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GA
Terms modified by GA Selected AbstractsAn elaborate education of basic genetic programming using C++COMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 3 2010Nirod C. Sahoo Abstract Evolutionary search is a global search method based on natural selection. In engineering curriculum, these techniques are taught in courses like Evolutionary Computation, Engineering Optimization, etc. Genetic algorithm (GA) is popular among these algorithms. Genetic programming (GP), developed by John Koza, is a powerful extension of GA where a chromosome/computer program (CP) is coded as a rooted point-labeled tree with ordered branches. The search space is the space of all possible CPs (trees) consisting of functions and terminals appropriate to the problem domain. GP uses, like GA, crossover and mutation for evolution. Due to tree-structured coding of individuals, the initial population generation, genetic operators' use, and tree decoding for fitness evaluations demand careful computer programming. This article describes the programming steps of GP implementation (using C++ language) for students' easy understanding with pseudocodes for each step. Two application examples are also illustrated. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 434,448, 2010; View this article online at wileyonlinelibrary.com; DOI 10.1002/cae.20165 [source] Robust Transportation Network Design Under Demand UncertaintyCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 1 2007Satish V. Ukkusuri The origin,destination trip matrices are taken as random variables with known probability distributions. Instead of finding optimal network design solutions for a given future scenario, we are concerned with solutions that are in some sense "good" for a variety of demand realizations. We introduce a definition of robustness accounting for the planner's required degree of robustness. We propose a formulation of the robust network design problem (RNDP) and develop a methodology based on genetic algorithm (GA) to solve the RNDP. The proposed model generates globally near-optimal network design solutions, f, based on the planner's input for robustness. The study makes two important contributions to the network design literature. First, robust network design solutions are significantly different from the deterministic NDPs and not accounting for them could potentially underestimate the network-wide impacts. Second, systematic evaluation of the performance of the model and solution algorithm is conducted on different test networks and budget levels to explore the efficacy of this approach. The results highlight the importance of accounting for robustness in transportation planning and the proposed approach is capable of producing high-quality solutions. [source] Bi-level Programming Formulation and Heuristic Solution Approach for Dynamic Traffic Signal OptimizationCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2006Dazhi Sun Conventional methods of signal timing optimization assume given traffic flow pattern, whereas traffic assignment is performed with the assumption of fixed signal timing. This study develops a bi-level programming formulation and heuristic solution approach (HSA) for dynamic traffic signal optimization in networks with time-dependent demand and stochastic route choice. In the bi-level programming model, the upper level problem represents the decision-making behavior (signal control) of the system manager, while the user travel behavior is represented at the lower level. The HSA consists of a Genetic Algorithm (GA) and a Cell Transmission Simulation (CTS) based Incremental Logit Assignment (ILA) procedure. GA is used to seek the upper level signal control variables. ILA is developed to find user optimal flow pattern at the lower level, and CTS is implemented to propagate traffic and collect real-time traffic information. The performance of the HSA is investigated in numerical applications in a sample network. These applications compare the efficiency and quality of the global optima achieved by Elitist GA and Micro GA. Furthermore, the impact of different frequencies of updating information and different population sizes of GA on system performance is analyzed. [source] Hybrid Meta-Heuristic Algorithm for the Simultaneous Optimization of the O,D Trip Matrix EstimationCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2004Antony Stathopoulos These include a genetic algorithm (GA), a simulated annealing (SA) algorithm, and a hybrid algorithm (GASA) based on the combination of GA and SA. The computational performance of the three algorithms is evaluated and compared by implementing them on a realistic urban road network. The results of the simulation tests demonstrate that SA and GASA produce a more accurate final solution than GA, whereas GASA shows a superior convergence rate, that is, faster improvement from the initial solution, in comparison to SA and GA. In addition, GASA produces a final solution that is more robust and less dependent on the initial demand pattern, in comparison to that obtained from a greedy search algorithm. [source] Genetic Algorithms for Optimal Urban Transit Network DesignCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 3 2003Partha Chakroborty This article attempts to highlight the effectiveness of genetic algorithm (GA),based procedures in solving the urban transit network design problem (UTNDP). The article analyzes why traditional methods have problems in solving the UTNDP. The article also suggests procedures to alleviate these problems using GA,based optimization technique. The thrust of the article is three,fold: (1) to show the effectiveness of GAs in solving the UTNDP, (2) to identify features of the UTNDP that make it a difficult problem for traditional techniques, and (3) to suggest directions, through the presentation of GA,based methodologies for the UTNDP, for the development of