http://eresearch.ozyegin.edu.tr:80/xmlui The eResearch@Ozyegin digital repository system captures, stores, indexes, preserves, and distributes digital research material. Thu, 17 May 2012 10:19:03 GMT 2012-05-17T10:19:03Z http://hdl.handle.net/10679/163 Telecommunications network design with multiple technologies Gzara, Fatma; Erkut, Erhan In this paper we consider a telecommunications network design problem allowing for multiple technologies. The problem arises in wide-area network and metro-area network design for which a combination of Technologies may be necessary due to high traffic volumes, long-distance transmission, and design restrictions. The network design problem builds the best network to channel traffic between a set of origins and destinations, which requires selecting links, equipping them with fiber, deciding on the type of technology, and locating switches. The goal is to minimize the total cost of the network, which accounts for the flow cost, the fiber and technology costs, and the switch-location cost. We model the problem using a multicommodity network design formulation with side constraints. We apply Benders decomposition to the problem and develop a twophase solution method that uses a number of improvements over the basic Benders algorithm. We present promising results on randomly generated test problems. Fri, 31 Dec 2010 22:00:00 GMT http://hdl.handle.net/10679/163 2010-12-31T22:00:00Z http://hdl.handle.net/10679/161 Integrated Airline Schedule Design and Fleet Assignment: Polyhedral Analysis and Benders’ Decomposition Approach Sherali, Hanif D.; Bae, Ki-Hwan; Haouari, Mohamed The main airline operations consist of schedule planning, fleet assignment, aircraft routing, and crew scheduling. To improve profitability, we present in this paper an integrated fleet assignment model with schedule planning by simultaneously considering optional flight legs to select along with the assignment of aircraft types to all scheduled legs. In addition, we consider itinerary-based demands for multiple fare classes. A polyhedral analysis is conducted of the proposed mixed-integer programming model to tighten its representation via several classes of valid inequalities. Solution approaches are developed by applying Benders' decomposition method to the resulting lifted model, and computational results are presented using real data obtained from a major U.S. airline to demonstrate the efficacy of the proposed procedures. Thu, 31 Dec 2009 22:00:00 GMT http://hdl.handle.net/10679/161 2009-12-31T22:00:00Z http://hdl.handle.net/10679/160 Accommodating Shifting User Expectations Cribb, Gülçin; Schmidt, Janine Whether they are called netgeners, born digital, digital natives, screenagers, Generation Y or Generation Z, the current and next generation of library users want everything, and they want it now. They communicate constantly, tapping and swiping I-Phones, I-Pads and androids as they broadcast their daily activities via Twitter and Facebook. They rarely sit still and do nothing and do not discriminate in using technology between their personal and professional lives – studying, working and living are all integrated in the mashed-up infosphere. They are readers, viewers, listeners, writers and speakers and use a variety of media. What use do they make of libraries? What do they want from us? How do library buildings accommodate their needs? One emerging trend is the need for silence – the generation who communicates constantly via their fingers and thumbs and the photographic record seems to want quieter spaces in libraries. They remain voyeurs and view others at work and play – but more silently it seems, although they still want opportunities to meet with others and discuss learning and life – preferably with food and drink. They are serious about what they do and want to be treated with respect and empathy. Digital natives want their information resources delivered seamlessly with voice and vision included, not just words on paper or on a screen. In Google we Trust is their mantra and if it is on the web, it must be true. Digital natives have difficulty evaluating what they find and tend to regard all information as equal in value. Their approach to scholarship and learning needs to be developed. They regard the full output of scholarly work in one continuum whether it is real or virtual. And the library buildings for this generation? Digital natives want attractive buildings which are easy to use and provide pleasant environments and a relaxing space with plenty of technology. They want to plug in, power up and prowl the internet. They want “high tech” but they also want “high touch”. They want individual personalized help wherever they might be – and at varying times of day – my place, my space, my time – and targeted to my needs. The paper explores the needs of digital natives and some of the possible changes in library building design to accommodate the shifting sand of user needs. Wed, 21 Sep 2011 21:00:00 GMT http://hdl.handle.net/10679/160 2011-09-21T21:00:00Z http://hdl.handle.net/10679/159 An In-Depth Look at Prior Art in Fast Round-Robin Arbiter Circuits Uğurdağ, Fatih; Baskirt, Onur Arbiters are found where shared resources exist such as busses, switching fabrics, processing elements. Round-robin is a fair arbitration method, where requestors get near-equal shares of a common resource or service. Round-robin arbitration (RRA) finds use in network switches/routers and processor boards/systems as well as many other applications that have concurrency. Today's electronic systems require arbiters with hundreds of ports (e.g., switching fabrics with virtual I/O queues) and clock speeds near the limits of even the latest microelectronics fabrication processes/libraries. Achieving high clock speeds in the presence of large number of ports is only possible with highly parallel arbiter architectures. This paper presents an in-depth literature survey of previous work on this problem. It looks at RRA work in the literature in a bigger context, then defines the typical RRA problem (RRA_typical), and specifically investigates work on fast architectures that solve the RRA_typical problem. There are five such works that are really competitive. This report takes a very in-depth look at these works. It explains each architecture and how/why it works from a unique perspective that cannot be found in the original publication of that architecture. It also proposes improvements to these architectures. We wrote generators for the improved versions of these architectures. We will share a summary of synthesis results in this report – although a detailed account of how these results were obtained and their analysis is the subject of another (upcoming) publication Sun, 31 Jul 2011 21:00:00 GMT http://hdl.handle.net/10679/159 2011-07-31T21:00:00Z