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Several Alternatives (several + alternative)
Selected AbstractsOn discontinuous Galerkin methodsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8 2003O. C. Zienkiewicz Abstract Discontinuous Galerkin methods have received considerable attention in recent years for problems in which advection and diffusion terms are present. Several alternatives for treating the diffusion and advective fluxes have been introduced. This report summarizes some of the methods that have been proposed. Several numerical examples are included in the paper. These present discontinuous Galerkin solutions of one-dimensional problems with a scalar variable. Results are presented for diffusion,reaction problems and advection,diffusion problems. We discuss the performance of various formulations with respect to accuracy as well as stability of the method. Copyright © 2003 John Wiley & Sons, Ltd. [source] Matching Technologies with Potential End Users: A Knowledge Engineering Approach for Agricultural Research ManagementJOURNAL OF AGRICULTURAL ECONOMICS, Issue 1 2004J. David Reece This paper addresses the problem of priority setting that faces developing country agricultural research, a problem whose relevance has been sharpened by the current context of demands for greater efficiency and targeted impact. A new method for ex ante estimation of the impact of developing each of several alternative proposed technologies is described and illustrated through an example from West Africa. This method is based on the notion of market segmentation, which normally makes intensive use of secondary data-sets that are simply not available for rural areas of developing countries. To circumvent this lack of secondary data, the method adopts a knowledge engineering approach based on the views of an expert panel familiar with the region to be served. Descriptions of proposed technologies are matched with the interests and resources of identified market segments, together with the characteristics of their farming systems and locations, to identify those segments whose members are likely to use the proposed technology. Further development of the method is discussed. [source] CMP wastewater management using the concepts of design for environmentENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2002Gordon C. C. YangArticle first published online: 20 APR 200 Application of design for environment (DfE) concepts to management of wastewater from chemical mechanical polishing (CMP) processes are presented in this paper. Today, DfE is a prevailing concept and is widely adopted by advanced nations in lieu of the traditional "command and control" approach to control waste and toxic emissions. Designing environmentally-benign processes and products is a new and challenging frontier for engineering professionals, including those in the semiconductor industry. An insatiable need for water and subsequent wastewater treatment has imposed a chilling effect on semiconductor industry growth. It was estimated that semiconductor producers consumed more than 5.523 × 108 m3 of water in 2000. Of this amount, CMP processes accounted for 40% of the total. The CMP tool market and CMP slurry market are estimated to have 36% and 29% annual growth rates, respectively between 2000 and 2005. Inevitably, a tremendous amount of waste slurry and post-CMP rinse water will be generated and have to be managed properly. CMP wastewater is characterized by its high content of suspended solids having sub-micron particle sizes, high turbidity, and high conductivity. Traditional wastewater treatment technologies, such as chemical coagulation/precipitation, do not work well for CMP wastewater, because it would generate a large volume of sludge, which might cause disposal problems in many countries, such as Taiwan. Therefore, utilizing pollution prevention principles in the design of CMP tools, development of new CMP slurries, and improved plant operations are necessary to minimize environmental damage. Reclamation of process water is also a common requirement in the semiconductor industry. To this end, several alternatives for source reduction of CMP wastewater and water reclamation are presented in this paper. [source] Design sensor trajectory for control: Application to sheet-forming processesAICHE JOURNAL, Issue 8 2000Der-Ming Chang The conventional scanning sensor generates a zig-zag pattern for the sheet-forming process, immediately leading to the problem of unequal measurement update intervals in state estimation. Instead of reconstructing the profile given a zig-zag pattern, the sensor trajectory was redesigned to better estimation and control. In this work, the characteristics of the conventional scanning sensor were explored as well as the