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SUMMARY:Hands-on 3: semantic search\, BM25/hybrid retrieval and reranking
DTSTART;VALUE=DATE-TIME:20260707T103000Z
DTEND;VALUE=DATE-TIME:20260707T105500Z
DTSTAMP;VALUE=DATE-TIME:20260703T161444Z
UID:indico-contribution-1153@events.grnet.gr
DESCRIPTION:Speakers: Sotiris  Gyftopoulos (ATHENA RC)\nThis third hands-o
 n tutorial lets participants compare retrieval strategies directly in the 
 Colab notebook. Using representative Greek-language public-service questio
 ns\, participants will run semantic search\, keyword-based search and hybr
 id retrieval over the same indexed dataset. They will inspect returned chu
 nks\, compare ranking behaviour and identify cases where one retrieval str
 ategy succeeds while another misses important evidence. The session also i
 ntroduces practical analysis of false positives\, missing evidence and noi
 sy context. Participants will apply reranking to candidate chunks and comp
 are the Top-K context before and after reranking\, observing how ordering 
 affects the evidence available to the generator. The tutorial encourages p
 articipants not to trust retrieval scores blindly\, but to read and evalua
 te the retrieved passages. By the end\, participants will understand how t
 o choose retrieval strategies for different query types and how to diagnos
 e retrieval weaknesses systematically. These observations support later gr
 ounding\, citation checking and end-to-end answer evaluation activities in
  the notebook.\n\nhttps://events.grnet.gr/event/213/contributions/1153/
LOCATION:
URL:https://events.grnet.gr/event/213/contributions/1153/
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