Complementary Terms Research Articles

Process ecology

A traditional presupposition in science is that nature ultimately is simple and comprehensible. Accordingly, ‘theory reduction’ is a primary goal in much of ecosystems science – the belief, for example, that ecosystem development can be described by a single covering principle. Recently, however, the theory of complex adaptive systems has challenged the assumption that simplicity is ubiquitous. While students of complexity theory recognize individual constraints that orient ecosystem development, they are skeptical of the urge to identify a single, monistic principle that governs all ecosystem behavior. One approach, called ‘process ecology’, depicts ecosystem development as arising out of at least two antagonistic trends via what is analogous to a dialectic: one direction is the entropic tendency towards disorganization and decay, which can involve singular events that defy quantification via probability theory. Opposing this ineluctable drift are self-entailing configurations of processes that engender positive feedback or autocatalysis, which in turn imparts structure and regularity to ecosystems. The status of the transactions between the two trends can be gauged using information theory and is expressed in two complementary terms called the system ‘overhead’ and ‘ascendency’, respectively. Process ecology provides an opportunity to approach some contemporary enigmas, such as the origin of life, in a more accommodating light.

The Magnetokinematical Effect

A new aspect of the classical concept of macroscopic magnetism is considered. The notion ‘electrokinematics’ was used by James Clerk Maxwell but, by contrast, until recently the complementary term ‘magnetokinematics’ has been out of use. An empirical proof of the existence of an unknown magnetokinematical effect is given.

Continuous symmetries and constitutive laws of dissipative materials within a thermodynamic framework of relaxation: Part I: Formal aspects

An analysis of the continuous symmetries of the constitutive laws of inelastic materials written within a thermodynamical framework of relaxation is performed. This framework relies on the generalization of Gibb’s relationship outside the equilibrium of a uniform system, and the use of the fluctuation theory to model the material dissipation due to its internal microstructure change [Cunat, C., 2001. The DNLR approach and relaxation phenomena. Part I – Historical account and DNLR formalism. Mech. Time-depend. Mater. 5, 39–65]. The approach leads to a viscoelastic like formulation for small deformations, and changes gradually for finite strains towards elastoviscoplasticity (with or without damage) via a dependence of characteristic times with the loading path, in a way similar to the endochronic approach developed by Valanis [Valanis, K.C., 1975. On the fundations of the endochronic theory of viscoplasticity. Arch. Mech. 27, 857–868]. The present thermodynamic framework has been previously applied to elastoviscoplastic materials under cyclic and non-proportional loadings [Dieng, L., Abdul-Latif, A., Haboussi, M., Cunat, C., 2005b. Cyclic plasticity modeling with the distribution of non-linear relaxations approach. Int. J. Plasticity 21, 353–379]. The constitutive laws split into the state laws relating intensive variables (thermodynamics forces) to extensive-like variables, and the complementary evolution laws of the internal variables associated to the dissipative mechanisms. An interpretation of a non-equilibrium thermodynamic approach of irreversible processes in terms of an extremum principle is proposed, associated to a Lagrangian functional. It is shown that one possible choice for the Lagrangian kernel is the material derivative of the internal energy density, augmented by a complementary term that accounts for the evolution laws of the internal variables. Interpreting the material behavior during the non-equilibrium evolution as the Euler–Lagrange equations of the resulting action integral, a differential condition expressing both the local and variational symmetries encapsulated into the Lagrangian formulation is formulated. It is further shown that both symmetry conditions are fully equivalent along the optimal path corresponding to the satisfaction of the constitutive laws. In terms of both practical and methodological aspects, the predictive nature of the symmetry analysis is highlighted, as a systematic tool for the exploitation of the constitutive response. Its performance and utility are exemplified by the construction of a time–temperature equivalence principle for a dry viscous polymer (PA66); the calculated shift factor is shown to well agree with the empirical shift factor given by Williams–Landel–Ferry (WLF) expression. A systematic interpretation of the calculated symmetry groups of the constitutive laws in terms of master curves for various plastic and viscoplastic materials shall be presented in a forthcoming contribution.

A Variational Model for Object Segmentation Using Boundary Information and Shape Prior Driven by the Mumford-Shah Functional

In this paper, we propose a new variational model to segment an object belonging to a given shape space using the active contour method, a geometric shape prior and the Mumford-Shah functional. The core of our model is an energy functional composed by three complementary terms. The first one is based on a shape model which constrains the active contour to get a shape of interest. The second term detects object boundaries from image gradients. And the third term drives globally the shape prior and the active contour towards a homogeneous intensity region. The segmentation of the object of interest is given by the minimum of our energy functional. This minimum is computed with the calculus of variations and the gradient descent method that provide a system of evolution equations solved with the well-known level set method. We also prove the existence of this minimum in the space of functions with bounded variation. Applications of the proposed model are presented on synthetic and medical images.

