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Hybrid Approach (hybrid + approach)
Selected AbstractsA Hybrid Approach to Multiple Fluid Simulation using Volume FractionsCOMPUTER GRAPHICS FORUM, Issue 2 2010Nahyup Kang Abstract This paper presents a hybrid approach to multiple fluid simulation that can handle miscible and immiscible fluids, simultaneously. We combine distance functions and volume fractions to capture not only the discontinuous interface between immiscible fluids but also the smooth transition between miscible fluids. Our approach consists of four steps: velocity field computation, volume fraction advection, miscible fluid diffusion, and visualization. By providing a combining scheme between volume fractions and level set functions, we are able to take advantages of both representation schemes of fluids. From the system point of view, our work is the first approach to Eulerian grid-based multiple fluid simulation including both miscible and immiscible fluids. From the technical point of view, our approach addresses the issues arising from variable density and viscosity together with material diffusion. We show that the effectiveness of our approach to handle multiple miscible and immiscible fluids through experiments. [source] Hybrid Approach to the Synthesis of Highly Luminescent CdTe/ZnS and CdHgTe/ZnS Nanocrystals.CHEMINFORM, Issue 18 2004James M. Tsay Abstract For Abstract see ChemInform Abstract in Full Text. [source] Review of Urban Stormwater Quality Models: Deterministic, Stochastic, and Hybrid Approaches,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2007Christopher C. Obropta Abstract:, The growing impact of urban stormwater on surface-water quality has illuminated the need for more accurate modeling of stormwater pollution. Water quality based regulation and the movement towards integrated urban water management place a similar demand for improved stormwater quality model predictions. The physical, chemical, and biological processes that affect stormwater quality need to be better understood and simulated, while acknowledging the costs and benefits that such complex modeling entails. This paper reviews three approaches to stormwater quality modeling: deterministic, stochastic, and hybrid. Six deterministic, three stochastic, and three hybrid models are reviewed in detail. Hybrid approaches show strong potential for reducing stormwater quality model prediction error and uncertainty. Improved stormwater quality models will have wide ranging benefits for combined sewer overflow management, total maximum daily load development, best management practice design, land use change impact assessment, water quality trading, and integrated modeling. [source] Hybrid approach with an expert system and a genetic algorithm to production management in the supply netINTELLIGENT SYSTEMS IN ACCOUNTING, FINANCE & MANAGEMENT, Issue 1-2 2006awrynowicz A new approach to solving production management problems in the supply net is proposed. An expert system designed to help companies in medium-term and short-term production planning is discussed. The proposed expert system considers alternative process plans for a job and outsourcing, when a bottleneck exists in the machine. The proposed hybrid system uses the output of the expert system as the input of the genetic algorithm. The output of the genetic algorithm is a near optimal schedule. The proposed method does not require any unrealistic assumptions. It can be used to solve highly complicated and non-linear functions of a realistic problem. Copyright © 2007 John Wiley & Sons, Ltd. [source] Atrial septal interventions in patients with hypoplastic left heart syndrome,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 5 2008Ralf J. Holzer MD Abstract Objectives: To report an institutional experience performing percutaneous atrial septal interventions in patients with hypoplastic left heart syndrome (HLHS). Background: The success of the Hybrid approach in palliating patients with HLHS is crucially dependant on relieving any significant interatrial restriction. Data on transcatheter interventions to relieve atrial septal restrictions in patients with HLHS are limited. Methods: We retrospectively reviewed 67 transcatheter atrial septal interventions that were performed between July 2002 and September 2007 in 56 patients with HLHS. The median weight was 3.35 kg. About 10.7% of patients had an intact atrial septum. Balloon atrial septostomy (BAS) was used in 77.6% of procedures, additional techniques in 35.8% of procedures. Patients were divided into those with standard atrial septal anatomy (group A, n = 33) and those with complex atrial septal anatomy (group B, n = 23). Results: The mean trans-septal gradient was reduced significantly from 7 mm Hg to 1 mm Hg with the median time to discharge being 3.5 days. Major adverse events were seen in 8.9% of procedures, whereas minor adverse events occurred in 26.8% of procedures. Adverse events were significantly less common in patients with standard atrial septal anatomy, compared to those with complex atrial septal anatomy (25.6% versus 50.0%). About 19.6% patients required repeated atrial septal