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OCR for page 71
71 for the time period the Operating System operates in failure different, the partial service credit incentive concept is very mode, the appropriate K factor shall be used. similar to the approach used for the Chicago O'Hare APM Fleet Availability discussed previously. One significant difference is that whereas the Chicago APM must deal with a specific approach For each time period and service mode of operation, Fleet Availability is measured as: due to its variable length trains, the CDG APM system does not (it has fixed-length trains). Both of these APM systems, Actual Car Hours Roissy Charles-de-Gaulle and Chicago O'Hare, are supplied A (f ) = Scheduled Car Hours by the same APM system manufacturer, Siemens, which may explain why the methods are similar, at least in the context of where each of the above terms has a precise technical definition partial service allowances. and is subject to recordation of actual conditions. Station Platform Door Availability 2.2.2 Theoretical Methods For each time period and service mode of operation, Station Platform Door Availability is measured as: The literature review and analysis have also revealed that APM performance measurement has been studied and reported Actual Platform Door Hours on theoretically. Three papers in particular have been presented A (s) = Scheduled Platform Door Hours in this area. where each of the above terms has a precise technical definition and is subject to recordation of actual conditions. APM Performance Measurement: Network Configuration System Service Availability and Service Availability For each time period (I), System Service Availability is mea- sured as: The first paper, "Airport APM Performance Measurement: Network Configuration and Service Availability," was pre- A ( I ) = Am ( I ) Af ( I ) As ( I ) sented in 2007 at the 11th International ASCE APM Confer- ence in Vienna [2.2.5]. It was written by Wayne D. Cottrell, where Am(I), Af(I) and As(I) are measured as described above. Associate Professor at California State Polytechnic University, and Yuko J. Nakanishi, President of Nakanishi Research and Consulting, LLC. Paris Airport Authority Method The paper examines service availability and reliability and The Paris Airport Authority (Aeroports de Paris) Method how they are affected by airport automated people mover is a variation on the System Dependability Method (ASCE) network configurations and other system parameters. The discussed previously. It was introduced by Aeroports de paper affirms the importance of availability and reliability Paris and ALONEX for Line 1 of the APM system at Roissy measurements in the APM industry that was discussed pre- Charles-de-Gaulle Airport [2.2.8]. Unlike the other methods, viously in Section 2.2.1: Applied Methods. it calculates contracted service availability on the basis of The paper suggests that detailed measures of headway service unavailability, and in so doing, eliminates from the regularity would be useful in an empirical study of AAPM calculation any need to consider grace periods or the down- reliability performance. Measures that are set forth include time exclusions common to the other methods. (The other headway adherence, service regularity, headway ratio, headway methods are similar in that they exclude the consideration regularity index, and headway deviation. of downtime caused by external sources, such as passenger- The ultimate conclusion is that network configuration affects induced delays, interruptions caused by intrusions of un the reliability and availability of airport APMs, albeit in a lim- authorized persons or objects, and other external sources ited way due to the limited variety of airport APM networks. beyond the control of the system or operating entity.) Other system parameters such as consist size and the number of Working from the perspective of service unavailability, the in-service trains also affect reliability and availability. goal of this method is to take into account the transporta- tion capacity of the system during periods of degraded mode and Measuring Service operations. Providing the ability to earn this partial service Availability for Complex credit, and tying the contracted service availability to payment, Transportation Networks is an incentive to the operator to provide the best possible transportation capacity during failures. Although the path The second paper, "Defining and Measuring Service Avail- to calculating the contracted service availability number is ability for Complex Transportation Networks," was presented