Optimal Operating Characteristics Research Articles

An optimization framework for multi-timescale operations of pumped storage systems: Balancing stability and economy

Pumped storage hydropower system (PSHS) has multi-timescale operating characteristics which are divided into hour scale short-term scheduling and second scale power regulation with the objectives of minimizing water consumption and optimizing power regulation characteristics, respectively. However, the operating characteristics of these two scales are often analyzed independently, preventing decision makers from obtaining a strategy with optimal multi-timescale operating characteristics. This paper proposes a novel optimization framework by coupling the second scale model with the hour scale model which balances the stability (power regulation characteristics) with the economy (water consumption). Firstly, the power regulation characteristics of the unit under different operating conditions are summarized in terms of the integrated time and absolute error (ITAE) and maximum deviation of the rotational speed (ntdmax) based on a refined PSHS model. And a novel short-term scheduling model is developed which couples the power regulation characteristics. Secondly, with the novel model, the Pareto solution sets are obtained based on the non-dominated sorting genetic algorithm-III (NSGA-III) with the objective of minimizing the water consumption and ITAE/ntdmax. Finally, by the technique for order preference by similarity to an ideal solution (TOPSIS), the Pareto solution sets are further evaluated to obtain an operating strategy with optimal power regulation characteristics and water consumption. Compared to the traditional solution aiming for the minimum water consumption, this strategy results in a significant improvement in the stability (65.03 % reduction in ITAE and 68.43 % reduction in ntdmax) at the expense of a smaller economic behavior (0.0295 % increase in water consumption). The strategy outstands existing operating rules and innovatively introduces power regulation characteristics to obtain a short-term scheduling strategy that balances stability with economy. It provides a theoretical basis for the multi-timescale operation of PSHS.

Triglyceride Glucose Index: A Potential Indicator in the Evaluation of Graves Ophthalmopathy.

To determine the relationship between Graves ophthalmopathy (GO) and triglyceride glucose index (TGI) and to evaluate the predictive importance of this index in terms of GO activity. This retrospective study included 20 inactive GO patients, 20 active GO patients, and 20 healthy controls. TGI was calculated using fasting plasma triglyceride and fasting plasma glucose levels and values were compared between the groups. The receiver operating characteristics curve was used to calculate the optimal TGI cutoff value and the sensitivity and specificity of this value between active and inactive GO groups. No significant difference was detected between the groups in terms of age and gender (p = 0.561 and p = 0.762, respectively). TGI value was 8.49 (8.41, 8.67) in the control group, 8.76 (8.74, 8.87) in the inactive GO group, and 9.06 (8.87, 9.08) in the active GO group (p < 0.001 for control group vs. inactive GO group; p < 0.001 for control group vs. active GO group; p = 0.001 for inactive GO group vs. active GO group). The optimal receiver operating characteristics cutoff value of TGI between active and inactive GO groups was 8.86 with 85% sensitivity and 75% specificity (area under curve: 0.837, p < 0.001, 95% confidence interval: 0.711-0.964). TGI was higher in both inactive and active GO patients compared with controls. It also appears that TGI may be used as a predictive marker indicating GO activity. This cheap and easily accessible parameter may be beneficial in detecting the disease and monitoring its activity in clinical practice.

Optimal rule extraction-based real-time energy management strategy for series-parallel hybrid electric vehicles

Energy management strategy plays an important role in improving the fuel economy of hybrid electric vehicles. In this paper, an energy management strategy optimized by dynamic programming for a series–parallel hybrid electric vehicle is proposed. The key components of the powertrain system are modeled, and the model accuracy is corrected with the experimental data. To construct the real-time energy management strategy, the dynamic programming algorithm is employed first to find the optimal control benchmark, and then the control sequence with optimal fuel economy is obtained to analyze and build the mapping relationship between control variables and driving conditions. To fulfill the requirement of real-world application, the influence of the engine warm-up process on fuel consumption is also investigated. Finally, according to the optimal control datasets, the optimal operating mode distribution of clutches and the optimal power of the engine and motor are extracted to generate the real-time strategy. Benefiting from the optimal control sequence of dynamic programming, this study explores optimal operating characteristics of powertrain components towards fuel saving and enables the strategy conversion from global optimal to real-time application, which provides opportunities to achieve approximate optimal fuel economy of hybrid electric vehicles in real-time.

