Troubleshooting in Mechanics: A Heuristic Matching Process

International audienceThis paper deals with expert operators' reasoning processes in troubleshooting. We want to know more about the information that experienced operators use. In a previous study we studied electronics troubleshooting. We found that experts used surface cues in order to implement heuristic rules even if the latter are not relevant to the current fault. We now wish to study the field of mechanics. An experiment was conducted in order to test the hypothesis of a heuristic rule-based level of control responsible for errors among experts. This paper adopts a naturalistic and ergonomic point of view about troubleshooting in mechanics. Our results show that expert mechanics operators' errors rely on heuristics in the troubleshooting process. This strategy relies on an automated matching process between symptoms and procedures. Although this strategy is usually powerful, it is rigid and may lead the operator to not locate the fault of the latter is atypica

'Here be dragons, here be savages, here be bad plumbing: Australian media representations of sport and terrorism

As 'Propaganda Theorists argue, an examination of key discourses can enhance our understanding of how economic, political and social debate is shaped by mainstream media reporting. In this essay we present content and discourse analysis of Australian media reporting on the nexus of sport and terrorism. Examining newspaper reports over a five-year period, from 1996-2001, which included the 11 September 2001 terrorist tragedy in the United States (9/11), provides useful insights into how public discourse might be influenced with regard to sport and terrorism interrelationships. The results of the media analysis suggest that hegemonic tropes are created around sport and terrorism. The distilled message is one of good and evil, with homilies of sport employed in metaphors for western society and its values. The reactions and responses of sport administrators and athletes to terrorist acts and the threat of terrorism to sport are used to exemplify these ideals, providing newspaper readers a context within which to localize meaning and relevance

Levels of abstraction in human supervisory control teams

This paper aims to report a study into the levels of abstraction hierarchy (LOAH) in two energy distribution teams. The original proposition for the LOAH was that it depicted five levels of system representation, working from functional purpose through to physical form to determine causes of a malfunction, or from physical form to functional purpose to determine the purpose of system function. The LOAH has been widely used throughout human supervisory control research to explain individual behaviour. The research seeks to focus on the application the LOAH to human supervisory control teams in semi-automated “intelligent” systems

Sub-lunar Tap Yielding eXplorer (STYX) & Surface Telemetry Operations and Next-generation Excavation System (STONES)

The NASA RASC-AL Moon to Mars competition challenges student teams to develop a lightweight, durable, and hands-off method for extracting water from Martian/lunar subsurface ice layers while mapping soil density profiles. Future interplanetary expeditions are dependent on the availability of clean water and this project aims to accomplish this task. The challenge description enumerates several criteria to be met for successful designs. For further information, the STYX & STONES team conducted research on Cal Poly’s competition project from last year to consider the areas for redesign. As such, the team has utilized the background research from relevant patents and journal articles to consider brainstorming potentially viable solutions. Based on these solutions for each subsystem, the team converged the ideas using a series of decision matrices into a final design direction. In addition to reviewing the STYX design, several new considerations were made for the scope of this project. Primarily, this year’s team focused on developing a prototype that has the capability of operating in an extraterrestrial environment and thoroughly fulfilling the requirements posed by NASA. To visualize the requirements, the team created a list of customer needs, a House of Quality diagram, and an engineering specifications table. Additionally, the STYX & STONES team discussed the design process it plans to follow including major project milestones. Specifically, the team plans to excel in collecting more than five quarts of water autonomously while successfully identifying the overburden layers – tasks that previous teams have struggled with. The team’s design direction includes two main components: a masonry drill bit and an auger- heater probe hybrid tool. The masonry drill bit will create a hole in the overburden using the force from a rotary hammer. The heater probe tool will then be moved to align with the hole and be driven into the loosened overburden using the force of a small gear motor. The heater probe will then melt ice using a hot waterjet and deliver water via a peristaltic pump and a two-stage filtration system. To verify the design, the team completed a multitude of analyses and tests for each subsystem and the prototype as a whole. Through drilling tests, the team found that the rotary hammer and masonry bit can easily cut through all overburden layers while keeping weight on bit (WOB) below 150N. Similarly, the load cells attached to the drill carriage were tested and proven to be accurate at recording WOB data and providing feedback to the controller to monitor WOB. Furthermore, the load cells proved successful at recording accurate WOB data that can be analyzed to determine overburden composition. The pumping system was also tested and was capable of effectively moving water through all filters and delivering fluid to the waterjet. More tests were completed to verify the heater probe tool; these tests included controlling heater temperature, melting ice, expelling water through the waterjet, and removing loose material from the hole. To verify the design requirements, the team has completed analysis pertaining to each subsystem including the drill, heater probe, frame, and control systems. The team is confident in the drilling design based on testing and vibrations analysis. In the same manner, the team verified that the 12V peristaltic pump will have enough pressure head rise based on analysis and prototype testing. Using the prototype heater probe as a reference, the team fully characterized the heat transfer parameters of the final design and is confident the auger will be effective considering surrounding debris. Finally, the team tested the water jet design using 120oF water which provided optimistic results that the water jet will significantly expand the melt radius per hole. As a next step, the team will be testing the mechanical and controls systems simultaneously using manufactured parts. The following report details the subsystems and relevant information

Coming to Terms with Engineering Design as Content

This article addresses the challenges posed by engineering design as a content area of technology education. What adjustments will technology teachers have to make in their approach to teaching and learning when they teach design as engineering in response to the new standards? How faithful to engineering as practiced must their approach be? There is already some advocacy in the literature that greater attention will need to be paid to mathematics and science, where these subjects underpin design. Cotton (2002) proposed that mathematical theories should be applied to design in technology education classrooms, and that students should be encouraged to use mathematics to predict the outcomes of their designs. Neumann (2003) suggested that students should spend more time engaged in research and redesign activities, as is the case in British schools. Roman (2001) encouraged an integrative approach to design that incorporates mathematics and applied science, in keeping with the cross-cutting nature of engineering. Afoot here is a discourse on curriculum integration that raises challenging questions for the field, including whether technology teachers as normatively trained are equipped to venture into the teaching of engineering design

Understanding Statutory ‘Regional management’ Functions and Assessing the Effectiveness of Regional Planning Management Practices in the Central Region of Ghana

Provisions of section 146 of the Local Government Act, 1993 (Act 462) on statutory ‘Regional management’ functions are not easily understandable in terms of what this actually entails. However, in effect, elements of the provisions are wider than stated. It does take some harrowing through to grasp the details. Moreover, other regional management functions are ‘indirectly’ provided in the Local Government Service Act, 2003 (Act 656). Identifying and putting all these together creates a full picture of regional management functions. Another issue is related to the effectiveness of regional planning management, at all. This study aims at identifying and understanding the details of statutory regional management and assessing the effectiveness of regional planning management practices, using the Central Region as a case. The effort and exercise corroborate formal field interactions and interviews with a representative Development Planner of the Regional Planning Co-ordinating Unit (RPCU) of the Central Regional Co-ordinating Council (CRCC). The overall details are, then, seen in terms of formal and professional management knowledge and both the tacit and enacted knowledge refocused into four main dimensions of management: ‘planning’, ‘organising’, ‘leading’ and ‘controlling’ functions. Effectiveness of regional planning management practices in the Central Region is assessed in terms of these dimensions and the contextual meaning of ‘management’. A number of proposals are made for resolving or ameliorating identified constraints and challenges. Keywords: Statutory Regional Management; Regional Planning Management Assessment; Regional Planning Management Effectiveness; Formal Management Knowledge; ‘Planning, ‘Organising’, ‘Leading’ and ‘Controlling’ Management Functions