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 115 (Tail Assignment) — Constraint detection

Tail Assignment is the problem of deciding which individual aircraft -LRB- identified by its tail number -RRB- should cover which flight . Each aircraft is thus assigned a route consisting of a sequence of flights , and possibly other activities such as maintenance , to perform . Tail Assignment deals with individual constraints , flights which are fixed in time , as well as individual rules for each tail . The planning period is typically one month . The purpose is to really create a solution that is possible to operate , satisfying all rules and regulations . The most basic rules are rules which only depend on two flights , so-called connection-based rules . For example , there must be a certain minimum buffer time between a landing and the next take-off . Another important set of constraints are the flight restriction rules , which forbid certain aircraft to operate certain flights . There can be many reasons for the restriction - there can be a curfew for the arrival airport and some aircraft , because the aircraft violates noise or environmental restrictions . But there can also be more down-to-earth reasons , like the aircraft not having the required in-flight entertainment system or extra fuel tanks required for a long flight . Either way , the result is that an aircraft is restricted from operating a flight . Finally , there are the maintenance rules . Aviation authorities require that all aircraft undergo various types of maintenance activities regularly . There are many maintenance types , depending om aircraft type , registration country , and airline . Typically , the rules specify that aircraft must undergo maintenance every X hours , or every Y landings . Airlines often also require that their aircraft return to a maintenance base frequently , even if no maintenance is done , to increase robustness in case disruptions occur . These rules typically specify that aircraft must come back to a maintenance base every Z days . The normal representation of the Tail Assignment problem is in terms of a flight network . In the flight network , each node represents a flight , or some other activity such as a preassigned maintenance activity for specific aircraft , and each arc represents a connection between two flights or activities . For example , if operating flight f followed by flight f ' is allowed according to connection rules , the connection from f to f ' is considered legal , and the flight network will contain an arc between nodes f and f ' . Since we are solving a dated problem , where flights are fixed in time , there are carry-in activities in the beginning of the period representing the last flights operated by each aircraft in the previous planning period , and the network is acyclic . The goal is now to find paths -LRB- routes -RRB- through the network for all aircraft , starting at the carry-in activities , such that all flight nodes are covered exactly once , and all rules are satisfied .

Problem 115 (Tail Assignment) — Detection of the decisions and objects to be modeled

Tail Assignment is the problem of deciding which individual aircraft -LRB- identified by its tail number -RRB- should cover which flight . Each aircraft is thus assigned a route consisting of a sequence of flights , and possibly other activities such as maintenance , to perform . Tail Assignment deals with individual constraints , flights which are fixed in time , as well as individual rules for each tail . The planning period is typically one month . The purpose is to really create a solution that is possible to operate , satisfying all rules and regulations . The most basic rules are rules which only depend on two flights , so-called connection-based rules . For example , there must be a certain minimum buffer time between a landing and the next take-off . Another important set of constraints are the flight restriction rules , which forbid certain aircraft to operate certain flights . There can be many reasons for the restriction - there can be a curfew for the arrival airport and some aircraft , because the aircraft violates noise or environmental restrictions . But there can also be more down-to-earth reasons , like the aircraft not having the required in-flight entertainment system or extra fuel tanks required for a long flight . Either way , the result is that an aircraft is restricted from operating a flight . Finally , there are the maintenance rules . Aviation authorities require that all aircraft undergo various types of maintenance activities regularly . There are many maintenance types , depending om aircraft type , registration country , and airline . Typically , the rules specify that aircraft must undergo maintenance every X hours , or every Y landings . Airlines often also require that their aircraft return to a maintenance base frequently , even if no maintenance is done , to increase robustness in case disruptions occur . These rules typically specify that aircraft must come back to a maintenance base every Z days . The normal representation of the Tail Assignment problem is in terms of a flight network . In the flight network , each node represents a flight , or some other activity such as a preassigned maintenance activity for specific aircraft , and each arc represents a connection between two flights or activities . For example , if operating flight f followed by flight f ' is allowed according to connection rules , the connection from f to f ' is considered legal , and the flight network will contain an arc between nodes f and f ' . Since we are solving a dated problem , where flights are fixed in time , there are carry-in activities in the beginning of the period representing the last flights operated by each aircraft in the previous planning period , and the network is acyclic . The goal is now to find paths -LRB- routes -RRB- through the network for all aircraft , starting at the carry-in activities , such that all flight nodes are covered exactly once , and all rules are satisfied .

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