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Tracking is a crucial problem for nonlinear systems as it ensures stability and enables the system to accurately follow a desired reference signal. Using Takagi–Sugeno (T–S) fuzzy models, this paper addresses the problem of fuzzy observer and control design for a class of nonlinear systems. The Takagi–Sugeno (T–S) fuzzy models can represent nonlinear systems because it is a universal approximation. Firstly, the T–S fuzzy modeling is applied to get the dynamics of an observational system in order to estimate the unmeasurable states of an unknown nonlinear system. There are various kinds of nonlinear systems that can be modeled using T–S fuzzy systems by combining the input state variables linearly. Secondly, the T–S fuzzy systems can handle unknown states as well as parameters known to the indirect adaptive fuzzy observer. A simple feedback method is used to implement the proposed controller. As a result, the feedback linearization method allows for solving the singularity problem without using any additional algorithms. A fuzzy model representation of the observation system comprises parameters and a feedback gain. The Lyapunov function and Lipschitz conditions are used in constructing the adaptive law. This method is then illustrated by an illustrative example to prove its effectiveness with different kinds of nonlinear functions. A well-designed controller is effective and its performance index minimizes network utilization—this factor is particularly significant when applied to wireless communication systems. [ABSTRACT FROM AUTHOR]

Grain drying environmental parameters are an important issue throughout the paddy grain production process. A real-time monitoring system requires rapid, online, and accurate measurement results. In the paddy grain drying process, the heated air velocity, temperature, relative humidity, and moisture content have to be carefully monitored and maintained to ensure product quality and safety. This study aimed to propose a real-time paddy grain drying and monitoring system using a long-range internet of things (LoRa-IoT). The real-time monitoring system consisted of sensors, LoRa, and IoT platforms. The LoRa end node and gateway were utilized as a wireless radio communication platform of IoT for long-distance signal transmission. From the experiment, the gateway received data from the end node at a distance of 2 km with a time on air (ToA) of 981 ms. As a result, the proposed monitoring system succeeded in measuring and recording the heated air velocity, temperature, and relative humidity data during the paddy grain drying process from 25% moisture content down to 14%. Regarding moisture content, the accuracy of real-time monitoring information was confirmed with a direct measurement method, resulting in a root mean square error (RMSE) of 6.17%. [ABSTRACT FROM AUTHOR]

The categories of the direct and the indirect can be classified as paired. The author applied standard and interdisciplinary research methods to the direct and the indirect as criminalistic categories. The article is a review that investigates the direct and the indirect through the subject of criminology; it is an attempt to define their signs as paired categories of criminology. The resulting theoretical and practical rationale of the correlation between the direct and the indirect in criminology reveals the methodological and subject-practical levels. Investigative and judicial practice prove that the direct and the indirect manifest themselves as tandem phenomena in the process of forensic cognition; therefore, they are paired categories of criminology. This conclusion is of great practical importance in criminal investigation and court trials, especially in the sphere of crimes against environment.

Abstract Tracking is a crucial problem for nonlinear systems as it ensures stability and enables the system to accurately follow a desired reference signal. Using Takagi–Sugeno (T–S) fuzzy models, this paper addresses the problem of fuzzy observer and control design for a class of nonlinear systems. The Takagi–Sugeno (T–S) fuzzy models can represent nonlinear systems because it is a universal approximation. Firstly, the T–S fuzzy modeling is applied to get the dynamics of an observational system in order to estimate the unmeasurable states of an unknown nonlinear system. There are various kinds of nonlinear systems that can be modeled using T–S fuzzy systems by combining the input state variables linearly. Secondly, the T–S fuzzy systems can handle unknown states as well as parameters known to the indirect adaptive fuzzy observer. A simple feedback method is used to implement the proposed controller. As a result, the feedback linearization method allows for solving the singularity problem without using any additional algorithms. A fuzzy model representation of the observation system comprises parameters and a feedback gain. The Lyapunov function and Lipschitz conditions are used in constructing the adaptive law. This method is then illustrated by an illustrative example to prove its effectiveness with different kinds of nonlinear functions. A well-designed controller is effective and its performance index minimizes network utilization—this factor is particularly significant when applied to wireless communication systems.

Objective: Thyroid disorders are prevalently diagnosed yet face significant challenges in their accurate identification in China. Predominantly, the reference intervals (RIs) currently in use across Chinese medical facilities derive from company-provided data, lacking stringent scientific validation. This practice underscores the urgent necessity for establishing tailored RIs for thyroid-related hormones, specifically tailored to the coastal area populations. Such refined RIs are imperative for empowering clinicians with the precise tools needed for the accurate diagnosis of both overt and subclinical thyroid conditions. Methods: This investigation analyzed the medical histories of 6021 euthyroid individuals mainly from East coastal area of China between June 2019 and December 2020. The cohort comprised residents of coastal areas, focusing on extracting insights into the regional specificity of thyroid hormone levels. A thorough examination protocol was implemented, encompassing inquiries into thyroid health history, ultrasound screenings, palpations during thyroid surgery, detections of thyroid antibodies, and reviews of medication histories. Adherence to the CLSI C28-A3 guidelines facilitated the derivation of RIs for thyroid-related hormones, subsequently juxtaposed against those provided by commercial entities. Results: The study delineated the following gender- and age-specific RIs for Thyroid-Stimulating Hormone (TSH): for males under 50 years, 0.57-3.37; males over 50 years, 0.51-4.03; females under 50 years, 0.53-3.91; and females over 50 years, 0.63-4.31. Further analysis revealed the RIs for Free Thyroxine (FT4), Free Triiodothyronine (FT3), Total Thyroxine (TT4), and Total Triiodothyronine (TT3) amongst males and females, with notable distinctions observed between the two genders and across age brackets. These findings are in stark contrast to the standardized intervals provided by manufacturers, particularly highlighting differences in TT3 and FT3 levels between genders and a tendency for TSH levels to increase with age. Conclusion: This research successfully establishes refined RIs for thyroid-related hormones within the Chinese coastal area populations, taking into account critical demographic factors such as gender and age. These tailored RIs are anticipated to significantly enhance the diagnostic accuracy for thyroid diseases, addressing the previously noted discrepancies with manufacturer-provided data and underscoring the importance of regionally and demographically adjusted reference intervals in clinical practice. [ABSTRACT FROM AUTHOR]

