Workload Levels Research Articles

Variation of Pilots’ Mental Workload Under Emergency Flight Conditions Induced by Different Equipment Failures: A Flight Simulator Study

Pilots’ excessive mental workload could reduce their ability to perform concurrent tasks during emergency flights, which is one of the most critical aviation safety concerns. Several past efforts have attempted to investigate the underlying issues, but all had limited success owing to the challenge of collecting representative data under realistic operating conditions. This study aimed to address this challenge by conducting a flight simulator study involving a comparatively large number of participants, who were pilot cadets with flight experience, and using noninvasive functional near-infrared spectroscopy (fNIRS) to collect the pilots’ brain activity data. Pilots’ subjective ratings and brain activity records were collected over a total of 75 simulated flights under three subtask scenarios comprising different equipment failures. A statistical analysis was carried out on the subjective ratings and on the changes observed in the saturation of the oxyhemoglobin (ΔOxyHb) of individual fNIRS channels. The mental workload of the pilots was classified using a support vector machine hierarchical combination classifier, focusing on the question of whether it is feasible to classify pilots’ mental workload using brain activity signals (i.e., ΔOxyHb). The results suggested that the pilots’ mental workload levels were highly associated with the ΔOxyHb measures as well as with the activities of different brain regions, including the prefrontal-, motor-, and occipital cortex. The findings from this study could provide a reference for optimizing pilot training systems and improving pilot performance during emergency flight operations.

Fast & scrupulous: Gesture-based alarms improve accuracy and reaction times under various mental workload levels. An ERSP study

In high-risk environments, fast and accurate responses to warning systems are essential to efficiently handle emergency situations. The aim of the present study was twofold: 1) investigating whether hand action videos (i.e., gesture alarms) trigger faster and more accurate responses than text alarm messages (i.e., written alarms), especially when mental workload (MWL) is high; and 2) investigating the brain activity in response to both types of alarms as a function of MWL. Regardless of MWL, participants (N = 28) were found to be both faster and more accurate when responding to gesture alarms than to written alarms. Brain electrophysiological results suggest that this greater efficiency might be due to a facilitation of the action execution, reflected by the decrease in mu and beta power observed around the response time window observed at C3 and C4 electrodes. These results suggest that gesture alarms may improve operators’ performances in emergency situations.

Mediating role of educational environment in the relationship between workload and generic skills of nursing students in Vietnam

Students’ learning experiences are considered useful indicators to evaluate the effectiveness of teaching in tertiary education. With limited theory-driven research, this study aimed to examine whether the educational environment is able to mediate the relationship between student workload and generic skills. A cross-sectional study was conducted among 1347 nursing students in ten nursing schools across Vietnam from November 2021 to January 2022. The results showed that the total score of the students’ workload and the generic skills were 3.25 ± 0.59 and 3.84 ± 0.56 (possible score: 1-5), respectively. Students were at an “agree” level with statements like “the sheer volume of work to be got through in this course means you can’t comprehend it” and “as results of doing this course, I feel more confident about tackling unfamiliar problem”. Most nursing students rated the educational environment at levels of “more positive educational environment” (N=1018, 75.58%), with a total score of 120.75 ± 20.78 (possible score: 0-200). The educational environment was identified as a mediator in the relationships between the workload and the generic skills. The direct effect on workload was -0.00035 which was not significant (p=0.987) with the generic skills. The indirect effect of workload that passes through the educational environment was -0.07 and is also statistically significant, at p= 0.002. As such, the study suggests that, to enhance students’ generic skills, it is necessary to instruct students in efficient learning strategies to help them manage their academic workload, particularly during unexpected situations such as the COVID-19 pandemic. Additionally, despite the occurrence of a high level of student workload, nursing schools could focus on efficient tactics and interventions to improve the educational environment, which subsequently helps to improve students’ outcomes.

