ppxscal/embedding_network huggingface dataset:
Parallel Machine Scheduling, Linear Programming, and Parameter List Scheduling Heuristics
Authors: Lap Mui Ann Chan, Ana Muriel, David Simchi-Levi
Venue: Operations Research (1998)

In this paper we consider a class of parallel machine scheduling problems and their associated set-partitioning formulations. We show that the tightness of the linear programming relaxation of these formulations is directly related to the performance of a class of heuristics called parameter list scheduling heuristics. This makes it possible to characterize the worst possible gap between optimal solutions for the scheduling problems and the corresponding linear programming relaxations. In the case of the classical parallel machine weighted completion time model we also show that the solution to the linear programming relaxation of the set-partitioning formulation is asymptotically optimal under mild assumptions on the distribution of job weights and processing times. Finally, we extend most of the results to the time-discretized formulation of machine scheduling problems.
It's all writing: experience using rewriting to learn in introductory computer science
Authors: Brian C. Ladd
Venue: Journal of Computing Sciences in Colleges (2003)

Writing computer programs is writing to communicate with a human and a machine audience. This fact is often lost on students in introductory computer science courses. At St. Lawrence University, an effort has been made to use techniques developed as part of the writing across the curriculum movement such as portfolio evaluation and multiple drafts of written work to improve student outcomes in introductory computer science courses. Motivation and evaluation of the St. Lawrence experience is reported.
Solution algorithms for a nonhomogeneous multi-component inspection model
Authors: W. Wang, A. H. Christer
Venue: Computers and Operations Research (2003)

In this paper, we present three solution algorithms for an established multi-component inspection system model based upon the delay time concept. First, Algorithm 1 is developed for obtaining the system replacement time if the defect arrival process is non-homogeneous. Algorithm 2 is presented as an extension to Algorithm 1 in which the non-constant optimal inspection intervals are also determined. Algorithm 3 is a numerical algorithm for solving an integral equation arising within the model in the case of opportunistic inspection at failures. Finally, an example is given to demonstrate the algorithm set in practice. The proof of the existence and uniqueness of solutions are presented.
Organization Culture As a Complex System: Balance and Information in Models of Influence and Selection
Authors: Kenneth A. Frank, Kyle Fahrbach
Venue: Organization Science (1999)

We define the complex system underlying organizational culture by incorporating the social-psychological principles of balance and information (B-I) into models of influence (changes in attitudes as a function of interaction) and selection (changes in interaction). We identify information based influence as a potential anchor for actors' sentiments so that they are not overwhelmed by normative influence. In the model of selection, we identify the pursuit of information as an important counterbalance to the effect of homophily (interacting with others like oneself). Using the tools of dynamic systems we show how our models generate the full range of equilibria of complex systems. Through simulations we also explore how our system responds to exogenous effects.
Dimensionality of the Strategic Grid Framework: the Construct and its Measurement
Authors: Bhanu Raghunathan, T. S. Raghunathan, Qiang Tu
Venue: Information Systems Research (1999)

The recent dramatic impact of information technology (IT) on organizational performance has necessitated appropriate strategies for managing this organizational resource. IT im- pacts firms in different ways, and management needs a clear and systematic understanding of both the current and future relevance and impact of its IT before selecting management tools and approaches. The strategic grid framework, developed for the purpose of helping man- agement gain this understanding, is one of the most highly recognized and quoted conceptual frameworks in information systems literature. Despite such recognition, valid operational measures of this construct are not available for use in empirical research studies. The research reported in this paper is an attempt to develop and validate operational measures for the dimensions of the strategic grid, with the understanding that the availability of such measures will promote future empirical studies. Data for this study consist of the responses of 231 IS executives to a survey instrument. Operational models of the grid dimensions are specified and the measurement properties of the models are assessed using confirmatory factor analysis (CFA) within the LISREL framework. Measures resulting from the analysis are shown to meet the requirements of rigorous tests of measurement properties. The CFA results also show that the current portfolio dimension of the strategic grid is unidimensional, while the future port- folio dimension has three factors: management support, differentiation, and enhancement.
On the resolution of relative Thue equations
Authors: István Gaál, Michael Pohst
Venue: Mathematics of Computation (2002)

An efficient algorithm is given for the resolution of relative Thue equations. The essential improvement is the application of an appropriate version of Wildanger's enumeration procedure based on the ellipsoid method of Fincke and Pohst.Recently relative Thue equations have gained an important application, e.g., in computing power integral bases in algebraic number fields. The presented methods can surely be used to speed up those algorithms.The method is illustrated by numerical examples.
Hybrid Fiber Coaxial Network Design
Authors: Raymond A. Patterson, Erik Rolland
Venue: Operations Research (2002)

