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The Doctor Rostering Problem - Asser Fahrenholz

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Chapter 2. <strong>The</strong> <strong>Doctor</strong> <strong>Rostering</strong> <strong>Problem</strong> 5<br />

<strong>Doctor</strong> 1 2 3 4 5 6<br />

Week 1 Tuesday NDO Wednesday Thursday Friday Monday<br />

Week 2 NDO Wednesday Thursday Friday Monday Tuesday<br />

Week 3 Wednesday Thursday Friday Monday Tuesday NDO<br />

Week 4 Thursdag Friday Monday Tirsdag NDO Wednesday<br />

Week 5 Friday Monday Tirsdag NDO Wednesday Thursdag<br />

Week 6 Monday Tirsdag NDO Wednesday Thursdag Friday<br />

Table 2.1: Rolling days off, NDO: no day off<br />

2.2 Rolling Days Off<br />

A specific requirement of this project is rolling days off (RDO). <strong>The</strong>se define which<br />

weeks a doctor gets a day off and which weeks contains no day off (NDO) for each<br />

doctor. Table 2.1 illustrates the concept of rolling days off.<br />

A key point of RDO is the fact that all doctors receive weekends where they have both<br />

the predating Friday and the postdating Monday off.<br />

<strong>The</strong> RDO as a constraint is omitted from the mathematical model of this problem and<br />

is instead implemented as a program mechanism.<br />

2.3 Literature review<br />

Previous work on the nurse scheduling problem (NSP) has been covered by many ap-<br />

proaches, taking different angles and perspectives throughout the problem environment.<br />

In this section, I briefly review articles that has served as inspiration to this project.<br />

Nonobe and Ibaraki [18] applies a general weighted constraint satisfaction problem<br />

(WCSP) solver, using a Tabu Search (TS), to a range of problems, incl. the NSP.<br />

Also applying a weight control mechanism to each iteration of TS works well for them.<br />

<strong>The</strong>y choose to handle hard and soft constraints on the same level of processing.<br />

Dias et al. [7] deals with a relatively large problem. <strong>The</strong>y apply both a Genetic Algorithm<br />

(GA) heuristic and a TS for solving a problem with over 1500 nurses, 30 supervisory<br />

nurses and 30 wards and finds that the two heuristics performs equally well, with one<br />

more time efficient and slightly worse results than the other and vice versa.<br />

In Bard and Purnomo [2] the authors discuss the issue of sudden shortages appearing due<br />

to the fluctuation in patients needing health care. <strong>The</strong> problems handled are relatively<br />

large, scheduling more than 120 nurses.

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