ppxscal/embedding_network huggingface dataset:
Expansion of layouts of complete binary trees into grids
Authors: Y.-B. Lin, Z. Miller, M. Perkel, D. Pritikin, I. H. Sudborough
Venue: Discrete Applied Mathematics (2003)

Let Th be the complete binary tree of height h. Let M be the infinite grid graph with vertex set Z2, where two vertices (x1, y1) and (x2, y2) of M are adjacent if and only if |x1-x2| + |y1-y2|= 1. Suppose that T is a tree which is a subdivision of Th and is also isomorphic to a subgraph of M. Motivated by issues in optimal VLSI design, we show that the point expansion ratio n(T)/n(Th) = n(T)/(2h+1 - 1) is bounded below by 1.122 for h sufficiently large. That is, we give bounds on how many vertices of degree 2 must be inserted along the edges of Th in order that the resulting tree can be laid out in the grid. Concerning the constructive end of VLSI design, suppose that T is a tree which is a subdivision of Th and is also isomorphic to a subgraph of the n × n grid graph. Define the expansion ratio of such a layout to be n2/n(Th)=n2/(2h+1 - 1). We show constructively that the minimum possible expansion ratio over all layouts of Th is bounded above by 1.4656 for sufficiently large h. That is, we give efficient layouts of complete binary trees into square grids, making improvements upon the previous work of others. We also give bounds for the point expansion and expansion problems for layouts of Th into extended grids, i.e. grids with added diagonals.
From Web Services to OGSA: Experiences in Implementing an OGSA-based Grid Application
Authors: Radu Prodan, Thomas Fahringer
Venue: Proceedings of the 4th International Workshop on Grid Computing (2003)

In previous work we have presented the ZENTURIO experimentmanagement system for performance and parameterstudies of parallel and distributed applications on clusterand Grid architectures. In this paper we describe experiencesof an on-going work, targeting the implementationof ZENTURIO on top of the Open Grid Services Architecture(OGSA). We analyse the opportunities offered by aWeb services toolkit to develop Grid services as required byOGSA and compare them with the solutions offered by theOpen Grid Services Infrastructure (OGSI) specification. Issuesregarding proxy management, service lifecycle, UDDIservice repository, firewall management, Factory and Registryservices, service throughput, and security are comparativelyanalysed in both implementations.
Performance Analysis and Service Differentiation in IEEE 802.11 WLAN
Authors: Jianhua He, Lin Zheng, Zongkai Yang, Chun Tung Chou
Venue: Proceedings of the 28th Annual IEEE International Conference on Local Computer Networks (2003)

This paper presents an analytical model for saturationthroughput of IEEE 802.11 Distributed Coordination Function(DCF) with multiple classes of service based on varyingthe parameters used in Medium Access Control. Inparticular, we show that relative service differentiation caneasily be achieved by varying the initial contention windowalone. The simulation results show the validity of thismodel.
Simple Estimators for Relational Bayesian Classifiers
Authors: Jennifer Neville, David Jensen, Brian Gallagher
Venue: Proceedings of the Third IEEE International Conference on Data Mining (2003)

In this paper we present the Relational BayesianClassifier (RBC), a modification of the Simple BayesianClassifier (SBC) for relational data. There exist severalBayesian classifiers that learn predictive models ofrelational data, but each uses a different estimationtechnique for modeling heterogeneous sets of attributevalues. The effects of data characteristics on estimationhave not been explored. We consider four simpleestimation techniques and evaluate them on three real-worlddata sets. The estimator that assumes each multisetvalue is independently drawn from the same distribution(INDEPVAL) achieves the best empirical results. Weexamine bias and variance tradeoffs over a range of datasets and show that INDEPVAL's ability to model moremultiset information results in lower bias estimates andcontributes to its superior performance.
Inter and intra media-object QoS provisioning in adaptive formatters
Authors: Rogério Ferreira Rodrigues, Luiz Fernando Gomes Soares
Venue: Proceedings of the 2003 ACM symposium on Document engineering (2003)

