Four-component Model Research Articles

Valley-polarized edge plasmons in graphene p–n junctions with pseudomagnetic fields

Abstract Owing to the inherent characteristics of collective excitations in graphene, electrical control of edge plasmons is highly desirable for nanoplasmonic applications. This study investigates valley-polarized edge pseudomagneplasmons in a graphene p–n junction subjected to a strain-induced pseudomagnetic field. A four-component hydrodynamic model is employed and solved via the Wiener–Hopf method, revealing the coexistence of three plasmon modes, including counterpropagating acoustic edge modes, gapless topological edge states, and zero modes. The valley polarization, as determined from the numerically exact solution, is stronger than that predicted by the approximate models. Notably, the confinement of edge plasmons at the graphene p–n junction significantly exceeds that at the graphene/vacuum interface, possibly because of the electron–hole attraction. Furthermore, gate-controlled subwavelength confinement is successfully achieved by applying an appropriate gate voltage, thereby highlighting a unique and promising attribute of edge pseudomagnetoplasmons in graphene p–n junctions.

Identification of oil contamination in process water using fluorescence excitation emission matrix (FEEM) and parallel factor analysis (PARAFAC).

Fuel oil is widely used within Eskom, a power generation company in South Africa. Eskom's coal-fired power stations use up to 30,000 L of fuel oil per hour during a cold start-up, a consequence of which results in oil leaks to the dams. Oil contamination in water treatment plants causes irreversible membrane fouling, requiring costly replacement. This research work focused on the development of a rapid method for the identification of low concentrations of the water-soluble oil component fraction of crude fuel oil. For the developed method, known volumes of the water-soluble fraction of crude oil were spiked into various matrices of process water. FEEMs were collected using the patented HORIBA Aqualog spectrometer and data were modelled with PARAFAC. The results were well described with a four-component model, which included an oil component and three natural organic matter components, with a split-half validation match of 90%. The oil component was verified using linear regression of the PARAFAC component scores yielding an R2 value of 0.98. From the scores, a qualitative pass/fail test was developed such that process water can be analysed and subjected to the model to indicate the presence of oil contamination beyond a damaging threshold.

The Influence of Crucibles of Experience in Moral Development & Psychology of Public Relations Exemplars

ABSTRACT This study conducted life story interviews with 40 members of the PRSA College of Fellows to examine the influence of crucibles (i.e. trials, challenges or growth opportunities) in the moral development and psychology of public relations exemplars. The outcomes were the development of an illustration of their moral and leader development journey drawing on Rest’s four-component model of ethical decision making, and a moral psychology profile of the key characteristics of public relations exemplars. The profile that emerged is that of leaders who exemplify moral courage, resilience, generosity, genuine care about others and are willing to listen and learn. When they faced trials, they emerged stronger and stayed true to their values and character.

Relationship between learners' L2 Motivational Self System and parental investment behavior in learners' English learning.

Students' motivation and learning behavior are significantly impacted by parents' participation and investment. It has been demonstrated that parental investment behavior could exert a direct effect on students' L2 Motivational Self System (L2MSS) mediated by parental investment belief. Nevertheless, the relationship between components of parental investment behavior and students' language learning motivation remains a topic necessitating further scholarly investigation. In response to this gap, we conducted a quantitative study involving a survey of 900 high school students to explore the relationship between students' English learning motivation, as conceptualized by the L2 Motivational Self System and parental investment behavior based on a four-component model. The findings in this study indicated that high school students exhibited moderate levels of L2MSS and relatively low levels of parental investment behavior. Moreover, students' L2MSS was found to have a significant positive correlation with the global parental investment behavior, with parental emotional investment behavior emerging as a positive predictor of high school students' L2MSS. These results underscore the importance of parental provision of sufficient economic, relationship, knowledge, and emotional support in cultivating a nurturing and supportive familial context conducive to the development of students' positive future selves.

When failure is not an option: a police firearms training concept for improving decision-making in shoot/don't shoot scenarios.

