Ergonomics investigation of retail ice cream operations

A comprehensive ergonomics evaluation of retail ice cream shops, including field and laboratory data collection, was conducted using a human:workplace model approach to ergonomics practice. The goal of the evaluation was to provide recommendations to enhance the health, safety, and productivity of shop employees. Active and passive surveillance and facility walk-throughs were used to guide the selection of analyses. A primary focus of the investigation was quantifying the task demands of scooping ice cream, which have not been documented in the literature. This goal was accomplished through the use of a custom-designed instrumented ice cream scoop. Data were collected at an ice cream shop under typical conditions, while the laboratory experiment investigated task demands of ice cream scooping over a range of realistic temperatures. Manual materials handling task analyses and anthropometric evaluations comprised the majority of other analyses performed. Recommendations are presented that are applicable to the operation of retail ice cream shops that serve hard (i.e., scooped) ice cream.     

Development of a work seat for industrial sewing operations: results of a laboratory study

A hydraulically adjustable chair with seven independent variables - seat height, seat angle, seat rocking, seat swivel, back-rest distance, back-rest height and back-rest angle-was constructed to evaluate comfort and biomechanical factors relevant to the design of a chair for industrial sewing operations. The purpose of this investigation was to determine which of these factors were significant. Four assessment methods: overall body discomfort, localized body discomfort, electromyography (EMG) and height reduction (vertebral disc shrinkage) were used to evaluate these seven independent variables. Two female subjects attended eight 6 hour experimental sessions. The results indicate that to accommodate 90% of the female population, the seat height should be adjustable in the range 51 to 61 cm, the back-rest distance should be adjustable in the range 10 to 15 cm (measured from the centre of the back-rest to the centre of the seat-pan), the back-rest height should be fixed at 25 cm (measured from the centre of the back-rest to the centre of the seat-pan), and the seat should be allowed to swivel freely.     

Fast multiresolution image operations in the wavelet domain

A wide class of operations on images can be performed directly in the wavelet domain by operating on coefficients of the wavelet transforms of the images and other matrices defined by these operations. Operating in the wavelet domain enables one to perform these operations progressively in a coarse-to-fine fashion, operate on different resolutions, manipulate features at different scales, trade off accuracy for speed, and localize the operation in both the spatial and the frequency domains. Performing such operations in the wavelet domain and then reconstructing the result is also often more efficient than performing the same operation in the standard direct fashion. In this paper, we demonstrate the applicability and advantages of this framework to three common types of image operations: image blending, 3D warping of images and sequences, and convolution of images and image sequences.     

Evaluating design proposals for complex systems with work domain analysis

In this paper we propose a new framework for evaluating designs based on work domain analysis, the first phase of cognitive work analysis. We develop a rationale for a new approach to evaluation by describing the unique characteristics of complex systems and by showing that systems engineering techniques only partially accommodate these characteristics. We then present work domain analysis as a complementary framework for evaluation. We explain this technique by example by showing how the Australian Defence Force used work domain analysis to evaluate design proposals for a new system called Airborne Early Warning and Control. This case study also demonstrates that work domain analysis is a useful and feasible approach that complements standard techniques for evaluation and that promotes a central role for human factors professionals early in the system design and development process. Actual or potential applications of this research include the evaluation of designs for complex systems.     

Real-time use of ERS-l SAR imagery for ice service and ice breaking operations in the Baltic Sea

Sea ice forms every winter in the Baltic Sea and several icebreakers in Sweden and Finland keep the major ports in the area open for sea-trade all the year around. Information and forecasts of the sea ice formation, drift and deformation are vital for safe and efficient winter navigation. In this respect, Synthetic Aperture Radar (SAR) imagery is of great interest, since this technique is almost cloud independent and has potential for real-time ice mapping. The usefulness of SAR imagery for sea ice operations has been evaluated in the Baltic Sea. The imagery was used both for ice mapping, for icebreaker operations and ship routeing. Images presented onboard the icebreakers were highly appreciated and easily interpreted by the crew. The data were frequently used for ship routeing (33 per cent) of merchant vessels and for direct icebreaker assistance (53 per cent). It was concluded by several icebreaker masters that an image resolution of about 100m was indeed enough to distinguish ridged areas and in the same time obtain a large enough geographical coverage per image.     

ToolDAy: a tool for domain analysis

Domain analysis is the process of identifying and documenting common and variable characteristics of systems in a specific domain. This process is a large and complex one, involving many interrelated activities, making it essential to have a tool support for aiding the process. We present a domain analysis tool called ToolDAy that has the purpose of making the process semi-automatic. The requirements definition presented were based on the results of a systematic review that analyzed several existing tools. Furthermore, this article describes the tool architecture, implementation and its evaluations (two as a controlled experiment and one as an industrial case study) with three different domains. The results of these evaluations indicate that the tool can aid the domain analyst to achieve systematic reuse in an effective way.     

