Symbolic Step Research Articles

The European Parliament in the 2000 IGC and the Constitutional Treaty negotiations: from loser to winner

ABSTRACT Why did two rounds of EU constitutional reform held within a five-year period yield very different results? The 2000 IGC resulted in the modest Treaty of Nice, whereas the 2002–04 round drafted the Constitutional Treaty which, although it did not involve major substantive changes, did mark a major symbolic step forward. This article argues that the change in outcomes can to a large degree be explained by the change in negotiating structure due to the use of a convention that drafted most of the Constitutional Treaty's text, creating a context which privileged MEPs. While the outer bounds of the possible were set by governments, the EP was able to build coalitions around ambitious yet realistic positions, leading to a final text that was a major symbolic step forward.

Playing politics with the mobile phone in Nigeria: civil society, big business & the state

On 19 September 2003, mobile phone subscribers in Nigeria took the unprecedented step of switching off their handsets en masse. The subscribers took this symbolic step in protest against perceived exploitation by the existing mobile phone companies. Among other things, they were angered by allegedly exorbitant tariffs, poor reception, frequent and unfavourable changes in contract terms, and arbitrary reduction of credits. Among other critical questions, the protest helped bring into focus the following: How is (mobile) technology shaping the democratic momentum in Nigeria? How useful is technology as a mechanism for socio-economic empowerment? Using the boycott as backdrop, this paper provides some tentative answers. It is argued that the boycott ought to be appraised, first, in the context of existing mistrust between citizens and transnational big business in Nigeria; and second, against the background of difficult state-society intercourse which has mostly been characterised by the latter’s suspicion of the state’s connivance with the corporate establishment. Furthermore, because it gives ‘civil society’ a combined cause and instrument of protest, mobile phones in the Nigerian context appear to presage the emergence of a new social space of politics and agitation. The paper underscores an ordinarily subsumed ‘class’ dimension to the protest, illustrating how a struggle about the interests of a section of ‘civil society’ may have a potential for enlarging the larger ‘political space’.

Validated Linear Relaxations and Preprocessing: Some Experiments

Based on work originating in the early 1970s, a number of recent global optimization algorithms have relied on replacing an original nonconvex nonlinear program by convex or linear relaxations. Such linear relaxations can be generated automatically through an automatic differentiation process. This process decomposes the objective and constraints (if any) into convex and nonconvex unary and binary operations. The convex operations can be approximated arbitrarily well by appending additional constraints, while the domain must somehow be subdivided (in an overall branch-and-bound process or in some other local process) to handle nonconvex constraints. In general, a problem can be hard if even a single nonconvex term appears. However, certain nonconvex terms lead to easier-to-solve problems than others. Recently, Neumaier, Lebbah, Michel, ourselves, and others have paved the way to utilizing such techniques in a validated context.In this paper, we present a symbolic preprocessing step that provides a measure...

Building three-dimensional ribonucleic acid structures

MC-Sym is an intelligent computer system that builds 3D ribonucleic acid structures from low-resolution data by combining symbolic and numerical computations. Specifically, the symbolic step generates all-atom sketches of 3D structures that nonlinear optimization methods can refine in a second step.

Teaching spline approximation techniques using maple

Using Computer Algebra Systems (CAS)-such as MAPLE-in teaching and learning mathematical concepts is a great challenge both from a didactical and a scientific point of view. We have to rewrite our traditional paper based teaching materials for interactive and living electronic worksheets, Only few statements and principles have to be acquired by the learner and the teacher from the CAS and after they can visualise, make animations modify quickly the program data, perform symbolic and numeric calculations step by step and in the whole, and verify deductions on their own. The author prepared Maple worksheets for teaching different types of function approximating techniques, such as interpolation-, least square-, spline and uniform approximation methods for post-graduate mechanical engineering students. In this paper we want to demonstrate how can we keep and improve the famous problem solving principles and rules given by G. Polya and R. Descartes (Polya 1962), when we use the capabilities of CAS. The education principles active learning, motivations and the successive phases are getting new meaning in the CAS. Our examples are always concerning with spline functions. Handling the formulas, calculating values and giving proofs are always in the form of Maple statements.

