admirable achievement of the proposed algorithm over other tested algorithms.

关键词： Crossover operator Fuzzy clustering Genetic algorithm Intuitionistic fuzzy set objective function value

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Evaluation of the Population Pharmacokinetic Properties of Lidocaine and its Metabolites After Long-Term Multiple Applications of a Lidocaine Plaster in Post-Herpetic Neuralgia Patients

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EUROPEAN JOURNAL OF DRUG METABOLISM AND PHARMACOKINETICS 2017年第5期42卷 801-814页

作者： Bursi, Roberta Piana, Chiara Grevel, Joachim Huntjens, Dymphy Boesl, Irmgard Grunenthal GmbH Global Innovat Data Sci Pharmacometr Zieglerstr 6 D-52099 Aachen Germany BAST Inc Ltd Loughborough Leics England Janssen Pharmaceut NV Global Clin Pharmacol Turnhoutseweg 30 B-2340 Beerse Belgium Grunenthal GmbH Global Innovat Clin Dev Zieglerstr 6 D-52099 Aachen Germany

Lidocaine 5% medicated plaster is the first lidocaine containing product for chronic use. As no previous investigations have been conducted to evaluate the population pharmacokinetics of long-term exposure to lidocaine 5% medicated plasters, further insights into the evaluation of the pharmacokinetic properties of lidocaine and its metabolites were needed for the assessment of its safety. The population pharmacokinetic properties of lidocaine and its metabolites were evaluated after multiple applications of lidocaine 5% medicated plasters based on data collected for up to 14.5 months from two phase III clinical trials (up to 2.5 months in the first trial, and up to 12 months in a follow-up trial) in post-herpetic neuralgia patients. Modeling was performed using nonlinear mixed effects as implemented in NONMEMA (R) (nonlinear mixed-effect modeling) v.5. A stepwise forward inclusion and backward elimination procedure were used for covariate model building. The model provides reliable estimates of the pharmacokinetic behavior of lidocaine after medicated plaster application. It was validated using simulations and showed adequate predictive properties. Apparent Clearance was estimated to be 48 L/h after application of two or fewer plasters, whereas its value increased to 67 L/h after application of three plasters. Model-based simulations predicted no accumulation of lidocaine or any of its metabolites after long-term exposure of three simultaneous plasters up to 1 year. The variability explained by adding covariates into the model for the long-term exposures of lidocaine following one plaster or three simultaneous plaster applications was found to be very small with respect to the overall between-subject variability. In conclusion, exposure to lidocaine after the application of the lidocaine medicated plaster was found to be primarily affected by the number of plasters simultaneously applied, i.e., it increased with the number of applied patches, but less than proportio

关键词： Herpes Zoster Lidocaine Medicate Plaster objective function value Visual Predictive Check

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Parameter optimization of PID controller based on an enhanced whale optimization algorithm for AVR system

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OPERATIONAL RESEARCH 2023年第3期23卷 44页

作者： Zhang, Jinzhong Zhang, Tan Zhang, Gang Kong, Min West Anhui Univ Sch Elect & Optoelect Engn Luan 237012 Peoples R China

This paper proposes an enhanced whale optimization algorithm based on a ranking-based mutation operator (EWOA) to stabilize the PID controller's parameters in the AVR system, and the intention is to arrive at the ideal objective function value by modifying the control parameters. The whale optimization algorithm is based on the humpback whale's bubble-net attacking behavior, which imitates shrinkage encircling prey, bubble-net attacking prey and random searching for prey to address the complicated optimization issue. The ranking-based mutation operator can maximize the selection probability, screen out the best search individual, eliminate premature convergence, promote the convergence speed and elevate the exploitation ability. The EWOA not only has substantial robustness and stability to strengthen the optimization efficiency and recognize the optimal solution but also combines exploration with exploitation to expand the convergence rate and calculation precision. The EWOA is contrasted with other algorithms to validate the practicability and usefulness. The experimental results demonstrate that the EWOA has a quicker convergence rate, higher computation precision, shorter execution time and greater stability, which is a remarkable and practical method for addressing the parameter optimization of the PID controller in the AVR system.

