ppxscal/embedding_network huggingface dataset:
On the Circuit Cover Problem for Mixed Graphs
Authors: Orlando Lee, Yoshiko Wakabayashi
Venue: Combinatorics, Probability and Computing (2002)

The circuit cover problem for mixed graphs (those containing edges and&#x002F;or arcs) is defined as follows. Given a mixed graph M with a nonnegative integer weight function p on its edges and arcs, decide whether (M, p) has a circuit cover, that is, a list of circuits in M such that every edge (arc) e is contained in exactly p(e) circuits of the list. In the special case when M is a directed graph (contains only arcs), the problem is easy, but when M is an undirected graph not many results are known. For general mixed graphs this problem was shown to be NP-complete by Arkin and Papadimitriou in 1986. We prove that this problem remains NP-complete for planar mixed graphs. Furthermore, we present a good characterization for the existence of a circuit cover when M is series-parallel (a similar result holds for the fractional version). We also describe a polynomial algorithm to find such a circuit cover, when it exists. This is an ellipsoid-based algorithm whose separation problem is the minimum circuit problem on series-parallel mixed graphs, which we show to be polynomially solvable. Results on two well-known combinatorial problems, the problem of detecting negative circuits and the problem of finding shortest paths, are also presented. We prove that both problems are NP-hard for planar mixed graphs.
Learning and inference in the brain
Authors: Karl Friston
Venue: Neural Networks (2003)

This article is about how the brain data mines its sensory inputs. There are several architectural principles of functional brain anatomy that have emerged from careful anatomic and physiologic studies over the past century. These principles are considered in the light of representational learning to see if they could have been predicted a priori on the basis of purely theoretical considerations. We first review the organisation of hierarchical sensory cortices, paying special attention to the distinction between forward and backward connections. We then review various approaches to representational learning as special cases of generative models, starting with supervised learning and ending with learning based upon empirical Bayes. The latter predicts many features, such as a hierarchical cortical system, prevalent top-down backward influences and functional asymmetries between forward and backward connections that are seen in the real brain.The key points made in this article are: (i) hierarchical generative models enable the learning of empirical priors and eschew prior assumptions about the causes of sensory input that are inherent in non-hierarchical models. These assumptions are necessary for learning schemes based on information theory and efficient or sparse coding, but are not necessary in a hierarchical context. Critically, the anatomical infrastructure that may implement generative models in the brain is hierarchical. Furthermore, learning based on empirical Bayes can proceed in a biologically plausible way. (ii) The second point is that backward connections are essential if the processes generating inputs cannot be inverted, or the inversion cannot be parameterised. Because these processes involve many-to-one mappings, are non-linear and dynamic in nature, they are generally non-invertible. This enforces an explicit parameterisation of generative models (i.e. backward connections) to afford recognition and suggests that forward architectures, on their own, are not sufficient for perception. (iii) Finally, non-linearities in generative models, mediated by backward connections, require these connections to be modulatory, so that representations in higher cortical levels can interact to predict responses in lower levels. This is important in relation to functional asymmetries in forward and backward connections that have been demonstrated empirically.
A look at the economics of open source
Authors: Robert L. Glass
Venue: Communications of the ACM (2004)

Is open source the future of the software field or a passing fad?
On the Edge Distribution of a Graph
Authors: V. Nikiforov
Venue: Combinatorics, Probability and Computing (2001)

We investigate a graph function which is related to the local density, the maximal cut and the least eigenvalue of a graph. In particular it enables us to prove the following assertions.Let p &ge; 3 be an integer, c &isin; (0, 1&#x002F;2) and G be a Kp-free graph on n vertices with e &le; cn2 edges. There exists a positive constant &alpha; = &alpha; (c, p) such that:(a) some &lfloor;n&#x002F;2&rfloor;-subset of V (G) induces at most (c-4 &minus; &alpha;) n2 edges (this answers a question of Paul Erd&ouml;s);(b) G can be made bipartite by the omission of at most (c-2 &minus; &alpha;) n2 edges.
A predictive location model for location-based services
Authors: Hassan A. Karimi, Xiong Liu
Venue: Proceedings of the 11th ACM international symposium on Advances in geographic information systems (2003)

