An Architecture for the Integration of Human Workers into an Industry 4.0 Manufacturing Environment.

Thesis (PhD)--Stellenbosch University, 2021.ENGLISH SUMMARY: With the rise of Industry 4.0 and the development in technologies that contribute to this revolution in manufacturing, research has focused mainly on the machines and automated digital systems contributing to the manufacturing environment. Humans are still critical to manufacturing; offering unmatched ingenuity, robustness, and flexibility despite their apparent disadvantages in strength or precision. Many successful manufacturing firms still include humans in their manufacturing processes for these reasons, and it is critical that the integration of humans in an I4.0 manufacturing environment is given research attention. This dissertation first explores the requirements for the integration of human workers into an I4.0 environment. It was determined that the largest problem with human integration exists with data related to the human being digitised, managed, and communicated with other entities in processes that are identified as Administrative Logistics. It is identified that an administration shell similar to the RAMI4.0 administration shell concept is required to manage these Administrative Logistics on behalf of the human, and that a holonic systems approach is beneficial. The dissertation then proposes the concept of a Human Resource Holon Administration shell (HRH-AS). An architecture to implement such an administration shell is then developed, here named the BASE architecture. This administration shell facilitates the interfacing, data processing, and connectivity to other I4.0 components on behalf of the human, to aid in their integration to the digital factory environment around them. The BASE architecture addresses three identified responsibilities of such an administration shell, namely interfacing, digital data management, and delegation to other I4.0 components. BASE stands for Biography, Attributes, Schedule, and Execution, and is a time-based separation of concerns for key augmentations provided to the human worker. The BASE architecture separates value-adding and decision-making plugin components, which are specific to an application, from the core components, which are generic to any application. The BASE architecture led to the development of the 3SAL activity structure to facilitate the communication and management of industrial activities in a digital environment. With the help of an industry partner, two case studies were developed to evaluate an implementation of the BASE architecture. The company is an aerospace composites manufacturer and was chosen for the labour-intensive requirements of the composites industry. The case studies aimed to evaluate the architecture against the three identified administration shell responsibilities and determine if the human workers are elevated to resource holon status. The first case study aimed to show how BASE facilitates interfacing with humans in an I4.0 environment and also acted as a technology demonstrator for the second case study. The second case study evaluated the effect BASE had on the Administrative Logistics involved in the business processes workers were involved in. Together these case studies fully evaluate BASE’s ability to facilitate the integration of humans into an I4.0 manufacturing environment through identified responsibilities of the administration shell. The evaluation found that the BASE HRH-AS improves the effectiveness of Administrative Logistics of business processes the human workers were involved with, as well as opened new opportunities for decision making on the shop floor previously not possible. Value-adding, by means of the plug-in components of a BASE administration shell, has also been proven by the ability to do automated schedule management, automatic calculation of standard work and improved traceability using the 3SAL activity structure.AFRIKAANS OPSOMMING: Met die opkoms van Industrie 4.0 (I4.0) en die ontwikkeling in