bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-scale geochemical mapping in China
Authors: Xie Xuejing , Wang Xueqiu , Zhang Qin , Zhou Guohua , Cheng Hangxin , Liu Dawen , Cheng Zhizhong , Xu Shanfa
Published: July 2008

Regional-, national- and global-scale geochemical mapping projects have been carried out in China since the late 1970s. These geochemical mapping projects have provided high-quality data for both mineral resource investigations and environmental assessments. Four national-scale geochemical mapping projects in China are described here. (1) The Regional Geochemistry–National Reconnaissance (RGNR) project is China's largest national-scale geochemical mapping project and has covered more than 6 million km
2
of the country's hilly and mountainous regions since 1978. Generally, stream-sediment samples were collected at a density of 1 sample per km
2
and four samples were composited into one analytical sample for analysis of 39 elements. (2) The Deep-penetrating Geochemical Mapping (DEEPMAP) project has been conducted in covered terrains, including basins, at a density of 1 sample per 100 km
2
with analysis of 30–70 elements since 1994. In the past ten years, an area of approximately 800 000 km
2
has been covered. (3) The 76 Geochemical Element Mapping (76 GEM) project has been carried out since 1999. Approximately 1 million km
2
has been completed at present. (4) Multi-purpose eco-geochemical mapping projects have been conducted in the Quaternary plains of eastern China to provide data for environmental regulation and for improvement of agricultural practices since 1999. The data generated continue to play an important role in finding mineralization targets and ore deposits. China is also playing a leadership role in international geochemical mapping projects by transferring its expertise in sampling, chemical analysis and map generation to the developing countries through bilateral and multilateral collaboration. China is a leader in two large projects on a global scale: (1) the Environmental Geochemical Monitoring Network (EGMON) Project aims not only to have a quick overview of the geochemistry in China, but also to provide a pilot study for choosing the optimum sampling medium for geochemical mapping projects at a global scale; (2) the Geochemical Mapping Project uses delta and floodplain sediments of large rivers at a global scale.
Multiprocessor systems synthesis for multiple use-cases of multiple applications on FPGA
Authors: Kumar Akash , Fernando Shakith , Ha Yajun , Mesman Bart , Corporaal Henk
Published: July 2008

Future applications for embedded systems demand chip multiprocessor designs to meet real-time deadlines. The large number of applications in these systems generates an exponential number of use-cases. The key design automation challenges are designing systems for these use-cases and fast exploration of software and hardware implementation alternatives with accurate performance evaluation of these use-cases. These challenges cannot be overcome by current design methodologies which are semiautomated, time consuming, and error prone.

In this article, we present a design methodology to generate multiprocessor systems in a systematic and fully automated way for
multiple use-cases
. Techniques are presented to merge multiple use-cases into one hardware design to minimize cost and design time, making it well suited for fast design-space exploration (DSE) in MPSoC systems. Heuristics to partition use-cases are also presented such that each partition can fit in an FPGA, and all use-cases can be catered for.

The proposed methodology is implemented into a tool for Xilinx FPGAs for evaluation. The tool is also made available online for the benefit of the research community and is used to carry out a DSE case study with multiple use-cases of real-life applications: H263 and JPEG decoders. The generation of the entire design takes about 100 ms, and the whole DSE was completed in 45 minutes, including FPGA mapping and synthesis. The heuristics used for use-case partitioning reduce the design-exploration time elevenfold in a case study with mobile-phone applications.
Specification-driven directed test generation for validation of pipelined processors
Authors: Mishra Prabhat , Dutt Nikil
Published: July 2008

Functional validation is a major bottleneck in pipelined processor design due to the combined effects of increasing design complexity and lack of efficient techniques for directed test generation. Directed test vectors can reduce overall validation effort, since shorter tests can obtain the same coverage goal compared to the random tests. This article presents a specification-driven directed test generation methodology. The proposed methodology makes three important contributions. First, a general graph model is developed that can capture the structure and behavior (instruction set) of a wide variety of pipelined processors. The graph model is generated from the processor specification. Next, we propose a functional fault model that is used to define the functional coverage for pipelined architectures. Finally, we propose two complementary test generation techniques: test generation using model checking, and test generation using template-based procedures. These test generation techniques accept the graph model of the architecture as input and generate test programs to detect all the faults in the functional fault model. Our experimental results on two pipelined processor models demonstrate several orders-of-magnitude reduction in overall validation effort by drastically reducing both test-generation time and number of test programs required to achieve a coverage goal.
An energy characterization platform for memory devices and energy-aware data compression for multilevel-cell flash memory
Authors: Joo Yongsoo , Cho Youngjin , Shin Donghwa , Park Jaehyun , Chang Naehyuck
Published: July 2008

Memory devices often consume more energy than microprocessors in current portable embedded systems, but their energy consumption changes significantly with the type of transaction, data values, and access timing, as well as depending on the total number of transactions. These variabilities mean that an innovative tool and framework are required to characterize modern memory devices running in embedded system architectures.