The introduction of trifluoromethylsulfinyl group into the required target molecules has become an indispensable strategy for pharmaceutical chemists to improve the success of new drug discovery. Compared with the indirect methods, direct trifluoromethylsulfinylation by employing available trifluoromethylsulfinylating reagents is an important and elegant strategy for the rapid assembly of valuable CF3S(O)‐derived organic molecules. This review focuses on the recent synthetic approaches and future perspectives of trifluoromethylsulfinyl compounds based on the indirect and direct methods in this area. These transformations proceed effectively with high yields and good functional group compatibility under mild conditions. [ABSTRACT FROM AUTHOR]

This paper considers a non‐standard Optimal Control problem that has an application in economics. The primary focus of this research is to solve the royalty problem, which has been categorized as a non‐standard Optimal Control problem, where the final state value and its functional performance index value are unknown. A new continuous necessary condition is investigated for the final state value so that it will convert the final costate value into a non‐zero value. The research analyzes the seven‐stage royalty piecewise function, which is then approximated to continuous form with the help of the hyperbolic tangent function and solves the problem by using a new modified shooting method. This modified shooting method applies Sufahani–Ahmad–Newton–Brent–Royalty Algorithm and Sufahani‐Ahmad‐Powell‐Brent‐Royalty Algorithm. For a validation process, the results are compared with the existing methods such as Euler, Runge–Kutta, Trapezoidal, and Hermite–Simpson approximations, and the results show that the proposed method yields an accurate terminal state value. [ABSTRACT FROM AUTHOR]

Background/Objectives: We present a software package called reflimR (Version 1.0.6), which enables rapid and transparent verification of reference intervals from routine laboratory measurements. Our method makes it easy to compare the results with specified target values and facilitates the interpretation of deviations using traffic light colors. Methods: The algorithm includes three procedural steps: (a) definition of an appropriate distribution model, based on Bowley's quartile skewness, (b) iterative truncation, based on a modified boxplot method to obtain the central 95% of presumably inconspicuous results, and (c) extrapolation of reference limits from a truncated normal quantile–quantile plot. Results: All algorithms have been combined into one consolidated library, which can be called in the R environment with a single command reflim (x). Using an example dataset included in the package, we demonstrate that our method can be applied to mixed data containing a substantial proportion of pathological values. It leads to similar results as the direct guideline approach as well as the more sophisticated indirect refineR software package. As compared to the latter, reflimR works much faster and needs smaller datasets for robust estimates. For the interpretation of the results, we present an intuitive color scheme based on tolerance ranges (permissible uncertainty of laboratory results). We show that a relatively high number of published reference limits require careful reevaluation. Conclusions: The reflimR package closes the gap between direct guideline methods and the more sophisticated indirect refineR method. We recommend reflimR for the rapid routine verification of large amounts of reference limits and refineR for a careful analysis of unclear or doubtful results from this check. [ABSTRACT FROM AUTHOR]

Background: Clinical laboratory tests are being evaluated with reference intervals (RI). Therefore, it is important that each laboratory determines and classifies its own reliable RI for each test to ensure an accurate and effective interpretation. The proposed method for determining RI is the "direct" approach, but it is a difficult, troublesome, time-consuming, and expensive method. An alternative approach is the “indirect” approach. In this study, we aimed to compare the RI values determined by the indirect method from the Calcium (Ca), Magnesium (Mg), Phosphate (P), 25-Hydroxy Vitamin D (25(OH)D), and Parathyroid hormone (PTH) test results with the RI provided by the manufacturer. Methods: A total of 1,520,314 Ca, Mg, P, 25(OH)D, and PTH test results, which were studied in our laboratory between January and November 2022, were included in the study. Data cleaning was done for individuals between the ages of 18 - 89, and only one record was allowed. The Tukey method was used to determine and exclude extreme values. Ca and Mg tests were divided into age groups (18 - 59 and 60 - 89 years), P, 25(OH)D, and PTH tests were divided into female - male groups. RI was calculated by using the Bhattacharya and Hoffmann methods. CLIA 19 acceptable limits were used to evaluate the compliance with the manufacturer's RI. Results: The RI results obtained by applying the Bhattacharya and Hoffmann methods were found to be significantly consistent and compatible with each other. According to the manufacturer's RI, Ca and Mg were compatible with RI in both methods, P was considered compatible with PTH and 25(OH)D upper reference limit in the Bhattacharya method, P was considered compatible with 25(OH)D lower reference limit and PTH upper reference limit in the Hoffmann method, while 25(OH)D lower reference limit was found to be different in the Bhattacharya method, and 25(OH)D upper reference limit and PTH lower reference limit were found to be different in the P male group in the Hoffmann method. Conclusions: We believe that it is of great importance for each laboratory to determine the RI specific for the population they serve and to choose the analytical method they use according to age and gender while periodically updating them to interpret the test results correctly. [ABSTRACT FROM AUTHOR]

Adopting a mentalist approach to the study of language attitudes, social prestige and stigma, as well as the values and stereotypes bestowed on Sardinian and Italian and their speakers were studied for the first time in Sardinia using the Matched-Guise Technique. The experiment was administered to Sardinian students of different ages, from different parts of the island, with different degrees of Italian/Sardinian bilingualism. Results show that Sardinian speakers are more favourably perceived in terms of friendliness and social pleasantness. Both Italian and Sardinian speakers, with no statistical difference between them, received moderately positive evaluations in traits related to socio-economic and cultural status, suggesting a decline in the traditional negative stereotypes associated with minority language speakers. Moreover, participants' self-reported use and competence of languages, as well as their amount of school activities involving Sardinian, turned out to interact with the attitudes towards the minority language, as higher values of those variables were associated with higher ratings for Sardinian speakers. Findings could be useful to policy-makers in efforts to maintain Sardinia's multilingual repertoire, and, more generally, to the scientific community in understanding the patterns and most relevant factors that affect language attitudes in bilingual contexts involving an endangered minority language. [ABSTRACT FROM AUTHOR]

