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ESC/Java2 is a tool that statically detects errors in Java programs and that uses the Java Modeling Language (JML) as its annotation language. ESC/Java2 can modularly reason about the code of a Java Web-based Enterprise Application (WEA) and uncover potential errors. In this paper, we assessed the effectiveness of ESC/Java2 at helping developers increase WEA quality by detecting design and implementation issues.

We mainly introduce some weak versions of the $M_{1}$-spaces, and study some properties about these spaces. The mainly results are that: (1) If $X$ is a compact scattered space and $i(X)\leq 3$, then $X$ is an $s$-$m_{1}$-space; (2) If $X$ is a strongly monotonically normal space, then $X$ is an $s$-$m_{2}$-space; (3) If $X$ is a $\sigma$-$m_{3}$ space, then $t(X)\leq c(X)$, which extends a result of P.M. Gartside in \cite{CP}. Moreover, some questions are posed in the paper., Comment: 8 pages

This paper analyzes the link between the economic fundamentals of the global crude oil markets and the oil futures risk premium. The compensation for risk required by speculators in the oil futures market is modelled as part of the endogenous transmission of oil price shocks. The empirical approach is based on a Structural Vector Autoregressive model of the international market for crude oil. The dynamic response functions show a negative relationship between the risk premium and the real price of oil, triggered by shocks to economic fundamentals. Moreover, the expected returns of a long futures investment are largely explained by a specific shock component related to oil speculators and a shift in the global demand for crude oil.

This paper lays theoretical and software foundations for a World Wide Argument Web (WWAW): a large-scale Web of inter-connected arguments posted by individuals to express their opinions in a structured manner. First, we extend the recently proposed Argument Interchange Format (AIF) to express arguments with a structure based on Walton's theory of argumentation schemes. Then, we describe an implementation of this ontology using the RDF Schema Semantic Web-based ontology language, and demonstrate how our ontology enables the representation of networks of arguments on the Semantic Web. Finally, we present a pilot Semantic Web-based system, ArgDF, through which users can create arguments using different argumentation schemes and can query arguments using a Semantic Web query language. Manipulation of existing arguments is also handled in ArgDF: users can attack or support parts of existing arguments, or use existing parts of an argument in the creation of new arguments. ArgDF also enables users to create new argumentation schemes. As such, ArgDF is an open platform not only for representing arguments, but also for building interlinked and dynamic argument networks on the Semantic Web. This initial public-domain tool is intended to seed a variety of future applications for authoring, linking, navigating, searching, and evaluating arguments on the Web.

Metadata only record Increased population pressure has led to attempts to reclaim some to the ten million square miles of Africa in which tsetse fly occur. The paper traces the occurrence of tsetse fly, and its impact on cattle. In tsetse free areas, cattle biomass increases with rainfall, but in countries partially infested with tsetse, no clear relationship with rainfall is shown, and countries with high incidence of tsetse have low cattle biomasses whatever the rainfall. The author concludes that if tsetse fly were to be eradicated, this could lead to an increase in the biomass of cattle in these regions. He cautions that this could entail the degradation of much of the land as has occurred in tsetse free areas, and then the decline in productivity; he proposes that research into optimum carrying capacity should be carried out in order to maximize production. He asserts that optimum carrying capacity predictions derived from meteorological statistics have some validity, and would be useful for desirable stocking levels for economic assessment of tsetse eradication programs, and for livestock development projects generally. -b/m

Cooperative communication (CC) is a technique that exploits spatial diversity allowing multiple nodes to cooperatively relay signals to the receiver so that it can combine the received signals to obtain the original message. CC can be combined with topology control to increase connectivity at the cost of a small increase in energy consumption. This work focuses on exploring CC to improve the connectivity with a sink node in ad hoc wireless networks. More precisely, this work proposes a new technique, named CoopSink, that combines CC and topology control techniques to increase connectivity to a sink node while ensuring energy-efficient routes. Simulation results show that connectivity and routing to the sink cost can be improved up to 6.8 and 2.3 times, respectively, when compared with other similar strategies.

In a first step this article gives some definitional properties of a linguistic concept of narrative and discusses a few of the data provided by the papers in the first part of this volume in relation to this concept. Narration is taken as an interactive process, which is accomplished jointly by narrator and listener and which is always part of a larger frame of activities. This view has certain consequences as to the way in which narrative data should be elicited, documented and analyzed in all the relevant disciplines. These consequences are discussed briefly. In a second step, three different types of narration distinguished on the basis of formal properties of the narrative interaction are introduced. The ‘replaying’ conversational narrative, the report and the brief statement are described; emphasis is put upon the formal characteristics of the replaying discourse pattern: direct speech, historical present, imitation, evaluation and high degree of detailedness. In a third step, a cognitive aspect of story-telling is dealt with, namely the features of information processing typical of the transformation which an event undergoes when it becomes the referent of conversational narrative. In a final step, the methodological consequences of a linguistic theory of narrative as has been outlined before are shown in a sample analysis of one of the narratives documented by Wiedemann (pp. 43–55).

