ppxscal/embedding_network huggingface dataset:
An inverse problem for the three-dimensional multi-connected vibrating membrane with Robin boundary conditions
Authors: E. M. E. Zayed
Venue: Applied Mathematics and Computation (2002)

This paper deals with the very interesting problem about the influence of the boundary conditions on the distribution of the eigenvalues of the negative Laplacian in R3. The trace of the heat semigroup θ(t) = Σv=1∞ exp(-tµv), where {µv}v=1∞, are the eigenvalues of the negative Laplacian -∇2 = - Σβ=13 (∂/∂xβ)2 in the (x1,x2,x3)-space, is studied for a general multiply connected bounded domain Ω in R3 surrounded by simply connected bounded domains Ωj with smooth bounding surfaces Sj (j = 1,...,n), where a finite number of piecewise smooth Robin boundary conditions on the piecewise smooth components Si* (i = 1 + kj-1,...,kj) of the bounding surfaces Sj are considered, such that Sj = ∪i=1+kj-1kj Si*, where k0 = 0. Some applications of θ(t) for an ideal gas enclosed in the multiply connected bounded container Ω with Robin boundary conditions are given. We show that the asymptotic expansion of θ(t) for short-time t plays an important role in investigating the influence of the finite container Ω on the thermodynamic quantities of an ideal gas.
An Algorithm for Identifying the Frame of a Pointed Finite Conical Hull
Authors: J. H. Dula, R.V. Helgason, N. Venugopal
Venue: INFORMS Journal on Computing (1998)

We present an algorithm for identifying the extreme rays of the conical hull of a finite set of vectors whose generated cone is pointed. This problem appears in diverse areas including sto-chastic programming, computational geometry, and non-parametric efficiency measurement. The standard approach consists of solving a linear program for every element of the set of vectors. The new algorithm differs in that it solves fewer and substantially smaller LPs. Extensive computational testing vali-dates the algorithm and demonstrates that for a wide range of problems it is computationally superior to the standard approach.
Computing small partial coverings
Authors: Markus Bläser
Venue: Information Processing Letters (2003)

We study the generalization of covering problems such as the set cover problem to partial covering problems. Here we only want to cover a given number k of elements rather than all elements. For instance, in the k-partial (weighted) set cover problem, we wish to compute a minimum weight collection of sets that covers at least k elements. As a main result, we show that the k-partial set cover problem and its special cases like the k-partial vertex cover problem are all fixed parameter tractable (with parameter k). As a second example, we consider the minimum weight k-partial t-restricted cycle cover problem.
Change impact analysis to support architectural evolution
Authors: Jianjun Zhao, Hongji Yang, Liming Xiang, Baowen Xu
Venue: Journal of Software Maintenance: Research and Practice (2002)

Change impact analysis is a useful technique in software maintenance and evolution. Many techniques have been proposed to support change impact analysis at the code level of software systems, but little effort has been made for change impact analysis at the architectural level. In this paper, we present an approach to supporting change impact analysis at the architectural level of software systems based on an architectural slicing and chopping technique. The main feature of our approach is to assess the effect of changes in a software architecture by analyzing its formal architectural specification, and, therefore, the process of change impact analysis can be automated completely. John Wiley & Sons, Ltd.
1 V All-MOS &Sigma;&Delta; A/D Converters in the Log-domain
Authors: Francisco Serra-Graells
Venue: Analog Integrated Circuits and Signal Processing (2003)

This paper presents novel low-voltage all-MOS analog circuit techniques for the synthesis of oversampling &Sigma;&Delta; A/D converters. The new approach exploits the possibilities of Log-domain processing by using the MOSFET in subthreshold operation. Based on this strategy, a complete set of very low-voltage (down to 1 V) low-power (below 100 &mu;W) all-MOS basic building blocks is proposed. The resulting analog circuit techniques allow the integration of &Sigma;&Delta; A/D converters for low-frequency (below 100 KHz) applications in digital CMOS technologies. Examples are given for a standard 0.35 &mu;m VLSI process.
The Analytic Hierarchy Process--An Exposition
Authors: Ernest H. Forman., Saul I. Gass
Venue: Operations Research (2001)

This exposition on the Analytic Hierarchy Process (AHP) has the following objectives: (1) to discuss why AHP is a general methodology for a wide variety of decision and other applications, (2) to present brief descriptions of successful applications of the AHP, and (3) to elaborate on academic discourses relevant to the efficacy and applicability of the AHP vis-a-vis competing methodologies. We discuss the three primary functions of the AHP: structuring complexity, measurement on a ratio scale, and synthesis, as well as the principles and axioms underlying these functions. Two detailed applications are presented in a linked document athttp://mdm.gwu.edu/FormanGass.pdf.
Adapting to Radical Change: Strategy and Environment in Piece-Rate Adoption During China's Transition
Authors: Lisa A. Keister
Venue: Organization Science (2002)

