Computer Sciences Commons^™

Routing In Overlay Multicast Networks, Sherlia Y. Shi, Jonathan S. Turner

All Computer Science and Engineering Research

Multicast servises can be provided either as a basic network service or as an application-layer service. Higher level multicast implementations often provide more sophisticated features, and since they don't require network supoprt for multicast, they can provide multicast services, where no network layer support is available. Overlay multicast networks offer an intermediate option, potentially combining the flexibility and advanced features of application layer multicast with the greater efficiency of network layer multicast. Overlay multicast networks play an important role in the Internet. Indeed, since Internet Service Providers have been slow to enable IP multicast in their networks, Internet multicast is …

Generalized Rad Module Interface Specification Of The Field-Programmable Port Extender (Fpx) Version 2.0, David E. Taylor, John W. Lockwood, Sarang Dharmapurikar

All Computer Science and Engineering Research

The Field-programmable Port eXtender (FPX) provides dynamic, fast, and flexible mechanisms to process data streams at the ports of the Washington University Gigabit Switch (WUGS-20). By performing all computations in FPGA hardware, cells and packets can be processed at the full line speed of the transmission interface, currently 2.4 Gbits/sec. In order to design and implement portable hardware modules for the Reprogrammable Application Devide (RAD) on the FPX board, all modules should conform to a standard interface. This standard interface specifies how modules receive and transmit ATM cells of data flows, prevent data loss during reconfiguration, and access off-chip memory. …

Incorporating Window-Based Passage-Level Evidence In Document Retrieval, Wensi Xi, Richard Xu-Rong, Christopher Soo Guan Khoo, Ee Peng Lim

Research Collection School Of Computing and Information Systems

This study investigated whether document retrieval can be improved if documents are divided into smaller sub-documents or passages and the retrieval score for these passages are incorporated in the final retrieval score for the whole document. The documents were segmented by sliding a window of a certain size across the document and extracting the words displayed each time the window stopped. A retrieval score was calculated for each of the passages extracted and the highest score obtained by a passage of that size was taken as the document’s passage-level score for that window size. A range of window sizes was …

Unified Modeling Language: A Complexity Analysis, Keng Siau, Q. Cao

Research Collection School Of Computing and Information Systems

Unified Modeling Language (UML) is the standard visual modeling language for Object Oriented (OO) systems development, but it has been criticized for its complexity, inconsistent semantics, and ambiguous constructs. A set of complexity indices for UML and the nine diagramming techniques in UML was compiled recently. The complexity analysis is formulated based on the number of constructs, associations, roles, and so forth, in a modeling method. We argue that this set of metrics provides an indication of the theoretical complexity of the modeling methods. On the other hand, the theoretical complexity of the modeling methods does not necessarily relate to …

Fuzzy Modeling Approach For Integrated Assessments Using Cultural Theory, Adnan Yazici, Fred E. Petry, Curt Pendergraft

Turkish Journal of Electrical Engineering and Computer Sciences

It has already been noted that the accurate prediction of societal responses requires the use of a formal model based on some social or cultural taxonomy. One such taxonomic candidate is Cultural Theory (CT). CT argues that all societies, irrespective of time or place, are informed by their underlying worldviews, which must be more or less Hierarchic, more or less Individualistic, more or less Egalitarian, and more or less Fatalistic. This approach appears to have a potential for cross-temporal and spatial comparisons that makes it a particularly attractive instrument for a study of the human dimensions of global climate change. …

Advances In Computer And Information Sciences: From Abacus To Holonic Agents, Tuncer Ören

Turkish Journal of Electrical Engineering and Computer Sciences

The shift of paradigm emphasizing the importance of the ability to process knowledge rather then being knowledgeable is stressed. A taxonomy of knowledge processing tools, machines, or systems is offered. Major possibilities for future achievements that the author would like to underline are listed with emphasis on agent technology, agent-directed simulation, holonic agents, holonic-agent simulation, and contribution of system theories for cognitive abilities such as understanding, learning, adaptation, and anticipation in computerization.

