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Articles 91 - 120 of 125

Full-Text Articles in Theory and Algorithms

Efficient Corona Training Protocols For Sensor Networks, Alan A. Bertossi, Stephan Olariu, Cristina M. Pinotti Jan 2008

Efficient Corona Training Protocols For Sensor Networks, Alan A. Bertossi, Stephan Olariu, Cristina M. Pinotti

Computer Science Faculty Publications

Phenomenal advances in nano-technology and packaging have made it possible to develop miniaturized low-power devices that integrate sensing, special-purpose computing, and wireless communications capabilities. It is expected that these small devices, referred to as sensors, will be mass-produced and deployed, making their production cost negligible. Due to their small form factor and modest non-renewable energy budget, individual sensors are not expected to be GPS-enabled. Moreover, in most applications, exact geographic location is not necessary, and all that the individual sensors need is a coarse-grain location awareness. The task of acquiring such a coarse-grain location awareness is referred to as training. …

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Mining Web-Functional Dependencies For Flexible Information Access, Saverio Perugini, Naren Ramakrishnan Oct 2007

Mining Web-Functional Dependencies For Flexible Information Access, Saverio Perugini, Naren Ramakrishnan

Computer Science Faculty Publications

We present an approach to enhancing information access through Web structure mining in contrast to traditional approaches involving usage mining. Specifically, we mine the hardwired hierarchical hyperlink structure of Web sites to identify patterns of term-term co-occurrences we call Web functional dependencies (FDs). Intuitively, a Web FD ‘x y’ declares that all paths through a site involving a hyperlink labeled x also contain a hyperlink labeled y. The complete set of FDs satisfied by a site help characterize (flexible and expressive) interaction paradigms supported by a site, where a paradigm is the set of explorable sequences therein. …

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Residual-Based Measurement Of Peer And Link Lifetimes In Gnutella Networks, Xiaoming Wang, Zhongmei Yao, Dmitri Loguinov May 2007

Residual-Based Measurement Of Peer And Link Lifetimes In Gnutella Networks, Xiaoming Wang, Zhongmei Yao, Dmitri Loguinov

Computer Science Faculty Publications

Existing methods of measuring lifetimes in P2P systems usually rely on the so-called create-based method (CBM), which divides a given observation window into two halves and samples users "created" in the first half every Delta time units until they die or the observation period ends. Despite its frequent use, this approach has no rigorous accuracy or overhead analysis in the literature. To shed more light on its performance, we flrst derive a model for CBM and show that small window size or large Delta may lead to highly inaccurate lifetime distributions. We then show that create-based sampling exhibits an inherent …

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On Node Isolation Under Churn In Unstructured P2p Networks With Heavy-Tailed Lifetimes, Zhongmei Yao, Xiaoming Wang, Dmitri Loguinov May 2007

On Node Isolation Under Churn In Unstructured P2p Networks With Heavy-Tailed Lifetimes, Zhongmei Yao, Xiaoming Wang, Dmitri Loguinov

Computer Science Faculty Publications

Previous analytical studies [12], [18] of unstructured P2P resilience have assumed exponential user lifetimes and only considered age-independent neighbor replacement. In this paper, we overcome these limitations by introducing a general node-isolation model for heavy-tailed user lifetimes and arbitrary neighbor-selection algorithms. Using this model, we analyze two age-biased neighbor-selection strategies and show that they significantly improve the residual lifetimes of chosen users, which dramatically reduces the probability of user isolation and graph partitioning compared to uniform selection of neighbors. In fact, the second strategy based on random walks on age-weighted graphs demonstrates that for lifetimes with infinite variance, the system …

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Percentage-Based Hybrid Pattern Training With Neural Network Specific Cross Over, Sheng-Uei Guan, Kiruthika Ramanathan Mar 2007

Percentage-Based Hybrid Pattern Training With Neural Network Specific Cross Over, Sheng-Uei Guan, Kiruthika Ramanathan