Sometimes, policing requires a quick and correct assessment of potentially hazardous situations. The training of tactical gaze control and visual attention, and its positive impact on efficient shoot/don't shoot decisions in police cadets' use of firearms has recently been demonstrated. On this basis, we designed an individual videobased police firearms training that was grounded on the Four-Component Instructional Design Model (4C/ID). We shifted toward an individual blended learning approach where we applied an intervention training focused on situational awareness, tactical gaze control, and visual attention. In a preregistered lab experiment, N = 45 senior police officers were randomly allocated to the intervention training or an active control training that resembled a traditional police firearms training. Both groups watched a self-produced educational video before proceeding to the practical training in our indoor firing range. In a pre- and post-test, they engaged in realistic shoot/don't shoot video scenarios. Both groups did very well regarding decision-making, the optimal muzzle position, and the tactical conduct to keep both eyes open before shooting. Although both groups performed on a comparable level in the pre-test's shoot scenarios, the intervention group significantly improved their response times and time until the first hit. Overall, we were able to provide an adapted, didactically based police firearms training that supplements current standards. We demonstrated that experts are still susceptible to innovative training concepts and therefore substantiate the recommendation to devote more attention to approaches that emphasize the importance of situational awareness, tactical gaze control, and visual attention in police firearms training.

Geospatial Variability of Fluorescent Dissolved Organic Matter in Urban Watersheds: Relationships with Land Cover and Wastewater Infrastructure.

We investigated the fluorescent dissolved organic matter (FDOM) composition in two watersheds with variable land cover and wastewater infrastructure, including sanitary sewers and septic systems. A four-component parallel factor analysis model was constructed from 295 excitation-emission matrices recorded for stream samples to examine relationships between FDOM and geospatial parameters. The contributions of humic acid- and fulvic acid-like fluorescence components (e.g., C1, C2, C3) were fairly consistent across a 12 month period for the 27 sampling sites. In contrast, the protein-like fluorescence component (C4) and a related ratiometric wastewater indicator (C4/C3) exhibited high variability in urban tributaries, suggesting that some sites were impacted by leaking sewer infrastructure. Principal component analysis indicated that urban areas clustered with impervious surfaces and sanitary sewer density, and cross-covariance analysis identified strong positive correlations between C4, impervious surfaces, and sanitary sewer density at short lag distances. The presence of wastewater was confirmed by detection of sucralose (up to 1,660 ng L-1) and caffeine (up to 1,740 ng L-1). Our findings not only highlight the potential for C4 to serve as an indicator of nearby, compromised sanitary sewer infrastructure, but also suggest that geospatial data can be used to predict areas vulnerable to wastewater contamination.

Digital Literacy and Islamic Sharia Values as A New Perspective of Preventing OGBV

This research aims to explore the digital literacy position of students using social media in Aceh and see its relation to the issue of OGBV as victims and bystanders. This research also investigates the relationship between digital literacy, OGBV, and the role of Sharia Law in Aceh, which may provide a new perspective for preventing OGBV in Indonesia, considering the paucity of previous studies correlating those three aspects. This research utilized the concept of Digital Literacy created by Paul Gilster and used the Four-Component Digital Literacy Model developed by Alexander V. Sharikov. This research was conducted using a qualitative approach. Researchers conducted in-depth interviews with nine students and analyzed them using Thematic Analysis. The results revealed that most participants do not have a knowledge base about OGBV, which has implications for their digital literacy capital, especially in identifying various OGBV variants and how to protect personal data on social media. In addition, Islamic law influences participants' digital literacy in dealing with OGBV. However, participants' knowledge of Sharia law values regarding safe and responsible digital interaction patterns has yet to develop comprehensively.