We introduce an energy measurement and characterization platform for memory devices, and demonstrate an application to multilevel-cell (MLC) flash memories, in which we discover significant value-dependent programming energy variations. We introduce an energy-aware data compression method that minimizes the flash programming energy, rather than the size of the compressed data, which is formulated as an entropy coding with unequal bit-pattern costs. Deploying a probabilistic approach, we derive energy-optimal bit-pattern probabilities and expected values of the bit-pattern costs which are applicable to the large amounts of compressed data typically found in multimedia applications. Then we develop an energy-optimal prefix coding that uses integer linear programming, and construct a prefix-code table. From a consideration of Pareto-optimal energy consumption, we can make tradeoffs between data size and programming energy, such as a 41% energy savings for a 52% area overhead.
Postplacement voltage assignment under performance constraints
Authors: Wu Huaizhi , Wong Martin D.F. , Gosti Wilsin
Published: July 2008

Multi-Vdd is an effective method to reduce both leakage and dynamic power. A key challenge in a multi-Vdd design is to control the complexity of the power-supply system and limit the demand for level shifters. This can be tackled by grouping cells of different supply voltages into a small number of voltage islands. Recently, an elegant algorithm was proposed for generating voltage islands that balance the power-versus-design-cost tradeoff under performance requirement, according to the placement proximity of the critical cells. One prerequisite of this algorithm is an initial voltage assignment at the standard-cell level that meets timing. In this article, we present a novel method to produce quality voltage assignment which not only meets timing but also forms good proximity of the critical cells to provide a smooth input to the aforementioned voltage island generation. Our algorithm is based on effective delay budgeting and efficient computation of physical proximity by Voronoi diagram. Our extensive experiments on real industrial designs show that our algorithm leads to 25%--75% improvement in the voltage island generation in terms of the number of voltage islands generated, with computation time only linear to design size.
Resource sharing among mutually exclusive sum-of-product blocks for area reduction
Authors: Das Sabyasachi , Khatri Sunil P.
Published: July 2008

In state-of-the-art digital designs, arithmetic blocks consume a major portion of the total area of the IC. The arithmetic sum-of-product (SOP) is the most widely used arithmetic block. Some of the examples of SOP are adder, subtractor, multiplier, multiply-accumulator (MAC), squarer, chain-of-adders, incrementor, decrementor, etc. In this article, we introduce a novel, area-efficient architecture to share different SOP blocks which are used in a mutually exclusive manner. We implement the core functions of the largest SOP only once and reuse different parts of the core subblocks for all other SOP operations with the help of multiplexers. This architecture can be used in the nontiming-critical paths of the design, to save significant amounts of area. Our experimental data shows that the proposed sharing-based architecture results in about 37% area savings compared to the results obtained from a commercially available best-in-class datapath synthesis tool. In addition, our proposed shared implementation consumes about 18% less power. These improvements were verified on placed-and-routed designs as well.
Partitioning parameterized 45-degree polygons with constraint programming
Authors: Tseng I-Lun , Postula Adam
Published: July 2008

An algorithm for partitioning parameterized 45-degree polygons into parameterized trapezoids is proposed in this article. The algorithm is based on the plane-sweep technique and can handle polygons with complicated constraints. The input to the algorithm consists of the contour of a parameterized polygon to be partitioned and a set of constraints for parameters of the contour. The algorithm uses horizontal cuts only and generates a number of nonoverlapping trapezoids whose union is the original parameterized polygon. Processing of constraints and coordinates that contain first-order multiple-variable polynomials has been made possible by incorporating the JaCoP constraint programming library. The proposed algorithm has been implemented in Java programming language and can be used as the basis to build the trapezoidal corner stitching data structure for parameterized VLSI layout masks.
Power-aware SoC test planning for effective utilization of port-scalable testers
Authors: Sehgal Anuja , Bahukudumbi Sudarshan , Chakrabarty Krishnendu
Published: July 2008

Many system-on-chip (SoC) integrated circuits contain embedded cores with different scan frequencies. To better meet the test requirements for such heterogeneous SoCs, leading tester companies have recently introduced port-scalable testers, which can simultaneously drive groups of channels at different data rates. However, the number of tester channels available for scan testing is limited; therefore, a higher shift frequency can increase the test time for a core if the resulting test access architecture reduces the bit-width used to access it. We present a scalable test planning technique that exploits port scalability of testers to reduce SoC test time. We compare the proposed heuristic optimization method to two baseline methods based on prior works that use a single scan data rate for all embedded cores. We also propose a power-aware test planning technique to effectively utilize port-scalable testers under constraints of test power consumption. Experimental results are presented for power-aware test scheduling to illustrate the impact of power constraints on overall test time.
Hybrid differentiation strategies for simulation and analysis of applications in C++
Authors: Bartlett Roscoe A. , Waanders Bart G. Van Bloemen , Berggren Martin
Published: July 2008