The Design of Nested Adaptive Clinical Trials of Multiple Organ Dysfunction Syndrome Children in a Single Study.

Describe the statistical design of the Personalized Immunomodulation in Sepsis-induced Multiple Organ Dysfunction Syndrome (MODS) (PRECISE) study. Children with sepsis-induced MODS undergo real-time immune testing followed by assignment to an immunophenotype-specific study cohort. Interventional cohorts include the granulocyte macrophage-colony stimulating factor (GM-CSF) for the Reversal of Immunoparalysis in Pediatric Sepsis-induced MODS (GRACE)-2 trial, which uses the drug GM-CSF (or placebo) to reverse immunoparalysis; and the Targeted Reversal of Inflammation in Pediatric Sepsis-induced MODS (TRIPS) trial, which uses the drug anakinra (or placebo) to reverse systemic inflammation. Both trials have adaptive components and use a statistical framework in which frequent data monitoring assesses futility and efficacy, allowing potentially earlier stopping than traditional approaches. Prespecified simulation-based stopping boundaries are customized to each trial to preserve an overall one-sided type I error rate. The TRIPS trial also uses response-adaptive randomization, updating randomization allocation proportions to favor active arms that appear more efficacious based on accumulating data. Twenty-four U.S. academic PICUs. Septic children with specific immunologic derangements during ongoing dysfunction of at least two organs. The GRACE-2 trial compares GM-CSF and placebo in children with immunoparalysis. The TRIPS trial compares four different doses of anakinra to placebo in children with moderate to severe systemic inflammation. Both trials assess primary efficacy using the sum of the daily pediatric logistic organ dysfunction-2 score over 28 days. Ranked summed scores, with mortality assigned the worst possible value, are compared between arms using the Wilcoxon Rank Sum test (GRACE-2) and a dose-response curve (TRIPS). We present simulation-based operating characteristics under several scenarios to demonstrate the behavior of the adaptive design. The adaptive design incorporates innovative statistical features that allow for multiple active arms to be compared with placebo based on a child's personal immunophenotype. The design increases power and provides optimal operating characteristics compared with traditional conservative methods.

Protection Coordination of Microgrids Using Dual Setting Directional Overcurrent Relays Based on Optimal Operating Characteristics and Curve Breakpoints

Protection Coordination of Microgrids Using Dual Setting Directional Overcurrent Relays Based on Optimal Operating Characteristics and Curve Breakpoints

Расчет оптимальных эксплуатационных характеристик газовых скважин с учетом термобарических условий пласта

Расчет оптимальных эксплуатационных характеристик газовых скважин с учетом термобарических условий пласта

Optimization of the main parameters of the diesel engine during its operation on the multicomponent biofuel composition

BACKGROUND: When conducting experimental studies aimed at finding optimal parameters of the diesel engine operating mode, as well as other objects, the issue of reducing the volume of the experiment becomes acute. The use of modern methods of planning, obtaining, processing and analyzing experimental data allows to reduce significantly the number of experiments conducted without notable loss of the reliability of the data obtained.&#x0D; AIMS: The aim of this study is to determine the optimal operating characteristics of the diesel engine, which uses the multi-component bio-fuel composition.&#x0D; METHODS: In order to determine the optimal values of the main parameters, affecting the effective indicators of the 4ChN 11.0/12.5 diesel engine when operating on the multicomponent biofuel composition and a mathematical description of their relationship, a second-order three-factor Box Benken plan was implemented. These factors are effective load, crankshaft rotational speed, and fuel injection advance angle. The diesel engine operation studies were performed on the most stable mixture of the multicomponent biofuel composition, including the following ingredients, wt %: rapeseed oil 34.5; ethanol 31.0; diesel fuel 34.5. The search of a compromise solution for the optimal combination of the levels of studied factors was performed with the method of superimposing of bidimensional sections of the response surfaces of the effective efficiency factor and the specific effective fuel consumption.&#x0D; RESULTS: Adequate models of second-order regression analysis of changes in effective efficiency factor and specific effective fuel consumption have been obtained. The factor space is described and grapho-analytical studies are carried out. The analysis of regression models and bidimensional sections of response surfaces allowed to determine the optimal values of the studied factors. The method for determining the optimal load and speed ranges of the diesel engine operation, using the multicomponent biofuel composition, has been optimized due to the application of the experimental plan and the description of the factor space by mathematical models, while number of experiments was reduced.&#x0D; CONCLUSIONS: The optimal area of the combination of the factors is in the range of varying the rotational speed of the diesel engine crankshaft n=1400...1550 rpm and the effective load Pe=0.68...0.85 MPa at the fuel injection advance angle Ѳinj=23.5 degrees to TDC. Considering the variable nature of the load and speed modes of a diesel engine in a real operation environment, the obtained data are of practical interest.

