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Search Process (search + process)
Selected AbstractsSearching PubMed for molecular epidemiology studies: The case of chromosome aberrationsENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2006Donatella Ugolini Abstract The available tools for searching literature in the field of Molecular Epidemiology are largely unsatisfactory. To identify major problems in retrieving information on this discipline, we comment here on the results of a literature search on cytogenetic biomarkers in children exposed to environmental pollutants. The search, done on the PubMed/MedLine database, was based on a strategy combining descriptors listed in the PubMed Medical Subject Headings (MeSH) Thesaurus and other available tools (free text or phrase search tools). 178 articles were retrieved by searching the period from January 1, 1980 to November 30, 2004. Only 2 of the 178 articles were indexed by the MeSH term "Epidemiology, molecular" (introduced in 1994) and 30 of 178 by the MeSH term "Biological markers" (introduced in 1989). The case of chromosome aberration (CA) was emblematic of the problem: 44 of 78 articles (56.4%) were not pertinent to the search. The reasons for this poor performance are reported and discussed. Authors and indexers may be able to improve the efficiency of article retrieval in the field of molecular epidemiology by using relevant terms in the title and abstract. This may suggest appropriate MeSH terms to the indexers for the indexing process. As regards the difficulty in identifiyng population studies using CA, the introduction of a specific MeSH term for chromosome aberrations when used as a biomarker would improve the search process. Environ. Mol. Mutagen., 2006. © 2006 Wiley-Liss, Inc. [source] Opportunistic multiuser scheduling with reduced feedback loadEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 4 2010Yahya S. Al-HarthiArticle first published online: 27 MAY 2010 In this paper, we propose a reduced feedback opportunistic scheduling (RFOS) algorithm that reduces the feedback load while preserving the performance of opportunistic scheduling (OS). The RFOS algorithm is a modified version of our previously proposed algorithm, the DSMUDiv algorithm. The main difference is that RFOS consists of a probing process (search process) and a requesting feedback process based on a threshold. The threshold value is variable, and it depends on the probing process. To reduce the feedback rate, a quantised value indicating the modulation level is fed back, instead of the full value of the signal-to-noise ratio (SNR), which we call quantised SNR. The paper includes the closed-form expressions of the probing load, feedback load and spectral efficiency. In addition, we investigate the effect of the scheduling delay on the system throughput (STH). Under slow Rayleigh fading assumption, we compare RFOS algorithm with the DSMUDiv and optimal (full feedback load) selective diversity scheduling algorithms. Copyright © 2010 John Wiley & Sons, Ltd. [source] Hybrid kernel learning via genetic optimization for TS fuzzy system identificationINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 1 2010Wei Li Abstract This paper presents a new TS fuzzy system identification approach based on hybrid kernel learning and an improved genetic algorithm (GA). Structure identification is achieved by using support vector regression (SVR), in which a hybrid kernel function is adopted to improve regression performance. For multiple-parameter selection of SVR, the proposed GA is adopted to speed up the search process and guarantee the least number of support vectors. As a result, a concise model structure can be determined by these obtained support vectors. Then, the premise parameters of fuzzy rules can be extracted from results of SVR, and the consequent parameters can be optimized by the least-square method. Simulation results show that the resulting fuzzy model not only achieves satisfactory accuracy, but also takes on good generalization capability. Copyright © 2008 John Wiley & Sons, Ltd. [source] The revisit of QoS routing based on non-linear Lagrange relaxationINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2007Gang Feng Abstract The development of efficient quality of service (QoS) routing algorithms in a high-speed networking or the next generation IP networking environment is a very important and at the same time very difficult task due to the need to provide divergent services with multiple QoS requirements. Recently, a heuristic algorithm H_MCOP, which is based on a non-linear Lagrange relaxation (NLR) technique, has been proposed to resolve the contradiction between the time complexity and the quality of solution. Even though H_MCOP has demonstrated outstanding capability of finding feasible solutions to the multi-path constrained (MCP) problem, it has not exploited the full capability that an NLR-based technique could offer. In this paper, we propose a new NLR-based heuristic called NLR_MCP, in which the search process is interpreted from a probability's perspective. Simulation results indicate that NLR_MCP can achieve a higher probability of finding feasible solutions than H_MCOP. We also verify that the performance improvement of a MCP heuristic has a tremendous impact on the performance of a higher level heuristic that uses a MCP heuristic as the basic step. Copyright © 2006 John Wiley & Sons, Ltd. [source] Association between pacifier use and breast-feeding, sudden infant death syndrome, infection and dental malocclusionINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 6 2005Ann Callaghan RN RM BNurs(Hons) Executive summary Objective, To critically review all literature related to pacifier use for full-term healthy infants and young children. The specific review questions addressed are: What is the evidence of adverse and/or positive outcomes of pacifier use in infancy and childhood in relation to each of the following subtopics: ,breast-feeding; ,sudden infant death syndrome; ,infection; ,dental malocclusion. Inclusion criteria, Specific criteria were used to determine which studies would be included in the review: (i) the types of participants; (ii) the types of research