Analysis of the Heart Rate of Operators of Forwarding Machines during Work Activities

The aim of this work was to determine the dependence of the heart rate of operators of forwarding machines on the activities performed during the working day within the framework of timber forwarding and to compare individual activities in terms of the level of physical workload. For this purpose, the work shift of operators carrying out timber forwarding was divided into individual activities: driving, maintenance, forwarding, and break. During these work activities, the heart rate of each operator was taken for subsequent evaluation. A portable device, a Garmin smartwatch, was used to measure their heart rate. The results show that the highest pulse rates of the operators occurred during the maintenance of the entrusted machine, while the highest pulse fluctuations were recorded during forwarding. During this activity, the highest heart rate of the entire measurement process was recorded (132.0000 bpm), but also the lowest (42.0000 bpm). Furthermore, it was proven that both the operator and the activity he performs affect the pulse rate. The activities themselves did not differ from each other in only one of the six cases of comparison, specifically, between driving and forwarding.

Analysis of Physiological Workload in Tofu Production Process Based on Energy Recovery at Rest

UD. Koder is a manufacturing company that processes raw materials into finished products in Sidoarjo. The production process is one of UD's production processes. Koder is still with manual performance. Manual production processes with flexible body movements and a lot of physical loads still depend on the ability of workers and require human labor. The assessment of the level of physical workload of workers is not clear. The purpose of this study was to examine the categories of physical stress on workers in manual production processes using physiological methods. The method used is to measure heart rate at work and at rest, as well as evaluate worker psychology in the form of consideration of heart rate reserve (%HRR), cardiovascular load (%CVL), and energy expenditure factor (KE). The results showed that the amount of energy expenditure for each worker included Faris (7.0 Kcal/minute), Muit (4.7 Kcal/minute), Budi (4.4 Kcal/minute), Gito (4.9 Kcal/minute), Sudar (5.0 Kcal/minute), Dito (4.6 Kcal/minute), Joni (4.9 Kcal/minute) resulting in an item of average energy expenditure (5.1 Kcal/minute) where all workers were at a moderate level. The recommended improvement for production workers is that the rest time is 1 minute 27 seconds each time the process is continuous.

Relationship Of Workload To Employee Stress Levels In PT. Wahyu Pradana Binamulia Makassar

Background: Each job has a different level of difficulty, depending on how heavy the workload is. If a person is given a light workload, then it is not a problem because it can be solved easily, but it is different if the work is considered a heavy workload, of course it has its own impact on each individual from fatigue to the onset of stress. The purpose of this study was to determine the relationship between workload and employee stress levels in PT. Rev. Pradana Binamulia. Methods: This research is non-experimental with quantitative methods, the type used is cross sectional with analytical observational research design. The population used is employees who work in PT. Wahyu PradanaBinamulia as many as 600 people with the number of samples taken as many as 170 respondents. The research instruments used were questionnaires from O'Donnell and Eggemeier to measure workload, and a DASS (Depression Anxiety Stress Scale) questionnaire to measure stress levels. Results: Data analysis using the chi-square test and obtained results of p <0.01 with a meaningfulness level of 5% (α=0.05) means that there is a significant relationship between workload and stress levels of PT employees. Wahyu PradanaBinamulia Conclusion: Most employees face heavy workload besides the stress level experienced by the majority of employees heavy stress.

Air traffic control students’ aspiration levels distributions

This paper proposes an analysis of an air traffic control students’ survey describing self-assessment of their workload levels. The workload is defined as the number of aircraft simultaneously under control. The survey is performed over the gird with axes represented with aircraft number, their correspondent, and utility/satisfaction levels. The aspiration level values are calculated using workload differences. The safety background of risks in aviation activities is described. Risk and aspiration level links are highlighted. The aspiration level notion for the proposed research is inferred. Survey details and conditions are explained. The differences in four quarters at the workload charts specified by respondents are explained. The aspiration level parameters and basic statistics calculated for respondents are presented. Appropriate goodness-of-fit tests are performed with different sets of initially received answers. Whole samples and subsamples are considered. It is shown that for the full sample considered, the outlet removal provides significant increase of p-value, thus allowing to change the hypothesis approval status. Sub-samples list includes the whole sample without outlets and the whole sample aspiration level calculated for only positive values according to y-axis. Additionally, other values were considered. Namely regret values, i.e., the values on the descending half of the charts and a mixture of regret and aspiration level values in regard that is higher. Normal and exponential distribution significances are proven for the different options mentioned above. It is shown that the general chi-squared method provides the latter mixture to be insignificantly exponential, whereas specific Fisher’s test approves the significance of the data. The role of air traffic control students’ aspiration level in their estimation and possible education strategy personalization is described. The importance of human factor consideration during similar survey performance is once again proven. The connection of regret with aspiration level in a mixture is discussed. The conclusions on the results are provided. Further research directions are proposed.

