Christine Zupanc

Directional control–response compatibility of joystick steered shuttle cars

Shuttle cars are an unusual class of vehicle operated in underground coal mines, sometimes in close proximity to pedestrians and steering errors may have very serious consequences. A directional control–response incompatibility has previously been described in shuttle cars which are controlled using a steering wheel oriented perpendicular to the direction of travel. Some other shuttle car operators are seated perpendicular to the direction of travel and steer the car via a seat mounted joystick. A virtual simulation was utilised to determine whether the steering arrangement in these vehicles maintains directional control–response compatibility. Twenty-four participants were randomly assigned to either a condition corresponding to this design (consistent direction), or a condition in which the directional steering response was reversed while driving in-bye (visual field compatible). Significantly less accurate steering performance was exhibited by the consistent direction group during the in-bye trials only. Shuttle cars which provide the joystick steering mechanism described here require operators to accommodate alternating compatible and incompatible directional control–response relationships with each change of car direction. Practitioner Summary: A virtual simulation of an underground coal shuttle car demonstrates that the design incorporates a directional control–response incompatibility when driving the vehicle in one direction. This design increases the probability of operator error, with potential adverse safety and productivity consequences.

Reducing control selection errors associated with underground bolting equipment.

Selecting the incorrect control during the operation of underground bolting and drilling equipment causes serious injuries. Shape coding and the layout of dual control banks are two aspects of control design which require further examination. The aims of this research were: (i) to determine whether arbitrary shape coding was effective in reducing selection error rates in a virtual analogy of roof-bolting; and (ii) to determine whether any advantages exist for mirror or place layouts for dual control situations in this situation. Two experiments were conducted to address these questions. No benefits of arbitrary shape coding were evident while control location remained constant. When control location was altered, shape coding did provide a significant reduction in selection error rate. No differences between mirror or place arrangements were detected and this question remains open.

A competency framework for colonoscopy training derived from cognitive task analysis techniques and expert review.

BackgroundColonoscopy is a difficult cognitive-perceptual-motor task. Designing an appropriate instructional program for such a task requires an understanding of the knowledge, skills and attitudes underpinning the competency required to perform the task. Cognitive task analysis techniques provide an empirical means of deriving this information.MethodsVideo recording and a think-aloud protocol were conducted while 20 experienced endoscopists performed colonoscopy procedures. “Cued-recall” interviews were also carried out post-procedure with nine of the endoscopists. Analysis of the resulting transcripts employed the constant comparative coding method within a grounded theory framework. The resulting draft competency framework was modified after review during semi-structured interviews conducted with six expert endoscopists.ResultsThe proposed colonoscopy competency framework consists of twenty-seven skill, knowledge and attitude components, grouped into six categories (clinical knowledge; colonoscope handling; situation awareness; heuristics and strategies; clinical reasoning; and intra- and inter-personal).ConclusionsThe colonoscopy competency framework provides a principled basis for the design of a training program, and for the design of formative assessment to gauge progress towards attaining the knowledge, skills and attitudes underpinning the achievement of colonoscopy competence.

Effect of Age on Learning to Drive a Virtual Coal Mine Shuttle Car

Many control devices produce movements that can be described as compatible, that is, movement of the control in one direction results in a congruent movement in the system. However, not all devices adhere to this direct relationship between control movement and system response. This study investigates age and practice effects on error and reaction times for a real-world vehicle steering system in which steering is not consistently compatible. A virtual reality simulation analogous to an underground coal mine shuttle car was used to collect short term (experiment 1) and longer term (experiment 2) practice where trials alternate between compatible and incompatible, and then changed to consistently compatible. Fifteen young and 15 older male adults participated in experiment 1, and 7 young and 7 older male adults participated in experiment 2. Younger adults made fewer errors in incompatible trials than older adults in experiment 1. Error rate increased for both groups when the trials changed to consistently compatible. No differences in reaction time were found. With more practice, no differences in error rate were found between the groups (experiment 2). Both errors and reaction time increased when the the trials changed to consistently compatible. This research suggests that performance differences between male adults close to retirement age and younger male adults may dissipate after practice. Performance decrements were found when the control-response relationship changed from alternating compatibility to consistently compatible, therefore, care must be taken in redesigning incompatible controls when operators may have achieved a high level of expertise.

