ppxscal/embedding_network huggingface dataset:
One-to-one piecewise linear mappings over triangulations
Authors: Michael S. Floater
Venue: Mathematics of Computation (2003)

We call a piecewise linear mapping from a planar triangulation to the plane a convex combination mapping if the image of every interior vertex is a convex combination of the images of its neighbouring vertices. Such mappings satisfy a discrete maximum principle and we show that they are one-to-one if they map the boundary of the triangulation homeomorphically to a convex polygon. This result can be viewed as a discrete version of the Radó-Kneser-Choquet theorem for harmonic mappings, but is also closely related to Tutte's theorem on barycentric mappings of planar graphs.
One class SVM for yeast regulation prediction
Authors: Adam Kowalczyk, Bhavani Raskutti
Venue: ACM SIGKDD Explorations Newsletter (2002)

In this paper, we outline the main steps leading to the development of the winning solution for Task 2 of KDD Cup 2002 (Yeast Gene Regulation Prediction). Our unusual solution was a pair of linear classifiers in high dimensional space (&sim;14,000), developed with just 38 and 84 training examples, respectively, all belonging to the target class only. The classifiers were built using the support vector machine approach outlined in the paper.
A nonlinear version of the Kantorovich-Rubinstein maximum principle
Authors: Henryk Gacki, Andrzej Lasota
Venue: Nonlinear Analysis: Theory, Methods Applications (2003)

The classical Kantorovich-Rubinstein theory gives necessary conditions for maxima of linear functionals acting on the space of Lipsehitzian functions. We show analogous results for some nonlinear functionals of Hammerstein type. Our proofs are based on theorems concerning local changes of Lipschitzian functions similar to the McShane extension theorem.
A Project for Hand Gesture Recognition
Authors: Carlos R. P. Dionisio, Roberto M. Cesar,  Jr.
Venue: Proceedings of the 13th Brazilian Symposium on Computer Graphics and Image Processing (2000)

This paper discusses an ongoing project for hand gesture recognition in computer vision systems. The proposed approach is based on the shape analysis tools introduced by R.M. Cesar Jr. and L. da F. Costa (1997). More specifically, the wavelet transform is used to generate features for the recognition of hand gestures based on contours.
Background and overview for KDD Cup 2002 task 1: information extraction from biomedical articles
Authors: Alexander Yeh, Lynette Hirschman, Alexander Morgan
Venue: ACM SIGKDD Explorations Newsletter (2002)

This paper presents a background and overview for task 1 (of 2 tasks) of the KDD Challenge Cup 2002, a competition held in conjunction with the ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD), July 23--26, 2002. Task 1 dealt with detecting which papers, in a set of fruitfly genetics papers (texts), contained experimental results about gene products (transcripts and proteins), and also within each paper, which genes had experimental results about their products mentioned.
XORP: an open platform for network research
Authors: Mark Handley, Orion Hodson, Eddie Kohler
Venue: ACM SIGCOMM Computer Communication Review (2003)

Network researchers face a significant problem when deploying software in routers, either for experimentation or for pilot deployment. Router platforms are generally not open systems, in either the open-source or the open-API sense. In this paper we discuss the problems this poses, and present an eXtensible Open Router Platform (XORP) that we are developing to address these issues. Key goals are extensibility, performance and robustness. We show that different parts of a router need to prioritize these differently, and examine techniques by which we can satisfy these often conflicting goals. We aim for XORP to be both a research tool and a stable deployment platform, thus easing the transition of new ideas from the lab to the real world.
An algorithm for an inventory model with inventory-level-dependent demand rate
Authors: Kun-Jen Chung
Venue: Computers and Operations Research (2003)

In 1990, Datta and Pal (J. Oper. Res. Soc. 41 (1990) 971) discussed an infinite time-horizon deterministic inventory model without shortages. In essence, they concentrate on the establishment of the inventory model but do not present a concrete solution procedure to solve the model. This paper deals with an alternative approach to find the optimal order quantity for Datta and Pal.
Sketches with Curvature: The Curve Indicator Random Field and Markov Processes
Authors: Jonas August, Steven W. Zucker
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2003)