Analysis of mental workload indicators among railway crossing guards in Yogyakarta City

Background: Mental workload is the workload which results from the performed works, is seen from the performed works, and develops cognitively (within mind). The mental activities are also dominated by the jobs with a high level of alertness, such as what is found among railway crossing guards. This study aims to analyze the mental workload indicators among railway crossing guards in Yogyakarta City. Method: The study was conducted using a qualitative descriptive approach. The guideline to conduct interviews and to measure mental workloads was NASA – TLX (National Aeronautics and Space Administration – Task Load Index), with the procedures consisting of weighting, rating, and calculation of mental workloads. The population was all of the railway crossing guards in Yogyakarta City consisting of as many as 32 respondents. Results: The results of the study showed that 26 respondents experienced a high level of mental workloads, 4 respondents experienced a moderately high level of mental workloads, and 2 respondents experienced an extremely high level of mental workloads (subjectively). Conclusion: The aspects of mental workloads elaborated in this study were Mental Demand (MD), Physical Demand (PD), Temporal Demand (TD), Performance (P), Frustration Level (FL), and Effort (E). The most influencing aspect on mental workloads of railway crossing guards was the Performance aspect, with a value of 5473, since this aspect required high responsibility for the job.

Subjective mental workload in Spanish emergency nurses. A study on predictive factors

Introduction: Mental workload refers to the cognitive or intellectual requirements that a worker is subjected to in a workday. The objective of the present work was to discover the subjective mental workload of nursing staff at Hospital Emergency Units, and its relationship with sociodemographic, work, environmental factors at the workplace, and personality variables. Method: A quantitative, descriptive, observational, and crosssectional study was conducted with 201 emergency nurses from 13 different provinces in Spain. Each participant completed 5 questionnaires (sociodemographic, work conditions, environmental conditions, personality, and subjective mental workload). Descriptive statistics were obtained, and Pearson’s correlations and multivariate models (multiple linear regression) were performed. Results: The nurses had medium to high levels of mental workload. The environmental conditions had a direct relationship with the mental workload, especially with respect to noise and lighting. The participants obtained high scores in kindness, responsibility, openness/intellect, and extraversion. Positive and statistically significant relations were found between neuroticism and mental workload. Being female, older, and having stable employment or a permanent contract were associated with a greater mental workload of emergency nurses. Conclusion: The domain of neuroticism personality, and the hygienic conditions in the workplace were the predictors with the most weight in the model. This study could be useful for defining aspects that need to be considered for the well-being of emergency nurses, such as lighting conditions or environmental noise in the workplace. It also invites reflection on the influence of personal factors (age, gender, personality) and work factors (type of contract, professional experience) on the mental workload of emergency nurses.

IDEA - TOWARDS AN INTERACTIVE TOOL THAT SUPPORTS CREATIVITY SESSIONS IN AUTOMOTIVE PRODUCT DEVELOPMENT

AbstractThe basis for developing future products in the automotive industry is finding creative and innovative solutions. Ideas can be found by means of creativity methods that support product developers throughout the creative process. Product developers are provided with a variety of different and new methods. This leads to a “method jungle” in which it is difficult for product developers to find the most suitable path. The successful use of methods in product development goes hand in hand with the acceptance and implementation of the methods. Despite the added value, only a low use is observed in the development process. The field of Creativity Support Tools also offers a wide variety of different tools that support the creativity process. Although a chasm exists between the many CSTs that are developed and what creative practitioners actually use. Therefore, previous studies iteratively developed a user-centered tool called “IDEA” that tries to provide a tool that responds to users' needs. The question arises how the developed tool IDEA performs in “real life setting” regarding its UX and usability as well as the creativity method acceptance and level of mental workload.

Effectiveness of Workplace Interventions to Improve Health and Well-Being of Health and Social Service Workers: A Narrative Review of Randomised Controlled Trials.