The development of hypermedia/multimedia systems requires the implementation of an element, usually known as formatter, which is in charge of receiving the specification of a document (structure, media-object relationships and presentation descriptions) and controlling its presentation. The process of controlling and maintaining the presentation of a hyperdocument with an output of acceptable quality is a QoS orchestration problem, which needs to be treated by formatters in two related levels: the inter media-object and the intra media-object orchestration. This paper aims at discussing the issues associated to QoS provisioning in hypermedia systems, focusing on the design and implementation of formatters. We propose a QoS framework for hypermedia formatters based on a generic quality of service model for communication environments. The paper also comments the experience obtained in the framework instantiation for the HyperProp system formatter.
Object-process methodology applied to modeling credit card transactions
Authors: Dov Dori
Venue: Advanced topics in database research vol. 1 (2003)

Object-Process Methodology (OPM) is a system development and specification approach that combines the major system aspects-function, structure and behavior-within a single graphic and textual model. Having applied OPM in a variety of domains, this chapter specifies an electronic commerce system in a hierarchical manner, at the top of which are the processes of managing a generic product supply chain before and after the product is manufactured. Focusing on the post-product supply chain management, we gradually refine the details of the fundamental, almost "classical" electronic commerce interaction between the retailer and the end-customer, namely payment over the Internet using the customer's credit card. The specification results in a set of Object-Process Diagrams and a corresponding equivalent set of Object-Process Language sentences. The synergy of combining structure and behavior within a single formal model, expressed both graphically and textually, yields a highly expressive system modeling and specification tool. The comprehensive, unambiguous treatment of this basic electronic commerce process is formal, yet intuitive and clear, suggesting that OPM is a prime candidate for becoming a common standard vehicle for defining, specifying, and analyzing electronic commerce and supply chain management systems.
Energy Partitions and Image Segmentation
Authors: Pablo Andrés Arbeláez, Laurent D. Cohen
Venue: Journal of Mathematical Imaging and Vision (2004)

We address the issue of low-level segmentation for real-valued images. The proposed approach relies on the formulation of the problem in terms of an energy partition of the image domain. In this framework, an energy is defined by measuring a pseudo-metric distance to a source point. Thus, the choice of an energy and a set of sources determines a tessellation of the domain. Each energy acts on the image at a different level of analysis&semi; through the study of two types of energies, two stages of the segmentation process are addressed. The first energy considered, the path variation, belongs to the class of energies determined by minimal paths. Its application as a pre-segmentation method is proposed. In the second part, where the energy is induced by a ultrametric, the construction of hierarchical representations of the image is discussed.
Dendrogram seriation using simulated annealing
Authors: Steven A. Morris, Benyam Asnake, Gary G. Yen
Venue: Information Visualization (2003)

Seriation is the ordering of the leaves of a dendrogram, such that leaves representing similar items are placed near each other according to some metric, within the constraints of the cluster tree. Such ordering greatly aids the interpretation of the relations represented by the dendrogram and reduces visual misinterpretation caused by unrelated items from different subtrees being placed near each other during random ordering. The seriation method presented here uses simulated annealing to find an approximately optimal dendrogram ordering by minimizing a penalty function. The method employs a 'similarity weighted distance' penalty function that tends to avoid artifacts introduced by the traveling salesman problem algorithms commonly used for dendrogram seriation. Examples are given showing the effectiveness of the method in presenting dendrograms of the structure of a social network, and additional examples show an application for interpreting the structure of a network of journal papers covering the subject of anthrax research.
On Mesh-Independent Convergence of an Inexact Newton--Multigrid Algorithm
Authors: Peter N. Brown, Panayot S. Vassilevski, Carol S. Woodward
Venue: SIAM Journal on Scientific Computing (2003)

