ppxscal/embedding_network huggingface dataset:
Unequal sampling for Monte Carlo EM algorithms
Authors: James G. Booth, Brian S. Caffo
Venue: Computational Statistics Data Analysis (2002)

The EM algorithm is a widely used tool for calculating maximum likelihood estimates in problems involving incomplete data. The E-step of the algorithm involves an expectation of the complete data log-likelihood conditional on observed data. Even if the expectation step of the EM algorithm is analytically intractable it can often be approximated via Monte Carlo techniques. In many applications of EM the expectation step involves a sum of independent but not identically distributed components. In such cases, the sum of expectations can be approximated by a sum independent Monte Carlo means. All applications of Monte Carlo EM that we are aware of use an equal allocation rule for the Monte Carlo sample sizes in this setting. However, if the log-likelihood components have unequal variances, then it is clearly more efficient to use an unequal allocation rule. In this note, we discuss allocation rules for Monte Carlo resources and suggest a general but simple procedure for improving the efficiency of Monte Carlo implementations of the EM algorithm.
Strategies of Engagement: Lessons From the Critical Examination of Collaboration and Conflict in An Interorganizational Design
Authors: Cynthia Hardy, Nelson Phillips
Venue: Organization Science (1998)

Many writers advocate interorganizational collaboration as a solution to a range of organizational and in tersectoral problems. Accordingly, they often concentrate on its functional aspects. We argue that collaboration deserves a more critical examination, particularly when the interests of stakeholders conflict and the balance of power between them is unequal. Using examples from a study of the UK refugee system, we argue that collaboration is only one of several possible strategies of engagement used by organizations as they try to manage the interorganizational domain in which they operate. In this paper, we discuss four such strategies: collaboration, compliance, contention and contestation. By examining the stakeholders in the domain and asking who has formal authority, who controls key resources, and who is able to discursively manage legitimacy, resear chers are in a stronger position to evaluate both the benefits and costs of these strategies and to differentiate more clearly between strategies that are truly collaborative and strategies that are not. In other words, we hope to demonstrate that collabo ration between organizations is not necessarily "good", conflict is not necessarily "bad", and surface dynamics are not necessarily an accurate representation of what is going on beneath.
The kernel configuration and build process
Authors: Greg Kroah-Hartman
Venue: Linux Journal (2003)

Configuring and building the kernel is simpler and more flexible than 2.4 and before. Here's how to customize your kernel or integrate your new feature.
Spam, spam, spam, spam: how can we stop it
Authors: Jenny Preece, Jonathan Lazar, Elizabeth Churchill, Hans de Graaff, Batya Friedman, Joseph Konstan
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

How do we keep our channels of electronic communication, both individual and group, open, while keeping out inappropriate and unrelated materials, such as spam? Does someone other than the intended recipient have the right to control what electronic mail users see? Might this lead to censorship? If others DO have the right to control what e-mail users see, how should this filtering or censorship occur? Are users aware of this filtering? If others are NOT controlling what users receive, what can users themselves do to control their environments to limit the amount of incoming spam? These are some of the topics that this CHI panel will address.
Clockspeed and Informational Response: Evidence From the Information Technology Industry
Authors: Haim Mendelson, Ravindran R. Pillai
Venue: Information Systems Research (1998)

This paper presents evidence on ways in which firms in the IT industry respond to increased business dynamics. We show that the use of internal and external communication technologies and the adoption of informational "focus" strategies increase with the "clockspeed," or dynamics, of the business environment. Our results support the information processing view of the firm.
Error indicators for the mortar finite element discretization of the Laplace equation
Authors: Christine Bernardi, Frédéric Hecht
Venue: Mathematics of Computation (2002)

The mortar technique turns out to be well adapted to handle mesh adaptivity in finite elements, since it allows for working with nonnecessarily compatible discretizations on the elements of a nonconforming partition of the initial domain. The aim of this paper is to extend the numerical analysis of residual error indicators to this type of methods for a model problem and to check their efficiency thanks to some numerical experiments.
Worst case analysis of a greedy algorithm for graph thickness
Authors: Sinichiro Kawano, Koichi Yamazaki
Venue: Information Processing Letters (2003)

In this paper, we consider a greedy algorithm for thickness of graphs. The greedy algorithm we consider here takes a maximum planar subgraph away from the current graph in each iteration and repeats this process until the current graph has no edge. The greedy algorithm outputs the number of iterations which is an upper bound of thickness for an input graph G = (V, E). We show that the performance ratio of the greedy algorithm is Ω (log |V|).
Object models as heap invariants
Authors: Daniel Jackson
Venue: Programming methodology (2003)