Health and social service workers face high levels of workload and job stressors, which can affect their health and well-being. Therefore, it is important to evaluate the effectiveness of workplace interventions that aim to improve their mental and physical health outcomes. This review summarizes the findings of randomized controlled trials (RCTs) that examined the impact of different types of workplace interventions on various health indicators among health and social service workers. The review searched the PubMed database from its inception to December 2022 and included RCTs that reported on the effectiveness of organizational-level interventions and qualitative studies that explored barriers and facilitators to participation in such interventions. A total of 108 RCTs were included in the review, covering job burnout (N = 56 RCTs), happiness or job satisfaction (N = 35), sickness absence (N = 18), psychosocial work stressors (N = 14), well-being (N = 13), work ability (N = 12), job performance or work engagement (N = 12), perceived general health (N = 9), and occupational injuries (N = 3). The review found that several workplace interventions were effective in improving work ability, well-being, perceived general health, work performance, and job satisfaction and in reducing psychosocial stressors, burnout, and sickness absence among healthcare workers. However, the effects were generally modest and short-lived. Some of the common barriers to participation in workplace interventions among healthcare workers were inadequate staff, high workload, time pressures, work constraints, lack of manager support, scheduling health programs outside work hours, and lack of motivation. This review suggests that workplace interventions have small short-term positive effects on health and well-being of healthcare workers. Workplace interventions should be implemented as routine programs with free work hours to encourage participation or integrate intervention activities into daily work routines.

The moderation of satisfaction with working conditions in the association between workload and mental health among healthcare workers collecting test samples in the post-COVID-19 era.

This study aimed to examine the associations between workload and satisfaction with working conditions and mental health (i.e., anxiety disorder, depression, and somatization) of healthcare workers collecting test samples during the local outbreaks of COVID-19, and explore satisfaction with working conditions as a moderator of these relationships. A total of 1,349 participants were obtained via an online survey in Zhengzhou, Henan Province, China. Multivariate regression was used to assess the associations between workload and satisfaction with working conditions and anxiety disorder, depression, and somatization. The simple slope analysis and Johnson-Neyman technique were used to assess the effect value and change trend of the moderator. The prevalence of anxiety disorder, depression, and somatization were 8.6, 6.9, and 19.2% of healthcare workers collecting test samples, respectively. High levels of workload were associated with an increased risk of an anxiety disorder (OR = 1.81, 95%CI = 1.17-2.78), depression (OR = 1.92, 95%CI = 1.19-3.10), and somatization (OR = 1.90, 95%CI = 1.40-2.57), while high satisfaction of working conditions was associated with a reduction in the risk of these outcomes, and ORs (95%CI) were 0.35 (0.20-0.64), 0.27 (0.13-0.56), and 0.32 (0.21-0.48), respectively. The findings also indicated that a weaker association between workload and anxiety disorder, as well as depression and somatization, has been reported in those with a high level of satisfaction with working conditions. Workload significantly increased the risk of healthcare workers suffering from psychological problems, while satisfaction with working conditions alleviated these negative effects, and effective resource support was crucial for healthcare workers.

Levels and influencing factors of mental workload among intensive care unit nurses: A systematic review and meta-analysis.

The purpose of this systematic review was to determine the levels and influencing factors of mental workload in intensive care unit nurses. Intensive care unit nurses have a high mental workload level. To our knowledge, no meta-analytic research investigating the levels of mental workload in intensive care unit nurses and related factors has yet been performed. This article is a systematic review and meta-analysis. Eleven electronic databases were searched from the database setup dates until 31 December 2022. The research team independently conducted study selection, quality assessments, data extractions and analysis of all included studies. The PRISMA guideline was used to guide reportage of the systematic review and meta-analysis. Seventeen studies were included. In these studies, the pooled mean score of mental workload was 68.07 (95%CI:64.39-71.75). Furthermore, subgroup analyses indicated that intensive care unit nurses' mental workload differed significantly by countries, sample size and publication year. The mental workload influential factors considered were demographic, work-related and psychological factors. Hospital administrators should develop interventions to reduce mental workload to enhance the mental health of intensive care unit nurses and nursing care quality. Hospital managers should pay attention to the mental health of nurses and guide them to correctly relieve occupational stress and reduce mental workload.