Computationally efficient and accurate derivatives are important to the success of many different types of numerical methods. Automatic differentation (AD) approaches compute truncation-free derivatives and can be efficient in many cases. Although present AD tools can provide a convenient implementation mechanism, the computational efficiency rarely compares to analytically derived versions that have been carefully implemented. The focus of this work is to combine the strength of these methods into a hybrid strategy that attempts to achieve an optimal balance of implementation and computational efficiency by selecting the appropriate components of the target algorithms for AD and analytical derivation. Although several AD approaches can be considered, our focus is on the use of template overloading forward AD tools in C++ applications. We demonstrate this hybrid strategy for a system of partial differential equations in gas dynamics. These methods apply however to other systems of differentiable equations, including DAEs and ODEs.
High-performance implementation of the level-3 BLAS
Authors: Goto Kazushige , Van De Geijn Robert
Published: July 2008

A simple but highly effective approach for transforming high-performance implementations on cache-based architectures of matrix-matrix multiplication into implementations of other commonly used matrix-matrix computations (the level-3 BLAS) is presented. Exceptional performance is demonstrated on various architectures.
Evaluating exact VARMA likelihood and its gradient when data are incomplete
Authors: Jonasson Kristjan , Ferrando Sebastian E.
Published: July 2008

A detailed description of an algorithm for the evaluation and differentiation of the likelihood function for VARMA processes in the general case of missing values is presented. The method is based on combining the Cholesky decomposition method for complete data VARMA evaluation and the Sherman-Morrison-Woodbury formula. Potential saving for pure VAR processes is discussed and formulae for the estimation of missing values and shocks are provided. A theorem on the determinant of a low rank update is proved. Matlab implementation of the algorithm is in a companion article.
Algorithm 878
Authors: Jonasson Kristjan
Published: July 2008

Matlab functions for the evaluation of the exact log-likelihood of VAR and VARMA time series models are presented (vector autoregressive moving average). The functions accept incomplete data, and calculate analytical gradients, which may be used in parameter estimation with numerical likelihood maximization. Allowance is made for possible savings when estimating seasonal, structured or distributed lag models. Also provided is a function for creating simulated VARMA time series that have an accurate distribution from term one (they are
spin-up
free). The functions are accompanied by a a simple example driver, a program demonstrating their use for real parameter fitting, as well as a test suite for verifying their correctness and aid further development. The article concludes with description of numerical results obtained with the algorithm.
Algorithm 879
Authors: Lee Che-Rung , Stewart G. W.
Published: July 2008

Eigentest is a package that produces real test matrices with known eigensystems. A test matrix, called an eigenmat, is generated in a factored form, in which the user can specify the eigenvalues and has some control over the condition of the eigenvalues and eigenvectors. An eigenmat
A
of order
n
requires only
O
(
n
) storage for its representation. Auxiliary programs permit the computation of (
A
−
sI
)
b
, (
A
−
sI
)
T
b
, (
A
−
sI
)
−1
b
, and (
A
−
sI
)
−T
b
in
O
(
n
) operations. A special routine computes specified eigenvectors of an eigenmat and the condition of its eigenvalue. Thus eigenmats are suitable for testing algorithms based on Krylov sequences, as well as others based on matrix-vector products. This article introduces the eigenmat and describes implementations in Fortran 77, Fortran 95, C, and Matlab.
Updating an LU Factorization with Pivoting
Authors: Quintana-Ortí Enrique S. , Van De Geijn Robert A.
Published: July 2008

We show how to compute an LU factorization of a matrix when the factors of a leading principle submatrix are already known. The approach incorporates pivoting akin to partial pivoting, a strategy we call
incremental pivoting
. An implementation using the Formal Linear Algebra Methods Environment (FLAME) application programming interface (API) is described. Experimental results demonstrate practical numerical stability and high performance on an Intel Itanium2 processor-based server.
A new beginning, a fond farewell
Authors: Feldman Stuart I.
Published: July 2008

I am writing this column in my last month as President of ACM. It's been a great opportunity to support the Association's many successful programs and to expand and firmly establish new directions. Much has been accomplished, much remains to be done.
Challenging poverty
Authors: Underwood Sarah
Published: July 2008

Information and communication technologies are an important component in the generation of wealth. How can they help reduce poverty?
The profession of ITVoices of computing
Authors: Denning Peter J.
Published: July 2008

The choir of engineers, mathematicians, and scientists who make up the bulk of our field better represents computing than the solo voice of the programmer.
EducationPaving the way for computational thinking
Authors: Guzdial Mark
Published: July 2008

Drawing on methods from diverse disciplines---including computer science, education, sociology, and psychology---to improve computing education.
InterviewDonald Knuth: A life's work interrupted
Authors: Knuth Donald
Published: July 2008

