ppxscal/embedding_network huggingface dataset:
Improving Generator Availability at a Western United States Electric Power Plant
Authors: Gerrit H. Van Bruggen, Ale Smidts, Berend Wierenga, Al Sweetser
Venue: Interfaces (1998)

On several occasions, as an operations research analyst, I have been asked to work on project teams formed to address some particular problem, even though no specific need for operations research abilities had been identified at the outset. In this case, the Public Service Company of Colorado asked me to work on a project team formed to improve the availability of a coal-fired steam generator at an electric power plant. Plant personnel had been trying unsuccessfully for several years to reduce system downtime. I recognized that the plant could make immediate improvements by reducing the duration of breakdowns rather than their frequency. The company initially estimated the payoff for these improvements at $544,000 annually, but has since revised it upward, and it may be as high as $2 million annually. The insights that produced these process improvements were possible because of the hands-on approach to problem solving taught at Colorado School of Mines.
Families of valued sets as media
Authors: Alexander Dukhovny, Sergei Ovchinnikov
Venue: Technologies for constructing intelligent systems: Tasks (2002)

It is shown that the family of all valued sets on a finite universe with values in a finite linear order is a medium. Stochastic properties of these media are investigated.
Incremental requirement specification for evolving systems
Authors: Bengt Jonsson, Tiziana Margaria, Gustaf Naeser, Jan Nyström, Bernhard Steffen
Venue: Nordic Journal of Computing (2001)

We propose a technique for hierarchically structuring requirement specifications in a way that simplifies change management. Our technique decomposes the process of requirement specification and validation. Specifications, added or modified incrementally on various levels of abstraction, can directly be subject to automatic verification, thus providing early feedback concerning design decisions or the impact of adding or changing service functionality. Thus it is possible to maintain consistency between (incomplete) requirement specifications and the underlying evolving implementation model.
Batch Construction Heuristics and Storage Assignment Strategies for Walk/Rideand Pick Systems
Authors: Robert A. Ruben, F. Robert Jacobs
Venue: Management Science (1999)

The retrieval of items from storage is a chore faced by virtually every business concern. Walk/ride and pick systems are a popular method for performing this chore in many applications. When retrieval requests consist of multiple items, order pickers must travel to numerous storage locations to complete each order. When these requests are made in sufficient volume, a method of order retrieval known as batch picking is often used. Batch picking is a popular approach in the mail-order industry and is employed in industrial settings such as tool cribs and in warehouses, which service assembly line operations. Batch construction heuristics are developed and tested under three strategies for assigning storage space to individual items that have been suggeste d in the literature. Our results are derived from the simulation of a single hypothetical warehouse model. Specifically, we employ a model that is square in travel distance and assume the walk and pick method of order retrieval with sequential one-way travel. Sensitivity analysis is performed on workforce level and batch size. Our results indicate that the methods used for constructing batches of orders and for assigning storage space to individual items can significantly impact order retrieval efforts in warehouses of this type.
Optimal Offer Construction in Electricity Markets
Authors: E. J. Anderson, A. B. Philpott
Venue: Mathematics of Operations Research (2002)

In this paper we study strategies for generators making offers into electricity markets in circumstances where both the demand for electricity and the behaviour of competing generators is unknown but can be represented by a probability distribution. Given this probability distribution, we derive necessary optimality conditions for a broad class of supply offer curves. We show how these conditions can be used to construct an optimal solution for a simple example. We also consider the case in which a generator is restricted in the number of prices at which power can be offered.
Performance visualization for distributed shared memory systems
Authors: James E. Lumpp, Kuppuswamy Sivakumar, Christopher Diaz, James N. Griffioen
Venue: Virtual shared memory for distributed architectures (2001)

Distributed shared memory (DSM) systems allow programmers to use a shared memory programming model on distributed systems. However, DSM systems present new challenges to performance evaluation and debugging. While programmers write programs with a shared memory model using shared variables and shared memory synchronization primitives to coordinate processes, most performance problems arise from the implementation of these abstractions with messages. Because the DSM abstraction hides the underlying message passing, it is difficult to identify the sources of performance problems. We have developed an instrumentation system and performance evaluation techniques for DSM systems that correlate message passing behavior in the lower levels of a DSM system with the higher-level shared memory programming abstractions. We have developed a prototype tool called Xunify to demonstrate the feasibility of such an approach. Xunify provides graphical animations of DSM programs at three distinct levels and offers a powerful event filtering facility capable to help show system behavior corresponding to specific DSM constructs.
Aggregation techniques for statistical confidentiality
Authors: Josep Domingo-Ferrer, Vicenç Torra
Venue: Aggregation operators: new trends and applications (2002)