Object models are widely used for describing structural properties of object-oriented programs, but they suffer from two problems. First, their semantics is usually unclear. Second, the textual constraints that are often used to annotate diagrams are not integrated with the diagrammatic notation itself. In this paper, we show how to interpret an object model as a heap invariant by translation to a small relational logic. With a few additional shorthands, this logic can be used for textual constraints, so that annotation is just conjunction. Our semantics is simpler than those proposed by others, and accounts for features of the object model that have not been addressed in treatments that focus on more abstract models.
Oscillation and stability of nonlinear neutral impulsive delay differential equations
Authors: Yongrui Duan, Peng Tian, Shunian Zhang
Venue: The Korean Journal of Computational Applied Mathematics (2003)

In this paper, oscillation and stability of nonlinear neutral impulsive delay differential equation are studied. The main result of this paper is that oscillation and stability of nonlinear impulsive neutral delay differential equations are equivalent to oscillation and stability of corresponding nonimpulsive neutral delay differential equations. At last, two examples are given to illustrate the importance of this study.
Graph-theoretical versus topological ends of graphs
Authors: Reinhard Diestel, Daniela Kühn
Venue: Journal of Combinatorial Theory Series B (2003)

We compare the notions of an end that exist in the graph-theoretical and, independently, in the topological literature. These notions conflict except for locally finite graphs, and we show how each can be expressed in the context of the other. We find that the topological ends of a graph are precisely the undominated of its graph-theoretical ends, and that graph theoretical ends have a simple topological description generalizing the definition of a topological end.
Army Operations Research--Historical Perspectives and Lessons Learned
Authors: Seth Bonder
Venue: Operations Research (2002)

This paper provides some of my historical perspectives on Operations Research (OR) in the U.S. Army. It is based on my 40+ years of personal experience and, thus, focuses on the modeling and analysis (M&amp;A) aspects of OR in the Army. I have attempted to highlight the changing problems and growth of M&amp;A in the Army over the past 40 years. Although I refer to approaches taken by others for some of this growth, more information is provided on those of Vector Research,Incorporated (VRI),since all of my experience has been with VRI since 1969. The paper has four main sections. Since OR in the Army started before 1960 and my activities interacted with many others in the Army, the first section briefly reviews the lineage of some of the Army's main OR organizations. The second and third summarize my M&amp;A activities and perspectives for the periods 1960--1989 (the "Cold War" era) and 1990--2000, respectively. Based on this experience, I offer some "lessons learned" for today's military M&amp;A community in the concluding section.
A genetic-neuro algorithm for tiling problems with rotation and/or reflection of figures
Authors: R. Monsefi, M. A. Toosi
Venue: Iranian Journal of Science and Technology (2002)

This paper describes an algorithm for tiling with polyminoes that consider rotation and/or reflection of figures in the steps of 90°. First, we review the previous parallel algorithms for tiling problems. Next, we propose a hybrid approach that is based on genetic algorithms (GA) and artificial neural networks(ANN). In this approach, the production of new members in GA and their evaluation are performed by a Hopfield neural network. Finally we compare our method with the previous works, and show that our method can produce global minima for many problems. The algorithm can be used for solving a variety of 2D-packing problems.
Dynamic modelling of high power single-phase "written pole" motors
Authors: H. Zabet Khosousi, M. Mirsalim
Venue: Iranian Journal of Science and Technology (2002)

This paper presents a dynamic model to simulate the high power single-phase "Written Pole" motors. The base of this modeling is generalized theory of electrical machines. Based on this theory, first, the required equations governing the dynamic behavior of these motors are obtained. Next, the equations are solved in a special reference frame, which is valid for the unique properties of single-phase "Written Pole" motors. Finally, the comparison of simulating results of the modeling with the experimental ones shows high agreement.
It's About Time: Temporal Structuring in Organizations
Authors: Wanda J. Orlikowski, JoAnne Yates
Venue: Organization Science (2002)

In this paper we propose the notion of temporal structuring as a way of understanding and studying time as an enacted phenomenon within organizations. We suggest that through their everyday action, actors produce and reproduce a variety of temporal structures which in turn shape the temporal rhythm and form of their ongoing practices. A focus on temporal structuring, combined with a practice perspective, allows us to bridge the subjective-objective dichotomy that underlies much of the existing research on time in organizations. After developing the notion of temporal structuring, we illustrate its use in the context of a prior empirical study. We conclude by outlining some implications of temporal structuring for organizational research on time.
Designing an on-line map tool for Dutch farmers
Authors: Karin van der Hiele, Rob van der Haar, Raghu Kolli
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