ALGORITHM FOR SELECTING A FLOW METER WITH OPTIMAL PARAMETERS

Problems. In many cases, the problem arises of choosing from a variety of alternatives to measuring instruments necessary for measuring the parameters of a technological process. So as that measuring instruments with different designs, operating principles and different technical and technological parameters are produced by different manufacturers. One of the important problems in the development of these systems is the selection of measuring instruments with optimal operational and metrological characteristics in accordance with the manufacturer's specifications and the terms of reference for the system design.&#x0D; Methodology. Multiple criteria decision-making (MCDM) are used in order to solve problems related to several criteria. The high accuracy sensors ensure accurate readings, although there are several parameters involved in measuring process: flow rate; gas or gases used; temperature; operating pressure; pressure drop; price; accuracy; response time; warm-up time; stable measurement range (turndown) gas is selected.&#x0D; Findings. Selection process of the optimal gas flow meter for information-measuring system is considered. Criteria for selection of the flow meters is studied, shown that the selection process is multi-criterial problem. Algorithm for selection of the gas flow meter is proposed. Proposed algorithm based on AHP method and TOPSIS. An idea of algorithm is following. İnitially experts select some alternatives, which meet all requirements for flow meters of different suppliers. At the next step the relative criteria of importance are calculated. After that decision matrixes are composed by which determine the preferences for the goals. &#x0D; Originality. Better alternative or flow meter with optimal parameters is determined by ranking of all alternatives. &#x0D; Practical value. Applying of the proposed algorithm increases reliability of the final decision and automates the selection process by using of the corresponding software.

Optimal Operational Characteristics of Wastewater Treatment Using Hydrocyclone in a Sequencing Batch Reactor Process

Optimal Operational Characteristics of Wastewater Treatment Using Hydrocyclone in a Sequencing Batch Reactor Process

Fuzzy-ChOA: an improved chimp optimization algorithm for marine mammal classification using artificial neural network.

Chimp optimization algorithm (ChOA) is a robust nature-inspired technique, which was recently proposed for addressing real-world challenging engineering problems. Due to the novelty of the ChOA, there is room for its improvement. Recognition and classification of marine mammals using artificial neural networks (ANNs) are high-dimensional challenging problems. In order to address this problem, this paper proposed the using of ChOA as ANN’s trainer. However, evolving ANNs using metaheuristic algorithms suffers from high complexity and processing time. In order to address this shortcoming, this paper proposes the fuzzy logic to adjust the ChOA’s control parameters (Fuzzy-ChOA) for tuning the relationship between exploration and exploitation phases. In this regard, we collect underwater marine mammals sounds and then produce an experimental dataset. After pre-processing and feature extraction, the ANN is used as a classifier. Besides, for having a fair comparison, we used a benchmark audio database of marine mammals. The comparison algorithms include ChOA, coronavirus optimization algorithm, harris hawks optimization, black widow optimization algorithm, Kalman filter benchmark algorithms, and also comparative benchmarks include convergence speed, local optimal avoidance ability, classification rate, and receiver operating characteristics (ROC). The simulation results show that the proposed fuzzy model can tune the boundary between the exploration and extraction phases. The convergence curve and ROC confirm that the convergence rate and performance of the designed recognizer are better than benchmark algorithms.