关键词： Whale optimization algorithm Ranking-based mutation operator objective function value Control parameters Experimental results

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Target-Mediated Drug Disposition Population Pharmacokinetics Model of Alirocumab in Healthy Volunteers and Patients: Pooled Analysis of Randomized Phase I/II/III Studies

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CLINICAL PHARMACOKINETICS 2017年第10期56卷 1155-1171页

作者： Djebli, Nassim Martinez, Jean-Marie Lohan, Laura Khier, Sonia Brunet, Aurelie Hurbin, Fabrice Fabre, David Sanofi 371 Rue Pr J Blayac F-34184 Montpellier 04 France Univ Montpellier UFR Pharm Pharmacocinet Montpellier France Inst Rech Cancerol Montpellier Montpellier France INSERM U1194 Montpellier France Inst Reg Canc Montpellier Montpellier France

Proprotein convertase subtilisin/kexin type 9 inhibition with monoclonal antibodies such as alirocumab significantly reduces low-density lipoprotein-cholesterol levels +/- other lipid-lowering therapies. We aimed to develop and qualify a population pharmacokinetics (PopPK) model for alirocumab in healthy subjects and patients, taking into account the mechanistic target-mediated drug disposition (TMDD) process. This TMDD model was developed using a subset of the alirocumab clinical trial database, including nine phase I/II/III studies (n = 527);the model was subsequently expanded to a larger data set of 13 studies (n = 2870). Potential model parameters and covariate relationships were explored, and predictive ability was qualified using a visual predictive check. The TMDD model was built using the quasi-steady-state approximation. The final TMDD-quasi-steady-state model included a significant relationship between distribution volume of the central compartment and disease state: distribution volume of the central compartment was 1.56-fold higher in patients vs. healthy subjects. Separately, application of the model to the expanded data set revealed a significant relationship between linear clearance and statin co-administration: linear clearance was 1.27-fold higher with statins. The good predictive performance of the TMDD model was assessed based on graphical and numerical quality criteria, together with the visual predictive check and comparison of the predictions to those from a PopPK model with parallel linear and Michaelis-Menten clearances (i.e., simplification of the TMDD PopPK model). This mechanistic TMDD PopPK model integrates the interaction of alirocumab with its target and accurately predicts both alirocumab and total proprotein convertase subtilisin/kexin type 9 concentrations in healthy subjects and patients.

关键词： Familial Hypercholesterolemia Linear Clearance objective function value PopPK Model Visual Predictive Check

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Population pharmacokinetics and pharmacodynamics of hydroxyurea in sickle cell anemia patients, a basis for optimizing the dosing regimen

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ORPHANET JOURNAL OF RARE DISEASES 2011年第1期6卷 1-12页

作者： Paule, Ines Sassi, Hind Habibi, Anoosha Pham, Kim P. D. Bachir, Dora Galacteros, Frederic Girard, Pascal Hulin, Anne Tod, Michel Univ Lyon Lyon France Univ Lyon 1 Fac Med Lyon Sud CTO EMR3738 Oullins France Univ Paris Est Creteil AP HP GH H Mondor Pharmacol Lab Creteil France Univ Paris Est Creteil AP HP GH H Mondor Ctr Reference Syndromes Drepanocytaires Majeu Creteil France Hosp Civils Lyon Hop Croix Rousse Lyon France

