Employee acceptability of wearable mental workload monitoring in industry 4.0 : a pilot study on motivational and contextual framing

As Industry 4.0 will greatly challenge employee mental workload (MWL), research on objective wearable MWL-monitoring is in high demand. However, numerous research lines validating such technology might become redundant when employees eventually object to its implementation. In a pilot study, we manipulated two ways in which employees might perceive MWL-monitoring initiatives. We found that framing the technology in terms of serving intrinsic goals (e.g., improving health) together with an autonomy-supportive context (e.g., allowing discussion) yields higher user acceptability when compared to framing in terms of extrinsic goals (e.g., increasing productivity) together with a controlling context (e.g., mandating use). User acceptability still panned out neutral in case of the former, however - feeding into our own and suggested future work

Understanding mental workload : from a clarifying concept analysis toward an implementable framework

The growing need for mental workload (MWL) optimization on the shop floor yields an impressive increase in theoretical and applied references to the concept of mental workload (Young et al. 2014). However, do we really understand and agree upon what mental workload exactly is? Does it include emotional load? Can we rely upon an explanatory framework? The present account first runs a critical concept analysis on mental workload, based on the Walker and Avant (2011) method. Results show that existing definitions and theoretical accounts arbitrarily include and exclude defining variables and describe these variables on various levels of abstraction, misuse pivotal terms such as mediation and moderation, and do not theoretically explicitate the role of yet repeatedly operationalized emotional load variables such as frustration. We therefore clarify the concept by disentangling MWL into its antecedents, defining attributes and consequences. Next, we derive a clear-cut conceptual definition and present a generic explanatory framework - the latter extended with insights from Cognitive Load Theory (Sweller 1988; 1994). We conclude with a set of suggestions for future research and practice. Next to contributing to the theoretical clarification of this hallmark concept, the concept analysis and derived explanatory framework, as proposed, can foster solid research practices and support practitioners in contextualizing MWL-assessment and in effectively optimizing MWL

Lignin engineering in field-grown poplar trees affects the endosphere bacterial microbiome

Cinnamoyl-CoA reductase (CCR), an enzyme central to the lignin bio-synthetic pathway, represents a promising biotechnological target to reduce lignin levels and to improve the commercial viability of lignocellulosic biomass. However, silencing of the CCR gene results in considerable flux changes of the general and monolignol-specific lignin pathways, ultimately leading to the accumulation of various extractable phenolic compounds in the xylem. Here, we evaluated host genotype-dependent effects of field-grown, CCR-down-regulated poplar trees (Populus tremula x Populus alba) on the bacterial rhizosphere microbiome and the endosphere microbiome, namely the microbiota present in roots, stems, and leaves. Plant-associated bacteria were isolated from all plant compartments by selective isolation and enrichment techniques with specific phenolic carbon sources (such as ferulic acid) that are up-regulated in CCR-deficient poplar trees. The bacterial microbiomes present in the endosphere were highly responsive to the CCR-deficient poplar genotype with remarkably different metabolic capacities and associated community structures compared with the WT trees. In contrast, the rhizosphere microbiome of CCR-deficient and WT poplar trees featured highly overlapping bacterial community structures and metabolic capacities. We demonstrate the host genotype modulation of the plant microbiome by minute genetic variations in the plant genome. Hence, these interactions need to be taken into consideration to understand the full consequences of plant metabolic pathway engineering and its relation with the environment and the intended genetic improvement

Design for assembly meaning : a framework for designers to design products that support operator cognition during the assembly process

Designing assembly instructions is mostly considered to be a non-designer task. Hence, in many companies, it is performed by production planners or instructional designers. However, analysing product components and looking for clues on how these components can be fitted together into a subassembly or final product is a fundamental part of assembly. Product designers play an important role in the way these components are perceived by the operator. This paper discusses the need and importance of a new approach to product design focused on how the assembly design can promote meaning to the operator, supporting operator cognition. The aim of this approach is to guide assembly operators more intuitively through their increasingly complex tasks. Doing so will allow them to avoid some of the major drawbacks that are present when using procedural instructions. Hence, this approach has the potential to decrease cognitive load and frustration, and increase mental wellbeing, work motivation and efficiency. As a first step towards this new approach, a conceptual framework is constructed, and insights are formulated after reviewing various design theories and concepts of design for meaning on their potential in a context of manual assembly