The motivation of this paper is 3-fold. Firstly, we apply a Multi-Layer Perceptron (MLP), a Recurrent Neural Network (RNN) and a Psi-Sigma Network (PSN) architecture in a forecasting and trading exercise on the EUR/USD, EUR/GBP and EUR/CHF exchange rates and explore the utility of Kalman Filter, Genetic Programming (GP) and Support Vector Regression (SVR) algorithms as forecasting combination techniques. Secondly, we introduce a hybrid leverage factor based on volatility forecasts and market shocks and study if its application improves the trading performance of our models. Thirdly, we introduce a specialized loss function for Neural Networks (NNs) in financial applications. In terms of our results, the PSN from the individual forecasts and the SVR from our forecast combination techniques outperform their benchmarks in statistical accuracy and trading efficiency. We also note that our trading strategy is successful, as it increased the trading performance of most of our models, while our NNs loss function seems promising.

This paper looks at a model of a labour market where labour contracts concerning job content cannot be written completely and employers have control over the effort level of workers. It is shown that in such a model if workers face strictly positive mobility costs in moving from one firm to another, then, however small these costs, the equilibrium level of workers' utility will be that obtainable by not working. In some situations this will be the subsistence level. This is the Marxian feature of the model. This result is independent of aggregate labour market conditions. Consequently, the model can be thought of as one where there is an endogenously fixed real wage. This is the Keynesian feature. It is shown that there is zero effective excess demand for labour in equilibrium so there are few incentives for employers to relinquish control over effort levels.

In this paper we investigate the evolution of a class of cosmologies fuelled by quintom dark energy and dark matter. Quintom dark energy is a hybrid of quintessence and phantom which involves the participation of two reals scalar fields playing the roles of those two types of dark energy. In that framework we examine from a dynamical systems perspective the possibility that those fields are coupled among them by considering an exponential potential with an interesting functional dependence similar but not identical to others studied before. The model we consider represents a counterexample to the typical behavior of quintom models with exponential potentials because it admits either tracking attractors ($w=0$), or phantom attractors ($w, Comment: revtex4, 7 pages, 6 figures

Global functions of cellular automata on state spaces equipped with the Cantor topology are well characterized by the Curtis–Hedlund–Lyndon theorem. In this paper, we develop a characterization of global functions of cellular automata on Z, if the state space is equipped by Weyl and Besicovitch topology. The necessary and sufficient condition for a function to be the global map of a cellular automaton is (1) a strong localization property, a condition that strengthen Lipschitz continuity, (2) the set of (Cantor) periodic states are positively invariant and (3) the function commutes (in the Weyl/Besicovitch sense) with the shift operator.

In this paper, we obtain a criterion for the decomposition of the @l-fold balanced complete bipartite multigraph @lK"n","n into (not necessarily isomorphic) multistars with the same number of edges. We also give a necessary and sufficient condition of decomposing 2K"n","n into isomorphic multistars.

In this paper, we propose a new way to carry out fitness evaluation in dynamic Particle Swarm Clustering (PSC) with centroid-based encoding. Generally, the PSC fitness function is selected among the clustering validity indices and most of them directly depend on the cluster centroids. In the traditional fitness evaluation approach, the cluster centroids are replaced by the centroids proposed by a particle position. We propose to first compute the centroids of the corresponding clusters and then use these computational centroids in fitness evaluation. The proposed way is called Fitness Evaluation with Computational Centroids (FECC). We conducted an extensive set of comparative evaluations and the results show that FECC leads to a clear improvement in clustering results compared to the traditional fitness evaluation approach with most of the fitness functions considered in this study. The proposed approach was found especially beneficial when underclustering is a problem. Furthermore, we evaluated 31 fitness functions based on 17 clustering validity indices using two PSC methods over a large number of synthetic and real data sets with varying properties. We used three different performance criteria to evaluate the clustering quality and found out that the top three fitness functions are Xu index, WB index, and Dunn variant DU 23 applied using FECC. These fitness functions consistently performed well for both PSC methods, for all data distributions, and according to all performance criteria. In all test cases, they were clearly among the better half of the fitness functions and, in the majority of the cases, they were among the top 4 functions. Further guidance for improved fitness function selection in different situations is provided in the paper.

We give a competitive algorithm to identify all d defective edges in a hypergraph with d unknown. Damaschke did the d=1 case for 2-graphs, Triesch extended the d=1 case to r-graphs, and Johann did the general d case for 2-graphs. So ours is the first attempt to solve the searching for defective edges problem in its full generality. Further, all the above three papers assumed d known. We give a competitive algorithm where d is unknown.