interventions. Survival up to and including Comprehensive stage II palliation was 73% group A, and 57% in group B. Conclusions: With utilization of appropriate techniques and equipment, atrial septal interventions in HLHS can be performed successfully in virtually all patients. Complex atrial septal anatomy is technically challenging and has a higher incidence of procedural adverse events. In the majority of patients, standard BAS can be performed safely, and is usually the only intervention required to achieve adequate relief of atrial septal restriction until Comprehensive stage II palliation. © 2008 Wiley-Liss, Inc. [source] Review of Urban Stormwater Quality Models: Deterministic, Stochastic, and Hybrid Approaches,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 6 2007Christopher C. Obropta Abstract:, The growing impact of urban stormwater on surface-water quality has illuminated the need for more accurate modeling of stormwater pollution. Water quality based regulation and the movement towards integrated urban water management place a similar demand for improved stormwater quality model predictions. The physical, chemical, and biological processes that affect stormwater quality need to be better understood and simulated, while acknowledging the costs and benefits that such complex modeling entails. This paper reviews three approaches to stormwater quality modeling: deterministic, stochastic, and hybrid. Six deterministic, three stochastic, and three hybrid models are reviewed in detail. Hybrid approaches show strong potential for reducing stormwater quality model prediction error and uncertainty. Improved stormwater quality models will have wide ranging benefits for combined sewer overflow management, total maximum daily load development, best management practice design, land use change impact assessment, water quality trading, and integrated modeling. [source] EXPO2009: structure solution by powder data in direct and reciprocal spaceJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2009Angela Altomare The program EXPO2009 is the evolution of EXPO2004 [Altomare, Caliandro, Camalli, Cuocci, Giacovazzo, Moliterni & Rizzi (2004). J. Appl. Cryst. 37, 1025,1028]. EXPO2009 performs all the steps of ab initio structure solution by powder data: indexing, space-group determination, estimation of the reflection integrated intensities, structure solution by direct/Patterson methods and/or by a direct-space/hybrid approach, and model refinement by the Rietveld technique. New procedures have been introduced in EXPO2009 for enhancing the structure solution process, particularly in the case of low-resolution data and/or organic compounds, when traditional approaches like direct methods may fail. The EXPO2009 graphical interface has been optimized and made very user friendly. [source] A hybrid approach for simulating human motion in constrained environmentsCOMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2010Jia Pan Abstract We present a new algorithm to generate plausible motions for high-DOF human-like articulated figures in constrained environments with multiple obstacles. Our approach is general and makes no assumptions about the articulated model or the environment. The algorithm combines hierarchical model decomposition with sample-based planning to efficiently compute a collision-free path in tight spaces. Furthermore, we use path perturbation and replanning techniques to satisfy the kinematic and dynamic constraints on the motion. In order to generate realistic human-like motion, we present a new motion blending algorithm that refines the path computed by the planner with motion capture data to compute a smooth and plausible trajectory. We demonstrate the results of generating motion corresponding to placing or lifting object, walking, and bending for a 38-DOF articulated model. Copyright © 2010 John Wiley & Sons, Ltd. [source] A Hybrid Approach to Multiple Fluid Simulation using Volume FractionsCOMPUTER GRAPHICS FORUM, Issue 2 2010Nahyup Kang Abstract This paper presents a hybrid approach to multiple fluid simulation that can handle miscible and immiscible fluids, simultaneously. We combine distance functions and volume fractions to capture not only the discontinuous interface between immiscible fluids but also the smooth transition between miscible fluids. Our approach consists of four steps: velocity field computation, volume fraction advection, miscible fluid diffusion, and visualization. By providing a combining scheme between volume fractions and level set functions, we are able to take advantages of both representation schemes of fluids. From the system point of view, our work is the first approach to Eulerian grid-based multiple fluid simulation including both miscible and immiscible fluids. From the technical point of view, our approach addresses the issues arising from variable density and viscosity together with material diffusion. We show that the effectiveness of our approach to handle multiple miscible and immiscible fluids through experiments. [source] Gossip-based search selection in hybrid peer-to-peer networksCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 2 2008M. Zaharia