Bag Distributed Real-Time Operating System And Task Migration, Beki̇r Tevfi̇k Akgün

Turkish Journal of Electrical Engineering and Computer Sciences

BAG is a distributed operating system designed for real-time applications which is run on a distributed real-time system. The heterogeneously distributed BAG system consists of nodes which have VME-bus chassis, different types of processor modules, and an interconnection network. The operating system has three main parts having distributed properties: task migration, load balancing and a distributed file system. Heterogeneous task migration is based on the extended finite state machine (EFSM) programming model. The EFMS model has also eased the implementation of the migration mechanism. The load balancing algorithm is centralized in one node. But the overall system will be a …

Avalanche And Bit Independence Properties For The Ensembles Of Randomly Chosen N \Times N S-Boxes, Işil Vergi̇li̇, Melek D. Yücel

Turkish Journal of Electrical Engineering and Computer Sciences

Cryptographic test methods such as avalanche, strict avalanche and bit independence criteria, which measure the degree of security of the s-boxes of substitution-permutation networks, are applied to randomly generated ensembles of ( n \times n \) s-boxes. Statistical analysis of experimental data directs the work towards defining ``relative errors'' and examining the avalanche and strict avalanche criteria within ``relative error ranges''. Histograms of relative errors in each ensemble are evaluated, and combining the results of different ensembles corresponding to different values of the s-box size, variations of maximum relative errors versus the size of the s-box are depicted. Some predictions …

Accurate Parameter Estimation For An Articulatory Speech Synthesizer With An Improved Neural Network Mapping, Hali̇s Altun, Tankut Yalçinöz, K. Mervyn Curtis

Turkish Journal of Electrical Engineering and Computer Sciences

Neural network (NN) applications have recently been employed to extract the parameters of an articulatory speech synthesizer from a given speech signal. Results from these attempts showed that a single NN is insufficient to cover all of the possible configurations uniquely. Moreover, apart from their computational advantages, NN mapping is so far not superior to the other mapping techniques [1]. Thus there is a clear need to improve NN solution to the inverse problem. Results from our earlier experiments with an articulatory speech synthesizer have shown that the statistical characteristic of the articulatory target pattern vectors can be exploited for …

Performance Evaluation Of Safer K-64 And S-Boxes Of The Safer Family, Ekrem Aras, Melek D. Yücel

Turkish Journal of Electrical Engineering and Computer Sciences

If the characteristics of s-boxes of the SAFER family of ciphers are examined for the criteria of strict avalanche, bit independence, and XOR table distribution, experiments show that the ``exponentiating'' s-box has a weakness for an input difference of 128 (=10000000_{2}) and the ``logarithm-taking'' s-box has a weakness for an input difference of 253 (=11111101_{2}). However, since these experiments are performed by isolating the s-boxes from the general structure, they do not necessarily indicate a weakness in the overall algorithm. We propose a quick and rough test method, called the avalanche weight distribution criterion, to evaluate the overall performance of …

A More Efficient Design And Implementation Of Cal Programs In Natural Science Using Object-Oriented Technology, Jurgen Friedrich

Turkish Journal of Electrical Engineering and Computer Sciences

With the amount and complexity of science topics and applications increasing, the need for appropriate and effective science education is constantly growing. Computer-based education is very promising to help both teachers and learners in their difficult task, which involves complex psychological processes. This complexity is reflected in high demands on the design and implementation methods used to create computer-assisted learning (CAL) programs. Due to their concepts, flexibility, maintainability and extended library resources, object-oriented technology (OOT) is very suitable to producing this type of pedagogical tool. The introduced approach is demonstrated by a basketball simulation program for instruction in Newtonian mechanics …

Ota-C Based Proportional-Integral-Derivative (Pid) Controller And Calculating Optimum Parameter Tolerances, Cevat Erdal, Ali̇ Toker, Cevdet Acar

Turkish Journal of Electrical Engineering and Computer Sciences

Proportional-integral-derivative (PID) controllers are one of the most important control elements used in the process control industry. In practice, operational amplifiers are generally used in analog controllers. On the other hand, the operational transconductance amplifiers recently developed, which have some positive properties compared to operational amplifiers, are not used in analog controller design at present. Furthermore, the optimum parameter tolerances for the proposed PID circuit by the use of parameter sensitivities are determined. These tolerances keep the relative error at the output of the controller due to parameter variations in the tolerance region.

