Home About us Contact
|
Home About us Contact | ||
|
|
||
Search Techniques (search + techniques)
Selected AbstractsFlexible flow shop scheduling: optimum, heuristics and artificial intelligence solutionsEXPERT SYSTEMS, Issue 2 2005Hong Wang Abstract: For the past three decades or so the flexible flow shop (FFS) scheduling problem has attracted many researchers. Numerous research articles have been published on this topic. This study reviews research on the FFS scheduling problem from the past and the present. The solution approaches reviewed range from the optimum to heuristics and to artificial intelligence search techniques. I not only discuss the details from the selected methods and compare them, but also provide insights and suggestions for future research. [source] A BEM-based genetic algorithm for identification of polarization curves in cathodic protection systemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 2 2002Panayiotis Miltiadou Abstract The purpose of this work is to apply an inverse boundary element formulation in order to develop efficient algorithms for identification of polarization curves in a cathodic protection system. The problem is to minimize an objective function measuring the difference between observed and BEM-predicted surface potentials. The numerical formulation is based on the application of genetic algorithms, which are robust search techniques emulating the natural process of evolution as a means of progressing towards an optimum solution. Examples of application are included in the paper for different types of polarization curves in finite and infinite electrolytes. The accuracy and efficiency of the numerical results are verified by comparison with standard conjugate gradient techniques. As a result of this research, the genetic algorithm approach is shown to be more robust, independent of the position of the sensors and of initial guesses, and will be further developed for three-dimensional applications. Copyright © 2002 John Wiley & Sons, Ltd. [source] Nursing and midwifery management of hypoglycaemia in healthy term neonatesINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 7 2005Vivien Hewitt BSc(Hons) GradDipLib Executive summary Objectives The primary objective of this review was to determine the best available evidence for maintenance of euglycaemia, in healthy term neonates, and the management of asymptomatic hypoglycaemia in otherwise healthy term neonates. Inclusion criteria Types of studies The review included any relevant published or unpublished studies undertaken between 1995 and 2004. Studies that focus on the diagnostic accuracy of point-of-care devices for blood glucose screening and/or monitoring in the neonate were initially included as a subgroup of this review. However, the technical nature and complexity of the statistical information published in diagnostic studies retrieved during the literature search stage, as well as the considerable volume of published research in this area, suggested that it would be more feasible to analyse diagnostic studies in a separate systematic review. Types of participants The review focused on studies that included healthy term (37- to 42-week gestation) appropriate size for gestational age neonates in the first 72 h after birth. Exclusions ,,preterm or small for gestational age newborns; ,,term neonates with a diagnosed medical or surgical condition, congenital or otherwise; ,,babies of diabetic mothers; ,,neonates with symptomatic hypoglycaemia; ,,large for gestational age neonates (as significant proportion are of diabetic mothers). Types of intervention All interventions that fell within the scope of practice of a midwife/nurse were included: ,,type (breast or breast milk substitutes), amount and/or timing of feeds, for example, initiation of feeding, and frequency; ,,regulation of body temperature; ,,monitoring (including screening) of neonates, including blood or plasma glucose levels and signs and symptoms of hypoglycaemia. Interventions that required initiation by a medical practitioner were excluded from the review. Types of outcome measures Outcomes that were of interest included: ,,occurrence of hypoglycaemia; ,,re-establishment and maintenance of blood or plasma glucose levels at or above set threshold (as defined by the particular study); ,,successful breast-feeding; ,,developmental outcomes. Types of research designs The review initially focused on randomised controlled trials reported from 1995 to 2004. Insufficient randomised controlled trials were identified and the review was expanded to include additional cohort and cross-sectional studies for possible inclusion in a narrative summary. Search strategy The major electronic databases, including MEDLINE/PubMed, CINAHL, EMBASE, LILACS, Cochrane Library, etc., were searched using accepted search techniques to identify relevant published and unpublished studies undertaken between 1995 and 2004. Efforts were made to locate any relevant unpublished materials, such as conference papers, research reports and dissertations. Printed journals were hand-searched and reference lists checked for potentially useful research. The year 1995 was selected as the starting point in order to identify any research that had not been included in the World Health Organisation review, which covered literature published up to 1996. The search was not limited to English language studies. Assessment of quality Three primary reviewers conducted the review assisted by a review panel. The review panel was comprised of nine nurses with expertise in neonatal care drawn from senior staff in several metropolitan neonatal units and education programs. Authorship of journal articles was not concealed from the reviewers. Methodological quality of each study that met the inclusion criteria was assessed by two reviewers, using a quality assessment checklist developed for the review. Disagreements between reviewers were resolved through discussion or with the