Motion acquisition of gait characteristics one week after total hip arthroplasty: a factor analysis

IntroductionClinical gait analysis can be used to evaluate the recovery process of patients undergoing total hip arthroplasty (THA). The postoperative walking patterns of these patients can be significantly influenced by the choice of surgical approach, as each procedure alters distinct anatomical structures. The aim of this study is twofold. The first objective is to develop a gait model to describe the change in ambulation one week after THA. The secondary goal is to describe the differences associated with the surgical approach.Materials and methodsThirty-six patients undergoing THA with lateral (n = 9), anterior (n = 15), and posterior (n = 12) approaches were included in the study. Walking before and 7 days after surgery was recorded using a markerless motion capture system. Exploratory Factor Analysis (EFA), a data reduction technique, condensed 21 spatiotemporal gait parameters to a smaller set of dominant variables. The EFA-derived gait domains were utilized to study post-surgical gait variations and to compare the post-surgical gait among the three groups.ResultsFour distinct gait domains were identified. The most pronounced variation one week after surgery is in the Rhythm (gait cycle time: +32.9%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$+32.9\\mathrm{\\%}$$\\end{document}), followed by Postural control (step width: +27.0%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$+27.0\\mathrm{\\%}$$\\end{document}), Phases (stance time: +11.0%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$+11.0\\%$$\\end{document}), and Pace (stride length: − 9.3%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$9.3\\%$$\\end{document}). In postsurgical walking, Phases is statistically significantly different in patients operated with the posterior approach compared to lateral (p-value = 0.017) and anterior (p-value = 0.002) approaches. Furthermore, stance time in the posterior approach group is significantly lower than in healthy individuals (p-value < 0.001).ConclusionsThis study identified a four-component gait model specific to THA patients. The results showed that patients after THA have longer stride time but shorter stride length, wider base of support, and longer stance time, although the posterior group had a statistically significant shorter stance time than the others. The findings of this research have the potential to simplify the reporting of gait outcomes, reduce redundancy, and inform targeted interventions in regards to specific gait domains.

Forecasting oil displacement in clay-rich reservoirs using water injection with varying mineral compositions

On the basis of a two-phase four-component fluid filtration model, mathematical modeling of a clay oil-bearing reservoir has been performed, which allows taking into account all physico-chemical processes occurring when exposed to water of various mineral composition, and on its basis to assess the possibility of restoring the reduced permeability of the reservoir due to the injection of water with low mineralization on the basis of treatment with a clay stabilizer. It has been established that the treatment of the layer with the optimal amount of clay stabilizer provides a significant intensification of oil production.

Microcosmic mechanism of asphalt-aggregate interface adhesion failure under freeze-thaw cycles based on molecular dynamics

ABSTRACT In order to investigate the micro-mechanisms of adhesive failure at the asphalt-aggregate interface under freeze-thaw cycling, this study presents a novel model for freeze-thaw cycling of asphalt mixtures constructed using molecular dynamics. The model is employed to explore the micro-mechanisms of adhesive failure between asphalt and aggregate surfaces under freeze-thaw cycling conditions. Utilising the four-component model of asphalt, asphalt molecules were constructed, with silicon dioxide and calcium carbonate chosen to represent acidic and alkaline aggregates, respectively. Subsequently, an asphalt-aggregate-water freeze-thaw cycling model was developed. Building upon this foundation, the variations in interface interactions between asphalt and the two types of minerals were analysed under the same freeze-thaw cycling conditions but differing freeze-thaw cycle counts. This analysis was conducted through the examination of Radial Distribution Function (RDF), water molecule coordination numbers, and hydrogen bond quantities at the interfaces between asphalt and the two mineral types. The research findings indicate that acidic aggregates exhibit a greater affinity for water molecules compared to alkaline aggregates. Hydrogen bond interactions exist between aggregates and water molecules, with the hydrogen bond energy being greater than the interactions between asphalt molecules and aggregate surfaces. The cohesive energy decreases with an increasing number of freeze-thaw cycles, leading to a gradual reduction in asphalt viscosity and facilitating the detachment of asphalt from the aggregate surface. Consequently, acidic aggregates tend to absorb water molecules more readily, and water can lower the viscosity of asphalt molecules, ultimately resulting in the macroscopic delamination of asphalt from the aggregate surface. These research outcomes provide valuable theoretical guidance for a deeper exploration of the adhesive failure mechanisms in asphalt-aggregate interactions.

