ppxscal/embedding_network huggingface dataset:
Exchanging Preliminary Information in Concurrent Engineering: Alternative Coordination Strategies
Authors: Christian Terwiesch, Christoph H. Loch, Arnoud De Meyer
Venue: Organization Science (2002)

Successful application of concurrent development processes (concurrent engineering) requires tight coordination. To speed development, tasks often proceed in parallel by relying on preliminary information from other tasks, information that has not yet been finalized. This frequently causes substantial rework using as much as 50% of total engineering capacity. Previous studies have either described coordination as a complex social process, or have focused on the frequency, but not the content, of information exchanges. Through extensive fieldwork in a high-end German automotive manufacturer, we develop a framework of preliminary information that distinguishes information precision and information stability. Information precision refers to the accuracy of the information exchanged. Information stability defines the likelihood of changing a piece of information later in the process.This definition of preliminary information allows us to develop a time-dependent model for managing interdependent tasks, producing two alternative strategies: iterative and set-based coordination. We discuss the trade-offs in choosing a coordination strategy and how they change over time. This allows an organization to match its problem-solving strategy with the interdependence it faces. Set-based coordination requires an absence of ambiguity, and should be emphasized if either starvation costs or the cost of pursuing multiple design alternatives in parallel are low. Iterative coordination should be emphasized if the downstream task faces ambiguity, or if starvation costs are high and iteration (rework) costs are low.
Fuzzy Markovian segmentation in application of magnetic resonance images
Authors: Su Ruan, Bruno Moretti, Jalal Fadili, Daniel Bloyet
Venue: Computer Vision and Image Understanding (2002)

In this paper, we present a fuzzy Markovian method for brain tissue segmentation from magnetic resonance images. Generally, there are three main brain tissues in a brain dataset: gray matter, white matter, and cerebrospinal fluid. However, due to the limited resolution of the acquisition system, many voxels may be composed of multiple tissue types (partial volume effects). The proposed method aims at calculating a fuzzy membership in each voxel to indicate the partial volume degree, which is statistically modeled. Since our method is unsupervised, it first estimates the parameters of the fuzzy Markovian random field model using a stochastic gradient algorithm. The fuzzy Markovian segmentation is then performed automatically. The accuracy of the proposed method is quantitatively assessed on a digital phantom using an absolute average error and qualitatively tested on real MRI brain data. A comparison with the widely used fuzzy C-means algorithm is carried out to show numerous advantages of our method.
Modeling Train Delays in Urban Networks
Authors: A. Higgins, E. Kozan
Venue: Transportation Science (1998)

The reliability of urban passenger trains is a critical performance measure for passenger satisfaction and ultimately market share. A delay to one train in a peak period can have a severe effect on the schedule adherence of other trains. This paper presents an analytically based model to quantify the expected positive delay for individual passenger trains and track links in an urban rail network. The model specifically addresses direct delay to trains, knock-on delays to other trains, and delays at scheduled connections. A solution to the resultant system of equations is found using an iterative refinement algorithm. Model validation, which is carried out using a real-life suburban train network consisting of 157 trains, shows the model estimates to be on average within 8% of those obtained from a large scale simulation. Also discussed, is the application of the model to assess the consequences of increased scheduled slack time as well as investment strategies designed to reduce delay.
Fast seed computation for reseeding shift register in test pattern compression
Authors: Nahmsuk Oh, Rohit Kapur, T. W. Williams
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

Solving a system of linear equations has been widely used to compute seeds for LFSR reseeding to compress test patterns. However, as chip size is growing, solving linear equations requires a large number of computations that is proportional to n3. This paper proposes a new scan chain architecture and algorithm so that the order of computation is proportional to the number of scan cells in a chip. The new architecture is a methodology change that does not require complex Design-For-Testability (DFT) as proposed in the previous techniques. Instead of solving linear equations, the proposed new seed computation algorithm topologically determines seeds for test vectors. The compression ratio might be slightly lower than the other approaches, but the proposed approach can handle larger designs in a reasonable amount of time. Computation analysis shows that, for 1 million scan cell design, if we assume it takes 1 msec for the proposed technique to compute seeds, it would take more than 14 minutes for other techniques that solve linear equations.
Some observations and remarks on differential operators generated by first-order boundary value problems
Authors: W. N. Everitt, Anthippi Poulkou
Venue: Journal of Computational and Applied Mathematics (2003)