This paper describes our real life experience in designing an on-line map user interface for the Dutch farmers. The project challenge was to design a simple user interface for advanced mapping technology in a critical schedule. The domain involved understanding of several technical and legal constraints. We studied the context of use, designed the user interface concept, evaluated a prototype and provided the developers with detailed specifications during a four week period.
Making Sense in Hypercompetitive Environments: A Cognitive Explanation for the Persistence of High Velocity Competition
Authors: William C. Bogner, Pamela S. Barr
Venue: Organization Science (2000)

This paper explores the cognitive aspects underlying industries in hypercompetitive environments. Hypercompetition represents a state of competition with rapidly escalating levels of competition and reduced periods of competitive advantage for firms. In hypercompetitive industries member firms act boldly and aggressively to create a state of competitive disequilibrium. In this paper we explore the particular conditions that managers encounter in making sense of hypercompetitive industries and argue that the nature of these conditions is such that conventional sensemaking frameworks will not work. We then describe the 'adaptive sensemaking' practices established in the literature for dealing with temporary turbulence and suggest that in hypercompetition those processes continue indefinitely. We argue that these processes can become institutionalized as standard operating procedures within firms, and as shared recipes within industries, which in turn perpetuates hyperturbulent conditions.
Multi-criterion optimization for genetic network modeling
Authors: E. P. van Someren, L. F. A. Wessels, E. Backer, M. J. T. Reinders
Venue: Signal Processing (2003)

A major problem associated with the reverse engineering of genetic networks from micro-array data is how to reliably find genetic interactions when faced with a relatively small number of arrays compared to the number of genes. To cope with this dimensionality problem, it is imperative to employ additional (biological) knowledge about real genetic networks, such as limited connectivity, redundancy, stability and robustness, to sensibly constrain the modeling process. In previous work (Proceedings of the 2001 IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing, Baltimore, MA, June 2001; Proceedings of the Second International Conference on Systems Biology, Pasadena, CA, November 2, pp. 222-230), we have shown that by applying single constraints, the inference of genetic interactions under realistic conditions can be significantly improved. Recently (Proceedings of the SPIE, San Jose, CA, January 2002), we have made a preliminary study on how these approaches based on single constraints solve the underlying bi-criterion optimization problem. In this paper, we study the problem of how multiple constraints can be combined by formulating genetic network modeling as a multi-criterion optimization problem. Results are shown on artificial as well as on a real data example.
Leveled-commitment contracting: a backtracking instrument for multiagent systems
Authors: Tuomas Sandholm, Victor Lesser
Venue: AI Magazine (2002)

In (automated) negotiation systems for self-interested agents, contracts have traditionally been binding. They do not accommodate future events. Contingency contracts address this but are often impractical. As an alternative, we propose leveled-commitment contracts. The level of commitment is set by decommitting penalties. To be freed from the contract, an agent simply pays its penalty to the other contract party(ies). A self-interested agent will be ruluctant to decommit because some other contract party might decommit, in which case the former agent gets freed from the contract, does not incur a penalty, and collects a penalty from the other party. We show that despite such strategic decommitting, leveled commitment increases the expected payoffs of all contract parties and can enable deals that are impossible under full commitment. Different decommitting mechanisms are introduced and compared. Practical prescriptions for market designers are presented. A contract optimizer, ECOMMITTER, is provided on the web.
General schema theory for genetic programming with subtree-swapping crossover: part I
Authors: Riccardo Poli, Nicholas Freitag McPhee
Venue: Evolutionary Computation (2003)

This is the first part of a two-part paper which introduces a general schema theory for genetic programming (GP) with subtree-swapping crossover. The theory is based on a Cartesian node reference system which makes it possible to describe programs as functions over the space N2 and allows one to model the process of selection of the crossover points of subtree-swapping crossovers as a probability distribution over N4. In Part I, we present these notions and models and show how they can be used to calculate useful quantities. In Part II we will show how this machinery, when integrated with other definitions, such as that of variable-arity hyperschema, can be used to construct a general and exact schema theory for the most commonly used types of GP.
Grasp and Path Relinking for 2-Layer Straight Line Crossing Minimization
Authors: Manuel Laguna, Rafael Marti
Venue: INFORMS Journal on Computing (1999)

In this article, we develop a greedy randomized adaptive search procedure (GRASP) for the problem of minimizing straight line crossings in a 2-layer graph. The procedure is fast and is particularly appealing when dealing with low-density graphs. When a modest increase in computational time is allowed, the procedure may be coupled with a path relinking strategy to search for improved outcomes. Although the principles of path relinking have appeared in the tabu search literature, this search strategy has not been fully implemented and tested. We perform extensive computational experiments with more than 3,000 graph instances to first study the effect of changes in critical search parameters and then to compare the efficiency of alternative solution procedures. Our results indicate that graph density is a major influential factor on the performance of a solution procedure.
Layered 4D Representation and Voting for Grouping from Motion
Authors: Mircea Nicolescu, Gérard Medioni
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2003)