GA,based procedures for solving other optimization problems having features similar to the UTNDP. [source] Using GIS, Genetic Algorithms, and Visualization in Highway DevelopmentCOMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2001Manoj K. Jha A model for highway development is presented, which uses geographic information systems (GIS), genetic algorithms (GA), and computer visualization (CV). GIS serves as a repository of geographic information and enables spatial manipulations and database management. GAs are used to optimize highway alignments in a complex search space. CV is a technique used to convey the characteristics of alternative solutions, which can be the basis of decisions. The proposed model implements GIS and GA to find an optimized alignment based on the minimization of highway costs. CV is implemented to investigate the effects of intangible parameters, such as unusual land and environmental characteristics not considered in optimization. Constrained optimization using GAs may be performed at subsequent stages if necessary using feedback received from CVs. Implementation of the model in a real highway project from Maryland indicates that integration of GIS, GAs, and CV greatly enhances the highway development process. [source] Physical foundations, models, and methods of diffusion magnetic resonance imaging of the brain: A reviewCONCEPTS IN MAGNETIC RESONANCE, Issue 5 2007Ludovico Minati Abstract The foundations and characteristics of models and methods used in diffusion magnetic resonance imaging, with particular reference to in vivo brain imaging, are reviewed. The first section introduces Fick's laws, propagators, and the relationship between tissue microstructure and the statistical properties of diffusion of water molecules. The second section introduces the diffusion-weighted signal in terms of diffusion of magnetization (Bloch,Torrey equation) and of spin-bearing particles (cumulant expansion). The third section is dedicated to the rank-2 tensor model, the bb -matrix, and the derivation of indexes of anisotropy and shape. The fourth section introduces diffusion in multiple compartments: Gaussian mixture models, relationship between fiber layout, displacement probability and diffusivity, and effect of the b -value. The fifth section is devoted to higher-order generalizations of the tensor model: singular value decompositions (SVD), representation of angular diffusivity patterns and derivation of generalized anisotropy (GA) and scaled entropy (SE), and modeling of non-Gaussian diffusion by means of series expansion of Fick's laws. The sixth section covers spherical harmonic decomposition (SHD) and determination of fiber orientation by means of spherical deconvolution. The seventh section presents the Fourier relationship between signal and displacement probability (Q -space imaging, QSI, or diffusion-spectrum imaging, DSI), and reconstruction of orientation-distribution functions (ODF) by means of the Funk,Radon transform (Q -ball imaging, QBI). © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 278,307, 2007. [source] Using parallelization and hardware concurrency to improve the performance of a genetic algorithmCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 4 2007Vijay Tirumalai Abstract Genetic algorithms (GAs) are powerful tools for solving many problems requiring the search of a solution space having both local and global optima. The main drawback for GAs is the long execution time normally required for convergence to a solution. This paper discusses three different techniques that can be applied to GAs to improve overall execution time. A serial software implementation of a GA designed to solve a task scheduling problem is used as the basis for this research. The execution time of this implementation is then improved by exploiting the natural parallelism present in the algorithm using a multiprocessor. Additional performance improvements are provided by implementing the original serial software GA in dedicated reconfigurable hardware using a pipelined architecture. Finally, an advanced hardware implementation is presented in which both pipelining and duplicated hardware modules are used to provide additional concurrency leading to further performance improvements. Copyright © 2006 John Wiley & Sons, Ltd. [source] Prevalence of Sleep Disordered Breathing in a Heart Failure ProgramCONGESTIVE HEART FAILURE, Issue 5 2004Robin J. Trupp MSN Recent data show that a high percentage of patients with systolic left ventricular dysfunction have sleep-disordered breathing (SDB), contributing to the incidence of morbidity and mortality in heart failure. This study examines the prevalence of sleep disorders in stable heart failure patients regardless of ejection fraction. On three consecutive days in a heart failure clinic, all patients were asked to participate in a screening for SDB. This screening involved the placement of an outpatient device (ClearPath, Nexan, Inc., Alpharetta, GA), which collects thoracic impedance, oxyhemoglobin saturation, and 2-lead electrocardiogram data. Sixteen patients (42%) had moderate or severe SDB, and 22 patients (55%) had mild or no significant SDB. Fourteen of the 16 patients with moderate or severe SDB subsequently received treatment by confirming SDB and the continuous positive airway pressure in a sleep lab. Forty-two percent of patients with stable heart failure presenting to a heart failure clinic screened positive for SDB, despite receiving optimal standard of care. [source] NON-GYNAECOLOGICAL CYTOLOGY: THE CLINICIAN'S VIEWCYTOPATHOLOGY, Issue 2006I. Penman There is increased recognition of the importance of accurate staging of malignancies of the GI tract and lung, greater use of neoadjuvant therapies and more protocol-driven management. This is particularly important where regional lymph node involvement significantly impacts on curability. Multidetector CT and PET scanning have resulted in greater