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Best Position (best + position)
Selected AbstractsActive target particle swarm optimizationCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 1 2008Ying-Nan Zhang Abstract We propose an active target particle swarm optimization (APSO). APSO uses a new three-target velocity updating formula, i.e. the best previous position, the global best position and a new target position (called active target). In this study, we distinguish APSO from EPSO (extended PSO)/PSOPC (PSO with passive congregation) by the different methods of getting the active target. Note that here EPSO and PSOPC are the two existing methods for using three-target velocity updating formula, and getting the third (active) target from the obtained positions by the swarm. The proposed APSO gets the active (third) target using complex method, where the active target does not belong to the existing positions. We find that the APSO has the advantages of jumping out of the local optimum and keeping diversity; however, it also has the disadvantages of adding some extra computation expenses. The experimental results show the competitive performance of APSO when compared with PSO, EPSO, and PSOPC. Copyright © 2007 John Wiley & Sons, Ltd. [source] Prevention of secondary stroke and transient ischaemic attack with antiplatelet therapy: the role of the primary care physician roleINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 10 2007H. S. Kirshner Summary Background:, Stroke risk is heightened among patients who have had a primary stroke or transient ischaemic attack (TIA). The primary care physician is in the best position to monitor these patients for stroke recurrence. Because stroke recurrence can occur shortly after the primary event, guidelines recommend initiating antiplatelet therapy as soon as possible. Aspirin, with or without extended-release dipyridamole (ER-DP), and clopidogrel are options for such patients. Low-dose aspirin (75,150 mg/day) has the same efficacy as higher doses but with less gastrointestinal bleeding. Clopidogrel remains an option for prevention of secondary events and may benefit patients with symptomatic atherothrombosis, but its combined use with aspirin can harm patients with multiple risk factors and no history of symptomatic cerebrovascular, cardiovascular or peripheral vascular disease. Results:, Low dose aspirin is effective in secondary stroke prevention. Trials assessing aspirin plus ER-DP have shown that the combination is more effective than aspirin monotherapy in preventing stroke, with efficacy increasing among higher risk patients, notably those with prior stroke/TIA. Clopidogrel does not appear to have as much advantage over aspirin in secondary stroke prevention as aspirin plus ER-DP. Smoking cessation and cholesterol, blood glucose and blood pressure control are also important concerns in preventing recurrent stroke. In choosing pharmacological therapy, the physician must consider the individual patient's risk factors and tolerance, as well as other issues, such as use of aspirin among patients with ulcers. Conclusion:, Antiplatelet therapy is effective in secondary stroke prevention. Low dose aspirin can be used first-line, but aspirin plus ER-DP improves efficacy. Clopidogrel is another option in secondary stroke prevention, especially for aspirin-intolerant patients, but it appears to have less advantage over aspirin than aspirin plus ER-DP, and its combined use with aspirin has only marginally better efficacy and increased bleeding risk. [source] A comparison study on nurses' and therapists' perception on the positioning of stroke patients in Singapore General HospitalINTERNATIONAL JOURNAL OF NURSING PRACTICE, Issue 4 2007Lilian Yew Siew Mee Adv. Before developing a study to evaluate the effect of positioning on outcome after stroke, it was important to explore whether there were differences in perception between neurology/neurosurgery nurses, nurses from other wards, occupational therapists (OTs) and physiotherapists (PTs) over the positioning of stroke patients in Singapore General Hospital (SGH). Questionnaires were sent to 227 nurses, seven PTs and six OTs from six wards where more stroke patients are cared for in SGH. Seventy-two per cent of the respondents identified bed positioning as their positioning strategy. ,Sitting in a chair' was selected as the best position by most of the respondents in the three specialty groups for nursing conscious hemiplegic stroke patients. ,A 30 degree propped-up angle in bed' was selected as the best position by the majority of the nurses from the neuroscience wards while ,lying horizontally on the unaffected side' of the body was selected as the best position by most of the nurses from other wards, PTs and OTs for nursing unconscious hemiplegic stroke patients. However, no significant difference was found between the groups in what they considered the best position for stroke patients. The lack of consensus between these respondents is probably because there are few studies to guide nursing practices for the positioning of stroke patients. Hence, research to confirm which positions improve or hinder outcome after stroke is indispensable. [source] Visions of (In)Security and American Strategic StyleINTERNATIONAL STUDIES PERSPECTIVES, Issue 1 2001Davis B. Bobrow This essay was stimulated (provoked) by discussions in three separate venues: (1) a U.S. Naval War College conference on "Alternative Futures in War and Conflict: Implications for U.S. National Security," held in late 1999; (2) several recent widely circulated "blue-ribbon" reports on the subject; and (3) recent papers emerging from the U.S. defense bureaucracy speculating on strategic visions of the next ten to twenty years. My contention is that the prevailing official and quasi-official debate exhibits excessive and overly definitive emphases on: (1) particular facets of insecurity; (2) attributions to the U.S. of benign intent and capacity; and (3) assumptions that most others share that interpretation of our words and deeds. There also tends to be unwarranted neglect of representation and standing issues which discriminate for and against different policy perspectives and forms of program expertise. A plea is offered for an alternative approach based on what we know about how persons, organizations, and communities can best position themselves for (in)security futures. [source] Socio-economic changes and sacred groves in South India: Protecting a community-based resource management institutionNATURAL RESOURCES FORUM, Issue 2 2004M.G. Chandrakanth Abstract The sacred groves along the forest belts of south India, which were traditionally managed by village communities, are gradually disappearing. This study conducts an analysis of how this community-based resource management institution has evolved over time and what socio-economic factors have caused its gradual disintegration. Commercial agriculture, changing demographics and weak property-rights systems are found to be some of the enabling factors. While the grass-roots enthusiasm to save the sacred groves is still alive, government action is needed to strengthen the traditional village organizations, which are still perhaps in the best position to manage local resources. Several economic and financial incentive mechanisms at the local level that might lead to more efficient and equitable resource use outcomes are suggested. [source] Assessment of selection mapping near the myostatin gene (GDF-8) in cattleANIMAL GENETICS, Issue 5 2009P. Wiener Summary Domestic species provide a unique opportunity to examine the effects of selection on the genome. The myostatin gene (GDF-8) has been under strong selection in a number of cattle breeds because of its influence on muscle conformation and association with the ,double-muscling' phenotype. This study examined genetic diversity near this gene in a set of breeds including some nearly fixed for the allele associated with double-muscling (MH), some where the allele is segregating at intermediate frequency and some where the allele is absent. A set of microsatellites and SNPs were used to examine patterns of diversity at the centromeric end of bovine chromosome 2, the region where GDF-8 is located, using various statistical methods. The putative position of a selected gene was moved across the genomic region to determine, by regression, a best position of reduced heterozygosity. Additional analyses examined extended homozygous regions and linkage disequilibrium patterns. While the SNP data was not found to be very informative for selection mapping in this dataset, analyses of the microsatellite data provided evidence of selection on GDF-8 in several breeds. These results suggested that, of the breeds examined, the allele was most recently introduced into the South Devon. Limitations to the selection-mapping approach were highlighted from the analysis of the SNP data and the situation where the MH allele was at intermediate frequency. [source] Particle swarm optimization algorithm for constrained problemsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2009Jian-Ming Zhang Abstract A novel particle swarm optimization (PSO) algorithm with the evaluation of infeasibility degree (IFD) of constraints is presented for nonlinear programming (NLP) problems with equality and inequality constraints. The IFD of constraints is defined as the sum of the squared values of the constraint violations. The proposed novel PSO updates the local best position and global best position according to the objective value and the value of IFD simultaneously. The results of several numerical tests and one real engineering optimization problem show that the proposed approach is efficient. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] The impact of lower urinary tract symptoms and comorbidities on quality of life: the BACH and UREPIK studiesBJU INTERNATIONAL, Issue 2 2007Chris Robertson In a large epidemiological study, authors investigated the effect of LUTS on quality of life among various cultures. They showed a close association between the two, and that the effect of having moderate symptoms has a similar effect on quality of life as diabetes, hypertension or cancer, and that having severe symptoms had a similar effect as a heart attack or stroke. OBJECTIVES To investigate the effect of lower urinary tract symptoms (LUTS) on quality of life (QoL) and to determine its extent across a variety of cultures, and the confounding effects of self-reported comorbidities and demographics. SUBJECTS AND METHODS Data were obtained from two population-based studies in five cities: UREPIK (Boxmeer, the Netherlands; Auxerre, France; Birmingham, UK; and Seoul, Korea) and the Boston Area Community Health (BACH) study (Boston, USA). UREPIK used stratified random samples of men aged 40,79 years. BACH used a multistage stratified cluster sample to randomly select adults aged 40,79 years. QoL was assessed using a standard Medical Outcomes Study,Short Form 12 (SF-12, mental and physical health component scores); LUTS was assessed using the International Prostate Symptom Score (IPSS). The association between QoL and IPSS, associated