implications in estimation and control. The concept of elliptic sensor contour is presented, deriving analytical expressions for the sensor trajectories. Alternatively, the improved sensor trajectory can be obtained using a variable-speed scanning sensor under linear sweep. That implies that control performance can be improved by reprogramming the motor of the existing sensor. Moreover, several alternatives for sensor arrangement are also explored. The results for estimation and control can be used as guidelines for the development of future sensor technology. [source] Bisexuality: A Contemporary Paradox for WomenJOURNAL OF SOCIAL ISSUES, Issue 2 2000Paula C. Rodríguez Rust The cultural construction of ,lesbian' and ,heterosexual' women in late-nineteenth-century European cultures created both the possibility of conceiving the "bisexual" woman and the belief that bisexuality cannot exist. Social scientists have suggested several alternatives to dichotomous constructions of sexuality to facilitate the conceptualization of, and therefore empirical research on, bisexuality. This article reviews these alternatives and summarizes the current state of researchon bisexuality, including research on ,situational homosexuality' (behavioral bisexuality), recent national probability studies on sexual behaviors and identities in the United States, the meanings of bisexual self-identities among women, masculinist biases in methods of assessing and theorizing sexual self-identities, and prejudice against bisexuals. The article concludes with suggestions for future social scientific research on bisexuality. [source] Analysis of longitudinal data with drop-out: objectives, assumptions and a proposalJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 5 2007Peter Diggle Summary. The problem of analysing longitudinal data that are complicated by possibly informative drop-out has received considerable attention in the statistical literature. Most researchers have concentrated on either methodology or application, but we begin this paper by arguing that more attention could be given to study objectives and to the relevant targets for inference. Next we summarize a variety of approaches that have been suggested for dealing with drop-out. A long-standing concern in this subject area is that all methods require untestable assumptions. We discuss circumstances in which we are willing to make such assumptions and we propose a new and computationally efficient modelling and analysis procedure for these situations. We assume a dynamic linear model for the expected increments of a constructed variable, under which subject-specific random effects follow a martingale process in the absence of drop-out. Informal diagnostic procedures to assess the tenability of the assumption are proposed. The paper is completed by simulations and a comparison of our method and several alternatives in the analysis of data from a trial into the treatment of schizophrenia, in which approximately 50% of recruited subjects dropped out before the final scheduled measurement time. [source] Extending the shelf-life of bananas with 1-methylcyclopropene and a chitosan-based edible coatingJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2009Manuel Baez-Sañudo Abstract BACKGROUND: The marketability of bananas over long distances has been limited due to their highly perishable nature and sensitivity to ethylene. To increase the shelf-life several alternatives have been tested in attempts to maintain quality characteristics. We evaluated the effects of 1-methylcyclopropene (SmartFreshSM, 1-MCP) and a chitosan-based edible coating (FreshSeal®, EC), applied alone or combined, on bananas at ripeness stage 3. All fruits were stored for 8 days at 22 °C, 85% RH. Color development, weight loss, firmness, physiological, sensory and chemical variables were evaluated. RESULTS: After 3 days, control and EC-treated fruits were completely yellow (°Hue = 90), while 1-MCP treated fruits alone and combined with EC were still showing some green colorations on tips and neck of fingers. After 7 days, fruits treated with the combination (EC + 1-MCP) reached a Hue value of 90. Firmer fruits were observed with 1-MCP alone or combined with EC. A decrease of 0.15% titratable acidity and an increase of 8°Brix were observed in all treatments during the experiment. The incidence of sugar spots was delayed and diminished on fruits treated with 1-MCP either alone or combined. Sensory results showed no adverse effects by using the 1-MCP or the edible coating. CONCLUSION: The combined treatment of EC + 1-MCP could be used to extend the commercial life of bananas for up to four more days. Copyright © 2009 Society of Chemical Industry [source] A Dependence Metric for Possibly Nonlinear ProcessesJOURNAL OF TIME SERIES