This paper deals with the study of the set of all self-adjoint differential operators which are generated from first-order, linear, ordinary boundary value problems. These operators are defined on a weighted Hilbert function space and are examined as an application of the result obtained by Everitt and Markus in their paper in 1997. An investigation is given so that first-order self-adjoint boundary value problems are transformed to a study of the nature of the spectrum of associated self-adjoint operators. However, the analysis of this paper is restricted to consideration of conditions under which the spectral properties of these operators yield a discrete spectrum, and consequently to the determination of conditions under which the construction of Kramer analytic kernels, from the above boundary value problems, can be accomplished.
A Criterion for Burn-in That Balances Mean Residual Life and Residual Variance
Authors: Henry W. Block, Thomas H. Savits, Harshinder Singh
Venue: Operations Research (2002)

Optimum burn-in times have been determined for a variety of criteria such as mean residual life and conditional survival. In this paper we consider a residual coefficient of variation that balances mean residual life with residual variance. To study this quantity, we develop a general result concerning the preservation ofbathtub distributions. Using this result, we give a condition so that the residual coefficient of variation is bathtub-shaped. Furthermore, we show that it attains its optimum value at a time that occurs after the mean residual life function attains its optimum value, but not necessarily before the change point of the failure rate function.
Using converging methods across disciplines to guide the redesign of a large, information-rich web site
Authors: Susan J. Robinson, Bradford W. Hesse, Abdul R. Shaikh, Mike Coss, Carol Crawford
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

This paper summarizes how differing research methodologies were sequenced during formative evaluation of a large-scale government Web site in order to generate consensus for site redesign and a clear typology of users. Each method was selected by an interdisciplinary research team to bring to the study a convergence of approaches across the fields of human computer interaction, information science, health communication, and social marketing. Researchers can use the study framework in optimizing their own program of organizational and user research, particularly if they are designing and testing large-scale information-rich sites with varied content accessed by a diverse set of users.
Path-Based Clustering for Grouping of Smooth Curves and Texture Segmentation
Authors: Bernd Fischer, Joachim M. Buhmann
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2003)

Perceptual Grouping organizes image parts in clusters based on psychophysically plausible similarity measures. We propose a novel grouping method in this paper, which stresses connectedness of image elements via mediating elements rather than favoring high mutual similarity. This grouping principle yields superior clustering results when objects are distributed on low-dimensional extended manifolds in a feature space, and not as local point clouds. In addition to extracting connected structures, objects are singled out as outliers when they are too far away from any cluster structure. The objective function for this perceptual organization principle is optimized by a fast agglomerative algorithm. We report on perceptual organization experiments where small edge elements are grouped to smooth curves. The generality of the method is emphasized by results from grouping textured images with texture gradients in an unsupervised fashion.
Buffer sizing for minimum energy-delay product by using an approximating polynomial
Authors: Chang Woo Kang, Soroush Abbaspour, Massoud Pedram
Venue: Proceedings of the 13th ACM Great Lakes symposium on VLSI (2003)

This paper first presents an accurate and efficient method of estimating the short circuit energy dissipation and the output transition time of CMOS buffers. Next, the paper describes a sizing method for tapered buffer chains. It is shown that the first-order sizing behavior, which considers only the capacitive energy dissipation, can be improved by considering the short-circuit dissipation as well, and that the second-order polynomial expressions for short-circuit energy improves the accuracy over linear expressions. These results are used to derive sizing rules for buffered chains, which optimize the overall energy-delay product.
Maintaining time-decaying stream aggregates
Authors: Edith Cohen, Martin Strauss
Venue: Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems (2003)

We formalize the problem of maintaining time-decaying aggregates and statistics of a data stream: the relative contribution of each data item to the aggregate is scaled down by a factor that depends on, and is non-decreasing with, elapsed time. Time-decaying aggregates are used in applications where the significance of data items decreases over time. We develop storage-efficient algorithms, and establish upper and lower bounds. Surprisingly, even though maintaining decayed aggregates have become a widely-used tool, our work seems to be the first both to explore it formally and to provide storage-efficient algorithms for important families of decay functions, including polynomial decay.
A capstone unit for a data structures class
Authors: W. Douglas Maurer
Venue: Journal of Computing Sciences in Colleges (2002)

At the end of the semester, students in a data structures class need to know what it has all been about. How are they supposed to use their new knowledge? These questions have prompted us to design a capstone unit, which does for the data structures course what a capstone course does for an undergraduate student's entire four years of study. Our cap-stone unit takes into account resizable stacks, queues, strings, hash tables, and matrices, all of which have certain advantages and disadvantages, compared to their non-resizable counterparts.
An Iterated Dynasearch Algorithm for the Single-Machine Total Weighted Tardiness Scheduling Problem
Authors: Richard K. Congram, Chris N. Potts, Steef L. van de Velde
Venue: INFORMS Journal on Computing (2002)

