ppxscal/embedding_network huggingface dataset:
A Branch-and-Cut Procedure for the Vehicle Routing Problem with Time Windows
Authors: Jonathan F. Bard, George Kontoravdis, Gang Yu
Venue: Transportation Science (2002)

This paper addresses the problem of finding the minimum number of vehicles required to visit a set of nodes subject to time window and capacity constraints. The fleet is homogeneous and is located at a common depot. Each node requires the same type of service. An exact method is introduced based on branch and cut. In the computations, ever increasing lower bounds on the optimal solution are obtained by solving a series of relaxed problems that incorporate newly found valid inequalities. Feasible solutions or upper bounds are obtained with the help of greedy randomized adaptive search procedure (GRASP). A wide variety of cuts is introduced to tighten the linear programming (LP) relaxation of the original mixed-integer program. To find violated cuts, it is necessary to solve a separation problem. A substantial portion of the paper is aimed at describing the heuristics developed for this purpose. A new approach for obtaining feasible solutions from the LP relaxation is also discussed. Numerical results for standard 50- and 100-node benchmark problems are reported.
The Holding Problem with Real-Time Information Available
Authors: Xu Jun Eberlein, Nigel H. M. Wilson, David Bernstein
Venue: Transportation Science (2001)

Holding is one of the most commonly used real-time control strategies in transit operations. Given a transit network and its operations plan, the holding problem is to decide at a given time at a control station, which vehicle is to be held and for how long, such that the total passenger cost along the route is minimized over a time period. Previous research on the holding problem has always assumed no real-time information available. Such an assumption not only poses great difficulties in solving the problem, but also limits practical applications in a real-time, dynamic operations environment. In this paper we formulate the holding problem as a deterministic quadratic program in a rolling horizon scheme, and develop an efficient solution algorithm to solve it. Using headway data collected by an automated system, we tested the algorithm and evaluated the impact of the resulting holding policies. Important and interesting properties of the holding solution, obtained from both theoretical and computational analyses, are presented.
Architecture of a shared-image electronic whiteboard in telemedicine
Authors: Michael Fromme, Helmut Pralle
Venue: Future Generation Computer Systems (2003)

In this paper we present a software whiteboard for multimedia conferences. The whiteboard is specialised to load and share high-resolution colour images while using colour management functions to provide an accurate colour representation. The whiteboard is used in the telemedicine project INTER-FACE, which builds a virtual environment for tele-consultations between specialists in pre-operative treatment and the planning of the cranio-maxillofacial surgery for patients with facial abnormalities.
Diagnosis with Dependent Symptoms: Bayes Theorem and the Analytic Hierarchy Process
Authors: Thomas L. Saaty, Luis G. Vargas
Venue: Operations Research (1998)

Judgments are needed in medical diagnosis to determine what tests to perform given certain symptoms. For many diseases, what information to gather on symptoms and what combination of symptoms lead to a given disease are not well known. Even when the number of symptoms is small, the required number of experiments to generate adequate statistical data can be unmanageably large. There is need in diagnosis for an integrative model that incorporates both statistical data and expert judgment. When statistical data are present but no expert judgment is available, one property of this model should be to reproduce results obtained through time honored procedures such as Bayes theorem. When expert judgment is also present, it should be possible to combine judgment with statistical data to identify the disease that best describes the observed symptoms. Here we are interested in the Analytic Hierarchy Process (AHP) framework that deals with dependence among the elements or clusters of a decision structure to combine statistical and judgmental information. It is shown that the posterior probabilities derived from Bayes theorem are part of this framework, and hence that Bayes theorem is a sufficient condition of a solution in the sense of the AHP. An illustration is given as to how a purely judgment-based model in the AHP can be used in medical diagnosis. The application of the model to a case study demonstrates that both statistics and judgment can be combined to provide diagnostic support to medical practitioner colleagues with whom we have interacted in doing this work.
Finite element approximation of a displacement formulation for time-domain elastoacoustic vibrations
Authors: A. Bermúdez, R. Rodríguez, D. Santamarina
Venue: Journal of Computational and Applied Mathematics (2003)

This paper deals with the numerical solution of a system of second-order in time partial differential equations modeling the vibrations of a coupling between an elastic solid and an inviscid compressible fluid. Both media are described in terms of their respective displacement fields. The problem is solved in the time domain by combining a Newmark's scheme for time discretization with a finite element method for space discretization. The latter combines standard Lagrangian elements in the solid with lowest-order Raviart-Thomas elements in the fluid. Stability is proved and numerical results showing the good behavior of the method are reported.
Centralized Bakery Reduces Distribution Costs Using Simulation
Authors: Sampath Rajagopalan, Medini R. Singh, Thomas E. Morton, Ephraim Martin,  IV
Venue: Interfaces (1998)