In this second of a two-part interview by Edward Feigenbaum, we find Knuth, having completed three volumes of
The Art of Computer Programming
, drawn to creating a system to produce books digitally.
CTO Roundtable
Authors: Creeger Mache
Published: July 2008

Leaders in the storage world offer valuable advice for making more effective architecture and technology decisions.
The rise and fall of CORBA
Authors: Henning Michi
Published: July 2008

There's a lot we can learn from CORBA's mistakes.
The collaborative organization of knowledge
Authors: Spinellis Diomidis , Louridas Panagiotis
Published: July 2008

Why Wikipedia's remarkable growth is sustainable.
Computer science and game theory
Authors: Shoham Yoav
Published: July 2008

The most dramatic interaction between CS and GT may involve game-theory pragmatics.
PuzzledDelightful graph theory
Authors: Winkler Peter
Published: July 2008

Welcome to the new puzzle column. Each column will present three puzzles. The first two will have known (and usually elegant) solutions that will appear in the next issue of Communications. The third will be an open problem; good luck with that one.

Readers are encouraged to submit prospective puzzles for future columns to puzzled@cacm.acm.org.

We start with three delightful graph-theoretic puzzles. Here we go.
Remembering Jim
Authors: Ross Michael
Published: July 2008

Both melancholy and reverential, the Jim Gray Tribute at the University of California at Berkeley honored one of computer science's leading pioneers and visionaries.
Further developments in MacMahon's partition analysis (abstract only)
Authors: Andrews George E. , Paule Peter
Published: July 2008

P.A. MacMahon developed a calculus for producing generating functions of partitions constrained by linear inequalities relating the various parts of the partitions. Recently we have used MacMahon's method to find new classes of partitions whose generating functions are modular forms (Acta Arith., 126(2007), 281-294), and we have retrieved MacMahon's original project which was to prove his generating function formula for plane partitions. We shall report briefly on these topics and indicate new areas for exploration. In particular, we shall consider the modification of MacMahon's methods in which the inequalities relating the various parts of the partition take into account congruence constraints on the parts.
Solving multivariate linear recurrences in wedges (abstract only)
Authors: Petkovsek Marko
Published: July 2008

Many problems of combinatorial enumeration can be reduced to solving multivariate linear recurrences with constant coefficients in wedge-like domains. We survey some results on existence and uniqueness of solutions to such recurrences, on the algebraic nature of their generating functions, and on the methods for solving the corresponding functional equations, in particular the so-called kernel method. We also present a prototype Mathematica package for for obtaining explicit solutions when these generating functions are algebraic of low degree.
Multi-summation in difference fields (abstract only)
Authors: Schneider Carsten
Published: July 2008

In this talk we present recent symbolic summation tools based on difference field theory. The algorithmic ideas are illustrated by concrete examples that arise in the evaluation of Feynman integrals in perturbative quantum field theory.
Affine colored partitions (abstract only)
Authors: Billey Sara C. , Mitchell Stephen A.
Published: July 2008

We give a bijection between certain colored partitions and the elements in the quotient of an affine Weyl group modulo its Weyl group. By Bott's formula these colored partitions give rise to some partition identities. In certain types, these identities have previously appeared in the work of Bousquet-Melou-Eriksson, Eriksson-Eriksson and Reiner. In other types the identities appear to be new. Our main application is to determine the rationally smooth Schubert varieties in the affine Grassmannians. Several of the proofs are computer assisted. This is joint work with Steve Mitchell.
Computer-generated conjectures(!) and proofs(!!) in combinatorial game theory (II) (abstract only)
Authors: Thanatipanonda Thotsaporn "Aek"
Published: July 2008

This will be a follow up talk to my wonderful advisor Doron Zeilberger. People like to make fun of me for playing games. But playing games is fun and helps me do math better. I will give more examples of games and show how computers can make conjectures and prove theorems about them. (Received September 19, 2007).
Implementing Algebraic Combinatorics Some feedback from the development of MuPAD-Combinat (abstract only)
Authors: Thiery Nicolas M.
Published: July 2008

MuPAD-Combinat is an open-source algebraic combinatorics package for the computer algebra system MuPAD. Its main purpose is to provide an extensible toolbox for computer exploration, and to foster code sharing between researchers in this area. The development started in 2001, and it now contains functions to deal with most usual combinatorial classes (partitions, tableaux, decomposable classes, ...). It also supplies the user with tools for constructing new combinatorial classes and combinatorial (Hopf) algebras. As an application, it provides well-known combinatorial Hopf algebras like the algebra of symmetric functions and many generalizations. There is also experimental support for combinatorial Lie algebras, operads, (affine) Weyl groups, crystals, Schubert polynomials, invariant rings, ... Altogether, MuPAD-Combinat played a central role in 25+ publications with more than a dozen contributors. In this talk, we first demonstrate the main functionalities of the package and present some typical applications. Based on that, we discuss its design, successes and flaws, and its future. Feel free to contact the speaker if you would like to get some first hand experience through an informal tutorial, and bring your laptop if you have one.
Homologa efectiva y sucesiones espectrales (abstract only)
Authors: Ibáñez Ana Romero Ibáñez
Published: July 2008

Effective homology and spectral sequences are two different techniques of Algebraic Topology which can be used for the computation of homology and homotopy groups. In this work we try to relate both methods, showing that the effective homology method can also be used to produce algorithms computing some spectral sequences. In the thesis we focus our attention on two particular situations: spectral sequences associated with filtered complexes and the Bousfield-Kan spectral sequence.