Much interest exists in broadband network services to deliver a variety of products to consumers, such as Internet access, telephony, interactive TV, and video on demand. Due to its cost efficiency, Hybrid Fiber Coaxial (HFC) technology is currently being considered by most Telcos and cable companies as the technology to deliver these products. The topological HFC network design problem as implemented by several major companies is a form of the capacitated tree-star network design problem. We propose a new formulation for this problem and present a heuristic based on hierarchical decomposition of the problem. The proposed solution methodology exploits an Adaptive Reasoning Technique (ART), embedded as a meta-heuristic over specialized heuristics for the subproblems. In this context, we demonstrate the dynamic use of an exact solution technique within ART. The generalizability of the proposed solution methodology is demonstrated by applying it to a second problem, the Traveling Salesman Problem (TSP). Computational results are presented for both the HFC network design problem and the TSP, indicating high-quality solutions expending a very modest computational effort. The proposed solution method is found to be effective, and is shown to be easily adaptable to new problems without much crafting, and as such, has a broad appeal to the general operations research community.
Segmentation of MRI trabecular-bone images using network of synchronised oscillators
Authors: Michal Strzelecki
Venue: Machine Graphics Vision International Journal (2002)

Segmentation of textured images, a very important aspect of visual perception, remains still a challenging task for many image analysis problems. This paper presents a recently emerged segmentation method based on the temporary correlation theory. It proposes an explanation of visual scene analysis performed by human brain. Based on this theory, a network of locally connected synchronised oscillators is proposed for the image segmentation task. This oscillator network can be realised as a VLSI chip, providing very fast image segmentation. For texture description, the Gaussian Markov Random Field model widely used in many texture analysis tasks, is applied. The proposed method is applied to segment MRI images of human foot cross-section in order to detect bone structure. This analysis could be useful in osteoporosis diagnosis, allowing further evaluation of bone microarchitecture. The efficiency of the GMRF approach in bone texture modelling is demonstrated. The oscillator network method is compared with an ANN-based classifier. The segmentation results using both methods are presented and discussed.
A Polynomial Combinatorial Algorithm for Generalized Minimum Cost Flow
Authors: Kevin D. Wayne
Venue: Mathematics of Operations Research (2002)

We propose the first combinatorial solution to the generalized minimum cost flow problem (flow with losses and gains). Despite a rich history dating back to Kantorovich and Dantzig, until now, the only known way to solve the problem in polynomial-time was via general-purpose linear programming techniques. Polynomial combinatorial algorithms were previously known only for the version of our problem without costs. We design the first such algorithms for the version with costs. Our algorithms also find provably good solutions faster than optimal ones, providing the first strongly polynomial approximation schemes for the problem.Our techniques extend to optimize linear programs with two variables per inequality. Polynomial combinatorial algorithms were previously developed for testing the feasibility of such linear programs. We propose the first such methods for the optimization version.
Rate control optimization in embedded wavelet coding
Authors: J. A. Garcia, Rosa Rodriguez-Sánchez, J. Fdez-Valdivia, J. Martinez-Baena
Venue: Pattern Recognition Letters (2003)

To circumvent the lack of knowledge of what measure is more suitable for optimization of the trade-off between image fidelity and coding rate, this paper shall introduce a novel mathematical methodology for rate control by organizing the progressive transmission in accordance with coherence constraints for avoiding forms of behavioral inconsistency. This methodology could be used within a progressive transmission scheme to produce a new compression method (a rational embedded wavelet image coding). Here we compare a new coding scheme based on the proposed rate control technique against the state of art coder in progressive transmission and demonstrate its superior performance based on an objective criterion of evaluation.
Why fuzzy T-equivalence relations do not resolve the Poincaré paradox, and related issues
Authors: Martine De Cock, Etienne Kerre
Venue: Fuzzy Sets and Systems (2003)

In this paper, which is a rejoinder on the comments (Fuzzy Sets and Systems, 133 (2) (2003)), we will answer the questions whether approximate equality should satisfy transitivity, and whether fuzzy T-equivalence relations resolve the Poincaré paradox. Furthermore, we will present an improved definition of resemblance relation and we will investigate its connection with nearness relations.
Product Cycling With Uncertain Yields: Analysis and Application to the Process Industry
Authors: Kumar Rajaram, Uday S. Karmarkar
Venue: Operations Research (2002)

We formulate the dynamic product-cyclingproblem with yield uncertainty and buffer limits to determine how much product to produce at what time to minimize total expected switching, production, inventory storage, and backorder costs. A "restricted" Lagrangian technique is used to develop a lower bound and a model-based Lagrangian heuristic. We also develop an operational heuristic and a greedy heuristic. The operational heuristic has been implemented at seven refineries at Cerestar, Europe's leadingmanuf acturer of wheat-and corn-based starch products in the food-processingindustry . This has already reduced total costs by around 5 percent or $3 million annually at these sites. Tests of the Lagrangian heuristic on data from these refineries during this period have shown the potential to further reduce total costs by at least 2 percent or about $1 million. In addition, the Lagrangian heuristic has provided an objective basis to evaluate the economic impact of several strategic decisions involving issues such as buffer expansion, variability reduction, and product selection.
Sparrow web: group-writable information on structured web pages
Authors: Eric Bier, Ken Pier
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