detection of potential abnormalities which, if positive for malignancy, would change management. There is also a greater recognition that many enlarged nodes may be inflammatory and that size criteria alone are unreliable in determining involvement. In other situations, especially pancreatic masses, not all represent carcinoma as focal chronic pancreatitis, autoimmune pancreatitis etc can catch out the unwary. A preoperative tissue diagnosis is essential and even if unresectable, oncologists are increasingly reluctant to initiate chemotherapy or enroll patients into trials without this. The approach to obtaining tissue is often hampered by the small size or relative inaccessibility of lesions by percutaneous approaches. As such novel techniques such as endoscopic ultrasound (EUS) guided FNA have been developed. A 120cm needle is passed through the instrument and, under real-time visualisation, through the gastrointestinal wall to sample adjacent lymph nodes or masses. Multiple studies have demonstrated the safety and performance of this technique. In oesophageal cancer, confirmation of node positivity by has a major negative influence on curative resection rates and will often lead to a decision to use neoadjuvant chemotherapy or a non-operative approach. Sampling of lymph nodes at the true coeliac axis upstages the patient to M1a status (stage IV) disease and makes the patient incurable. In NSCLC, subcarinal lymph nodes are frequently present but may be inflammatory. If positive these represent N2 (stage IIIA) disease and in most centres again makes the patient inoperable. Access to these lymph nodes would otherwise require mediastinosocopy whereas this can be done simply, safely and quickly by EUS. Overall the sensitivity for EUS , FNA of mediastinal or upper abdominal lymph nodes is 83,90% with an accuracy of 80,90%. In pancreatic cancer performance is less good but pooled analysis of published studies indicates a sensitivity of 85% and accuracy of 88%. In a recent spin-off from EUS, endobronchial ultrasound (EBUS) instruments have been developed and the ability to sample anterior mediastinal nodes has been demonstrated. It is likely that this EBUS , FNA technique will become increasingly utilised and may replace mediastinoscopy. The development of techniques such as EUS and EBUS to allow FNA sampling of lesions has increased the role of non-gynaecological cytology significantly in recent years. Cytology therefore remains important for a broad range of specialties and there is ongoing need for careful and close co-operation between cytologists and clinicians in these specialties. References:, 1. Williams DB, Sahai AV, Aabakken L, Penman ID, van Velse A, Webb J et al. Endoscopic ultrasound guided fine needle aspiration biopsy: a large single centre experience. Gut. 1999; 44: 720,6. 2. Silvestri GA, Hoffman BJ, Bhutani MS et al. Endoscopic ultrasound with fine-needle aspiration in the diagnosis and staging of lung cancer. Ann Thorac Surg 1996; 61: 1441,6. 3. Rintoul RC, Skwarski KM, Murchison JT, Wallace WA, Walker WS, Penman ID. Endobronchial and endoscopic ultrasound real-time fine-needle aspiration staging of the mediastinum ). Eur Resp J 2005; 25: 1,6. [source] Illicit substance use and its correlates in first episode psychosisACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2010R. Mazzoncini Mazzoncini R, Donoghue K, Hart J, Morgan C, Doody GA, Dazzan P, Jones PB, Morgan K, Murray RM, Fearon P. Illicit substance use and its correlates in first episode psychosis. Objective:, To determine if substance use (particularly cannabis) is more frequent among first episode psychosis patients and associated with a more problematic clinical presentation. Method:, All first episode psychosis (FEP) patients presenting to secondary services were recruited from London and Nottingham, over 2 years, in the Aetiology and Ethnicity of Schizophrenia and Other Psychoses study broad framework. Clinical and sociodemographic variables were assessed using a set of standardized instruments. A schedule was created to retrospectively collate substance use data from patients, relatives and clinicians. Results:, Five hundred and eleven FEP were identified. They used three to five times more substances than general population. Substance use was associated with poorer social adjustment and a more acute mode of onset. Cannabis use did not affect social adjustment, but was associated with a more acute mode of onset. Conclusion:, Cannabis has a different impact on FEP than other substances. Large epidemiological studies are needed to disentangle cannabis effect. [source] The Efficacy of EMLA versus ELA-Max for Pain Relief in Medium-Depth Chemical Peeling: A Clinical and Histopathologic EvaluationDERMATOLOGIC SURGERY, Issue 1 2000Robert A. Koppel MD Background. Medium-depth chemical peels are an effective and popular treatment for actinic damage, fine wrinkles, and pigmentary dyschromias. However, they are also uncomfortable. A previous attempt to study the effectiveness of a topical anesthetic gel in 35% trichloroacetic acid (TCA) peeling found a reduction in discomfort but an increased depth of penetration and delayed healing. Objective. To evaluate both the efficacy of two topical anesthetic agents in medium-depth combination peeling as well as the histologic result from chemical peeling combined with topical anesthesia. Method. Seventy percent glycolic acid (GA) was applied to the entire face of 10 patients and diluted with water after 2 minutes. This was followed by the sequential application of EMLA cream (lidocaine 2.5% and prilocaine 2.5%), ELA-Max cream (lidocaine 4%), and placebo to selected areas on the face for 30 minutes without occlusion. These agents were then removed and 35% TCA was applied to the entire face. The level of discomfort felt by the patients during the TCA peel was recorded, clinical photographs were taken, and bilateral preauricular biopsies were performed at