ppxscal/embedding_network huggingface dataset:
High performance computing meets experimental mathematics
Authors: David H. Bailey, David Broadhurst, Yozo Hida, Xiaoye S. Li, Brandon Thompson
Venue: Proceedings of the 2002 ACM/IEEE conference on Supercomputing (2002)

In this paper we describe some novel applications of high performance computing in a discipline now known as "experimental mathematics." The paper reviews some recent published work, and then presents some new results that have not yet appeared in the literature. A key technique inovlved in this research is the PSLQ integer relation algorithm (recently named one of ten "algorithms of the century" by Computing in Science and Engineering). This algorithm permits one to recognize a numeric constant in terms of the formula that it satisfies. We present a variant of PSLQ that is well-suited for parallel computation, and give several examples of new mathematical results that we have found using it. Two of these computations were performed on highly parallel computers, since they are not feasible on conventional systems. We also describe a new software package for performing arbitrary precision arithmetic, which is required in this research.
Media Access Protocols For A Scalable Optical Interconnection Network
Authors: Thomas S. Jones, Ahmed Louri
Venue: Proceedings of the 1998 International Conference on Parallel Processing (1998)

Hierarchical optical interconnection networks have the potential of solving the communication bottleneck that has evolved in parallel processing systems due the big increases in processor speeds. Hierarchical Optical Ring Interconnection Network (HORN) is one network architecture that was proposed to provide scalability to a larger number of processing nodes (PNs) with low latency and high bandwidth. In HORN PNs are arranged in rings and those rings are grouped together hierarchically in higher level rings. While collisions of data from multiple sources in hierarchical networks like HORN are reduced by separating nodes spatially and by wavelength, they can't be prevented completely and media access control (MAC) protocols must be used to that end. An in-depth analysis of five collision-free, single hop protocols is perfromed in terms of average delay and system throughput. The protocols analyzed are: time division multiple access (TDMA), TDMA with arbitration, FatMAC, decoupled multichannel optical network (DMON), and token hierarchical optical ring network (THORN). The first four protocols are documented in the literature but the fifth, THORN, was developed expressly for HORN. While all the protocols support the scalability objectives of HORN, THORN is shown to have the lowest delay with a throughput comparable to the other four protocols.
Variables bounding based retiming algorithm
Authors: Zongwei Lu, Zhenghui Lin, Houpeng Chen
Venue: Journal of Computer Science and Technology (2002)

Retiming is a technique for optimizing sequential circuits. In this paper, we discuss this problem and propose an improved retiming algorithm based on variables bounding. Through the computation of the lower and upper bounds on variables, the algorithm can significantly reduce the number of constraints and speed up the execution of retiming. Furthermore, the elements of matrixes D and W are computed in a demand-driven way, which can reduce the capacity of memory. It is shown through the experimental results on ISCAS89 benchmarks that our algorithm is very effective for large-scale sequential circuits.
Fuzzy classification trees for data analysis
Authors: I-Jen Chiang, Jane Yung-jen Hsu
Venue: Fuzzy Sets and Systems (2002)

Overly generalized predictions are a serious problem in concept classification. In particular, the boundaries among classes are not always clearly defined. For example, there are usually uncertainties in diagnoses based on data from biochemical laboratory examinations. Such uncertainties make the prediction be more difficult than noise-free data. To avoid such problems, the idea of fuzzy classification is proposed. This paper presents the basic definition of fuzzy classification trees along with their construction algorithm. Fuzzy classification trees is a new model that integrates the fuzzy classifiers with decision trees, that can work well in classifying the data with noise. Instead of determining a single class for any given instance, fuzzy classification predicts the degree of possibility for every class.Some empirical results the dataset from UCI Repository are given for comparing FCT and C4.5. Generally speaking, FCT can obtain better results than C4.5.
Parity law for population dynamics of N-species with cyclic advantage competitions
Authors: Kazunori Sato, Naoto Yoshida, Norio Konno
Venue: Applied Mathematics and Computation (2002)

