Browsing by Subject "Information Systems"

Now showing 1 - 3 of 3

Open Access
A case-based model for assessing the effectiveness of information systems outsourcing
(Routledge, 2013) Uçar E.; Bilgen, S.
The objective of the research reported in this paper is to construct a model for assessing the effectiveness of Information Systems (IS) outsourcing. “Lack of in-house expertise” and “cost effectiveness” are widely accepted as major factors of motivation for IS outsourcing. In contrast with the decision models which are executed before an outsourcing engagement (a-priori), this effectiveness assessment model will be an a-posteriori guide which will enable clients to assess their outsourcing performance and re-evaluate their business and management strategies. Although various decision models and analytical frameworks have been proposed before, the literature is not abundant on a complete qualitative model. This paper examines the factors for outsourcing effectiveness through qualitative research conducted with multiple case studies for information systems developed for public organizations in the specific context of Turkey. A conceptual model consisting of various hypotheses is constructed and qualitatively evaluated.
Open Access
A rule-based video database system architecture
(Elsevier, 2002) Dönderler, M. E.; Ulusoy, Özgür; Güdükbay, Uğur
We propose a novel architecture for a video database system incorporating both spatio-temporal and semantic (keyword, event/activity and category-based) query facilities. The originality of our approach stems from the fact that we intend to provide full support for spatio-temporal, relative object-motion and similarity-based object-trajectory queries by a rule-based system utilizing a knowledge-base while using an object-relational database to answer semantic-based queries. Our method of extracting and modeling spatio-temporal relations is also a unique one such that we segment video clips into shots using spatial relationships between objects in video frames rather than applying a traditional scene detection algorithm. The technique we use is simple, yet novel and powerful in terms of effectiveness and user query satisfaction: video clips are segmented into shots whenever the current set of relations between objects changes and the video frames, where these changes occur, are chosen as keyframes. The directional, topological and third-dimension relations used for shots are those of the keyframes selected to represent the shots and this information is kept, along with frame numbers of the keyframes, in a knowledge-base as Prolog facts. The system has a comprehensive set of inference rules to reduce the number of facts stored in the knowledge-base because a considerable number of facts, which otherwise would have to be stored explicitly, can be derived by rules with some extra effort. © 2002 Elsevier Science Inc. All rights reserved.
Open Access
Vertical framing of superimposed signature files using partial evaluation of queries
(Elsevier, 1997) Kocberbera, S.; Can, F.
A new signature file method, Multi-Frame Signature File (MFSF), is introduced by extending the bit-sliced signature file method. In MFSF, a signature file is divided into variable sized vertical frames with different on-bit densities to optimize the response time using a partial query evaluation methodology. In query evaluation the on-bits of the lower on-bit density frames are used first. As the number of query terms increases, the number of query signature on-bits in the lower on-bit density frames increases and the query stopping condition is reached in fewer evaluation steps. Therefore, in MFSF, the query evaluation time decreases for increasing numbers of query terms. Under the sequentiality assumption of disk blocks, in a PC environment with 30 ms average disk seek time, MFSF provides a projected worst-case response time of 3.54 seconds for a database size of one million records in a uniform distribution multi-term query environment with 1–5 terms per query. Due to partial evaluation, this desired response time is guaranteed for queries with several terms. The comparison of MFSF with the inverted file approach shows that MFSF provides promising research opportunities.