Abstract Background The aim is to establish and verify reference intervals (RIs) for serum tumor markers for an apparently healthy elderly population in Southwestern China using an indirect method. Methods Data from 35,635 apparently healthy elderly individuals aged 60 years and above were obtained in West China Hospital from April 2020 to December 2021. We utilized the Box-Cox conversion combined with the Tukey method to normalize the data and eliminate outliers. Subgroups are divided according to gender and age to examine the division of RIs. The Z-test was used to compare differences between groups, and 95% distribution RIs were calculated using a nonparametric method. Results In the study, we observed that the RIs for serum ferritin and Des-γ-carboxy prothrombin (DCP) were wider for men, ranging from 64.18 to 865.80 ng/ml and 14.00 to 33.00 mAU/ml, respectively, compared to women, whose ranges were 52.58 to 585.88 ng/ml and 13.00 to 29.00 mAU/ml. For other biomarkers, the overall RIs were established as follows: alpha-fetoprotein (AFP) 0–6.75 ng/ml, carcinoembryonic antigen (CEA) 0–4.85 ng/ml, carbohydrate antigen15-3 (CA15-3) for females 0–22.00 U/ml, carbohydrate antigen19-9 (CA19-9) 0–28.10 U/ml, carbohydrate antigen125 (CA125) 0–20.96 U/ml, cytokeratin 19 fragment (CYFRA21-1) 0–4.66 U/ml, neuron-specific enolase (NSE) 0–19.41 ng/ml, total and free prostate-specific antigens (tPSA and fPSA) for males 0–5.26 ng/ml and 0–1.09 ng/ml. The RIs for all these biomarkers have been validated through our rigorous processes. Conclusion This study preliminarily established 95% RIs for an apparently healthy elderly population in Southwestern China. Using real-world data and an indirect method, simple and reliable RIs for an elderly population can be both established and verified, which are suitable for application in various clinical laboratories.

Introduction: Direct ways of establishing reference intervals for analytes are time-consuming and costly. Bhattacharya analysis is an indirect way to mathematically derive reference intervals from the results of analytes in a hospital database and is practically a simple and inexpensive alternative to direct methods. Methods: Data of serum uric acid, magnesium, and plasma homocysteine levels measured in the department of clinical biochemistry over 3 years were extracted from the hospital database along with the age, gender, and location of the patients. Bhattacharya analysis was performed by identifying underlying Gaussian distribution within the non-Gaussian distribution of the patient data by log transformation of the distribution of the data. Reference intervals for each of the analytes were calculated from the identified Gaussian distribution. Results: The reference interval for serum uric acid was 1.49–8.97 mg/dL in men and 2.13–6.14 in women, serum magnesium in adults was 1.19–3.21 mg/dL, and plasma homocysteine in adults was 4.6–21 μg/dL. Conclusion: Using Bhattacharya analysis, we were able to derive reference intervals for analytes from our hospital data.

Correct interpretation of thyroid function tests relies on correct reference intervals (RIs) for thyroid-stimulating hormone (TSH) and free thyroxine (FT4). ISO15189 mandates periodic verification of RIs, but laboratories struggle with cost-effective approaches. We investigated whether indirect methods (utilizing historical laboratory data) could replace the direct approach (utilizing healthy reference individuals) and compared results with manufacturer-provided RIs for TSH and FT4. We collected historical data (2008–2022) from 13 Dutch laboratories to re-establish RIs by employing indirect methods, TMC (for TSH) and refineR (for FT4). Laboratories used common automated platforms (Roche, Abbott, Beckman or Siemens). Indirect RIs (IRIs) were determined per laboratory per year and clustered per manufacturer (>1.000.000 data points per manufacturer). Direct RIs (DRIs) were established in 125 healthy individuals per platform. TSH IRIs remained robust over the years for all manufacturers. FT4 IRIs proved robust for three manufacturers (Roche, Beckman and Siemens), but the IRI upper reference limit (URL) of Abbott showed a decrease of 2 pmol/L from 2015. Comparison of the IRIs and DRIs for TSH and FT4 showed close agreement using adequate age-stratification. Manufacturer-provided RIs, notably Abbott, Roche and Beckman exhibited inappropriate URLs (overall difference of 0.5–1.0 µIU/mL) for TSH. For FT4, the URLs provided by Roche, Abbott and Siemens were overestimated by 1.5–3.5 pmol/L. These results underscore the importance of RI verification as manufacturer-provided RIs are often incorrect and RIs may not be robust. Indirect methods offer cost-effective alternatives for laboratory-specific or platform-specific verification of RIs. [ABSTRACT FROM AUTHOR]

Background: Reference intervals are essential for the interpretation of clinical laboratory tests and patient management. This study aims to determine age and gender reference intervals of complete blood count (CBC) in the Moroccan population by using the indirect approach. Methods: The study used data of ostensibly healthy adults collected retrospectively using the laboratory information system (LIS) of the Laboratory for Research and Medical Analysis of the Fraternal Royal Gendarmerie in Rabat (Morocco), between January 2018 and February 2020. The study included 5,898 men and 10,172 women ranging in age from 18 to 90 years. The lower and upper reference limits of CBC parameters were calculated using the nonparametric technique, as suggested by the Clinical and Laboratory Standards Institute (CLSI). Results: All hematological parameters showed no clinically significant gender-related differences, except small differences in the values of hemoglobin (HB), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). There were also no clinically significant agerelated differences for median values of all hematology analytes in both genders, except for platelet count (PLT) that continued to decline with increasing age in men and women, and Red blood cell count (RBC), Hematocrit (HCT), and hemoglobin (HB) that tended to increase with age but decrease in older age groups in men while they tended to increase with age in women. Conclusions: The indirect method can be used to establish reference intervals for CBC, with appropriate selection criteria and statistical tools. Our findings differed from the reference ranges provided in the textbook and also in other countries' reports. [ABSTRACT FROM AUTHOR]