A work domain analysis framework for modelling intensive care unit patients

Work domain analysis (WDA) has been applied to a range of complex work domains, but few WDAs have been undertaken in medical contexts. One pioneering effort suggested that clinical abstraction is not based on means-ends relations, whereas another effort downplayed the role of bio-regulatory mechanisms. In this paper it is argued that bio-regulatory mechanisms that govern physiological behaviour must be part of WDA models of patients as the systems at the core of intensive care units. Furthermore it is argued that because the inner functioning of patients is not completely known, clinical abstraction is based on hypothetico-deductive abstract reasoning. This paper presents an alternative modelling framework that conforms to the broader aspirations of WDA. A modified version of the viable systems model is used to represent the patient system as a nested dissipative structure while aspects of the recognition primed decision model are used to represent the information resources available to clinicians in ways that support if...then conceptual relations. These two frameworks come together to form the recursive diagnostic framework, which may provide a more appropriate foundation for information display design in the intensive care unit.Abbreviations ADS Abstraction decomposition space - DST Dissipative structures theory - HIV/AIDS Human immunodeficiency virus/acquired immunodeficiency syndrome - ICU Intensive care unit - RDF Recursive diagnostic framework - RPD Recognition primed decision model - R-VSM Revised viable systems model - VSM Viable systems model - WDA Work domain analysis     

Making drilling operations visible: the role of articulation work for organisational safety

In the petroleum industry, new technologies and work processes are currently being developed as an innovation strategy for better, faster and safer drilling. In this article, some features of today’s work processes that contribute to successful operations are presented and discussed. The articulation work involved in handling the transient complexity of operations involves making black-boxed and invisible work processes visible and transparent. It is argued that this articulation work contributes to the organisation’s understanding and knowledge of the drilling processes and the dependencies that exist between different actors. In addition to contributing to ongoing problem solving, the articulation work also contributes to the awareness of possible future events. Following this insight, it is argued that efforts to improve operational efficiency and safety by introducing new tools and work processes should focus not only on the capability of new tools to support decisions and actions by instrumentation and automation, but attention should also be paid to the existing articulation work and its role in the accomplishment of work. In that way, the contributions of today’s articulation work can be strengthened instead of lost, and the outcome of the change processes can be even better than anticipated.     

Constraint analysis: a design process for specifying operations onobjects

A design process for an object-oriented database design environment, known as constraint analysis, is presented. Given the increased level of semantics associated with an object-oriented database schema, constraint analysis makes use of semantics expressed as database constraints to support the flexible specification of propagation actions for operations on objects. Constraints are formally represented using Horn logic. The constraint analysis process then reasons about constraints at design time to help the designer understand the effects of constraints on object manipulation, identifying possible constraint violations as well as design alternatives for handling violations. An advantage of constraint analysis is that both inherent and explicit schema constraints are included in the analysis process. A formal representation is given that supports the analysis of constraints and the automatic identification of design alternatives for responding to constraint violations     

Evaluation of a new work seat for industrial sewing operations: results of three field studies

A newly developed work seat for industrial sewing operations was compared with a traditional sewing work seat to evaluate the effectiveness of design features. The new seat was designed with special seat-pan and backrest features to accommodate the musculoskeletal geometry of a low sit-stand posture. The seat-pan consisted of a pelvic support which supported the ischial tuberosities and areas behind them, and a thigh support which maintained the thighs at a 15 degrees downward angle, resulting in a 105 degrees trunk-thigh angle. The backrest consisted of a lumbar support which preserved lumbar lordosis and a thoracic support which supported the upper back during backward leaning. The traditional work seat was similar to an office chair (i e, a large horizontal seat-pan and a wide backrest) with the exception of having a higher than normal seat-height. This investigation consisted of three studies to compare the seats: (1) A user comfort and acceptance experiment which compared the initial psychophysical responses of 50 industrial sewers when introduced to the new seat; (2) a backrest usage experiment which compared the duration of backrest use among 10 industrial sewers; and (3) a follow-up experiment to evaluate chair preference after extended use of the new seat. The results of the user comfort and acceptance experiment found that the new work seat had greater comfort and user preference; the results of the backrest usage experiment found that the new seat had greater backrest use than the traditional seat; the results of the follow-up experiment found that the preference for the new seat was maintained over time and not due to a Hawthorne Effect.     

Enhanced ground support: lessons from work on reduced crew operations

Cognition, Technology & Work - From the 1950s through the 1980s, aircraft design was marked by an increase in reliability and automation, and, correspondingly, a decrease in the crew complement...     