Exploring the determinants of (un)ethical decision-making among accountants using PLS-SEM: a developing country context

PurposeThis study aims to examine the determinants of ethical decision-making (EDM) of professional accountants in Sri Lanka, drawing on Rest’s (1986) four-component EDM model. The level of corporate collapses and fraud, coupled with the high level of corruption in Sri Lanka, has highlighted the importance and the timely nature of this research in the EDM processes of Sri Lankan accountants.Design/methodology/approachData was collected from a sample of 315 accountants through a questionnaire survey that included four written ethical vignettes and was analysed using partial least square-structural equation modelling techniques.FindingsThe findings revealed a significant relationship between ethical awareness and ethical judgement, providing support for Rest’s model. However, the study does not support Rest’s model on the direct relationship between ethical judgement and ethical intention. Intrinsic religiosity and moral intensity significantly influenced the ethical awareness of accountants. Several determinants including accountants’ age, education, intrinsic religiosity, organisational ethical culture, familiarity with the professional ethical code and moral intensity influenced ethical judgement. However, the findings did not report any significant relationships between the study’s variables and ethical intention.Originality/valueThe study adds to the existing literature by providing a bigger picture of how various determinants work together in one EDM model and demonstrating that the EDM of accountants is multifaceted. The new finding on an insignificant relationship between ethical judgement and ethical intention implies that the Rest’s EDM process may be mediated and moderated by other constraints blocking accountants’ intention to act due to various pressures in a corrupt society, Sri Lanka, where accountants operate.

Four-component model of a child’s personality development: observation results

Four-component model of a child’s personality development: observation results

A Novel Polarization Scattering Decomposition Model and Its Application to Ship Detection

In polarimetric synthetic aperture radar (POLSAR), it is of great significance for civil and military applications to find novel model-based decomposition methods suitable for ship detection in different detection backgrounds. Based on the physical interpretation of polarimetric decomposition theory and the Lasso rule for sparse features, we propose a four-component decomposition model, which is composed of surface scattering (Odd), double-bounce scattering (Dbl), volume scattering (Vol), and ±45° oriented dipole (Od). In principle, the Od component can describe the compounded scattering structure of a ship consisting of odd-bounce and even-bounce reflectors. Moreover, the pocket perceptron learning algorithm (PPLA) and support vector machine (SVM) are utilized to solve the linear inseparable problems in this study. Using large amounts of RADARSAT-2 (RS-2) fully polarized SAR data and AIRSAR data, our experimental results show that the Od component can make a great contribution to ship detection. Compared with other conventional decomposition methods used in the experiments, the proposed four-component decomposition method has better performance and is more effective and feasible to detect ships.

Psychometric analysis of questionnaire of cyberbullying and aggression on the Internet

Introduction. The socialization of a modern teenager is inevitably connected with digital skills and communication on the Internet. The Internet itself acts as a cognitive technology that has many benefits and opportunities for cognitive development and education. At the same time, a child's activity on the Internet can lead to a number of risks, including a collision with aggression in the online space. With the development of information technology, a special type of bullying is being formed – cyberbullying. Often, Russian scientific articles do not provide data on the psychometric qualities of cyberbullying questionnaires and questionnaires used in the study. The content of the cyberbullying questionnaire requires constant updating and clarification of behavioral manifestations.Materials and Methods. The paper describes the results of a psychometric test of questionnaire of cyberbullying and aggression on the Internet. The questionnaire consists of 18 direct questions and is designed to define the experience of cyberbullying. Psychometric features of the Survey were tested among sampled 312 respondents, including girls (n=231) and boys (n=81) at the age of 13-22.Results. An exploratory factor analysis determines a four-component model of the Survey: cybervictimity, cyberagression, negative emotions from online communication and a factor of adults’ assistance. The Survey’s scales were verified for their reliability: Cronbach’s alpha coefficient of scales’ internal consistence is 0.712 – 0.779. The Surveys’ scales are reliably interconnected by their correlational ties from 0.50 to 0.60.Discussion and Conclusions. Convergent validity of the Cyberbullying Survey is examined: this revealed reliable correlational ties with all CIAS scales, as well as with personal features of irascibility, proneness to conflicts, suspiciousness, and negative aggression on the whole (Personal Aggression and Proneness to Conflicts by E.P. Ilin and P.A. Kovalev). The obtained results prove that the Survey under analysis is a reliable psychometric instrument for studying cyberbullying which could be applied for scientific purposes and in practice.