illnesses, and lifestyle factors was investigated using weighted regression. RESULTS The UREPIK studied 4800 men aged 40,79 years; BACH recruited 1686 men aged 40,79 years. The prevalence of LUTS, defined as an IPSS of ,8, varied by city (P < 0.001), with Auxerre reporting a prevalence (se) of 18.1 (1.2)%, Birmingham 25.6 (1.5)%, Boston 25.1 (1.6)%, Boxmeer 21.2 (1.3)%, and Seoul 19.0 (1.2)%. Overall, this was similar to the reported rate of high blood pressure. Severe LUTS, defined as an IPSS of ,20, affected , 3.3% of the age group; this was roughly similar to stroke (2.2%), cancer (4.5%), or heart attack (4.5%) and less than half as much as diabetes (8.6%). A 10-point increase in IPSS was associated with a 3.3 (0.3)-point reduction in SF-12 physical health component score, with the same effect in all cities (P = 0.682 for the interaction test). This was more than the physical health component score reduction caused by cancer, diabetes, or high blood pressure (2 points each), but less than stroke or heart attack (6 points). The comorbidities had no significant impact on SF-12 mental health component score (other than a heart attack, that had a 1.8-point reduction). A 10-point increase in IPSS was associated with a 3.4 (0.6)-point reduction of the mental health component score in the four western cities and a 1.4 (0.3)-point reduction in Seoul. CONCLUSIONS Increasingly severe LUTS is associated with a lower QoL. The effect of moderate LUTS on QoL physical health component score is similar to that of having diabetes, high blood pressure or cancer, while the effect of severe LUTS is similar to a heart attack or stroke. These changes were consistent across cultures. This analysis shows the magnitude and consistency of the effects of LUTS on QoL. While these patients might be seen by several types of practitioners, it is likely that urologists will be in the best position to recognize the true impact of LUTS on a patient's QoL, to be aware of the effects of therapies for LUTS on QoL, and to ensure that colleagues in other disciplines recognize the importance of these symptoms and their treatment. [source] Determining arresters best positions in power system for lightning shielding failure protection using simulation optimization approachEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 3 2010B. Vahidi Abstract The lightning stroke to power system structures especially overhead lines makes severe damages and results in less reliable power supply. The invention of surge arresters was a revolution in these systems for protecting the precise equipments from lightning stroke overvoltages. Nowadays, with ever decreasing prices, using arrester not only for protecting certain instruments but also for decreasing total risk of flashover in overall network, is investigated by academic and industrial pioneers in this area. In this paper, our goal is to introduce a heuristic method for determining optimum positions for placing transmission lines surge arresters (TLSAs) with acceptable approximation, to get lowest possible value of shielding failure risk of flashover in a selected set of overhead lines. Simulation optimization based on neural net (i.e. Meta Model) and genetic algorithm (optimization algorithm) is invoked to suggest best positions for placing TLSAs. A case study on Kerman 230,kV network shows good achievement of simulation optimization for finding optimum positions of TLSAs. Comparison is also made with the results of transient simulation to reveal the effectiveness of the method. Copyright © 2008 John Wiley & Sons, Ltd. [source] Escaping parasitism in the selfish herd: age, size and density-dependent warble fly infestation in reindeerOIKOS, Issue 3 2007Per Fauchald It has been suggested that animals may escape attack from mobile parasites by aggregating in selfish herds. A selfish herd disperses the risk of being attacked among its members and the per individual risk of parasite infection should therefore decrease with increasing animal density through the encounter,dilution effect. Moreover, in a selfish herd, dominant and agile animals should occupy the best positions and thereby receive fewer attacks compared to lower ranked animals at the periphery. We tested these predictions on reindeer (Rangifer tarandus tarandus) parasitized by warble flies (Hypoderma tarandi). Warble flies oviposit their eggs on reindeer during summer and induce strong anti-parasitic behavioural responses in the herds. In this period, reindeer are sexually segregated; females and calves form large and dense herds while males are more solitary. After hatching, the warble fly larvae migrate under the skin of their host where they encyst. In the present study encysted larvae were counted on newly slaughtered hides of male calves and 1.5 year old males from 18 different reindeer herds in Finnmark, northern Norway with large contrasts in reindeer density. In reindeer, body mass is correlated with fitness and social status and we hypothesized that individual carcass mass reflected the animal's ability to occupy the best positions within the herd. Larval abundance was higher among the 1.5 year old males than among the calves. For calves we found in accordance with the selfish herd hypothesis a negative relationship between larval abundance and animal density and between larval abundance and body mass. These relationships were absent for the 1.5 year old males. We suggest that these differences were due to different grouping behaviour where calves and females, but not males, aggregated in selfish herds where they escaped parasitism. [source] | |||||||||||||