10. What is a “Task”?
Online credit
check
Mortgage
in principle
Facebook House buying
guide
Quit smoking
benefits
Solicitors
near me
…
Houses
for sale
Loans for
house
…
10:00am 10:03am 10:07am 12:30pm
17:00pm 17:02pm 17:06pm 18:15pm
Session 1 Session 2
Session 3 Session 4
A task is an atomic information need resulting in one or more queries [Jones and Klinkner, CIKM 2008]
22. Latent Dirichlet Allocation [Blei et al, JMLR’03]
• LDA is a generative probabilistic model of a corpus. The basic idea
is that the documents are represented as random mixtures over
latent topics, where a topic is characterized by a distribution over
words.
26. • Cjk : click counts associating node j to k
• Define transition probabilities Pt+1|t (kij) from j to k:
• s is the self-transition probability, which corresponds to
the user favoring the current query or document
Random Walks on Click Graph [Craswell et al., SIGIR’07]
28. Section 2: Characterizing Tasks
• Understanding Intents & Tasks
– Query intents in IR
– Search sessions
– Sessions à Tasks
• Characterizing Tasks across devices
– Desktop based search
• Taxonomy of browsing & querying behavior
– Intelligent Assistants
• Digital Assistants
– Use cases
– User engagement
• Voice-only Assistants
– Use cases
– User engagement
29. Search Sessions as Tasks
Online credit
check
Mortgage
in principle
Facebook House buying
guide
Quit smoking
benefits
Solicitors
near me
…
Houses
for sale
Loans for
house
…
10:00am 10:03am 10:07am 12:30pm
17:00pm 17:02pm 17:06pm 18:15pm
Session 1 Session 2
Session 3 Session 4
Session continuation detection [Jon08, Agi12]
Session based task extraction [Luc11, Hua13, Wan13, Awa14, Luc13]
A Session is a chronologically ordered sequence of user interactions with the
search engine resulting in one or more queries – aimed at solving a single
information need.
47. Common Use-Case Scenarios
• General search
• Commands
– Alarms, camera, system
settings
• Answers
– Find instant answers
• MyStuff
– Search local files &
folders
0 0.1 0.2 0.3 0.4 0.5
MyStuff
Answers
Commands
GeneralSearch
Percentage Interactions
Cortana Desktop Use-cases
[Mehrotra et al., CAIR 2017]
48. Common Use-Case Scenarios
Spread across session length
• MyStuff
– Over 70% single query sessions
originate from MyStuff
– Proportion on MyStuff steadily
decreases as the session length
increases
• Instant Answers
– Increasing proportion of
sessions with session length
• Steady proportions of General
Search & Commands
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Use-case Mix-Up in Sessions
MyStuff Answers
CommandControl GeneralSearch
[Mehrotra et al., CAIR 2017]
49. Beyond Traditional IR
Commands Answers
0 0.1 0.2 0.3 0.4 0.5
Open App
Weather
How To
BilingualDict
Math
News Answers
Time zone
Entity Lookup
Percentage Interactions
Beyond Chitchat & General Search
• Top Commands: reminders, alarms, music
• Users seek direct answers: weather, HowTos, Math etc
• Envision appropriate changes as system evolves
[Mehrotra et al., CAIR 2017]
58. Summary: Characterizing Tasks
• Understanding User Intents & Tasks
– Different abstractions of understanding user needs: Queries à Sessions à Tasks
– Methods for intent identification
• Classification
• Clustering
– Search sessions and Tasks
• Multitasking sessions
• Tasks provide a better abstraction
• Characterizing Tasks
– Taxonomy of web search tasks
– Traditional desktop based search tasks are different than emerging tasks on smart
assistants
– User interactions differ across different devices
– More contextual information available for smart assistants