design; and (iii) the types of outcome measures. To be included a study has to meet all criteria. Types of participants,The participants included in the review were healthy term infants and healthy children up to the age of 16 years. Studies that focused on preterm infants, and infants and young children with serious illness or congenital malformations were excluded. However, some total population studies did include these children. Types of research design, It became evident early in the review process that very few randomised controlled trials had been conducted. A decision was made to include observational epidemiological designs, specifically prospective cohort studies and, in the case of sudden infant death syndrome research, case,control studies. Purely descriptive and cross-sectional studies were excluded, as were qualitative studies and all other forms of evidence. A number of criteria have been proposed to establish causation in the scientific and medical literature. These key criteria were applied in the review process and are described as follows: (i) consistency and unbiasedness of findings; (ii) strength of association; (iii) temporal sequence; (iv) dose,response relationship; (v) specificity; (vi) coherence with biological background and previous knowledge; (vii) biological plausibility; and (viii) experimental evidence. Studies that did not meet the requirement of appropriate temporal sequencing of events and studies that did not present an estimate of the strength of association were not included in the final review. Types of outcome measures,Our specific interest was pacifier use related to: ,breast-feeding; ,sudden infant death syndrome; ,infection; ,dental malocclusion. Studies that examined pacifier use related to procedural pain relief were excluded. Studies that examined the relationship between pacifier use and gastro-oesophageal reflux were also excluded as this information has been recently presented as a systematic review. Search strategy, The review comprised published and unpublished research literature. The search was restricted to reports published in English, Spanish and German. The time period covered research published from January 1960 to October 2003. A protocol developed by New Zealand Health Technology Assessment was used to guide the search process. The search comprised bibliographic databases, citation searching, other evidence-based and guidelines sites, government documents, books and reports, professional websites, national associations, hand search, contacting national/international experts and general internet searching. Assessment of quality, All studies identified during the database search were assessed for relevance to the review based on the information provided in the title, abstract and descriptor/MeSH terms, and a full report was retrieved for all studies that met the inclusion criteria. Studies identified from reference list searches were assessed for relevance based on the study title. Keywords included: dummy, dummies, pacifier(s), soother(s), comforter(s), non-nutritive sucking, infant, child, infant care. Initially, studies were reviewed for inclusion by pairs of principal investigators. Authorship of articles was not concealed from the reviewers. Next, the methodological quality of included articles was assessed independently by groups of three or more principal investigators and clinicians using a checklist. All 20 studies that were accepted met minimum set criteria, but few passed without some methodological concern. Data extraction, To meet the requirements of the Joanna Briggs Institute, reasons for acceptance and non-acceptance at each phase were clearly documented. An assessment protocol and report form was developed for each of the three phases of review. The first form was created to record investigators' evaluations of studies included in the initial review. Those studies that failed to meet strict inclusion criteria were excluded at this point. A second form was designed to facilitate an in-depth critique of epidemiological study methodology. The checklist was pilot tested and adjustments were made before reviewers were trained in its use. When reviewers could not agree on an assessment, it was passed to additional reviewers and discussed until a consensus was reached. At this stage, studies other than cohort, case,control and randomised controlled trials were excluded. Issues of clarification were also addressed at this point. The final phase was that of integration. This phase, undertaken by the principal investigators, was assisted by the production of data extraction tables. Through a process of trial and error, a framework was formulated that adequately summarised the key elements of the studies. This information was tabulated under the following headings: authors/setting, design, exposure/outcome, confounders controlled, analysis and main findings. Results, With regard to the breast-feeding outcome, 10 studies met the inclusion criteria, comprising two randomised controlled trials and eight cohort studies. The research was conducted between 1995 and 2003 in a wide variety of settings involving research participants from diverse socioeconomic and cultural backgrounds. Information regarding exposure and outcome status, and potential confounding factors was obtained from: antenatal and postnatal records; interviews before discharge from obstetric/midwifery care; post-discharge interviews; and post-discharge postal and telephone surveys. Both the level of contact and the frequency of contact with the informant, the child's mother, differed widely. Pacifier use was defined and measured inconsistently, possibly because few studies were initiated expressly to investigate its relationship with breast-feeding. Completeness of follow-up was addressed, but missing data were not uniformly identified and explained. When comparisons were made between participants and non-participants there was some evidence of differential loss and a bias towards families in higher socioeconomic groups. Multivariate analysis was undertaken in the majority of studies, with some including a large number of sociodemographic, obstetric and infant covariates and others including just maternal age and