ppxscal/embedding_network huggingface dataset:
Solving a Class of Two-Dimensional Uncapacitated Location-Allocation Problems by Dynamic Programming
Authors: Jack Brimberg, Robert F. Love
Venue: Operations Research (1998)

In this paper we define and analyze a class of two-dimensional location-allocation problems that can be solved with a onedimensional dynamic programming algorithm. We define a criterion that must be satisfied in order that a problem can be classified as having a one-dimensional intrinsic property. An algorithm is developed to test any given problem to see if it possesses this property. We then show that any problem possessing the intrinsic property can be solved by means of an efficient dynamic programming algorithm developed earlier by one of the authors.
Difference, distance and similarity as a basis for fuzzy decision support based on prototypical decision classes
Authors: Jon Williams, Nigel Steele
Venue: Fuzzy Sets and Systems (2002)

The use of prototypical decision classes as a basis for fuzzy decision support is outlined. It is shown that given certain assumptions about the structure of both numeric and non-numeric linguistic variables Trapezoidal Fuzzy Sets can be used to model linguistic terms. In particular the notion of a fuzzy index is introduced to model sets of linguistic terms for which there is no formal measurement scale. The similarity between prototypes and input cases is measured as a function of the difference or 'distance' between fuzzy sets. The difference measure is itself a fuzzy set to reflect the underlying uncertainties in the original linguistic model. Similarity profiles for different decision classes are output as trapezoidal fuzzy sets. The approach can be applied to the rapid development of decision aids using standard business software.
Re-identifying register data by survey data using cluster analysis: an empirical study
Authors: Johann Bacher, Ruth Brand, Stefan Bender
Venue: International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems (2002)

More and more empirical researchers from universities or research centres like to use register or survey data collected by statistical agencies or the social security system, since these data can by used for several empirical studies, e.g. the analysis of special groups or quantitative effects of economic or social policies. Most of the data required have to be (factually) anonymised before they are disseminated to preserve confidentiality. In the area of statistics on households and individuals this path has been pursued in Germany for several years. The transmission of de facto anonymised datafiles has proved to be a good form of co-operation between scientists and statisticians.Factual anonymity of the data depends on the costs and benefits of a potential reidentification. The paper assumes that the intruder only accepts low costs. Therefore he uses a cluster analysis module that is available in a standard statistical software package to re-identify persons. After a description of the method different factors influencing the re-identification risk are studied using German employment statistics (register data) and the German Life History Study (survey data). The factors are: sample fraction and number of (irrelevant) variables. The results show, that the number of identifiable persons is remarkable high. Furthermore it can be confirmed with the cluster analysis that the number of re-identifiable records increases with increasing sampling fraction and that irrelevant variables reduce this number.
Solving Graph Bisection Problems with Semidefinite Programming
Authors: Stefan E. Karisch, Franz Rendl, Jens Clausen
Venue: INFORMS Journal on Computing (2000)

An exact solution method for the graph bisection problem is presented. We describe a branch-and-bound algorithm which is based on a cutting plane approach combining semidefinite programming and polyhedral relaxations. We report on extensive numerical experiments which were performed for various classes of graphs. The results indicate that the present approach solves general problem instances with 80--90 vertices exactly in reasonable time and provides tight approximations for larger instances. Our approach is particularly well suited for special classes of graphs as planar graphs and graphs based on grid structures.
Efficient PDA Synchronization
Authors: David Starobinski, Ari Trachtenberg, Sachin Agarwal
Venue: IEEE Transactions on Mobile Computing (2003)

Modern Personal Digital Assistant (PDA) architectures often utilize a wholesale data transfer protocol known as "slow sync" for synchronizing PDAs with Personal Computers (PCs). This approach is markedly inefficient with respect to bandwidth usage, latency, and energy consumption since the PDA and PC typically share many common records. We propose, analyze, and implement a novel PDA synchronization scheme (CPIsync) predicated upon recent information-theoretic research. The salient property of this scheme is that its communication complexity depends on the number of differences between the PDA and PC, and is essentially independent of the overall number of records. Moreover, our implementation shows that the computational complexity and energy consumption of CPIsync is practical and that the overall latency is typically much smaller than that of slow sync or alternative synchronization approaches based on Bloom filters. Thus, CPIsync has potential for significantly improving synchronization protocols for PDAs and, more generally, for heterogeneous networks of many machines.
The Linux Softsynth roundup
Authors: Dave Phillips
Venue: Linux Journal (2003)

Whether you want to emulate a vintage synthesizer or create a totally new sound, there's software to help make it happen.
Mds Maps for Product Attributes and Market Response: An Application to Scanner Panel Data
Authors: Rick L. Andrews, Ajay K. Manrai
Venue: Marketing Science (1999)