Impact of user involvement on design students’ motivation and self-confidence

Involvement of users in the design process is generally viewed favourably, both within academia and industry. Their involvement can be seen as a strategy for designers to clarify their design task and reduce uncertainties in the design process. Simultaneously, there is a lack of understanding about the impact that user involvement has on students and how they experience doing so. This paper reports on a study where students were asked to self-report their motivation and self-confidence throughout a design exercise, stretching 11 days, with surveys repeating daily. Additionally, students were asked to indicate which-if any-strategies of user involvement they used every day. We find that students self-reported motivation did not change statistically significantly, while self-confidence did change. However, in neither case did student's involvement of end-users impact how motivated or self-confident they were. We discuss our results in relation to existing research on method use in general and user involvement in particular and conclude with some suggestions for future work

Improving productivity and worker conditions in assembly : part 2 : rapid deployment of learnable robot skills

Collaborative robots (cobots) have a strong potential to improve both productivity as well as the working conditions of assembly operators by assisting in their tasks and by decreasing their physical and cognitive stress. The use of cobots in factories however introduces multiple challenges: how should the overall assembly architecture look like? How to allocate specific (sub)tasks to the operator or the cobot? How to program and deploy the cobot? How to make changes to the robot program? In this paper dilogy, we briefly highlight our recent contributions to this field. In part I we presented our collaborative architecture for human-robot assembly tasks and discussed the working principles of our task allocation framework, based upon agent capabilities and ergonomic measurements. In this second part we focus on our programming by demonstration approach targeted at expediting the deployment of learnable robot skills

Mobile pupillometry in manual assembly : a pilot study exploring the wearability and external validity of a renowned mental workload lab measure

Human operators in the upcoming Industry 4.0 workplace will face accelerating job demands such as elevated cognitive complexity. Unobtrusive objective measures of mental workload (MWL) are therefore in high demand as indicated by both theory and practice. This pilot study explored the wearability and external validity of pupillometry, a MWL measure robustly validated in laboratory settings and now deployable in work settings demanding operator mobility. In an ecologically valid work environment, 21 participants performed two manual assemblies - one of low and one of high complexity - while wearing eye-tracking glasses for pupil size measurement. Results revealed that the device was perceived as fairly wearable in terms of physical and mental comfort. In terms of validity, no significant differences in mean pupil size were found between the assemblies even though subjective mental workload differed significantly. Exploratory analyses on the pupil size when attending to the assembly instructions only, were inconclusive. The present work suggests that current lab-based procedures might not be adequate yet for in-the-field mobile pupillometry. From a broader perspective, these findings also invite a more nuanced view on the current validity of lab-validated physiological MWL-measures when applied in real-life settings. We therefore conclude with some key insights for future development of mobile pupillometry

Mental workload monitoring in the manufacturing industry : conceptualisation, operationalisation and implementation

The industrial workplace is currently transforming into a knowledge driven and highly digitalized work environment yielding small batches of highly complex products. Coined 'Industry 4.0', this workplace is expected to put higher demands on the operator’s mental processing. In order to support the optimization of operator mental workload on the future shop floor, this interdisciplinary doctorate builds on seminal research in psychology and industrial design to help provide practitioners with a robust mental workload measure. In the conceptualization stage, a clear-cut conceptual definition of mental workload and a generic and implementable explanatory framework is presented. During the operationalization stage, first, the external validity of mobile pupillometry is explored in an assembly experiment. Secondly, a novel mental workload measure is designed and validated, based on observable assembly behavior such as 'freezing' of the hands and the amount of assembly part rotations made. The implementation stage, finally, gauges the wearability and applicability of these measures, to conclude with two studies on the employee acceptability of mental workload monitoring. Envisioning the technology’s future development the dissertation suggests that research should invest in long-term within-subjects triangulated field measurement, rooted in common theoretical and methodological grounds and supported by dynamic machine learning

Framework to redesign products with focus on design for assembly meaning : a PBL case study

In many companies and especially in companies producing small series of products, manual assembly is highly needed for its flexibility. Complexity of manual assembly tasks is increasing in these companies and operators need to be supported. A framework was developed to facilitate designers to design for assembly meaning, a product design approach that aims to improve the intuitiveness of the assembly process and tries to lower the need for procedural instructions. In this paper, a project based learning (PBL) case study was used to assess the framework. In this study, twenty-eight students redesigned six light fixtured based on the analysis of the assembly process and in close cooperation with the company. The results of a survey taken from the students showed that the framework was valued by many students within a PBL setting. Moreover the solutions designed by the students to foster a more intuitive assembly were valuable, mostly feasible and showing a variety of solutions. The added value of offering a framework to design for meaning in assembly and to implement this in a PBL setting with access to a company, operators, products and prototyping facilities was also illustrated. The framework, method and tools are all discussed within the context of project based learning