To improve the efficiency of product distribution for a centralized bakery, I first performed each person's tasks and discovered that constructing optimal minimum-distance routes would not significantly reduce costs but replacing the physical validation of new routes with a manual mathematical computation or simulation would. The trick was getting management to trust the simulation enough to use it.
A concept-first approach for an introductory computer science course
Authors: Linda P. DuHadway, Stephen W. Clyde, Mimi M. Recker, Donald H. Cooley
Venue: Journal of Computing Sciences in Colleges (2002)

Several weaknesses have been identified to the programming-first approach often used in introductory computer science courses. Despite these weaknesses, programming continues to be the central focus in CS1 for many institutions. This paper proposes a concept-first approach that can be integrated into existing programming-first curriculum.The approach is based on three principles: a) drawing from the students' everyday experiences to introduce new ideas and skills; b) allowing students time to acquire a foundation in these concepts before introducing a high-level programming language; and c) separating fundamental concepts from language syntax. A feasibility study for integrating this new approach in a CS1 class at USU is described.
Convergence rate of the best-r-point-average estimator for the maximizer of a nonparametric regression function
Authors: Zhidong Bai, Zehua Chen, Yaohua Wu
Venue: Journal of Multivariate Analysis (2003)

The best-r-point-average (BRPA) estimator of the maximizer of a regression function, proposed in Changchien (in: M.T. Chao, P.E. Cheng (Eds.), Proceedings of the 1990 Taipei Symposium in Statistics, June 28-30, 1990, pp. 63-78) has certain merits over the estimators derived through the estimation of the regression function. Some of the properties of the BRPA estimator have been studied in Chen et al. (J. Multivariate Anal. 57 (1996) 191) and Bai and Huang (Sankhya: Indian J. Statist. Ser. A. 61 (Pt. 2) (1999) 208-217). In this article, we further study the properties of the BRPA estimator and give its convergence rate under some quite general conditions. Simulation results are presented for the illustration of the convergence rate. Some comparisons with existing estimators such as the Müller estimator are provided.
Multidisciplinary teams to fulfill apprenticeship requirements in industry
Authors: Joan Peckham, Deborah Rosen
Venue: Journal of Computing Sciences in Colleges (2003)

At the University of Rhode Island (URI), we require all B.S. CS majors to take two consecutive semesters of SEA (software engineering apprenticeship) with industry, or with a research or development group on campus. The students are expected to find positions that require them to work with a group of software professionals to carry out software design, implementation, quality assurance and/or maintenance activities. Most students find individual positions in industry and are managed on site. In this funded project we managed two teams of 5 students from engineering, computer science, business administration, and art, with an MBA student from our Business program as manager. Students were also advised by a team of professionals from GTECH and professors at URI in a series of seminars to carry out the various aspects of their projects. The team composition mirrored the philosophy of removing specialized silos and creating teams at GTECH to carry out their own projects. In this project, the students were asked to spend some time on market analysis and software plans before the design and implementation phase. They designed and developed prototype video games for the company during two semesters. This was a highly popular project for the students. GTECH was also very happy with the results.
How to add a state-of-the-art component to your course
Authors: John A. Rupf
Venue: Journal of Computing Sciences in Colleges (2002)

The desire to learn the state of the art that students bring to a course can be enhanced and sustained during the "drudgery" of learning the basics by requiring the students to read and take quizzes on carefully selected articles from current professional journals. This technique was utilized in several courses and evaluations are presented relative to how well the technique met a series of five objectives.
Distributed policy-based management of measurement-based traffic engineering: design and implementation
Authors: S. Van den Berghe, P. Van Heuven, J. Coppens, F. De Turck, P. Demeester
Venue: Future Generation Computer Systems (2003)

This article discusses an architecture using monitoring feedback as an assisting factor for delivering QoS on packet-based networks. The handling of this feedback is done in an automated way, through the use of a policy-based management architecture. For this, a formal model for describing data plane and measurement objects was translated into an XML-based configuration language. On top of this, a proof-of-concept management architecture was developed and evaluated, using both a modified network simulator and enhanced Linux prototype routers.
Designing Portfolios of Financial Products Via Integrated Simulation and Optimization Models
Authors: Andrea Consiglio, Stavros A. Zenios
Venue: Operations Research (1999)