Abstract We present GAB, a search algorithm for hybrid peer-to-peer networks, that is, networks that search using both flooding and a distributed hash table (DHT). GAB uses a gossip-style algorithm to collect global statistics about document popularity to allow each peer to make intelligent decisions about which search style to use for a given query. Moreover, GAB automatically adapts to changes in the operating environment. Synthetic and trace-driven simulations show that compared to a simple hybrid approach that always floods first, trying a DHT if too few results are found, GAB reduces the response time by 25,50% and the average query bandwidth cost by 45%, with no loss in recall. GAB scales well, with only a 7% degradation in performance despite a tripling in system size. Copyright © 2007 John Wiley & Sons, Ltd. [source] Deep Start: a hybrid strategy for automated performance problem searchesCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11-12 2003Philip C. Roth Abstract To attack the problem of scalability of performance diagnosis tools with respect to application code size, we have developed the Deep Start search strategy,a new technique that uses stack sampling to augment an automated search for application performance problems. Our hybrid approach locates performance problems more quickly and finds performance problems hidden from a more straightforward search strategy. The Deep Start strategy uses stack samples collected as a by-product of normal search instrumentation to select deep starters, functions that are likely to be application bottlenecks. With priorities and careful control of the search refinement, our strategy gives preference to experiments on the deep starters and their callees. This approach enables the Deep Start strategy to find application bottlenecks more efficiently and more effectively than a more straightforward search strategy. We implemented the Deep Start search strategy in the Performance Consultant, Paradyn's automated bottleneck detection component. In our tests, Deep Start found half of our test applications' known bottlenecks between 32% and 59% faster than the Performance Consultant's current search strategy, and finished finding bottlenecks between 10% and 61% faster. In addition to improving the search time, Deep Start often found more bottlenecks than the call graph search strategy. Copyright © 2003 John Wiley & Sons, Ltd. [source] Rhythm Management in Pediatric Heart FailureCONGENITAL HEART DISEASE, Issue 4 2006Charles I. Berul MD ABSTRACT There are several options now available for the management of arrhythmias and ventricular dysfunction in pediatric patients with heart failure. A hybrid approach that combines the expertise of heart failure and electrophysiology specialists may be well suited for the optimal management of these complex patients. Medical and device therapies may be synergistic in decreasing the morbidity and mortality in pediatric heart failure. Pediatric electrophysiology can now potentially offer therapies that can help prevent both arrhythmic and pump failure deaths, as well as improve functional capacity and quality of life. These therapies and the available supporting data relevant to pediatrics will be the focus of this review. [source] Monitoring Lung Resistivity Changes in Congestive Heart Failure Patients Using the Bioimpedance TechniqueCONGESTIVE HEART FAILURE, Issue 6 2005Sharon Zlochiver MSc The feasibility of a novel, dedicated system for monitoring lung resistivity in congestive heart failure patients, implementing a hybrid approach of the bioimpedance technique, was assessed in this preliminary study. Thirty-three healthy volunteers and 34 congestive heart failure patients were measured with the PulmoTrace system (Cardiolnspect, Tel Aviv University, Tel Aviv, Israel) during tidal respiration, and the ability to monitor the respective lung resistivity values was assessed. Mean left and right lung resistivity values of 1205±163 and 1200±165 ,·cm for the control group and 888±193 and 943±187 ,·cm for the congestive heart failure group were found, indicating a significant (p<2·10,7) difference between the two groups. The results of long-term monitoring of two patients during medical treatment are also shown. This hybrid approach system is believed to improve diagnostic capabilities and help physicians to better adjust medication dosage on a frequent basis. [source] The Laser-Assisted Neck Lift: Modifications in Technique and Postoperative Care to Improve ResultsDERMATOLOGIC SURGERY, Issue 6 2002F. Richard Noodleman MD background. Conventional submental tumescent liposuction has proved disappointing for some patients with anterior neck laxity, ptotic platysma muscles, and increased subplatysmal fat. Many of these patients are facelift candidates but are unwilling to undergo this extensive procedure. We describe our hybrid approach, which offers consistently improved results and enhanced patient satisfaction. objective. To establish a sharper cervicomental angle by more completely removing subplatysmal fat. We also wished to achieve more consistent, smoother results, minimizing ripples, folds, and hematomas with a novel