The first part of the memoir is devoted to spectral sequences of filtered complexes, which under some good conditions converge to the homology groups of the initial complex. Making use of the effective homology method, we have developed several algorithms computing the different components of these spectral sequences: groups and differential maps in every stage, convergence level and filtration of the homology groups induced by the initial filtration. These algorithms have been implemented as a new module for the Kenzo system, a program of Symbolic Computation in Algebraic Topology, and can be used to determine two classical examples of spectral sequences, those of Serre and Eilenberg-Moore.

Other spectral sequences are not defined by means of filtered complexes. This is the case of the Bousfield-Kan spectral sequence, related with the computation of homotopy groups, which is studied in the second part of the thesis. Our algorithms for the computation of spectral sequences of filtered complexes cannot be applied, but the effective homology method can be useful again to develop a constructive version of the Bousfield-Kan spectral sequence. As a first necessary step, our main result is an algorithm computing the effective homology of the free simplicial Abelian group RX generated by a 1-reduced simplicial set X. This algorithm allows the construction of the levels 1 and 2 of the spectral sequence; for the computation of the higher "pages", we present a sketch of a new algorithm which is not finished yet. Furthermore, we include a proof of the convergence of the spectral sequence.
Computational complexity of numerical solutions of initial value problems for differential algebraic equations (abstract only)
Authors: Ilie Silvana
Published: July 2008

We investigate the cost of solving initial value problems for differential algebraic equations depending on the number of digits of accuracy requested. A recent result showed that the cost of solving initial value problems (IVP) for ordinary differential equations (ODE) is polynomial in the number of digits of accuracy. This improves on the classical result of information-based complexity, which predicts exponential cost. The new theory is based on more realistic assumptions.

The algorithm analyzed in this thesis is based on a previously published Taylor series method for solving a general class of differential algebraic equations. We consider DAE of constant index to which the method applies. The DAE is allowed to be of arbitrary index, fully implicit and have derivatives of order higher than one.

Similarly, by considering a realistic model, we show that the cost of computing the solution of IVP for DAE with the algorithm adopted and by using automatic differentiation is polynomial in the number of digits of accuracy. We also show that non-adaptation is more expensive than adaptation, giving thus a theoretical justification of the success of adaptivity in practice.

A particular case frequently arising in practical applications, the index-1 DAE, is treated separately, in more depth. On the other hand, an analysis of the higher-index DAE is significantly more complicated and applies to a wider class of problems. In both cases, continuous output is also given.

These results apply to many important problems arising in practice. We present an interesting theoretical application to polynomial system solving.
Brouwer's fixed point theorem (abstract only)
Authors: Benkiran Amine
Published: July 2008

"Brouwer's Fixed Point Theorem" was named after the Dutch mathematician "L. E. J. Brouwer". This theorem states that for every continuous function "f" mapped onto itself at a given interval, has at least one fixed point such that "f(x0) = x0". The proof of this theorem uses what is called "Sperner's Lemma" (by Emanuel Sperner), which would be the one focused on inorder to help understand "Brouwer's Fixed Point Theorem".
Models of population dynamics (abstract only)
Authors: Burkhart Brandon
Published: July 2008

This project explains the mathematical equations used to approximate species populations. The equations used are the exponential growth rate, logistic growth rate, and the predator-prey systems. The purpose is to show how the equations are taken from simple mathematical principles and assumptions. Basic techniques in Calculus and Linear Algebra are used to analyze the quantitative properties of solutions to the differential equation models.
The population biology of infectious diseases (abstract only)
Authors: Ebersole Caroline
Published: July 2008

In this poster, we are looking at differential equations that model a population with an infectious disease. Three different types of models are shown. The first model is the most primitive model, which does not effectively show how the population is spread in the population or does not take into account how difficult it would be to measure a viral population. The SIR model splits the population into three distinct categories: susceptible, infected, and removed. The SIRS model is similar except that individuals can return to the susceptible population after recovering from the virus. The SIRS model is further analyzed and a graph of the equilibrium points and nullclines.
An incremental algorithm for irreducible decompositions of monomial ideals (abstract only)
Authors: Gao Shuhong , Zhu Mingfu
Published: July 2008