We study population dynamics on lattice space with N species (N= 3, 4, 5, and 6) with cyclic competitive advantage, having both a weaker species and a stronger one. The steady state with equal population densities is the globally stable fixed point. For the biased-rate cyclic advantage population, we can observe the different features of the steady states and their stabilities for even N and for odd N, and we call it as "parity law". We obtain the following results on the parity law: (i) for odd number N all the species can coexist following the biased rate and we have the counterintuition for the change of equilibrium densities; (ii) for even N all the species cannot always coexist and it coincides with our intuition. We also analyzed mean-field approximation. It is revealed that most of the results of Monte Carlo simulation can be understood by mean-field approximation dynamics. However, equilibrium densities cannot be always predicted by mean-field approximation because of the spatial fixation.
A visual modeling framework for distributed object computing
Authors: Gabriele Taentzer
Venue: Proceedings of the IFIP TC6/WG6.1 Fifth International Conference on Formal Methods for Open Object-Based Distributed Systems V (2002)

Distributed object computing is a computing paradigm that allows objects to be distributed over a heterogeneous network. Infrastructures help to develop distributed object applications by offering necessary services for distributed computing. Having a comprehensive infrastructure to hand, the development of complex distributed object systems is feasible in principle. Flexibly evolving architectures as well as highly dynamic distributed object structures are key requirements for nowadays distributed solutions. They can hardly be well designed on this level of programming, due to their complexity. A visual modeling framework is presented which offers a more abstract and intuitive approach to the relevant aspects of a distributed object system. In this framework, network and object structures as well as their evolution are visualized in a diagrammatic style, e.g. in UML notation. Semantically, this approach relies on graphs and their transformation, i.e. it has a precise background useful for further reasoning.
Introducing the 2.6 kernel
Authors: Robert Love
Venue: Linux Journal (2003)

From the scheduler to the device drivers, there's a lot to like and learn about the upcoming Linux 2.6.
Fuzzy multiresolution signal representation
Authors: Robert Patton Leland
Venue: Fuzzy Sets and Systems (2002)

We present a multiresolution signal representation technique which uses fuzzy rules. A fuzzy tree is used to connect different levels of resolution. We apply our representation to several random processes, and demonstrate some useful properties of our representation when applied to fractals.
Knowledge as a Contingency Variable: Do the Characteristics of Knowledge Predict Organization Structure?
Authors: Julian Birkinshaw, Robert Nobel, Jonas Ridderstråle
Venue: Organization Science (2002)

This paper examines the validity of knowledge as a contingency variable. Building on recent advances in thinking about the dimensions of knowledge assets (Winter 1987, Zander and Kogut 1995), we argue that such dimensions might have an important influence on organization structure. More specifically, we focus on two dimensions of knowledge--observability and system embeddedness--and their influence over the level of unit autonomy and interunit integration in an international network of R&D units. Statistical analysis of questionnaire responses from 110 R&D unit managers show strong association between the dimensions of knowledge and organization structure. It also indicates partial support for the "fit" hypothesis in contingency theory.The paper makes two important contributions to the knowledge management literature. First, we find support for the contingency logic, suggesting that effective organization design has to take into account the underlying characteristics of the firm's knowledge base. Second, we shed light on a relatively neglected dimension of knowledge that we callsystem embeddedness. This is the extent to which knowledge is a function of the social and physical system in which it exists. In the statistical analysis it emerges as a strong predictor of organization structure. Moreover, it also appears to be conceptually distinct from the tacit-articulate dimension that is normally emphasized. This allows us to speculate on four generic forms that a firm's knowledge might take, that we label integrated, isolated, opaque, and transparent. These are discussed using examples from the data.
Anisotropic mesh adaptation through hierarchical error estimators
Authors: Michel Fortin
Venue: Scientific computing and applications (2001)

