Development and validation of safety climate scales for mobile remote workers using utility/electrical workers as exemplar

Purpose

The objective of this study was to develop and test the reliability and validity of a new scale designed for measuring safety climate among mobile remote workers, using utility/electrical workers as exemplar. The new scale employs perceived safety priority as the metric of safety climate and a multi-level framework, separating the measurement of organization- and group-level safety climate items into two sub-scales. The question of the emergence of shared perceptions among remote workers was also examined.

Method

For the initial survey development, several items were adopted from a generic safety climate scale and new industry-specific items were generated based on an extensive literature review, expert judgment, 15-day field observations, and 38 in-depth individual interviews with subject matter experts (i.e., utility industry electrical workers, trainers and supervisors of electrical workers). The items were revised after 45 cognitive interviews and a pre-test with 139 additional utility/electrical workers. The revised scale was subsequently implemented with a total of 2421 workers at two large US electric utility companies (1560 participants for the pilot company and 861 for the second company). Both exploratory (EFA) and confirmatory factor analyses (CFA) were adopted to finalize the items and to ensure construct validity. Reliability of the scale was tested based on Cronbach's α. Homogeneity tests examined whether utility/electrical workers’ safety climate perceptions were shared within the same supervisor group. This was followed by an analysis of the criterion-related validity, which linked the safety climate scores to self-reports of safety behavior and injury outcomes (i.e., recordable incidents, missing days due to work-related injuries, vehicle accidents, and near misses).

Results

Six dimensions (Safety pro-activity, General training, Trucks and equipment, Field orientation, Financial Investment, and Schedule flexibility) with 29 items were extracted from the EFA to measure the organization-level safety climate. Three dimensions (Supervisory care, Participation encouragement, and Safety straight talk) with 19 items were extracted to measure the group-level safety climate. Acceptable ranges of internal consistency statistics for the sub-scales were observed. Whether or not to aggregate these multi-dimensions of safety climate into a single higher-order construct (overall safety climate) was discussed. CFAs confirmed the construct validity of the developed safety climate scale for utility/electrical workers. Homogeneity tests showed that utility/electrical workers’ safety climate perceptions were shared within the same supervisor group. Both the organization- and group-level safety climate scores showed a statistically significant relationship with workers’ self-reported safety behaviors and injury outcomes.

Implications

A valid and reliable instrument to measure the essential elements of safety climate for utility/electrical workers in the remote working situation has been introduced. The scale can provide an in-depth understanding of safety climate based on its key dimensions and show where improvements can be made at both group and organization levels. As such, it may also offer a valuable starting point for future safety interventions.     

Learning equilibrium as a generalization of learning to optimize

We argue that learning equilibrium is an appropriate generalization to multi-agent systems of the concept of learning to optimize in single-agent setting. We further define and discuss the concept of weak learning equilibrium.     

Monte Carlo modelling of wet-chemical lithography with masks

We propose Monte Carlo simulation of the etching process in two dimensions for the manufacture of microchannels and microcavities on a solid substrate. The method combines the effect of two different regimes based on diffusion-limited disaggregation and reaction-limited erosion, respectively. Besides, the role of the selectivity in site extraction is taken into account to foresee the effects of the temperature of the eroding bath. This technique proves to be a valid alternative to more complex analytical methods to describe surface decay processes in the presence of overhangs. The relevant geometries of the etched surfaces are analyzed, and other statistical properties of the cavities are discussed and compared to the ones predicted by continuum models.     

Metacognition in Chemistry Education: A Literature Review

Metacognition, or ′thinking about thinking′, can improve scientific literacy and practices. It involves knowledge of cognition, i. e., being cognisant of one‘s knowledge, and regulation of cognition, i. e., consciously controlling the process of knowledge acquisition. A self‐regulated learner can assimilate new knowledge, conduct inquiry, solve problems and plan ahead his or her learning. While studies have been conducted on metacognition in chemistry education, none have included detailed assignments covering a range of metacognitive strategies. Our review of studies on metacognition in chemistry secondary and higher education also includes also several exemplary assignments on the energy topic for facilitating and assessing metacognition in high school classrooms. We use metacognitive prompts and the construct of chemistry understanding levels, macroscopic, microscopic, symbol, and process, as an approach for metacognitive intervention. Finally, we provide recommendations for educators and a rubric for researchers.     