Quantitative evaluation of The Imagineerium education project by students: Introducing the trowsdale index of confidence in experiential learning

The Imagineerium is an arts and engineering based curriculum project designed to enhance student confidence in learning. This study reports on the development of the Trowsdale Index of Confidence in Experiential Learning, an instrument designed to conceptualise and operationalise a four-component model of confidence in experiential learning appropriate for upper primary school students, embracing confidence in creativity, confidence in competence, confidence in collaboration, and confidence in learning. Data provided by 140 9- to 10-year-old students both before and after participating in the 10-week programme, demonstrated a significant increase in scores on this measure at time two, although there was no increase in scores on a control variable hypothesised not to be influenced by the intervention.

A four-component mixing model reveals snowpack melting as early as March during the 2019 hydrological year in the Upper Ganga Basin

Ice and snow meltwater are important components of the glacier-fed Himalayan rivers that control the seasonal streamflow pattern. With the ongoing global warming, there remains significant uncertainty regarding how melting Himalayan glaciers will impact the water runoff. Here, we quantified the rainwater, ice meltwater, snow meltwater, and groundwater flow in the river using a δ18O, d, and Cl- -based 4-component hydro-geochemical mixing model. At a weekly resolution, we measured the stable water isotopes (18O/16O and 2H/1H, expressed as δ18O and δD), Cl- and Na+ near the river Alaknanda mouth, in the Upper Ganga Basin over one year (2018–2019). The weekly scale time-series geochemical record captured the subtle variability of ice and snow meltwater flow in the Alaknanda River. The two most significant observation was (i) an onset of snow meltwater was observed as early as in March during the study period contrary to our present understanding that the onset of snow meltwater usually happens in April, and (ii) a significant increase in ice and snow meltwater flow during the peak monsoon season. The early onset of snow meltwater runoff in the Himalayan rivers could be an important concern as this could potentially reduce the flow of snow meltwater during the early summer months when water demand is highest due to intense agricultural activities in the mountainous region. Similarly, an increase in ice meltwater runoff in the monsoon season increases the risks of major flood events. Since weekly scale time-series data of ice meltwater, snow meltwater, rainwater, and groundwater flow in glacier-fed Himalayan rivers over the entire hydrological year was largely missing, this study provides an important dataset to better understand the year-long dependency of the Himalayan rivers on the glaciers critical to improving the accuracy and predictive power of hydrologic models.

Testing models for the compositions of chondrites and their components: III. CM chondrites

In continuation of our comprehensive study of the carbonaceous chondrites, we here present data for the CM chondrites. Our study’s aim is to determine the abundances and the average elemental compositions of the major and minor chondritic components. The overarching goal has been to explore the fundamental question of whether chondrules and matrix are complementary, i.e., genetically related, or if these major chondritic components evolved separately before accretion as in the four-component model.Using point-counting and electron microprobe analyses, we investigated the most primitive CMs known to date: Asuka (A) 12169 (CM3.0), A 12236 (CM2.9) and Paris (CM2.7–2.9). Despite their primitiveness, however, none of the samples is completely devoid of signs of terrestrial and/or parent body alteration. For instance, we found evidence for the mobilization and heterogenous redistribution of Ca, as well as for the leaching of Al from chondrules and redeposition into matrix. There is also a trend of the Ca and Al abundances in both, chondrules and matrix, to become increasingly heterogeneous with increasing parent body alteration. We were, therefore, unable to test chondrule-matrix complementarity and the four-component model using Al and Ca. Assuming that Mg and Si are insignificantly affected by alteration and that the Mg/Si ratios of the components in A 12169 are unaltered, our data indicate the pre-accretionary loss from matrix of ∼12 wt% forsterite (matching our results for the primitive COs and CRs) and the addition of a roughly similar amount of forsterite to the chondrules (contrary to our results for the COs and CRs). These results are inconsistent with the four-component model but, based on the matrix/chondrule abundance ratio, complementarity predicts that the addition of forsterite to chondrules should have been significantly higher. This and the possibility that A 12169 component compositions have been modified to some degree means that our results do not unambiguously favor either model.

