ppxscal/embedding_network huggingface dataset:
Fitting points on the real line and its application to RH mapping
Authors: Johan Håstad, Lars Ivansson, Jens Lagergren
Venue: Journal of Algorithms (2003)

A natural problem is that of, given an n × n symmetric matrix D, finding an arrangement of n points on the real line such that the so obtained distances agree as well as possible with the by D specified distances. We refer to the variation in which the difference in distance is measured in maximum norm as the MATRIX-TO-LINE problem. The MATRIX-TO-LINE problem has previously been shown to be NP-complete [J.B. Saxe, 17th Allerton Conference in Communication, Control, and Computing, 1979, pp. 480-489]. We show that it can be approximated within 2, but unless P = NP not within 7/5 - δ for any δ > 0. We also show a tight lower bound under a stronger assumption. We show that the MATRIX-TO-LINE problem cannot be approximated within 2 - δ unless 3-colorable graphs can be colored with ⌈4/δ⌉ colors in polynomial time. Currently, the best polynomial time algorithm colors a 3-colorable graph with Õ(n3/14) colors [A. Blum, D. Karger, Inform. Process. Lett. 61 (1), (1997), 49-53]. We apply our MATRIX-TO-LINE algorithm to a problem in computational biology, namely, the Radiation Hybrid (RH) problem. That is, the algorithmic part of a physical mapping method called RH mapping. This gives us the first algorithm with a guaranteed convergence for the general RH problem.
Graph-based anomaly detection
Authors: Caleb C. Noble, Diane J. Cook
Venue: Proceedings of the ninth ACM SIGKDD international conference on Knowledge discovery and data mining (2003)

Anomaly detection is an area that has received much attention in recent years. It has a wide variety of applications, including fraud detection and network intrusion detection. A good deal of research has been performed in this area, often using strings or attribute-value data as the medium from which anomalies are to be extracted. Little work, however, has focused on anomaly detection in graph-based data. In this paper, we introduce two techniques for graph-based anomaly detection. In addition, we introduce a new method for calculating the regularity of a graph, with applications to anomaly detection. We hypothesize that these methods will prove useful both for finding anomalies, and for determining the likelihood of successful anomaly detection within graph-based data. We provide experimental results using both real-world network intrusion data and artificially-created data.
Long-wavelength nitride lasers on GaAs
Authors: M. Pessa, C. S. Peng, T. Jouhti, E.-M. Pavelescu, W. Li, S. Karirinne, H. Liu, O. Okhotnikov
Venue: Microelectronic Engineering (2003)

This paper reviews recent studies of structural and optical properties of long wavelength GaInNAs/GaAs quantum well semiconductors and the performance features of GaInNAs/GaAs vertical cavity surface emitting lasers (VCSELs) and edge-emitting lasers. The studies forecast that GaInNAs VCSELs and possibly edge-emitting lasers will become a compliment, or even a replacement, to the now dominant InP-based devices at 1.3-µm short-haul data transmission systems, but whether GaInNAs lasers in general will ever be competitive with the InP lasers at 1.4-1.6 µm is an entirely open issue today. The dilute nitride technology has still some distance to go in addressing its remaining concerns; yet, the authors believe that it is still the best bet to bring about the long-waited breakthrough in the component technology for optical fibre networks.
On the structure of connected locally GQ(3, 9)-graphs
Authors: A. A. Makhnev, D. V. Paduchikh
Venue: Discrete Applied Mathematics (2004)

If F is a class of graphs then a graph Γ is called a locally F-graph, provided that the neighborhood of every vertex of Γ belongs to F. Let GQ(s,t) denote the point graph of a generalized quadrangle of order (s,t). We prove that every connected locally GQ(3,9)-graph is isomorphic to the McLaughlin graph.
Symbolic Place Recognition in Voronoi-Based Maps by Using Hidden Markov Models
Authors: B. L. Boada, D. Blanco, L. Moreno
Venue: Journal of Intelligent and Robotic Systems (2004)

This article presents a new algorithm to recognize natural distinctive places such as corridors, halls, narrowings, corridors with doors opening on the left side, etc., from indoor environments using Hidden Markov Models (HMM). HMM give a stochastic solution which can be used to make decisions on localization, navigation and path-planning. The environment is modeled as a topo-geometric map which combines topological and geometric information. This map is obtained from a Voronoi diagram using measurements of a laser telemeter. The characteristics of topo-geometric map (nodes, number of edges adjacent to nodes, slope of edges, etc.) are used to learn and to recognize the different places typical of indoor environments. This map can be used in order to resolve several problems in robotics such as localization, navigation and path-planning. Our method of place recognition is a fast and effective way for a robot to recognize typical places of indoor environments from a topo-geometric map.
Building Trustworthy Systems: Guided State Estimation as a Feasible Approach for Interpretation, Decision and Action Based on Sensor Data
Authors: John James, Frank Mabry
Venue: Proceedings of the Proceedings of the 37th Annual Hawaii International Conference on System Sciences (HICSS'04) - Track 2 - Volume 2 (2004)