education. As might be expected given the inconsistency of definition and measurement, the relationship between pacifier use and breast-feeding was expressed in many different ways and a meta-analysis was not appropriate. In summary, only one study did not report a negative association between pacifier use and breast-feeding duration or exclusivity. Results indicate an increase in risk for a reduced overall duration of breast-feeding from 20% to almost threefold. The data suggest that very infrequent use may not have any overall negative impact on breast-feeding outcomes. Six sudden infant death syndrome case,control studies met the criteria for inclusion. The research was conducted with information gathered between 1984 and 1999 in Norway, UK, New Zealand, the Netherlands and USA. Exposure information was obtained from a variety of sources including: hospital and antenatal records, death scene investigation, and interview and questionnaire. Information for cases was sought within 2 days after death, within 2,4 weeks after death and in one study between 3 and 11 years after death. Information for controls was sought from as early as 4 days of a nominated sudden infant death syndrome case, to between 1 and 7 weeks from the case date, and again in one study some 3,11 years later. In the majority of the studies case ascertainment was determined by post-mortem. Pacifier use was again defined and measured somewhat inconsistently. All studies controlled for confounding factors by matching and/or using multivariate analysis. Generally, antenatal and postnatal factors, as well as infant care practices, and maternal, family and socioeconomic issues were considered. All five studies reporting multivariate results found significantly fewer sudden infant death syndrome cases used a pacifier compared with controls. That is, pacifier use was associated with a reduced incidence of sudden infant death syndrome. These results indicate that the risk of sudden infant death syndrome for infants who did not use a pacifier in the last or reference sleep was at least twice, and possibly five times, that of infants who did use a pacifier. Three studies reported a moderately sized positive association between pacifier use and a variety of infections. Conversely, one study found no positive association between pacifier use at 15 months of age and a range of infections experienced between the ages of 6 and 18 months. Given the limited number of studies available and the variability of results, no meaningful conclusions could be drawn. Five cohort studies and one case,control study focused on the relationship between pacifier use and dental malocclusion. Not one of these studies reported a measure of association, such as an estimate of relative risk. It was therefore not possible to include these studies in the final review. Implications for practice, It is intended that this review be used as the basis of a ,best practice guideline', to make health professionals aware of the research evidence concerning these health and developmental consequences of pacifier use, because parents need clear information on which they can base child care decisions. With regard to the association between pacifier use and infection and dental malocclusion it was found that, due to the paucity of epidemiological studies, no meaningful conclusion can be drawn. There is clearly a need for more epidemiological research with regard to these two outcomes. The evidence for a relationship between pacifier use and sudden infant death syndrome is consistent, while the exact mechanism of the effect is not well understood. As to breast-feeding, research evidence shows that pacifier use in infancy is associated with a shorter duration and non-exclusivity. It is plausible that pacifier use causes babies to breast-feed less, but a causal relationship has not been irrefutably proven. Because breast-feeding confers an important advantage on all children and the incidence of sudden infant death syndrome is very low, it is recommended that health professionals generally advise parents against pacifier use, while taking into account individual circumstances. [source] A novel global optimization technique for high dimensional functionsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 4 2009Crina Grosan Several types of line search methods are documented in the literature and are well known for unconstraint optimization problems. This paper proposes a modified line search method, which makes use of partial derivatives and restarts the search process after a given number of iterations by modifying the boundaries based on the best solution obtained at the previous iteration (or set of iterations). Using several high-dimensional benchmark functions, we illustrate that the proposed line search restart (LSRS) approach is very suitable for high-dimensional global optimization problems. Performance of the proposed algorithm is compared with two popular global optimization approaches, namely, genetic algorithm and particle swarm optimization method. Empirical results for up to 2000 dimensions clearly illustrate that the proposed approach performs very well for the tested high-dimensional functions. © 2009 Wiley Periodicals, Inc. [source] Systematic review: role of health promotion in vascular dementiaJOURNAL OF NURSING AND HEALTHCARE OF CHRONIC ILLNE SS: AN INTERNATIONAL INTERDISCIPLINARY JOURNAL, Issue 2 2010BSc(Hons), Rachel S Price MSc price rs & keady j (2010) Journal of Nursing and Healthcare of Chronic Illness 2, 88,101 Systematic review: role of health promotion in vascular dementia Aims., This narrative synthesis of the literature investigates the areas of vascular dementia and modifiable risk factors in order to identify the evidence base and opportunities for specific health promotion work and nursing involvement. Background., Strategies for well-being, prevention and health promotion are becoming increasingly important determinants of a quality dementia care service. In England, this emphasis is manifest in the recently launched National Dementia Strategy (February 2009) and areas that address modifiable vascular risk factors are helpful starting points for the enactment of such goals. Design and methods., A