Optimization of the hybrid solar power plants comprising photovoltaic and concentrating solar power using the butterfly algorithm

This study optimized grid intermittency and instability resulting from photovoltaic (PV) by adding concentrating solar power (CSP) equipped with thermal energy storage (TES), which can be used to form hybrid solar power for grid dispatching. The PV–CSP were optimized by using a hybrid butterfly algorithm to meet the power generation demands and lowest system operation costs. Based on the optimal output and operating characteristics of hybrid power, the economics of peak-valley and fixed electricity prices were studied and compared. The optimal TES capacity was 6-h electricity generation. Hybrid power with optimal TES capacity could achieve a 4.2% increase for power production and 10.4% decrease for operation cost. The peak-valley price provided a better economic benefit than the fixed electricity price. A reasonable configuration of TES can ensure the flexibility and stability of hybrid plant. Hybrid power contributes to a flexible use of dispatch capabilities by equipped with TES, making PV power completely utilize, especially during the periods of high solar radiation. For power systems, hybrid power can be used to replace partly conventional thermal power to achieve highly economic and environmental benefits.

Design and partial load operation optimization of integrated ship energy system based on supercritical CO2 waste heat recovery cycle

In the present work, a supercritical CO2 cycle, designed for recovering waste heat originating specifically from heavy-duty turbocharged diesel engines, constitutes the basis of an integrated energy system. The purpose of this system is to cover the time-varying power loads required during the operation of ships, appearing in diverse forms of energy (propulsive/mechanical, electrical, thermal). Optimization procedures are applied for the determination of the optimal design and of the optimal operational characteristics of the CO2 cycle during partial loading conditions. Appropriate techno-economic criteria are used for evaluating the optimality of the proposed engineering solutions. The effects of the added capital costs of the CO2 cycle on its useful power output are investigated, while the temporal variations of the energy loads are appropriately taken into account in the determination of the optimum CO2 cycle design characteristics. The inclusion of the CO2 cycle is economically justified, while a reduction of operational fuel costs from 5.8% to 6.3 % is achieved for a typical yearly energy profile, according to the optimal allocation of the useful power produced by the CO2 waste heat recovery cycle towards the propulsive or electric loads.

Two Strategies in Transient Change Detection

The paper addresses the transient change detection (TCD) problem, assuming that the duration of change is finite. The TCD criterion minimizes the worst-case probability of missed detection among all tests with a prescribed worst-case probability of false alarm. We study the fixed sample size (FSS) test as a solution to the TCD problem. First, the operating characteristics of the FSS test have been established for arbitrary pre- and post-change distributions. Next, a numerical method of the sample (block) size optimization has been considered for three particular log-likelihood ratio distributions, i.e., Gaussian, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\chi ^{2}$</tex-math></inline-formula> and exponential. Moreover, simple asymptotic equations for the optimal operating characteristics and block size have been proposed in the Gaussian case. Numerical results are provided to confirm the theoretical findings for the above-mentioned distributions. The accuracy and sharpness of the asymptotic analytical equation is analyzed in the Gaussian case. Finally, the FSS test is compared to the finite moving average (FMA) test obtained by optimizing the CUSUM-type test with respect to the TCD optimality criterion for the above-mentioned distributions. The application of the FSS and FMA tests to the radio-navigation integrity monitoring is also considered.

Выбор геометрических характеристик фронтового устройства и длины камеры сгорания прямоточного типа

A method has been developed for selecting the geometric characteristics of the front and the length of the direct-flow combustion chamber. Afterburner combustion chambers are of the ramjet type and are used for a short-term increase in the thrust of a gas turbine engine during takeoff, for overcoming the sound barrier by an aircraft and for flying at supersonic speed, and for making maneuvers. As part of ramjet engines, ramjet combustion chambers are used as the main combustion chambers in which the process of fuel combustion and heat supply to the working fluid is ensured. The developed method for selecting the geometric characteristics consists in optimizing the main operating characteristics of the combustion chamber. Mathematical models are proposed for describing the dependence of the total pressure loss, the combustion efficiency and the range of stable operation of the combustion chamber against the parameters of the flow at the inlet to the combustion chamber and the geometric characteristics of the front device and the length of the combustion chamber. The analysis of the dependences of the combustion chamber working characteristics on the geometric characteristics of the front-line device and its length is carried out. As a result of the analysis of mathematical models, a list of the main geometric characteristics of the front device was determined, on which the total pressure loss, the combustion efficiency and the range of stable operation of the combustion chamber depend. Optimization parameters, optimization criterion and limits for solving the optimization problem are determined. As an implementation of the optimization method, it is proposed to use a diagram of the combustion chamber performance in the coordinates of the optimization parameters. The developed method makes it possible to ensure the optimal basic operating characteristics of the combustion chamber - total pressure loss, combustion efficiency and combustion stability limits.