In this paper we revisit and prove optimal-order and mesh-independent convergence of an inexact Newton method where the linear Jacobian systems are solved with multigrid techniques. This convergence is shown using Banach spaces and the norm $\max\{\|\cdot\|_1,\; \|\cdot\|_{0,\infty}\}$, a stronger norm than is used in previous work. These results are valid for a class of second-order, semilinear, finite element, elliptic problems posed on quasi-uniform grids. Numerical results are given which validate the theory.
The Goldilocks problem
Authors: Tudor Hulubei, Eugene C. Freuder, Richard J. Wallace
Venue: Artificial Intelligence for Engineering Design, Analysis and Manufacturing (2003)

Constraint-based reasoning is often used to represent and find solutions to configuration problems. In the field of constraint satisfaction, the major focus has been on finding solutions to difficult problems. However, many real-life configuration problems, although not extremely complicated, have a huge number of solutions, few of which are acceptable from a practical standpoint. In this paper we present a value ordering heuristic for constraint solving that attempts to guide search toward solutions that are acceptable. More specifically, by considering weights that are assigned to values and sets of values, the heuristic can guide search toward solutions for which the total weight is within an acceptable interval. Experiments with random constraint satisfaction problems demonstrate that, when a problem has numerous solutions, the heuristic makes search extremely efficient even when there are relatively few solutions that fall within the interval of acceptable weights. In these cases, an algorithm that is very effective for finding a feasible solution to a given constraint satisfaction problem (the &ldquo;maintained arc consistency&rdquo; algorithm or MAC) does not find a solution in the same weight interval within a reasonable time when it is run without the heuristic.
Link-adaptation and Transmit Power Control for Unicast and Multicast in IEEE 802.11a/h/e WLANs
Authors: António Grilo, Mário Nunes
Venue: Proceedings of the 28th Annual IEEE International Conference on Local Computer Networks (2003)

This paper proposes a mechanism to combine link-adaptationand transmit power control (TPC) in IEEE802.11a WLANs. The link-adaptation and TPCalgorithms try to maximize the goodput of the WLAN,while minimizing transmit power. The algorithm runs atthe sender, but it relies on feedback from the receiver.The latter notifies the sender about the Signal-to-Interference-plus-Noise-Ratio experienced in previous transmissions, allowing a prediction of the channelstatus. An extension of the algorithm for multicast is alsopresented. The implementation of the proposedmechanism in IEEE 802.11a/h/e WLANs is discussed andits performance evaluated.
Robust goal-mouth detection for virtual content insertion
Authors: Kongwah WAN, Xin YAN, Xinguo YU, Changsheng XU
Venue: Proceedings of the eleventh ACM international conference on Multimedia (2003)

In this paper, we describe a working system that detects and segments goal-mouth appearances of soccer video in real-time. Processing on sub-optimal quality images after MPEG-decoding, the system constrains the Hough Transform-based line-mark detection to only the dominant green regions. The vertical goal-posts and horizontal goal-bar are then isolated by color-based region (pole)-growing. We demonstrate its application for quick video browsing and virtual content insertion.
Constructing Space-Time Trellis Codes Using Orthogonal Designs
Authors: Girish Ganesan, Petre Stoica
Venue: Wireless Personal Communications: An International Journal (2004)

In this paper we consider the design of space-time trellis codes using orthogonal designs. We derive a condition on the codewords to obtain the maximum received signal energy and show that the codes based on orthogonal designs satisfy this condition. We consider in detail the design of a trellis code for two transmit antennas. The new code we develop has a higher diversity in fast fading and a higher coding gain in quasi-static fading when compared to other existing space-time codes. We also consider a turbo implementation of the new trellis code which results in very high diversity gains in fast fading channels.
A new quantum claw-finding algorithm for three functions
Authors: Kazuo Iwama, Akinori Kawachi
Venue: New Generation Computing (2003)

For k functions f1,...,fk, a k-tuple (x1,...,xk) such that f1(x1) = ... = fk(xk) is called a claw of f1,...,fk. In this paper, we construct a new quantum claw-finding algorithm for three functions that is efficient when the number M of intermediate solutions is small. The known quantum claw-finding algorithm for three functions requires O(N7/8 log N) queries to find a claw, but our algorithm requires O(N3/4 log N) queries if M ≤ √N and O(N7/12M1/3 log N) queries otherwise. Thus, our algorithm is more efficient if M ≤ N7/8.
Knowledge reuse in an application service provider
Authors: Greg Timbrell, Karen J. Nelson, Tony J. Jewels
Venue: Knowledge management: current issues and challenges (2003)