baseline, 48 hours, and 90 days postoperatively. Results. Clinically there was a statistically significant decrease in pain felt during the 70% GA-35% TCA peel with topical anesthesia when compared to the control. There was no statistically significant difference in efficacy between EMLA and ELA-Max. There was also no difference in either the clinical or the histopathologic appearance between the medium-depth peel combined with topical anesthesia and the medium-depth peel with control. Conclusion. Both EMLA and ELA-Max decrease the discomfort felt during medium-depth combination chemical peeling without influencing either the clinical or the histopathologic result. [source] Assessment of gestational age and neuromaturationDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 1 2005Marilee C. Allen Abstract Neuromaturation is the functional development of the central nervous system (CNS). It is by its very nature a dynamic process, a continuous interaction between the genome and first the intrauterine environment, then the extrauterine environment. Understanding neuromaturation and being able to measure it is fundamental to infant neurodevelopmental assessment. Fetal and preterm neuromaturation has become easier to observe with the advent of prenatal ultrasonography and neonatal intensive care units. A number of measures of degree of fetal maturation have been developed and used to estimate gestational age (GA) at birth. The most reliable measures of GA are prenatal measures, especially from the first trimester. Postnatal GA measurements tend to be least accurate at the extremes of gestation, that is, in extremely preterm and post-term infants. Observations of measures of neuromaturation in infants born to mothers with pregnancy complications, including intrauterine growth restriction, multiple gestation, and chronic hypertension, have led to the discovery that stressed pregnancies may accelerate fetal pulmonary and CNS maturation. This acceleration of neuromaturation does not occur before 30 weeks' gestation and has a cost with respect to cognitive limitations manifested in childhood. The ability to measure fetal and preterm neuromaturation provides an assessment of neurodevelopmental progress that can be used to reassure parents or identify at risk infants who would benefit from limited comprehensive follow-up and early intervention services. In addition, measures of neuromaturation have the potential to provide insight into mechanisms of CNS injury and recovery, much-needed early feedback in intervention or treatment trials and a measure of early CNS function for research into the relationships between CNS structure and function. © 2005 Wiley-Liss, Inc. MRDD Research Reviews 2005;11:21,33. [source] Immediate effect of percutaneous intramuscular stimulation during gait in children with cerebral palsy: a feasibility studyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2005Margo N Orlin PT PhD PCS The feasibility of percutaneous intramuscular functional electrical stimulation (P-FES) in children with cerebral palsy (CP) for immediate improvement of ankle kinematics during gait has not previously been reported. Eight children with CP (six with diplegia, two with hemiplegia; mean age 9 years 1 month [SD 1y 4mo; range 7y 11mo to 11y 10mo]) had percutaneous intramuscular electrodes implanted into the gastrocnemius (GA) and tibialis anterior (TA) muscles of their involved limbs. Stimulation was provided during appropriate phases of the gait cycle in three conditions (GA only, TA only, and GA/TA). Immediately after a week of practice for each stimulation condition, a gait analysis was performed with and without stimulation. A significant improvement in peak dorsiflexion in swing for the more affected extremity and dorsiflexion at initial contact for the less affected extremity were found in the GA/TA condition. Clinically meaningful trends were evident for improvements in dorsiflexion kinematics for the more and less affected extremities in the TA only and GA/TA conditions. The results suggest that P-FES might immediately improve ankle kinematics in children with CP. [source] Maturation of fetal responses to musicDEVELOPMENTAL SCIENCE, Issue 5 2004B.S. Kisilevsky Maturation of fetal response to music was characterized over the last trimester of pregnancy using a 5-minute piano recording of Brahms' Lullaby, played at an average of 95, 100, 105 or 110 dB (A). Within 30 seconds of the onset of the music, the youngest fetuses (28,32 weeks GA) showed a heart rate increase limited to the two highest dB levels; over gestation, the threshold level decreased and a response shift from acceleration to deceleration was observed for the lower dB levels, indicating attention to the stimulus. Over 5 minutes of music, fetuses older than 33 weeks GA showed a sustained increase in heart rate; body movement changes occurred at 35 weeks GA. These findings suggest a change in processing of complex sounds at around 33 weeks GA, with responding limited to the acoustic properties of the signal in younger fetuses but attention playing a role in older fetuses. [source] Risk factors for suicide attempts in patients with alcohol dependence or abuse and a history of depressive symptoms: A subgroup analysis from the WHO/ISBRA studyDRUG AND ALCOHOL REVIEW, Issue 1 2010ÖZGÜR YALDIZLI Abstract Introduction and Aims. Alcoholism, depression and suicide attempts (SA) are strongly interrelated. The aims were to determine risk factors and develop a prognostic predictor model for SA in a subgroup of patients with a history of alcohol dependence or abuse and depressive symptoms. Design and Methods. A subgroup analysis from the data of the World Health Organisation (WHO)/the International Society for Biomedical Research on Alcoholism (ISBRA)-collaborative study on biological state and trait marker of alcohol use and dependence, an international multi-centre study with a cross-sectional design, based on a