While complaints about typical edge operators are common, proposals articulating a notion of the ¿perfect¿ edge map are comparatively rare, hindering the improvement of contour enhancement techniques. To address this situation, we suggest that one objective of visual contour computation is the estimation of a clean sketch from a corrupted rendition, the latter modeling noisy and low contrast edge or line operator responses to an image. Our formal model of this clean sketch is the curve indicator random field (CIRF), whose role is to provide a basis for defining edge likelihood models by eliminating the parameter along each curve to create an image of curves. For curves modeled with stationary Markov processes, this ideal edge prior is non-Gaussian and its moment generating functional has a form closely related to the Feynman-Kac formula. This sketch model leads to a nonlinear, minimum mean squared error contour enhancement filter that requires the solution of two elliptic partial differential equations. The framework is also independent of the order of the contour model, allowing us to introduce a Markov process model for contour curvature. We analyze the distribution of such curves and show that its mode is the Euler spiral, a curve minimizing changes in curvature. Example computations using the contour enhancement filter with the curvature-based contour model are provided, highlighting how the filter is curvature-selective even when curvature is absent in the input.
We know where you are: the ethics of LBS advertising
Authors: Patricia J. O'Connor, Susan H. Godar
Venue: Mobile commerce: technology, theory, and applications (2003)

Privacy is the most significant and complex ethical issue facing LBS. While LBS is more than the combination of e-commerce and telemarketing, we use the ethical failures of those two media to show that consumers will seek legislative action to protect themselves from invasions of privacy using the new medium. The alternative is effective self-regulation by the industry; we conclude with a proposed model for such self-regulation, involving existing trade groups.
Behaviour of compartment masonry walls in fire situations
Authors: A. Nadjai, D. Laverty, M. O'Gara
Venue: Civil and structural engineering computing: 2001 (2001)

A mathematical model is developed to simulate the lateral deflection response of axially loaded masonry walls subjected to elevated temperatures. The developed model is based on the method of slice approach dividing the wall into a series of discrete slices and generates 'through the thickness' changes in material properties and stress strain relationships. The transient nature of the fire process is modelled using a time step analysis applying thermal profiles derived from Lagrangian shape functions acting on temperatures at specific node points, the latter determined experimentally. To verify the model an experimental programme was conducted on scale model walls of different height and subjected to different loads.
Computer security: theory, process and management
Authors: George Whitson
Venue: Journal of Computing Sciences in Colleges (2003)

The Internet backbone servers were attacked and Web traffic slowed for a few hours, the Nimbda worm used Microsoft Web servers to infect all those downloading Web pages until appropriate patches were applied and credit card information is stolen every day. These are just some well known examples of breaches in computer security, but it is difficult to define computer security. Even when you get a good dictionary definition it is difficult to give a systematic description of the entire field. This paper gives a high-level overview of computer security that organizes the mass of seemingly unrelated subjects of computer security into a manageable whole. They key concept of the organization is that computer security consists of some basic theory, like cryptography and network protocols; a software engineering process that is used to systematically develop computer security systems and management techniques that are used to keep a computer security system operating.The organization of computer security described in the paper is the result of experiences gained in developing a one semester course on computer security that gives students a real understanding of all aspects of computer security. The course has an introduction to cryptography, but is not overly mathematical. It uses software engineering techniques to develop computer security systems, but does not follow any one known modeling technique. And, while discussing intrusion detection, it is not a dictionary on hacking. The course is a Web-based distance education course and has some unique assignments, described in the paper that can be done by students who do not have access to university labs.
Telecommuting: Justice and Control in the Virtual Organization
Authors: Nancy B. Kurland, Terri D. Egan
Venue: Organization Science (1999)

The adoption of telecommuting raises concerns for both managers and employees: Remote supervision presents monitoring challenges, while physical isolation may impede the employee's opportunity for, and involvement in, determining valued organizational outcomes (organizational justice). This study of 191 employees examined the relationships among telecommuting, organizational monitoring strategies, and organizational justice perceptions. Results suggest that monitoring strategies were more strongly associated with organizational justice perceptions than with telecommuting, and procedural and interactional justice perceptions related significantly to telecommuting. We provide implications, limitations, and ideas for future research.
Dual mesh resampling
Authors: Gabriel Taubin
Venue: Graphical Models (2002)

The dual of a 2-manifold polygonal mesh without boundary is commonly defined as another mesh with the same topology (genus) but different connectivity (vertex-face incidence), in which faces and vertices occupy complementary locations and the position of each dual vertex is computed as the center of mass (barycenter or centroid) of the vertices that support the corresponding face. This barycenter dual mesh operator is connectivity idempotent but not geometrically idempotent for any choice of vertex positions, other than constants. In this paper we construct a new resampling dual mesh operator that is geometrically idempotent for the largest possible linear subspace of vertex positions. We look at the primal and dual mesh connectivities as irregular sampling spaces and at the rules to determine dual vertex positions as the result of a resampling process that minimizes signal loss. Our formulation, motivated by the duality of Platonic solids, requires the solution of a simple least-squares problem. We introduce a simple and efficient iterative algorithm closely related to Laplacian smoothing and with the same computational cost. We also characterize the configurations of vertex positions where signal loss does and does not occur during dual mesh resampling and the asymptotic behavior of iterative dual mesh resampling in the general case. Finally, we describe the close relation existing with discrete fairing and variational subdivision, and define a new primal-dual interpolatory recursive subdivision scheme.
Converting XML DTDs to UML diagrams for conceptual data integration
Authors: Mikael R. Jensen, Thomas H. Møller, Torben Bach Pedersen
Venue: Data Knowledge Engineering (2003)

