Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
© Fraunhofer IGD
SEMANTICS VISUALIZATION FOR FOSTERING SEARCH RESULT COMPREHENSION
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Christian Stab Fraunhofer-Institute for Computer Graphics Research IGD Fraunhoferstraße 5 64283 Darmstadt - Germany Tel +49 6151 155 – 557 | Fax – 139 [email protected] www.igd.fraunhofer.de
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Introduction
• Visualizing Search Results in Semantic Domains
• Application Scenario
• Evaluation
• Future Work & Conclusion
OVERVIEW
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Optimal use of data plays a major role
• global competition & competitiveness of industrial companies
• Semantic technologies provide adequate tools for improving data handling
• e.g. linking heterogeneous data, generating broader context, facilitating information access, …
• … and are adopted in daily search processes
• Usually, search results are presented in sorted and mainly textual lists
• Semantic information remains in most cases hidden from the user, though this information supports users in information seeking tasks
INTRODUCTION
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Novel approach that utilizes information visualization and semantic information
• Support for relevance assessment
• Offers more transparency in the search result generation
• Visualization of Query-Result-Relations
• fine-grained visual overview of search result relevancies
• Visual feedback for query-enhancement
• Allows users to narrow search results and to refine individual search processes
INTRODUCTION
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Visualization approach is part of the SemaVis-Framework
• adaptable visualization framework for semantics
• contains different and aspect oriented visualization techniques (e.g. geo, time,…)
• used in several application scenarios and use cases
• Presented visualization approach is based and a force-based layout algorithm
• places nodes in a two-dimensional space by assigning different forces to the edges and nodes of the graph
• these forces are adapted in an iterative simulation until a mechanical equilibrium is reached
• Approach uses a weighted model based on similarities emerged during the semantic retrieval process
VISUALIZING SEMANTIC SEARCH RESULTS
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
www.semavis.net
© Fraunhofer IGD
Two different node types:
Attribute Nodes
• are placed in a circular form during the initialization of the visualization
• users can freely move them on the surface
Result Nodes
• represent the results of the search
• are suspended between the attribute nodes
• Positioned by the force-layout algorithm according to their similarities and relations to attribute nodes
VISUALIZING SEMANTIC SEARCH RESULTS
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Each query term is represented in an attribute node
• Semantic meaning is shown in the node label for unambiguous assessment of the results
• Relations between results and query terms are visualized with directed edges
• User are able to unambiguously determine most relevant results
VISUALIZING SEMANTIC SEARCH RESULTS Query-Result-Relations
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Search results can be found by considering semantic structures
• e.g. query terms match only to semantically related resources
• To enable users to comprehend why specific results are considered as relevant adequate feedback about the reasons of result generation is needed
• In other words: Resources that are responsible for result retrieval should also be visible to the user
• Solution: Expandable Attribute Nodes
• contains resources from the semantic neighborhood that are of some relevance for result generation
• labels of these expandable attribute nodes are derived from the conjoint concept in the semantic structure
VISUALIZING SEMANTIC SEARCH RESULTS Semantic neighborhood and hierarchical attributes
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
VISUALIZING SEMANTIC SEARCH RESULTS Semantic neighborhood and hierarchical attributes
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
For improving the visualization different similarity values are utilized and mapped to visual properties (e.g. length, color, size, …)
Partial S imilarities
• A measure between attributes nodes and results
• Represent the relevance of a retrieved resource to a given query term
• adapt the weights of edges between results and attribute nodes
Result S imilarities
• aggregated values of all partial similarities
• Correspond to the overall relevance of a retrieved result
• mapped to size and color of result nodes
VISUALIZING SEMANTIC SEARCH RESULTS Mapping results’ relevance to visual properties
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Common search strategy includes to reformulate or to enhance the query
• Transferred to the presented visualization approach this corresponds to substitutions or reassignments of attribute nodes
• instantiation of additional attributes defines a more specific search condition
• removal of attribute values results in wider-ranged and less specific search spaces
• Un-instantiated attributes are recommended by the visualization
• these are retrieved by attributes of the current result set
• are visualized as additional attributes
• The effect of changing the search condition is immediately visible
• the representation of query-result-relations reveals which of the current results fulfills new conditions.