Proposal of New Perturbation Method with Complementary Term for Dynamic Characteristics Prediction of Modified Structure

Because of the large scale model of the finite element method in these days, it is required to find the method, which can be applied to the optimal analysis, to minimize the time for estimate of dynamic characteristics when changing the structure. We develop here a new perturbation method with complimentary term which is effective to this purpose. Here we show by both numerical and theoretical analysis that the accuracy of the estimate is greatly improved, including the case of without the lower modes, by using the complimentary vector adjusted to the change of structure and input style, which is obtained by Ma-Hagiwara modal method. We can show the possibility by using the method proposed here to reduce the analysis time drastically when the structure is even much changed on a large scale model.

Modified Two-Scale Model for Electromagnetic Scattering fromthe Non-Gaussian Oceanic Surface

Based on the skewness of sea waves, a modified two-scale model isdeveloped for the non-Gaussian sea surface scattering. In this newmodel, a complementary term is added to the first-order scatteringcoefficient of the classical small perturbation method (SPM), theadditional part is proportional to the surface bispectrum and it is thecritical part in explaining the scattering difference between upwindand downwind observations. Meanwhile, the effects of the shadowingfunction of the anisotropic surface, the curvature of the surface arealso taken into account. The numerical results show the theoreticalestimates obtained are consistent with the experimental result, and theinfluence of the wind speed, the trend and the incident frequency onthe backscattering coefficients from the non-Gaussian oceanicsurface is discussed in detail.

An indolence of the heart

Walter Benjamin’s understanding of allegory as developed in The Origin of German Tragic Drama, and whose genius is Dürer’s image of winged melancholy, stands in diametric opposition to the symbolic unity proposed in Michael Fried’s emblematic modernist essay “Art and Objecthood”. The complex cultural tensions and expectations defined by these texts—as well as the complementary terms symbol and allegory—can be understood as a function of the category of time, and it is this temporal problematic that this essay situates with reference to the contingent art forms of the late 1960s and early 1970s.

A new approach for sizing stand alone photovoltaic systems based in neural networks

Several methods for sizing stand alone photovoltaic (pv) systems has been developed. The more simplistic are called intuitive methods. They are a useful tool for a first approach in sizing stand alone photovoltaic systems. Nevertheless they are very inaccurate. Analytical methods use equations to describe the pv system size as a function of reliability. These ones are more accurate than the previous ones but they are also not accurate enough for sizing of high reliability. In a third group there are methods which use system simulations. These ones are called numerical methods. Many of the analytical methods employ the concept of reliability of the system or the complementary term: loss of load probability (LOLP). In this paper an improvement for obtaining LOLP curves based on the neural network called Multilayer Perceptron (MLP) is presented. A unique MLP for many locations of Spain has been trained and after the training, the MLP is able to generate LOLP curves for any value and location.

A Quasi-Dual Function Method for Extracting Edge Stress Intensity Functions

We present a method for the computation of the coefficients of singularities along the edges of a polyhedron for second-order elliptic boundary value problems. The class of problems considered includes problems of stress concentration along edges or crack fronts in general linear three-dimensional elasticity. Our method uses an incomplete construction of three-dimensional dual singular functions, based on explicitly known dual singular functions of two-dimensional problems tensorized by test functions along the edge and combined with complementary terms improving their orthogonality properties with respect to the edge singularities. Our method is aimed at the numerical computation of the stress intensity functions. It is suitable for a postprocessing procedure in the finite element approximation of the solution of the boundary value problem.