Sensor management plays a key role in control of critical infrastructure systems. This paper describes an approach for improving capabilities for interpretation, decision, and action based on sensor data through application of an intermediate level of aggregation. Improvements in complex system understanding are needed now at the interface between human understanding of system state and machine understanding of system state. The human understanding of the state of the system (situation understanding) must be achieved under ever more demanding time constraints. As expectations increase for faster, more-informed (better) decisions by humans at the supervisory-control level, improvements are needed forproviding support for interpreting sensor data to understand current system behaviors and make informed human decisions on actions needed to cause future system behaviors to comply with some planned sequence of events or patterns of behavior. Likewise, as the number and capabilities of networked sensors increase, improvements are needed in enabling autonomous control systems at local levels to understand current system behaviors and makeinformed machine decisions on actions needed to cause future system behaviors to comply with some planned sequence of events or patterns of behavior. The paper discusses achieving an intermediate level of aggregation: (1) as a scientific basis for understanding complex system behaviors, (2) as an effective tool for creation of technologies based an intermediate level of aggregation and (3) as a basis for education of leaders who must make decisions based on understanding of the current system state.
Handover and Uplink Power Control Performance in the 3.84 Mcps TDD mode of UTRA Network
Authors: Janne Kurjenniemi, Seppo Hämäläinen, Tapani Ristaniemi
Venue: Wireless Personal Communications: An International Journal (2003)

In this article we consider the performance of the 3.84 Mcps time-division duplex (TDD) mode of UTRA (Universal Terrestrial Radio Access) network. We emphasize two of the radio resource management algorithms, handover and uplink power control, whose role in the overall system performance is studied extensively. First, a handover algorithm used in WCDMA (Wideband Code Division Multiple Access) standard is considered in a TDD-mode operation. This gives rise to a careful setting of different handover parameters, and the evaluation of the effects to the system performance. Secondly, the specified uplink power control algorithm is considered. Since it is based on several user-made measurements which may involve both random and systematic errors a careful study about the suitability of the power control scheme is carried out.
SPIN: A Toolkit for Distributed Scientific Computing
Authors: Martha González
Venue: Proceedings of the XXIII International Conference of the Chilean Computer Science Society (2003)

The aim of this paper is to present SPIN, an interactiveand integrated software environment for scientific computation.The main goal of SPIN is to allow the access to remotecomputational and storage resources in an easy to use andtransparent way from the user's point of view. This environment,based on a multi-tier architecture, has been developedfollowing a state of the art software engineering processwhich incorporates the CORBA standard (Common ObjectRequest Broker Architecture) the PAC-Amodeus model, (amulti-agent based model for interactive systems architecture)and the Unified Process (UP) to guide the whole life-cycleof the project.
Variations in Software Development Practices
Authors: Capers Jones
Venue: IEEE Software (2003)

Thousands of companies develop software. In the past 35 years, over a million software applications have been put into use and more are being developed every day. But the methods and personnel used to develop software vary enormously. The application's size and type are two key factors that determine what development methods will likely be used and what kinds of specialists will be employed. Building larger software projects is much more complex than building small programs, requiring many kinds of specialists and development activities.
A multimedia real-time conferencing system: architecture and implementation
Authors: L. Lamont, G. Henderson, N. D. Georganas
Venue: Proceedings of the 1993 conference of the Centre for Advanced Studies on Collaborative research: software engineering - Volume 1 (1993)

In this paper, we describe a distributed real-time multimedia conferencing system architecture and implementation. The architecture provides a framework for allowing two or more users to communicate and exchange information and to simultaneously manipulate multimedia documents. It supports a variety of Computer Supported Collaborative Work applications and can be configured to cover diverse geographical distributions such as Local Area Networks interconnected through Metropolitan and Wide Area Networks. We also describe the implementation of a group-oriented multimedia conferencing system based on this architecture. This prototype, developed in the Multimedia Communications Research Laboratory (MCRLab) at the University of Ottawa, implements a joint text editing application within a multimedia conferencing system and employs a locking mechanism for concurrency control. The prototype has been implemented using TCP/IP on 386 computers running the UNIX operating system. The user interface has been developed using the Andrew User Interface System, an object-oriented multimedia user interface development system. Finally, new research based on the architecture and prototype is outlined. We have begun to investigate connection-oriented networks which will allow for the integration of audio and video into the architecture. We are also exploring methods to integrate distributed synchronization control algorithms into the model.
Virtualized network storage
Authors: Darrell C. Anderson
Venue:  (2002)