A posteriori error estimation and its use in mesh adaptation procedures has become one of the principal axes of development in the numerical analysis of partial differential equations. This paper would like to give a new insight on an anisotropic mesh adaptation technique which is based on a hierarchical error estimate. A simplified version will use information from a higher order reinterpolations of the solution. Even if they lack a complete mathematical justification, experimental evidence clearly shows that these methods work very well and that they provide a way to drive anisotropic mesh adaptation. Such anisotropic capabilities have led to spectacular results in the simulation of compressible flows with shocks([13], [11]). We present here a short description of the methodology and its underlying principles.
On the Scalability of Dynamic Scheduling Scientific Applications with Adaptive Weighted Factoring
Authors: Ioana Banicescu, Vijay Velusamy, Johnny Devaprasad
Venue: Cluster Computing (2003)

In heterogeneous environments, dynamic scheduling algorithms are a powerful tool towards performance improvement of scientific applications via load balancing. However, these scheduling techniques employ heuristics that require prior knowledge about workload via profiling resulting in higher overhead as problem sizes and number of processors increase. In addition, load imbalance may appear only at run-time, making profiling work tedious and sometimes even obsolete. Recently, the integration of dynamic loop scheduling algorithms into a number of scientific applications has been proven effective. This paper reports on performance improvements obtained by integrating the Adaptive Weighted Factoring, a recently proposed dynamic loop scheduling technique that addresses these concerns, into two scientific applications: computational field simulation on unstructured grids, and N-Body simulations. Reported experimental results confirm the benefits of using this methodology, and emphasize its high potential for future integration into other scientific applications that exhibit substantial performance degradation due to load imbalance.
Preconditioning by Gram matrix approximation for diffusion-convection-reaction equations with discontinuous coefficients
Authors: Gh. Juncu, C. Popa
Venue: Mathematics and Computers in Simulation (2002)

This work analyses the preconditioning with Gram matrix approximation for the numerical solution of a linear convection-diffusion-reaction equation with discontinuous diffusion and reaction coefficients. The standard finite element method with piecewise linear test and trial functions on uniform meshes discretizes the equation. Three preconditioned conjugate gradient algorithms solve the discrete linear system: CGS, CGSTAB and GMRES. The preconditioning with Gram matrix approximation consists of replacing the solving of the equation with the preconditioner by two symmetric MG iterations. Numerical results are presented to assess the convergence behaviour of the preconditioning and to compare it with other preconditioners of multilevel type.
Brownian Approximations of Multiclass Open-Queueing Networks
Authors: Hong Chen, Xinyang Shen, David D. Yao
Venue: Operations Research (2002)

We study a multiclass open-queueing network with a set of single-server stations that operate under a combination of FIFO (first-in-first out) and priority service disciplines, and are subject to random breakdowns. Assuming that the primitive processes--in particular, external arrivals, service requirements, service capacities (up and down times), and the routing mechanism--follow two-moment approximations (based on functional central limit theorems), we develop a semi-martingale reflected Brownian motion (SRBM) approximation for the performance processes such as workload, queue lengths, and sojourn times. We illustrate through numerical examples in comparison against simulation that the SRBM approximation, while not always supported by a limit theorem, exhibits good accuracy in most cases. Through analyzing special networks, we also discuss the existence of the SRBM approximation in relation to the stability and the heavy traffic limits of the networks.
Heuristics for the black and white traveling salesman problem
Authors: Mélanie Bourgeois, Gilbert Laporte, Frédéric Semet
Venue: Computers and Operations Research (2003)

The black and white traveling salesman problem (BWTSP) is defined on a graph G whose vertex set is partitioned into black and white vertices. The aim is to design a shortest Hamiltonian tour on G subject to two constraints: both the number of white vertices as well as the length of the tour between two consecutive black vertices are bounded above. The BWTSP has applications in airline scheduling and in telecommunications. This article proposes and compares several heuristics for the BWTSP. Computational results are reported for instances involving up to 200 vertices.
An efficient static analysis algorithm to detect redundant memory operations
Authors: Keith D. Cooper, Li Xu
Venue: ACM SIGPLAN Notices (2003)