Research Collection School Of Computing and Information Systems

In this paper, a new weight-setting method is proposed to improve the training time and generalization accuracy of feed-forward neural networks. This method introduces a percentage-based hybrid pattern training (PHP) scheme and aims to provide a solution to the problem dependency of other Genetic Algorithm (GA)-based Neural Network weight-setting methods. A neural network is trained using a neural network specific GA until a certain percentage of the training patterns is learned. The weights thus obtained are used as the initial weights for backpropagation (BP) training, which is then applied to complete the network training. Further improvement to the method was …

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Modeling Heterogeneous User Churn And Local Resilience Of Unstructured P2p Networks, Zhongmei Yao, Derek Leonard, Dmitri Loguinov, Xiaoming Wang Nov 2006

Modeling Heterogeneous User Churn And Local Resilience Of Unstructured P2p Networks, Zhongmei Yao, Derek Leonard, Dmitri Loguinov, Xiaoming Wang

Computer Science Faculty Publications

Previous analytical results on the resilience of unstructured P2P systems have not explicitly modeled heterogeneity of user churn (i.e., difference in online behavior) or the impact of in-degree on system resilience. To overcome these limitations, we introduce a generic model of heterogeneous user churn, derive the distribution of the various metrics observed in prior experimental studies (e.g., lifetime distribution of joining users, joint distribution of session time of alive peers, and residual lifetime of a randomly selected user), derive several closed-form results on the transient behavior of in-degree, and eventually obtain the joint in/out degree isolation probability as a simple …

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Interacting With Web Hierarchies, Saverio Perugini, Naren Ramakrishnan Jun 2006

Interacting With Web Hierarchies, Saverio Perugini, Naren Ramakrishnan

Computer Science Faculty Publications

Web site interfaces are a particularly good fit for hierarchies in the broadest sense of that idea, i.e. a classification with multiple attributes, not necessarily a tree structure. Several adaptive interface designs are emerging that support flexible navigation orders, exposing and exploring dependencies, and procedural information-seeking tasks. This paper provides a context and vocabulary for thinking about hierarchical Web sites and their design. The paper identifies three features that interface to information hierarchies. These are flexible navigation orders, the ability to expose and explore dependencies, and support for procedural tasks. A few examples of these features are also provided

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The Reliability Of The Computer Communication Networks Including Mobile Nodes, Sahin Yasar Apr 2006

The Reliability Of The Computer Communication Networks Including Mobile Nodes, Sahin Yasar

Electrical & Computer Engineering Theses & Dissertations

The wireless computer networks have an uncertainty in their structures aside from their big advantages for the users. The environmental conditions, changing locations of the mobile hosts and the changing components in the system can easily affect their reliability. In order to know a system capability performing its functions, keep the reliability at a certain level and/or detect the deficiency of the system, it is necessary to analyze the reliability of a computer communication network including the wired and wireless parts. But the above reasons also make the analysis and a unique solution difficult so a set of algorithms is …

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Realtime Query Expansion And Procedural Interfaces For Information Hierarchies, Saverio Perugini Jan 2006

Realtime Query Expansion And Procedural Interfaces For Information Hierarchies, Saverio Perugini

Computer Science Faculty Publications

We demonstrate the use of two user interfaces for interacting with web hierarchies. One uses the dependencies underlying a hierarchy to perform real-time query expansion and, in this way, acts as an in situ feedback mechanism. The other enables the user to cascade the output from one interaction to the input of another, and so on, and, in this way, supports procedural information-seeking tasks without disrupting the flow of interaction.

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Group Key Management In Wireless Ad-Hoc And Sensor Networks, Mohammed A. Moharrum Jan 2006

Group Key Management In Wireless Ad-Hoc And Sensor Networks, Mohammed A. Moharrum

Computer Science Theses & Dissertations

A growing number of secure group applications in both civilian and military domains is being deployed in WAHNs. A Wireless Ad-hoc Network (WARN) is a collection of autonomous nodes or terminals that communicate with each other by forming a multi-hop radio network and maintaining connectivity in a decentralized manner. A Mobile Ad-hoc Network (MANET) is a special type of WARN with mobile users. MANET nodes have limited communication, computational capabilities, and power. Wireless Sensor Networks (WSNs) are sensor networks with massive numbers of small, inexpensive devices pervasive throughout electrical and mechanical systems and ubiquitous throughout the environment that monitor and …