We consider the rational approximation of a perturbed exponential function (1)f(z)=u"0(z)+u"1(z)e^z on the negative real axis R"- with u"0 and u"[email protected]?0 being rational functions. Building upon results from the solution of the ' 1/9'-problem by Gonchar and Rakhmanov, it is shown that rational best approximants to f share the fast asymptotic convergence of rational approximants to the exponential function, despite the fact that the functions (1) may differ substantially from the exponential. Our main result is that for [email protected]?Z fixed, we have (2)limn->[email protected]?f-rn,n+k*@?R"-1/n=19.28902549...=H with H being the same Halphen constant as that already known from the solution of the ' 1/9'-problem and r"n"m^*=r"n"m^*(f,R"-;@?) being a rational best approximant with denominator and numerator degrees at most n and m in the uniform norm on R"- to the function f of type (1). Further, it is shown that the convergence on R"-, which is characterized by (2), extends to compact subsets of the complex plane C and also to Hankel contours in [email protected]?R"-, and this extension holds with the same asymptotic rate of convergence H. Many of the results for rational best approximants extend also to rational close-to-best approximants, which by our definition are rational approximants with a convergence behavior on R"- that is comparable in an nth root sense to that of the best approximants r"n","n^*. The asymptotic distribution of the poles of approximants is studied and determined. In the present paper we present only results, complete proofs are not given, however, some of the main ideas of the proofs are sketched.

The developments in nonlinear dynamics and the theory of chaos have considerably altered our perception and analysis of many complex systems, including the brain. This paper reviews the physical and dynamical aspect of brain's electrical activity from this new perspective and indicates possible future directions. The importance of emerging trends of nonlinear dynamics and chaos to neurobiology has been discussed in the context of various states of consciousness and behaviour. In the past, EEG analysis has been confined to descriptive stochastic statistics and any understanding of the transitional process of brain activities was either nonexistent or not amenable for investigation. With the developments in nonlinear dynamics, the chaotic dynamical parameters and trajectory behaviour will find their use as feature detection techniques in EEG. Furthermore, nonlinear dynamics provides a model for EEG generation and temporal prediction which will help in determining the nature of neuronal processes governing various states of brain activity. The formalism of globally coupled dynamic systems will find applications in modelling the transitional states of EEG.

In this paper we present a new linear algorithm for finding the biconnected components of an undirected simple graph. The presentation of this algorithm is done as an exercise in the use of modern principles and techniques for systematic development of algorithms.

Let M be a matroid with rank function r, and let e@?E(M). The deletion-contraction polymatroid with rank function f=r"M"@?"e+r"M"/"e will be denoted P"e(M). Notice that P"e(M) is uniquely determined by M and e. Similarly, a deletion-contraction polymatroid determines M, unless e is a loop or co-loop. This paper will characterize all polymatroids of this deletion-contraction form by giving the set of excluded minors. Vertigan conjectured that the class of GF(q)-representable deletion-contraction polymatroids is well-quasi-ordered. From this attractive conjecture, both Rota's Conjecture and the WQO Conjecture for GF(q)-representable matroids would follow.

The aim of the paper is to compare the rates of iteration convergence of two staggered numerical schemes: one using successive substitutions and the other the Newton method. In the case of very weakly coupled problems the Newton method is one order faster, but there are specific cases when it is slower than the standard staggered algorithm. In both cases a convergence condition must be verified. The behaviour of the investigated staggered procedures in case of thermo-hydro-mechanical problems are shown on examples.

In last years several assessment methodologies were applied to evaluate the risks connected manufacturing and maintenance practices. The law and the best practices in industry are growing up in importance and relevance. Many times the assessment is related only to the expert opinion. This paper deals with the presentation of a new assessment method, adaptable also to a specific risk such as the mechanical one, using as assessment tools the check-lists and the Petri Nets. Moreover, a real case with the safety analysis for a machine in a carpentry factory is presented, to appraise the effectiveness of the method presented.

Multi-dimensional screening models have many potential applications but economists have so far been hindered by the considerable technical difficulties involved in their resolution. This paper studies the simplest formulation of the general screening model, and we provide a complete solution to this case. We then show how this model can be applied to multi-product nonlinear pricing and to multi-product monopoly regulation. Finally, we discuss how the model has been applied to other economic situations of interest, including auction design and optimal taxation.

In this paper, (d+1)-pencil lattices on simplicial partitions in Rd are studied. The barycentric approach naturally extends the lattice from a simplex to a simplicial partition, providing a continuous piecewise polynomial interpolant over the extended lattice. The number of degrees of freedom is equal to the number of vertices of the simplicial partition. The constructive proof of this fact leads to an efficient computer algorithm for the design of a lattice.