standardised questionnaire. We analysed from 1314 variables 43 factors,including demographic characteristics, dependence variables, comorbid disorders, personality trait markers and family history,that were supposed to be most predictive for SA according to the literature. Correlation analyses by the ,2 -test and Mann,Whitney U -test were performed to obtain statistical meaningful parameters for logistic regression analysis. Results. Of the 1863 persons included in the WHO/ISBRA study, 292 had both a history of depressive symptoms and alcohol dependence or abuse and were included in the subgroup analysis. In the logistic regression analysis, drinking status, depressive symptoms, adverse drinking experiences during alcohol consumption, bad experiences from drug abuse and antidepressant therapy were found to be independent risk factors for SA. Positive family history of alcoholism was a model-improving co-factor. This predictive model explains approximately 60% of the variance (Nagelkerkes' square). Discussion and Conclusions. This prognostic model derived from data of the WHO/ISBRA collaborative study shows important risk factors for SA in patients with history of alcohol abuse or dependence and depressive symptoms. [ Yaldizli Ö, Kuhl HC, Graf M, Wiesbeck GA, Wurst FM. Risk factors for suicide attempts in patients with alcohol dependence or abuse and a history of depressive symptoms: A subgroup analysis from the WHO/ISBRA study. Drug Alcohol Rev 2009] [source] Output-only structural identification in time domain: Numerical and experimental studiesEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 4 2008M. J. Perry Abstract By identifying changes in stiffness parameters, structural damage can be detected and monitored. Although considerable progress has been made in this research area, many challenges remain in achieving robust structural identification based on incomplete and noisy measurement signals. The identification task is made even more difficult if measurement of input force is to be eliminated. To this end, an output-only structural identification strategy is proposed to identify unknown stiffness and damping parameters. A non-classical approach based on genetic algorithms (GAs) is adopted. The proposed strategy makes use of the recently developed GA-based method of search space reduction, which has shown to be able to accurately and reliably identify structural parameters from measured input and output signals. By modifying the numerical integration scheme, input can be computed as the parameter identification task is in progress, thereby eliminating the need to measure forces. Numerical and experimental results demonstrate the power of the strategy in accurate and efficient identification of structural parameters and damage using only incomplete acceleration measurements. Copyright © 2007 John Wiley & Sons, Ltd. [source] Branching probabilities planning of stochastic network model using genetic algorithm supported by sensitivity analysisELECTRICAL ENGINEERING IN JAPAN, Issue 4 2008Kenzo Kurihara This paper proposes a new method of planning the project durations that are modeled as stochastic networks such as GERT networks. Since stochastic networks have a variable time and a branching probability for each arrow, the total duration of the network is also modeled as a variable. In order to complete the project by the desired date with a certain confidence, the variable times or branching probabilities of the network should be designed appropriately. We will propose a planning method for branching probabilities to realize the desired project duration using GA and Monte Carlo simulation. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 43,53, 2008; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20582 [source] Voltammetric Sensor for Sodium Nitroprusside Determination in Biological Fluids Using Films of Poly- L -LysineELECTROANALYSIS, Issue 9 2007Claudece Pereira, Francisco Abstract Sodium nitroprusside (NP), a commercial vasodilator, can be pre-concentrated on vitreous carbon electrode modified by films of 97.5%: 2.5% poly- L -lysine (PLL): glutaraldehyde (GA). This coating gives acceptable anion exchange properties whilst giving the required improvement of adhesion to the glassy carbon electrode surface. Linear response range and detection limit on nitroprusside in B-R buffer pH,4.0, were 1×10,6 to 2×10,5 mol L,1 and 1×10,7 mol L,1, respectively. The repeatability of the proposed sensor, evaluated in term of relative standard deviation, was measured as 4.1% for 10 experiments. The voltammetric sensor was directly applied to determination of nitroprusside in human plasma and urine samples and the average recovery for these samples was around 95,97% without any pre treatment. [source] A new genetic algorithm with diploid chromosomes using probability decoding for adaptation to various environmentsELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 8 2010Manabu Kominami Abstract This paper proposes a new diploid operation technique using probability for function optimization in nonstationary environments and describes a feature of diploid genetic algorithms (GAs). The advantage of the technique over previous diploid GAs is that one genotype is transformed into many phenotypes based on probability. This transformation is not made at random. It has a certain range of probabilities. Each individual has a range. The range allows adaptation to various environments. The technique allows genes to give a probabilistic representation of dominance, and can maintain the diversity of individuals. The experimental results show that the technique can adapt to severe environmental changes where previous diploid GAs cannot adapt. This paper shows that the technique can find optimum solutions with high probability and that the distribution of individuals changes when the environment changes. In addition, by comparing the proposed diploid GA with a haploid GA whose chromosome is twice the length, the features of the diploid are described. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(8): 38,46, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10097 [source] A design for robust power system stabilizer by means of H, control and particle swarm optimization methodELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 8 2008Yoshifumi Zoka Abstract This paper proposes two types of PSS design methods that take into account robustness for comparably large power systems. The first one is a design method based on , control theory and the second one is a parameter determination method for a standard PSS by using Particle Swarm Optimization (PSO). In order to deal with large-scale systems, a reduced model is developed to get the target system which preserves major oscillation modes only. The major oscillation modes are selected by using the residue concept, and the PSS is designed based on the target system. In order to verify effectiveness, the proposed methods are compared with the other previously proposed method based on a Genetic Algorithm (GA) through many numerical simulations. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(8): 34,43, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10132 [source] Virus-evolutionary linear genetic programmingELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 1 2008Kenji Tamura Abstract Many kinds of evolutionary methods have been proposed. GA and GP in particular have demonstrated their effectiveness in various problems recently, and many systems have been proposed. One is Virus-Evolutionary Genetic Algorithm (VE-GA), and the other is Linear Genetic Programming in C (LGPC). The performance of each system has been reported. VE-GA is the coevolution system of host individuals and virus individuals. That can spread schema effectively among the host individuals by using virus infection and virus incorporation. LGPC implements the GP by representing the individuals to one dimension as if GA. LGPC can reduce a search cost of pointer and save machine memory, and can reduce the time to implement GP programs. We have proposed that a system introduce virus individuals in LGPC, and analyzed the performance of the system on two problems. Our system can spread schema among the population, and search solution effectively. The results of computer simulation show that this system can search for solution depending on LGPC applying problem's character compared with LGPC. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(1): 32, 39, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10030 [source] Genotoxicity of acrylamide and its metabolite glycidamide administered in drinking water to male and female Big Blue mice,ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2006Mugimane G. Manjanatha Abstract The recent discovery of acrylamide (AA), a probable human carcinogen, in a variety of fried and baked starchy foods has drawn attention to its genotoxicity and carcinogenicity. Evidence suggests that glycidamide (GA), the epoxide metabolite of AA, is responsible for the genotoxic effects of AA. To investigate the in vivo genotoxicity of AA, groups of male and female Big Blue (BB) mice were administered 0, 100, or 500 mg/l of AA or equimolar doses of GA, in drinking water, for 3,4 weeks. Micronucleated reticulocytes (MN-RETs) were assessed in peripheral blood within 24 hr of the last treatment, and lymphocyte Hprt and liver cII mutagenesis assays were conducted 21 days following the last treatment. Further, the types of cII mutations induced by AA and GA in the liver were determined by sequence analysis. The frequency of MN-RETs was increased 1.7,3.3-fold in males treated with the high doses of AA and GA (P , 0.05; control frequency = 0.28%). Both doses of AA and GA produced increased lymphocyte Hprt mutant frequencies (MFs), with the high doses producing responses 16,25-fold higher than that of the respective control (P , 0.01; control MFs = 1.5 ± 0.3 × 10,6 and 2.2 ± 0.5 × 10,6 in females and males, respectively). Also, the high doses of AA and GA produced significant 2,2.5-fold increases in liver cII MFs (P , 0.05; control MFs = 26.5 ± 3.1 × 10,6 and 28.4 ± 4.5 × 10,6). Molecular analysis of the mutants indicated that AA and GA produced similar mutation spectra and that these spectra were significantly different from that of control mutants (P , 0.001). The predominant types of mutations in the liver cII gene from AA- and GA-treated mice were G:C,T:A transversions and ,1/+1 frameshifts in a homopolymeric run of Gs. The results indicate that both AA and GA are genotoxic in mice. The MFs and types of mutations induced by AA and GA in the liver are consistent with AA exerting its genotoxicity in BB mice via metabolism to GA. Environ. Mol. Mutagen., 2006. Published 2005 Wiley-Liss, Inc. [source] Converting waste gases from pulp mills into value-added chemicalsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2002Tom L. Burgess A combined sorption/catalytic process has been discovered that converts the methanol and mercaptans in Kraft pulp mill waste gas condensates into formaldehyde. A pilot plant was operated at Georgia-Pacific's Brunswick, GA, mill for two years to optimize both sorbents and catalyst. Patents were issued. Applications within Georgia-Pacific and external licensing opportunities for the process are being investigated. The process gives pulp and paper mills a profitable alternative for converting their waste gases to valuable chemicals, as opposed to incineration or biodegradation in treatment ponds. [source] A pilot-scale demonstration of a membrane-based absorption- stripping process for removal and recovery of volatile organic compoundsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2001S. Majumdar A new membrane-based continuous absorption-stripping process has been developed to separate gas/vapor mixtures, such as volatile organic compounds (VOCs), from a nitrogen/air