Clinical value of amyloid-beta1-40 as a marker of thrombo-inflammation in antiphospholipid syndrome.

Amyloid-beta1-40 (Aβ40) is a pro-inflammatory peptide under investigation as a novel biomarker of vascular inflammation, endothelial dysfunction and atherothrombosis in the general population. Herein we tested the hypothesis that Aβ40 is deregulated in APS, a systemic autoimmune disease characterized by a thrombo-inflammatory state. Between January 2016 and July 2017, we consecutively recruited 80 regularly followed thrombotic APS patients (44 primary, 36 SLE/APS) and 80 age- and sex-matched controls. Plasma Aβ40 levels were measured using ELISA and APS-related clinical and laboratory characteristics were recorded. The adjusted Global Anti-Phospholipid Syndrome Score (aGAPSS), a validated risk score in APS, was calculated as a comparator to Aβ40 performance to detect arterial thrombotic APS-related events. Higher Aβ40 levels were significantly associated with the presence of APS [odds ratio (OR) 1.024 per 1 pg/ml (95% CI 1.007, 1.041)] after adjustment for cardiovascular risk factors (CVRFs), including smoking, arterial hypertension, dyslipidaemia and BMI, and for estimated glomerular filtration rate (eGFR). Among APS patients, increased high-sensitivity CRP (hs-CRP) serum levels was the only independent determinant of Aβ40 levels. Importantly, Aβ40 levels above the optimal receiver operating characteristics (ROC)-derived cut-off value were independently associated with recurrent arterial events [OR 4.93 (95% CI 1.31, 18.51)] after adjustment for age, sex, CVRFs, hs-CRP and high anti-β2 glycoprotein I IgG titres. Finally, by ROC curve analysis, Aβ40 provided incremental additive value over the aGAPSS by significantly improving its discrimination ability for recurrent arterial thromboses. In APS, Aβ40 plasma levels are elevated and associated with an adverse thrombo-inflammatory profile. The pathophysiological and prognostic role of Aβ40 in APS merits further investigation.

Impact of Automatization of Irrigation: Case Study

This paper presents an analysis, considering the scientific and technological development, as well as the legal framework, of the La Purisima Dam irrigation system in Guanajuato. The results of this research will eventually improve the productive systems of the users of the irrigation system by having knowledge of the optimal operating characteristics. The Modernization, Automation and Technification Project of the La Purisima Dam Irrigation Module, in Guanajuato, Mexico, began in 2011 and estimates an investment of 520 million pesos to technify 3 thousand hectares and increase efficiency in the use of water and its conduction. For a better performance in agricultural irrigation, which represents an increase in the overall production of the system between 40 and 85% and an increase in driving of 95% and savings of 10 million m3, which are extracted annually from the Irapuato Valle Aquifer. The objective of the research is to analyze the meanings that the agricultural producers have of the Irrigation District 011, with the purpose of favoring social participation in the implementation of the PMAYT and achieving an improvement in life. This research began in 2016, with users of the module located in Irapuato. The procedures applied in 2018 were questionnaires, semi-structured interviews and a focus group based on the methodology of the grounded theory. Among the results, the interest of producers in the knowledge of new irrigation systems stands out, but ignorance of regulations and lack of resources were detected. It is concluded that in addition to the technical challenge of modernization, meanings must be given to social participation and to understand the benefits of the development of science and technology as a complement to traditional knowledge, so that the projects are successful and the results are obtained.

Gut Microbiome Signatures Are Predictive of Infectious Risk Following Induction Therapy for Acute Myeloid Leukemia.