Effect of control order on steering a simulated underground coal shuttle car

Most terrestrial vehicles are steered via a first-order control for vehicle heading, such as a conventional steering wheel. A joystick which provides second-order control of vehicle heading is used to steer some underground coal shuttle cars. A desktop virtual simulation of the situation was employed to compare the steering accuracy of 24 novice participants randomly assigned to either first-order or second-order joystick steering conditions. The average steering accuracy of participants assigned to the first-order joystick condition was superior, however there was considerable individual variability and some participants assigned to the second-order steering condition were able to perform the task equally and successfully. Desktop virtual simulation may be a useful component of training and competency assessment for operators of these vehicles.

Control Order and Visuomotor Strategy Development for Joystick-Steered Underground Shuttle Cars

Objective: In this simulator-based study, we aimed to quantify performance differences between joystick steering systems using first-order and second-order control, which are used in underground coal mining shuttle cars. In addition, we conducted an exploratory analysis of how users of the more difficult, second-order system changed their behavior over time. Background: Evidence from the visuomotor control literature suggests that higher-order control devices are not intuitive, which could pose a significant risk to underground mine personnel, equipment, and infrastructure. Method: Thirty-six naive participants were randomly assigned to first- and second-order conditions and completed three experimental trials comprising sequences of 90° turns in a virtual underground mine environment, with velocity held constant at 9 km/h−1. Performance measures were lateral deviation, steering angle variability, high-frequency steering content, joystick activity, and cumulative time in collision with the virtual mine wall. Results: The second-order control group exhibited significantly poorer performance for all outcome measures. In addition, a series of correlation analyses revealed that changes in strategy were evident in the second-order group but not the first-order group. Conclusion: Results were consistent with previous literature indicating poorer performance with higher-order control devices and caution against the adoption of the second-order joystick system for underground shuttle cars. Application: Low-cost, portable simulation platforms may provide an effective basis for operator training and recruitment.

Steering Performance and Dynamic Complexity in a Simulated Underground Mining Vehicle

Research concerning the visuomotor control of steering suggests that some steering systems used in underground shuttle cars are not optimal. This research compared the performance of two groups of participants steering with a joystick interface through a simulated underground mine environment. The joystick employed either first-order or second-order control of heading. Results indicated poorer performance with second-order steering dynamics in the early stages of the experiment, which generally did not improve to levels observed in the first-order group. Poorer overall performance suggests that equipment manufacturers should reconsider the use of second-order steering dynamics in their vehicle designs. Alternately, simulation-based training technologies may have the potential to safely accelerate individual attainment of competence in the use of second-order steering systems.

Strategy influences directional control–response compatibility: evidence from an underground coal mine shuttle car simulation

This paper examines the influence which participants’ task strategy has on directional control–response compatibility. Two experiments are reported in which participants were grouped according to the strategies they reported using while driving a simulated analogy of an underground coal mine shuttle car. In Experiment 1, compatibility effects were found for participants who reported adopting the wheel-referenced instruction. No reaction time compatibility effects were observed for participants who adopted a rule-based strategy for all trials. Participants were given rule-based instruction in Experiment 2. Seven participants followed the instruction, and no reaction time compatibility effect was observed. However, 15 participants reported adopting a wheel-referenced strategy during ‘compatible’ trials, and directional compatibility effects were found. In summary, regardless of the instructions provided during experimental situations, individuals may identify action features which they consider helpful in achieving the task goal, and these different strategies influence directional control–response compatibility.