Background: The aim is to establish and verify reference intervals (RIs) for serum tumor markers for an apparently healthy elderly population in Southwestern China using an indirect method. Methods: Data from 35,635 apparently healthy elderly individuals aged 60 years and above were obtained in West China Hospital from April 2020 to December 2021. We utilized the Box-Cox conversion combined with the Tukey method to normalize the data and eliminate outliers. Subgroups are divided according to gender and age to examine the division of RIs. The Z-test was used to compare differences between groups, and 95% distribution RIs were calculated using a nonparametric method. Results: In the study, we observed that the RIs for serum ferritin and Des-γ-carboxy prothrombin (DCP) were wider for men, ranging from 64.18 to 865.80 ng/ml and 14.00 to 33.00 mAU/ml, respectively, compared to women, whose ranges were 52.58 to 585.88 ng/ml and 13.00 to 29.00 mAU/ml. For other biomarkers, the overall RIs were established as follows: alpha-fetoprotein (AFP) 0–6.75 ng/ml, carcinoembryonic antigen (CEA) 0–4.85 ng/ml, carbohydrate antigen15-3 (CA15-3) for females 0–22.00 U/ml, carbohydrate antigen19-9 (CA19-9) 0–28.10 U/ml, carbohydrate antigen125 (CA125) 0–20.96 U/ml, cytokeratin 19 fragment (CYFRA21-1) 0–4.66 U/ml, neuron-specific enolase (NSE) 0–19.41 ng/ml, total and free prostate-specific antigens (tPSA and fPSA) for males 0–5.26 ng/ml and 0–1.09 ng/ml. The RIs for all these biomarkers have been validated through our rigorous processes. Conclusion: This study preliminarily established 95% RIs for an apparently healthy elderly population in Southwestern China. Using real-world data and an indirect method, simple and reliable RIs for an elderly population can be both established and verified, which are suitable for application in various clinical laboratories. [ABSTRACT FROM AUTHOR]

The wet desulphurisation and denitrification technique based on micro-nano bubbles, which is available by either D-method or I-method, is a promising novel process. By employing piped water, Na2SO3 aqueous solution and HA-Na aqueous solution as the absorption liquids, a comparative study was conducted in this article on D-method and I-method to analyze their performance, advantages and disadvantages. It was accompanied by an investigation of how initial pH and initial temperature values of the absorption liquids affected the removal efficiency. The results suggested a positive correlation between NO/SO2 removal efficiencies and pH values but a little improvement in the removal efficiency under alkaline conditions. Furthermore, heating the absorption liquids inhibited the removal of NO and SO2. When manipulated in the same experimental environment, D-method and I-method did not present a significant difference in the SO2 removal efficiency, while the former was remarkably more effective than the latter in removing NO. To put together, D-method had higher removal efficiency, but required a large-scale micro-nano bubble generator to process a large quantity of flue gas as the micro-nano bubble generator was subject to a limited inlet flow rate. Consequently, an increase in investment and operating costs was incurred, while this issue could be avoided by I-method. [ABSTRACT FROM AUTHOR]

In recent years, HRB400 and HTRB600 steel bars have become the mainstream standard reinforcing steel used in concrete structures in China. However, significant controversy still exists regarding the selection of material constitutive models and the determination of model parameters for buckling, fatigue, hysteresis, and other material characteristics. In this article, an automated process of multi-parameter calculation of the constitutive model for reinforcing steel – simulation accuracy evaluation of the constitutive model – selection of the constitutive model of reinforcing steel is established based on the hybrid programming method using MATLAB and OpenSees software. First, tensile and low-cycle fatigue tests were carried out on HRB400 and HTRB600 steel bars. Second, based on the constitutive model in OpenSees software and the skeleton curve and characteristics such as yielding, fatigue, and hysteresis, the constitutive model parameters of HRB400 and HTRB600 steel bars are determined using indirect and direct fitting methods. Finally, the five similarity parameters of the simulated normalized cumulative hysteretic energy dissipation coefficient are compared with the test results. The results indicate that the simulation accuracy of the Reinforcing Steel model exceeds 72%, which is higher than other four models, making it the best choice for reinforcing steel in numerical simulation.

ABSTRACT: Three broiler experiments were conducted to estimate the Ca equivalency of a novel phytase using direct and indirect methods. All 3 experiments employed 4 concentrations of limestone to create 4 reference diets, deficient in nonphytate P, with increasing dietary Ca. Phytase was supplemented to the lowest Ca reference diet at 350, 700, 1,400, or 2,800 FYT/kg in experiment (Exp.) 1 and Exp. 2 and at 500, 1,000, 2,000, or 4,000 FYT/kg in Exp. 3. Broilers were fed from d 8 to 10 and 20 to 24, 19 to 21, or 7 to 10 and 7 to 21 posthatching in Exp. 1, 2, or 3, respectively. Diet did not affect growth performance or tibia ash in Exp. 1. Reducing the dietary Ca linearly (P < 0.05) increased body weight gain (BWG) and feed intake (FI) in Exp. 2 or Exp. 3. Feed conversion ratio (FCR) was decreased (linear or quadratic, P < 0.05) as dietary Ca was reduced in Exp. 2 or Exp. 3 (d 7–21). Tibia ash percent linearly (P < 0.05) decreased as dietary Ca decreased in Exp. 3 but only from d 7 to 21 and phytase increased (linear or quadratic, P < 0.05) FI and BWG, and decreased FCR. In Exp. 1 (d 8–10) and Exp. 2, apparent ileal digestibility (AID), total tract retention, and apparent digested and retained Ca or P increased (linear or quadratic, P < 0.05) as dietary Ca decreased. Phytase increased (linear or quadratic, P < 0.05) AID and apparent digested and retained Ca or P in Exp. 1 or Exp. 2. Due to the nature of the effect of dietary Ca on performance or tibia ash, it was not possible to use the indirect method to estimate the Ca equivalence of phytase in the current experiments. The total and digestible Ca equivalence of phytase could be estimated using the direct method. These experiments highlight challenges to consider when designing experiments to estimate the Ca equivalency for phytase in the future.