The majority of studies that provide insights into the influence of the microbiome on the health of hematologic malignancy patients have concentrated on the transplant setting. Here, we sought to assess the predictive capacity of the gastrointestinal microbiome and its relationship to infectious outcomes in patients with acute myeloid leukemia (AML). 16s rRNA-based analysis was performed on oral swabs and stool samples obtained biweekly from baseline until neutrophil recovery following induction chemotherapy (IC) in 97 AML patients. Microbiome characteristics were correlated with clinical outcomes both during and after IC completion. At the start of IC, higher stool Shannon diversity (hazard ratio [HR], 0.36; 95% confidence interval [CI], .18-.74) and higher relative abundance of Porphyromonadaceae (HR, 0.36; 95% CI, .18-.73) were associated with increased probability of remaining infection-free during neutropenia. A baseline stool Shannon diversity cutoff of <2 had optimal operating characteristics for predicting infectious complications during neutropenia. Although 56 patients received therapy >72 hours with a carbapenem, none of the patients had an infection with an extended spectrum β-lactamase-producing organism. Patients who received carbapenems for >72 hours had significantly lower α-diversity at neutrophil recovery (P = .001) and were approximately 4 times more likely to have infection in the 90 days following neutrophil recovery (HR, 4.55; 95% CI, 1.73-11.93). Our results suggest that gut microbiome evaluation could assist with infectious risk stratification and that improved targeting of antibiotic administration during IC could decrease subsequent infectious complications in AML patients.Baseline microbiome diversity is a strong independent predictor of infection during acute myeloid leukemia induction chemotherapy (IC) among clinical and microbiome covariates. Higher baseline levels of Porphyromonadaceae appear protective against infection, while carbapenem use is associated with consequences to the microbiome and infection susceptibility post-IC.

Differentiating borderline personality from bipolar disorder with the Mood Disorder Questionnaire (MDQ): A replication and extension of the International Mood Network (IMN) Nosology Project

IntroductionVöhringer et al. identified a triad of items on the Mood Disorder Questionnaire (MDQ) that best discriminated between borderline personality disorder (BPD) and bipolar disorder (BD) in a tertiary mood clinic setting [23]. The present study aimed to replicate and extend these findings by examining the performance of the triad across a range of cut-off scores and comparing the operating characteristics of the triad to the full MDQ. MethodsPatients presenting for treatment were assessed with the Structured Clinical Interview for DSM-IV (SCID) and the BPD module of the Structured Interview for DSM-IV Personality (SIDP-IV). The present report is based on 476 depressed patients who had a principal diagnosis of major depressive disorder or BD and who completed the MDQ. ResultsFifty-seven patients were diagnosed with BD and fifty-four patients were diagnosed with BPD. Both the triad and full MDQ significantly predicted BD diagnosis (p < .001), but the triad had optimal operating characteristics, particularly at a cut-off of two. ConclusionWithin a sample of depressed patients, the MDQ triad is a better screener for BD than the full MDQ, particularly if a positive triad screen is indicated by the presence of any two items. The triad is particularly good for differentiating between BD and BPD, whereas the full MDQ does a poorer job of differential diagnosis. Future studies should administer the triad as a stand-alone scale.

Analysis and Design of a High-Frequency DC/DC Converter Based on a Resonant Rectifier

In high-frequency dc/dc converters, the resonant rectifier is an important stage that guarantees high efficiency and optimal operating characteristics. However, the existing design approaches are based on trial methods and cannot achieve optimal results. A systematic and effective design method for a current-driven class E circuit is proposed in this paper, which consists of the detailed theoretical analysis and numerical derivation. Furthermore, with the optimal design method, the input impedance of the resonant rectifier can maintain quasi-resistive characteristics. Demonstration of this approach is provided through the experimental results of a 20 MHz dc/dc prototype. The system efficiency can be as high as 81.5% based on the optimal design method of the rectifier.

Study on the optimal operating characteristics for lithium -ion batteries used in hybrid electric motorcycle

This study presents a short overview about Lithium-Ion (Li-ion) batteries and its applicability on either hybrid-electric vehicles (HEVs) or motorcycle with the hybrid transmission in particular. This study deals with optimal operating characteristics calculation, comparison, and experiment Li-ion battery for HEM (Hybrid Electric Motorcycle) application, which is renovated from Honda Lead 110cc with the direct-driven front wheel by Brushless DC Electric Motor, the rear wheel is driven by internal combustion engine with the original continuously variable transmission (CVT). Both of them are able to provide torque independently or concurrently. The results of this research can be used to study optimal power source and the operating cost of the vehicle after renovation.