The development and validation of a colorectal polyp recognition test

Diminutive” colonic polyps are by defi nition polyps that are 5 mm or less in size. Previous studies suggest that such polyps are of low risk for malignancy. However, improvements in optical imaging and image resolution (High Defi nition Endoscopy) coupled with increased operator awareness have resulted in a higher detection rate at colonoscopy. Past studies suggest that high grade dysplasia may occur up to a rate of 4% in these polyps. Methods Patients referred to a single Tertiary Institution for screening colonoscopy after detection of a positive FHH. All patients referred between 2009 and 2010 were included in this retrospective study. The patients were referred either through the National Bowel Cancer Screening Program or through GP initiated screening. Polyps were measured after the tissue was placed in formalin (histological size). For each colonoscopy the predetermined aim was to resect all polyps and to submit them to histological assessment. Results A total of 307 patients were investigated. NBCSP referred (41%) and GP initiated FOBT (59%). Male : Female (1.1:1). 148 (48%) patients showed a total of 258 polyps. 62% of polyps were size <5 mm, 22% were 5–9 mm and 16% were 10 mm or greater. The histological features of the polyps <5 mm were 56% tubular adenomas (TA), 7.5% were TVA and 0.6% were VA. Only 30% of polyps <5 mm were hyperplastic in nature. One TA showed high grade dysplasia (0.6%). No carcinoma was found in polyps <5 mm. A total of 11 (3.6%) carcinomas were identifi ed, 2/11 were in polyps >10 mm size and one in the 5–9 mm size. We also identifi ed the position of the polyp (<5 mm) according to left and right colonic classifi cation. 51% were left sided, 14%were right sided, location not specifi ed in 35%. Conclusion: In patients who are positive for FHH the incidence of diminutive polyps is considerable and importantly there is a signifi cant proportion of adenomatous polyps. Based on these fi ndings we believe that diminutive polyps should be resected and that they be followed up appropriately. Differences in bowel preparation for colonoscopy between ethnic groups S SETHI Bankstown Day Surgery, Sydney Introduction Suboptimal bowel preparation can result in missed lesions, aborted procedures and increases in cost and complication rates. The quality of bowel preparation can vary among patients depending on factors such as age, time of the day when colonoscopy is performed, literacy and inpatient status. There is a paucity of literature about the difference between ethnic groups in the quality of bowel preparation. Differences in literacy, diet and cultural factors may affect bowel preparation. The aim of this study was to determine whether the quality of bowel preparation differs among racial groups. Methods This was a retrospective study looking at 100 patients each undergoing colonoscopy from East Asia (China/Japan/South Korea/ Vietnam/Thailand), the Indian subcontinent (India/Bangladesh/Pakistan), United Kingdom, Southern Europe (Italy/Greece) and Arabic origin patients. Patients were contacted by telephone and classifi ed into an ethnic group. Patient related data was extracted from case notes. All patients were instructed to follow a standardized protocol of bowel preparation involving a low residue diet for 2 days and prep kit C the evening before the procedure. The quality of bowel preparation was graded by the endoscopist during the procedure and classifi ed as excellent, good, average or poor. These were then classifi ed as being either satisfactory (excellent/good) or unsatisfactory (average/poor). All were outpatients in a community day surgery setting and were performed in the morning. Results The groups did not differ signifi cantly in terms of age/sex. SATISFACTORY UNSATISFACTORY UNITED KINGDOM 87% 13% SOUTHERN EUROPE 84% 16% INDIAN SUBCONTINENT 76% 24% ASIAN 83% 17% ARABIC 81% 19% The Indian group had signifi cantly poorer bowel preparation as compared to the United Kingdom Group (p 0.002). There was no statistically signifi cant difference between the other groups. Discussion The poor bowel preparation of the Indian group may be due to factors such as poor English language profi ciency, diet and socioeconomic status. Hence, the Indian group may benefi t from more precise instructions and a more rigorous bowel preparation regime. Future studies should be performed to identify how ethnic factors affect bowel preparation. Journal of Gastroenterology and Hepatology (2011) 26 (Suppl. 4)