This dissertation explores virtualized network storage, adapting the principles from scalable system-area network (SAN) storage to the IP-based client/server network attached storage (NAS) environment. Unlike SAN storage, which exports a simple low-level block access protocol, NAS uses a much richer, high-level file system interface. A key challenge for NAS addressed by this work is to aggregate a pool of high-level storage into a scalable, unified virtual resource. Furthermore, this virtualized storage must be &ldquo;client agnostic,&rdquo; compatible with standard clients at the network file service protocol level. This work combines ideas in virtualization, service decomposition, fault tolerance, and scalable systems design to create a successful, novel network storage architecture. The prototype, called Slice, factors out the traditional client layer into a lightweight network-level request switching filter. This interposed request routing architecture enables incremental construction of powerful distributed storage services while preserving compatibility with standard file system clients.
Transition and cancellation in concurrency and branching time
Authors: Vaughan R. Pratt
Venue: Mathematical Structures in Computer Science (2003)

We review the conceptual development of (true) concurrency and branching time starting from Petri nets and proceeding via Mazurkiewicz traces, pomsets, bisimulation, and event structures up to higher dimensional automata (HDAs), whose acyclic case may be identified with triadic event structures and triadic Chu spaces. Acyclic HDAs may be understood as extending the two truth values of Boolean logic with a third value $\T$ expressing transition. We prove the necessity of such a third value under mild assumptions about the nature of observable events, and show that the expansion of any complete Boolean basis $L$ to $L_{\T}$ with a third literal $\that a$ expressing $a=\T$ forms an expressively complete basis for the representation of acyclic HDAs. The main contribution is a new value $\cancel$ of cancellation, which is a sibling of $\T$, serving to distinguish $a(b+c)$ from $ab+ac$ while simplifying the extensional definitions of termination $\tick\A$ and sequence $\A\B$. We show that every HDAX (acyclic HDA with $\cancel$) is representable in the expansion of $L_{\T}$ to $L_{\T\cancel}$ with a fourth literal $\can a$ expressing $a=\cancel$.
GMDH-Type neural network modelling of explosive cutting process of plates using singular value decomposition
Authors: A. Darvizeh, N. Nariman-Zadeh, H. Gharababaei
Venue: Systems Analysis Modelling Simulation (2003)

GMDH-type neural networks are used for modelling and prediction of explosive cutting process of plates by shaped charges. The aim of such modelling is to show how the depth of penetration varies with the variation of important parameters. It is also demonstrated that singular value decomposition (SVD) can be effectively used to find the vector of coefficients of a quadratic sub-expression embodied in such GMDH-type networks. Such application of SVD will highly improve the performance of GMDH-type networks to model the very complex process of explosive cutting of plates by shaped charges.
Reliability bounds improvement via cut set or path set rearrangements
Authors: S. Tsitmidelis, M. V. Koutras, V. Zissimopoulos
Venue: Proceedings of the international conference on Computational methods in sciences and engineering (2003)

The present article deals with the development of a systematic procedure for improving the general reliability bounds published recently by Fu and Koutras (1995). Koutras, Tsitmidelis and Zissimopoulos (2003) proved that, for a given permutation of the cut sets or path sets of a coherent structure, the identification of the optimal bounds can be achieved by transforming the set-theoretic and probabilistic conditions associated with them to an equivalent Set Covering Problem. As a consequence, genetic algorithms established for the Set Covering Problem were brought into play to derive very tough approximation intervals for a general system's reliability at very competitive computer times.The object of the present work is to investigate procedures for spotting out rearrangements of the family of cut sets or path sets which yield high quality reliability bounds. The main tool exploited to achieve that, is a Traveling Salesman Problem based model combined with certain efficient techniques that facilitate the transition between the bounds associated with different rearrangements. Numerical experimentation is carried out to assess the power of the suggested approach and finally, a brief discussion for future research in this framework is included.
Regression Test Selection Based on Version Changes of Components
Authors: A. S. M. Sajeev, Bugi Wibowo
Venue: Proceedings of the Tenth Asia-Pacific Software Engineering Conference Software Engineering Conference (2003)

In component-based systems, regression test selectionis a challenge since vendors of commercial-off-the-shelf(COTS) components do not release source code.In thispaper we model the regression test selection ofcomponent based software systems using UML andObject-Constraint Language.Our model selects test casesbased on version information that can be made availablewith components without the need for accessing sourcecode.
Observe-mine-adopt (OMA): an agile way to enhance software maintainability
Authors: Jane Huffman Hayes, Naresh Mohamed, Tina Hong Gao
Venue: Journal of Software Maintenance: Research and Practice (2003)