In this paper, we have presented results on silicon thin films deposited by hot-wire CVD at low substrate temperatures (200 °C). Films ranging from amorphous to nanocrystalline were obtained by varying the filament temperature from 1500 to 1800 °C. A crystalline fraction of 50% was obtained for the sample deposited at 1700 °C. The results obtained seemed to indicate that atomic hydrogen plays a leading role in the obtaining of nanocrystalline silicon. The optoelectronic properties of the amorphous material obtained in these conditions are slightly poorer than the ones observed in device-grade films grown by plasma-enhanced CVD due to a higher hydrogen incorporation (13%).

In this paper we present an efficient, accurate and parallelizable direct method for the solution of the (indefinite) linear algebraic systems that arise in the solution of fourth-order partial differential equations (PDEs) using mixed finite element approximations. The method is intended particularly for use when multiple right-hand sides occur, and when high accuracy is required in these solutions.\ud \ud The algorithm is described in some detail and its performance is illustrated through the numerical solution of a biharmonic eigenvalue problem where the smallest eigenpair is approximated using inverse iteration after discretization via the Ciarlet–Raviart mixed finite element method.

In this paper we present a method for reconstructing Fresnel holograms using two liquid crystal devices, one to display the amplitude information and the other to display the phase. The theoretical approach has been adapted to real configurations of VGA panels removed from a commercial video projector. The optical setup is based on the projection of the phase plane into the amplitude plane by means of an imaging lens. Simulated and experimental results are presented.

l -Cystine is the natural least soluble of the naturally occurring amino acids. Its solubility is a function of the hydrogen ion concentration depending on its protonation. This paper presents an investigation on properties of l- cystine in a constant ionic medium of NaCl at different concentrations (3.00, 2.00, 1.00, 0.500, 0.150 mol dm −3 ) and at 25 °C. In such experimental conditions, solubility and its changes as a function of hydrogen ion concentration were determined. Protonation of cystine was studied in acid and basic solution, by measuring the electromotive force of galvanic cell involving a glass electrode. Four protonation constants for l -cystine were determined in all the selected concentrations of ionic medium. The different values obtained for the constants in ionic medium of different concentration could be explained both with the variation of activity coefficients or with the complex formation between l -cystine and sodium ions. Variations of solubility for different concentration of NaCl were observed as well.

In this paper we present a different approach on Dickson and Waters [Astin Bulletin 21 (1991) 199] and De Vylder and Goovaerts [Insurance: Mathematics and Economics 7 (1988) 1] methods to approximate time to ruin probabilities. By means of Markov chain application we focus on the direct calculation of the distribution of time to ruin, and we find that the above recursions appear to be less efficient, although giving the same approximation figures. We show some graphs of the time to ruin distribution for some examples, comparing the different shapes of the densities for different values of the initial surplus. Furthermore, we consider the presence of an upper absorbing barrier and apply the proposed recursion to find ruin probabilities in this case.. info:eu-repo/semantics/publishedVersion

The clinical diagnosis of many dermatological conditions suffers from inadequacies and a histopathological analysis of skin biopsies remains the standard for confirmation of a diagnosis. We suggest that near-infrared (IR) spectroscopy may be a suitable non-invasive, objective tool for characterizing skin conditions. This paper will highlight our in vivo near-IR spectroscopic characterization of skin tumors presented for differential diagnosis of skin cancer. In vivo visible and near-IR spectra (400–2500 nm) were collected from actinic keratoses, basal cell carcinomata, benign nevi, dysplastic nevi, actinic lentigines and seborrheic keratoses by placing a fiber optic probe on the skin. Linear discriminant analysis (LDA) was used to determine whether spectra could be classified according to lesion type and resulted in accuracies of 70–98% in differentiating benign from pre-malignant or malignant lesions. Near-IR spectroscopy is a promising non-invasive technique for the screening of skin lesions., Shedding New Light on Disease: Optical Diagnostics for the New Millennium, June 25-30, 2000, Winnipeg, Canada

This paper re-examines earlier estimates of regional redistribution and stabilization through the central government budget in the US, and produces new estimates of this redistribution and stabilization in the US, Canada, France and the UK. The new estimates rest on panel data econometrics and an adherence to certain accounting principles that have occasionally been violated in the past. As a result of the accounting, the peak estimates for the US and Canada in the earlier literature are never attained. Regional stabilization of personal income through the central government budget emerges as close to 20% in the US, France and the UK, but only 10 to 14% in Canada. In case of gross product instead of personal income accounting, regional stabilization is closer to 10% in the US. As regards France and the UK, the use of panel data econometrics proves essential.

Signal Processing, Vol. 83, nº 11 The initial condition problem for fractional linear system initialisation is studied in this paper. It is based on the generalised initial value theorem. The new approach involves functions belonging to the space of Laplace transformable distributions verifying the Watson–Doetsch lemma. The fractional derivatives of these functions are independent of the derivative de,nition. This class includes the most important functions appearing in computing the Impulse Response of continuous-time fractional linear systems.