There is theoretical and empirical evidence that consumers have limited cognitive resources and thus cannot maintain direct preferences for each choice alternative on the store shelves. Instead, they likely form their overall preferences for choice alternatives by evaluating the attributes describing each item. Rather than mapping the locations of and preferences for all choice alternatives in a multidimensional space, as is the current practice in marketing research, it is insightful to map the locations of and preferences for the attributes consumers use to evaluate the choice alternatives. The model proposed in this study unifies latent class preference models (choice models or conjoint models) with latent class multidimensional scaling (MDS) analysis. Dimensional restrictions are imposed on latent class preference models such that the locations of attribute levels and market response parameters can be mapped in reduced-dimensionspaces. Interactions between attributes can be graphically examined, which is not feasible with the traditional MDS approach. Also, the effects of price reductions and promotions on the locations of attribute levels can be graphically exam ined. An empirical application with scanner panel data shows the capabilities and limitations of the proposed model. In addition to the managerial insights provided by the model, it is also much more parsimonious than existing methods, and it forecasts holdout choices significantly better. In the empirical application, a model with two-dimensional attribute maps has 50 fewer parameters than the best unrestricted latent class choice model, yet the fit is comparable. The predictive performance of our model is shown to be superior to that of latent class MDS approaches and latent class conjoint approaches.
Quantity Flexibility Contracts and Supply Chain Performance
Authors: A. A. Tsay, W. S. Lovejoy
Venue: Manufacturing Service Operations Management (1999)

The Quantity Flexibility (QF) contract is a method for coordinating materials and infor- mation flows in supply chains operating under rolling-horizon planning. It stipulates a maximum percentage revision each element of the period-by-period replenishment schedule is allowed per planning iteration. The supplier is obligated to cover any requests that remain within the upside limits. The bounds on reductions are a form of minimum purchase commitment which discourages the customer from overstating its needs. While QF contracts are being implemented in industrial practice, the academic literature has thus far had little guidance to offer a firm interested in structuring its supply relationships in this way. This paper seeks to address this need, by developing rigorous conclusions about the behavioral consequences of QF contracts, and hence about the implications for the performance and design of supply chains with linkages possessing this structure. Issues explored include the impact of system flexibility on inventory characteristics and the patterns by which forecast and order variability propagate along the supply chain. The ultimate goal is to provide insights as to where to position flexibility for the greatest benefit, and how much to pay for it.
Myopic Heuristics for the Random Yield Problem
Authors: Srinivas Bollapragada, Thomas E. Morton
Venue: Operations Research (1999)

We consider a single item periodic review inventory problem with random yield and stochastic demand. The yield is proportional to the quantity ordered, with the multiplicative factor being a random variable. The demands are stochastic and are independent across the periods, but they need not be stationary. The holding, penalty, and ordering costs are linear. Any unsatisfied demands are backlogged. Two cases for the ordering cost are considered: The ordering cost can be proportional to either the quantity ordered (e.g., in house production) or the quantity received (e.g., delivery by an external supplier). Random yield problems have been addressed previously in the literature, but no constructive solutions or algorithms are presented except for simple heuristics that are far from optimal. In this paper, we present a novel analysis of the problem in terms of the inventory position at the end of a period. This analysis provides interesting insights into the problem and leads to easily implementable and highly accurate myopic heuristics. A detailed computational study is done to evaluate the heuristics. The study is done for the infinite horizon case, with stationary yields and demands and for the finite horizon case with a 26-period seasonal demand pattern. The best of our heuristics has worst-case errors of 3.0% and 5.0% and average errors of 0.6% and 1.2% for the infinite and finite horizon cases, respectively.
Optimizing Over the Efficient Set Using a Top-Down Search of Faces
Authors: Serpil Sayin
Venue: Operations Research (2000)

The problem of optimizing a linear function over the efficient set of a multiple objective linear programming problem is studied. The decomposition of the efficient set into efficient faces is used as the basis of a search-based algorithm to solve this problem. The faces of the feasible region are characterized by the set of constraints that hold as equality in that face. The search is conducted over the indices of the constraints in a way that explores faces of possibly higher dimension first. Computational tests are performed to establish the behavior of the algorithm when the objective function is built according to different schemes that have received attention in the literature. The results indicate that different objective function types may lead to varying computation time requirements. In general, computational requirements of the algorithm increase significantly with problem size. A heuristic modification of the algorithm is proposed to solve large problems within reasonable time limits. Tests to measure the quality of the heuristic solutions show that the heuristic approach constitutes a practical alternative for finding good solutions for the problem.
Critical factors in the development of executive systems: leveraging the dashboard approach
Authors: Frédéric Adam, Jean-Charles Pomerol
Venue: Decision making support systems: achievements, trends and challenges for (2002)

