Current Students
PhD Students
Hilal Tarakçı Multimedia and semantic
web
Ali Anıl Sınacı
Tolga Can
MS Students
Gizem Öztürk Personalization in multimedia
retrieval
Çağla Yaman Ontology-based Personalization
in video databases
Müjdat Bayar Video
Analysis for event detection
Esra Abacıoğlu Automatic object recognition in videos
Goncagül Demirdizen Ontology-based multimedia database systems
Gökhan Yaprakkaya Automatic Face Rcognition in videos
Former Students
1. Yakup Yildirim Formalizing
Workflows Using the Event Calculus, 2000
Abstract:
The
event calculus is a logic programming formalism for representing events and
their effects especially in database applications. This thesis presents the use
of the event calculus for specifying and simulating workflows. The proposed
framework maintains a representation of the dynamic world being modeled on the
basis of user supplied axioms about preconditions and effects of events and the
initial state of the world. The net effect is that a workflow specification can
be made at a higher
level of abstraction. Within this framework it is possible to
model sequential and concurrent activities with synchronization when necessary.
It is also possible to model agent assignment and concurrent workflow
instances. A logic programming approach to the computational problem is
adopted.
2. Mesru Koprulu Spatio-temporal querying in video databases, 2001
In
this thesis a video data model that allows efficient and effective
representation and querying of spatio-temporal
properties of objects is presented. The data model is focused on the semantic
content of video streams. Objects, events, activities performed by objects are
main interests of the model. The model supports fuzzy spatial queries including
querying spatial relationships between objects and querying the trajectories of
objects. The model is flexible enough to define new spatial relationship types
between objects without changing the basic data model. A prototype of the
proposed model has been implemented. The prototype allows various spatio-temporal queries along with the fuzzy ones and it is
prone to implement compound queries without major changes in the data model.
3. Esen Kacar Mining
Fuzzy Spatial Association Rules, 2001
Abstract:
Discovering
interesting, implicit knowledge and general relationships in geographic
information databases is very important to understand and to use these spatial
data. One of the methods for discovering this implicit knowledge is mining
spatial association rules. A spatial association rule is a rule indicating
certain association relationships among a set of spatial and possibly
non-spatial predicates. In the mining process, data is organized in a
hierarchical manner. However, in real-world applications it may not be possible
to construct a crisp structure for this data, rather
some fuzzy structures should be used. Fuzziness, i.e. partial belonging of an
item to more than one sub-item in the hierarchy, could be applied to the data
itself, and also to the hierarchy of spatial relations. This thesis shows that,
strong association rules can be mined from large spatial databases using fuzzy
concept and spatial relation hierarchies.
4. Narin Emeksiz Diagnosis
of Gastric Carcinoma Tumours by Multi Class Voting,
2001
5. Deniz Canturk Time-based
workflow mining, 2005
Abstract:
Creating
a workflow design is a complicated process and usually there are differences
between the actual workflow processes and the processes as seen by the
designer. Therefore, new data mining techniques for (re)discovering workflow
models have been proposed. Starting point for such techniques are so-called
“workflow logs" which contains information about the workflow
process as it is actually being executed. In this paper, a new workflow mining
technique based on time information is proposed. It is assumed that events in
workflow logs are recorded with their start and end timestamps. This
information is used in order to determine task orders and control flows between
tasks. This new algorithm can be used to mine workflow graphs which contain
basic workflow structures, such as sequential, parallel, iterative routings and
or-join. The proposed algorithm finds a concrete workflow model as an output.
In this workflow model execution durations of tasks and waiting times between
tasks are included; hence the start time of each task and total execution time
of the workflow can be discovered. This information could also be used in
commenting on hidden tasks.
6. Guzen Erozel Natural
Language Interface on a video data model, 2005
Abstract:
The
video databases and retrieval of data from these databases have become popular
in various business areas of work with the improvements in technology. As a
kind of video database, video archive systems need user-friendly interfaces to
retrieve video frames. In this thesis, an NLP based user interface to a video
database system is developed using a content-based spatio-temporal video data
model. The data model is focused on the semantic content which includes
objects, activities, and spatial properties of objects. Spatio-temporal
relationships between video objects and also trajectories of moving objects can
be queried with this data model. In this video database system, NL interface
enables flexible querying. The queries, which are given as English sentences,
are parsed using Link Parser. Not only exact matches but similar objects and
activities are also returned from the database with the help of the conceptual
ontology module to return all related frames to the user. This module is
implemented using a distance-based method of semantic similarity search on the
semantic domain-independent ontology, WordNet. The semantic representations of
the given queries are extracted from their syntactic structures using
information extraction techniques. The extracted semantic representations are
used to call the related parts of the underlying spatio-temporal video data model
to calculate the results of the queries.