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On Static And Dynamic Partitioning Behavior Of Large-Scale Networks, Derek Leonard, Zhongmei Yao, Xiaoming Wang, Dmitri Loguinov Nov 2005

On Static And Dynamic Partitioning Behavior Of Large-Scale Networks, Derek Leonard, Zhongmei Yao, Xiaoming Wang, Dmitri Loguinov

Computer Science Faculty Publications

In this paper, we analyze the problem of network disconnection in the context of large-scale P2P networks and understand how both static and dynamic patterns of node failure affect the resilience of such graphs. We start by applying classical results from random graph theory to show that a large variety of deterministic and random P2P graphs almost surely (i.e., with probability 1-o(1)) remain connected under random failure if and only if they have no isolated nodes. This simple, yet powerful, result subsequently allows us to derive in closed-form the probability that a P2P network develops isolated nodes, and therefore partitions, …

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Poster Session A: Address Auto-Configuration In Mobile Ad Hoc Networks Using Olsr, M.U. Saleem, Shoaib Mukhtar Aug 2005

Poster Session A: Address Auto-Configuration In Mobile Ad Hoc Networks Using Olsr, M.U. Saleem, Shoaib Mukhtar

International Conference on Information and Communication Technologies

Mobile Ad Hoc Networks is dynamic multi-hop network that is formed by a set of mobile wireless nodes that are sharing the same bandwidth. So every node possibly acts as a host as well as a router. In traditional networks, hosts can depend on the central servers like DHCP for IP assignment and management, but it cannot be extended to MANET due to its distributed and dynamic nature. Many solutions have been proposed, amongst them some are try to extend the stateless configuration of IPv6 for MANET; others distribute IP addresses among nodes (using binary distribution). Most of these proposed …

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Automatically Discovering The Number Of Clusters In Web Page Datasets, Zhongmei Yao Jun 2005

Automatically Discovering The Number Of Clusters In Web Page Datasets, Zhongmei Yao

Computer Science Faculty Publications

Clustering is well-suited for Web mining by automatically organizing Web pages into categories, each of which contains Web pages having similar contents. However, one problem in clustering is the lack of general methods to automatically determine the number of categories or clusters. For the Web domain in particular, currently there is no such method suitable for Web page clustering. In an attempt to address this problem, we discover a constant factor that characterizes the Web domain, based on which we propose a new method for automatically determining the number of clusters in Web page data sets. We discover that the …

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Rcu Semantics: A First Attempt, Paul E. Mckenney, Jonathan Walpole Jan 2005

Rcu Semantics: A First Attempt, Paul E. Mckenney, Jonathan Walpole

Computer Science Faculty Publications and Presentations

There is not yet a formal statement of RCU (read-copy update) semantics. While this lack has thus far not been an impediment to adoption and use of RCU, it is quite possible that formal semantics would point the way towards tools that automatically validate uses of RCU or that permit RCU algorithms to be automatically generated by a parallel compiler. This paper is a first attempt to supply a formal definition of RCU. Or at least a semi-formal definition: although RCU does not yet wear a tux (though it does run in Linux), at least it might yet wear some …

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Recommender Systems Research: A Connection-Centric Survey, Saverio Perugini, Marcos André Gonçalves, Edward A. Fox Sep 2004

Recommender Systems Research: A Connection-Centric Survey, Saverio Perugini, Marcos André Gonçalves, Edward A. Fox

Computer Science Faculty Publications

Recommender systems attempt to reduce information overload and retain customers by selecting a subset of items from a universal set based on user preferences. While research in recommender systems grew out of information retrieval and filtering, the topic has steadily advanced into a legitimate and challenging research area of its own. Recommender systems have traditionally been studied from a content-based filtering vs. collaborative design perspective. Recommendations, however, are not delivered within a vacuum, but rather cast within an informal community of users and social context. Therefore, ultimately all recommender systems make connections among people and thus should be surveyed from …