We address the problem of perceptual grouping from motion cues by formulating it as a motion layers inference from a sparse and noisy point set in a 4D space. Our approach is based on a layered 4D representation of data, and a voting scheme for token communication, within a tensor voting computational framework. Given two sparse sets of point tokens, the image position and potential velocity of each token are encoded into a 4D tensor. By enforcing the smoothness of motion through a voting process, the correct velocity is selected for each input point as the most salient token. An additional dense voting step allows for the inference of a dense representation in terms of pixel velocities, motion regions, and boundaries. Using a 4D space for this tensor voting approach is essential since it allows for a spatial separation of the points according to both their velocities and image coordinates. Unlike most other methods that optimize certain objective functions, our approach is noniterative and, therefore, does not suffer from local optima or poor convergence problems. We demonstrate our method with synthetic and real images, by analyzing several difficult cases¿opaque and transparent motion, rigid and nonrigid motion, curves and surfaces in motion.
Price Protection in the Personal Computer Industry
Authors: Hau L. Lee, V. Padmanabhan, Terry A. Taylor, Seungjin Whang
Venue: Management Science (2000)

Price protection is a commonly used practice between manufacturers and retailers in the personal computer (PC) industry, motivated by drastic declines of product values during the product life cycle. It is a form of rebate given by the manufacturer to the retailer for units unsold at the retailer when the price drops during the product life cycle. It is a controversial policy in the PC industry because it is not clear how such a policy benefits the supply chain and its participants. We show that price protection is an instrument for channel coordination. For products with long manufacturing lead times, so the retailer has a single buying opportunity, a properly chosen price protection credit coordinates the channel. For products with shorter manufacturing lead times, so the retailer has two buying opportunities, price protection alone cannot guarantee channel coordination when wholesale prices are exoge-nous. However, when the price protection credit is set endogenously together with the wholesale prices, channel coordination is restored. In the two-buying-opportunity setting with fixed wholesale prices, we show that price protection has two primary impacts: (1) shifting sales forward in time and (2) increasing total sales. Finally, we present a simple numerical example that suggests, given the current economics of the PC industry, that price protection under fixed wholesale prices may benefit the total chain and the retailer but hurt the manufacturer.
Crossing numbers of random graphs
Authors: Joel Spencer, Géza Tóth
Venue: Random Structures Algorithms (2002)

The crossing number of G is the minimum number of crossing points in any drawing of G. We consider the following two other parameters. The rectilinear crossing number is the minimum number of crossing points in any drawing of G, with straight line segments as edges. The pairwise crossing number of G is the minimum number of pairs of crossing edges over all drawings of G. We prove several results on the expected values of these parameters of a random graph.
Problems of Robustness for Universal Coding Schemes
Authors: V. V. V'yugin
Venue: Problems of Information Transmission (2003)

The Lempel&ndash;Ziv universal coding scheme is asymptotically optimal for the class of all stationary ergodic sources. A problem of robustness of this property under small violations of ergodicity is studied. The notion of deficiency of algorithmic randomness is used as a measure of disagreement between data sequence and probability measure. We prove that universal compression schemes from a large class are nonrobust in the following sense: If the randomness deficiency grows arbitrarily slowly on initial fragments of an infinite sequence, then the property of asymptotic optimality of any universal compression algorithm can be violated. Lempel&ndash;Ziv compression algorithms are robust on infinite sequences generated by ergodic Markov chains when the randomness deficiency of their initial fragments of length n grows as o(n).
An expert system for mineral identification
Authors: Michael Starek, Mukesh Tomer, Krishna Bhaskar, Mario Garcia
Venue: Journal of Computing Sciences in Colleges (2002)

The purpose of this research was the implementation of an Expert System for Mineral Identification. The Expert System can be used to support the teaching of mineral properties at college level and hence promote effective and meaningful learning of scientific observations in Earth Science. The software application is designed to have a simple interface and easy to follow help. For this project 32 different minerals were used. The software can be easily expanded to accommodate more minerals. The pilot test taken by students gave a positive response in making learning of mineral identification through computers more effective.
Immersive sound field simulation in multi-screen projection displays
Authors: T. Ogi, T. Kayahara, M. Kato, H. Asayama, M. Hirose
Venue: Proceedings of the workshop on Virtual environments 2003 (2003)

This paper describes the immersive sound field simulation technology that represents an interactive sound field in the multi-screen projection display. In this method, convolution filters, that were calculated based on the wave equation, are replaced in real-time using the multi-channel digital signal processor, and the simulated sounds are displayed using the 16-channel speakers. In addition, compensation filters are used to reduce the influence of the screen attenuation. This system was applied to the video avatar communication, and the effectiveness of this method was evaluated.