Based on the Rockart's critical success factor (CSF) approach, this chapter puts forward a practical method to guide the development of executive information systems (EIS) in organizations. This method extends the current theory of EIS by using the concept of the dashboard of information to show how an enterprise-wide approach to the development of more effective decision support for managers can deliver tangible benefits without requiring the time consuming and single-decision focus of the traditional development methods. This method also attempts to leverage the latest computing technologies now available for the development of such systems, notably graphical user interfaces (GUI), data warehousing (DW) and OLAP. The proposed approach is illustrated by examples of dashboard developments, which show how managers should carry out the analysis and development of such a system in their own organizations, business units or functional areas.
Lagrangian Solution Techniques and Bounds for Loosely Coupled Mixed-Integer Stochastic Programs
Authors: Samer Takriti, John R. Birge
Venue: Operations Research (2000)

Many production problems involve facility setups that lead to integer variables, production decisions that are continuous, and demands that are likely to be random. While these problems can be quite difficult to solve, we propose a model and an efficient solution technique for this basic class of stochastic mixed-integer programs. We use a set of scenarios to reflect uncertainty. The resulting mathematical model is solved using Lagrangian relaxation. We show that the duality gap of our relaxation is bounded above by a constant that depends on the cost function and the number of branching points in the scenario tree. We apply our technique to the problem of generating electric power. Numerical results indicate significant savings when the stochastic model is used instead of a deterministic one.
Throughput-driven IC communication fabric synthesis
Authors: Tao Lin, Lawrence T. Pileggi
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

As the scale of system integration continues to grow, the on-chip communication becomes the ultimate bottleneck of system performance and the primary determinant of system architecture. In this paper we propose a throughput-driven synthesis methodology for on-chip communication fabrics based on optimized bus models. Compared with traditional delay-driven, wire-by-wire planning methods, the throughput-driven methodology provides a feasible and accurate system-level solution to address delay and congestion problems simultaneously during earlyphase design planning. Unlike the conventional methods which are based on rather inaccurate RC models and simplistic delay metrics, in our methodology the communication fabrics are characterized in terms of realistic Partial Element Equivalent Circuits (PEEC) extracted from the multi-layer interconnects and transistor level transient analysis via SPICE-like tools. The characterized models facilitate a flexible interconnect fabric optimization engine that can be embedded into a system planner for throughput-driven synthesis. Furthermore, engineering trade-offs considering repeater area and interconnect power consumption are further considered as part of this methodology.
Global attractor for the Cahn--Hilliard/Allen--Cahn system
Authors: Maria Gokieli, Akio Ito
Venue: Nonlinear Analysis: Theory, Methods Applications (2003)

We study the coupled Cahn-Hilliard/Allen-Cahn problem with constraints, which describes the isothermal diffusion-driven phase transition phenomena in binary systems. Our aim is to show the existence-uniqueness result and to construct the global attractor for the related dynamical system.
Time-Indexed Formulations for Machine Scheduling Problems: Column Generation
Authors: J.M. Van Den Akker, C.A.J. Hurkens, M.W.P. Savelsbergh
Venue: INFORMS Journal on Computing (2000)

Time-indexed formulations for machine scheduling problems have received a great deal of attention; not only do the linear programming relaxations provide strong lower bounds, but they are good guides for approximation algorithms as well. Unfortunately, time-indexed formulations have one major disadvantage--their size. Even for relatively small instances the number of constraints and the number of variables can be large. In this paper, we discuss how Dantzig-Wolfe decomposition techniques can be applied to alleviate, at least partly, the difficulties associated with the size of time-indexed formulations. In addition, we show that the application of these techniques still allows the use of cut generation techniques.
The Multilevel and Multifaceted Character of Computer Self-Efficacy: Toward Clarification of the Construct and An Integrative Framework for Research
Authors: George M. Marakas, Mun Y. Yi, Richard D. Johnson
Venue: Information Systems Research (1998)