Location-Based Services (LBSs) utilize information about users' locations through location-aware mobile devices to provide services, such as nearest features of interest, they request. This is a common strategy in LBSs and although it is needed and benefits the users, there are additional benefits when future locations (e.g., locations at later times) are predicted. One major advantage of location prediction is that it provides LBSs with extended resources, mainly time, to improve system reliability which in return increases the users' confidence and the demand for LBSs. However, much of the current location prediction research is focused on generalized location models, where the geographic extent is divided into regular-shape cells. These models are not suitable for certain LBSs whose objective is to compute and present on-road services, because a cell may contain several roads while the computation and delivery of a service may require the exact road on which the user is driving. We propose a new model, called Predictive Location Model (PLM), to predict locations in LBSs with road-level granularities. The premise of PLM is geometrical and topological techniques allowing users to receive timely and desired services.
Optimal satisfiability for propositional calculi and constraint satisfaction problems
Authors: Steffen Reith, Heribert Vollmer
Venue: Information and Computation (2003)

We consider the problems of finding the lexicographically minimal (or maximal) satisfying assignment of propositional formulas for different restricted classes of formulas. It turns out that for each class from our framework, these problems are either polynomial time solvable or complete for OptP. We also consider the problem of deciding if in the optimal assignment the largest variable gets value 1. We show that this problem is either in P or PNP complete.
Forms/3: A first-order visual language to explore the boundaries of the spreadsheet paradigm
Authors: Margaret Burnett, John Atwood, Rebecca Walpole Djang, James Reichwein, Herkimer Gottfried, Sherry Yang
Venue: Journal of Functional Programming (2001)

Although detractors of functional programming sometimes claim that functional programming is too difficult or counter-intuitive for most programmers to understand and use, evidence to the contrary can be found by looking at the popularity of spreadsheets. The spreadsheet paradigm, a first-order subset of the functional programming paradigm, has found wide acceptance among both programmers and end users. Still, there are many limitations with most spreadsheet systems. In this paper, we discuss language features that eliminate several of these limitations without deviating from the first-order, declarative evaluation model. The language used to illustrate these features is a research language called Forms&#002F;3. Using Forms&#002F;3, we show that procedural abstraction, data abstraction and graphics output can be supported in the spreadsheet paradigm. We show that, with the addition of a simple model of time, animated output and GUI I&#002F;O also become viable. To demonstrate generality, we also present an animated Turing machine simulator programmed using these features. Throughout the paper, we combine our discussion of the programming language characteristics with how the language features prototyped in Forms&#002F;3 relate to what is known about human effectiveness in programming.
Managing organizational hypermedia documents: a meta-information system
Authors: Woojong Suh, Heeseok Lee
Venue: Advanced topics in database research vol. 1 (2003)

Recently, many organizations have attempted to build hypermedia systems to expand their working areas into Internet-based virtual work places. Increasingly, it becomes more important than ever to manage organizational hypermedia documents (OHDs); metadata plays a critical role for managing these documents. This chapter redefines metadata roles and proposes a metadata classification and the corresponding metadata schema for OHDs. Furthermore, a meta-information system, HyDoMiS (Hyperdocument Meta-information System) built on the basis of this schema is proposed. HyDoMiS performs three functions: metadata management, search, and reporting. The metadata management function is concerned with workflow, documents, and databases. The system is more likely to help implement and maintain hypermedia information systems effectively.
Designing an interface usable by people with dementia
Authors: Norman Alm, Richard Dye, Gary Gowans, Jim Campbell, Arlene Astell, Maggie Ellis
Venue: Proceedings of the 2003 conference on Universal usability (2003)