Irreducible decompositions of monomial ideals are of interest in several areas. We present an incremental algorithm, which computes decompositions of ideals by adding one generator at a time. The new algorithm improves the Alexander dual and Scarf complex methods. A novel feature of the algorithm is that the intermediate storage used never exceeds the output size.
New algebraic design for better P2P Features (abstract only)
Authors: Guzide Osman , May Kenneth , Getz James , Edgeson Adam
Published: July 2008

Lately P2P application routing got interest and finding better routing and increasing performance and security is real challenge these days. Mostly research use overlay routing even using interconnection network design dynamically. Goal is to route a message to a destination whose IP address is not known which eliminates the need for large routing tables. Nevertheless, the overlay network could become wasteful because outgoing traffic may take a route longer than necessary. In this abstract, we propose a new design for P2P features. These new design is to combine physical and logical networks to reduce traffic and improving performance and security. This new design provides node organization for faster searching. Work used simulation program to show these new design better performance than existing design. Algorithm of new routing is defined mathematical algebraic model to show every case. Our next step is to actually improving localizing design with new overlay network design.
The RSA algorithm (abstract only)
Authors: Jones Josh
Published: July 2008

My project is a brief introduction for the RSA Algortim. This project will include a very brief history of where RSA originated, as well as how the RSA algorthim works. Following this, the mathematical proof of RSA is presented along with the two necessary theorems needed to prove RSA. The final portion of my presentation includes some of the potential threats to RSA and how to prevent these attacks, including a chart of the strength of RSA based on time required to crack RSA in MIPS-Years where the only factor is the size of the key.
Dethroning Fibonacci Sequence (abstract only)
Authors: Kelsey Michael A.
Published: July 2008

The purpose of this presentation is to demonstrate some properties and applications of Fibonacci numbers. We present Binet's Formula and its proof. By using Binet's Formula, we show that the Fibonacci sequence is not a special sequence. The Fibonacci sequence has a closed form solution which can be expressed analytically in terms of a bounded number of certain "well-known" functions, which indicates that the Fibonacci sequence is not unique.
Comparing acceleration techniques for the dixon and macaulay resultants (abstract only)
Authors: Lewis Robert
Published: July 2008

The Bezout-Dixon resultant method for solving systems of polynomial equations lends itself to various heuristic acceleration techniques, previously reported by the present author [6], which can be extraordinarily effective. In this paper we will discuss how well these techniques apply to the Macaulay resultant. In brief, we find that they do work there with some difficulties, but the Dixon method is greatly superior. That they work at all is surprising and begs theoretical explanation.
Automatic variable order selection for polynomial system solving (abstract only)
Authors: May John P. , Giesbrecht Mark , Roche Daniel , Maza Marc Moreno , Xie Yuzhen
Published: July 2008

The goal of a general purpose solver is to allow a user to compute the solutions of a system of equations with minimal interactions. Modern tools for polynomial system solving, namely triangular decomposition and Groebner basis computation, can be highly sensitive to the ordering of the variables. Our goal is to examine the structure of a given system and use it to compute a variable ordering that will cause the solving algorithm to complete quickly (or alternately, to give compact output). We explore methods based on the dependency graph of coincident variables and terms between the equations. Desirable orderings are gleaned from connected components and other topological properties of these graphs, under different weighting schemes. We present experimental results suggesting that these methods work well in practice.
Tricoloring as a corrective measure (abstract only)
Authors: McGrail Robert W. , Sharac Mary
Published: July 2008

This work presents a two-stage logic program to find tricolorings of a geometric braid [1]. This software is applied to data from the KnotData digital library of the Mathematica [5] symbolic computing system, revealing errors in that collection. The two algorithms presented below have been implemented in SWI-Prolog [4]. The first produces a crossing relation from a Knotdata braid word and the second searches for tricolorings given a crossing relation.
The concept of derivatives using abstract algebra (abstract only)
Authors: Prince Matthew
Published: July 2008

The purpose of this poster is to present the concept and proof of several rules of derivative using terminology and tools in abstract algebra. Four main tasks are fulfilled: prove that the differential operator D is a linear transformation, the product rule, and the degree of the derivative is one less than the degree of the original polynomial, and some corollaries and propositions. Some of the problems can be solved by using the limit definition introduced in calculus courses. The motivation for proof is presented in a format of showing the facts about polynomials and their derivatives using nothing but algebraic concepts and proof technique.
Origami and mathematics (abstract only)
Authors: Riley Sean
Published: July 2008

Mathematics applied to the design of an origami model can be used to develop the most efficient fold patterns; more simply stated the largest finished model compared to the unit dimensions of origami paper in unfolded shape. Based on the final chapter of Origami Design Secrets by R. J. Lang, a collaboration of algorithms which mathematically models most all aspects of what is happening to the piece of paper (set U) during origami transformation is presented. In order to understand what is meant by the symbolism of these algorithms, knowledge of discrete math, linear algebra, trigonometry, calculus, etc. College level mathematics is a necessity.
A solution for online entering and editing mathematical formulas (abstract only)
Authors: Su Wei , Cai Chuan , Wang Paul S. , Li Lian
Published: July 2008