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Staging Transformations For Multimodal Web Interaction Management, Michael Narayan, Christopher Williams, Saverio Perugini, Naren Ramakrishnan Jan 2004

Staging Transformations For Multimodal Web Interaction Management, Michael Narayan, Christopher Williams, Saverio Perugini, Naren Ramakrishnan

Computer Science Faculty Publications

Multimodal interfaces are becoming increasingly ubiquitous with the advent of mobile devices, accessibility considerations, and novel software technologies that combine diverse interaction media. In addition to improving access and delivery capabilities, such interfaces enable flexible and personalized dialogs with websites, much like a conversation between humans. In this paper, we present a software framework for multimodal web interaction management that supports mixed-initiative dialogs between users and websites. A mixed-initiative dialog is one where the user and the website take turns changing the flow of interaction. The framework supports the functional specification and realization of such dialogs using staging transformations – …

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Program Transformations For Information Personalization, Saverio Perugini Jan 2004

Program Transformations For Information Personalization, Saverio Perugini

Computer Science Faculty Publications

Personalization constitutes the mechanisms and technologies necessary to customize information access to the end-user. It can be defined as the automatic adjustment of information content, structure, and presentation. The central thesis of this dissertation is that modeling interaction explicitly in a representation, and studying how partial information can be harnessed in it by program transformations to direct the flow of the interaction, can provide insight into, reveal opportunities for, and define a model for personalized interaction. To evaluate this thesis, a formal modeling methodology is developed for personalizing interactions with information systems, especially hierarchical hypermedia, based on program transformations. The …

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Automatically Generating Interfaces For Personalized Interaction With Digital Libraries, Saverio Perugini, Naren Ramakrishnan, Edward A. Fox Jan 2004

Automatically Generating Interfaces For Personalized Interaction With Digital Libraries, Saverio Perugini, Naren Ramakrishnan, Edward A. Fox

Computer Science Faculty Publications

We present an approach to automatically generate interfaces supporting personalized interaction with digital libraries; these interfaces augment the user-DL dialog by empowering the user to (optionally) supply out-of-turn information during an interaction, flatten or restructure the dialog, and inquire about dialog options. Interfaces generated using this approach for CITIDEL are described.

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Optimal Design Of Engineering Systems Using Mpi-Enabled Genetic Algorithm, S. D. Rajan, D. T. Nguyen, M. D. Deshpande, L. Harrell Jan 2004

Optimal Design Of Engineering Systems Using Mpi-Enabled Genetic Algorithm, S. D. Rajan, D. T. Nguyen, M. D. Deshpande, L. Harrell

Civil & Environmental Engineering Faculty Publications

The focus of this paper is on the development and implementation of a genetic algorithm (GA)-based software system using message passing interface (MPI) protocol and library. A customized form of simple GA used in previous research [1-4] is parallelized. This MPI-enabled version is used to find the solution to finite element based design optimization problems. Results show that an almost linear speedup is obtained on homogenous hardware cluster and, with proper reworking of the software, on heterogeneous hardware cluster.

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Qos Routing Optimization Strategy Using Genetic Algorithm In Optical Fiber Communication Networks, Zhaoxia Wang, Zengqiang Chen, Zhuzhi Yuan Jan 2004

Qos Routing Optimization Strategy Using Genetic Algorithm In Optical Fiber Communication Networks, Zhaoxia Wang, Zengqiang Chen, Zhuzhi Yuan

Research Collection School Of Computing and Information Systems

This paper describes the routing problems in optical fiber networks, defines five constraints, induces and simplifies the evaluation function and fitness function, and proposes a routing approach based on the genetic algorithm, which includes an operator [OMO] to solve the QoS routing problem in optical fiber communication networks. The simulation results show that the proposed routing method by using this optimal maintain operator genetic algorithm (OMOGA) is superior to the common genetic algorithms (CGA). It not only is robust and efficient but also converges quickly and can be carried out simply, that makes it better than other complicated GA.