We analyze the problem of debt issuance through the sale of innovative financial products. The problem is broken down to questions of designing the financial products, specifying the debt structure with the amount issued in each product, and determining an optimal level of financial leverage. We formulate a hierarchical optimization model to integrate these three issues and provide constructive answers. Input data for the models are obtained from Monte Carlo simulation procedures that generate scenarios of holding period returns of the designed products. The hierarchical optimization model is specialized for the problem of issuing a portfolio of callable bonds to fund mortgage assets. The upper level optimization program is multimodal, and a tabu search procedure is developed for its solution. Empirical results illustrate the efficacy of the developed models in designing the appropriate structure of the callable bonds and making optimal allocations of equity and debt among the designed products. Computational results with the implementation of tabu search-on both serial and parallel computers-are also presented.
Production Planning with Flexible Product Specifications: An Application to Specialty Steel Manufacturing
Authors: Anantaram Balakrishnan, Joseph Geunes
Venue: Operations Research (2003)

Responding to varying customer needs for product customization, quantities, or lead times requires increased manufacturing flexibility. In certain contexts, the reverse is true, i.e., customer requirements are somewhat flexible, providing additional options in production planning. This paper considers such an opportunity faced by a specialty steel manufacturer whose customers allow flexibility in product specifications. We develop and test a model and solution methodology to exploit this flexibility during production planning. The model also applies to other situations in which manufacturers can select, within limits, the size or quantities of items produced using limited capacity. We formulate the problem as a profit-maximizing mixed-integer program with an interesting embedded packing subproblem using "expandable" items. We develop a composite solution method that combines model enhancement using strong valid inequalities, Lagrangian relaxation, and heuristic approaches. Computational results using real data from a specialty steel manufacturer and randomly generated test problems show that the algorithm generates solutions that are, on average, within 0.59% of optimality. For the problem instances based on real data, the model increases contribution to profit by over 7% relative to current practice at the steel manufacturing facility.
Robust Process Control at Cerestar'S Refineries
Authors: Kumar Rajaram, R. Jaikumar, Franz Behlau, Frans Van Esch, Corrie Heynen, Ralph Kaiser, Albert Kuttner, Izaak Van De Wege
Venue: Interfaces (1999)

With annual sales of over $2 billion, Cerestar is Europe's lead-ing manufacturer of made-to-order wheat- and corn-based starch products. Cerestar relies on refineries that are highly automated and require large fixed investments. Starting in 1993, we developed Robust Process Control (RPC) to increase average throughput and reduce throughput variation by combining engineering principles with OR/MS techniques. RPC includes a mathematical-programming model to reduce downtimes due to product switchovers, models for process optimization, and dynamic control models for process-flow synchronization. Cerestar implemented the resulting decision support system at eight refineries in six countries. It has increased average daily throughputs by 20 percent and reduced average throughput variation by 50 percent. Concomitantly, the refineries have reduced their consumption of supplies and utilities. In addition to over $11 million in annual benefits, RPC has had major strategic and organizational impact.
Segmentation of Multiple Salient Closed Contours from Real Images
Authors: Shyjan Mahamud, Lance R. Williams, Karvel K. Thornber, Kanglin Xu
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2003)

Using a saliency measure based on the global property of contour closure, we have developed a segmentation method which identifies smooth closed contours bounding objects of unknown shape in real images. The saliency measure incorporates the Gestalt principles of proximity and good continuity that previous methods have also exploited. Unlike previous methods, we incorporate contour closure by finding the eigenvector with the largest positive real eigenvalue of a transition matrix for a Markov process where edges from the image serve as states. Element(i,j)of the transition matrix is the conditional probability that a contour which contains edgejwill also contain edgei . In this paper, we show how the saliency measure, defined for individual edges, can be used to derive a saliency relation, defined for pairs of edges, and further show that strongly-connected components of the graph representing the saliency relation correspond to smooth closed contours in the image. Finally, we report for the first time, results on large real images for which segmentation takes an average of about10seconds per object on a general-purpose workstation.
An Approximate Analysis of a Unix Macro Process Scheduler
Authors: Robert A. Benhenni
Venue: INFORMS Journal on Computing (1998)

A UNIX macro process scheduler, referred to as the Fair Share Scheduler (FSS), is a UNIX scheduling algorithm that allocates different shares of the processor capacity to different groups of processes. First, the scheduling algorithm is approximated by a generalized processor-sharing discipline. Then, a second approximation is made to derive the mean response times of the different groups and the optimal allocation of shares among the groups. Finally, an application is shown where substantial performance improvements are observed.
Common Mistakes in Making Value Trade-Offs
Authors: Ralph L. Keeney
Venue: Operations Research (2002)