stream. Two different hollow fiber membrane modules are needed in this process to remove the VOCs. In the first module, VOC-laden nitrogen/air stream flows through the bore of the hollow fibers. A suitable absorbent liquid with a high solubility for the VOC and essentially no solubility for nitrogen/air is pumped countercurrently over the outside of the fibers. This liquid is an inert, nontoxic, and essentially nonvolatile, organic solvent. The VOCs are effectively removed from nitrogen/air to a very low level and are concentrated in the absorbent for recovery, while the absorbent is regenerated by heating and subjecting it to vacuum in a separate hollow fiber membrane module called the stripping module. A pilot-scale membrane-based absorption-stripping unit was located next to a paint spray booth at Robins Air Force Base, Warner Robins, GA. Tests were performed on slip-streams of real-time air emissions from scheduled intermittent painting operations, so the concentration of VOC in the exhaust air fluctuated with time. The VOC removal efficiency was determined as a function of the feed air flow rate and the absorbent (silicone oil) flow rate. Depending on the gas/liquid flow rates and the inlet VOC concentration, the process successfully removed as much as 95+% of the VOC present. The experimental results have been compared with theoretical predictions. [source] Dissolved fraction of standard laboratory cladoceran food alters toxicity of waterborne silver to Ceriodaphnia dubia,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2008Jason M. Kolts Abstract The biotic ligand model (BLM) for the acute toxicity of cationic metals to aquatic organisms incorporates the toxicity-modifying effects of dissolved organic matter (DOM), but the default parameterization (i.e., assuming 10% of DOM is humic acid) does not differentiate DOM from different sources. We exposed a cladoceran (Ceriodaphnia dubia) to Ag in the presence of DOM from filtered YCT (standard yeast,Cerophyll®,trout chow food recommended by the U.S. Environmental Protection Agency [EPA] for cladocerans), from the Suwannee River (GA, USA; relatively little anthropogenic input), and from the Desjardins Canal in Hamilton (ON, Canada; receives treated municipal wastewater effluent). In all three treatments, the dissolved organic carbon (DOC) concentration was 2 mg/L (the concentration following addition of YCT slurry at the U.S. EPA,recommended volume ratio). The average 48-h median effects concentration (EC50) ratios for dissolved Ag in the presence and absence of DOM [i.e., (EC50 with DOM)/(EC50 without DOM)] were as follows: Suwannee River, 1.6; Desjardins Canal, 2.2; and YCT filtrate, 26.8. Therefore, YCT filtrate provided much more protection against Ag toxicity than that provided by DOM from the surface waters. The major spectral characteristic that differentiated YCT filtrate from the other two types of DOM was a strong tryptophan peak in the excitation,emission matrix for YCT. These results have important implications for interpreting Ag toxicity tests in which organisms are fed YCT, and they suggest BLM-calculated toxicity predictions might be improved by incorporating specific chemical constituents or surrogate indices of DOM. Another component of the protective effect against Ag toxicity, however, might be that the dissolved fraction of YCT served as an energy and/or nutrient source for C. dubia. [source] General Anesthesia and the Ketogenic Diet: Clinical Experience in Nine PatientsEPILEPSIA, Issue 5 2002Ignacio Valencia Summary: ,Purpose: To determine if children actively on the ketogenic diet (KD) can safely undergo general anesthesia (GA) for surgical procedures. Methods: The records of children treated with the KD at Children's Hospital (Boston, Massachusetts) from 1995 to the present were reviewed. The charts of children who had received GA while on the diet were evaluated with regard to demographics, procedure information, anesthesia records, blood chemistries, and perioperative course. Of 71 children on the KD during the period of the study, nine (12.7%) had procedures requiring GA while on the diet. Results: Nine children received GA for surgical procedures ranging from central line placement to hemispherectomy while on the KD. At the time of GA, the children ranged from age 1 to 6 years, and had been on the KD for 2,60 months. The patients received carbohydrate-free intravenous solutions perioperatively. Anesthesia duration ranged from 20 min to 11.5 h; for longer procedures, serum pH, glucose, and electrolyte levels were monitored. Serum glucose levels remained stable in all patients, but serum pH typically decreased; the largest reduction was to 7.16. In three procedures, patients received intravenous bicarbonate because of level of acidosis. There were no perioperative complications. Conclusions: Children on the KD can safely undergo GA for surgical procedures. Although serum glucose levels appear to remain stable, serum pH or bicarbonate levels should be monitored because of the risk of metabolic acidosis. [source] Short-term cortisol infusion in the brachial artery, with and without inhibiting 11,-hydroxysteroid dehydrogenase, does not alter forearm vascular resistance in normotensive and hypertensive subjectsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 12 2002S. H. M. Van Uum Abstract Background Vascular tone is increased in primary hypertension, and glucocorticoids affect vascular tone. Local cortisol availability is modulated by activity of 11,-hydroxysteroid dehydrogenase (11,-HSD). As this activity may be decreased in patients with primary hypertension, vascular sensitivity to cortisol may be increased in these patients. We studied the acute effect of cortisol on forearm vascular resistance (FVR) by infusing cortisol directly into the brachial artery, both with and without inhibition of 11,-HSD, in normotensive and hypertensive subjects. Design Twenty normotensive volunteers