Caring for people with dementia will be one of the major challenges of the 21st century. Advancing technology may offer ways to augment and supplement human care, if it is sensitively designed with the needs of potential users always taken into account. Developing an interface that a person with dementia can make sense of and use is a difficult goal. Beginning to meet this challenge is one aspect of a programme we have embarked on to develop a multi-media system that can be used to help people with dementia communicate better with others. Reminiscence work with people with dementia is a valuable tool for enabling them to participate meaningfully in conversations. We are developing a system which uses multimedia technology as an effective vehicle for delivering reminiscence stimulus and thus conversation support for people with dementia.
Generation and Verification of Tests for Analog Circuits Subject to Process Parameter Deviations
Authors: S. J. Spinks, C. D. Chalk, I. M. Bell, M. Zwolinski
Venue: Journal of Electronic Testing: Theory and Applications (2004)

The paper presents a test stimulus generation and fault simulation methodology for the detection of catastrophic faults in analog circuits. The test methodology chosen for evaluation is RMS AC supply current monitoring. Tests are generated and evaluated taking account of the potential fault masking effects of process spread on the faulty circuit responses. A new test effectiveness metric of probability of detection is defined and the application of the technique to an analog multiplier circuit is presented. The fault coverage figures are therefore more meaningful than those obtained with a fixed threshold.
Using design fragments to modularize the design of communications in concurrent systems
Authors: Joanne L. Boyd, Gerald M. Karam
Venue: Proceedings of the 7th international workshop on Software specification and design (1993)

This paper introduces design fragments as a fundamental component of a design process for strong traceability in the design of concurrent systems. Design fragments represent reusable alternatives for the independent design of the communication requirements in a concurrent system. They are defined with formal relations to segments of communicating state machines, and are applied such that they satisfy the semantics of the communications defined by the specification. This paper introduces the concept of design fragments, the approach to developing and using them, along with an illustrative example.
Simulation in environmental and ecological systems
Authors: Lee A. Belfore,  II
Venue: Applied system simulation: methodologies and applications (2003)

Computer simulation continues to be an important tool in understanding and managing environmental and ecological systems. Simulation provides a virtual laboratory within which scenarios can be evaluated and theories can be tested. Some basic principles of simulation, numeral methods, and validation relevant to the simulation domain of interest are reviewed. Several aspects of ecological system simulation are discussed including a focus on population ecology. Several topics in environmental system simulation are covered including a general introduction to modeling and a discussion of climate, plume, and noise modeling. Finally, a discussion on visualization of environmental and ecological systems is presented.
Computing a matrix function for exponential integrators
Authors: Ya Yan Lu
Venue: Journal of Computational and Applied Mathematics (2003)

An efficient numerical method is developed for evaluating ϕ(A), where A is a symmetric matrix and ϕ is the function defined by ϕ(x)= (ex - 1)/x = 1 +x/2 + x2/6 +.... This matrix function is useful in the so-called exponential integrators for differential equations. In particular, it is related to the exact solution of the ODE system dy/dt =Ay + b, where A and b are t-independent. Our method avoids the eigenvalue decomposition of the matrix A and it requires about 10n3/3 operations for a general symmetric n × n matrix. When the matrix is tridiagonal, the required number of operations is only O(n2) and it can be further reduced to O(n) if only a column of the matrix function is needed. These efficient schemes for tridiagonal matrices are particularly useful when the Lanczos method is used to calculate the product of this matrix function (for a large symmetric matrix) with a given vector.
Coordination of Purchasing and Bidding Activities across Markets
Authors: Daniel D. Zeng, James C. Cox, Moshe Dror
Venue: Proceedings of the Proceedings of the 37th Annual Hawaii International Conference on System Sciences (HICSS'04) - Track 7 - Volume 7 (2004)