postoperative dressing system. methods. Extensive tumescent liposuction of the lower face, jowls, and anterior neck was performed. Following this, subplatysmal fat was removed by dissection, the platysma muscle was imbricated, and the CO2 laser utilized in a defocused, low-power mode to partially treat the dermal undersurface and underlying muscle. Our postoperative dressing included a 10 cm mineral oil polymer gel disc in the submental location, covered by tape, silicone foam, and a lower face and neck garment to provide both support and even compression over the entire neck for at least the first 24 hours. results. Results proved uniformly satisfying for most patients, even those in their senior years. Benefits included an improved cervicomental angle, a decrease in jowling, and a marked reduction in the laxity and wrinkling of the neck skin and horizontal neck creases. Problems related to postoperative rippling or folding of the redraped skin and hematoma formation were minimized. conclusion. Laser neck tightening combined with tumescent liposuction and an advanced postoperative dressing for superior support and uniform compression has resulted in consistently excellent outcomes with improved patient satisfaction. [source] Relative accuracy and predictive ability of direct valuation methods, price to aggregate earnings method and a hybrid approachACCOUNTING & FINANCE, Issue 4 2006Lucie Courteau M41 Abstract In this paper, we assess the relative performance of the direct valuation method and industry multiplier models using 41 435 firm-quarter Value Line observations over an 11 year (1990,2000) period. Results from both pricing-error and return-prediction analyses indicate that direct valuation yields lower percentage pricing errors and greater return prediction ability than the forward price to aggregated forecasted earnings multiplier model. However, a simple hybrid combination of these two methods leads to more accurate intrinsic value estimates, compared to either method used in isolation. It would appear that fundamental analysis could benefit from using one approach as a check on the other. [source] Molecules on Si: Electronics with ChemistryADVANCED MATERIALS, Issue 2 2010Ayelet Vilan Abstract Basic scientific interest in using a semiconducting electrode in molecule-based electronics arises from the rich electrostatic landscape presented by semiconductor interfaces. Technological interest rests on the promise that combining existing semiconductor (primarily Si) electronics with (mostly organic) molecules will result in a whole that is larger than the sum of its parts. Such a hybrid approach appears presently particularly relevant for sensors and photovoltaics. Semiconductors, especially Si, present an important experimental test-bed for assessing electronic transport behavior of molecules, because they allow varying the critical interface energetics without, to a first approximation, altering the interfacial chemistry. To investigate semiconductor-molecule electronics we need reproducible, high-yield preparations of samples that allow reliable and reproducible data collection. Only in that way can we explore how the molecule/electrode interfaces affect or even dictate charge transport, which may then provide a basis for models with predictive power. To consider these issues and questions we will, in this Progress Report, review junctions based on direct bonding of molecules to oxide-free Si. describe the possible charge transport mechanisms across such interfaces and evaluate in how far they can be quantified. investigate to what extent imperfections in the monolayer are important for transport across the monolayer. revisit the concept of energy levels in such hybrid systems. [source] Nanoscale Logic Circuits: Hybrid Complementary Logic Circuits of One-Dimensional Nanomaterials with Adjustment of Operation Voltage (Adv. Mater.ADVANCED MATERIALS, Issue 21 200921/2009) A new layout of complementary logic circuits based on p-channel carbon nanotube and n-channel zinc oxide nanowire transistors is presented by Takhee Lee and co-workers on p. 2156. The processing is a hybrid approach, combining advantageous characteristic functions for the modulation of the current and operating voltage in transistors through proton radiation-generated charges, allowing a simple method of designing favorable logic circuits. [source] Hybrid Complementary Logic Circuits of One-Dimensional Nanomaterials with Adjustment of Operation VoltageADVANCED MATERIALS, Issue 21 2009Gunho Jo A new layout of complementary logic circuits based on p-channel carbon nanotube and n-channel zinc oxide nanowire transistors is presented, providing a hybrid approach to combine advantageous characteristic functions for the modulation of the current and operating voltage in transistors through proton radiation-generated charges, which allow a simple way to design favorable logic circuits. [source] Assessing the predictive performance of artifIcial neural network-based classifiers based on different data preprocessing methods, distributions and training mechanismsINTELLIGENT SYSTEMS IN ACCOUNTING, FINANCE & MANAGEMENT, Issue 4 2005Adrian Costea We