tegnologieë wat bydra tot hierdie revolusie in vervaardiging, het navorsing grotendeels gefokus op die masjiene en digitale stelsels wat tot die vervaardigingsomgewing bydra. Menslike werkers is steeds van kritieke belang vir vervaardiging, en bied ongeëwenaarde vindingrykheid, robuustheid en buigsaamheid, ondanks hul oënskynlike nadele in sterkte of noukeurigheid. Baie suksesvolle vervaardigingsondernemings sluit nogsteeds mense in hul vervaardigingsprosesse in om hierdie redes. Dit is dus noodsaaklik dat die integrasie van mense met 'n I4.0 vervaardigingsomgewing navorsingsaandag geniet. Hierdie verhandeling ondersoek eerstens die vereistes vir die integrasie van menslike werkers in 'n I4.0 omgewing. Daar word eerstens geïdentifiseer dat die grootste probleem met die integrasie van mense bestaan uit oneffektiewe prosesse wat data en informasie tussen mense en ander komponente in die vervaardigingsprosesse komminikeer, stoor en bestuur. Hierdie prosesse word na verwys as Administratiewe Logistieke. Daar word ook geïdentifiseer dat 'n administrasie-dop soortgelyk aan die RAMI4.0 administrasie-dop konsep benodig word om Administratiewe Logistieke te bestuur namens die mens, en dat 'n holoniese stelselbenadering voordelig is. Die verhandeling stel dan die konsep van 'n Human Resource Holon Administration Shell (HRH-AS) voor. Daarna word 'n argitektuur ontwikkel om so 'n administrasie-dop te implementeer, hier genoem die BASE argitektuur. Hierdie administrasie-dop vergemaklik die inskakeling, dataverwerking en konnektiwiteit met ander I4.0 komponente namens die mens. Die integrasie van die mens in die digitale fabrieksomgewing is dus bevoordeel. Die BASE argitektuur spreek drie geïdentifiseerde verantwoordelikhede van so 'n administrasie-dop aan, naamlik: koppelling met die mens, digitale databestuur, en delegering na ander I4.0 komponente namens die mens. BASE staan vir Biography, Attributes, Schedule en Execution, en is 'n tydgebaseerde skeiding van belange vir aanvullings wat aan die menslike werker verskaf word. Die BASE argitektuur skei waardetoevoeging- en besluitneming-inpropkomponente, wat spesifiek vir 'n toepassing is, van die kernkomponente, wat generies is vir enige toepassing. Die BASE argitektuur het gelei tot die ontwikkeling van die 3SAL aktiwiteitstruktuur om die kommunikasie en bestuur van industriële aktiwiteite in 'n digitale omgewing te vergemaklik. Met die hulp van 'n bedryfsvennoot is twee gevallestudies ontwikkel om 'n implementering van die BASE argitektuur te evalueer. Die maatskappy is 'n lugvaart saamgestelde-mater komponent vervaardiger en is gekies vir die arbeidsintensiewe vereistes van die saamgestelde-mater bedryf. Die gevallestudies was daarop gemik om die argitektuur teen die drie geïdentifiseerde verantwoordelikhede van die administrasiedop te evalueer en te bepaal of die menslike werkers verhoog word tot holon status. Die eerste gevallestudie se doel was om te wys hoe BASE n koppelvlak tussen mense en digitale stelsels toelaat. Die eerste gevallestudie was ook 'n demonstrasie dat 'n toepassing in die bedryfsvenoot se fabriek toegepas kon word vir die tweede gevallestudie. Die tweede gevallestudie het die effek geëvalueer wat BASE het op die Administratiewe Logistiek betrokke by die besigheidsprosesse waarby werkers betrokke was. Saam evalueer hierdie gevallestudies BASE se vermoë om die integrasie van mense in 'n I4.0 vervaardigingsomgewing te fasiliteer deur geïdentifiseerde verantwoordelikhede van die administrasiedop. Die evaluering het bevind dat die BASE HRH-AS die doeltreffendheid van Administratiewe Logistiek van besigheidsprosesse wat menslike werkers benut, asook nuwe geleenthede vir besluitneming op die winkelvloer, verbeter tot n mate wat voorheen nie moontlik was nie. Waarde-toevoeging, deur middel van die inpropkomponente van 'n BASE administrasie dop, is ook bewys deur die vermoë om outomatiese skedule-bestuur, outomatiese berekening van standaardwerk en verbeterde naspeurbaarheid met behulp van die 3SAL-aktiwiteitsstruktuur te doen.Doctora