and 20 patients with primary hypertension participated in the study. After a 10-min infusion of vehicle (glucose 5%), cortisol was infused into the brachial artery in three stepwise increasing doses (3·5, 10·5 and 35 µg per 100 mL of forearm volume), each for 10 min. Next, the participants received placebo or 500 mg glycyrrhetinic acid (GA) orally, and 150 min later the same infusion schedule was repeated. Forearm vascular resistance was measured during the last 5 min of the infused vehicle and of each dose. Arterial and forearm venous plasma samples for measurement of cortisol and cortisone were taken at the end of the infusions of glucose 5% and the highest cortisol dose. Results In both normotensive and hypertensive subjects, neither the infusion of cortisol nor the administration of GA changed FVR. Also 2 h after the cortisol infusion there remained no change in FVR in both the normotensive and hypertensive groups who received placebo. Following the infusion of the highest cortisol dose, total plasma cortisone levels in the venous plasma were decreased compared with levels in the arterial plasma (36 ± 3 and 49 ± 4 nmol L,1, respectively, P < 0·05). The protein-bound venous cortisone was 37·1 ± 4·8 nmol L,1 during the vehicle compared with 23·9 ± 3·7 nmol L,1 during the cortisol infusion (P < 0·01), whereas the free cortisone level was not altered by the cortisol infusion. Conclusions In both normotensive and hypertensive subjects, high-dose cortisol infusion both with and without 11,-HSD inhibition did not change FVR either immediately or after 2 h. We could not demonstrate in vivo 11,-HSD activity in the forearm vascular tissues. When binding of cortisone to CBG is changed, e.g. during cortisol infusion, arterio-venous changes in cortisone cannot reliably be used to assess (alterations in) local 11,-HSD activity. [source] Serum transferrin receptor, ferritin, and reticulocyte maturity indices during the first year of life in ,large' preterm infantsEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2007Vassiliki Schiza Abstract Background:, Preterm infants are at risk of developing iron deficiency; among the iron status and hemopoiesis indices the serum transferrin receptor (sTfr) has been shown to be a useful indicator in assessing iron status, while immature reticulocyte production is regarded as an estimator of erythropoiesis. Objective:, To investigate age-related changes in iron status infants born ,moderately' preterm, with a gestational age (GA) of 32,36 wk, and identify associations between sTfr and other hematological and biochemical iron indices. Design:, Hospital-based prospective, longitudinal study in preterm infants. Methods:, Iron and erythropoiesis parameters were evaluated in 181 formula-fed preterm infants at 2 and 6 wk and 3, 6, 9, and 12 months chronological age. Hemoglobulin (Hb), hematocrit (Hct), mean corpuscular volume (MCV), reticulocytes, serum iron (sFe), serum ferritin (sFer), sTfr, and reticulocyte subpopulations were measured. Results:, A total of 756 measurements were performed. After an initial decline, Hb rose from month 3 to 12 of life. SFe and sFer and immature reticulocyte count decreased from the second week to the third month and remained stable thereafter. STfr was lower up to 6 wk and stable from month 3 to 12. Iron deficiency anemia (IDA) was found in 5.5% of infants. In 76 measurements sFer was <12 ,g/L, implying storage iron deficiency (SID). A negative correlation was observed between sTfr and other indices of iron status such as Hb, Hct, MCV, sFe, and sFer. Infants with sFer <12 ,g/L had lower sTfr than those with sFer >12 ,g/L. Reticulocyte production was positively associated with STfr, but this association was dependent on the chronological age of the infant. Conclusion:, Iron depletion is common in formula-fed preterm (32,36 wk GA) infants between month 3 and 12 of life. STfr appears to be an indicator of iron status in preterm infants during the first year of life. [source] Visualization of local Ca2+ dynamics with genetically encoded bioluminescent reportersEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2005Kelly L. Rogers Abstract Measurements of local Ca2+ signalling at different developmental stages and/or in specific cell types is important for understanding aspects of brain functioning. The use of light excitation in fluorescence imaging can cause phototoxicity, photobleaching and auto-fluorescence. In contrast, bioluminescence does not require the input of radiative energy and can therefore be measured over long periods, with very high temporal resolution. Aequorin is a genetically encoded Ca2+ -sensitive bioluminescent protein, however, its low quantum yield prevents dynamic measurements of Ca2+ responses in single cells. To overcome this limitation, we recently reported the bi-functional Ca2+ reporter gene, GFP-aequorin (GA), which was developed specifically to improve the light output and stability of aequorin chimeras [V. Baubet, et al., (2000) PNAS, 97, 7260,7265]. In the current study, we have genetically targeted GA to different microdomains important in synaptic transmission, including to the mitochondrial matrix, endoplasmic reticulum, synaptic vesicles and to the postsynaptic density. We demonstrate that these reporters enable ,real-time' measurements of subcellular Ca2+ changes in single mammalian neurons using bioluminescence. The high signal-to-noise ratio of these reporters is also important in that it affords the visualization of Ca2+ dynamics in cell,cell communication in neuronal cultures and tissue slices. Further, we demonstrate the utility of this approach in ex-vivo preparations of mammalian retina, a paradigm in which external light input should be controlled. This represents a novel molecular imaging approach for non-invasive monitoring of local Ca2+ dynamics and cellular communication in tissue or whole animal studies. [source] | ||||||||||||||||||||||||||||||||||||||||||||||