Lessons from a comparison of work domain models: representational choices and their implications

As methods in cognitive work analysis become more widely applied, questions regarding the impact of modeling choices and similarities in modeling efforts across projects and domains are increasingly relevant. However, no explicit comparison of models of similar systems has been reported. This paper compares independently developed work domain analysis (WDA) models of two command and control environments. Similarities in model content and the types of nodes included provide evidence that WDA techniques can capture fundamental elements regarding purposes and constraints. These points of agreement provide a common starting point for developing work domain representations of military command and control systems. The comparison also revealed differences between the models. Although differences in content reflected differences in scope of coverage and level of detail, other differences corresponded to more fundamental choices in modeling approach. These included the treatment of sensors, level of integration in the model, and representation of particular abstract constraints. Examination of these more fundamental differences pointed to important degrees of freedom in how to represent a WDA and clarified the implications of these modeling choices for guiding design. Actual or potential applications of this research include aiding analysts in making work domain modeling choices as well as producing work domain models of command and control environments.     

Utilizing Event-B for domain engineering: a critical analysis

This paper presents our experience of modeling land transportation domain in the formal framework of Event-B. Well-specified requirements are crucial for good software design; they depend on the understanding of the domain. Thus, domain engineering becomes an essential activity. The possibility to have a formal model of a domain, consistent with the use of formal methods for developing critical software working within it, is an important issue. Safety-critical domains, like transportation, exhibit interesting features, such as high levels of nondeterminism, complex interactions, stringent safety properties, and multifaceted timing attributes. The formal representation of these features is a challenging task. We explore the possibility of utilizing Event-B as a domain engineering tool. We discuss the problems we faced during this exercise and how we tackled them. Special attention is devoted to the issue of the validation of the model, in particular with a technique based on the animation of specifications. Event-B is mature enough to be an effective tool to model domains except in some areas, temporal properties mainly, where more work is still needed.     

Cooperative work in mission operations: Analysis and implications for computer support

This paper describes cooperative work in real-time flight operations in the SAMPEX Mission Operations Room at NASA Goddard Space Flight Center. This domain is an example of distributed supervisory control, where a team of human operators supervises a dynamic, complex, highly automated system. Such operational environments differ in important ways from artifact-centered collaboration (e.g., collaborative drawing, writing, design). This paper explores those differences and also articulates the need for activity management tools for dynamic control environments. Candidate models from the human-machine systems engineering literature are proposed to provide the underlying structure for such tools.     

Perception of heavy work operations by tank truck drivers

Seven male tank truck drivers were followed for about 3 h during ordinary work. They rated the perception of heavy work operations on Borg's CR-10 scale. The heart rates were monitored every minute. The hose was pulled out an average of 22.3 m and the corresponding mean rating was 3.2, a little bove ‘Moderate’ on the CR-10 scale. The heart rate averaged 137 beats/min at the end of this operation. When transforming the physiological parameter heart rate to a subjective strain intensity, surprisingly high agreement was obtained between the results from the field study and the predicted ratings. By transforming ordinally scaled data from another study to a scale with ratio properties, the results could be compared with this study. Good agreement was found between the variables.     

Command and control in emergency services operations: a social network analysis

There is increasing interest in the use of social network analysis as a tool to study the performance of teams and organizations. In this paper, processes of command and control in the emergency services are explored from the perspective of social network theory. We report a set of network analyses (comprising visualization, a selection of mathematical metrics, and a discussion of procedures) based on the observation of six emergency service incidents: three fire service operations involving the treatment of hazardous chemicals, and three police operations involving immediate response to emergency calls. The findings are discussed in terms of our attempts to categorize the network structures against a set of extant command and control network archetypes and the relationship between those structures; comments on the qualities the networks display are put into the contexts of the incidents reported. We suggest that social network analysis may have a valuable part to play in the general study of command and control.     

Convergence analysis of a domain decomposition paradigm

We describe a domain decomposition algorithm for use in several variants of the parallel adaptive meshing paradigm of Bank and Holst. This algorithm has low communication, makes extensive use of existing sequential solvers, and exploits in several important ways data generated as part of the adaptive meshing paradigm. We show that for an idealized version of the algorithm, the rate of convergence is independent of both the global problem size N and the number of subdomains p used in the domain decomposition partition. Numerical examples illustrate the effectiveness of the procedure.     

The use of operational event sequence diagrams and work domain analysis techniques for the specification of the crewing configuration of a single-pilot commercial aircraft

Cognition, Technology & Work - Aircraft manufacturers and avionics systems suppliers are developing technologies for airliners that will be operated by just a single crew member. An alternative...     

Economic analysis of robotic operations: A case study of a thermal spraying robot

There is growing interest in the industrial applications of computer-integrated manufacturing (CIM) and robotic technology. The economic analysis methods which are currently available to assess the cost effectiveness of robotic systems are, however, limited. This paper presents a methodology to address this issue. To demonstrate the methodology, a case-study is presented which uses a thermal spraying robot in a rapid tool manufacturing system. The interdependencies between tolerance, robot accuracy, and the probability of a successful spraying operation are demonstrated. The economic effects of using robots in the spraying process are analyzed. Analytical models are developed to estimate the productivity of components without any defects and the improvement in tool life attributable to robotic spraying. The economic analysis method presented in the paper is also applicable to other operations such as robotic assembly and robotic welding.