assistance of a third reviewer. Data extraction and analysis Two reviewers used a data extraction form to independently extract data relating to the study design, setting and participants; study focus and intervention(s); and measurements and outcomes. As only one relevant randomised controlled trial was found, a meta-analysis could not be conducted nor tables constructed to illustrate comparisons between studies. Instead, the findings were summarised by a narrative identifying any relevant findings that emerged from the data. Results Seven studies met the inclusion criteria for the objective of this systematic review. The review provided information on the effectiveness of three categories of intervention , type of feeds, timing of feeds and thermoregulation on two of the outcome measures identified in the review protocol , prevention of hypoglycaemia, and re-establishment and maintenance of blood or plasma glucose levels above the set threshold (as determined by the particular study). There was no evidence available on which to base conclusions for effectiveness of monitoring or developmental outcomes, and insufficient evidence for breast-feeding success. Given that only a narrative review was possible, the findings of this review should be interpreted with caution. The findings suggest that the incidence of hypoglycaemia in healthy, breast-fed term infants of appropriate size for gestational age is uncommon and routine screening of these infants is not indicated. The method and timing of early feeding has little or no influence on the neonatal blood glucose measurement at 1 h in normal term babies. In healthy, breast-fed term infants the initiation and timing of feeds in the first 6 h of life has no significant influence on plasma glucose levels. The colostrum of primiparous mothers provides sufficient nutrition for the infant in the first 24 h after birth, and supplemental feeds or extra water is unnecessary. Skin-to-skin contact appears to provide an optimal environment for fetal to neonatal adaptation after birth and can help to maintain body temperature and adequate blood glucose levels in healthy term newborn infants, as well as providing an ideal opportunity to establish early bonding behaviours. Implications for practice The seven studies analysed in this review confirm the World Health Organisation's first three recommendations for prevention and management of asymptomatic hypoglycaemia, namely: 1Early and exclusive breast-feeding is safe to meet the nutritional needs of healthy term newborns worldwide. 2Healthy term newborns that are breast-fed on demand need not have their blood glucose routinely checked and need no supplementary foods or fluids. 3Healthy term newborns do not develop ,symptomatic' hypoglycaemia as a result of simple underfeeding. If an infant develops signs suggesting hypoglycaemia, look for an underlying condition. Detection and treatment of the cause are as important as correction of the blood glucose level. If there are any concerns that the newborn infant might be hypoglycaemic it should be given another feed. Given the importance of thermoregulation, skin-to-skin contact should be promoted and ,kangaroo care' encouraged in the first 24 h after birth. While it is important to main the infant's body temperature care should be taken to ensure that the child does not become overheated. [source] Learning cooperative linguistic fuzzy rules using the best,worst ant system algorithmINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 4 2005Jorge Casillas Within the field of linguistic fuzzy modeling with fuzzy rule-based systems, the automatic derivation of the linguistic fuzzy rules from numerical data is an important task. In the last few years, a large number of contributions based on techniques such as neural networks and genetic algorithms have been proposed to face this problem. In this article, we introduce a novel approach to the fuzzy rule learning problem with ant colony optimization (ACO) algorithms. To do so, this learning task is formulated as a combinatorial optimization problem. Our learning process is based on the COR methodology proposed in previous works, which provides a search space that allows us to obtain fuzzy models with a good interpretability,accuracy trade-off. A specific ACO-based algorithm, the Best,Worst Ant System, is used for this purpose due to the good performance shown when solving other optimization problems. We analyze the behavior of the proposed method and compare it to other learning methods and search techniques when solving two real-world applications. The obtained results lead us to remark the good performance of our proposal in terms of interpretability, accuracy, and efficiency. © 2005 Wiley Periodicals, Inc. Int J Int Syst 20: 433,452, 2005. [source] Efficient optimization strategies with constraint programming,AICHE JOURNAL, Issue 2 2010Prakash R. Kotecha Abstract In this article, we propose novel strategies for the efficient determination of multiple solutions for a single objective, as well as globally optimal pareto fronts for multiobjective, optimization problems using Constraint Programming (CP). In particular, we propose strategies to determine, (i) all the multiple (globally) optimal solutions of a single objective optimization problem, (ii) K -best feasible solutions of a single objective optimization problem, and (iii) globally optimal pareto fronts (including nonconvex pareto fronts) along with their multiple realizations for multiobjective optimization problems. It is shown here that the proposed strategy for determining K -best feasible solutions can be tuned as per the requirement of the user to determine either K -best distinct or nondistinct solutions. Similarly, the strategy for determining globally optimal pareto fronts can also be modified as per the requirement of the user to determine either only the distinct set of pareto points or determine the pareto points along with all their multiple realizations. All the proposed techniques involve appropriately modifying the search techniques and are shown to be computationally efficient in terms of not requiring successive re-solving of the problem to obtain the required solutions. This work therefore convincingly addresses the issue of efficiently determining globally optimal pareto fronts; in addition, it also guarantees the determination of all the possible realizations associated with each pareto point. The uncovering of such solutions can greatly aid the designer in making informed decisions. The proposed approaches are demonstrated via two case studies, which are nonlinear, combinatorial optimization problems, taken from the area of sensor network design. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] On the development of name search techniques for ArabicJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 6 2006Syed Uzair Aqeel The need for effective identity matching systems has led to extensive research in the area of name search. For the most part, such work has been limited to English and other Latin-based languages. Consequently, algorithms such as Soundex and n -gram matching are of limited utility for languages such as Arabic, which has vastly different morphologic features that rely heavily on phonetic information. The dearth of work in this field is partly caused by the lack of standardized test data. Consequently, we have built a collection of 7,939 Arabic names, along with 50 training queries and 111 test queries. We use this collection to evaluate a variety of algorithms, including a derivative of Soundex tailored to Arabic (ASOUNDEX), measuring effectiveness by using standard information retrieval measures. Our results show an improvement of 70% over existing approaches. [source] Purification, crystallization, X-ray diffraction analysis and phasing of a Fab fragment of monoclonal neuroantibody ,D11 against nerve growth factorACTA CRYSTALLOGRAPHICA SECTION D, Issue 7 2004Sonia Covaceuszach The rat monoclonal neuroantibody ,D11 is a potent antagonist that prevents the binding of nerve growth factor (NGF) to its tyrosine kinase A receptor (TrkA) in a variety of systems, most notably in two in vivo systems linked to crucial pathological states, such as Alzheimer's disease and HIV infection. To provide further insights into the mechanism of action of this potentially therapeutic monoclonal antibody, structural studies of the antigen-binding fragment (Fab) of ,D11 were performed. ,D11 IgG2a immunoglobulin was obtained from hybridomas by in vitro tissue culture. The ,D11 Fab crystallizes in two crystal forms. Form I belongs to space group P1, with unit-cell parameters a = 42.7, b = 50.6, c = 102.7,Å, , = 82.0, , = 89.1, , = 86.0°. With two molecules in the asymmetric unit, VM is 2.3,Å3,Da,1 and the solvent content is 46%. A complete data set has been collected at 2.7,Å resolution on beamline XRD-1 (ELETTRA, Trieste, Italy). Form II belongs to space group C2, with unit-cell parameters a = 114.8, b = 69.4, c = 64.10,Å, , = 117.0°. With one molecule in the asymmetric unit, VM is 2.4,Å3,Da,1 and the solvent content is 48%. A complete data set has been collected at 1.7,Å resolution on beamline ID14-1 (ESRF, Grenoble, France). Phasing was successfully performed by Patterson search techniques and refinement of the structures is currently under way. Crystal forms I and II display a close-packing pattern. [source] Crystallization, X-ray diffraction analysis and phasing of 17,-hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatusACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 12 2005Alberto Cassetta 17,-Hydroxysteroid dehydrogenase from the filamentous fungus Cochliobolus lunatus (17,-HSDcl) is an NADP(H)-dependent enzyme that preferentially catalyses the oxidoreduction of oestrogens and androgens. The enzyme belongs to the short-chain dehydrogenase/reductase superfamily and is the only fungal hydroxysteroid dehydrogenase known to date. 17,-HSDcl has recently been characterized and cloned and has been the subject of several functional studies. Although several hypotheses on the physiological role of 17,-HSDcl in fungal metabolism have been formulated, its function is still unclear. An X-ray crystallographic study has been undertaken and the optimal conditions for crystallization of 17,-HSDcl (apo form) were established, resulting in well shaped crystals that diffracted to 1.7,Å resolution. The space group was identified as I4122, with unit-cell parameters a = b = 67.14, c = 266.77,Å. Phasing was successfully performed by Patterson search techniques. A catalytic inactive mutant Tyr167Phe was also engineered, expressed, purified and crystallized for functional and structural studies. [source] DYNAMIC SEARCH SPACE TRANSFORMATIONS FOR SOFTWARE TEST DATA GENERATIONCOMPUTATIONAL INTELLIGENCE, Issue 1 2008Ramón Sagarna Among the tasks in software testing, test data generation is particularly difficult and costly. In recent years, several approaches that use metaheuristic search techniques to automatically obtain the test inputs have been proposed. Although work in this field is very active, little attention has been paid to the selection of an appropriate search space. The present work describes an alternative to this issue. More precisely, two approaches which employ an Estimation of Distribution Algorithm as the metaheuristic technique are explained. In both cases, different regions are considered in the search for the test inputs. Moreover, to depart from a region near to the one containing the optimum, the definition of the initial search space incorporates static information extracted from the source code of the software under test. If this information is not enough to complete the definition, then a grid search method is used. According to the results of the experiments conducted, it is concluded that this is a promising option that can be used to enhance the test data generation process. [source] | ||||||||||||||||