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DCT Analysis

DCT Analysis. Concepts:. UML-like class model of essential classes and actions. Conceptual model:. Simplest model: connected queues. More advanced models differ between 3 classes of trucks and various actions of crane. Essence: 2 connected queues. (only 8 exceptions out of 500).

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DCT Analysis

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  1. DCT Analysis

  2. Concepts: UML-like class model of essential classes and actions.

  3. Conceptual model: Simplest model: connected queues. More advanced models differ between 3 classes of trucks and various actions of crane.

  4. Essence: 2 connected queues. (only 8 exceptions out of 500) Most important parameters: rk (keeper occupation rate) rc (crane occupation rate) Assume M/D/1 queues (exp arrival, const processing) if rk ≥rc, then crane queue empty. If rk < rc, then average queue length keeper: C/(1-rk) average queue length crane+keeper: C/(1-rc) (approximately for some constant C) If e.g. rk= 0.9 and rc= 0.91, then keeper queue 10C and crane queue C. Greatest capacity problem with crane, though! c.f. Arena model DCT.doe in "examples" directory.

  5. Problem: large queues; keeper queue largest. Causes: keeper occupation rate too high, also crane capacity? Crane queue waiting time 35% of keeper waiting time, so crane capacity is an issue! Solutions: increase keeper productivity. Investigate crane occupation rate. Increase crane productivity also.

  6. Short-term temporary solution: increase working hours. Cost: extra payment to workers, which is manageable ("business is booming"). Benefits: less dissatisfaction of customers. Longer term solution for keeper problem: use IT! Crane solutions (in any combination): - faster crane - double queue - improve container storage

  7. Assignments • 4-5 assignments throughout the course • Bonus for exam: max. 2 points • Bonuses awarded for overall qualityand nice parts (e.g. concepts, problem analysis and suggestions). • This assignment:score ≥ 8: full bonus (.4)OK(7): small bonus (.2)

  8. Impression • Much enthousiasm and hard work. • Some reports were very good (talent or experience). Need course? • Others need not despair.Hopefully course will help you.

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