comprehensive search strategy identified primary and secondary search terms that were used systematically in order to search for relevant information and literature; 128 articles were finally included in the overall design and these were broken down into 116 articles obtained through the formal search process using the online databases and 12 articles from the ,grey literature'. Results., A narrative synthesis of the included material generated a thematic framework that revealed four discrete but overlapping themes: vascular risk factors (1); prevention and reduction of vascular risk factors (2); treatment and intervention in vascular dementia (3); and vascular health promotion (4). Relevance to clinical practice., Nursing is in a prime position to undertake health promotion initiatives in modifiable risk behaviours in vascular dementia, an approach that should be commenced for the general population in mid-life (50 years and over). [source] Transitions in search tactics during the Web-based search processJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 11 2010Iris Xie Although many studies have identified search tactics, few studies have explored tactic transitions. This study investigated the transitions of search tactics during the Web-based search process. Bringing their own 60 search tasks, 31 participants, representing the general public with different demographic characteristics, participated in the study. Data collected from search logs and verbal protocols were analyzed by applying both qualitative and quantitative methods. The findings of this study show that participants exhibited some unique Web search tactics. They overwhelmingly employed accessing and evaluating tactics; they used fewer tactics related to modifying search statements, monitoring the search process, organizing search results, and learning system features. The contributing factors behind applying most and least frequently employed search tactics are in relation to users' efforts, trust in information retrieval (IR) systems, preference, experience, and knowledge as well as limitation of the system design. A matrix of search-tactic transitions was created to show the probabilities of transitions from one tactic to another. By applying fifth-order Markov chain, the results also presented the most common search strategies representing patterns of tactic transition occurring at the beginning, middle, and ending phases within one search session. The results of this study generated detailed and useful guidance for IR system design to support the most frequently applied tactics and transitions, to reduce unnecessary transitions, and support transitions at different phases. [source] The self-regulation of curiosity and interest during the information search process of adolescent studentsJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 7 2010Leanne Bowler In a world of increasing information and communications possibilities, the difficulty for users of information systems and services may not lie in finding information but in filtering and integrating it into a cohesive whole. To do this, information seekers must know when and how to effectively use cognitive strategies to regulate their own thinking, motivation, and actions. Sometimes this is difficult when the topic is interesting and one is driven to explore it in great depth. This article reports on a qualitative study that, in the course of exploring the thinking and emotions of 10 adolescents during the information search process, uncovered patterns of behavior that are related to curiosity and interest. The larger purpose of the study was to investigate the metacognitive knowledge of adolescents, ages 16,18, as they searched for, selected, and used information to complete a school-based information task. The study found that the curiosity experienced by adolescents during the search process was accompanied by feelings of both pleasure and pain and that both feelings needed to be managed in order to navigate a pathway through the search process. The self-regulation of curiosity and interest was a clear and distinct metacognitive strategy fueled by metacognitive knowledge related to understanding one's own curiosity and the emotions attached to it. [source] Mining related queries from Web search engine query logs using an improved association rule mining modelJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 12 2007Xiaodong Shi With the overwhelming volume of information, the task of finding relevant information on a given topic on the Web is becoming increasingly difficult. Web search engines hence become one of the most popular solutions available on the Web. However, it has never been easy for novice users to organize and represent their information needs using simple queries. Users have to keep modifying their input queries until they get expected results. Therefore, it is often desirable for search engines to give suggestions on related queries to users. Besides, by identifying those related queries, search engines can potentially perform optimizations on their systems, such as query expansion and file indexing. In this work we propose a method that suggests a list of related queries given an initial input query. The related queries are based in the query log of previously submitted queries by human users, which can be identified using an enhanced model of association rules. Users can utilize the suggested related queries to tune or redirect the search process. Our method not only discovers the related queries, but also ranks them according to the degree of their relatedness. Unlike many other rival techniques, it also performs reasonably well on less frequent input queries. [source] Information-seeking and mediated searching.JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 9 2002Part 1. Our project has investigated the processes of mediated information retrieval (IR) searching during human information-seeking processes to characterize aspects of this process, including information seekers' changing situational contexts; information problems; uncertainty reduction; successive searching, cognitive styles; and cognitive and affective states. The research has involved observational, longitudinal