Background: Hydroxyurea (HU) is the first approved pharmacological treatment of sickle cell anemia (SCA). The objectives of this study were to develop population pharmacokinetic(PK)-pharmacodynamic(PD) models for HU in order to characterize the exposure-efficacy relationships and their variability, compare two dosing regimens by simulations and develop some recommendations for monitoring the treatment. Methods: The models were built using population modelling software NONMEM VII based on data from two clinical studies of SCA adult patients receiving 500-2000 mg of HU once daily. Fetal hemoglobin percentage (HbF %) and mean corpuscular volume (MCV) were used as biomarkers for response. A sequential modelling approach was applied. Models were evaluated using simulation-based techniques. Comparisons of two dosing regimens were performed by simulating 10000 patients in each arm during 12 months. Results: The PK profiles were described by a bicompartmental model. The median (and interindividual coefficient of variation (CV)) of clearance was 11.6 L/h (30%), the central volume was 45.3 L (35%). PK steady-state was reached in about 35 days. For a given dosing regimen, HU exposure varied approximately fivefold among patients. The dynamics of HbF% and MCV were described by turnover models with inhibition of elimination of response. In the studied range of drug exposures, the effect of HU on HbF% was at its maximum (median I-max was 0.57, CV was 27%);the effect on MCV was close to its maximum, with median value of 0.14 and CV of 49%. Simulations showed that 95% of the steady-state levels of HbF% and MCV need 26 months and 3 months to be reached, respectively. The CV of the steady-state value of HbF% was about 7 times larger than that of MCV. Simulations with two different dosing regimens showed that continuous dosing led to a stronger HbF% increase in some patients. Conclusions: The high variability of response to HU was related in part to pharmacokinetics and to pharmacodyna

关键词： Mean Corpuscular Volume objective function value Visual Predictive Check Fetal Hemoglobin Residual Error Model

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Decreasing Computational Times for Solving Static Elevator Operation Problems by Assuming Maximum Waiting Times 3

Decreasing Computational Times for Solving Static Elevator O...

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3rd IEEE Global Conference on Consumer Electronics (GCCE)

作者： Inamoto, Tsutomu Higami, Yoshinobu Kobayashi, Shin-ya Ehime Univ Grad Sch Sci & Engn Bunkyo 3 Matsuyama Ehime 7908577 Japan

ISBN: (纸本)9781479951468

In this paper, we propose a technique to decrease computational times for solving static elevator operation problems which are formalized as trip-based integer linear programming models. The technique is comprised of two parts: (i) to give equations which constrain the search space on the assumption that the maximum waiting time over passengers of an optimal solution is known, and (ii) to estimate such time as longest round-trip times. Computational results indicate that the technique can basically decrease computational times without degrading objective function values when maximum waiting times are less than estimated values and the number of equipped elevators is 1.

关键词： integer programming lifts linear programming operations research transportation computational time maximum waiting time objective function value static elevator operation problem trip-based integer linear programming model Computational modeling Elevators Equations Estimation Linear programming Mathematical model Optimization

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Are standard doses of piperacillin sufficient for critically ill patients with augmented creatinine clearance?

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CRITICAL CARE 2015年第1期19卷 28-28页

作者： Udy, Andrew A. Lipman, Jeffrey Jarrett, Paul Klein, Kerenaftali Wallis, Steven C. Patel, Kashyap Kirkpatrick, Carl M. J. Kruger, Peter S. Paterson, David L. Roberts, Michael S. Roberts, Jason A. Alfred Hosp Dept Intens Care & Hyperbar Med Melbourne Vic 3181 Australia Univ Queensland Burns Trauma & Crit Care Res Ctr Brisbane Qld 4029 Australia Royal Brisbane & Womens Hosp Dept Intens Care Med Brisbane Qld 4029 Australia QIMR Berghofer Med Res Inst Stat Unit Brisbane Qld 4029 Australia Monash Univ Fac Pharm & Pharmaceut Sci Melbourne Vic 3052 Australia Princess Alexandra Hosp Dept Intens Care Med Brisbane Qld 4102 Australia Royal Brisbane & Womens Hosp Dept Infect Dis Brisbane Qld Australia Univ Queensland Clin Res Ctr Brisbane Qld 4029 Australia Univ S Australia Sch Pharm & Med Sci Adelaide SA 5000 Australia