The African Stakes of the Congo War

John F. Clark, ed. The African Stakes of the Congo War. New York: Palgrave Macmillan, 2002. xv + 249 pp. Maps. Index. $55.00. Cloth. Long awaited to fill the gap in our knowledge of the ongoing conflict in the Democratic Republic of Congo (DRC) and provide a clear examination of the implications of what has been dubbed first continental The African Stakes of the Congo War offers a collection of well-balanced and meticulously wrought essays. The four-part volume goes well beyond the urgent necessity of documenting the havoc wreaked in the Congo since Mobutu's demise. Suggestive and pertinent as these thirteen essays are, however, they obviously cannot pretend to embrace the totality of the Congolese tragedy. Clark's introductory chapter skillfully provides the common threads that run through the book by defining the conflict in terms of several premises: the dominant historical pattern of the scramble for Congo's resources; the collapse and Mobutu's extractive state legacy; the larger trend of warlordism (spurred by Western corporations' greed for Africa's resources) that has swept across the continent since the 1990s; and the political vacuum left by the end of the cold war. In the first part, Crawford Young (chapter 2) provides a useful postcolonial taxonomy of Africa's conflicts that rests on the old-fashioned, yet pertinent, Weberian model of stateness. Next, Jermaine McCalpin traces the origins of the Congo war from the Leopoldian red rubber terror to the tumultuous botched independence and to Mobutu's protracted and kleptocratic dictatorship. Nevertheless, attributing the inevitability of the Congo war to these historical developments tends to put unreasonably high premium on the past while neglecting both the timing and the recent events that have unfolded in the Great Lakes area in the aftermath of the Rwandan genocide. The second and third parts look at the external belligerents of the Congo war, those who intervened to support the Kabila regimes as well as those who sided with the rebel factions to challenge Mobutu's successors. Kevin Dunn (chapter 4) sets the tone by outlining the strategies employed by Laurent Kabila to keep his regime in power, strategies that could be categorized in complementary terms of reliance on foreign alliances and distrust of local and internal constituencies. Thomas Turner (chapter 5) rightfully ties Angola's military intervention in the not only to Luanda's decades-old fight against Savimbi's UNITA rebel movement but also to a broader hegemonic strategy that first unfolded in neighboring CongoBrazzaville when Angolan troops helped Sassou's beleaguered forces crush government militias. Zimbabwe's intervention, in contrast, is lauded by Martin Rupiya (chapter 6) as a selfless, legal, pan-Africanist and SADC-sanctioned mission that saved the from falling into the hands of Rwandan and Ugandan troops even as it burdened Zimbabwe's cash-strapped economy. Although evidence suggests that Zimbabwe's motivations might have been less benevolent, Rupiya lambastes such conspiracy theories as an unrelenting campaign depicting Zimbabwe's involvement as illegitimate, ill-advised, and based on personal quests for enrichment from the gold and diamonds in the DRC (100). …

What's the Matter?

What's the Matter?

A new algorithm for a robust solution of the fully dynamic Saint-Venant equations

A new procedure for the numerical solution of the fully dynamic shallow water equations is presented. The procedure is a fractional step methodology where the original system is split into two sequential ones. The first system differs from the original one because of the head gradient term, that is treated as constant and equal to the value computed at the end of the previous time step. The solution of this system, called kinematic, is computed in each element using a spatial zero order approximation for both the heads and the flow rates by means of integration of single ODEs. The second system is called diffusive, contains in the momentum equations only the complementary terms and can be easily solved using implicit methods. The major advantages of the methodology are: (1) it guarantees mass conservation; (2) it shows unconditional stability with respect to the Courant number; (3) it can be applied to initially dry domains; (4) it can be applied to closed conduits without the help of the Preissman approximation.

Diagnostic Model and Analysis of the Surface Currents in the Tropical Pacific Ocean

Abstract A diagnostic model of the tropical circulation over the 0–30-m layer is derived by using quasi-linear and steady physics. The horizontal velocity is directly estimated from sea surface height (TOPEX/Poseidon), surface vector wind (SSM/I) and sea surface temperature (AVHRR + in situ measurements). The absolute velocity is completed using the mean dynamic height inferred from the World Ocean Atlas (WOA). The central issue investigated in this study is the more accurate estimate of equatorial surface currents relative to prior satellite-derived method. The model formulation combines geostrophic, Ekman, and Stommel shear dynamics, and a complementary term from surface buoyancy gradient. The field is compared with velocity observations from 15-m-depth buoy drifter and equatorial Tropical Ocean–Atmosphere (TAO) current meters. Correlations with TAO data on the equator are much higher in the eastern Pacific cold tongue than before. The mean field in the cold tongue is also much more accurate, now showin...

Generalization of Itô's formula for smooth nondegenerate martingales

In this paper we prove the existence of the quadratic covariation [(∂F/∂x k)(X), X k] for all 1⩽ k⩽ d, where F belongs locally to the Sobolev space W 1,p( R d) for some p> d and X is a d-dimensional smooth nondegenerate martingale adapted to a d-dimensional Brownian motion. This result is based on some moment estimates for Riemann sums which are established by means of the techniques of the Malliavin calculus. As a consequence we obtain an extension of Itô's formula where the complementary term is one-half the sum of the quadratic covariations above.

Taux de restitution de l'énergie pour une poutre courbe mince

Let a thin two-dimensional domain be in a plane strains state. It is made of two materials separated by a regular curvilinear interface along of which a crack is assumed to propagate. The expression of the energy release rate is derived in local coordinates using the so-called θ-method. It is shown that there are complementary terms related to the derivation of the local metric.

War and geopolitics ‐ really together again?