This qualitative study of support personnel in an Enterprise Systems Application Service Provider assesses and confirms Markus' Theory of Knowledge Reuse. Following disappointing knowledge capture outcomes during implementation and the consequential inability to reuse that knowledge effectively, enterprise systems applications support managers are recognizing the importance of lifecycle knowledge management as they face the first major upgrade of their clients' enterprise systems. This study also explores the dominant knowledge reuse types of support personnel. We extend Markus' typology to include Primary Data Miner to explain management's dominant knowledge reuse situations.
Characterization of the Burst Stabilization Protocol for the RR/RR CICQ Switch
Authors: Neil J. Gunther, Kenneth J. Christensen, Kenji Yoshigoe
Venue: Proceedings of the 28th Annual IEEE International Conference on Local Computer Networks (2003)

Input buffered switches with Virtual Output Queueing(VOQ) can be unstable when presented with unbalancedloads. Existing scheduling algorithms, including iSLIPfor Input Queued (IQ) switches and Round Robin (RR)for Combined Input and Crossbar Queued (CICQ)switches, exhibit instability for some schedulable loads.We investigate the use of a queue length threshold andbursting mechanism to achieve stability without requiringinternal speed-up. An analytical model is developed toprove that the burst stabilization protocol achievesstability and to predict the minimum burst value neededas a function of offered load. The analytical model isshown to have very good agreement with simulationresults. These results show the advantage of the RR/RRCICQ switch as a contender for the next generation ofhigh-speed switches.
Constrained Floorplanning with Whitespace
Authors: Yan Feng, Dinesh Mehta
Venue: Proceedings of the 17th International Conference on VLSI Design (2004)

This paper considers the constrained floorplanningproblem in the context of a design scenario where floorplansare required to contain some white space to facilitatesubsequent buffer insertion. An elegant bounded iterativemethodology for floorplan-refinement based on themin-cost max-flow formulation of Feng et al [1] augmentedby a heuristic area-redistribution algorithm ispresented. This approach results in substantially bet-terquality floorplans than previously reported as substantiatedby our experimental results.
Web services as the foundation for learning complex software system development
Authors: Marty Humphrey
Venue: ACM SIGCSE Bulletin (2004)

A significant challenge for Computer Science departments is how best to get new graduate students involved with their chosen research projects. Ideally, the incoming graduate students will as a whole have both a solid understanding of computing principles behind large-scale software development and a broad "skill set", e.g., for conducting systems-oriented research. This rarely occurs, due to the diversity of backgrounds of incoming students--even the most qualified applicant can have deficiencies. To address this problem, we have developed a first-year graduate course that balances and integrates practical considerations with basic principles of complex software system development. To make the discussions of designing, implementing, and evaluating complex software systems more concrete, we situate the core of the class in the context of Web Services. We are currently teaching this class for the second time, and, while there will always be open issues given the nature and scope of this class, we have received positive feedback from the students and the other members of the department. Students recognize the practicality of Web Services. Students also appreciate the research possibilities that arise while evaluating the state of the art with regard to Web Services.
Inductively Verifying Invariant Properties of Parameterized Systems
Authors: Abhik Roychoudhury, I. V. Ramakrishnan
Venue: Automated Software Engineering (2004)