Despite the recent empirical interest and advances in research with regard to the construct of computer self-efficacy (CSE), the results obtained to date have, in some cases, been either equivocal or contradictory. We suggest that such results may be attributable to a general lack of attention to the dynamic, multileveled, and multifaceted nature of the computer self-efficacy construct. We offer examples from the extant CSE literature suggesting weaknesses in existing measures of the construct as well as issues associated with manipulations and the need for control of antecedent and consequent factors directly associated with CSE. The objectives of this paper are: (1) to provide a thorough review of the extant literature related to CSE; (2) to present an integrated model of empirical findings, constructed from a wide variety of disciplines, that comprehensively defines the multifaceted nature of task-specific CSE in terms of its antecedent, consequent, and moderating factors; (3) to present a conceptual model of CSE at the general versus task-specific level; and (4) to use the two models of CSE to proffer guidelines for both measurement and manipulation of the construct. Through our review of the CSE literature, we offer several thoughts regarding the nature of the empirical results obtained to date. The combined objectives serve as a basis for establishing a foundation upon which future research investigating the CSE construct can be based.
User-cognizant multidimensional analysis
Authors: Sunita Sarawagi
Venue: The VLDB Journal &mdash; The International Journal on Very Large Data Bases (2001)

Our goal is to enhance multidimensional database systems with a suite of advanced operators to automate data analysis tasks that are currently handled through manual exploration. In this paper, we present a key component of our system that characterizes the information content of a cell based on a user's prior familiarity with the cube and provides a context-sensitive exploration of the cube. There are three main modules of this component. A Tracker, that continuously tracks the parts of the cube that a user has visited. A Modeler, that pieces together the information in the visited parts to model the user's expected values in the unvisited parts. An Informer, that processes user's queries about the most informative unvisited parts of the cube. The mathematical basis for the expected value modeling is provided by the classical maximum entropy principle. Accordingly, the expected values are computed so as to agree with every value that is already visited while reducing assumptions about unvisited values to the minimum by maximizing their entropy. The most informative values are defined as those that bring the new expected values closest to the actual values. We believe and prove through experiments that such a user-in-the-loop exploration will enable much faster assimilation of all significant information in the data compared to existing manual explorations.
Cubic spline collocation for Volterra integral equations
Authors: Peeter Oja, Darja Saveljeva
Venue: Computing (2002)

In the standard step-by-step cubic spline collocation method for Volterra integral equations an initial condition is replaced by a not-a-knot boundary condition at the other end of the interval. Such a method is stable in the same region of collocation parameter as in the step-by-step implementation with linear splines. The results about stability and convergence are based on the uniform boundedness of corresponding cubic spline interpolation projections. The numerical tests given at the end completely support the theoretical analysis.
Open source software and computer science education
Authors: Keith J. O'Hara, Jennifer S. Kay
Venue: Journal of Computing Sciences in Colleges (2003)

We investigate the role of open source software in computer science education. We begin with a brief tutorial on open source software including a description of four popular open source licenses. Next we discuss the use of open source software in education. Finally, we focus on the use of open source software in computer science education.
Aligning two fragmented sequences
Authors: Vamsi Veeramachaneni, Piotr Berman, Webb Miller
Venue: Discrete Applied Mathematics (2003)

Upon completion of the human and mouse genome sequences, world-wide sequencing capacity will turn to other complex organisms. Current strategies call for many of these genomes to be incompletely sequenced. That is, holes will remain in the known sequence, and the relative order and orientation of the known sequence fragments may not be determined. Sequence comparison between two genomes of this sort may allow some of the fragments to be oriented and ordered relative to each other by computational means. We formalize this as an optimization problem, show that the problem is MAX-SNP hard, and develop a polynomial time algorithm that is guaranteed to produce a solution whose score is within a factor 3 of optimal.
Glueing and orthogonality for models of linear logic
Authors: Martin Hyland, Andrea Schalk
Venue: Theoretical Computer Science (2003)

We present the general theory of the method of glueing and associated technique of orthogonality for constructing categorical models of all the structure of linear logic: in particular we treat the exponentials in detail. We indicate simple applications of the methods and show that they cover familiar examples.
Restoration of coastal wetlands and management of wastewater disposal
Authors: N. M. Ismail
Venue: Development and application of computer techniques to environmental studies (2002)

A study has been conducted to arrive at the most cost-effective and environmentally acceptable solution to the discharge of partially treated wastewater into coastal wetlands, lakes and offshore waters, where funding for complete conventional treatment plans has either been severed or inadequate.Field data of water-quality parameters for effluents discharged out of wastewater oxidation ponds and constructed wetlands have been reviewed and analyzed.The case studies reported herein are those of natural treatment plants in the USA (California) and in the Middle East (Jordan). The results of the extensive work conducted at the natural treatment plant in Jordan and on the effluents discharged into the Zerka river indicate the viability of using treated wastewater for irrigation in the Jordan valley. The findings of the study suggest an appropriate and alternative solution to Alexandria's current disposal of primary-treated wastewater into Lake Maryout. The recommended scheme comprises an integrated system of oxidation ponds and a constructed wetland in the Maryout Valley prior to disposal in the lake or reuse for irrigation. This integrated system would provide a solution to cope with water scarcity and river basin management.