The electrocaloric properties of commercially modified Pb(Zr,Ti)O 3 - (PZT)-based soft and hard ceramics were investigated by the indirect estimation via measurement of temperature–electric field P (T,E) hysteresis loops. The adiabatic temperature change ΔT due to electrocaloric effects was estimated from the polarization change of these samples. Both positive and negative electrocaloric temperature change was obtained for all ceramics. The existence of the negative electrocaloric effect was related to the FE-FE field-induced phase transition, between rhombohedral and monoclinic phases that occur in PZT ceramics synthesized near the morphotropic phase boundary. The resulting negative electrocaloric temperature change reveals higher values for the hard-type ceramics (∼-1.5 K for PIC 300) than for the soft-type. Insignificant positive effect values were achieved for all ceramics. The highest values of positive ECE were recorded for PIC 155 (soft) and PIC 181 (hard) and are of the order of ΔT = 0.67 K. In this case, no correlation was observed between the type of PZT ceramics soft or hard. [ABSTRACT FROM AUTHOR]

In space mission design, an important operational constraint is planned periodic coast arcs during which various mission-critical tasks such as navigation or ground communications are performed. These constraints, typically implemented as thruster duty cycles, can be characterized as discrete coast arcs enforced periodically during intervals of deterministic thrusting. A typical approach to incorporate duty cycles is by enforcing maximum thrust levels that are less than a nominal value. This work presents an embedded homotopy indirect optimization method for a smooth enforcement of discrete duty-cycle constraints for low-thrust trajectory optimization. The complexity of enforcing such discrete constraints is two-fold: (1) a precise event-detection strategy is needed to determine the beginning of deterministic thrust arcs, which must be successively updated along the trajectory and (2) a smooth modeling of the discrete coast events occurring on the order of 10s or even 100s depending on the duration of deterministic thrust arcs. Duty cycle constraints are enforced at the level of the Hamiltonian using a Composite Smooth Control (CSC) method, producing high-resolution optimal control solutions conscious of planned duty cycle coast arcs. Numerical solutions are presented for the heliocentric transfer phases of three space missions. The results are then validated against the Evolutionary Mission Trajectory Generator (EMTG), one of NASA's global trajectory optimization tools used for interplanetary mission design and capable of the explicit enforcement of periodic duty cycle coasting. The proposed indirect method is suitable for obtaining high-resolution trajectory solutions with realistically enforced thruster duty cycle, which could then be used as high-quality initial guesses in flight-fidelity mission planning tools. The proposed smooth modeling of discrete coast arcs can also be customized to enforce periodic and non-periodic thrust shutdown constraints. • Duty-cycle aware, multi-revolution, low-thrust, minimum-fuel trajectories. • A novel smooth switching function for embedding forced coast arcs. • Composite Smooth Control (CSC) is used to embed the discrete duty-cycle constraints. • Comparison with NASA's Evolutionary Mission Trajectory Generator (EMTG). • Julia programming language is used for solution of the boundary-value problems. [ABSTRACT FROM AUTHOR]

This study investigated the time-optimal low-thrust interplanetary transfer problem, and proposes a fast estimation method for guessing the initial costate and optimal transfer time based on a surrogate model, and applied it to the problem of the 11th Global Trajectory Optimization Competition (GTOC 11). Two core methods are proposed in this paper: (1) a fast generation method called the neighbor point iteration algorithm (NPIA) is presented for rapidly generating low-thrust databases with high efficiency and accuracy; and (2) deep neural networks (DNNs) are adopted to learn the state–costate pairs of low-thrust databases, and the surrogate network can quickly estimate the initial costate and optimal transfer time of the low-thrust interplanetary problem. Experiments verified the proposed method and investigated the influence of network structure, learning rate, and loss function on the accuracy of network estimation. The effects of database generation and network estimation were compared based on three transfer scenarios: coplanar, non-coplanar, and arbitrary orbital transfer. In addition, the application case study showed that the proposed method can quickly obtain the time-optimal low-thrust solution to GTOC 11's interplanetary transfer, which achieves high precision and meets the terminal constraints. [ABSTRACT FROM AUTHOR]

The uniform trigonometrization method (UTM) faces two difficulties in solving the Mars entry problem with maximum terminal altitude. One is that two possible solutions need to be evaluated by Pontryagin's minimum principle (PMP). The other one is that using numerical continuation logic to solve the Hamiltonian two-point boundary value problem (TPBVP) involves a significant amount of computation. To overcome these two challenges, indirect sequential convex programming (ISCP), which combines the UTM and sequential convex programming (SCP), is developed in this article. The proposed method first modifies the two control options into a single solution, which eliminates the requirement for PMP evaluation. The nonlinear TPBVP resulted from the improved UTM is then relaxed into a convex programming problem that is established by introducing the virtual control and buffer. Subsequently, the SCP process generates a numerical solution to the Mars entry problem within a short time. Compared to the general pseudospectral method and UTM, simulations demonstrate the effectiveness and efficiency of the ISCP method for longitudinal Mars entry missions with or without path constraints. • The two solutions of the uniform trigonometrization method are improved to one. • The two-point boundary value problem is solved by sequential convex programming. • The bang-bang solution is obtained by indirect sequential convex programming. [ABSTRACT FROM AUTHOR]