This paper introduces a new neighborhood search technique, called dynasearch, that uses dynamic programming to search an exponential size neighborhood in polynomial time. While traditional local search algorithms make a single move at each iteration, dynasearch allows a series of moves to be performed. The aim is for the lookahead capabilities of dynasearch to prevent the search from being attracted to poor local optima. We evaluate dynasearch by applying it to the problem of scheduling jobs on a single machine to minimize the total weighted tardiness of the jobs. Dynasearch is more effective than traditional first-improve or best-improve descent in our computational tests. Furthermore, this superiority is much greater for starting solutions close to previous local minima. Computational results also show that an iterated dynasearch algorithm in which descents are performed a few random moves away from previous local minima is superior to other known local search procedures for the total weighted tardiness scheduling problem.
Quincunx fundamental refinable functions and Quincunx biorthogonal wavelets
Authors: Bin Han, Rong-Qing Jia
Venue: Mathematics of Computation (2002)

We analyze the approximation and smoothness properties of quincunx fundamental refinable functions. In particular, we provide a general way for the construction of quincunx interpolatory refinement masks associated with the quincunx lattice in R2. Their corresponding quincunx fundamental refinable functions attain the optimal approximation order and smoothness order. In addition, these examples are minimally supported with symmetry. For two special families of such quincunx interpolatory masks, we prove that their symbols are nonnegative. Finally, a general way of constructing quincunx biorthogonal wavelets is presented. Several examples of quincunx interpolatory masks and quincunx biorthogonal wavelets are explicitly computed.
Metacognitive and computational aspects of chance discovery
Authors: Ruediger Oehlmann
Venue: New Generation Computing (2003)

Chance discovery is concerned with events or situations that affect human decision making; such events or situations are viewed as opportunities or risks. Perspectives are mental representations that describe partial knowledge of a task domain (cognitive perspective) as well as knowledge about other participants (social perspectives). Based on verbal protocols and a computational model of these protocols, it is argued that perspective taking is a suitable strategy to achieve chance discovery. Therefore the cognitive mechanisms underlying this strategy have been investigated and the results implicate metacognition as necessary requirement to achieve chance discovery.
Continuity of DEA Efficiency Measures
Authors: Holger Scheel, Stefan Scholtes
Venue: Operations Research (2003)

Data envelopment analysis (DEA) is a methodology that allows, in one way or other, the assignment of efficiency scores to members of a group of decision-making units. We call an efficiency measure "continuous" if small perturbations of the input-output data cause only small changes in the score. Continuity is a desirable property of an efficiency measure, in particular in the presence of measurement tolerances. Continuity is also desirable from a numerical point of view because the scores are computed by linear programming software.Focusing on convex production possibility sets, we give examples where radial DEA measures fail to be continuous, i.e., they "jump" under small data perturbations. We present necessary and sufficient conditions for continuity in terms of the data and show that these conditions are satisfied for "almost all" data. We also discuss continuity of nonradial measures and identify possible problems of "multistage approaches" to compute mix efficiencies.
Computer literacy: today and tomorrow
Authors: Mark Hoffman, Jonathan Blake
Venue: Journal of Computing Sciences in Colleges (2003)

Computing and technology departments often offer service courses in Computer Literacy that provide the entire academic community with the opportunity to develop skills in the use of computers. These courses have been around for many years, but all too often they have not been updated to reflect new skills and knowledge that students are now bringing with them. In this paper we chronicle the history of teaching Computer Literacy, and discuss its relationship with the broad topic of Information Literacy. We include the description of a course on the Internet taught at Quinnipiac University that serves as a model for an updated Technology Literacy course incorporating both Computer Literacy and Information Literacy.
Towards a Software Change Classification System: A Rough Set Approach
Authors: James F. Peters, Sheela Ramanna
Venue: Software Quality Control (2003)

The basic contribution of this paper is the presentation of two methods that can be used to design a practical software change classification system based on data mining methods from rough set theory. These methods incorporate recent advances in rough set theory related to coping with the uncertainty in making change decisions either during software development or during post-deployment of a software system. Two well-known software engineering data sets have been used as means of benchmarking the proposed classification methods, and also to facilitate comparison with other published studies on the same data sets. Two technologies in computation intelligence (CI) are used in the design of the software change classification systems described in this paper, namely, rough sets (a granular computing technology) and genetic algorithms. Using 10-fold cross validated paired t-test, this paper also compares the rough set classification learning method with the Waikato Environment for Knowledge Analysis (WEKA) classification learning method. The contribution of this paper is the presentation of two models for software change classification based on two CI technologies.
Trapped in Your Own Net? Network Cohesion, Structural Holes, and the Adaptation of Social Capital
Authors: Martin Gargiulo, Mario Benassi
Venue: Organization Science (2000)

