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Extending Temporal Databases to Deal with Telic/Atelic Medical Data Paolo Terenziani 1, Richard T. Snodgrass 2, Alessio Bottrighi 1, Mauro Torchio 3, Gianpaolo.

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Presentation on theme: "Extending Temporal Databases to Deal with Telic/Atelic Medical Data Paolo Terenziani 1, Richard T. Snodgrass 2, Alessio Bottrighi 1, Mauro Torchio 3, Gianpaolo."— Presentation transcript:

1 Extending Temporal Databases to Deal with Telic/Atelic Medical Data Paolo Terenziani 1, Richard T. Snodgrass 2, Alessio Bottrighi 1, Mauro Torchio 3, Gianpaolo Molino 3 1 DI, Univ. Piemonte Orientale A. Avogadro, Alessandria, Italy 2 Department of Computer Science, University of Arizona, Tucson, AZ, USA 3 Lab. Informatica Clinica, Az. Ospedaliera S. G. Battista, Torino, Italy - The problem: an example - The problem: a general perspective - Need for a general (not ad-hoc) solution - The solution (sketch) (see AIME and IEEE TKDE papers) - Conclusions

2 Introduction - Temporal information plays a basic role in Medical data - Need for suitable data models and query languages - Many approaches (mostly extensions/modifications of relational model) - Lack of specific supports makes the task of managing medical temporal data quite complex - All approaches share the same limitation: the underlying semantics is point-based, so that telic (medical) data connot be properly dealt with

3 The problem: an example John had two i.v. infusions of the drug Y, one starting at 10:00 and ending at 10:50, and the other from 10:51 to 11:30 (all extremes included) ; John had an i.v. of drug Z from 17:05 to 17:34, Mary had two i.v. infusions of Z, one from 10:40 to 10:55 and the other from 10:56 to 11:34, Ann had an i.v. from 10:53 to 11:32. Point-based semantics 10:00 10:01 ……

4 The problem: an example NOTICE (1): All approaches in the literature adopt point- based semantics, even if they adopt different representations Point-based semantics 10:00 10:01 …… 10:50, 10:51, e.g., TSQL2

5 The problem: an example Point-based semantics 10:00 10:01 …… 10:50, 10:51, Answers must be based on the semantics of data (and not on the representation!) Some pieces of information cannot be captured in any approach based on point based semantics!

6 The problem: an example UPWARD INHERITANCE (Q1)Who had one i.v. of Y lasting more than 1 hour? Answer: { } COUNTABILITY (Q3)How many i.v. did John have? Answer: 2

7 The problem: a general perspective Not only a problem in case of consecutive time intervals! PROJECTION e.g., Select Drug, VT from PHLEBO GRANULARITY CHANGES e.g., Scale up to hours

8 The problem: a general perspective Telic vs atelic facts Aristotle: Telic facts (countable, no upward inheritance, ……) (e.g., i.v. infusion) Atelic facts (not-countable, upward inheritance, …..) (e.g., patient X having a temperature > 38) Cognitive Science (e.g., [Bloom et al., 80]) … and, more recently, in AI Linguistics (e.g., [Bennet & Partee, 78]) NOTICE: Classical TDB approaches (and point-based semantics) perfectly cope with atelic facts!

9 Need for a general (not ad-hoc) solution Analogous to the question: why not just adding an additional attribute to relational tables to deal with validity times? … about 15 years of DBT reasearch responding to the second question! Basically: -time is a special status, and deeply impacts the semantics of the other attributes -thus, it needs a specialised treatment (e.g, definition of the temporal algebraic operators) - ad-hoc solutions are: difficult, likely to be erroneous, not economical, not compatible e.g., Why not just adding an additional (surrogate) attribute to keep all occurrences of telic tables separate?

10 Need for a general (not ad-hoc) solution A further problem: aktionsart coercions E.g., progressive forms coerce telic statements into atelic ones John had an i.v. infusions starting at 10:00 and ending at 10:50 John was having an i.v. infusions at 10:30 What is the impact on TDBs? In short: general problems need to be solved once-and-forall in a general (not ad-hoc) way Ex.1Who was having an i.v. while John was having an i.v.? Ex.2Who had a (complete) i.v. while having an i.v.?

11 Our solution: Point-based + Interval-based Semantics Interval-based semantics for telic facts (e.g., i.v. infusion) Coercion functions to switch from a interval to point semantics, and viceversa [10:00 – 10:50] [10:40 – 10:55] [10:51 – 11:30] …… Point-based semantics for atelic facts (e.g., temperature > 38) 10:00 10:01 10:02, ……

12 Our solution: Data model: telic + atelic tables Telic tables for telic facts (e.g., i.v. infusion) Atelic tables for atelic facts (e.g., temperature > 38) Also non-temporal (snapshot) tables

13 Our solution: Three-sorted algebra Telic algebraic operators Atelic algebraic operators Non-temporal (snapshot) operators Coercion functions [Terenziani & Snodgrass, 04] IEEE Transactions on Knowledge and Data Engineering, 16(4), , April 2004.

14 Our solution: Query language Extension to TSQL2: AIME05 paper Limited extensions to the language are sufficient (substantial extensions in the semantics) TELIC SELECT P2.P_CODE FROM T_PHLEBO (ATELIC PERIOD) AS P, T_PHLEBO (PERIOD) AS P2 WHERE P.P_CODE='John' AND P.Drug=' Y ' AND P CONTAINS P2 Ex. Who had one (complete) i.v., while John was having an Y i.v.?

15 Our solution: Query language Principled and general solution, and increased expressiveness without much user effort (only limited extensions to the query language)! TELIC SELECT P2.P_CODE FROM T_PHLEBO (ATELIC PERIOD) AS P, T_PHLEBO (PERIOD) AS P2 WHERE P.P_CODE='John' AND P.Drug=' Y ' AND P CONTAINS P2 T_PHLEBO ATELIC(T_PHLEBO) P P.P_CODE=John, … P CONTAINS R1 TELIC P2


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