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Reference intervals (RIs) are the cornerstone for evaluation of test results in clinical practice and are invaluable in judging patient health and making clinical decisions. Establishing RIs based on clinical laboratory data is a branch of real-world data mining research. Compared to the traditional direct method, this indirect approach is highly practical, widely applicable, and low-cost. Improving the accuracy of RIs requires not only the collection of sufficient data and the use of correct statistical methods, but also proper stratification of heterogeneous subpopulations. This includes the establishment of age-specific RIs and taking into account other characteristics of reference individuals. Although there are many studies on establishing RIs by indirect methods, it is still very difficult for laboratories to select appropriate statistical methods due to the lack of formal guidelines. This review describes the application of real-world data and an approach for establishing indirect reference intervals (iRIs). We summarize the processes for establishing iRIs using real-world data and analyze the principle and applicable scope of the indirect method model in detail. Moreover, we compare different methods for constructing growth curves to establish age-specific RIs, in hopes of providing laboratories with a reference for establishing specific iRIs and giving new insight into clinical laboratory RI research. (201 words) [ABSTRACT FROM AUTHOR]

The problem of indirect single-position coordinate determination based on the smoothed measurements of bearing and the radial velocity of an object is solved considering motion invariants and singular measurement errors. Such errors are represented as an appropriate linear combination with unknown spectral coefficients in a given finite-dimensional functional space. Possible application of the developed method to different models of motion and observation is considered. Analytical relations are derived for estimating accuracy characteristics and methodological errors. A comparative evaluation of computational cost is presented. [ABSTRACT FROM AUTHOR]

Eflornithine (2-fluoromethyl-DL-ornithine) is a potent and irreversible inhibitor that selectively targets ornithine decarboxylase, a key enzyme in the polyamine biosynthesis pathway. Due to the lack of chromophoric moiety in the eflornithine structure, its detection via UV detector is difficult. Thus, direct high-performance liquid chromatographic (HPLC) separation of enantiomers of Eflornithine is not feasible, and pre-column derivatization is required for its determination through chiral HPLC columns. We developed an indirect HPLC method using (S)-α-ethyl benzylamine as a chiral derivatizing agent for the enantioseparation of Eflornithine. The diastereomers thus produced were then separated via LiChrospher C18 column (5 μm particle size, L × I. D. 25 cm × 4.6 mm). The mobile phase used was a mixture of acetonitrile and 0.1% aq. TFA and varied in linear gradients of 30–70% of acetonitrile for 30 min run at a flow rate of 1.0 mL min−1 and UV detection at 320 nm. The separation parameters were optimized by altering the mobile phase composition and flow rate. The findings revealed that the chromatographic separation was accomplished within 15 min, with resolution values greater than 4.5 for Eflornithine enantiomers. The detection and quantitation limits were 9.26 ng mL− 1 and 18.52 ng mL− 1 for Eflornithine enantiomers. [ABSTRACT FROM AUTHOR]

The world over energy resources are getting scarcer and increasingly exorbitant with time. In India bridging the ever- widening gap between energy demand and supply by increasing supply is an expensive option. The share of energy costs in total production costs can, therefore improve profit levels in all the industries. Thermal Power Plant is a major source of electricity production by coal. We will understand the overview of Thermal Power Plant i.e its parts such as boiler, turbine etc. Overview of Thermal Power Plant is very important for its better functioning and for its maintenance. The satisfactory design consist of selection of sites; estimation of cost; selection of Boiler, Turbine, Electrical Generator, Cooling System. The Transportation of electrical energy is more economical to the transportation of coal. So, we have to put greater efforts on thermal power plant as it is very economical for us. This reduction can be achieved by improving the efficiency of industrial operations and equipments. Energy plays an important role in identifying energy conservation opportunities in the industrial sector, while they do not provide the final answer to the problem; they do help to identify potential for energy conservation and induces the companies to concentrate their efforts in this area in a focused manner. [ABSTRACT FROM AUTHOR]

Simple Summary: Reducing the incidence of mastitis is one of the primary objectives of dairy farms. Currently, new rapid diagnostic methods, both direct (culture) and indirect, are being introduced; these methods serve to detect the number of somatic cells in milk. This study was conducted to compare them; in the study, three indirect methods were tested (the California Mastitis Test, the Porta somatic cell count milk test, and the DeLaval cell counter). Their agreement, sensitivity, and specificity were analyzed with laboratory somatic cell count (SCC) measurements. The highest agreement (83.1%) and sensitivity (81.0%) were recorded with the CMT, and the highest specificity (97.5%) was determined with the DeLaval cell counter. When comparing the agreement of elevated SCCs, the highest value of tested farm methods with bacterial findings was found with the Porta SCC (73.7%). Based on the given results, it can be concluded that all these tests can be used in the rapid diagnosis of subclinical mastitis since each test has certain advantages over the others. The aim of this study was to compare three on-farm commercial methods for the indirect detection of subclinical mastitis in dairy cows: the California mastitis test (CMT), the Porta side somatic cell count milk test (Porta SCC), and the DeLaval cell counter (DCC), with the Fossomatic cell count (FSCC), and to evaluate the relationship between the determined somatic cell count SCC and the occurrence of intramammary pathogens in the milk of dairy cows. A total of 284 sensory unchanged mixed milk samples, collected during the milking on a dairy farm, were analyzed in this study for somatic cell counts by the mentioned on-farm tests. Quarter milk samples (n = 583) from all the selected cows were cultured. The agreement, sensitivity, and specificity of the three indirect commercial diagnostic tests (the CMT, the Porta SCC, and the DeLaval cell counter) were calculated, and the FSCC was used as the gold standard. The results were analyzed statistically using the Pearson correlation test and the paired t-test. The CMT matched with the FSCC in 83.1% of the samples, with the Porta SCC in 80.6%, and with the DCC in 80.3% of the samples. The sensitivity and specificity reached 81.0% and 92.9% for the CMT, 79.4% and 90.7% for the Porta SCC, and 75.8% and 97.5% for the DCC, respectively. The correlation between the FSCC and the Porta SCC was 0.86 (p < 0.0001), and between the FSCC and the DCC, it was 0.92 (p < 0.0001). The differences between them were insignificant. Bacteria were detected in 130 (22.3%) quarter milk samples. The most prevalent bacteria were Enterococcus spp. (36.2%), followed by E. coli (20%), coagulase-negative staphylococci (13.1%), A. viridans (9.2%), Streptococcus spp. (9.2%), Proteus spp. (6.2%), and S. intermedius (3.9%). Contagious isolates (S. aureus) were detected in 3 quarter milk samples (2.3%). The agreement between the individual tests and the microbiological culture was as follows: 69.2% for the CMT; 73.7% for the Porta SCC; 71.6% for the DCC; and 76.5% for the FSCC. Higher SCCs were detected in the milk samples contaminated with bacteria than in the healthy milk (p < 0.001). No significance was found between the presence of individual species of intramammary pathogens and the different levels of SCCs. Based on the results, bacteria are the predominant cause of subclinical mastitis. The increased SCC of some milk samples with no presence of bacteria meant that the increase could have been caused by numerous other agents (viruses, fungi, or algae) or factors for mastitis in the dairy industry. [ABSTRACT FROM AUTHOR]