Verification of distributed algorithms can be naturally cast as verifying parameterized systems, the parameter being the number of processes. In general, a parameterized concurrent system represents an infinite family (of finite state systems) parameterized by a recursively defined type such as chains, trees. It is therefore natural to verify parameterized systems by inducting over this type. However, construction of such proofs require combination of model checking with deductive capability. In this paper, we develop a logic program transformation based proof methodology which achieves this combination. One of our transformations (unfolding) represents a single resolution step. Thus model checking can be achieved by repeated application of unfolding. Other transformations (such as folding) represent deductive reasoning and help recognize the induction hypothesis in an inductive proof. Moreover the unfolding and folding transformations can be arbitrarily interleaved in a proof, resulting in a tight integration of decision procedures (such as model checking) with deductive verification.Based on this technique, we have designed and implemented an invariant prover for parameterized systems. Our proof technique is geared to automate nested induction proofs which do not involve strengthening of induction hypothesis. The prover has been used to automatically verify invariant properties of parameterized cache coherence protocols, including broadcast protocols and protocols with global conditions. Furthermore, we have employed the prover for automatic verification of mutual exclusion in the Java Meta-Locking Algorithm. Meta-Locking is a distributed algorithm developed recently by designers in Sun Microsystems for ensuring secure access of Java objects by an arbitrary number of Java threads.
Answering imprecise database queries: a novel approach
Authors: Ullas Nambiar, Subbarao Kambhampati
Venue: Proceedings of the 5th ACM international workshop on Web information and data management (2003)

A growing number of databases especially those published on the Web are becoming available to external users. Users of these databases are provided simple form-based query interfaces that hide the underlying schematic details. Constrained by the expressiveness of the query interface users often have difficulty in articulating a precise query over the database. Supporting imprecise queries over such systems would allow users to quickly find relevant answers without iteratively refining their queries. For databases to support imprecise queries they must provide answers that closely match the query constraints. In this paper we focus on answering imprecise user queries without changing the existing database system. We propose to support imprecise queries over a database by identifying a set of related precise queries that provide answers that are relevant to the user given query. We present a domain independent approach based on information retrieval techniques to estimate the distance between queries. To demonstrate the utility and usefulness of our approach we perform usability tests and provide results.
MinSQL: a simple componentized database for the classroom
Authors: Garret Swart
Venue: Proceedings of the 2nd international conference on Principles and practice of programming in Java (2003)

MinSQL is a Java relational database that has been optimised for use in the advanced undergraduate or graduate school classroom. It builds on basic Java technology and design patterns both to help the students get a better understanding of Java technology and patterns and also to allow students to quickly understand the database implementation. The MinSQL design is embodied in a set of Java interfaces that are implemented by a set of components and allow for a wide variety of implementations. The base implementation is designed to be simple but suitable as a base for students to extend or reimplement as part of classroom projects.
Estimation of the plastic volume fraction from a linear-elastic finite element analysis
Authors: A. C. A. Ramsay
Venue: Finite Elements in Analysis and Design (2003)

The plastic volume fraction is one of a range of parameters used in the design of rotating components that are subjected to an overspeeding cycle as part of the manufacturing process. Overspeeding is carried out in order to impart favourable residual compressive stresses and thereby improve the component's fatigue life. However, the amount of material that becomes plastic during overspeeding needs to be controlled carefully if pre-machined manufacturing tolerances are to be maintained. The plastic volume fraction expresses the volume of material in which yield has occurred as a fraction of the total volume, the actual value of which may only be determined through non-linear plastic analysis. The complexity and associated cost of such analyses are of such a level that a linear-elastic approximation to the plastic volume fraction is often used in lieu of the exact quantity. This paper presents a scheme for estimating the plastic volume fraction as a post-processing operation conducted on the results of a three-dimensional linear-elastic finite element analysis. The performance of the scheme is evaluated through numerical examples using element types typically found in commercial finite element codes. In addition to considering how the scheme is able to approximate the linear-elastic plastic volume fraction, plastic analysis is used to illustrate the way in which this quantity approximates the actual plastic volume fraction. The paper concludes with the analysis of a centrifugal impeller; a component drawn from the author's own field of interest. This analysis enables the various strands of the paper to be brought together and provides an example through which it is possible to discuss suitable limiting values for the plastic volume fraction. The examples indicate a plastic volume fraction of 0.05 to be a reasonable limiting value for the linear-elastic approximation adopted in this paper.