Coexistence of single-mode and multi-longitudinal mode emission in the ring laser model

A homogeneously broadened unidirectonal ring laser can emit in several longitudinal modes for large enough pump and cavity length because of Rabi splitting induced gain. This is the so called Risken-Nummedal-Graham-Haken (RNGH) instability. We investigate numerically the properties of the multi-mode solution. We show that this solution can coexist with the single-mode one, and its stability domain can extend to pump values smaller than the critical pump of the RNGH instability. Morevoer, we show that the multi-mode solution for large pump values is affected by two different instabilities: a pitchfork bifurcation, which preserves phase-locking, and a Hopf bifurcation, which destroys it.Comment: 14 pages, 7 figure

Interaction of Stress, Lead Burden, and Age on Cognition in Older Men: The VA Normative Aging Study

BACKGROUND. Low-level exposure to lead and to chronic stress may independently influence cognition. However, the modifying potential of psychosocial stress on the neurotoxicity of lead and their combined relationship to aging-associated decline have not been fully examined. OBJECTIVES. We examined the cross-sectional interaction between stress and lead exposure on Mini-Mental State Examination (MMSE) scores among 811 participants in the Normative Aging Study, a cohort of older U.S. men. METHODS. We used two self-reported measures of stress appraisal-a self-report of stress related to their most severe problem and the Perceived Stress Scale (PSS). Indices of lead exposure were blood lead and bone (tibia and patella) lead. RESULTS. Participants with higher self-reported stress had lower MMSE scores, which were adjusted for age, education, computer experience, English as a first language, smoking, and alcohol intake. In multivariable-adjusted tests for interaction, those with higher PSS scores had a 0.57-point lower (95% confidence interval, -0.90 to 0.24) MMSE score for a 2-fold increase in blood lead than did those with lower PSS scores. In addition, the combination of high PSS scores and high blood lead categories on one or both was associated with a 0.05-0.08 reduction on the MMSE for each year of age compared with those with low PSS score and blood lead level (p < 0.05). CONCLUSIONS. Psychological stress had an independent inverse association with cognition and also modified the relationship between lead exposure and cognitive performance among older men. Furthermore, high stress and lead together modified the association between age and cognition.National Institutes of Health (R01ES07821, R01HL080674, R01HL080674-02S1, R01ES013744, ES05257-06A1, P20MD000501, P42ES05947, ES03918-02); National Center for Research Resources General Clinical Research Center (M01RR02635); Leaves of Grass Foundation; United States Department of Veterans Affair

The effects of laterality on obstacle crossing performance in unilateral trans-tibial amputees

yesBackground Unilateral trans-tibial amputees have bilaterally reduced toe clearance, and an increased risk of foot contact, while crossing obstacles compared to the able-bodied. While the able-bodied tend to lead with a ‘preferred’ limb it is equivocal whether amputees prefer to lead with the intact or prosthetic limb. This study determined the effects of laterality, compared to side of amputation, on amputees' obstacle crossing performance. To help understand why laterality could affect performance we also assessed knee proprioception for both limbs. Methods Foot placement and toe clearance parameters were recorded while nine amputees crossed obstacles of varying heights leading with both their intact and prosthetic limbs. Joint-position sense was also assessed. Participants self-reported which limb was their preferred (dominant) limb. Findings There were no significant differences in foot placements or toe clearance variability across lead-limb conditions. There were no significant differences in toe clearance between intact and prosthetic lead-limbs (p = 0.28) but toe clearance was significantly higher when amputees led with their preferred compared to non-preferred limb (p = 0.025). There was no difference in joint-position sense between the intact and residual knees (p = 0.34) but joint-position sense tended to be more accurate for the preferred, compared to non-preferred limb (p = 0.08). Interpretation Findings suggest that, despite the mechanical constraints imposed by use of a prosthesis, laterality may be as important in lower-limb amputees as it is in the able bodied. This suggests that amputees should be encouraged to cross obstacles leading with their preferred limb.Engineering and Physical Sciences Research Counci

Analysis of the Brinkman-Forchheimer equations with slip boundary conditions

In this work, we study the Brinkman-Forchheimer equations driven under slip boundary conditions of friction type. We prove the existence and uniqueness of weak solutions by means of regularization combined with the Faedo-Galerkin approach. Next we discuss the continuity of the solution with respect to Brinkman's and Forchheimer's coefficients. Finally, we show that the weak solution of the corresponding stationary problem is stable

Solar X-ray Flare Hazards on the Surface of Mars

Putative organisms on the Martian surface would be exposed to potentially high doses of ionizing radiation during strong solar X-ray flares. We extrapolate the observed flare frequency-energy release scaling relation to releases much larger than seen so far for the sun, an assumption supported by observations of flares on other solar- and subsolar-mass main sequence stars. We calculate the surficial reprocessed X-ray spectra using a Monte Carlo code we have developed. Biological doses from indirect genome damage are calculated for each parameterized flare spectrum by integration over the X-ray opacity of water. We estimate the mean waiting time for solar flares producing a given biological dose of ionizing radiation on Mars and compare with lethal dose data for a wide range of terrestrial organisms. These timescales range from decades for significant human health risk to 0.5 Myr for D. radiodurans lethality. Such doses require total flare energies of 10^33--10^38 erg, the lower range of which has been observed for other stars. Flares are intermittent bursts, so acute lethality will only occur on the sunward hemisphere during a sufficiently energetic flare, unlike low-dose-rate, extended damage by cosmic rays. We estimate the soil and CO_2 ice columns required to provide 1/e shielding as 4--9 g cm^-2, depending on flare mean energy and atmospheric column density. Topographic altitude variations give a factor of two variation in dose for a given flare. Life in ice layers that may exist ~ 100 g cm^-2 below the surface would be well protected.Comment: To be published in Planetary and Space Science; 33 pages, 3 figure