Does wealth matter for labor market transitions? This paper aims at giving a quantitative answer to this question. Econometric reduced-form estimates on French panel data provide evidence of a significant wealth effect on the extensive margin of labor supply. Both unemployment duration and job quits rise with holdings of short-term liquid assets. This evidence gives support to the recent development of quantitative dynamic equilibrium search models incorporating precautionary savings. We consider such a model calibrated on French data and focus on the role of the option value of search and the disutility of working. In addition, we pay attention to the important interaction between the intensive and the extensive margins of labor supply. (Copyright: Elsevier)

This paper describes the Cartesian cut cell method, which provides a flexible and efficient alternative to traditional boundary fitted grid methods. The Cartesian cut cell approach uses a background Cartesian grid for the majority of the flow domain with special treatments being applied to cells which are cut by solid bodies, thus retaining a boundary conforming grid. The development of the method is described with applications to problems involving both moving bodies and moving material interfaces.

Countries with significantly different development levels experience similar regulatory transformations in the telecommunications industry. While these changes may be particularly successful in lowering costs, they may also lead to lower consumer welfare in markets in which consumers are highly sensitive to price changes. This paper assessed whether price elasticities for telecommunications demand differ between broad groups of countries according to their development levels. We provided empirical evidence of differences in estimated demand elasticities between developed and less developed countries. Our results suggest that consumers in poorer countries may experience greater welfare losses when incentive regulations are implemented., Fundação para a Ciência e Tecnologia.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2014-02-26T17:16:52Z No. of bitstreams: 1 WOS000185398300016.pdf: 146093 bytes, checksum: 59ba11895ceacd4048e8fbc82eb07511 (MD5) Made available in DSpace on 2014-02-26T17:16:52Z (GMT). No. of bitstreams: 1 WOS000185398300016.pdf: 146093 bytes, checksum: 59ba11895ceacd4048e8fbc82eb07511 (MD5) Previous issue date: 2003-09-15 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:23:29Z No. of bitstreams: 1 WOS000185398300016.pdf: 146093 bytes, checksum: 59ba11895ceacd4048e8fbc82eb07511 (MD5) Made available in DSpace on 2014-05-20T13:23:29Z (GMT). No. of bitstreams: 1 WOS000185398300016.pdf: 146093 bytes, checksum: 59ba11895ceacd4048e8fbc82eb07511 (MD5) Previous issue date: 2003-09-15 This paper deals with a stochastic stability concept for discrete-time Markovian jump linear systems. The random jump parameter is associated to changes between the system operation modes due to failures or repairs, which can be well described by an underlying finite-state Markov chain. In the model studied, a fixed number of failures or repairs is allowed, after which, the system is brought to a halt for maintenance or for replacement. The usual concepts of stochastic stability are related to pure infinite horizon problems, and are not appropriate in this scenario. A new stability concept is introduced, named stochastic tau-stability that is tailored to the present setting. Necessary and sufficient conditions to ensure the stochastic tau-stability are provided, and the almost sure stability concept associated with this class of processes is also addressed. The paper also develops equivalences among second order concepts that parallels the results for infinite horizon problems. (C) 2003 Elsevier B.V. All rights reserved. Univ Estadual Campinas, UNICAMP, Fac Elect Engn, Dept Telemat, BR-13081970 Campinas, SP, Brazil Univ Estadual Paulista, UNESP, Fac Ciências & Tecnol, Dept Matemat, BR-19060400 Pres Prudente, SP, Brazil Univ Estadual Paulista, UNESP, Fac Ciências & Tecnol, Dept Matemat, BR-19060400 Pres Prudente, SP, Brazil

A selected ion flow tube was used to investigate the positive ion chemistry of thiophosphoryl chloride, PSCl\(_3\). Rate coefficients and ion product branching ratios have been determined at room temperature for reactions with nineteen cations ; H\(_3\)O\(^+\), CF\(_3^+\), CF\(^+\), NO\(^+\), NO\(_2^+\), SF\(_2^+\), SF\(^+\), CF\(_2^+\), O\(_2^+\), H\(_2\)O\(^+\), N\(_2\)O\(^+\), O\(^+\), CO\(_2^+\), CO\(^+\), N\(^+\), N\(_2^+\), Ar\(^+\), F\(^+\) and Ne\(^+\) (in order of increasing recombination energy). Complementary data described in the previous paper have been obtained for this molecule via the observation of threshold photoelectron photoion coincidences. For ions whose recombination energies are in the range 10-22 eV, comparisons are made between the product ion branching rations of PSCl\(_3\) from photoionisation and from ion-molecule reactions. In most instances, the data from the two experiments are well correlated, suggesting that long-range charge transfer is the dominant mechanism for these ion-molecule reactions ; the agreement is particularly good for the atomic ions Ar\(^+\), F\(^+\) and Ne\(^+\). Some reactions (e.g. O\(_2^+\) + PSCl\(_3\)), however, exhibit significant differences; short-range charge transfer must then be occurring following the formation of an ion-molecule complex. For ions whose recombination energies are less than 10 eV (i.e. H\(_3\)O\(^+\), CF\(_3^+\), CF\(^+\) and NO\(^+\)), reactions can only occur via a chemical process in which bonds are broken and formed, because the recombination energy of the cation is less than the ionisation energy of PSCl\(_3\).

