【正文】 and previous record was outside the area for enter times, or the next record is outside the area for exit times.The FBTIM first evaluates position to determine whether therecorded position is within defined boundaries. Then it determines whether the record represents an enter or exit time by examining the status of the previous or next record. The user defines the boundaries on the FBTIM input dialog box and may define as many as 4 areas by providing a minimum and maximum value for both northing and easting coordinates for each area. The values are used to evaluate each recorded position and mark it as in or out of each area. The times of entry and exit are then identified and summarized.Case StudyThe system was field tested by collecting data from three Caterpillar 771 quarry trucks and a 988 rubbertired loader used to move material at a local aggregate quarry. Shot rock was hauled to crushers, while overburden material was hauled to an onsite waste area. Three load areas and three dump areas were identified: the load areas were active rock faces, while the dump areas consisted of two rock crusher bins and the waste area.The system was installed on four pieces of equipment and wired through the ignition switch, which allowed the system to operate only when the equipment was operating. The equipment battery provided a reliable power source. Data were collected over several days and recorded at a 2s time interval. The equipment operated approximately 11 h each day, thereby producing approximately 19,800 records daily. This large volume of recorded data resulted in a clear need for automated data reduction methods.The system simply and efficiently recorded position and velocity. The challenge became how to present the data in a graphical format for a preliminary review and then to identify and select the relatively small number of key records needed to calculate activity times. A preliminary review is necessary for the user to evaluate the data to determine in which activities the truck was engaged and the location of each activity.Graphical data representations and knowledge of the projectare the most appropriate sources from which to gather this information. The areas in which earthmoving activities were performed can be determined based on knowledge of the project and a plan view of the data. The truck from which the sample data were obtained moved material from two separate loading areas to two separate dumping areas.Fig. 3 shows that the truck was engaged in three separate operations, the first two of which are of importance (a single cycle of the third operation was performed and is therefore of little importance). Five loads were hauled approximately 800 m between 10:20 and 11:30 in the first operation, and a second hauling operation hauled 36 loads a distance of approximately 100 m between 10:30 and 20:20.Therefore, 2 load and haul operations consisting of 4 activities (load, haul, dump, and return) each were identified from the preliminary review. The activitynaming convention adopted for this work is the activity name followed by the associated areas. For example, loading in area 3 is labeled Load 3, while hauling from load area 1 to dump area 2 is labeled Haul 12. The TIMs were applied to the data to identify the beginning and end times for each of the identified activities.The dump activities occur in fixed locations and with zero velocity, and therefore the ADTIM was used to identify the records key to those activities. The ADTIM areas to be applied to the data are shown in Fig. 5. The user can determine the central coordinates and radial distance of each ADTIM area from the plan view of the recorded data. Once the input data are provided,the ADTIM is executed and the results are placed on an ADTIM sheet. A portion of the ADTIM results for the Dump 2 activity are provided in Table 2.The results obtained should be pared with the preliminary review results to verify the ADTIM process and ensure that the total instances and time frame of the associated activities concur with the results of the preliminary review. A total of approximately 18,850 data records were collected and analyzed. The set of records where velocity equaled zero numbered approximately 13,900, a reduction of approximately 25%. Further reduction by ADTIM identified 90 key records that mark the start and end of activities. These 90 records represent less than % of the total records collected, and thus the collected data were reduced by more than %.The EXTIM was used to identify the records key to the load activities because the area in which the truck was loaded changed over time. The data file recorded on the loader was used with a critical distance of 20 m. This distance was selected based on previous experience with data from the same or similar operations.It is also necessary to review the EXTIM results to identify and eliminate any extraneous results. Such results can be produced by actions occuring outside of time frames identified during data evaluation and by trucks queuing at the loader at a distance less than the specified critical distance. Results outside an operational time frame are easily identified。 spent with velocity equal to zero within a fixed distance of a moving location—., a haul truck loading at a loader。Time studies.IntroductionTime studies historically have been performed to record the time required to plete various construction tasks (Oglesby et ). The original time study system was the stopwatch, which has since been replaced by timelapse video recordings. These systems are manual in nature and limited to the field of view of the observer, or what is within the line of sight of the , analysts have turned to technology for new an observer performs the study in the field with a stopwatch or the operation is filmed for preliminary review and data reduction in the office, the information is limited to the field of view of the observer or camera. A