Adaptation to radical change is central to research in organization theory, and some of the most dramatic examples of environmental change have occurred recently in transition economies such as China. I take advantage of change during China's economic reform to study the relative importance of organizational and environmental factors in producing innovative managerial response. I find that strategic choice predicted innovation in the early stages of reform, but environmental factors increased in salience over time. Intrafirm support, Communist Party connections, and a market orientation produced innovation early in reform. Simple imitation of others was also salient in early years. As reform progressed, managers increasingly imitated other profitable firms and drew on their own experience. My results inform an understanding of both the process by which innovation occurs and firm behavior in transition economies.
Parallel Scheduling of Multiclass M/M/m Queues: Approximate and Heavy-Traffic Optimization of Achievable Performance
Authors: Kevin D. Glazebrook, José Niño-Mora
Venue: Operations Research (2001)

We address the problem of scheduling a multiclassM/M/m queue with Bernoulli feedback onm parallel servers to minimize time-average linear holding costs. We analyze the performance of a heuristic priority-index rule, which extends Klimov's optimal solution to the single-server case: servers select preemptively customers with larger Klimov indices. We present closed-form suboptimality bounds ( approximate optimality) for Klimov's rule, which imply that its suboptimality gap is uniformly bounded above with respect to (i) external arrival rates, as long as they stay within system capacity; and (ii) the number of servers. It follows that itsrelative suboptimality gap vanishes in a heavy-traffic limit, as external arrival rates approach system capacity ( heavy-traffic optimality). We obtain simpler expressions for the special no-feedback case, where the heuristic reduces to the classical cÂµ rule. Our analysis is based on comparing the expected cost of Klimov's rule to the value of a strong linear programming (LP) relaxation of the system's region of achievable performance of mean queue lengths. In order to obtain this relaxation, we derive and exploit a new set ofwork decomposition laws for the parallel-server system. We further report on the results of a computational study on the quality of the cÂµ rule for parallel scheduling.
3D numerical simulation of drop coalescence
Authors: Ivan B. Bazhlekov Frans N. van de Vosse Han E. H. Meijer
Venue: Scientific computing and applications (2001)

The major importance of drop coalescence in a number of natural and industrial processes provides the motivation for fundamental experimental and theoretical studies on its mechanics. One of the main difficulties of such investigations is related with the presence of a thin liquid film, typically of order 10-4 of the drop size. In numerical studies of coalescence this requires very fine spatial diseretization which, combined with the numerical instabilities typical for multiphase flows may lead to enormous CPU time.In the present study, a boundary integral method for numerical simulation of 3D drop-to-drop interactions is considered in the case of Newtonian liquids and negligible inertial forces. The main attention is directed to the application of a multiple time step approach, which can reduce the computational time required with some orders of magnitude without influencing the accuracy of the solution. However, even with this improvement, the computational process is still far from useful in a more intensive investigation, especially for small capillary numbers, which is practically the most interesting case. A modification of the existing numerical methods for 2D film drainage and rupture, taken into account a 3D-based interaction force, proves to be a successful alternative to the simulations of 3D drop coalescence.
Stability of discretizations of the Stokes problem on anisotropic meshes
Authors: Thomas Apel, H. Maharavo Randrianarivony
Venue: Mathematics and Computers in Simulation (2003)

Anisotropic features of the solution of flow problems are usually approximated on anisotropic (large aspect ratio) meshes. This paper reviews stability results of several velocity-pressure pairs with respect to growing aspect ratio of the elements in the mesh. For further pairs numerical tests are described. Related results are mentioned.
On reducibility and symmetry of disjoint NP pairs
Authors: Pavel Pudlák
Venue: Theoretical Computer Science (2003)

We consider some problems about pairs of disjoint NP sets. The theory of these sets with a natural concept of reducibility is, on the one hand, closely related to the theory of proof systems for propositional calculus, and, on the other, it resembles the theory of NP completeness. Furthermore, such pairs are important in cryptography. Among others, we prove that the Broken Mosquito Screen pair of disjoint NP sets can be polynomially reduced to Clique-Coloring pair and thus is polynomially separable and we show that the pair of disjoint NP sets canonically associated with the Resolution proof system is symmetric.
On a problem in quantum summation
Authors: Stefan Heinrich, Erich Novak
Venue: Journal of Complexity (2003)

We consider the computation of the mean of sequences in the quantum model of computation. We determine the query complexity in the case of sequences which satisfy a p- summability condition for 1 ≤ p > 2. This settles a problem left open in Heinrich (J. Complexity 18 (2002) 1).
Algorithm visualization in CS education: comparing levels of student engagement
Authors: Scott Grissom, Myles F. McNally, Tom Naps
Venue: Proceedings of the 2003 ACM symposium on Software visualization (2003)