As memory system performance becomes an increasingly dominant factor in overall system performance, it is important to optimize programs for memory related operations. This paper concerns static analysis to detect redundant memory operations and enable other compiler transformations to remove such redundant operations.We present an extended global value numbering algorithm to detect redundant memory operations. The key of the new algorithm is a novel SSA-based representation for memory state which allows accurate reasoning about memory state. Using this representation, the algorithm can trace values through memory operations to detect equivalence in the same way that it traces them through register-based scalar operations. Thus it discovers both redundancy involving scalar values and redundancy involving memory operations. The redundancy relation detected by the algorithm can then be used by traditional redundancy elimination transformations to remove those redundant operations.Experiments using a suite of realistic applications demonstrate the algorithm is powerful and fast. In practice, it has essentially linear time complexity.
On Heterogeneous Database Retrieval: A Cognitively Guided Approach
Authors: Ramayya Krishnan, Xiaoping Li, David Steier, Leon Zhao
Venue: Information Systems Research (2001)

Retrieving information from heterogeneous database systems involves a complex process and remains a challenging research area. We propose a cognitively guided approach for developing an information-retrieval agent that takes the user's information request, identifies relevant information sources, and generates a multidatabase access plan. Our work is distinctive in that the agent design is based on an empirical study of how human experts retrieve information from multiple, heterogeneous database systems. To improve on empirically observed information-retrieval capabilities, the design incorporates mathematical models and algorithmic components. These components optimize the set of information sources that need to be considered to respond to a user query and are used to develop efficient multidatabase-access plans. This agent design, which integrates cognitive and mathematical models, has been implemented using Soar, a knowledge-based architecture.
Vertical optical directional coupler: modeling, fabrication and test
Authors: H. Azarinia, B. Rashidian
Venue: Iranian Journal of Science and Technology (2002)

A method for fabricating optical directional couplers by combining thermal and field assisted ion exchange processes is presented. Modeling, design, fabrication, and test methods are discussed. This method eliminates the need for high-resolution lithography that is needed in conventional methods of coupler fabrication.
Automatic thesaurus generation for Chinese documents
Authors: Yuen-Hsien Tseng
Venue: Journal of the American Society for Information Science and Technology (2002)

This article reports an approach to automatic thesaurus construction for Chinese documents. An effective Chinese keyword extraction algorithm is first presented. Experiments showed that for each document an average of 33% keywords unknown to a lexicon of 123,226 terms could be identified by this algorithm. Of these unregistered words, only 8.3% of them are illegal. Keywords extracted from each document are further filtered for term association analysis. Association weights larger than a threshold are then accumulated over all the documents to yield the final term pair similarities. Compared to previous studies, this method speeds up the thesaurus generation process drastically, It also achieves a similar percentage level of term relatedness.
Generating Lyndon brackets: an addendum to: Fast algorithms to generate necklaces, unlabeled necklaces and irreducible polynomials over GF(2)
Authors: J. Sawada, F. Ruskey
Venue: Journal of Algorithms (2003)

It is well known that the Lyndon words of length n can be used to construct a basis for the nth homogeneous component of the free Lie algebra. We develop an algorithm that uses a dynamic programming table to efficiently generate the standard bracketing for all Lyndon words of length n, thus constructing a basis for the nth homogeneous component of the free Lie algebra. The algorithm runs in linear amortized time; i.e., O(n) time per basis element. For a single Lyndon word, the table (and thus the standard bracketing) can be computed in time O(n2).
Recognizing design patterns in C++ programs with integration of Columbus and Maisa
Authors: Rudolf Ferenc, Juha Gustafsson, László Müller, Jukka Paakki
Venue: Acta Cybernetica (2002)