7. Onur Aydin Automated
web service composition with event calculus, 2005
Abstract:
As
the Web Services proliferate and complicate it is becoming an overwhelming job
to manually prepare the Web Service Compositions which describe the
communication and integration between Web Services. This thesis analyzes the
usage of Event Calculus, which is one of the logical action-effect definition
languages, for the automated preparation and execution of Web Service Compositions.
In this context, planning capabilities of Event Calculus are utilized.
Translations from Planning Domain Description Language and DARPA Agent Markup
Language to Event Calculus are provided to show that Web Services can be
composed with the help of Event Calculus. Also comparisons between Event
Calculus and other planning languages used for the same purposes are presented.
8. Cigdem Celik An
MPEG-7 Video Database System for
content-basedf management and retrieval, 2005
Abstract:
A video
data model that allows efficient and effective representation and querying of spatio-temporal properties of objects has been previously
developed. The data model is focused on the semantic content of video streams.
Objects, events, activities performed by objects are the main interests of the
model. The model supports fuzzy spatial queries including querying spatial
relationships between objects and querying the trajectories of objects. In this
thesis, this work is used as a basis for the development of an XML-based video
database system. This system is aimed to be compliant with the MPEG-7
Multimedia Description Schemes in order to obey a universal standard. The
system is implemented using a native XML database management system. Query
entrance facilities are enhanced via integrating an NLP interface.
9. Funda Karagoz Application
of Schema Matching Methods to Semantic Web Service Discovery, 2006
Abstract:
The Web turns out to be a collection of services
that interoperate through the Internet. As the number of services increase, it
is getting more and more diffucult for users to find, filter and integrate
these services depending on their requirements. Automatic techniques are being
developed to fulfill these tasks. The first step toward automatic composition
is the discovery of services needed. UDDI which is one of the accepted web
standards, provides a registry of web services. However representation
capabilities of UDDI are insufficient to search for services on the basis of
what they provide. Semantic web initiatives like OWL and OWL-S are promising
for locating exact services based on their capabilities. In this thesis, a new
semantic service discovery mechanism is implemented based on OWL-S service
profiles. The service profiles of an advertisement and a request are matched
based on OWL ontologies describing them. In contrast to previous work on the
subject, the ontologies of the advertisement and the request are not assumed to
be same. In case they are different, schema matching algorithms are applied.
Schema matching algorithms find the mappings between the given schema models. A
hybrid combination of semantic, syntactic and structural schema matching
algorithms are applied to match ontologies.
10. Huseyin Yilmaz Realizing the specification and execution of
workflows through event calculus, 2006
Abstract:
Workflow
management promises a solution to an age-old problem: controlling, monitoring,
optimizing and supporting business processes. What is new about workflow
management is the explicit representation of the business process logic which
allows for computerized support. In the light of this support, many researchers
developed different approaches to model new systems with different capabilities
to solve this age-old problem. One of the approaches is using logic-based
methodology for the specification and execution of workflows. Here, the event
calculus, a logic programming formalism for representing events and their
effects especially in database applications, is used for this approach. It is shown
that the control flow graph of a workflow specification can be expressed as a
set of logical formulas and the event calculus can be used to specify the role
of a workflow manager through a set of rules for the execution dependencies of
activities. Constructed workflow formalization through Event Calculus is
realized by using recent technologies, and the resulting product is named as EventFlow, including some administrative interfaces to
manage system and workflow engine. The architecture and implementation details
of EventFlow, an editor developed for graphical
representation of control flow graph, and used technologies are described. And
an example application is built to show the usability and execution of the
implemented system.
11.
Esra Kırcı Automatic
Composition of Semantic Web Services with the Abductive Event Calculus, 2007
Abstract:
This
thesis investigates the application of AI planning techniques to the web
service composition problem and in particular, it proposes the use of the
abductive event calculus in this domain. Web service compositions are defined
as templates using OWL-S ("OWL for Services"). These generic
composition definitions are converted to Prolog language as axioms for the
abductive event calculus planner and solutions found by the planner constitute
the specific result plans for the generic composition plan. In this thesis it
is shown that abductive planning capabilities of the event calculus can be used
to generate the web service composition plans that realize the generic procedure.
12.
Esat Kaan Kuban Abductive Planning Approach
for Automated Web Service Composition using only User Specified Inputs and
Outputs, 2008
Abstract:
Automated
web service composition can be achieved either by generating the composition
plan dynamically using given inputs and outputs, or by locating the correct
services if an abstract process model
is given.