Geopolitics and war are complementary terms, unified processes. Against the idea of deterritorialized world in the fourth ‘new world order’ stay basic unchangeable constants: space as a given, territorially as behaviour, and territory as the central value through which other values of political being could be expressed. Space persists to be territorialized and, especially Euro‐Asian land, divided into geostrategical realms, geopolitical regions, and states and regions ‘in between’, gateways, shatterbelts etc. However, actual re‐ordering means keeping attainable in the nick of time in one way or another ‐ ‘peaceful’, ‘peacekeeping’, ‘peacemaking’. It really seems that the geopolitics and war are returned together, exactly like they should be.

INSCRIBING THE ESSENTIALS: CULTURE AND THE BODY IN MING-QING FICTION

The figure of the man or woman urinating is a common motif in Ming-Qing fiction. In one anecdote by Yuan Mei (1716–1798), a woman goes outside one night to empty her bladder and sets in motion a chain of events that ends with her own death. In Xia Jingqu's lengthy novel (1705–1787) Yesou puyan (A country codger's words of exposure), the male protagonist urinates on a corpse and brings the dead man back to life. The stark contrast between the effect of male and female urine in these roughly contemporaneous works of fiction exemplifies the different relationship between social order and the male and female body in the late-imperial Chinese narrative tradition. While urination scenes have been discussed either in terms of humor or as narrative interstice used to link scenes, these voluntary and involuntary discharges from the body also illustrate the impossibility of absolute self-containment. In symbolic terms, the individual body can serve as model for any bounded social system so that ruptures in its surface signal the breakdown of that system. As we shall see, the spectacle of the leaking female body is a particularly powerful symbol of transgression in the Chinese context, not only because a woman's urine evokes the possibility of menstruation and its dangerous polluting powers (Ahern 1975; Seaman 1974). More powerfully, the image undermines the ritual injunction to maintain a boundary between nei and wai, a pair of complementary terms that simultaneously refers to architectural boundaries between inner and outer and the social distinctions between private and public, by exposing the bodies of cloistered women to the reader's gaze and metonymically invoking female desire. As will become clear, urination frequently carries overtones of desire. In contrast, the image of a man urinating typically functions as a neutral structural link or, less frequently, initiates a positive event.

Two dimensional transient fundamental solution due to suddenly applied load in a half-space

A transient Green function due to suddenly applied line loads in an isotropic and homogeneous half-space is reported in this paper. The derivation of the half-space Green function in the Laplace and the Fourier transform spaces is first reviewed. Following an explicit inversion of the Fourier transform, the inverse Laplace transform is implemented along the contour integral on the p-complex plane in an integral form. The half-space Green function consists of full-space Green functions and a singularity-free complementary term. It can be easily incorporated into current transient boundary elements using the transient full-space Green function. Combined with finite elements, the half-space Green function can be used in a hybrid procedure to solve transient half-space problems without discretization of the free surface. Numerical results are presented to illustrate transient wave propagation in a half-space.

Accuracy and conservation properties in numerical integration: the case of the Korteweg-de Vries equation

When numerically integrating time-dependent differential equations, it is often recommended to employ methods that preserve some of the invariant quantities (mass, energy, etc.) of the problem being considered. This recommendation is usually justified on the grounds that conservation of invariant quantities may ensure that the numerical solution possesses some important qualitative features. However there are cases where schemes that preserve invariants are also advantageous in that they possess favourable error propagation mechanisms that render them superior from a quantitative point of view. In the present paper we consider the Korteweg-de Vries equation as a case study. We show rigorously that, for soliton problems and at leading order, the error of conservative schemes consists of a phase error that grows linearly with time plus a complementary term that is bounded in the $H^1$ norm uniformly in time. For ‘general’, nonconservative schemes the error involves a linearly growing amplitude error, a quadratically growing phase error and a complementary term that grows linearly in the $H^1$ norm. Numerical experiments are presented.

An extended syllogistic system with conjunctive and complementary terms, and its completeness proof

AbstractAristotle's (Categorical) Syllogism is a logic system in which a new proposition is derived from several propositions stating the relation among “terms” (corresponding to common nouns). It can directly treat a term itself, and has a unique character different from predicate logic where its semantics is constructed based on “individuals”. Therefore, syllogism has several advantages as a logic system for processing a general knowledge such as one expressed by a natural language. However, the expressive ability of classical syllogism is poor. In particular, it can treat only atomic terms as primitive objects. Previously, we proposed an extended syllogistic system with the term operator of conjunction. This paper is a further extension of that system. We introduce a syllogistic system which can treat compound terms produced by using the term operators of conjunction, disjunction and complementation. A set of axioms and an arithmetic interpretation for this system are given, and its completeness is proved.