Extensible Markup Language (XML) is fast becoming the new standard for data representation and exchange on the World Wide Web, e.g., in B2B e-commerce. Modern enterprises need to combine data from many sources in order to answer important business questions, creating a need for integration of web-based XML data. Previous web-based data integration efforts have focused almost exclusively on the logical level of data models, creating a need for techniques that focus on the conceptual level in order to communicate the structure and properties of the available data to users at a higher level of abstraction. The most widely used conceptual model at the moment is the Unified Modeling Language (UML).This paper presents algorithms for automatically constructing UML diagrams from XML DTDs, enabling fast and easy graphical browsing of XML data sources on the web. The algorithms capture important semantic properties of the XML data such as precise cardinalities and aggregation (containment) relationships between the data elements. As a motivating application, it is shown how the generated diagrams can be used for the conceptual design of data warehouses based on web data, and an integration architecture is presented. The choice of data warehouses and On-Line Analytical Processing as the motivating application is another distinguishing feature of the presented approach.
Enhancing retrieval with hyperlinks: a general model based on propositional argumentation systems
Authors: Justin Picard, Jacques Savoy
Venue: Journal of the American Society for Information Science and Technology (2003)

Fast, effective, and adaptable techniques are needed to automatically organize and retrieve information on the ever-increasing World Wide Web. In that respect, different strategies have been suggested to take hypertext links into account. For example, hyperlinks have been used to (1) enhance document representation, (2) improve document ranking by propagating document score, (3) provide an indicator of popularity, and (4) find hubs and authorities for a given topic. Although the TREC experiments have not demonstrated the usefulness of hyperlinks for retrieval, the hypertext structure is nevertheless an essential aspect of the Web, and as such, should not be ignored. The development of abstract models of the IR task was a key factor to the improvement of search engines. However, at this time conceptual tools for modeling the hypertext retrieval task are lacking, making it difficult to compare, improve, and reason on the existing techniques. This article proposes a general model for using hyperlinks based on Probabilistic Argumentation Systems, in which each of the above-mentioned techniques can be stated. This model will allow to discover some inconsistencies in the mentioned techniques, and to take a higher level and systematic approach for using hyperlinks for retrieval.
A Branch-First, Cut-Second Approach for Locomotive Assignment
Authors: Koorush Ziarati, François Soumis, Jacques Desrosiers, Marius M. Solomon
Venue: Management Science (1999)

The problem of assigning locomotives to trains consists of selecting the types and number of engines that minimize the fixed and operational locomotive costs resulting from providing sufficient power to pull trains on fixed schedules. The force required to pull a train is often expressed in terms of horsepower and tonnage requirements rather than in terms of number of engines. This complicates the solution process of the integer programming formulation and usually creates a large integrality gap. Furthermore, the solution of the linearly relaxed problem is strongly fractional. To obtain integer solutions, we propose a novel branch-and-cut approach. The core of the method consists of branching decisions that define on one branch the projection of the problem on a low-dimensional subspace. There, the facets of the polyhedron describing a restricted constraint set can be easily derived. We call this approach branch-first, cut-second. We first derive facets when at most two types of engines are used. We then extend the branching rule to cases involving additional locomotive types. We have conducted computational experiments using actual data from the Canadian National railway company. Simulated test-problems involving two or more locomotive types were solved over 1-, 2-, and 3-day rolling horizons. The cuts were successful in reducing the average integrality gap by 52% for the two-type case and by 34% when more than 25 types were used. Furthermore, the branch-first, cut-second approach was instrumental in improving the best known solution for an almost 2,000-leg weekly problem involving 26 locomotive types. It reduced the number of locomotives by 11, or 1.1%, at an equivalent savings of $3,000,000 per unit. Additional tests on different weekly data produced almost identical results.
Politics and usability: test your skills against the experts
Authors: Rolf Molich, Kara Pernice Coyne, Ron Perkins, Deborah J. Mayhew
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

In this highly interactive panel we will present and discuss a Usability Business Case for professional self-assessment dealing with the Politics of Usability. A usability business case is a hypothetical but realistic scenario that serves to illustrate points of great importance to usability professionals. Our usability business case will focus on the politics of usability: The fundamental rules that apply when attempting to sell or even evangelize usability in an organization. This panel is particularly important since preliminary tests of our business case with experienced usability professionals shows that the general familiarity with our key points is limited.
On-line stream merging in a general setting
Authors: Wun-Tat Chan, Tak-Wah Lam, Hing-Fung Ting, Prudence W. H. Wong
Venue: Theoretical Computer Science (2003)