A method for recognizing design patterns from C++ programs is presented. The method consists of two separate phases, analysis and reverse engineering of the C++ code, and architectural pattern matching over the reverse-engineered intermediate code representation. It is shown how the pattern recognition effect can be realized by integrating two specialized software tools, the reverse engineering framework Columbus and the architectural metrics analyzer Maisa. The method and the integrated power of the tool set are illustrated with small experiments.
Managing the Seed-Corn Supply Chain at Syngenta
Authors: Philip C. Jones, Greg Kegler, Timothy J. Lowe, Rodney D. Traub
Venue: Interfaces (2003)

Each year, Syngenta Seeds, Inc. produces over 50 seed-corn hybrids and the following year markets over 100 hybrids under the NK brand name. The fact that growing seed corn is a biological process dependent upon local weather and insect conditions during the growing season complicates production planning. In addition, customers' experiences with a particular hybrid during a given year strongly influence demand for that hybrid during the next year. To help mitigate some of these yield and demand uncertainties, Syngenta (and other seed companies as well) take advantage of a second growing season for seed corn in South America, which occurs after many of the yield uncertainties and some of the demand uncertainties have been resolved or reduced. To better manage this production-planning process, Syngenta and the University of Iowa developed and implemented a second-chance production-planning model. A trial of the model showed that using it to plan 2000 production would have increased margins by approximately $5 million. Today, Syngenta uses this model to plan production for those varieties that account for 80 percent of total sales volume.
Dispatching Buses in Parking Depots
Authors: Giorgio Gallo, Federico Di Miele
Venue: Transportation Science (2001)

Very often, space is a scarce resource in bus depots located in congested urban areas: Vehicles arriving at the end of their trips are packed together in a rather small space. This implies that when a vehicle has to leave to start a new trip, most often other vehicles have to be moved to clear the way. Here a new model, based on "Noncrossing Matching" and "Generalized Assignment," is presented to allocate parking spaces to vehicles in a depot to minimize the shunting cost. The results obtained by applying this approach to a real-life case are discussed.
Return on Quality at Chase Manhattan Bank
Authors: Roland T. Rust, Timothy Keiningham, Stephen Clemens, Anthony Zahorik
Venue: Interfaces (1999)

A method called "return on quality (ROQ)" has been proposedto evaluate the financial impact of efforts to improve service quality. It quantifies the projected net present value of an improvement project and calculates return on investment. During 1995 and 1996, Chase Manhattan Bank applied the method in a controlled experiment with four test branches and four control branches within the retail banking network, with a two-day training program aimed at enhancing service delivery and customer satisfaction. Its primary purpose was to assess the use-fulness of the ROQ approach in improving customer service. Largely because of the bank's merger with Chemical Bank, the study was not executed as planned. Despite this, the study showed favorable results from the training effort. The ROQ model facilitated interpretation of the study and appears useful for estimating the financial returns arising from service quality initiatives.
Local correspondence for detecting random forgeries
Authors: Jinhong Katherine Guo, David S. Doermann, Azriel Rosenfeld
Venue: Proceedings of the 4th International Conference on Document Analysis and Recognition (1997)

Progress on the problem of signature verification has advanced more rapidly in online applications than offline applications, in part because information which can easily be recorded in online environments, such as pen position and velocity, is lost in static offline data. In offline applications, valuable information which can be used to discriminate between genuine and forged signatures is embedded at the stroke level. We present an approach to segmenting strokes into stylistically meaningful segments and establish a local correspondence between a questioned signature and a reference signature to enable the analysis and comparison of stroke features. Questioned signatures which do not conform to the reference signature are identified as random forgeries. Most simple forgeries can also be identified, as they do not conform to the reference signature's invariant properties such as connections between letters. Since we have access to both local and global information, our approach also shows promise for extension to the identification of skilled forgeries.