This thesis investigates the former method which is dynamicly
generating the composition by using the abductive planning capabilities of the
Event Calculus. Event calculus axioms in Prolog language,
are generated using the available OWL-S web service descriptions in the service
repository, values given to selected inputs from ontologies
used by those semantic web services and desired output types selected again
from the ontologies. Abductive Theorem Prover which
is the AI planner used in this thesis, generates composition plans and
execution results according to the generated event calculus axioms.
13.
Özkan Göktürk METADATA
EXTRACTION FROM TEXT IN SOCCER DOMAIN, 2008
Abstract:
In
this thesis, we present an approach of metadata extraction from match reports
for soccer domain. The UEFA Cup and UEFA Champions League Match Reports are downloaded
from the web site of UEFA by a web-crawler. These match reports are
preprocessed by using regular expressions and then important events are
extracted by using hand-written rules. In addition to hand-written rules, two different
machine learning techniques are applied on match corpus to learn event patterns
and automatically extract match events. Extracted events are saved in an MPEG-7
file. A user interface is implemented to query the events in the MPEG-7 match
corpus and view the corresponding video segments.
14.
Hilal Tarakçı AN ONTOLOGY-BASED MULTIMEDIA INFORMATION
MANAGEMENT SYSTEM, 2008
Abstract:
In
this thesis, MPEG-7 ontology is used on top and the given user-defined ontologies are attached to the MPEG-7 ontology via a user
friendly interface, thus building MPEG-7 based ontologies
automatically. Our proposed system is an ontology-based multimedia information
management framework due to its modular architecture, ease of integrating with
domain specific ontologies naturally and automatic harmonization
of MPEG-7 ontology and domain-specific ontologies.
Integration with domain specific ontologies is
carried out by enabling import of domain ontologies
via a user-friendly interface which makes the system independent of application
domains.
15.
Mehmet Kuzu AUTOMATIC
WEB SERVICE COMPOSITION WITH AI PLANNING, 2009
Abstract:
In
this thesis, some novel ideas are presented for solving automated web service
composition problem. Some possible real world problems such as partial observability of environment, nondeterministic effects of
web services, service execution failures are solved through some mechanisms. In
addition to automated web service composition, automated web service invocation
task is handled in this thesis by using reflection mechanism. The proposed
approach is based on AI planning. Web service composition problem is translated
to AI planning problem and a novel AI planner namely “Simplanner”
that is designed for working in highly dynamic environments under time
constraints is adapted to the proposed system. World altering service calls are
done by conforming to the WS-Coordination and WS-Business Activity web service
transaction specifications in order to physically repair failure situations and
prevent undesired side effects of aborted web service composition efforts.
16. Onur Özorhan A
Service Oriented Peer to Peer Web Service Discovery Mechanism With Categorization
Abstract:
This thesis, studies automated methods to achieve web service advertisement
and discovery, and presents efficient search and matching techniques based on
OWL-S. In the proposed system, the service discovery and matchmaking is
performed via a centralized peer-to-peer web service repository. The repository
has the ability to run on a software cloud, which improves the availability and
scalability of the service discovery. The service advertisement is done
semi-automatically on the client side, with an automatic WSDL to OWL-S
conversion, and manual service description annotation. An OWL-S based unified
ontology -Suggested Upper Merged Ontology is used during annotation, to enhance
semantic matching abilities of the system. The service advertisement and
availability are continuously monitored on the client side to improve the
accuracy of the query results. User-agents generate query specification using
the system ontology, to provide semantic unification between the client and the
system during service discovery. Query matching is performed via complex
Hilbert Spaces composed of conceptual planes and categorical similarities for
each web service. User preferences following the service queries are monitored and
used to improve the service match scores in the long run.
17. Çağla Okutan A
Monolithic Approach to Automated Composition of Semantic Web Services with the
Event Calculus
Abstract:
In this thesis, a web service composition and
execution framework is presented for semantically annotated web services. A
monolithic approach to automated web service composition and execution problem
is chosen, which provides some benefits by separating the composition and
execution phases. An AI planning method using a logical formalism called Event Calculus
is chosen for the composition phase. This formalism allows one to generate a
narrative of actions and temporal orderings using abductive planning techniques
given a goal. Functional properties of services, namely
input/output/precondition/effects(IOPE) are taken into consideration in the
composition phase and non-functional properties, namely quality of service
(QoS) parameters are used in selecting the most appropriate solution to be
executed. The repository of OWL-S semanticWeb services are translated to Event
Calculus axioms and the resulting plans found by the Abductive Event Calculus
Planner are converted to graphs. These graphs can be sorted according to a
score calculated using the defined quality of service parameters of the atomic
services in the composition to determine the optimal solution. The selected
graph is converted to an OWL-S file which is executed consequently.