ANALYSIS, Issue 5 2004C. W. Granger Abstract., A transformed metric entropy measure of dependence is studied which satisfies many desirable properties, including being a proper measure of distance. It is capable of good performance in identifying dependence even in possibly nonlinear time series, and is applicable for both continuous and discrete variables. A nonparametric kernel density implementation is considered here for many stylized models including linear and nonlinear MA, AR, GARCH, integrated series and chaotic dynamics. A related permutation test of independence is proposed and compared with several alternatives. [source] Normative Conflicts and The Logic of ,Ought'NOUS, Issue 3 2009Lou Goble On the face of it, normative conflicts are commonplace. Yet standard deontic logic declares them to be logically impossible. That prompts the question, What are the proper principles of normative reasoning if such conflicts are possible? This paper examines several alternatives that have been proposed for a logic of ,ought' that can accommodate normative conflicts, and finds all of them unsatisfactory as measured against three criteria of adequacy. It then introduces a new logic that does meet all three criteria, and so allows for the possibility of genuine normative conflicts. [source] Estimation of regression parameters in missing data problemsTHE CANADIAN JOURNAL OF STATISTICS, Issue 2 2006Donald L. Mcleish Abstract Let Y be a response variable, possibly multivariate, with a density function f (y|x, v; ,) conditional on vectors x and v of covariates and a vector , of unknown parameters. The authors consider the problem of estimating , when the values taken by the covariate vector v are available for all observations while some of those taken by the covariate x are missing at random. They compare the profile estimator to several alternatives, both in terms of bias and standard deviation, when the response and covariates are discrete or continuous. Estimation des paramètres de régression en I'absence de certaines données Soit Y une variable réponse uni- ou multi-dimensionnelle et soit f(y|x, v; ,) sa densité étant donné des vecteurs x et v de covariables et un vecteur , de paramètres inconnus. Les auteurs s'intéressent à l'estimation de , lorsque la valeur de v est disponible pour toutes les observations, mais que certaines valeurs de x sont manquantes au hasard. Us comparent l'estimateur profil à diverses autres solutions, tant en terme de biais que d'écart-type, selon que la variable réponse et les covariables sont discrètes ou continues. [source] An extended Escherichia coli "Selenocysteine Insertion Sequence" (SECIS) as a multifunctional RNA structureBIOFACTORS, Issue 1-4 2001Hanna Engelberg-Kulka Abstract The genetic code, once thought to be rigid, has been found to permit several alternatives in its reading. Interesting alternative relates to the function of the UGA codon. Usually, it acts as a stop codon, but it can also direct the incorporation of the amino acid selenocysteine into a polypeptide. UGA-directed selenocysteine incorporation requires a cis-acting mRNA element called the "selenocysteine insertion sequence" (SECIS) that can form a stem-loop RNA structure. Here we discuss our investigation on the E. coli SECIS. This includes the follows: 1) The nature of the minimal E. coli SECIS. We found that in E. coli only the upper-stem and loop of 17 nucleotides of the SECIS is necessary for selenocysteine incorporation on the condition that it is located in the proper distance from the UGA [34]; 2) The upper stem and loop structure carries a bulged U residue that is required for selenocysteine incorporation [34] because of its interaction with SelB; and 3) We described an extended fdhF SECIS that includes the information for an additional function: The prevention of UGA readthrough under conditions of selenium deficiency [35]. This information is contained in a short mRNA region consisting of a single C residue adjacent to the UGA on its downstream side, and an additional segment consisting of the six nucleotides immediately upstream from it. These two regions act independently and additively and probably through different mechanisms. The single C residue acts as itself; the upstream region acts at the level of the two amino acids, arginine and valine, for which it codes. These two codons at the 5, side of the UGA correspond to the ribosomal E and P sites. Finally, we present a model for the E. coli fdhF SECIS as a multifunctional RNA structure containing three functional elements. Depending on the availability of selenium the SECIS enables one of two alternatives for the translational machinery: Either selenocysteine incorporation into a polypeptide or termination of the polypeptide chain. [source] | ||||||||||||||||