Pengaruh Beban Kerja, Disiplin Kerja dan Stres Kerja terhadap Kinera Karyawan pada PT Hindoli (A Cargill Company)

This study aims to determine how much influence the level of workload, work discipline, and work stress on employee performance at PT Hindoli (A Cargill Company). This study uses quantitative methods and analysis using multiple linear regression analysis. Testing this research using SPSS version 24 with a total sample of 93 respondents. The results of the first regression analysis prove that workload (X1) has no effect on employee performance, which means that H1 is rejected. The level of tasks given by the company is in accordance with the abilities of employees, and the majority of employees are men who have stronger immune systems so that the workload does not affect employee performance. The results of the second regression analysis prove that work discipline (X2) has an effect on employee performance, which means that H2 is accepted. The higher the level of work discipline, the better the employee's performance. The results of the third regression analysis prove that work stress (X3) affects employee performance, which means H3 is accepted. The stress experienced by employees is low stress that employees can still overcome and it does not become an obstacle to employee performance. Taken together, the variables of workload (X1), work discipline (X2) and work stress (X3) affect employee performance.

Generating balanced workload allocations in hospitals

As pressure on healthcare systems continues to increase, it is becoming more and more important for hospitals to properly manage the high workload levels of their staff. Ensuring a balanced workload allocation between various groups of employees in a hospital has been shown to contribute considerably towards creating sustainable working conditions. However, allocating work to different organizational units in a fair manner is not straightforward when it involves complex decision-making processes. In this paper we set out to balance the workload of heterogeneous hospital wards by optimizing the patient admission scheduling problem. Given the multi-period nature of patient admission scheduling, we introduce a new equity objective that captures both spatial (between hospital wards) and temporal (between days in the planning period) workload balancing. The resulting bi-objective problem is solved using an exact criterion space search algorithm. Our computational study employs problem instances that have been generated based on real-world data. The results demonstrate how spatially and temporally balanced workload allocations can be generated by minimizing the proposed equity objective. Moreover, we analyze sets of nondominated solutions to gain various insights into the trade-off between schedule cost and workload balance.

Intraoperative workload in elective open vascular and endovascular surgery: A study of procedural drivers

This study investigated vascular surgeon workload and its association with specific procedural drivers over different procedure types. Thirteen attending vascular surgeons (two females) were emailed a survey over a 3-month period. Data from 253 surgical procedures (118 open, 85 endovascular, 18 hybrid, and 32 venous) revealed high physical and cognitive workload among vascular surgeons. Based on the statistically significant findings and similar non-significant trends in the data (significance level of 0.01), open and hybrid vascular procedures showed higher levels of physical and cognitive workload compared to venous cases, while endovascular procedures were relatively more moderate. Additionally, the workload subscales for five subcategories of open procedures (e.g., arteriovenous access) as well as three subcategories of endovascular procedures (e.g., aortic) were compared. The granularity of the intraoperative workload drivers across various vascular procedure types and adjunct equipment could be the key to create targeted ergonomic interventions to reduce workload during vascular surgeries.

Using EEG signals to assess workload during memory retrieval in a real-world scenario

Objective. The electroencephalogram (EEG) is gaining popularity as a physiological measure for neuroergonomics in human factor studies because it is objective, less prone to bias, and capable of assessing the dynamics of cognitive states. This study investigated the associations between memory workload and EEG during participants’ typical office tasks on a single-monitor and dual-monitor arrangement. We expect a higher memory workload for the single-monitor arrangement. Approach. We designed an experiment that mimics the scenario of a subject performing some office work and examined whether the subjects experienced various levels of memory workload in two different office setups: (1) a single-monitor setup and (2) a dual-monitor setup. We used EEG band power, mutual information, and coherence as features to train machine learning models to classify high versus low memory workload states. Main results. The study results showed that these characteristics exhibited significant differences that were consistent across all participants. We also verified the robustness and consistency of these EEG signatures in a different data set collected during a Sternberg task in a prior study. Significance. The study found the EEG correlates of memory workload across individuals, demonstrating the effectiveness of using EEG analysis in conducting real-world neuroergonomic studies.

Influence of Face Masks on Physiological and Subjective Response during 130 Min of Simulated Light and Medium Physical Manual Work-An Explorative Study.