18. Atakan Şimşek Ontology-Based Spatio-Temporal
Video Management System
Abstract:
In this thesis, a system, called Ontology-Based
Spatio-Temporal Video Management System (OntoVMS) is developed in order to
supply a framework which can be used for semantic data modeling and querying in
video files. OntoVMS supports semantic data modeling which can be divided into
concept modeling, spatio-temporal relation and trajectory data modeling. The
system uses Rhizomik MPEG-7 Ontology as the core ontology. Moreover ontology expression
capability is extended by automatically attaching domain ontologies. OntoVMS supports
querying of all spatial relations such as directional relations (north, south
...), mixed directional relations (northeast, southwest ...), distance
relations (near, far), positional relations (above, below ...) and topological
relations (inside, touch ...); temporal relations such as starts, equal,
precedes; and trajectories of objects of interest. In order to enhance querying
capability, compound queries are added to the framework so that the user can
combine simple
queries by using “(”, “)”,
“AND” and “OR” operators. Finally, the use of the
system is demonstrated with a semi-automatic face annotation tool.
19. Mennan Güder Data Mining Methods
For Clustering Power Quality Data Collected Via Monitoring Systems Installed On
The Electricity Network
Abstract:
Increasing power demand and wide use of high
technology power electronic devices result in need for power quality
monitoring. The quality of electric power in both transmission and distribution
systems should be analyzed in order to sustain power system reliability and
continuity. This analysis is possible by examination of data collected by power
quality monitoring systems. In order to define the characteristics of the power
system and reveal the relations between the power quality events, huge amount
of data should be processed. In this thesis, clustering methods for power quality
events are developed using exclusive and overlapping clustering models. The methods
are designed to cluster huge amount of power quality data which is obtained from
the online monitoring of the Turkish Electricity Transmission System. The main
issues considered in the design of the clustering methods are the amount of the
data, efficiency of the designed algorithm and queries that should be supplied
to the domain experts. This research work is fully supported by the Public
Research grant Committee (KAMAG) of TUBITAK within the scope of National Power
quality Project (105G129).
20. Kezban Demirtaş Automatic Video Categorization And Summarizatıon
Abstract:
In this thesis, we make automatic video
categorization and summarization by using subtitles of videos. We propose two
methods for video categorization. The first method makes unsupervised categorization
by applying natural language processing techniques on video subtitles and uses
the WordNet lexical database and WordNet domains. The method starts with text
preprocessing. Then a keyword
extraction algorithm and a word sense disambiguation method are applied. The
WordNet domains that correspond to the correct senses of keywords are
extracted. Video is assigned a category label based on the extracted domains.
The second method has the same steps for extracting WordNet domains of video
but makes categorization by using a learning module. Experiments with documentary
videos give promising results in discovering the correct categories of videos. Video
summarization algorithms present condensed versions of a full length video by
identifying the most significant parts of the video. We propose a video
summarization method using the subtitles of videos and text summarization
techniques. We identify significant sentences in the subtitles of a video by
using text summarization techniques and then we compose a video summary by
finding the video parts corresponding to these summary sentences.
21. Erkin Eryol Probabilistic
Latent Semantic Analysis Based Framework For Hybrid Social Recommender Systems
Abstract:
Today, there are user annotated internet sites,
user interaction logs, online user communities which are valuable sources of
information concerning the personalized recommendation problem. In the
literature, hybrid social recommender systems have been proposed to reduce the
sparsity of the usage data by integrating the user related information sources
together. In this thesis, a method based on probabilistic latent semantic
analysis is used as a framework for a hybrid social recommendation system.
Different data hybridization approaches on probabilistic latent semantic
analysis are experimented. Based on this flexible probabilistic model, network
regularization and model blending approaches are applied on probabilistic
latent semantic analysis model as a solution for social trust network usage
throughout the collaborative filtering process. The proposed model has
outperformed the baseline methods in our experiments. As a result of the
research, it is shown that the proposed methods successfully model the rating
and social trust data together in a theoretically principled way.
22. Soner Kara An
Ontology-Based Retrieval System Using Semantic Indexing
Abstract:
In this thesis, we present an ontology-based
information extraction and retrieval system and its application to soccer
domain. In general, we deal with three issues in semantic search, namely,
usability, scalability and retrieval performance. We propose a keyword-based
semantic retrieval approach. The performance of the system is improved
considerably using domain-specific information extraction, inference and rules.
Scalability is achieved by adapting a semantic indexing approach. The system is
implemented using the state-of-the-art technologies in SemanticWeb and its
performance is evaluated against traditional systems as well as the query
expansion methods. Furthermore, a detailed evaluation is provided to observe the
performance gain due to domain-specific information extraction and inference.
Finally, we show how we use semantic indexing to solve simple structural
ambiguities.