Scalar Wave Diffraction By A Perfectly Soft Infinitely Thin Circular Ring, Fati̇h Di̇kmen, Ertuğrul Karaçuha, Yury Alexanderovich Tuchkin

Turkish Journal of Electrical Engineering and Computer Sciences

A new strong mathematically rigorous and numerically effective method for solving the boundary value problem of scalar (for example acoustic) wave diffraction by a perfectly soft (Dirichlet boundary condition) infinitely thin circular ring is proposed. The method is based on the combination of the Orthogonal Polynomials Approach, and on the ideas of the methods of analytical regularization. As a result of the suggested regularization procedure, the initial boundary value problem is equivalently reduced to the infinite system of the linear algebraic equations of the second kind, i.e., to an equation of the type ( (I + H) x = b …

A Web-Enabled Temporal Database Human Resources Application, Joseph A. Brooke Iii

UNF Graduate Theses and Dissertations

Despite the inclusion of a variety of time-related or 'temporal' datatypes in the SQL-92 standard, vendors of commercially-available Relational Database Management Systems (RDBMS) have universally elected to not fully comply with the standard. Perhaps even more frustrating is the fact that each vendor has chosen to include a different subset of temporal datatypes than their competitors, with most vendors adding a proprietary twist to their datatypes not even contained within the standard.

This lack of conformity has left users of these database products faced with a difficult choice: either avoid temporal functionality within their database applications or develop and manage …

Arc - An Oai Service Provider For Digital Library Federation, Xiaoming Liu, Kurt Maly, Mohammad Zubair, Michael L. Nelson

Computer Science Faculty Publications

The usefulness of the many on-line journals and scientific digital libraries that exist today is limited by the inability to federate these resources through a unified interface. The Open Archive Initiative (OAI) is one major effort to address technical interoperability among distributed archives. The objective of OAI is to develop a framework to facilitate the discovery of content in distributed archives. In this paper, we describe our experience and lessons learned in building Arc, the first federated searching service based on the OAI protocol. Arc harvests metadata from several OAI compliant archives, normalizes them, and stores them in a search …

Smart Objects And Open Archives, Michael L. Nelson, Kurt Maly

Computer Science Faculty Publications

Within the context of digital libraries (DLs), we are making information objects "first-class citizens". We decouple information objects from the systems used for their storage and retrieval, allowing the technology for both DLs and information content to progress independently. We believe dismantling the stovepipe of "DL-archive-content" is the first step in building richer DL experiences for users and insuring the long-term survivability of digital information. To demonstrate this partitioning between DLs, archives and information content, we introduce "buckets": aggregative, intelligent, object-oriented constructs for publishing in digital libraries. Buckets exist within the "Smart Object, Dumb Archive" (SODA) DL model, which promotes …

Buckets: Smart Objects For Digital Libraries, Michael L. Nelson

Computer Science Faculty Publications

Current discussion of digital libraries (DLs) is often dominated by the merits of the respective storage, search and retrieval functionality of archives, repositories, search engines, search interfaces and database systems. While these technologies are necessary for information management, the information content is more important than the systems used for its storage and retrieval. Digital information should have the same long-term survivability prospects as traditional hardcopy information and should be protected to the extent possible from evolving search engine technologies and vendor vagaries in database management systems. Information content and information retrieval systems should progress on independent paths and make limited …

Efficient Algorithms For Graphs With Few P-4’S, Luitpold Babel, Ton Kloks, Jan Kratochvíl, Dieter Kratsch, Kaiko Müller, Stephan Olariu

Computer Science Faculty Publications

We show that a large variety of NP-complete problems can be solved efficiently for graphs with 'few' P₄'s. We consider domination problems (domination, total domination, independent domination. connected domination and dominating clique), the Steiner tree problem, the vertex ranking problem, the pathwidth problem, the path cover number problem, the hamiltonian circuit problem, the list coloring problem and the precoloring extension problem. We show that all these problems can be solved in linear time for the class of (q,q - 4)-graphs, for every fixed q. These are graphs for which no set of at most q. vertices induces more …