Solutions to practical optimal control problems (OCPs) may consist of control profiles that switch between control limits or assume values interior to their admissible set, either due to activation of inequality state path constraints or existence of singular control arcs. Abrupt switches in the control (i.e., bang-bang control) jeopardizes the numerical solution of OCPs unless care is taken to isolate precise time transition points where sharp switches occur (excluding the chattering phenomenon). We propose a novel control regularization method, called Bang-Bang Singular Regularization (BBSR), based on L2 norm-based regularization. We present an analysis on the L2 norm-based regularization at two levels: 1) its connection to trigonometric regularization and 2) its ability to approximate regular and singular control arcs. The utility of the method is demonstrated in solving three classes of trajectory optimization problems: 1) space minimum-fuel low-thrust trajectories with bang-bang thrust profiles, 2) the Goddard rocket problem with its known bang-singular-bang control structure, and 3) minimum-time spacecraft reorientation with both bang-bang and second-order singular arcs. The results demonstrate the utility of the BBSR method in approximating extremal control profiles that may consist of pure regular and/or mixed regular and singular control arcs.

The aim of the present paper is to describe the teaching grammar process in Iraqi secondary schools based on the Communicative Approach (CA) with reference to teacher’s experience and the difficulties that the teachers face during teaching the class. Teaching grammar in Iraqi secondary schools is the dominant content in the syllabus and is preferred to other skills. Additionally, teaching grammar in Iraqi secondary schools using other methods, such as: Grammar-Translation method (GTM) which is considered as the principal method, ‘Direct method’ (DM) and ‘Indirect method’ (IM) enable teachers to meet what learners need during learning the grammatical structures.

Background: In vivo Hounsfield Unit (HU) values have traditionally been determined using direct CT image measurements. These measurements are dependent on the window/level used to examine the CT image and the individual conducting the fat tissue tracing. Methods: Using an indirect method, a new reference interval (RI) is proposed. A total of 4000 samples of fat tissues were collected from routine abdominal CT examinations. A linear regression equation was then calculated using the linear part of the cumulative frequency plot of their average values. Results: The regression function for total abdominal fat was determined to be y = 35.376*x − 123.48, and a 95% confidence RI of −123 to −89 was computed. A significant difference of 3.82 was observed between the average fat HU values of visceral and subcutaneous areas. Conclusions: Using statistical methods and the in vivo measurements of patient data, a series of RIs were determined for fat HU that is consistent with theoretical values. [ABSTRACT FROM AUTHOR]

Background: The availability of a reliable reference interval is crucial for clinical decision-making. Correctly defined reference intervals for different age groups are currently unavailable for many parameters. Our study aimed to determine the complete blood count reference intervals in our region from newborn to geriatric ages with an indirect method. Methods: The study was carried out at Marmara University Pendik E&R Hospital Biochemistry Laboratory between January 2018 and May 2019 using the laboratory information system data. The complete blood count (CBC) measurements were performed by Unicel DxH 800 Coulter Cellular Analysis System (Beckman Coulter, FL, USA). A total of 14,014,912 test results belonging to infants, children, adolescents, adults, and geriatric ages were collected. We analyzed 22 CBC parameters, and an indirect method was used for reference interval determination. Data were analyzed according to the Clinical and Laboratory Standards Institute (CLSI) C28-A3 guideline for defining, establishing, and verifying reference intervals in the clinical laboratory. Results: We have established reference intervals from newborn to geriatric ages for 22 hematology parameters [hemoglobin (Hb), hematocrit (Hct), red blood cell (RBC), mean red cell volume (MCV), mean red cell hemoglobin (MCH), mean red cell hemoglobin concentration (MCHC), red cell distribution width (RDW), white blood cell (WBC) count, WBC differentials, including percentages and absolute counts, platelet count, platelet distribution width (PDW), mean platelet volume (MPV) and plateletcrit (PCT)]. Conclusions: Our study showed that reference intervals established with data obtained from clinical laboratory databases are comparable to those created using direct methods. [ABSTRACT FROM AUTHOR]