data collection in the United States and United Kingdom. Three questionnaires were used for pre- and postsearch interviews: reference interview, information seeker postsearch, and search intermediary postsearch questionnaires. In addition, the Sheffield team employed a fourth set of instruments in a follow-up interview some 2 months after the search. A total of 198 information seekers participated in a mediated on-line search with a professional intermediary using the Dialog Information Service. Each mediated search process was audio taped and search transaction log recorded. The findings are presented in four parts. Part I presents the background, theoretical framework, models, and research design used during the research. Part II is devoted to exploring changes in information seekers' uncertainty during the mediated process. Part III provides results related to successive searching. Part IV reports findings related to cognitive styles, individual differences, age and gender. Additional articles that discuss further findings from this complex research project, including: (1) an integrated model of information seeking and searching, (2) assessment of mediated searching, and (3) intermediary-information seeker communication, are in preparation and will be published separately. [source] Revisiting search task difficulty: Behavioral and individual difference measuresPROCEEDINGS OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE & TECHNOLOGY (ELECTRONIC), Issue 1 2008Jacek Gwizdka Search task characteristics are recognized as important factors that affect search process and its outcomes. We examine the relationships among operational measures of searcher's behavior, individual cognitive differences, subjective task difficulty and mental effort assessed by dual-task performance. A web-based information study was conduced in a controlled experimental setting. Forty eight study participants performed six search tasks of varying type and structure. Subjective task difficulty was found to be influenced by the searcher's effort measured as the number of result pages and individual documents visited, the number of documents marked as relevant, as well as by individual cognitive differences, and mental effort assessed by performance on the secondary task. In contrast to previous studies, no strong effects of user navigation graph structure were found. [source] The topomer search model: A simple, quantitative theory of two-state protein folding kineticsPROTEIN SCIENCE, Issue 1 2003Dmitrii E. Makarov Abstract Most small, single-domain proteins fold with the uncomplicated, single-exponential kinetics expected for diffusion on a smooth energy landscape. Despite this energetic smoothness, the folding rates of these two-state proteins span a remarkable million-fold range. Here, we review the evidence in favor of a simple, mechanistic description, the topomer search model, which quantitatively accounts for the broad scope of observed two-state folding rates. The model, which stipulates that the search for those unfolded conformations with a grossly correct topology is the rate-limiting step in folding, fits observed rates with a correlation coefficient of ,0.9 using just two free parameters. The fitted values of these parameters, the pre-exponential attempt frequency and a measure of the difficulty of ordering an unfolded chain, are consistent with previously reported experimental constraints. These results suggest that the topomer search process may dominate the relative barrier heights of two-state protein-folding reactions. [source] The Hull and White Model of the Short Rate: An Alternative Analytical RepresentationTHE JOURNAL OF FINANCIAL RESEARCH, Issue 4 2002Dwight Grant Abstract Hull and White extend Ho and Lee's no-arbitrage model of the short interest rate to include mean reversion. This addition eliminates the problem of negative interest rates and has found wide application. To implement their model, Hull and White employ a sequential search process to identify the mean interest rate in a trinomial lattice at each date. In this article we extend Hull and White's work by developing an analytical solution for the mean interest rate at each date. This solution applies equally well to trinomial lattices, interest rate trees, and Monte Carlo simulation. We illustrate the analytical result by applying it to an example originally used by Hull and White and then for valuing an option on a bond. [source] Subject categorization of query terms for exploring Web users' search interestsJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 8 2002Hsiao-Tieh Pu Subject content analysis of Web query terms is essential to understand Web searching interests. Such analysis includes exploring search topics and observing changes in their frequency distributions with time. To provide a basis for in-depth analysis of users' search interests on a larger scale, this article presents a query categorization approach to automatically classifying Web query terms into broad subject categories. Because a query is short in length and simple in structure, its intended subject(s) of search is difficult to judge. Our approach, therefore, combines the search processes of real-world search engines to obtain highly ranked Web documents based on each unknown query term. These documents are used to extract cooccurring terms and to create a feature set. An effective ranking function has also been developed to find the most appropriate categories. Three search engine logs in Taiwan were collected and tested. They contained over 5 million queries from different periods of time. The achieved performance is quite encouraging compared with that of human categorization. The experimental results demonstrate that the approach is efficient in dealing with large numbers of queries and adaptable to the dynamic Web environment. Through good integration of human and machine efforts, the frequency distributions of subject categories in response to changes in users' search interests can be systematically observed in real time. The approach has also shown potential for use in various information retrieval applications, and provides a basis for further Web searching studies. [source] | |||||||||||||||||||