We introduce the observe-mine-adopt (OMA) paradigm that assists organizations in making improvements to their software development processes without committing to and undertaking large-scale sweeping organizational process improvement. Specifically, the approach has been applied to improve software practices focused on maintainability. This novel approach is based on the theory that software teams naturally make observations about things that do or do not work well. Teams then mine their artifacts and their recollections of events to find the software products, processes, metrics, etc. that led to the observation. In the case of software maintainability, it is then necessary to perform some measurement to ensure that the methods result in improved maintainability. We introduce two maintainability measures, maintainability product and perceived maintainability, to address this need. Other maintainability measures that may be used in the mine step are also examined. Finally, if the mining activities lead to validated discoveries of processes, techniques or practices that improve the software product, they are formalized and adopted by the team. OMA has been studied experimentally using two project studies and a Web-based health care system which is maintained by a large industrial software organization.
A classification and constraint-based framework for configuration
Authors: Daniel Mailharro
Venue: Artificial Intelligence for Engineering Design, Analysis and Manufacturing (1998)

One of the main difficulties with configuration problem solving lies in the representation of the domain knowledge because many different aspects, such as taxonomy, topology, constraints, resource balancing, component generation, etc., have to be captured in a single model. This model must be expressive, declarative, and structured enough to be easy to maintain and to be easily used by many different kind of reasoning algorithms. This paper presents a new framework where a configuration problem is considered both as a classification problem and as a constraint satisfaction problem (CSP). Our approach deeply blends concepts from the CSP and object-oriented paradigms to adopt the strengths of both. We expose how we have integrated taxonomic reasoning in the constraint programming schema. We also introduce new constrained variables with nonfinite domains to deal with the fact that the set of components is previously unknown and is constructed during the search for solution. Our work strongly focuses on the representation and the structuring of the domain knowledge, because the most common drawback of previous works is the difficulty to maintain the knowledge base that is due to a lack of structure and expressiveness of the knowledge representation model. The main contribution of our work is to provide an object-oriented model completely integrated in the CSP schema, with inheritance and classification mechanisms, and with specific arc consistency algorithms.
Dependence, correlation and Gaussianity in independent component analysis
Authors: Jean-François Cardoso
Venue: The Journal of Machine Learning Research (2003)

Independent component analysis (ICA) is the decomposition of a random vector in linear components which are "as independent as possible." Here, "independence" should be understood in its strong statistical sense: it goes beyond (second-order) decorrelation and thus involves the non-Gaussianity of the data.The ideal measure of independence is the "mutual information" and is known to be related to the entropy of the components when the search for components is restricted to uncorrelated components.This paper explores the connections between mutual information, entropy and non-Gaussianity in a larger framework, without resorting to a somewhat arbitrary decorrelation constraint. A key result is that the mutual information can be decomposed, under linear transforms, as the sum of two terms: one term expressing the decorrelation of the components and one expressing their non-Gaussianity.Our results extend the previous understanding of these connections and explain them in the light of information geometry. We also describe the "local geometry" of ICA by re-expressing all our results via a Gram-Charlier expansion by which all quantities of interest are obtained in terms of cumulants.
Virtual enterprise access control requirements
Authors: M. Coetzee, Jan H. P. Eloff
Venue: Proceedings of the 2003 annual research conference of the South African institute of computer scientists and information technologists on Enablement through technology (2003)

Current developments in IT point towards the formation of loosely coupled enterprises, often referred to as virtual enterprises. These enterprises require both secure and flexible collaboration between unrelated information systems. Web services technology can be used as an ideal platform for realising virtual enterprises throughh their ease of integration, flexibility, and support of XML vocabularies. To ensure the successful implementation of Web services within virtual enterprises, new approaches to security are required. Together with authentication, access control has been seen as a pillar of IT security approaches. The focus of this paper will be to determine requirements that could play a role when the access control policies of such enterprises are defined.
Infrastructure Support for Mobile Collaboration
Authors: Radu Litiu, Amgad Zeitoun
Venue: Proceedings of the Proceedings of the 37th Annual Hawaii International Conference on System Sciences (HICSS'04) - Track 1 - Volume 1 (2004)

Future groupware systems will need to extend collaboration beyond the desktop. They will need to support computing devices with a wide range of capabilities, varying network connectivity, and increasing mobility of users. We have designed and implemented a component-based framework for building reconfigurable distributed applications that addressthe specific needs of mobile environments. This paper focuses on the use of this framework to support mobile collaboration. Components of a groupware application can move across heterogeneous devices while maintaining persistent logical connectivity with groupware services and other users, even during transient network failures. Users do not see any interruptions in the services accessed, and they do not need to manually re-establish connections with the communication parties. New collaboration features can be more easily implemented. For instance, users may "park" their client agents temporarily at a fixed host while they are disconnected. The parked agent can continue to maintain connectivity with other group members on behalf of the user, if desired. We show how this framework can be used to structure distributed applications that adapt their behavior and their interface to the context in which they execute. We give examples of groupware applications we have implemented.