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Automatic Speaker Identification Using Reusable And Retrainable Binary-Pair Partitioned Neural Networks, Ashutosh Mishra Apr 2003

Automatic Speaker Identification Using Reusable And Retrainable Binary-Pair Partitioned Neural Networks, Ashutosh Mishra

Electrical & Computer Engineering Theses & Dissertations

This thesis presents an extension of the work previously done on speaker identification using Binary Pair Partitioned (BPP) neural networks. In the previous work, a separate network was used for each pair of speakers in the speaker population. Although the basic BPP approach did perform well and had a simple underlying algorithm, it had the obvious disadvantage of requiring an extremely large number of networks for speaker identification with large speaker populations. It also requires training of networks proportional to the square of the number of speakers under consideration, leading to a very large number of networks to be trained …

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The Staging Transformation Approach To Mixing Initiative, Robert Capra, Michael Narayan, Saverio Perugini, Naren Ramakrishnan, Manuel A. Pérez-Quiñones Jan 2003

The Staging Transformation Approach To Mixing Initiative, Robert Capra, Michael Narayan, Saverio Perugini, Naren Ramakrishnan, Manuel A. Pérez-Quiñones

Computer Science Faculty Publications

Mixed-initiative interaction is an important facet of many conversational interfaces, flexible planning architectures, intelligent tutoring systems, and interactive information retrieval systems. Software systems for mixed-initiative interaction must enable us to both operationalize the mixing of initiative (i.e., support the creation of practical dialogs) and to reason in real-time about how a flexible mode of interaction can be supported (e.g., from a meta-dialog standpoint). In this paper, we present the staging transformation approach to mixing initiative, where a dialog script captures the structure of the dialog and dialog control processes are realized through generous use of program transformation techniques (e.g., partial …

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On The Area Of Hypercube Layouts, Ronald I. Greenberg, Lee Guan Sep 2002

On The Area Of Hypercube Layouts, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

This paper precisely analyzes the wire density and required area in standard styles for the hypercube. It shows that the most natural, regular layout of a hypercube of N^2 nodes in the plane, in a NxN grid arrangement, uses floor(2N/3)+1 horizontal wiring tracks for each row of nodes. (In the process, we see that the number of tracks per row can be reduced by 1 with a less regular design, as can also be seen from an independent argument of Bezrukov et al.) This paper also gives a simple formula for the wire density at any cut position and a …

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The Partial Evaluation Approach To Information Personalization, Naren Ramakrishnan, Saverio Perugini Jan 2001

The Partial Evaluation Approach To Information Personalization, Naren Ramakrishnan, Saverio Perugini

Computer Science Faculty Publications

Information personalization refers to the automatic adjustment of information content, structure, and presentation tailored to an individual user. By reducing information overload and customizing information access, personalization systems have emerged as an important segment of the Internet economy. This paper presents a systematic modeling methodology— PIPE (‘Personalization is Partial Evaluation’) — for personalization. Personalization systems are designed and implemented in PIPE by modeling an information-seeking interaction in a programmatic representation. The representation supports the description of information-seeking activities as partial information and their subsequent realization by partial evaluation, a technique for specializing programs. We describe the modeling methodology at a …

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Personalizing The Gams Cross-Index, Saverio Perugini, Priya Lakshminarayanan, Naren Ramakrishnan Jan 2000

Personalizing The Gams Cross-Index, Saverio Perugini, Priya Lakshminarayanan, Naren Ramakrishnan

Computer Science Faculty Publications

The NIST Guide to Available Mathematical Software (GAMS) system at http://gams.nist .gov serves as the gateway to thousands of scientific codes and modules for numerical computation. We describe the PIPE personalization facility for GAMS, whereby content from the cross-index is specialized for a user desiring software recommendations for a specific problem instance. The key idea is to (i) mine structure, and (ii) exploit it in a programmatic manner to generate personalized web pages. Our approach supports both content-based and collaborative personalization and enables information integration from multiple (and complementary) web resources. We present case studies for the domain of linear, …