Value trade-offs define how much must be gained in the achievement of one objective to compensate for a lesser achievement on a different objective. Value trade-offs that adequately express a decision maker's values are essential both for good decision making in multiple-objective contexts and for insightful analyses of multiple-objective decisions. This paper identifies and illustrates 12 important mistakes frequently made that limit one's ability to determine useful value trade-offs. It then suggests how to avoid making these mistakes. The intent is to provide practical advice for making good value trade-offs, and hence, better decisions.
The Batch Loading and Scheduling Problem
Authors: Gregory Dobson, Ramakrishnan S. Nambimadom
Venue: Operations Research (2001)

This paper discusses the problem of batching and scheduling of certain kinds of batch processors. Examples of these processors include heat treatment facilities, particularly in the steel and ceramics industries, as well as a variety of operations in the manufacture of integrated circuits. In general, for our problem there is a set of jobs waiting to be processed. Each job is associated with a given family and has a weight or delay cost and a volume. The scheduler must organize jobs into batches in which each batch consists of jobs from a single family and in which the total volume of jobs in a batch does not exceed the capacity of the processor. The scheduler must then sequence all the batches. The processing time for a batch depends only on the family and not on the number or the volume of jobs in the batch. The objective is to minimize the mean weighted flow time.The paper presents an integer programming formulation for this problem, generates a lower bound from a partial LP relaxation, provides a polynomial algorithm to solve a special case, and tests a set of heuristics on the general problem. The ability to pack jobs into batches is the key to efficient solutions and is the basis of the different solution procedures in this paper. The heuristics include a greedy heuristic, a successive knapsack heuristic, and a generalized assignment heuristic. Optimal solutions are obtained by complete enumeration for small problems.The conclusions of the computational study show that the successive knapsack and generalized assignment heuristics perform better than the greedy. The generalized assignment heuristic does slightly better than the successive knapsack heuristic in some cases, but the latter is substantially faster and more robust. For problems with few jobs, the generalized assignment heuristic and the knapsack heuristic almost always provide optimal solutions. For problems with more jobs, we compare the heruistic solutions' values to lower bounds; the computational work suggests that the heuristics continue to provide solutions that are optimal or close to the optimal. The study also shows that the volume of the job relative to the capacity of the facility and the number of jobs in a family affect the performance of the heuristics, whereas the number of families does not. Finally, we give a worst-case analysis of the greedy heuristic.
Declarative specification of Web sites with S
Authors: Mary Fernández, Daniela Florescu, Alon Levy, Dan Suciu
Venue: The VLDB Journal &mdash; The International Journal on Very Large Data Bases (2000)

S is a system for implementing data-intensive Web sites, which typically integrate information from multiple data sources and have complex structure. S's key idea is separating the management of a Web site's data, the specification of its content and structure, and the visual representation of its pages. S provides a declarative query language for specifying a site's content and structure, and a simple template language for specifying a site's HTML representation. This paper contains a comprehensive description of the S system and details the benefits of declarative site specification. We describe our experiences using S in a production application and describe three different, but complementary, systems that extend and improve upon S's original ideas.
Trust-Based Facilitator: Handling Word-of-Mouth Trust for Agent-Based E-Commerce
Authors: Chihiro Ono, Satoshi Nishiyama, Keesoo Kim, Boyd C. Paulson, Mark Cutkosky, Charles J. Petrie
Venue: Electronic Commerce Research (2003)

This paper proposes a facilitator which finds capable and trustworthy partners on behalf of client users (agents), which helps agents form and maintain e-partnerships for electronic commerce. Unlike existing capability-based facilitators or matchmakers, the facilitator collects and maintains private &ldquo;word-of-mouth&rdquo; trust information as well as capabilities from each agent and uses the information for personalized trust-based facilitation for each agent, which is performed through the facilitation protocols and trust propagation mechanism. Compared to other existing trust mechanisms, the characteristics of trust which this facilitator handles are personalized-collaborative-subjective-qualitative-private. The facilitator is implemented as a JATLite multi-agent system and a FIPA-OS based multi-agent system, and is evaluated in terms of the complexity and characteristics. The example of usage is shown in the area of construction supply-chain coordination.
The Peoples Gas Light and Coke Company Plans Gas Supply
Authors: Thomas W. Knowles, John P. Wirick,  Jr.
Venue: Interfaces (1998)

A gas utility's profits depend on its portfolio of gas supply and storage contracts and their effective utilization. The Peoples Gas Light and Coke Company serves the Chicago market. Demand for natural gas depends on temperature, which is difficult to forecast. We developed an optimization model that considers multiple weather scenarios in determining a supply portfolio. We originally developed it to support filings of integrated least-cost supply plans with the Illinois Commerce Commission. With deregulation of the natural gas industry, the company has used the model to restructure supply portfolios, saving more than $50 million annually.