In both consumer purchasing and industrial procurement, combinatorial interdependencies among the items to be purchased are commonplace. E-commerce compounds the problem by providing more opportunities for switching suppliers at low costs, but also potentially eases theproblem by enabling automated market decision-making systems, commonly referred to as trading agents, to make purchasing decisions in an integrated manner across markets. Most of the existing research related to trading agents assumes that there exists a combinatorial market mechanism in which buyers (or sellers) can bid (or sell) service or merchandise bundles. Today's prevailing e-commerce practice, however, does not support this assumption in general and thus limits the practical applicability of these approaches. We are investigating a new approach to deal with the combinatorial interdependency challenges for online markets. This approach relies on existing commercial online market institutions such as posted-price markets and various online auctions that sell single items. It uses trading agents to coordinate a buyer's purchasing and bidding activities across multiple online markets simultaneously toachieve the best overall procurement effectiveness. This paper presents two sets of models related to this approach. The first set of models formalizes optimal purchasing decisions across posted-price markets with fixed transaction costs. Flat shipping costs, a common e-tailing practice, are captured in these models. We observe that making optimal purchasing decisions in this context is NP-hard in the strong sense and suggest several ef.cient computational methods based on discrete location theory. The second set of models is concerned with the coordination of bidding activities across multiple online auctions. We study the underlying coordination problem for a collection of first-or second-price sealed-bid auctions and derive the optimal coordination and bidding policies.
An undergraduate track in computer security
Authors: S. Azadegan, M. Lavine, M. O'Leary, A. Wijesinha, M. Zimand
Venue: Proceedings of the 8th annual conference on Innovation and technology in computer science education (2003)

To better prepare our graduates to face the challenges in computer and information security, in Fall 2002, Towson University launched an undergraduate track in computer security for the computer science majors. This paper describes the motivation behind this track and discusses its structure and requirements.
An incremental approach to reachability analysis of distributed programs
Authors: Kuo-Chung Tai, Pramod V. Koppol
Venue: Proceedings of the 7th international workshop on Software specification and design (1993)

In this paper we present an incremental approach to reachability analysis of distributed programs with synchronous communication and mailbox naming. Each process in a distributed program can be modeled as a communicating finite state machine (CFSM). A set of CFSMs is organized into a hierarchy. We present an algorithm that, for a given hierarchy of a set M of CFSMs, incrementally composes and reduces subsets of CFSMs in M. This incremental reachability analysis guarantees the detection of global deadlocks. We provide an algorithm for selecting a hierarchy for a set of CFSMs and show an incremental analysis of the gas station problem.
Resource Management Schemes in Optical Networks
Authors: N. Boudriga, M. S. Obaidat
Venue: Proceedings of the XXIII International Conference of the Chilean Computer Science Society (2003)

Advance resource reservation service in packet switched networks is a complex task. The decisionpoints to achieve such tasks include not only the start time of the requested connection, but also the instanceswhen the new connection may overlap with other connections that are already scheduled in the system. Thetask complexity is more important when the admission resource control is addressed in optical networks,particularly when service durations are uncertain, priorities are provided, and contention is possible. In thispaper, we study the issues of admission control, resource reservation, and delay in optical networks. A novelscheme for this purpose is devised. The main goals of our approach are to maximize user satisfaction in termsof quality of service (QoS) guarantees, service continuity, and reservation cost reduction.
A Case Study on Quality-Affecting Problems in Software Engineering Projects
Authors: Jarmo J. Ahonen, Tuukka Junttila
Venue: Proceedings of the IEEE International Conference on Software-Science, Technology & Engineering (2003)

Software engineering projects normally have many differentproblems related to all phases of the project. In additionto technical problems, the projects normally suffer fromproblems caused by management practices and conflicts ofinterests. In the study reported in this article we concentratedon quality affecting problems in one software company.The experts of the studied organization agreed on 22such problems. Almost all of those problems were related tomanagement or human issues, only three had clearly technicalcauses. In this article we describe those problems andtheir symptoms, causes and effects.
Double Ordering and Fill-In for the LU Factorization
Authors: Markus Baumann, Peter Fleischmann, Otto Mutzbauer
Venue: SIAM Journal on Matrix Analysis and Applications (2003)