In this paper, the influence of the deposition conditions on the performance of p–i–n microcrystalline silicon solar cells completely deposited by hot-wire chemical vapor deposition is studied. With this aim, the role of the doping concentration, the substrate temperature of the p-type layer and of amorphous silicon buffer layers between the p/i and i/n microcrystalline layers is investigated. Best results are found when the p-type layer is deposited at a substrate temperature of 125 °C. The dependence seen of the cell performance on the thickness of the i layer evidenced that the efficiency of our devices is still limited by the recombination within this layer, which is probably due to the charge of donor centers most likely related to oxygen.

Under the Kyoto Protocol industrialized countries will be able to meet carbon emission reduction commitments by financing forestry projects that sequester carbon in developing countries. While this mechanism would compensate for missing markets in forest environmental services, it could also enable industrialized countries to avoid reducing energy use. This paper assesses whether such projects could contribute to improved logging practices in the tropics. Results from studies primarily in Asia and Latin America are analyzed in the context of the modalities of the Kyoto Protocol. Results show that the opportunity cost of shifting from conventional logging to improved practices may have been underestimated. At the same time the long-term carbon and biodiversity benefits of improved forest management may have been underestimated. These results follow primarily from the fact that most previous studies assume that a permanent forest estate is maintained under conventional logging and that cutting cycles are as long as 30–60 years. A more realistic scenario, however, consists of repeated harvesting at short intervals during the first few decades, resulting in the degradation of the forest into shrub and grassland. The implications of these results are that forest management projects may be less cost-effective than previously assumed. Therefore, expectations about their potential contribution to improved management should be scaled down. At the same time, the extent to which such projects will enable industrialized countries to avoid reducing industrial pollution is also unlikely to be significant. Cost-effectiveness is likely to be highest where timber volumes in the first few decades after initial logging are comparable under conventional and improved logging. This is likely where topography is relatively flat, biodiversity values are low, wastage of felled timber is high and the policy environment is favorable. A number of proactive measures are suggested to expand the niche for forest management carbon projects. These measures are justified because the incremental carbon and biodiversity benefits in the long run may be higher than previous studies have indicated.

Countries emerging from civil war attract both aid and policy advice. This paper provides the first systematic empirical analysis of aid and policy reform in the post-conflict growth process. It is based on a comprehensive data set of large civil wars and covers 27 countries that were in their first decade of post-conflict economic recovery during the 1990s. Collier and Hoeffler first investigate whether the absorptive capacity for aid is systematically different in post-conflict countries. They find that during the first three post-conflict years, absorptive capacity is no greater than normal, but that in the rest of the first decade it is approximately double its normal level. So ideally, aid should phase in during the decade. Historically, aid has not, on average, been higher in post-conflict societies, and it has tended to taper out over the course of the decade. The authors then investigate whether the contribution of policy to growth is systematically different in post-conflict countries, and in particular, whether particular components of policy are differentially important. For this they use the World Bank policy rating database. The authors find that growth is more sensitive to policy in post-conflict societies. Comparing the efficacy of different policies, they find that social policies are differentially important relative to macroeconomic policies. However, historically, this does not appear to have been how policy reform has been prioritized in post-conflict societies. This paper--a product of the Development Research Group--is part of a larger effort in the group to study the economics of conflict.

In this paper a comparison among several micromechanical contact models is presented. The aim of the research is to provide a degree of confidence about the differences between the predictions of the contact behavior provided by the models. For this purpose some ideal microscopically rough surfaces with self-affine topography have been generated by means of a numerical algorithm. From such surfaces all the parameters needed to characterize them from the statistical viewpoint have been extracted. The predictions provided by the models with increasing normal load for the evolution of the real contact area, the number of contact points and other useful parameters have been outlined with diagrams, clearly showing the existing differences.

In this paper we present error and performance analysis of a Monte Carlo variance reduction method for solving multidimensional integrals and integral equations. This method, called importance separa- tion, combines the idea of separation of the domain into uniformly small subdomains with the approach of importance sampling. The importance separation method is originally described in our previous works, here we generalize our results and discuss the performance in comparison with crude Monte Carlo and importance sampling. Based on our previous in- vestigation we propose efficient parallelizations of the importance sepa- ration method. Numerical tests implemented on PowerPC cluster using MPI are provided. The considered algorithms are carried out using pseu- dorandom numbers.