This chapter describes microaggregation, a technique for statistical confidentiality that uses aggregation operators. We describe the goals of statistical confidentiality and its application to continuous and categorical data. We show the application of the method to a small publicly available data set. The chapter finishes by reviewing some of the practical problems of the application of microaggregation to statistical disclosure control.
On a second order parallel variable transformation approach
Authors: Li-Ping Pang, Zun-Quan Xia, Li-Wei Zhang
Venue: The Korean Journal of Computational Applied Mathematics (2003)

In this paper we present a second order PVT (parallel variable transformation) algorithm converging to second order stationary points for minimizing smooth functions, based on the first order PVT algorithm due to Fukushima (1998). The corresponding stopping criterion, descent condition and descent step for the second order PVT algorithm are given.
Issues for library management when implementing large-scale programmatic change
Authors: Kathy Arsenault, Ardis Hanson, Joan Pelland, Derrie Perez, Beverly Shattuck
Venue: Building a virtual library (2003)

Change, by its very nature, is unpredictable, and often unmanageable, yet an organization's success depends on an ability to predict and control change in some way. To derive maximum benefit from new opportunities and to avoid reactive situations, it is essential to manage organizational change. Further, as change accelerates, the more difficult and stressful it is to manage.The proliferation of change management literature in the library and information field indicates that these issues are becoming increasingly important as more academic libraries develop a virtual presence (Higuchi, 1990; Lee, 1993; Riggs, 1997; Meyer, 1997; Nozero & Vaughn, 2000). Nearly a decade ago, Dougherty and Dougherty (1993) observed that the current rate of change in the information field was higher than ever before, while libraries' ability to respond quickly and decisively had never been more constrained. Academic libraries, like other organizations, must respond proactively to their changing environment in order to take advantage of the opportunities for increasing their visibility, restructuring to meet the needs of their users, and achieving their objective of remaining the preeminent source of information within the academy.This chapter begins with an overview of the theoretical perspectives of change. Using Burke, Church and Waclawski's (1993) Managing Change model, the authors will discuss the structure of change, the culture of change, and the individual response to change within a case study framework.
Research Report: Increasing Returns to Information Technology
Authors: Stephan Kudyba, Romesh Diwan
Venue: Information Systems Research (2002)

This work analyzes firm-level investment in information technology and corresponding productivity through the use of a production function over the period from 1995-1997. The results are then compared to previous studies that utilized similar data and methodologies to compare productivity estimates over time. The analysis indicates that investment in IT enhances productivity over the period in question and has illustrated increasing returns over time. These findings are supported by the corresponding empirical analysis which yielded IT capital coefficients in a production function of (0.12, 0.16, 0.18) and IT flow coefficients in a similar function of (0.17, 0.24, 0.22) for the years 1995, 1996, and 1997, respectively. These results reflect the change in firm output given a one-percent change in the natural log of dollars invested in IT capital and flow, and are statistically significant.
Connectivity on complete lattices: new results
Authors: Ulisses Braga-Neto, John Goutsias
Venue: Computer Vision and Image Understanding (2002)

The notion of connectivity is very important in image processing and analysis, and particularly in problems related to image segmentation. It is well understood, however, that classical notions of connectivity, including topological and graph-theoretic notions, are not compatible with each other. This motivated G. Matheron and J. Serra to develop a general framework of connectivity, which unifies most classical notions, circumvents incompatibility issues, and allows the construction of new types of connectivity for binary and grayscale images. In this paper, we enrich this theory of connectivity by providing several new theoretical results and examples that are useful in image processing and analysis. In particular, we provide new results on the semi-continuity behavior of connectivity openings, we study the reconstruction operator in a complete lattice framework, and we extend some known binary results regarding reconstruction to this framework. Moreover, we study connectivities constructed by expanding given connectivities by means of clustering operators and connectivities constructed by restricting given connectivities by means of contraction operators.
Putting non-functional requirements to good use
Authors: Martin L. Barrett
Venue: Journal of Computing Sciences in Colleges (2002)

Non-functional requirements are often ignored or given little importance in the curriculum. This is unfortunate, because there are many interesting and important learning opportunities to be gained from a serious consideration of them. In addition, there is currently no separate document associated with these requirements. This paper introduces the Performance Case to remedy this situation.Performance Cases are closely modeled on Use Cases that are used for documenting functional requirements. Finally, several enrichment exercises using Performance Cases are given.
A Whole-Link Travel-Time Model with Desirable Properties
Authors: Malachy Carey, Y. E. Ge, Mark McCartney
Venue: Transportation Science (2003)