We present a new method, called reversed double ordering, for reordering arbitrary matrices prior to LU factorization. This reordering creates a variable-band matrix. We compare the fill-in of the LU factorization for sparse matrices with respect to reversed double ordering, column minimum degree ordering, and the reversed Cuthill--McKee algorithm. Moreover, we combine the first two reorderings with good success.
A pervasive computing solution to asset, problem and knowledge management
Authors: Suman Kumar Kalia
Venue:  (2002)

In this dissertation we show that a pervasive computing approach to asset, problem, and knowledge management has a major positive impact on the cost-effectiveness and productivity of the Technical Support Function. Specifically, we show that it reduces time to complete all major tasks of the helpdesk functions and it leads to faster data availability, improved data quality, improved help desk effectiveness, improved help desk Return on Investment, lower overall Total Cost of Ownership, and increased user satisfaction. The research activities include the conceptualization, design, and construction of working wireless laptop and Pocket PC 2000 operating System PDA based asset, problem and knowledge management systems. These systems assist in the management of a divisional desktop support team across the U.S. The systems work on a Lotus Notes Domino based server supporting both wired desktops, wireless laptops, and wireless PDAs.
Predictive Prefetching on the Web and Its Potential Impact in the Wide Area
Authors: Christos Bouras, Agisilaos Konidaris, Dionysios Kostoulas
Venue: World Wide Web (2004)

The rapid increase of World Wide Web users and the development of services with high bandwidth requirements have caused the substantial increase of response times for users on the Internet. Web latency would be significantly reduced, if browser, proxy or Web server software could make predictions about the pages that a user is most likely to request next, while the user is viewing the current page, and prefetch their content.In this paper we study Predictive Prefetching on a totally new Web system architecture. This is a system that provides two levels of caching before information reaches the clients. This work analyses prefetching on a Wide Area Network with the above mentioned characteristics. We first provide a structured overview of predictive prefetching and show its wide applicability to various computer systems. The WAN that we refer to is the GRNET academic network in Greece. We rely on log files collected at the network's Transparent cache (primary caching point), located at GRNET's edge connection to the Internet. We present the parameters that are most important for prefetching on GRNET's architecture and provide preliminary results of an experimental study, quantifying the benefits of prefetching on the WAN. Our experimental study includes the evaluation of two prediction algorithms: an &ldquo;n most popular document&rdquo; algorithm and a variation of the PPM (Prediction by Partial Matching) prediction algorithm. Our analysis clearly shows that Predictive prefetching can improve Web response times inside the GRNET WAN without substantial increase in network traffic due to prefetching.
Organizational mission statements: a postmodernist perspective on the management of an IS/IT function
Authors: John Pillay, Ray Hackney
Venue: Advanced topics in information resources management (2003)

The mission statement embodies certain beliefs about the management culture of the organization, which can be examined and placed within underlying theoretical contexts. This chapter examines postmodernism in this respect, which, in addition to forming a critique of modernist approaches, posits alternative views about philosophy, organization and subsequently IS/ IT management theory. The study applies an ethnographic case research methodology where data was collected from 16 interviewees employed within a multi-national financial services group. In this way, the organizational mission statement was used as a vehicle for analyzing the contribution of postmodern approaches to the management of the IS/IT function. The influential Ashridge Model was adopted to map the findings of the study which suggest three propositions for postmodernism in providing: (i) cultural context, (ii) a textual or 'deconstructive' analysis and (iii) an ethnographic empathy for further IS/IT research. Finally, it is argued that the modernist/ postmodernist dialectic is ultimately a productive discussion, which can positively contribute towards research in terms of analytical techniques and interpretative strategies.