Software technology for algorithm visualization (AV) has advanced faster than our understanding of how such technology impacts student learning. In this paper we present results of a multi-university study. We measured the effect of varying levels of student engagement with AV to learn simple sorting algorithms. These levels included: 1) not seeing any visualization, 2) simply viewing visualizations for a short period in the classroom, and 3) interacting directly with the visualizations for an extended period outside of the classroom. Our results show that learning increases as the level of student engagement increases. AV has a bigger impact on learning when students go beyond merely viewing a visualization and are required to engage in additional activities structured around the visualization. In particular, students who responded to questions integrated into the AV tool during their exploration of an algorithm showed the most improvement between a pretest and posttest.
Post-graduate assessment of CS students: experience and position paper
Authors: Hisham Haddad
Venue: Journal of Computing Sciences in Colleges (2002)

This paper describes first-hand experience with post-graduate skill assessment of newly hired CS students at a small software development company. The assessment included technical and cognitive skills. The paper focuses on the cognitive skills (mainly critical thinking and problem solving), and it represents the author's position on the re-enforcing critical thinking and problem solving throughout the CS curriculum. The experience described in this paper does not represent a formal study of student skill assessment. The group of students involved in the assessment task represents a very small sample, and the outcomes do not represent the general population of CS students. The paper highlights most noticed deficiencies and recommends remedies that can help students overcome such problems.
The Mover-Stayer Model for the Hiv/Aids Epidemic in Action
Authors: Carla Rossi, Giuseppe Schinaia
Venue: Interfaces (1998)

Short- and medium-term projections of the HIV/AIDS epidemic indicators are of great interest to those evaluating the needs for health care and prevention interventions. We developed a simulation procedure to obtain forecasts of the HIV/AIDS epidemic and used it to estimate the characteristic regional parameters of the epidemic in Italy. The simulation procedure is based on a hybrid compartmental model, in which the epidemic evolves via nonrandom mixing patterns. Because of its structure, the model is suitable for policy making; in particular, for evaluating prevention campaigns, alternate forms of health care for people with AIDS, and drug supply needs. The model will also be used to estimate the number of intravenous drug users in Italy and the number of AIDS cases not reported or reported with a delay to the Italian surveillance system.
A Parallel, Linear Programming-based Heuristic for Large-Scale Set Partitioning Problems
Authors: Jeff T. Linderoth, Eva K. Lee, Martin W. P. Savelsbergh
Venue: INFORMS Journal on Computing (2001)

We describe a parallel, linear programming and implication-based heuristic for solving set partitioning problems on distributed memory computer architectures. Our implementation is carefully designed to exploit parallelism to greatest advantage in advanced techniques like preprocessing and probing, primal heuristics, and cut generation. A primaldual subproblem simplex method is used for solving the linear programming relaxation, which breaks the linear programming solution process into natural phases from which we can exploit information to find good solutions on the various processors. Implications from the probing operation are shared among the processors. Combining these techniques allows us to obtain solutions to large and difficult problems in a reasonable amount of computing time.
Culture issues and mobile UI design
Authors: Emilie W. Gould, Pia Honold, Masaaki Kurosu, Jay Melican, Aaron Marcus, Li Anne Yu
Venue: CHI '03 extended abstracts on Human factors in computing systems (2003)

Culture anthropologists have identified fundamental dimensions of world cultures. UIs designers have identified basic components of UIs. Mobile devices must map these dimensions to components to cope with global product and service development. Ultimately, tools may emerge to facilitate tuning designs per culture.
Target-Oriented Branch and Bound Method for Global Optimization
Authors: Volker Stix
Venue: Journal of Global Optimization (2003)

We introduce a very simple but efficient idea for branch and bound ({\cal B} {\cal B}) algorithms in global optimization (GO). As input for our generic algorithm, we need an upper bound algorithm for the GO maximization problem and a branching rule. The latter reduces the problem into several smaller subproblems of the same type. The new {{\cal B} {\cal B} approach delivers one global optimizer or, if stopped before finished, improved upper and lower bounds for the problem. Its main difference to commonly used {{\cal B} {\cal B} techniques is its ability to approximate the problem from above and from below while traversing the problem tree. It needs no supplementary information about the system optimized and does not consume more time than classical {{\cal B} {\cal B} techniques. Experimental results with the maximum clique problem illustrate the benefit of this new method.
Localization of function in neurocontrollers
Authors: Lior Segev, Ranit Aharonov, Isaac Meilijson, Eytan Ruppin
Venue: Proceedings of the seventh international conference on simulation of adaptive behavior on From animals to animats (2002)