In network models for dynamic traffic assignment the link travel times are often described by "whole-link" models. In particular, they have been expressed as a function of the number of vehicles currently on the link. Such whole-link models are useful approximations and make the network model tractable when flows and travel times are varying over time. Here we propose an alternative whole-link model to approximate travel times. For a vehicle entering a link at timet, we let the link travel time be a function of a weighted average of the inflow rate at the time it enters and the outflow rate at the time it exits. We show that this model ensures first-in-first-out and has other desirable properties. We indicate computational methods for solving the model, apply it to various patterns of inflows, and compare the numerical results with two alternative whole-link models.
Non-linear factor analysis (NLFA) with feedforward networks performs non-linear data reduction with extraction of linear scores
Authors: Seppo Karrila
Venue: Second international workshop on Intelligent systems design and application (2002)

While Principal Component Analysis (PCA) is a well-known method for quantifying the redundancy between observed numerical values, it cannot effectively reduce non-linear relationships between these variables. Non-Linear Factor Analysis (NLFA) is a novel auto-associative method for data reduction, which extracts linear features to provide an easily documented encoding, while the decoding mapping is non-linear. NLFA can be implemented with standard feedforward networks if the user has control over the network configuration; many commercial packages provide the functionality needed.This type of auto-association for data reduction has not been studied or reported earlier in any depth. The (feature selection -type) encoding-decoding pair (x, y(x)) ↦ x ↦ (x, y(x)), where x and y may be vectors and y(•) is a non-linear mapping, is a natural example of linear encoding whose inverse (decoding) is non-linear. Linear feature extraction with non-linear decoding can be viewed as a generalization of feature selection - a heuristic discussion suggests this type of data reduction is effective for a wide range of practical non-linear problems. The level of effectiveness is discussed through Linearly Reducible Intrinsic Dimensionality (LRID), which is defined for continuous error-free data in a manifold; the NLFA method estimates this value from representative (typically inaccurate) discrete data.The numerically found linear encoding can be used to improve (post-process) the decoding in a manner that corresponds to a decoding network with bypass connections, and reduces the reconstruction error for the discrete data. This improved NLFA ensures that the composite function performing encoding followed by decoding, p=gof, is idempotent, p2=p, which ensures consistent results when the mapping p is viewed as "a projection to corrected values" that are in the range of the decoding g.The data reduction capacity of NLFA is between conventional PCA and the fully non-linear Kramer's NLPCA; the relationship of these three methods is discussed. Reference is provided to a separate publication, which contains numerical application examples of the basic (non-improved) NLFA.
Supporting collaborative design
Authors: Wang Yanjie, Chris George
Venue: Proceedings of the IFIP TC6/WG6.1 Fifth International Conference on Formal Methods for Open Object-Based Distributed Systems V (2002)

Collaborative systems provide a rich but potentially chaotic environment for their users. During the collaborative design process, when different users share a common object, concurrency control is necessary to keep the shared object consistent. In this paper, we have developed a model for supporting concurrency control in CSCW applications. We also include version control, allowing versions of both the design entities and their relationships. Consistency in collaborative design is important: the use of the RAISE formal method provides confidence that the transaction mechanism fulfils the consistency requirements. We also generate a prototype from the specification, with a graphical output to show the structure of the design, the entities available, and who is currently locking what.
Project in applied software engineering
Authors: Dennis S. Martin
Venue: Journal of Computing Sciences in Colleges (2003)

Many schools are meeting a community need by offering a Master's degree for software developers who either did not have an undergraduate major in software development or who had one before the current emphasis on project management techniques was standard. Such a program may also attract students who have had a more recent undergraduate program but who need graduate work to keep up with the field. The author teaches the core two-semester sequence in such a program and has found a strategy that addresses the needs of such a mixed audience. The first semester course described here is designed to be valuable even for a student who does not take the second semester. Although writing intensive, this course has been successfully used in a class that included a number of students for whom English was not a first language.
Color consistency for digital multi-projector stereo display systems: the HEyeWall and the Digital CAVE
Authors: W. Kresse, D. Reiners, C. Knöpfle
Venue: Proceedings of the workshop on Virtual environments 2003 (2003)