This paper focuses on analysing tillage as a mechanism for the transformation of soil spatial variability, soil morphology, superficial soil properties and development of soil–landscape relationships in agricultural lands. A new theoretical two-dimensional model of soil catena evolution due to soil redistribution by tillage is presented. Soil profile truncation occurs through loss of soil mass on convexities and in the upper areas of the cultivated hillslopes; while the opposite effect takes place in concavities and the lower areas of the field where the original soil profile becomes buried. At sectors of rectilinear morphology in the hillslope (backslope positions), a null balance of soil translocation takes place, independent of the slope gradient and of the rate of downslope soil translocation. As a result, in those backslope areas, a substitution of soil material in the surface horizon with material coming from upslope areas takes place. This substituted material can produce an inversion of soil horizons in the original soil profile and sometimes, the formation of ‘‘false truncated soil’’. In the Skogstad agricultural field (Cyrus, MN) spatial patterns of soil properties (soil calcium carbonate content) in the surface soil horizons and soil morphology along several slope transects were analyzed. These spatial patterns are compared with those estimated for soil redistribution (areas of erosion and deposition) due to tillage using the Soil Redistribution by Tillage (SORET) model and water erosion using the models Water Erosion Prediction Project (WEPP) and Universal Soil Loss Equation (Usle2D). Results show that tillage was the predominant process of soil redistribution in the studied agricultural field. Finally, some practical implications of the proposed model of soil landscape modification by tillage are discussed. Nomographs to calculated the intensity of the expansion process of the eroded soil units by tillage are proposed for three different patterns of tillage.

This chapter examines empirical strategies that have been or could be used to evaluate the importance of agglomeration and trade models. This theoretical approach, widely known as "New Economic Geography" (NEG), emphasizes the interaction between transport costs and firm-level scale economies as a source of agglomeration. NEG focuses on forward and backward trade linkages as causes of observed spatial concentration of economic activity. We survey the existing literature, organizing the papers we discuss under the rubric of five interesting and testable hypotheses that emerge from NEG theory. We conclude the chapter with an overall assessment of the empirical support for NEG and suggest some directions for future research.

This paper examines forest management and silvicultural practices of small colonist landholders in the western Brazilian Amazon state of Rondonia. Although recent colonists in the Amazon are widely acknowledged as key agents of tropical forest conversion, relatively little is known of their uses of primary and secondary forest patches and the degree to which these farmers plant trees as part of their land use strategies. Based on longitudinal survey data drawn from three different colonist settlements in 1992 and 2002, this paper explores the range of small farmer's uses of forests and fallows that may indicate future trends in forest management. We also examine the links between forest extraction and tree planting and the factors that may influence these practices. We found that nearly 40% of the farmers surveyed regularly extract useful products from their forests. We examine the types and quantities of timber and non-timber forest products extracted by small farmers over this 10-year study period, and reasons given by them for managing or not managing their forest patches. Forest extractor households were characterized as having a smaller percentage of their land deforested and smaller cattle herds. In addition, we found that roughly 30% of the small farmers surveyed planted trees on their farms during this 10-year study period. Results of statistical analysis (ANOVA and chi square contingency tests) to identify factors that correlate with tree planting behavior indicate that tree planters own larger plots, reside longer on those plots, have a larger number of working age household members, and secure land titles. They were also more likely to participate in social organizations. We conclude that despite ongoing deforestation processes in the region, natural forest use is an important subsistence activity for many small farmers and that many farmers are planting and managing tree species for both short-term products and as long-term investments. # 2004 Published by Elsevier B.V.

In this paper, we examined the basic properties in the 1:1 mixture of lithium amide LiNH2 and lithium hydride LiH as a candidate of reversible hydrogen storage materials. The thermal desorption mass spectra of the ball milled mixture without any catalysts indicated that hydrogen H2 is released in the temperature range from 180 to 400 °C while emitting a considerable amount of ammonia NH3. On the other hand, the ball milled mixture containing a small amount of TiCl3 as a catalyst showed the most superior hydrogen storage properties among the 1:1 mixtures with a small amount of catalysts, Ni, Fe, Co metals and TiCl3 (1 mol.%). That is, the product desorbs a large amount of hydrogen (∼5.5 wt.%) in the temperature from 150 to 250 °C under the condition of a heating rate of 5 °C/min, but it does not desorb ammonia at all within our experimental accuracy. In addition, we confirmed that the product shows an excellent cycle retention with an effective hydrogen capacity of more than 5 wt.% and a high reaction rate until at least 3 cycles.