This paper presents the Functional Contribution Algorithm (FCA) that addresses the fundamental challenge of localizing functions in artificial and natural neural networks. The FCA is based on an assignment of contribution values to the elements of the network, such that the ability to predict the network's performance in response to multi-lesions is maximized. The algorithm is thoroughly examined on evolved neurocontrollers, which are simple enough, but not too simple. We demonstrate that the FCA portrays a stable set of contributions and accurate multi-lesion predictions, which are significantly better than those obtained based on the classical single-lesion approach. Our results demonstrate the potential of the FCA to provide insights into the organization of both animat and animate nervous systems.
Composite Variable Formulations for Express Shipment Service Network Design
Authors: Andrew P. Armacost, Cynthia Barnhart, Keith A. Ware
Venue: Transportation Science (2002)

In this paper we describe a new approach to solving the express shipment service network design problem. Conventional polyhedral methods for network design and network loading problems do not consistently solve instances of the planning problem we consider. Under a restricted version of the problem, we transform conventional formulations to a new formulation using what we termcomposite variables. By removing flow decisions as explicit decisions, this extended formulation is cast purely in terms of the design elements. We establish that its linear programming relaxation gives stronger lower bounds than conventional approaches. We apply this composite variable formulation approach to the UPS Next Day Air delivery network and demonstrate potential annual cost savings in the hundreds of millions of dollars.
Conditioning on One-Step Survival for Barrier Option Simulations
Authors: Paul Glasserman, Jeremy Staum
Venue: Operations Research (2001)

Pricing financial options often requires Monte Carlo methods. One particular case is that of barrier options, whose payoff may be zero depending on whether or not an underlying asset crosses a barrier during the life of the option. This paper develops variance reduction techniques that take advantage of the special structure of barrier options, and are appropriate for general simulation problems with similar structure. We use a change of measure at each step of the simulation to reduce the variance arising from the possibility of a barrier crossing at each monitoring date. The paper details the theoretical underpinnings of this method, and evaluates alternative implementations when exact distributions conditional on one-step survival are available and when not available. When these one-step conditional distributions are unavailable, we introduce algorithms that combine change of measure and estimation of conditional probabilities simultaneously. The methods proposed are more generally applicable to terminal reward problems on Markov processes with absorbing states.
Echelon Reorder Points, Installation Reorder Points, and the Value of Centralized Demand Information
Authors: Martin I. Reiman, Lawrence M. Wein, Fangruo Chen
Venue: Management Science (1998)

We consider a serial inventory system with N stages. The material flows from an outside supplier to stage N, then to stage N - 1, etc., and finally to stage 1 where random customer demand arises. Each stage replenishes a stage-specific inventory position according to a stage-specific reorder point/order quantity policy. Two variations of this policy are considered. One is based on echelon stock, and the other installation stock. The former requires centralized demand information, while the latter does not. The relative cost difference between the two policies is called the value of centralized demand information. For fixed order quantities, we develop efficient algorithms for computing both the optimal echelon reorder points and the optimal installation reorder points. These algorithms enable us to conduct an extensive computational study to assess the value of centralized demand information and to understand how this value depends on several key system parameters, i.e., the number of stages, lead times, batch sizes, demand variability, and the desired level of customer service.
A hierarchical fuzzy-genetic multi-agent architecture for intelligent buildings online learning, adaptation and control
Authors: Hani Hagras, Victor Callaghan, Martin Colley, Graham Clarke
Venue: Information Sciences&mdash;Informatics and Computer Science: An International Journal (2003)

In this paper, we describe a new application domain for intelligent autonomous systems--intelligent buildings (IB). In doing so we present a novel approach to the implementation of IB agents based on a hierarchical fuzzy genetic multi-embedded-agent architecture comprising a low-level behaviour based reactive layer whose outputs are co-ordinated in a fuzzy way according to deliberative plans. The fuzzy rules related to the room resident comfort are learnt and adapted online using our patented fuzzy-genetic techniques (British patent 99-10539.7). The learnt rule base is updated and adapted via an iterative machine-user dialogue. This learning starts from the best stored rule set in the agent memory (Experience Bank) thereby decreasing the learning time and creating an intelligent agent with memory. We discuss the role of learning in building control systems, and we explain the importance of acquiring information from sensors, rather than relying on pre-programmed models, to determine user needs. We describe how our architecture, consisting of distributed embedded agents, utilises sensory information to learn to perform tasks related to user comfort, energy conservation, and safety. We show how these agents, employing a behaviour-based approach derived from robotics research, are able to continuously learn and adapt to individuals within a building, whilst always providing a fast, safe response to any situation. In addition we show that our system learns similar rules to other offline supervised methods but that our system has the additional capability to rapidly learn and optimise the learnt rule base. Applications of this system include personal support (e.g. increasing independence and quality of life for older people), energy efficiency in commercial buildings or living-area control systems for space vehicles and planetary habitation modules.