Digital projectors have a significant advantage over CRTs for IPT setups: brightness. But they also have a number of disadvantages, one of which is color consistency. This problem is exacerbated when using the Infitec method for stereo separation, which in itself has some strong advantages for CAVE and tiled wall setups. In this paper we will describe a method for color and brightness correction of multi-projector display systems. The method itself is used in two new projection systems, which are currently under construction at Fraunhofer-IGD: The HEyewall and the Digital CAVE. The HEyeWall is the first stereo capable tiled display worldwide. The Digital CAVE is the first CAVE with digital projectors and stereo separation based on Infotec(tm). In this paper we present these new IPTs in more detail and also present our experience with digital projectors.To calibrate all the involved projectors photometric measurements of the different projectors are used to calculate a common gamut in a linear colorspace. Input colors are mapped into this gamut and from there mapped into the individual projector's colorspace. This method allows to adjust the rendering output of two or more projectors with different color gamuts in such a way that the projected images are photometrically calibrated. Since the correction has to be done for each pixel, a straightforward implementation would be very slow and far away from realtime. Consequently we will outline a method how to improve performance and overcome this limitation.
Small meshes of curves and their role in the analysis of optimal meshes
Authors: Gelasio Salazar
Venue: Discrete Mathematics (2003)

An (m,n)-mesh is a pair (B,R) of families of closed curves in the plane, of sizes m and n, respectively, such that each curve in B intersects each curve in R. As Richter and Thomassen observed, the minimum number i*(m,n) of intersections in an (m,n)-mesh is closely related to the crossing number of the Cartesian product Cm × Cn. In their work on intersections of curve systems, Shahrokhi et al. proved general lower bounds for i*(m,n), and showed that the exact knowledge of i*(k,k) yields considerably good bounds for i*(m,n) if m,n ≥ k, and m is very close to n. Our aim in this paper is to show that comparable (slightly improved) bounds can be obtained by a careful analysis of the nature of the intersections in certain very small (3, k)-meshes. The advantage of this approach is that the analysis of (3, k)-meshes seems to be a far easier task than the exact computation of i*(k,k) for large values of k.
Algebraic methods for optimization problems
Authors: Richard Bird, Jeremy Gibbons, Shin-Cheng Mu
Venue: Algebraic and coalgebraic methods in the mathematics of program construction (2002)

We argue for the benefits of relations over functions for modelling programs, and even more so for modelling specifications. To support this argument, we present an extended case study for a class of optimization problems, deriving efficient functional programs from concise relational specifications.
High-Level Cache Modeling for 2-D Discrete Wavelet Transform Implementations
Authors: Y. Andreopoulos, P. Schelkens, G. Lafruit, K. Masselos, J. Cornelis
Venue: Journal of VLSI Signal Processing Systems (2003)

The main implementations of the 2-D binary-tree discrete wavelet decomposition are theoretically analyzed and compared with respect to data-cache performance on instruction-set processor-based realizations. These implementations include various image-scanning techniques, from the classical row-column approach to the block-based and line-based methods, which are proposed in the framework of multimedia-coding standards. Analytical parameterized equations for the prediction of data-cache misses under general realistic assumptions are proposed. The accuracy and the consistency of the theory are verified through simulations on test platforms and a comparison is made with the results from a real platform.
An efficient and evolutionary hierarchical modeling and simulation approach
Authors: Paul Bisgambiglia, Marielle Delhom, Jean-François Santucci
Venue: Systems Analysis Modelling Simulation (2002)

Modeling and simulation have taken a preponderant place in the analysis and design of complex systems. The general environment we present in this paper provides a set of tools intended to make easier the creation and the simulation of evolving models. The originality of the approach is layed on the one hand in the combination of a hierarchical modeling and a discrete event simulation formalism, and on the other hand the implementation of object-oriented concepts during the realization phase. After a description of the existing works directly related to our approach, we introduce the basic modeling concepts and the defined object-oriented simulation architecture. Then, we propose a concrete application concerning the analysis of one complex natural system "the hydrologic behavior of the catchment basin". This study ends with the presentation of results obtained from a set of real data.
Performance Analysis of Split-Case Sorting Systems
Authors: M. Eric Johnson, Russell D. Meller
Venue: Manufacturing Service Operations Management (2002)

Split-case sorting systems are used in many retail supply chains where items must be distributed in less-than-case quantities, such as orders shipped directly to customers by catalogers and e-tailers or shipments made in less-than-case quantities from a distribution center to a retail store. These systems are particularly effective in order-packing systems where the same item is needed for multiple orders. Items are inducted into a circular sorting conveyor system one unit at a time and then delivered to an order-packing bin designated for a particular customer or retail store. We develop analytical performance models that incorporate the stochastic operating conditions faced by these systems. Our model allows system designers to predict the sorting capacity for different system configurations. More importantly, we use the model to develop insight into the system design and operation.