Undesirable side effects from wearing face masks during the ongoing COVID-19 pandemic continue to be discussed and pose a challenge to occupational health and safety when recommending safe application. Only few studies examined the effects of continuously wearing a face mask for more than one hour. Therefore, the influence of wearing a medical mask (MedMask) and a filtering facepiece class II respirator (FFP2) on the physiological and subjective outcomes in the course of 130 min of manual work was exploratively investigated. Physical work load and cardiorespiratory fitness levels were additionally considered as moderating factors. Twenty-four healthy subjects (12 females) from three different cardiorespiratory fitness levels each performed 130 min of simulated manual work with light and medium physical workload using either no mask, a MedMask or FFP2. Heart rate, transcutaneous oxygen and carbon dioxide partial pressure (PtcO2, PtcCO2) as well as perceived physical exertion and respiratory effort were assessed continuously at discrete time intervals. Wearing comfort of the masks were additionally rated after the working period. There was no difference in time-dependent changes of physiological outcomes when using either a MedMask or a FFP2 compared to not wearing a mask. A stronger increase over time in perceived respiratory effort occurred when the face masks were worn, being more prominent for FFP2. Physical workload level and cardiorespiratory fitness level were no moderating factors and higher wearing comfort was rated for the MedMask. Our results suggest that using face masks during light and medium physical manual work does not induce detrimental side effects. Prolonged wearing episodes appeared to increase respiratory effort, but without affecting human physiology in a clinically relevant way.

Does workplace telepressure get under the skin? Protocol for an ambulatory assessment study on wellbeing and health-related physiological, experiential, and behavioral concomitants of workplace telepressure

BackgroundThe daily working life of many employees requires the use of modern information and communication technology (ICT) devices such as computers, tablets, and smartphones. The double-edged nature of digital work environments has been increasingly highlighted. Benefits such as increased flexibility come at a personal cost. One of the potential downsides is workplace telepressure, i.e., the experience of urge and preoccupation to quickly reply to work-related messages and demands using ICT. There is initial − mainly survey-based−evidence that workplace telepressure may have negative effects on a variety of wellbeing and health outcomes.Aims and hypothesesAdopting the Effort-Recovery Model and the concept of allostatic load as theoretical frameworks, the present study aims to investigate the hypothesis that workplace telepressure is significantly associated with increased “wear and tear”, in the form of more psychosomatic complaints, worse sleep quality (self-reported and actigraphy-based), worse mood, and biological alterations (lower cardiac vagal tone, lower anabolic balance defined as the ratio of salivary dehydroepiandrosterone to salivary cortisol, and higher salivary alpha-amylase). Additionally, the study aims to investigate the hypothesis that connection to work defined as work-related workload and work-related perseverative cognition plays a significant role in the mediation of these relationships.MethodsTo test our hypotheses, we will conduct an ambulatory assessment study with a convenience sample of 120 healthy workers regularly using ICTs for job communication. For one week, participants will be asked to complete electronic diaries assessing their level of workplace telepressure, psychosomatic complaints, sleep quality, mood, work-related workload, and work-related perseverative cognition. They will also continuously wear the Bittium Faros 180L ECG monitor, the wrist-worn actigraph MotionWatch 8, and perform saliva sampling five times per day.DiscussionThis study will be the most comprehensive ambulatory investigation of workplace telepressure and its psychophysiological concomitants to date and constitutes an important step towards understanding how high levels of workplace telepressure may lead in the long term to secondary alterations (e.g., hypertension, chronic inflammation) and disease (e.g., heart disease). The findings of this study are also anticipated to contribute to guiding the development and implementation of interventions, programs, and policies relevant to employees’ digital wellbeing.

Robust PPG-Based Mental Workload Assessment System Using Wearable Devices.

Heart rate variability (HRV) has been used in assessing mental workload (MW) level. Compared with ECG, photoplethysmogram (PPG) provides convenient in assessing MW with wearable devices, which is more suitable for daily usage. However, PPG collected by smartwatches are prone to suffer from artifacts. Those signal corruptions cause invalid Inter-beat Intervals (IBI), making it challenging to evaluate the HRV feature. Hence, the PPG-based MW assessment system is difficult to obtain a sustainable and reliable assessment of MW. In this paper, we propose a pre- and post- processing technique, called outlier removal and uncertainty estimation, respectively, to reduce the negative influences of invalid IBIs. The proposed method helps to acquire accurate HRV features and evaluate the reliability of incoming IBIs, rejecting possibly misclassified data. We verified our approach in two open datasets, which are CLAS and MAUS. Experiment results show proposed method achieved higher accuracy (66.7% v.s. 74.2%) and lower variance (11.3% v.s. 10.8%) among users, which has comparable performance to an ECG-based MW system.