Homogeneous and heterogeneous polymorphic transformations in alkaline earth feldspars

The displacive transformations in quartz, hexacelsian and the strontium equivalent of the latter, are homogeneous incipient transformations. These transformations are carried out mostly as a second (or higher) order reaction, and are finally completed abruptly as a first-order reaction which results from a sudden release of strain accumulated due to bond stretching. In such transformations the first-order mode of reaction seems to be eliminated to various extents by the introduction of impurities as solid solution to the structure. Such impurities promote heterogeneous transformations. The extent of sluggishness of displacive transformations and of stability relationship in alkaline earth feldspars is correlated with the various ionic sizes of barium, strontium and calcium. Displacive and diffusive transformations in alkali feldspars are also homogeneous incipient transformations, but due to the high mobility of the alkali ions, building up of strain is prevented and no abrupt change in symmetry occurs at the transformation. The hexacelsian ⇌ celsian and monotropic transformations in SrAl₂Si₂O₈ and CaAl₂Si₂O₈ are heterogeneous incipient reconstructive transformations. Differences in melting temperatures reported in the past for BaAl₂Si₂O₈ may probably be correlated with the grain size, crystalline modification and extent of Al/Si order in the sample investigated.     

A Generic Integrated Line Detection Algorithm and Its Object–Process Specification

A generic integrated line detection algorithm (GILDA) is presented and demonstrated. GILDA is based on the generic graphics recognition approach, which abstracts the graphics recognition as a stepwise recovery of the multiple components of the graphic objects and is specified by the object–process methodology. We define 12 classes of lines which appear in engineering drawings and use them to construct a class inheritance hierarchy. The hierarchy highly abstracts the line features that are relevant to the line detection process. Based on the “Hypothesis and Test” paradigm, lines are detected by a stepwise extension to both ends of a selected first key component. In each extension cycle, one new component which best meets the current line's shape and style constraints is appended to the line. Different line classes are detected by controlling the line attribute values. As we show in the experiments, the algorithm demonstrates high performance on clear synthetic drawings as well as on noisy, complex, real-world drawings.     

A generalization of analytic deduction via labelled deductive systems. Part I: Basic substructural logics

In this series of papers we set out to generalize the notion of classical analytic deduction (i.e., deduction via elimination rules) by combining the methodology of labelled deductive systems (LDS) with the classical systemKE. LDS is a unifying framework for the study of logics and of their interactions. In the LDS approach the basic units of logical derivation are not just formulae butlabelled formulae, where the labels belong to a given labelling algebra. The derivation rules act on the labels as well as on the formulae, according to certain fixed rules of propagation. By virtue of the extra power of the labelling algebras, standard (classical or intuitionistic) proof systems can be extended to cover a much wider territory without modifying their structure. The systemKE is a new tree method for classical analytic deduction based on analytic cut.KE is a refutation system, like analytic tableaux and resolution, but it is essentially more efficient than tableaux and, unlike resolution, does not require any reduction to normal form.We start our investigation with the family of substructural logics. These are logical systems (such as Lambek's calculus, Anderson and Belnap's relevance logic, and Girard's linear logic) which arise from disallowing some or all of the usual structural properties of the notion of logical consequence. This extension of traditional logic yields a subtle analysis of the logical operators which is more in tune with the needs of applications. In this paper we generalize the classicalKE system via the LDS methodology to provide a uniform refutation system for the family of substructural logics.The main features of this generalized method are the following: (a) each logic in the family is associated with a labelling algebra; (b) the tree-expansion rules (for labelled formulae) are the same for all the logics in the family; (c) the difference between one logic and the other is captured by the conditions under which a branch is declared closed; (d) such conditions depend only on the labelling algebra associated with each logic; and (e) classical and intuitionistic negations are characterized uniformly, by means of the same tree-expansion rules, and their difference is reduced to a difference in the labelling algebra used in closing a branch. In this first part we lay the theoretical foundations of our method. In the second part we shall continue our investigation of substructural logics and discuss the algorithmic aspects of our approach.     

A graph grammar-based formal validation of object-process diagrams

Two basic requirements from a system’s conceptual model are correctness and comprehensibility. Most modeling methodologies satisfy only one of these apparently contradicting requirements, usually comprehensibility, leaving aside problems of correctness and ambiguousness that are associated with expressiveness. Some formal modeling languages do exist, but in these languages a complete model of a complex system is fairly complicated to understand. Object-process methodology (OPM) is a holistic systems modeling methodology that combines the two major aspects of a system—structure and behavior—in one model, providing mechanisms to manage the complexity of the model using refinement-abstraction operations, which divide a complex system into many interconnected diagrams. Although the basic syntax and semantics of an OPM model are defined, they are incomplete and leave room for incorrect or ambiguous models. This work advances the formal definition of OPM by providing a graph grammar for creating and checking OPM diagrams. The grammar provides a validation methodology of the semantic and syntactic correctness of a single object-process diagram.