Correct predictions are in blue. If we detect only a subset of a labelled sentence, we highlight the caught part as blue, the missing part light blue. False positives are in green and false negatives are in red.

Problem Crew_Pairing — Constraint detection

The usual approach to the crew pairing optimization is to divide it into two subproblems . First , all legal pairings are built -LRB- pairing construction -RRB- and then a subset of pairings that covers all legs exactly once is selected -LRB- set partitioning problem -RRB- . The input to the pairing construction phase is the set of legs the airline company has to carry out . All legs are combined in sequences that respect the imposed constraints and , thus , they can be performed by a single crew . A pairing can last several days provided that there is the necessary rest time for the crew that carries it out . A basic constraint is that a pairing should start and end at the same airport . This airport is called base airport and it is at the place where the crew members employed by the airline company live . Other regulations and constraints that must be satisfied by each crew pairing are the following . Temporal constraints : there must be enough time between consecutive legs , so that every leg starts after the previous one has finished . Local constraints : the arrival airport of a leg must be the same with the departure airport of the succeeding leg . Flight Duty Time -LRB- FDT -RRB- : FDT is the time during which a crew member operates on an aircraft as a member of its crew : this parameter must not exceed a certain number of hours . Number of legs per working day and number of legs per pairing : upper bounds exist for both these factors . The phase responsible for the set partitioning problem accepts the created pairings which have been also assigned a cost . The cost is usually related with the crew utilization . The system selects those pairings that cover all flight legs with the minimum cost . It should be noted that each leg must belong to only one pairing and each pairing must contain every leg at most once . Pairings last several days , although legs may be performed once every day .

Problem Crew_Pairing — Detection of the decisions and objects to be modeled

The usual approach to the crew pairing optimization is to divide it into two subproblems . First , all legal pairings are built -LRB- pairing construction -RRB- and then a subset of pairings that covers all legs exactly once is selected -LRB- set partitioning problem -RRB- . The input to the pairing construction phase is the set of legs the airline company has to carry out . All legs are combined in sequences that respect the imposed constraints and , thus , they can be performed by a single crew . A pairing can last several days provided that there is the necessary rest time for the crew that carries it out . A basic constraint is that a pairing should start and end at the same airport . This airport is called base airport and it is at the place where the crew members employed by the airline company live . Other regulations and constraints that must be satisfied by each crew pairing are the following . Temporal constraints : there must be enough time between consecutive legs , so that every leg starts after the previous one has finished . Local constraints : the arrival airport of a leg must be the same with the departure airport of the succeeding leg . Flight Duty Time -LRB- FDT -RRB- : FDT is the time during which a crew member operates on an aircraft as a member of its crew : this parameter must not exceed a certain number of hours . Number of legs per working day and number of legs per pairing : upper bounds exist for both these factors . The phase responsible for the set partitioning problem accepts the created pairings which have been also assigned a cost . The cost is usually related with the crew utilization . The system selects those pairings that cover all flight legs with the minimum cost . It should be noted that each leg must belong to only one pairing and each pairing must contain every leg at most once . Pairings last several days , although legs may be performed once every day .

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