The ability for users online creating and editing mathematical expressions is very important for Science Computing Systems, Science Communication Systems, and Web-based Mathematics Education Systems. Lanzhou university/China and Kent University/USA are jointly developing a mathematical expression editor. The editor MathEdit, implemented in JavaScript and MathML, is a web-based visual interactive editor for mathematical expressions. Figure 1 shows the end-user view of the MathEdit architecture. In MathEdit the MathML Content code is the core code of being edited mathematical expression. User actions, inserting, deleting and editing sub-expressions by mouse clicks and keyboard input, are treated as commands. The commands will invoke JavaScript functions in the command processing module to modify the MathML content code by revising DOM tree of expression. The MathML Content will synchronously convert to MathML Presentation code and Math Infix code. The user will intuitively see the changed math expression displayed by MathML Presentation.
On the functional decomposition of multivariate laurent polynomials (abstract only)
Authors: Watt Stephen M.
Published: July 2008

Determining whether a univariate polynomial may be written as the functional composition of two others of lower degree is a question that has been studied since at least the work of Ritt [1]. Algorithms by Barton and Zippel [2] and then by Kozen and Landau [3] have been incorporated in many computer algebra systems. Generalizations have been studied for functional decomposition of rational functions [4], algebraic functions [5], multivariate polynomials [6] and univariate Laurent polynomials [7].

We explore the functional decomposition problem for multivariate Laurent polynomials, considering the case f = g o h where g is univariate and h may be multivariate. We present an algorithm to find such a decomposition if it exists.

The algorithm proceeds as follows: First, a variable weighting is chosen to make the weighted degree zero term in f constant. The positive degree and negative degree parts of h are then reconstructed separately, in a manner similar to that of Kozen and Landau, but by treating the homogeneous collections of terms by grade rather than individual monomials. Then terms of the univariate polynomial g are reconstructed degree by degree using a generic univariate projection of h.
Divisibility tests (abstract only)
Authors: Wolfe Randall
Published: July 2008

Divisibility tests have always fascinated people. My project shows tricks of how you can tell if really large numbers can be divisible by smaller numbers. Modular arithmetic is utilized to find and analyze divisibility tests. Three methods (Ending Digits Test, Sum of Digits Test, and Alternating Sum of Digits Test) in which you can test divisibility of a number (a) by a number (d) and proofs are presented in this poster.
Computing minimal generators of integer matrix sequences (abstract only)
Authors: Yuhasz George , Kaltofen Erich
Published: July 2008

We describe a fraction free matrix Berlekamp/Massey algorithm. The algorithm behaves like a scalar algorithm by performing block eliminations through multiplication by adjoint matrices. The adjoints are computed using fraction free diagonalization. We also describe an interesting classification of the unique minimal generators of a linearly generated scalar integer sequence. A counter example to the scalar theorem is given for linearly generated integer matrix sequences.
An introduction to programming curriculum including elements of mathematics, art, and creative writing (abstract only)
Authors: Zeller Dean
Published: July 2008

During the Fall 2007 and Spring 2008 semesters, I tested a new style of teaching introductory programming in which graphics are covered early in the curriculum. Students gained familarity with the XY-Coordinate system used by most graphics packages. They used this system to create scalable (size and location) and color paraterizable graphics for use in other graphics. The mathematical properties of sine and cosine were used to generate points evenly distributed around a circle. Objects were collected into a function library to encourage collaboration. All this was finally used to create an interactive illustrated story. This new style of programming pedagogy can be applied to teaching middle- or high-school level mathematic.
Efficient order basis computation (abstract only)
Authors: Zhou Wei
Published: July 2008

Order basis (also known as 3/4-basis, minimal approximant basis), originally developed by Beckermann and Labahn in 1994 for rational approximation and interpolation problems, has recently been applied to many other important problems in polynomial matrix computation. These include column reduction, matrix inverse, determinant, and null space basis computation. Storjohann, in 2006, provided an efficient way to compute a part of order basis that is within a given degree bound. We extend Storjohann's result by providing a way to compute a complete order basis with a similar computational cos.
BASE: An Acid Alternative
Authors: Pritchett Dan
Published: July 2008

Web applications have grown in popularity over the past decade. Whether you are building an application for end users or application developers (i.e., services), your hope is most likely that your application will find broad adoption and with broad adoption will come transactional growth. If your application relies upon persistence, then data storage will probably become your bottleneck.
Ode to a Sailor
Authors: Carnes Donna
Published: July 2008

In memory of Jim Gray
Bridging the Object-Relational Divide
Authors: Russell Craig
Published: July 2008