This paper is concerned with on-line scheduling algorithms for merging streams in a video-on-demand system so as to minimize the server bandwidth. We present the first algorithm that has a constant competitive factor (precisely, 5). Our algorithm, unlike previous ones, is not limited to the scenario where clients are equipped with large buffer and client receiving bandwidth. It remains 5-competitive in all settings of buffer size and receiving bandwidth. Technically speaking, our algorithm is based on a novel observation that the behavior of any schedule can be modeled by a rectilinear (binary) tree on a grid. This observation eases the analysis of our algorithm as well as the optimal algorithm.
A Single-Item Inventory Model for a Nonstationary Demand Process
Authors: Mahmoud H. Alrefaei, Sigrún Andradóttir, Stephen C. Graves
Venue: Manufacturing Service Operations Management (1999)

In this paper, we consider an adaptive base-stock policy for a single-item inventory system, where the demand process is nonstationary. In particular, the demand process is an integrated moving average process of order (0, 1, 1), for which an exponential-weighted moving average provides the optimal forecast. For the assumed control policy we characterize the inventory random variable and use this to find the safety stock requirements for the system. From this characterization, we see that the required inventory, both in absolute terms and as it depends on the replenishment lead-time, behaves much differently for this case of nonstationary demand compared with stationary demand. We then show how the single-item model extends to a multi-stage, or supply-chain context; in particular we see that the demand process for the upstream stage is not only nonstationary but also more variable than that for the downstream stage. We also show that for this model there is no value from letting the upstream stages see the exogenous demand. The paper concludes with some observations about the practical implications of this work.
Minimum Time and Minimum Cost-Path Problems in Street Networks with Periodic Traffic Lights
Authors: Ravindra K. Ahuja, James B. Orlin, Stefano Pallottino, Maria Grazia Scutellà
Venue: Transportation Science (2002)

This paper investigates minimum time and minimum cost path problems in street networks regulated by periodic traffic lights. We show that the minimum time path problem is polynomially solvable. On the other hand, minimum cost path problems are generally NP-hard. Special, realistic cases which are polynomially solvable are discussed.
A Two-Stage Stochastic Network Model and Solution Methods for the Dynamic Empty Container Allocation Problem
Authors: Raymond K. Cheung, Chuen-Yih Chen
Venue: Transportation Science (1998)

Containerized liner trades have been growing steadily since the globalization of world economies intensified in the early 1990s. However, these trades are typically imbalanced in terms of the numbers of inbound and outbound containers. As a result, the relocation of empty containers has become one of the major problems faced by liner operators. In this paper, we consider the dynamic empty container allocation problem where we need to reposition empty containers and to determine the number of leased con tainers needed to meet customers? demand over time. We formulate this problem as a two-stage stochastic network: in stage one, the parameters such as supplies, demands, and ship capacities for empty containers are deterministic; whereas in stage two, these parameters are random variables. We need to make decisions in stage one such that the total of the stage one cost and the expected stage two cost is minimized. By taking advantage of the network structure, we show how a stochastic quasi-gradient method and a stochastic hybrid approximation procedure can be applied to solve the problem. In addition, we propose some new variations of these methods that seem to work faster in practice. We conduct numerical tests to evaluate the value of the two-stage stochastic model over a rolling horizon environment and to investigate the behavior of the solution methods with different implementations.
The Underlying Markov Decision Process in the Single-Leg Airline Yield-Management Problem
Authors: Conrad J. Lautenbacher, Shaler Stidham,  Jr.
Venue: Transportation Science (1999)

We introduce the terms dynamic and static, respectively, to identify the prevailing approaches to the single-leg airline yield-management problem: those allowing customers of different fare classes to book concomitantly (dynamic), and those assuming that the demands for the different fare classes arrive separately in a predetermined order (static). We present a coherent frame-work linking these seemingly disparate models through the underlying dynamic program common to both. We develop a discrete-time Markov decision process formulation mirroring that of Janakiram et al. Transp. Sci. 33, 147Â 167 (1999) to solve the single-leg problem without cancellations, overbooking, or discounting. Borrowing a result from the queueing-control literature, we prove the concavity of the associated optimal value functions and, subsequently, the optimality of a booking limit policy. We then apply this same technique to the more influential papers from the single-leg literature, at once unifying the static and dynamic models and establishing the connection between the yield-management and queueing-control problems. Finally, we propose an omnibus formulation that yields the static and dynamic models as special cases.