The effects of augmented visual feedback on motor skill learning in colonoscopy

The nature and outcomes of ERCP may vary depending on the referral population. In this retrospective audit we report the outcomes of ERCP in a community hospital. Methods Patients who underwent ERCP at Frankston Hospital between November 2009 and April 2010 were included in a retrospective audit. Demographics, procedure details and complications were identifi ed using endoscopy archives and patient records. Results 117 procedures were undertaken in 113 different patients using the short-wire technique. Median age was 69 years (range = 19–90) and 60% (70/117) were female. Most of the procedures were undertaken in inpatients (61%, 81/117). Common indications for ERCP were: proven or suspected choledocholithiasis in 51% (60/117), biliary strictures in 9% (11/117), ascending cholangitis in 8% (9/117), obstructive jaundice in 8% (9/117), pancreatitis in 7% (8/117) or pancreatic masses in 6% (7/117). Twenty-nine per cent (34/117) of patients had a previous sphincterotomy. Deep common bile duct cannulation was possible in 92% (106/115) of procedures. In 78% (90/117) endoscopic sphincterotomy was performed and in 9% (10/117) needle knife sphincterotomy was undertaken. The most common interventions included: stone extraction in 39% (46/117), stenting in 16% (19/117), removal of stent in 7% (8/117) and dilation of strictures in 2% (2/117). The following complications were observed: bleeding (immediately after sphincterotomy) in 3% (4/117), non-pancreatitis related abdominal pain in three patients and one case each of delayed bleeding, cholangitis and pancreatitis. Summary This series suggests that the outcomes of ERCP in an outer metropolitan hospital are favourable with a low rate of observed complications. The morphological assessment of large sessile polyps and laterally spreading tumours (LST) of the colon: an educational exercise assessing current knowledge and the learning curve M NAIDOO, R SINGH, A MOSS, W TAM, MJ BOURKE Gastroenterology Departments, Westmead Hospital, Sydney, Lyell McEwin Hospital, Adelaide, Australia Background and Aims The Paris Classifi cation system (PCS) in combination with lesion granularity (LG) is effective for stratifying risk of sub-mucosal invasion and thus informing treatment strategies for LST of the colon. However, despite being the accepted standard practiced by experts in the fi eld and universally utilized in scientifi c publications, it is apparently underused in general endoscopic practice and the baseline level of knowledge and learning curve for this system is currently unknown. Methods Amongst 160 medical delegates attending a national endoscopy symposium, 50% were randomly selected and emailed an educational package on PCS and LG for colonic LST 4 days prior. A standardised test consisting of 20 typical colonic LST was formulated and unanimously agreed by a panel of four blinded endoscopists with signifi cant LST experience. Disputed lesions were excluded. The test was posed to all delegates at the conference. Amongst respondents, results were scored according to the correct identifi cation of lesions by PCS and granularity. Results 72 delegates participated in the test, of which 13 were not scored due to nil attempts. The reported mean time to assimilate the information contained in the package was 12.2 min (range 5–40). Those who received the package were more likely to completely attempt PCS vs non-recipients (90.5% vs 49.5%, p < 0.001) and LG (90.5% vs 66.7%, p = 0.019). Median correct PCS responses were 9/20 in recipients (InterQuartileRange 3/20– 13/20) vs 3/20 in non-recipients (IQR 1/20–8/20, p = 0.009). LG assessment of recipients (median 17/20, IQR: 15/20–19/20) and non-recipients (median 15.5/20, IQR: 11/20–18/20) was not signifi cantly different (p = 0.112). There was no signifi cant difference in correct responses between delegates with varying levels of annual colonosocopy volume, total colonoscopy or endoscopic mucosal resection experience. Conclusions Baseline level of PCS knowledge amongst practicing endoscopists is poor. A simple easily disseminated learning tool signifi cantly enhances understanding and application of the PCS but this is still not to an accuracy that is required for everyday clinical use. National dissemination of such a learning tool may result in improved risk stratifi cation of colonic LST, however a simpler re-classifi cation of the current system may also be needed.