Determinants of Bone and Blood Lead Levels among Minorities Living in the Boston Area

We measured blood and bone lead levels among minority individuals who live in some of Boston’s neighborhoods with high minority representation. Compared with samples of predominantly white subjects we had studied before, the 84 volunteers in this study (33:67 male:female ratio; 31–72 years of age) had similar educational, occupational, and smoking profiles and mean blood, tibia, and patella lead levels (3 μg/dL, 11.9 μg/g, and 14.2 μg/g, respectively) that were also similar. The slopes of the univariate regressions of blood, tibia, and patella lead versus age were 0.10 μg/dL/year (p < 0.001), 0.45 μg/g/year (p < 0.001), and 0.73 μg/g/year (p < 0.001), respectively. Analyses of smoothing curves and regression lines for tibia and patella lead suggested an inflection point at 55 years of age, with slopes for subjects ≥ 55 years of age that were not only steeper than those of younger subjects but also substantially steeper than those observed for individuals > 55 years of age in studies of predominantly white participants. This apparent racial disparity at older ages may be related to differences in historic occupational and/or environmental exposures, or possibly the lower rates of bone turnover that are known to occur in postmenopausal black women. The higher levels of lead accumulation seen in this age group are of concern because such levels have been shown in other studies to predict elevated risks of chronic disease such as hypertension and cognitive dysfunction. Additional research on bone lead levels in minorities and their socioeconomic and racial determinants is needed

Autistic symptomatology and language ability in Autism Spectrum Disorder and Specific Language Impairment

Background: Autism spectrum disorders (ASD) and specific language impairment (SLI) are common developmental disorders characterised by deficits in language and communication. The nature of the relationship between them continues to be a matter of debate. This study investigates whether the co-occurrence of ASD and language impairment is associated with differences in severity or pattern of autistic symptomatology or language profile. Methods: Participants (N = 97) were drawn from a total population cohort of 56,946 screened as part of study to ascertain the prevalence of ASD, aged 9 to 14 years. All children received an ICD-10 clinical diagnosis of ASD or No ASD. Children with nonverbal IQ 80 were divided into those with a language impairment (language score of 77 or less) and those without, creating three groups: children with ASD and a language impairment (ALI; N = 41), those with ASD and but no language impairment (ANL; N = 31) and those with language impairment but no ASD (SLI; N = 25). Results: Children with ALI did not show more current autistic symptoms than those with ANL. Children with SLI were well below the threshold for ASD. Their social adaptation was higher than the ASD groups, but still nearly 2 SD below average. In ALI the combination of ASD and language impairment was associated with weaker functional communication and more severe receptive language difficulties than those found in SLI. Receptive and expressive language were equally impaired in ALI, whereas in SLI receptive language was stronger than expressive. Conclusions: Co-occurrence of ASD and language impairment is not associated with increased current autistic symptomatology but appears to be associated with greater impairment in receptive language and functional communication

Spatiotemporal oscillations of Notch1, Dll1 and NICD are coordinated across the mouse PSM

During somitogenesis, epithelial somites form from the pre-somitic mesoderm (PSM) in a periodic manner. This periodicity is regulated by a molecular oscillator, known as the ‘segmentation clock’, that is characterised by an oscillatory pattern of gene expression that sweeps the PSM in a caudal-rostral direction. Key components of the segmentation clock are intracellular components of the Notch, Wnt and FGF pathways, and it is widely accepted that intracellular negative-feedback loops regulate oscillatory gene expression. However, an open question in the field is how intracellular oscillations are coordinated, in the form of spatiotemporal waves of expression, across the PSM. In this study, we provide a potential mechanism for this process. We show at the mRNA level that the Notch1 receptor and Delta-like 1 (Dll1) ligand vary dynamically across the PSM of both chick and mouse. Remarkably, we also demonstrate similar dynamics at the protein level; hence, the pathway components that mediate intercellular coupling themselves exhibit oscillatory dynamics. Moreover, we quantify the dynamic expression patterns of Dll1 and Notch1, and show they are highly correlated with the expression patterns of two known clock components [Lfng mRNA and the activated form of the Notch receptor (cleaved Notch intracellular domain, NICD)]. Lastly, we show that Notch1 is a target of Notch signalling, whereas Dll1 is Wnt regulated. Regulation of Dll1 and Notch1 expression thus links the activity of Wnt and Notch, the two main signalling pathways driving the clock