Strategies for construction hazard recognition
Figure 4: Mathematical model selection flowchart for analysis
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- Validation using construction case images
| Figure 4: Mathematical model selection flowchart for analysis After the selection of the most suitable mathematical model, the coefficients of the regression equation provide the level change and slope change coefficients. By aggregating the change measures for all the three crews, the weighted overall level change can be computed using the reciprocal of error variance estimates as shown in Equation 3. πΏπΆ ππ£πππππ = β 1 π π 2 π πΏπΆ π π½ π=1 β 1 π π 2 π½ π=1 (3) Where J is the number of crews is the level change coefficent estimated for the jth crew is the estimated standard error for the jth level change coefficient Fit Models I and II using Ordinary least squares Model Comparison H 0 : Ξ² 1 = Ξ² 3 = Accept H 0 Test for autocorrelated errors H 0 :Ο 1 = Select Model II Reject H 0 Test for autocorrelated errors H 0 :Ο 1 = Accept H 0 Reject H 0 Select Model IV Accept H 0 Reject H 0 Select Model I Select Model III 61 Validation using construction case images In addition to the multiple baseline study tests we conducted a pretest and post-test using construction case images to obtain corroborative evidence. The pretest was conducted prior to providing the SAVES and mnemonics training and the post-test was conducted after the intervention following the sixteenth work period for each crew. The test involved selecting a random set of 8 photographs for the pretest and a different random set of 8 photographs for the post-test from a database of more than a hundred photographs. Prior to field testing the expert panel identified a comprehensive list of hazards for each photograph. The HR index for this validation effort was computed using Equation 4. Once the data were collected a two sample test for independent measures was used to compare performance. π»π = π» ππππ€ π» ππππ€ +π» πππππ (2) Where H crew is the number of hazards identified by the crew, and H crew + H panel is the total number of hazards identified by the crew and the research expert panel. Download 2.75 Mb. Share with your friends:
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