analyse the implications of three different factors (preprocessing method, data distribution and training mechanism) on the classification performance of artificial neural networks (ANNs). We use three preprocessing approaches: no preprocessing, division by the maximum absolute values and normalization. We study the implications of input data distributions by using five datasets with different distributions: the real data, uniform, normal, logistic and Laplace distributions. We test two training mechanisms: one belonging to the gradient-descent techniques, improved by a retraining procedure, and the other is a genetic algorithm (GA), which is based on the principles of natural evolution. The results show statistically significant influences of all individual and combined factors on both training and testing performances. A major difference with other related studies is the fact that for both training mechanisms we train the network using as starting solution the one obtained when constructing the network architecture. In other words we use a hybrid approach by refining a previously obtained solution. We found that when the starting solution has relatively low accuracy rates (80,90%) the GA clearly outperformed the retraining procedure, whereas the difference was smaller to non-existent when the starting solution had relatively high accuracy rates (95,98%). As reported in other studies, we found little to no evidence of crossover operator influence on the GA performance. Copyright © 2005 John Wiley & Sons, Ltd. [source] Numerical solution of eddy current problems in ferromagnetic bodies travelling in a transverse magnetic fieldINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2003W. Peterson Abstract Eddy currents are investigated in a ferromagnetic bar travelling in a transverse magnetic field. Such an open boundary field problem is analysed by a hybrid approach based on Galerkin finite element formulation coupled with a separation of variables. A steady state is considered, introducing time-periodic boundary conditions. The resultant system of non-linear equations is solved by an iterative procedure based on Brouwer's fixed-point theorem. Numerical results are presented for a bar of circular cross-section made of cast steel or cast iron. Selected examples of the field distribution and characteristics of eddy-current power losses are enclosed in graphic form. Copyright © 2003 John Wiley & Sons, Ltd. [source] High-frequency transmission through metallic single-walled carbon nanotube interconnectsINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 5 2009M. S. Tahvili Abstract In this paper, high-frequency transmission behavior of metallic single-walled carbon nanotube (SWCNT) interconnects is investigated. The SWCNT is assumed to be lying over a doped Si substrate, in a transmission line configuration. A hybrid approach, combining quantum theory with classical distributed-element model is utilized to predict dynamical performance of the metallic SWCNT as a nano transmission line. Several aspects of high-frequency performance of such interconnect, including the effect of SWCNT length and substrate doping level, is studied. A novel modification is proposed to take damping mechanisms effect caused by the imperfect conductance of substrate into account. The results show that the impact of limited conductivity of the substrate determines the dynamical behavior of short SWCNTs; whereas in case of long nanotubes, damping effects that arise from scattering mechanisms are dominant. Copyright © 2009 John Wiley & Sons, Ltd. [source] Do Hierarchical Condition Category Model Scores Predict Hospitalization Risk in Newly Enrolled Medicare Advantage Participants as Well as Probability of Repeated Admission Scores?JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 12 2009David G. Mosley MHA OBJECTIVES: To compare how well hierarchical condition categories (HCC) and probability of repeated admission (PRA) scores predict hospitalization. DESIGN: Longitudinal cohort study with 12-month follow-up. SETTING: A Medicare Advantage (MA) plan. PARTICIPANTS: Four thousand five hundred six newly enrolled beneficiaries. MEASUREMENT: HCC scores were identified from enrollment files. The PRA tool was administered by mail and telephone. Inpatient admissions were based on notifications. The Mann-Whitney test was used to compare HCC scores of PRA responders and nonresponders. The receiver operating characteristic curve provided the area under the curve (AUC) for each score. Admission risk in the top 5% of scores was evaluated using logistic regression. RESULTS: Within 60 days of enrollment, 45.1% of the 3,954 beneficiaries with HCC scores completed the PRA tool. HCC scores were lower for the 1,783 PRA respondents than the 2,171 nonrespondents (0.71 vs 0.81, P<.001). AUCs predicting hospitalization with regard to HCC and PRA were similar (0.638, 95% confidence interval (CI)=0.603,0.674; 0.654, 95% CI=0.618,0.690). Individuals identified in the top 5% of scores using both tools, using HCC alone, or using PRA alone had higher risk for hospitalization than those below the 95th percentile (odds ratio (OR)=8.5, 95% CI=3.7,19.4, OR=3.8, 