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Development Of Object Oriented Components For Atm Network Simulation With Emphasis On Congestion Control, Wen Dee Lee Jan 2000

Development Of Object Oriented Components For Atm Network Simulation With Emphasis On Congestion Control, Wen Dee Lee

Student Works (2000-2009)

Asynchronous Transfer Mode (ATM) provides the required flexibility for the support of heterogeneous services for Broadband Integrated Services Digital Networks (8-ISDN) environment. A TM has proven to be efficient and flexible in handling a wide range of integrated service traffic. The most outstanding feature of ATM is that it provides the Quality of Service (QoS) guarantees between connections. In a network environment, congestion control is an important factor to consider as to guarantee the negotiated QoS. To study, observe and develop the congestion control mechanism in an ATM network, simulation modelling provides the ideal domain. The aim of this project …

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Development Of Object Oriented Components For Atm Network Simulation With Emphasis On Switch Architecture, Meng Kiat Gan Jan 2000

Development Of Object Oriented Components For Atm Network Simulation With Emphasis On Switch Architecture, Meng Kiat Gan

Student Works (2000-2009)

Asynchronous Transfer Mode (ATM) is considered to be the foundation on which B­ISON is to be built. It is the new generation of communication protocol that being deployed throughout the telecommunication industry. An important component of this communication networks is the ATM switch whose basic functions are to direct cells from input port to output port and to buffer cell destined to the same output port from different input port. Understanding an ATM switch before building it, is a challenging task as one must consider the design of switching architecture and cell buffering at the same time. As the switching …

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Cascade Artmap: Integrating Neural Computation And Symbolic Knowledge Processing, Ah-Hwee Tan Mar 1997

Cascade Artmap: Integrating Neural Computation And Symbolic Knowledge Processing, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

This paper introduces a hybrid system termed cascade adaptive resonance theory mapping (ARTMAP) that incorporates symbolic knowledge into neural-network learning and recognition. Cascade ARTMAP, a generalization of fuzzy ARTMAP, represents intermediate attributes and rule cascades of rule-based knowledge explicitly and performs multistep inferencing. A rule insertion algorithm translates if-then symbolic rules into cascade ARTMAP architecture. Besides that initializing networks with prior knowledge can improve predictive accuracy and learning efficiency, the inserted symbolic knowledge can be refined and enhanced by the cascade ARTMAP learning algorithm. By preserving symbolic rule form during learning, the rules extracted from cascade ARTMAP can be compared …

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Inductive Neural Logic Network And The Scm Algorithm, Ah-Hwee Tan, Loo-Nin Teow Feb 1997

Inductive Neural Logic Network And The Scm Algorithm, Ah-Hwee Tan, Loo-Nin Teow

Research Collection School Of Computing and Information Systems

Neural Logic Network (NLN) is a class of neural network models that performs both pattern processing and logical inferencing. This article presents a procedure for NLN to learn multi-dimensional mapping of both binary and analog data. The procedure, known as the Supervised Clustering and Matching (SCM) algorithm, provides a means of inferring inductive knowledge from databases. In contrast to gradient descent error correction methods, pattern mapping is learned by an inductive NLN using fast and incremental clustering of input and output patterns. In addition, learning/encoding only takes place when both the input and output match criteria are satisfied in a …

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Resource/Dataflow Graph Operating System Development, Sriram J. Coimbatore Oct 1996

Resource/Dataflow Graph Operating System Development, Sriram J. Coimbatore

Electrical & Computer Engineering Theses & Dissertations

Implementation of a new dataflow schedule model is the objective of this thesis. The dataflow model algorithm called the resource/dataflow graph model is implemented on a peer-to-peer communication network comprising of six personal computers. This dataflow model is implemented making use of an earlier dataflow model called ATAMM (Algorithm to Architecture Mapping Model) developed by ODU and National Aeronautics and Space Administration (NASA). Development issues include modification of the RDFG testbed operating system and a scheme to transfer data buffers using the ethernet channel from one processor to another processor. This, in turn, equips each sub-module of an application with …

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