Border Cooperation between China and Vietnam in the 1990s

In spring 1989, several thousand Vietnamese living in the northern border region waded across the Beilun River and entered China. This wave of people came carrying such goods as rice, pieces of copper, scrap iron, and the like, which they traded on the streets of their destination, the frontier town of Dongxing located in China's Guangxi Province. These traders were followed soon thereafter by many thousands of more Vietnamese who chose to celebrate the Tet holidays then underway by shopping in Dongxing for a variety of consumer commodities. The Vietnamese at Dongxing were not alone, for many of their compatriots also had taken the holiday occasion to make similar trips across the border and enter Guangxi. These spring developments were representative of the overall trend in the resumption of economic and trading activities along the border between China and Vietnam that unfolded slowly at the end of 1988 and start of 1989. Such activities had come to a halt 10 years earlier, a casualty of the SinoVietnam War. The 1990s would see expanding contact and cooperation along the frontier that culminated in the December 30, 1999, signing of a treaty by the foreign ministers of China and Vietnam that demarcated the land border between the two countries. This was an important symbolic step signifying the attempt by both sides to place the normalization of relations on a stable and permanent footing and the logical outcome of a decade marked by cordial relations in the border regions. The purpose of this article is to describe the process of normalization on the border during the 1990s. It first outlines the general geography of the

Some Results on Structure Prediction in Sparse $QR$ Factorization

In $QR$ factorization of an $m \times n$ matrix $A$ ($m \geq n$), the orthogonal factor $Q$ is often stored implicitly as an $m \times n$ lower trapezoidal matrix $W$, known as the Householder matrix. When the sparsity of $A$ is to be exploited, the factorization is often preceded by a symbolic factorization step, which computes a data structure in which the nonzero entries of $W$ and $R$ are computed and stored. This is achieved by computing an upper bound on the nonzero structure of these factors, based solely on the nonzero structure of $A$. In this paper we use a well-known upper bound on the nonzero structure of $W$ to obtain an upper bound on the nonzero structure of $Q$. Let $U$ be the matrix consisting of the first $n$ columns of $Q$. One interesting feature of the new bound is that the bound on $W$'s structure is identical to the lower trapezoidal part of the bound on $U$'s structure. We show that if $A$ is strong Hall and has no zero entry on its main diagonal, then the bounds on the nonzero structures of $W$ and $U$ are the smallest possible based solely on the nonzero structure of $A$. We then use this result to obtain corresponding smallest upper bounds in the case where $A$ is weak Hall, is in block upper triangular form, and has no zero entry on its main diagonal. Finally, we show that one can always reorder a weak Hall matrix into block upper triangular form so that there is no increase in the fill incurred by the $QR$ factorization.

ThewwTfactorization of dense and sparse matrices

The WW T factorization was introduced in [18] as a permuted form of the Cholesky LL T factorization. In this paper, we present a direct proof for the existence of an other WWT factorization of a symmetric positive definite matrix. Next, we propose an algorithm for computing the W factor. Finally, we study the symbolic factorization step in computing the WW T factorization of sparse matrices.

Indian Lives: The Defining, the Telling

THOUGH THEY ARE CERTAINLY NOT INFALLIBLE INDICES TO CANON revision, the annual eight-hundred sessions of the MLA Convention do, at least, suggest trends. The distribution of sessions during the past few years and American Indian literature's recent elevation from discussion group to division status (a key bureaucratic and symbolic step) indicate a growing, though highly selective, interest in Native American literature. Most of the sessions and individual papers focus on fiction and autobiography. This imbalance was predictable. When English professors incorporate new texts into their courses and scholarship, they incline toward familiar forms and accessible and recognizable texts. Certainly modem fiction fits that formula. Novels by N. Scott Momaday, Leslie Marmon Silko, Louise Erdrich, and James Welch are respected and are, for most English teachers,

Symbolic Givens Reduction and Row-Ordering in Large Sparse Least Squares Problems

In the solution of large sparse least squares problems by Givens factorization, a preliminary symbolic step that determines a good processing order and a data structure for the matrix factor is used. In this paper, it is shown that a processing order equivalent to sequential processing by rows can be as good as any processing order using a single pivot row in each column. A notion of local acceptability in row-ordering is introduced and shown to reduce fill globally. Row-orderings satisfying this notion are essentially equivalent to sequential processing by rows and the nature of intermediate fill produced makes implicit representation of fill possible. This forms the basis for a symbolic Givens reduction algorithm that operates in a fixed data structure.