The main problem with counting vehicles in rest areas in Europe and America is the overflowing of parking lots in the rest areas. Thus it is impossible to count parked vehicles with traditional, direct methods, which use cameras and Lidar (light detection and ranging) to detect the presence of vehicles in individual parking spots. The solution to this problem may be an indirect method which uses cameras to count the vehicles entering and leaving the rest area and which sorts the vehicles into categories. This article introduces a method for determining car park occupancy in rest areas using indirect measurement and evaluates the uncertainty of this method for determining the occupancy. This indirect method counts the vehicles entering and leaving the car park and sorts the vehicles into categories. The difference between the number of vehicles that entered and the number of vehicles that left in a given time gives the number of vehicles occupying the car park, i.e., the parking space demand for a given time. This demand will vary over time. In order to register the vehicles entering and leaving, mains-free supply video cameras were installed next to the entrance and exit. The counting and categorizing could be conducted organoleptically, semi-automatically, or using an image computer analysis using artificial intelligence networks. Because the difference between the number of vehicles entering and leaving is calculated over a long period, a relative error (regarding car park capacity) might be grave even when the counting errors are minor. The authors will show how the certainty of this indirect counting method can be improved. [ABSTRACT FROM AUTHOR]

When obtaining new cultivars or monitoring the nutritional composition of lettuce, new techniques are necessary given the high cost and time required to conduct laboratory analyses of plant composition by conventional methods. The objective of this study was to evaluate different vegetation indices for the estimation of anthocyanin, chlorophyll, and carotenoids in mini-lettuce genotypes with different leaf colors and different typologies from red, green, and blue (RGB) images. The contents of pigments were evaluated in 15 lettuce genotypes, in addition to the soil plant analysis development (SPAD) index and vegetation indices in the visible range. The variability among genotypes was confirmed by the Scott-Knott test (p < 0.05) and multivariate analysis. Linear regressions were obtained between the green leaf index (GLI) and leaf pigments. GLI was a good predictor for estimating the contents of anthocyanin (r = −0.83; r2 = 0.75), carotenoid (r = −0.59; r2 = 0.43), chlorophyll a (r = −0.69; r2 = 0.48), chlorophyll b (r = −0.62; r2 = 0.39), and total chlorophyll (r = −0.77; r2 = 0.65) in red and green mini-lettuce. The high-performance phenotyping technique can be used to evaluate leaf pigments in breeding programs, as well as in crops for monitoring biofortification levels in lettuce. [ABSTRACT FROM AUTHOR]

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In this paper, the finite thrust nonplanar transfer and cooperative rendezvous are investigated. The indirect method is adopted in the optimization process. The energy-optimal to fuel-optimal continuation is performed by using the homotopy method. An initial guess generator (IGG) is designed based on a simplified dynamical model to overcome the difficulty in providing the initial guess. Some reasonable simplifications on the dynamical model are applied based on the near-circular near-coplanar transfer. The initial guess can be obtained by analytically solving a system of linear equations. Therefore, the IGG has high computational efficiency. Moreover, the terminal time and state are estimated by IGG to deal with the cooperative rendezvous problem. Numerical examples are presented and the validity of the "IGG-Homotopy" combined algorithm is verified. [ABSTRACT FROM AUTHOR]

The types of additive technologies and the prospects for their use in the fabrication of products from silicon carbide ceramic materials are considered. The most popular for obtaining parts of complex configurations are additive technologies such as stereolithography, photocuring, inkjet printing, layer-by-layer 3D printing by extrusion of 'inks,' three-dimensional printing, selective laser sintering, selective laser melting, lamination method, layer-by-layer deposition method. [ABSTRACT FROM AUTHOR]

Recent decades have witnessed a rise in interest in bridge health monitoring utilizing the vibrations of passing vehicles. However, existing studies commonly rely on constant speeds or tuning vehicular parameters, making their methods challenging to be used in practical engineering applications. Additionally, recent studies on the data-driven approach usually need labeled data for damage scenarios. Still, getting these labels in engineering is difficult or even impractical because the bridge is typically in a healthy state. This paper proposes a novel, damaged-label-free, machine-learning-based, indirect bridge-health monitoring method named the assumption accuracy method (A 2 M). Initially, the raw frequency responses of the vehicle are employed to train a classifier, and K-folder cross-validation accuracy scores are then used to calculate a threshold to specify the bridge's health state. Compared to merely focusing on low-band frequency responses (0–50 Hz), utilizing full-band vehicle responses can significantly improve the accuracy, meaning that the bridge's dynamic information exists in the higher frequency ranges and can contribute to detecting bridge damage. However, raw frequency responses are generally in a high-dimensional space, and the number of features is much greater than that of samples. To represent the frequency responses via latent representations in a low-dimension space, appropriate dimension-reduction techniques are therefore, needed. It was found that principal component analysis (PCA) and Mel-frequency cepstral coefficients (MFCCs) are suitable for the aforementioned issue, and MFCCs are more damage-sensitive. When the bridge is in a healthy condition, the accuracy values obtained using MFCCs are primarily dispersed around 0.5, but following the occurrence of damage, they increased significantly to 0.89–1.0 in this study. [ABSTRACT FROM AUTHOR]

Sensitivity analysis is applied to ship manoeuvring mathematical models as a means of dealing with model uncertainties, and often leads to model simplifications. A rather standard 3DOF manoeuvring model was tuned with the available results of full-scale trials of a naval combatant and was further used as the reference model for sensitivity analysis. The present research was based on multiple perturbed simulations of the turning, zigzag and spiral manoeuvres. A salient feature of the present study is that the perturbations were applied to the total hydrodynamic forces and moments as well as separately to their characteristic parts, i.e., to the linear and nonlinear single-variable and coupled components. Another special feature is that the deviations of the perturbated responses were estimated not only considering the standard manoeuvring performance indices, but also through application of the Euclidean metric directly to the time histories and to the spiral curve. The performed analysis permitted the sensitivity of the model to be traced to various parameters and groups thereof. It was established that the highest sensitivity of the model was to linear and some nonlinear multivariable parameters, and the Euclidean metric permitted a more detailed analysis than that based only on standard discrete manoeuvring indices. The obtained results are expected to be useful in the application of system identification methods to typical inherently stable fast surface-displacement ships. [ABSTRACT FROM AUTHOR]