http://2016.semantics.cc/jind%C5%99ich-mynarz

1. DB-quiz
a DBpedia-backed knowledge game
Jindrich Mynarz, Václav Zeman
— University of Economics, Prague
SEMANTiCS 2016, September 12–15,
2016, Leipzig, Germany

2. Game mechanics
→ Play at http://mynarz.net/db-quiz
DB-quiz is a knowledge-based game inspired by the Czech
TV show AZ-kvíz.
Win board fields by guessing entity’s name based on its
abbreviation and description. The player who connects all
sides of the triangular game board wins.

3. Game mechanics

4. Data
Game questions are automatically generated from Czech
or English DBpedia.
Domains of questions are partitioned by rdf:type (such
as persons or films) or by dcterms:subject (such as
members of the Communist party).
Alternatively, questions can be sourced from a Google
Spreadsheet.

5. Implementation
A single-page application developed in Clojurescript
backed by a SPARQL endpoint with pre-processed data
from DBpedia.
Currently, it lacks a multiplayer mode, so that players
need to take turns playing in the same browser.
Source code at https://github.com/jindrichmynarz/db-quiz.
Live demo at http://mynarz.net/ db-quiz.

6. Problems addressed
1.
How to estimate difficulty
of questions
automatically?
2.
How to clean questions
from spoilers that give
away the answers?

7. Estimating difficulty of questions
We used indegree (= number of inbound links via
dbo:wikiPageWikiLink to the question’s answer) as a
proxy to difficulty.
We split the area under the
curve of indegree distribution
in a question’s domain into
thirds that correspond to 3
game difficulties: easy,
normal, and hard.

8. Removing spoilers from questions
We use the answer’s surface forms from anchor texts of
inbound links (dbo:wikiPageWikiLinkText) or name-like
properties (such as dcterms:title or dbo:birthName).
This way we obtain variant spellings, declinations, or
aliases of the answer.
Each surface form found in the question is replaced by the
answer’s abbreviation.

9. Evaluation
We tested the game via online user testing.
6 months worth of Google Analytics data (1401 visits from
892 users, 3514 answers for 2315 questions, 242 spoiler
reports, and 138 finished game sessions).
Tracked events:
● Answer correctness: + derived answer success rate
● Spoiler reports: A/B testing with/without spoilers
removed

10. Evaluation results
Spoilers reported approximately 4.5× more for questions
without spoilers removed.
Aggregated answer
success rates:
We tested the correlation of the averaged answer success
rates with indegrees and the numbers of page views.

11. Evaluation results
Indegree has a weak to moderate positive correlation with
answer success rate. However, number of page views has
a stronger correlation.

12. Future work
● Use page views for estimating
difficulty.
● Add yes/no questions for the
missed fields.
● Implement a multiplayer mode.
→ Play at http://mynarz.net/db-quiz