In Gulf countries, most power plants are co-generation power desalting plants (CPDP) that generate electric energy and also produce fresh water through the desalination of seawater. This paper provides detailed technical and economical analyses to evaluate a new generation of dual purpose technology that includes the integration of reverse osmosis (RO) processes with existing thermal desalination processes and power generation (triple hybrid system) at Layyah plant, Sharjah, UAE. Hybridization of sweater reverse osmosis (SWRO) and the multi-stage flash (MSF) technology was considered to improve the performance of latter and reduce the cost of the produced water. Moreover, “idle” power in winter (seasonal surplus of unused power) was mainly utilized by RO to further reduce the cost of the hybrid system for six months of the year. Spinning reserve was also used to further reduce the cost of the proposed hybrid system. Integration ofthe three processes of MSF, MED, and RO desalination technologies could be made at different levels through which the resulting of water cost will depend on the selected configuration and the cost of materials of construction, equipment, membrane, energy, etc. Thus, the capital and annual operating costs were calculated for all potential alternatives for various plant capacities. It was found that for all plant capacities, integrated hybrid systems resulted in most cost effective solution. For example, at a capacity of 50 MIGD, the present worth of the cost was calculated to be 588.7, 443.2, and 380 million US$ for MSF, MED, and hybrid RO systems, respectively.

Textile industries consume large amounts of water and generate highly dye-contaminated effluents. Textile wastewaters have to be treated in order to be recycled in the process or to meet legislative requirements before being discharged. The objective of the present study was to examine the potential use of the vacuum membrane distillation process for the treatment of dyed solutions. Methylene blue (MB) was used as a model dye. Batch experiments were conducted on dilute MB-water mixtures using a tubular polypropylene membrane module. The concentration of MB dye within the feed reservoir was monitored over time. The impact of operating variables such as feed temperature, flow rate and initial dye concentration was investigated. A mathematical model incorporating temperature and concentration polarization effects was developed and validated on the experimental data.

Mining association rules with multiple minimum supports is an important generalization of the association-rule-mining problem, which was recently proposed by Liu et al. Instead of setting a single minimum support threshold for all items, they allow users to specify multiple minimum supports to reflect the natures of the items, and an Apriori-based algorithm, named MSapriori, is developed to mine all frequent itemsets. In this paper, we study the same problem but with two additional improvements. First, we propose a FP-tree-like structure, MIS-tree, to store the crucial information about frequent patterns. Accordingly, an efficient MIS-tree-based algorithm, called the CFP-growth algorithm, is developed for mining all frequent itemsets. Second, since each item can have its own minimum support, it is very difficult for users to set the appropriate thresholds for all items at a time. In practice, users need to tune items' supports and run the mining algorithm repeatedly until a satisfactory end is reached. To speed up this time-consuming tuning process, an efficient algorithm which can maintain the MIS-tree structure without rescanning database is proposed. Experiments on both synthetic and real-life datasets show that our algorithms are much more efficient and scalable than the previous algorithm.

For high voltage (HV) transmission lines (TLs) the backflashover phenomenon can occur when lightning strikes a tower or a shield wire (SW). In this paper, the backflashover phenomenon of typical HV-TLs has been studied. The simulation code, based on ATP/EMTP program, accounts for both the discharge process between the arcing horns of insulator strings, by means of a leader progression model and the non-linear transient behaviour of tower grounding systems consisting of vertical rod(s). The lightning current ranges, causing back flash in a 161 kV-50 Hz single circuit line with two grounded SWs, have been investigated in detail. Numerical results of the investigations are in good agreement with actual behavior of the studied TL.

Throughout 6 yr of operation, the pilot Rheine ZVI CRB has consistently shown constant degradation rates of perchloroethylene (PCE) at rates > 98%, and it is assumed that combined abiotic and biotic effects inside the barrier significantly contribute to this successful performance. Microbial activities at the Rheine PRB for remediation practice and long-term performance of PRB were studied. Microbial activity led to significant consumption of molecular hydrogen, which was produced abiotically through the anaerobic corrosion of zero valent iron. ReSponge™ seemed to be superior to other ZVI types regarding long term degradation efficiency, likely due to its specific characteristics (larger granules, but amorphous with a high internal surface, special composition). Therefore, it provided high dechlorination potential towards the chlorinated contaminants even after 7 yr of operation of the Rheine barrier. Besides the consumption of H2, homo-acetogenic and methanogenic bacteria could help reduce excessive carbonate precipitation by converting dissolved CO2 into acetate and methane, respectively. However, direct biological contribution by means of dechlorination could not be observed. This is an abstract of a paper presented at the proceedings of the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).

The possible use of polyethylene naphthalate as substrate for low-temperature deposited solar cells has been studied in this paper. The transparency of this polymer makes it a candidate to be used in both substrate and superstrate configurations. ZnO:Al has been deposited at room temperature on top of PEN. The resulting structure PEN/ZnO:Al presented good optical and electrical properties. PEN has been successfully textured (nanometer and micrometer random roughness) using hot-embossing lithography. Reflector structures have been built depositing Ag and ZnO:Al on top of the stamped polymer. The deposition of these layers did not affect the final roughness of the whole. The reflector structure has been morphologically and optically analysed to verify its suitability to be used in solar cells.