Introduction: The aim of this study was to explore the impact of augmented creatinine clearance and differing minimum inhibitory concentrations (MIC) on piperacillin pharmacokinetic/pharmacodynamic (PK/PD) target attainment (time above MIC (fT(> MIC))) in critically ill patients with sepsis receiving intermittent dosing. Methods: To be eligible for enrolment, critically ill patients with sepsis had to be receiving piperacillin-tazobactam 4.5 g intravenously (IV) by intermittent infusion every 6 hours for presumed or confirmed nosocomial infection without significant renal impairment (defined by a plasma creatinine concentration greater than 171 mu mol/L or the need for renal replacement therapy). Over a single dosing interval, blood samples were drawn to determine unbound plasma piperacillin concentrations. Renal function was assessed by measuring creatinine clearance (CLCR). A population PK model was constructed, and the probability of target attainment (PTA) for 50% and 100% fT(> MIC) was calculated for varying MIC and CLCR values. Results: In total, 48 patients provided data. Increasing CLCR values were associated with lower trough plasma piperacillin concentrations (P < 0.01), such that with an MIC of 16 mg/L, 100% f(T> MIC) would be achieved in only one-third (n = 16) of patients. Mean piperacillin clearance was approximately 1.5-fold higher than in healthy volunteers and correlated with CLCR (r = 0.58, P < 0.01). A reduced PTA for all MIC values, when targeting either 50% or 100% fT(>MIC), was noted with increasing CLCR measures. Conclusions: Standard intermittent piperacillin-tazobactam dosing is unlikely to achieve optimal piperacillin exposures in a significant proportion of critically ill patients with sepsis, owing to elevated drug clearance. These data suggest that CLCR can be employed as a useful tool to determine whether piperacillin PK/PD target attainment is likely with a range of MIC values.

关键词： Sequential Organ Failure Assessment Piperacillin Minimum Inhibitory Concentration Intermittent Infusion objective function value

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Vancomycin population pharmacokinetics during extracorporeal membrane oxygenation therapy: a matched cohort study

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CRITICAL CARE 2014年第6期18卷 1-10页

作者： Donadello, Katia Roberts, Jason A. Cristallini, Stefano Beumier, Marjorie Shekar, Kiran Jacobs, Frederique Belhaj, Asmae Vincent, Jean-Louis de Backer, Daniel Taccone, Fabio Silvio Univ Libre Bruxelles Erasme Hosp Dept Intens Care B-1070 Brussels Belgium Univ Queensland Burns Trauma & Crit Care Res Ctr Brisbane Qld Australia Prince Charles Hosp Adult Intens Care Serv Crit Care Res Grp Brisbane Qld 4032 Australia Univ Libre Bruxelles Erasme Hosp Dept Infect Dis B-1070 Brussels Belgium Univ Libre Bruxelles Erasme Hosp Dept Thorac Surg B-1070 Brussels Belgium

Introduction: The aim of this study was to describe the population pharmacokinetics of vancomycin in critically ill patients treated with and without extracorporeal membrane oxygenation (ECMO). Methods: We retrospectively reviewed data from critically ill patients treated with ECMO and matched controls who received a continuous infusion of vancomycin (35 mg/kg loading dose over 4 hours followed by a daily infusion adapted to creatinine clearance, CrCl)). The pharmacokinetics of vancomycin were described using non-linear mixed effects modeling. Results: We compared 11 patients treated with ECMO with 11 well-matched controls. Drug dosing was similar between groups. The median interquartile range (IQR) vancomycin concentrations in ECMO and non-ECMO patients were 51 (28 to 71) versus 45 (37 to 71) mg/L at 4 hours;23 (16 to 38) versus 29 (21 to 35) mg/L at 12 hours;20 (12 to 36) versus 23 (17-28) mg/L at 24 hours (ANOVA, P = 0.53). Median (ranges) volume of distribution (Vd) was 99.3 (49.1 to 212.3) and 92.3 (22.4 to 149.4) L in ECMO and non-ECMO patients, respectively, and clearance 2.4 (1.7 to 4.9) versus 2.3 (1.8 to 3.6) L/h (not significant). Insufficient drug concentrations (that is drug levels <20 mg/dL) were more common in the ECMO group. The pharmacokinetic model (non-linear mixed effects modeling) was prospectively validated in five additional ECMO-treated patients over a 6-month period. Linear regression analysis comparing the observed concentrations and those predicted using the model showed good correlation (r(2) of 0.67;P < 0.001). Conclusions: Vancomycin concentrations were similar between ECMO and non-ECMO patients in the early phase of therapy. ECMO treatment was not associated with significant changes in Vd and drug clearance compared with the control patients.

关键词： Vancomycin Continuous Renal Replacement Therapy Sequential Organ Failure Assessment Score Intermittent Infusion objective function value

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