This paper explores the tension between two opposite views on how networks create social capital. Network closure (Coleman 1988) stresses the role of cohesive ties in fostering a normative environment that facilitates cooperation. Structural hole theory (Burt 1992) sees cohesive ties as a source of rigidity that hinders the coordination of complex organizational tasks. The two theories lead to opposite predictions on how the structure of an actor's network may affect his ability to adapt that network to a significant change in task environment. Using data from a newly created special unit within the Italian subsidiary of a multinational computer manufacturer, we show that managers with cohesive communication networks were less likely to adapt these networks to the change in coordination requirements prompted by their new assignments, which in turn jeopardized their role as facilitators of horizontal cooperation within a newly created business unit structure. We conclude with a discussion of the trade-off between thesafety of cooperation within cohesive networks and theflexibility provided by networks rich in structural holes.
The Path Restoration Version of the Spare Capacity Allocation Problem with Modularity Restrictions: Models, Algorithms, and an Empirical Analysis
Authors: Jeffery L. Kennington, Mark W. Lewis
Venue: INFORMS Journal on Computing (2001)

This investigation presents a strategy to construct a compact mathematical model of the path-restoration version of the spare capacity allocation problem. The strategy uses a node-arc formulation and combines constraints whenever multiple working paths affected by an edge failure have identical origins or destinations. Another unique feature of this model is the inclusion of modularity restrictions corresponding to the discrete capacities of the equipment used in telecommunication networks.The new model can be solved using a classical branch-and-bound algorithm with a linear-programming relaxation. A preprocessing module is developed, which generates a set of cuts that strengthens this linear programming relaxation. The overhead associated with the cuts is offset by the improved bounds produced. A new branch-and-bound algorithm is developed that exploits the modularity restrictions. In an extensive empirical analysis, a software implementation of this algorithm was found to be substantially faster than CPLEX 6.5.3. For a test suite of 50 problems, each having 50 nodes and 200 demands from a uniform distribution with a small variance, our new software obtained solutions guaranteed to be within 4% of optimality in five minutes of CPU time on a DEC AlphaStation.
Project Scheduling in AND--OR Graphs: A Generalization of Dijkstra's Algorithm
Authors: George M. Adelson-Velsky, Eugene Levner
Venue: Mathematics of Operations Research (2002)

The paper considers a project scheduling problem in weighted directed graphs in which arcs represent operations while nodes are identified with starting and finishing endpoints of the operations; arc lengths represent operation durations. The graphs have two types of nodes--AND-nodes and OR-nodes. The problem is to find the earliest starting times for all operations. This problem generalizes the shortest path problem and the critical path problem. The complexity of the suggested algorithm isO( p' p) wherep'Â Â is the number of arcs entering the AND-nodes andp is the total number of arcs.
Using Markovian decision problems to analyze animal performance in random and variable ratio schedules of reinforcement
Authors: Jérémie Jozefowiez, Jean-Claude Darcheville, Philippe Preux
Venue: Proceedings of the seventh international conference on simulation of adaptive behavior on From animals to animats (2002)

Markovian decision problems are a kind of optimization problems in which an agent must learn how to optimize the amount of reward it can collect during its interaction with its environment. We use them to analyze the task faced by an animal in random and variable schedules of reinforcement. Predictions of the model derived from this analysis are compared to three sets of data obtained in men, rats and pigeons and are contrasted with the ones of its main challenger in psychology, Herrnstein's equation. This reveals the existence of two response strategies in ratio schedules, one which corresponds to our model, the other which is closer to Herrnstein's equation.
Interaction of light and tensor fields
Authors: Xiaoqiang Zheng, Alex Pang
Venue: Proceedings of the symposium on Data visualisation 2003 (2003)

We present three new ways of looking at tensor volumes. All three methods are based on the interaction of simulated light and the tensor field. Conceptually, rays are shot from a certain direction into the tensor volume. These rays are influenced by the surrounding tensor field and bent as they traverse through the volume. The tensor is visualized by both the nature of the bent rays and by the collection of rays deposited on a receiving plate. The former is similar to streamlines, but shows paths of greatest influence by the tensor field. The latter is similar to caustic effects from photon maps, but shows the convergence or divergence of the rays through the tensor volume. We also use the concept of treating the tensor volume as a special lens that distorts an image. Using backward ray tracing through the tensor volume, we generate image distortions that also show internal properties of the tensor field. A key advantage of these techniques is that they can work directly with non-symmetric tensor fields without first decomposing them into components. Color images can also be found in www.soe.ucsc.edu/research/avis/tensorray.html.
A breadth-first companion for the CS I course
Authors: John E. Howland, Mark Lewis, Thomas Hicks, Gerald Pitts
Venue: Journal of Computing Sciences in Colleges (2003)

A breadth-first course, designed to supplement the CSI course, is described. The rationale for the course is given and early experience with the course is described.