Modern applications are built using two very different technologies: object-oriented programming for business logic; and relational databases for data storage. Object-oriented programming is a key technology for implementing complex systems, providing benefits of reusability, robustness, and maintainability. Relational databases are repositories for persistent data. ORM (object-relational mapping) is a bridge between the two that allows applications to access relational data in an object-oriented way.
ORM in Dynamic Languages
Authors: Richardson Chris
Published: July 2008

A major component of most enterprise applications is the code that transfers objects in and out of a relational database. The easiest solution is often to use an ORM (object-relational mapping) framework, which allows the developer to declaratively define the mapping between the object model and database schema and express database-access operations in terms of objects. This high-level approach significantly reduces the amount of database-access code that needs to be written and boosts developer productivity.
Review of "The Definitive Guide to the Xen Hypervisor" (Prentice Hall Open Source Software Development Series) David Chisnall, Prentice Hall PTR, 2007, $49.99, ISBN: 013234971X
Authors: Foxwell Harry J.
Published: July 2008

Review of "The Definitive Guide to the Xen Hypervisor" (Prentice Hall Open Source Software Development Series) David Chisnall, Prentice Hall PTR, 2007, $49.99, ISBN: 013234971X
Review of "Practical MythTV: Building a PVR and Media Center PC" Stewart Smith and Michael Still, Apress, 2007, $29.99, ISBN: 1590597796
Authors: Putnam Jeffrey
Published: July 2008

Review of "Practical MythTV: Building a PVR and Media Center PC" Stewart Smith and Michael Still, Apress, 2007, $29.99, ISBN: 1590597796
There’s a Lot of It About
Authors: Kelly-Bootle Stan
Published: July 2008

A lot of what, and about where? I hear you cry. One question at a time, I reply. First, there’s too much of everything these days, and, second, it’s happening all over. Furthermore, everybody’s doing it. As a contemporary Wordsworth might say: "The Web is too much with us, late and soon, getting and browsing we lay waste our powers." There is a glut of unfiltered information proving more dangerous than Alexander Pope’s "A Little Learning" where "shallow draughts intoxicate the brain."
A Homozygous L299P Mutation in the CYP11B1 Gene Leads to Complete Virilization in 46,XX Individuals with 11-Beta-Hydroxylase Deficiency
Authors: Riedl Stefan , Nguyen Huy-Hoang , Clausmeyer Susanne , Schulze Egbert , Waldhauser Franz , Bernhardt Rita
Published: July 2008

Background/Aim: 11-β-hydroxylase deficiency (11βOHD) is caused by CYP11B1 gene defects and leads to congenital adrenal hyperplasia associated with hypertension. Recently, a novel L299P mutation has been described in a compound heterozygous male individual. We observed two 46,XX siblings with a homozygous L299P mutation and investigated the functional properties of this CYP11B1 variant. Patients: The index patient from a consanguineous Turkish family showed complete external virilization and was diagnosed incidentally at the age of 19 months during hospital admission for severe combined bacterial (urosepsis) and viral (CMV and EBV) infection. The younger sibling was diagnosed at the age of 5 months. Their genital phenotype was identical and both demonstrated borderline elevated blood pressure. Results: Biochemical findings revealed 11βOHD. A homozygous L299P mutation of the CYP11B1 gene was detected. In vitro expression studies performed in HCT116 cells showed a markedly decreased CYP11B1 activity in the L299P mutant (1.6 ± 0.8%) for the conversion of 11-deoxycortisol to cortisol. Conclusions: Our study provides clear data on the functional properties and clinical phenotype in 46,XX individuals homozygous for this point mutation. Adrenal insufficiency might have contributed to the severe infectious disease that was present in the index patient at diagnosis.
Characteristics of Children with Premature Pubarche in the New York Metropolitan Area
Authors: Diaz Alejandro , Bhandari Sonal , Sison Cristina , Vogiatzi Maria
Published: July 2008

Background: Premature pubarche (PP) is defined as the appearance of pubic hair before 8 years in girls and 9 years in boys, without other signs of puberty. In the USA the prevalence of childhood overweight tripled between 1980 and 2000. An association between overweight and PP has been identified. Methods: We conducted a chart review to identify patients with the diagnosis of PP who were evaluated from July 2000 to October 2005. 38 patients, 29 females and 9 males, were studied. 16 were Caucasian, 11 African-American, 10 Hispanic, and 1 Arab. Age range was 4.3–9.8 years. Auxological features were analyzed. Results: Of the 38, 20 (52.6%) had a BMI >85th percentile. Increased weight was more common among females (62%) and Hispanics (80%). The study group was taller than expected Z = 1.11 ± 0.95 (TH Z = 0.34 ± 0.86). Among the 18 children who had bone age advancement >1.5 years, 10 (56%) had a predicted height <1 SD below the TH (p = 0.005). Conclusions: In this study we confirmed the correlation between weight gain and PP. We also found that when the bone age was advanced >1.5 years, the predicted adult height was affected.