VISUALIZING SEMANTIC SEARCH RESULTS Visual feedback for query enhancement
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
VISUALIZING SEMANTIC SEARCH RESULTS Visual feedback for query enhancement
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• The visualization approach is applied in the field of mechanical engineering
• highly complex processes (from initial development over construction to production steps and consumer services)
• diverse user groups
• Same resource is treated in different context
• Semantic technologies are used to link different knowledge bases and to provide a novel way to access information
• Objective of the presented visualization:
• provide homogeneous access to a combined knowledge base
• providing more transparency in the search processing
• enable users to unambiguously assess the results of individual search processes
• demonstrator is available at http://athena.igd.fraunhofer.de/Processus/semavis.html
APPLICATION SCENARIO
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Comparison of the visualization with a common list presentation
• Goal of the evaluation is to answer questions like
• Is the user really supported in assessing search results?
• Satisfies our approach the needs of users?
• H1: There is a difference in task completion time between the list representation and the visualization in assessing search results
• Additionally we measured the user satisfaction as a subjective evaluation criteria
EVALUATION
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Basic within-group design
• Each participant accomplishes the given tasks in each condition (list presentation and visualization)
• Possible learn-effects when switching between conditions are controlled by
• systematic randomization of condition- and task-ordering
• advising participants to disregard knowledge from previous conditions and explicitly showing the solutions
• Three tasks; accomplished from each participant in each condition
• Pre-assigned queries to ensure that each participant retrieves the same visual representation
• Task 1: Identify relations between each search result and the terms of the given query
• Task 2: Similar to task 1 but with hierarchical structured attributes in the result set
• Task 3: Identify most relevant item for a specific search situation
• Time limit for each task: 3 Minutes
• Wrong answers were also estimated with 3 minutes
EVALUATION Experimental Design
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• 17 participants attended the evaluation
• mainly graduates and students
• average age 24 - 29 years
• participants were mainly involved in computer science (M = 4.65; SD = 0.6)1
• no previous knowledge of the engineering domain
• Procedure for each participant
• 1. General Introduction
• 2. Brief introduction to both systems
• 3. Task completion; after each task satisfaction ranking and five additional questions concerning the subjective opinion
• 4. brief demographic questionnaire
1 measured on a five point Likert scale (5 = very much experience; 1 = very little experience) in the demographic part of the questionnaire
EVALUATION Procedure
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Participants performed better with the visualization
• List Presentation: avg(t) = 88.1 sec; SD = 30.1
• Visualization: avg(t) = 51.3 sec; SD = 25.8
• Significant difference in task completion times (t(50) = 7.8028; p<0.05)
• User Satisfaction ratings2
• List Presentation: 5.31; SD = 1.91
• Visualization: 7.57; SD = 1.1
• Participants prefer the visualization 3
• Question: “Would you use the system in the future for similar searching tasks?”
• List Presentation: 3.24; SD = 0.87
• Visualization: 4.25; SD = 0.77
2 Measured on a scale from 1 - 9 after each task
3 Measured on a five-point Likert scale
EVALUATION Results
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
EVALUATION Results
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Transfer to other domains
• Visualization was applied in the field of mechanical engineering
• in this domain data diversity, user roles and processes are controllable
• data access methods can be accurately aligned to specific tasks
• further investigations are needed to prove if the proposed approach is also transferable to other domains
• User acceptance
• most search user interfaces are based on result list presentations
• cause of the public’s great familiarity there is a certain degree of risk with the introduction of novel technologies
• even if novel approaches provide a variety of extended features and easier information access it is not sure if user accept a novel technology
DISCUSSION
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
• Novel approach for search result visualization that utilizes semantics
• Successfully fosters search result comprehension
• Supports users in assessing retrieved resources
• Imparts different semantic interpretations of query terms
• Visual feedback for query enhancement fosters common search strategies and offers more transparency in search result processing
• Future Work
• Extension of query refinement feature: removal / change and multiple instantiation of attribute nodes
• Integration and transfer to other domains
CONCLUSION & FUTURE WORK
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, 31.05.2012 – Christian Stab
© Fraunhofer IGD
THANK YOU FOR LISTENING
IGD
_Fo
lien
vorl
ag
e_v
2010.1
0.p
pt
Christian Stab Fraunhofer-Institute for Computer Graphics Research Fraunhoferstraße 5 64283 Darmstadt - Germany Tel +49 6151 155 – 557 | Fax – 139 [email protected] www.igd.fraunhofer.de
Semantics Visualization for Fostering Search Result Comprehension – ESWC 2012, dd.05.2012 – Christian Stab
Questions?