Sparrow Web is a server-based software tool that supports the creation and customization of group-writable Web pages. Templates in each page define the data schema and layout of that page's group-editable data items. Using different templates, page authors produce Web pages that support many tasks, including task lists, co-authored documents, bibliographies, home pages, faculty directories, and project lists. While lacking the rich UI of dedicated information-sharing applications, it is successful at supporting a variety of groups and tasks because it integrates information-sharing into Web pages, leveraging the affordances of the Web for supporting group work.
Learning power and language expressiveness
Authors: Eric Martin, Arun Sharma, Frank Stephan
Venue: Theoretical Computer Science (2003)

The topic of the present work is to study the relationship between the power of the learning algorithms on the one hand, and the expressive power of the logical language which is used to represent the problems to be learned on the other hand. The central question is whether enriching the language results in more learning power. In order to make the question relevant and nontrivial, it is required that both texts (sequences of data) and hypotheses (guesses) be translatable from the "rich" language into the "poor" one. The issue is considered for several logical languages suitable to describe structures whose domain is the set of natural numbers. It is shown that enriching the language does not give any advantage for those languages which define a monadic second-order language being decidable in the following sense: there is a fixed interpretation in the structure of natural numbers such that the set of sentences of this extended language true in that structure is decidable. But enriching the original language even by only one constant gives an advantage if this language contains a binary function symbol (which will be interpreted as addition). Furthermore, it is shown that behaviourally correct learning has exactly the same power as learning in the limit for those languages which define a monadic second-order language with the property given above, but has more power in case of languages containing a binary function symbol. Adding the natural requirement that the set of all structures to be learned is recursively enumerable, it is shown that it pays off to enrich the language of arithmetics for both finite learning and learning in the limit, but it does not pay off to enrich the language for behaviourally correct learning.
SMAA-2: Stochastic Multicriteria Acceptability Analysis for Group Decision Making
Authors: Risto Lahdelma, Pekka Salminen
Venue: Operations Research (2001)

Stochastic multicriteria acceptability analysis (SMAA) is a multicriteria decision support method for multiple decision makers in discrete problems. In SMAA, the decision makers need not express their preferences explicitly or implicitly. Instead, the method is based on exploring the weight space in order to describe the valuations that would make each alternative the preferred one. Inaccurate or uncertain criteria values are represented by probability distributions from which the method computes confidence factors describing the reliability of the analysis. In this paper we introduce the SMAA-2 method, which extends the original SMAA by considering all ranks in the analysis. In situations where the "elitistic" SMAA may assess large acceptability only for extreme alternatives without sufficient majority support, the more holistic SMAA-2 analysis can be used to identify good compromise candidates. The results are presented graphically. We consider also situations where partial preference information is available. We demonstrate the new method using a real-life decision problem.
Utilizing Forecast Band Refinement for Capacitated Production Planning
Authors: Philip Kaminsky, Jayashankar M. Swaminathan
Venue: Manufacturing Service Operations Management (2000)

We present a model for forecast evolution that captures two notions related to forecasts: (1) forecasts are not exact; (2) forecasts over longer horizons are less certain than those over shorter horizons. We model the forecast of discrete demand as a band defined by the lower and upper bounds on demand, such that future forecasts lie within the current band. We develop a capacitated production planning model for a single product with terminal demand. We develop four heuristics for the problem and characterize their performance. In particular, two of the heuristics are optimal for the no holding-cost case. In our computational study, we analyze the performance of our heuristics and compare them to the optimal solution and to a simple heuristic that simulates common industrial practice using point forecasts. We find that two of our heuristics are very close to the optimal solution (less than 0.5% away from optimal on average under the conditions studied). Further, we consider forecast update patterns with primarily early, intermediate, and late information updates and provide insights on the effect of information update patterns on optimal costs.
Workspace Atlases for the Design of Spherical 3-DOF Serial Wrists
Authors: Xin-Jun Liu, Jinsong Wang, Feng Gao
Venue: Journal of Intelligent and Robotic Systems (2003)

