Browsing by Subject "Systems engineering"

Now showing 1 - 5 of 5

Open Access
A beam search algorithm to optimize robustness under random machine breakdowns and processing time variability
(Institute of Industrial Engineers, 2007) Gören, S.; Sabuncuoğlu, İhsan
The vast majority of the machine scheduling research assumes complete information about the scheduling problem and a static environment in which scheduling systems operate. In practice, however, scheduling systems are subject to considerable uncertainty in dynamic environments. The ability to cope with the uncertainty in scheduling process is becoming increasingly important in today's highly dynamic and competitive business environments. In the literature, two approaches have appeared as the effective way: reactive and proactive scheduling. The objective in reactive scheduling is to revise schedules as necessary, while proactive scheduling attempts to incorporate future disruptions when generating schedules. In this paper we take a proactive scheduling approach to solve a machine scheduling problem with two sources of uncertainty: processing time variability and machine breakdowns. We define two robustness measures and develop a heuristic based on beam search methodology to optimize them. The computational results show that the proposed algorithms perform significantly better than a number of heuristics available in the literature.
Open Access
Keyframe reduction techniques for motion capture data
(IEEE, 2008-05) Önder, Onur; Güdükbay, Uğur; Özgüç, Bülent; Erdem, T.; Erdem, Ç.; Özkan, M.
Two methods for keyframe reduction of motion capture data are presented. Keyframe reduction of motion capture data enables animators to easily edit motion data with smaller number of keyframes. One of the approaches achieves keyframe reduction and noise removal simultaneously by fitting a curve to the motion information using dynamic programming. The other approach uses curve simplification algorithms on the motion capture data until a predefined threshold of number of keyframes is reached. Although the error rate varies with different motions, the results show that curve fitting with dynamic programming performs as good as curve simplification methods. ©2008 IEEE.
Open Access
Robust transmission of multi-view video streams using flexible macroblock ordering and systematic LT codes
(IEEE, 2007) Argyropoulos, S.; Tan, A. Serdar; Thomos, N.; Arıkan, Erdal; Strintzis, M. G.
The transmission of fully compatible H.264/AVC multi-view video coded streams over packet erasure networks is examined. Macroblock classification into unequally important slice groups is considered using the Flexible Macroblock Ordering (FMO) tool of H.264/AVC Systematic LT codes are used for error protection due to their low complexity and advanced performance. The optimal slice grouping and channel rate allocation are jointly determined by an iterative optimization algorithm based on dynamic programming. The experimental evaluation clearly demonstrates the validity of the proposed method.
Open Access
Towards a quality service layer for Web 2.0
(Springer, 2011-12) Schaal, M.; Davenport, David; Çevik, Ali Hamdi
Despite the help of search engines and Web directories, identifying high quality content becomes increasingly difficult as the Internet gets ever more crowded with information. Prior approaches for filtering and searching content with respect to user-specific preferences do exist: Recommendation engines employ collaborative filtering to support subjective selection, (semi-)automatic page ranking algorithms utilize the hypertext link structure of the World Wide Web to assess page importance, and trust-based systems employ social network analysis to determine the most suitable Web pages. The use of implicit and explicit user feedback, however, is often either ignored or its exploitation is limited to isolated Web sites. We thus propose a quality overlay framework that enables the collection and processing of user-feedback, and the subsequent presentation of quality-enabled content for any Web-site. We present the quality overlay framework, propose an architecture for its realization, and validate our approach by scenarios and a detailed design with sample implementation. © 2011 Springer-Verlag.
Open Access
Turkey: a report on computer graphics education
(Technews, 1996) Özgüç, B.
In a formal or an informal manner, computer graphics has been a field of research and education since the early 1970s in Turkey. The earlier examples of academic research work came from Istanbul Technical University and Middle East Technical University in Ankara. Istanbul Technical University research efforts were basically on computer-aided design, whereas at the Middle East Technical University, more theoretical computer graphics work has been carried on.Two examples can be given of early theoretical graphics work: A hidden line elimination algorithm by Ibrahim Canbulat, and an automated drafting algorithm by the author [2, 3]. To the best of my knowledge, the earliest official computer graphics course was offered at the Middle East Technical University in 1979. With the establishment of Bilkent University in Ankara, the first private university in Turkey, computer graphics became an official track of study, not only in computer engineering, but in fine arts as well.In this paper, we examine the current state of computer graphics education in Turkey under two main headings. First, the educational activities within the departments of computer science will be examined. Then, the educational activities within the schools of art and design will be looked at. In order to find out the educational activities at various universities, we have written to 52 departments at 40 universities. The information given in this report is based on the responses from these departments. Many departments at various schools offer technical drawing courses by the use of drafting software. These have not been classified as computer graphics courses.