Developing media literacy as complex learning in secondary schools: the effect of 4C/ID learning environments

ABSTRACT Background: Today, the importance of teaching media literacy in education has been highlighted, and the need for effective instructional design in this field has received more attention. This research attempts to investigate the effect of the Four-Component Instructional Design (4C/ID) model on developing media literacy. Method: This study employs a quasi-experimental pre-test-post-test design. The research subjects were recruited from tenth-grade students at secondary schools in Mashhad, Iran. A total of 30 students were selected as the sample using the convenience sampling method. Fifteen students were placed in the experimental group, and the rest were placed in the control group. Result: Statistical analysis (ANCOVA, MANCOVA & MANOVA) showed that designing instruction based on the complex-learning model (4C/ID) improved learning outcomes, critical thinking, and conscious interaction with the media. Conclusion: Acquiring media literacy competence is a complex learning process. Based on the results of this study, the four-component instructional design model (4C/ID) can promote the development of media literacy skills in students.

Evaluating Alternate Methods of 4D-Var Data Assimilation in a Coupled Hydrodynamic—Four-Component Biogeochemical Model of the California Current System

Assimilating biogeochemical (BGC) data into ocean models using traditional four-dimensional variational data assimilation (4D-Var) includes the technical challenge of constructing tangent-linear (TLM) and adjoint (ADJ) models corresponding to the non-linear BGC model. This hurdle can be time-consuming, particularly for non-linear BGC models experiencing active development, with regular updates to functional types or representation of key BGC processes. We evaluate two alternate approaches that greatly simplify TLM and ADJ construction and eliminate the need for code updates when the underlying, non-linear BGC model changes. One form of model-reduced data assimilation represents BGC interactions as a linear combination of orthogonal modes; we use empirical orthogonal functions and refer to this as the BioEOFs method. The second approach treats BGC variables as passive tracers that experience advection and diffusion by TLM and ADJ physics over an assimilation cycle, but are biochemically inactive. We evaluate the efficacy of these methods in a realistically configured, data-assimilative implementation of the Regional Ocean Modeling System with a simple nutrient–phytoplankton–zooplankton–detritus (NPZD) BGC model for the U.S. west coast. In a series of sequential data-assimilative model cycles, observations of temperature, salinity, sea-level anomaly, and phytoplankton biomass constrain the modeled state over the period spanning January–June 2019. We perform the assimilation in both physical and logarithmic-transformed space and compare results of the two approximate methods to traditional 4D-Var using TLM and ADJ models with BGC processes corresponding explicitly to the BGC model. While the full-adjoint 4D-Var results in the best correction to phytoplankton fields for analyses and forecasts, the BioEOFs and passive-tracer approaches also significantly reduce the model-observation misfit compared to a non-assimilative run and do so at reduced computational expense. The passive tracer performs generally better than BioEOFs, whose corrections exhibit large-scale structure across the domain. While the most accurate state estimate will result from development and application of the full TLM and ADJ, the log-transformed passive-tracer approach may be a viable alternative for performing BGC 4D-Var for state estimation when a full-adjoint option is not yet available.

Optimal Maintenance Schedule for a Wind Power Turbine with Aging Components

Wind power is one of the most important sources of renewable energy available today. A large part of the cost of wind energy is due to the cost of maintaining wind power equipment. When a wind turbine component fails to function, it might need to be replaced under circumstances that are less than ideal. This is known as corrective maintenance. To minimize unnecessary costs, a more active maintenance policy based on the life expectancy of the key components is preferred. Optimal scheduling of preventive maintenance activities requires advanced mathematical modeling. In this paper, an optimal preventive maintenance algorithm is designed using the renewal-reward theorem. In the multi-component setting, our approach involves a new idea of virtual maintenance that allows us to treat each replacement event as a renewal event even if some components are not replaced by new ones. The proposed optimization algorithm is applied to a four-component model of a wind turbine, and the optimal maintenance plans are computed for various initial conditions. The modeling results clearly show the benefit of PM planning compared to a pure CM strategy (about 30% lower maintenance cost).