In this paper, the physical model of the solution space of spherical 3-DOF serial wrists is established. The reachable workspaces are classified. The dexterous workspaces for such wrists are investigated based on the rotatability conditions for the spherical 4-bar mechanism. Using the theory of conformal transformation, we obtain plane figures of the reachable and dexterous workspaces. The atlases of the workspaces in the physical model of the solution space are plotted. These results are useful not only for designer overall to understand the relationship between the workspaces and link lengths of spherical 3-DOF serial wrists, but also for the design of the wrists.
Lessons for Success in OR/MS Practice Gained from Experiences in Indian and US Steel Plants
Authors: Goutam Dutta
Venue: Interfaces (2000)

I worked on modeling integrated steel plants in India (as an analyst) and in the USA (as a doctoral student). The following factors influence the success of OR/MS practice: positioning the OR/MS team in operations, not in research and development; selecting the right problems; emphasizing problem solving, not model building; learning from failures; the right academic and practical training; and experience working on the shop floor of a factory. Universities should teach OR as research into operations and emphasize the process of implementation.
Convergence Properties of the Batch Means Method for Simulation Output Analysis
Authors: Natalie M. Steiger, James R. Wilson
Venue: INFORMS Journal on Computing (2001)

We examine key convergence properties of the steady-state simulation analysis method of nonoverlapping batch means (NOBM) when it is applied to a stationary, phi-mixing process. For an increasing batch size and a fixed batch count, we show that the standardized vector of batch means converges in distribution to a vector of independent standard normal variates--a well-known result underlying the NOBM method for which there appears to be no direct, readily accessible justification. To characterize the asymptotic behavior of the classical NOBM confidence interval for the mean response, we formulate certain moment conditions on the components (numerator and denominator) of the associated Student'st-ratio that are necessary to ensure the validity of the confidence interval. For six selected stochastic systems, we summarize an extensive numerical analysis of the convergence to steady-state limits of these moment conditions; and for two systems we present a simulation-based analysis exemplifying the corresponding convergence in distribution of the components of the NOBMt-ratio. These results suggest that in many simulation output processes, approximate joint normality of the batch means is achieved at a substantially smaller batch size than is required to achieve approximate independence; and an improved batch means method should exploit this property whenever possible.
The Fractional Representation Approach to Synthesis Problems: An Algebraic Analysis Viewpoint Part I: (Weakly) Doubly Coprime Factorizations
Authors: A. Quadrat
Venue: SIAM Journal on Control and Optimization (2003)

In this paper, we show how to reformulate the fractional representation approach to analysis and synthesis problems within an algebraic analysis framework. In terms of modules, we give necessary and sufficient conditions so that a system admits (weakly) left/right/doubly coprime factorizations. Moreover, we explicitly characterize the integral domains A such that every plant---defined by means of a transfer matrix whose entries belong to the quotient field of A---admits (weakly) doubly coprime factorizations. Finally, we show that this algebraic analysis approach allows us to recover, on the one hand, the approach developed in [M. C. Smith, IEEE Trans. Automat. Control, 34 (1989), pp. 1005--1007] and, on the other hand, the ones developed in [K. Mori and K. Abe, SIAM J. Control Optim., 39 (2001), pp. 1952--1973; V. R. Sule, SIAM J. Control Optim., 32 (1994), pp. 1675--1695 and 36 (1998), pp. 2194--2195; M. Vidyasagar, H. Schneider, and B. A. Francis, IEEE Trans. Automat. Control, 27 (1982), pp. 880--894; M. Vidyasagar, Control System Synthesis: A Factorization Approach, MIT Press, Cambridge, MA, 1985].
On final coalgebras of continuous functors
Authors: Jirí Adámek
Venue: Theoretical Computer Science (2003)

Continuous endofunctors F of locally finitely presentable categories carry a natural metric on their final coalgebra. Whenever F(0) has an element, this metric is proved to be a Cauchy completion of the initial algebra of F. This is illustrated on the poset of real numbers represented as a final coalgebra of an endofunctor of Pos by Pavlovic´ and Pratt. Under additional assumptions on the locally finitely presentable category, all finitary endofunctors are proved to have a final coalgebra constructed in ω + ω steps of the natural iteration construction.
Characteristic faults and spectral information for logic BIST
Authors: Xiaoding Chen, Michael S. Hsiao
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

We present a new method of built-in-self-test (BIST) for sequential circuits and system-on-a-chip (SOC) using characteristic faults and circuitspecific spectral information in the form of one or more Hadamard coefficients. The Hadamard coefficients are extracted from the test sequences for a small set of characteristic faults of the circuit. By extracting a few characteristic faults from the circuit, we show that detection of these characteristic faults is sufficient in detecting a vast majority of the remaining faults in the circuit. The small number of characteristic faults allows us to reduce the coefficients necessary for BIST. State relaxation is performed on the compacted test sequences to reduce the spectral noise further. Since we are targeting only a very small number of characteristic faults, the execution times for computing the spectra are greatly reduced. Our experimental results show that our new method can achieve high BIST coverage with both lower computational efforts and storage, with very few characteristic faults.