95% CI=2.3,6.3, and OR=3.9, 95% CI=2.3,6.4, respectively). CONCLUSION: HCC scores provided to MA plans for risk adjustment of revenue can also be used to identify hospitalization risk. Additional studies are required to evaluate whether a hybrid approach incorporating administrative and self-reported models would further optimize risk stratification efforts. [source] Reduction in Atrial Defibrillation Threshold by a Single Linear Ablation LesionJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2001JAMES B. WHITE Ph.D. Single Lesion Lowers ADFT.Introduction: This study investigated a hybrid approach to reduce the atrial defibrillation threshold (ADFT) by determining the effect of a single linear radiofrequency ablation (RFA) lesion on both the ADFT and activation patterns during atrial fibrillation (AF). Methods and Results: In 18 open chest sheep (45 to 57 kg), coil defibrillation electrodes were placed in a superior vena cava/right ventricular configuration. AF was induced by burst pacing and maintained with acetyl ,-methylcholine (2 to 42 ,L/min). ADFTs were obtained before and after a linear RFA lesion was created in the left atrium (LAL; n = 6), right atrium (RAL; n = 6), or neither atrium as a control (n = 6). In animals receiving an LAL, a 504-unipolar-electrode plaque was sutured to the LA. For animals receiving an RAL, two 504-electrode plaques were placed, one each on the LA and RA. From each plaque, activations were recorded before and after ADFT shocks, and organizational characteristics of activations were analyzed using algorithms that track individual wavefronts. In sham-treated controls, the ADFT did not change. In contrast, LAL reduced ADFT energy 29%, from 4.5 ± 2.3 J to 3.2 ± 2.0 J (P < 0.05). RAL reduced ADFT energy 25%, from 2.0 ± 0.9 J to 1.5 ± 0.7 J (P < 0.05). AF activation was substantially more organized after RFA than before RFA for both the RAL- and LAL-treated animals. Conclusion: A single RFA lesion in either the RA or LA reduces the ADFT in this sheep model. This decrease is associated with an increase in fibrillatory organization. [source] A hybrid forecasting approach for piece-wise stationary time seriesJOURNAL OF FORECASTING, Issue 7 2006Minxian Yang Abstract We consider the problem of forecasting a stationary time series when there is an unknown mean break close to the forecast origin. Based on the intercept-correction methods suggested by Clements and Hendry (1998) and Bewley (2003), a hybrid approach is introduced, where the break and break point are treated in a Bayesian fashion. The hyperparameters of the priors are determined by maximizing the marginal density of the data. The distributions of the proposed forecasts are derived. Different intercept-correction methods are compared using simulation experiments. Our hybrid approach compares favorably with both the uncorrected and the intercept-corrected forecasts.,,Copyright © 2006 John Wiley & Sons, Ltd. [source] Scoring ligand similarity in structure-based virtual screeningJOURNAL OF MOLECULAR RECOGNITION, Issue 4 2009Maria I. Zavodszky Abstract Scoring to identify high-affinity compounds remains a challenge in virtual screening. On one hand, protein,ligand scoring focuses on weighting favorable and unfavorable interactions between the two molecules. Ligand-based scoring, on the other hand, focuses on how well the shape and chemistry of each ligand candidate overlay on a three-dimensional reference ligand. Our hypothesis is that a hybrid approach, using ligand-based scoring to rank dockings selected by protein,ligand scoring, can ensure that high-ranking molecules mimic the shape and chemistry of a known ligand while also complementing the binding site. Results from applying this approach to screen nearly 70,000 National Cancer Institute (NCI) compounds for thrombin inhibitors tend to support the hypothesis. EON ligand-based ranking of docked molecules yielded the majority (4/5) of newly discovered, low to mid-micromolar inhibitors from a panel of 27 assayed compounds, whereas ranking docked compounds by protein,ligand scoring alone resulted in one new inhibitor. Since the results depend on the choice of scoring function, an analysis of properties was performed on the top-scoring docked compounds according to five different protein,ligand scoring functions, plus EON scoring using three different reference compounds. The results indicate that the choice of scoring function, even among scoring functions measuring the same types of interactions, can have an unexpectedly large effect on which compounds are chosen from screening. Furthermore, there was almost no overlap between the top-scoring compounds from protein,ligand versus ligand-based scoring, indicating the two approaches provide complementary information. Matchprint analysis, a new addition to the SLIDE (Screening Ligands by Induced-fit Docking, Efficiently) screening toolset, facilitated comparison of docked molecules' interactions with those of known inhibitors. The majority of interactions conserved among top-scoring compounds for a given scoring function, and from the different scoring functions, proved to be conserved interactions in known inhibitors. This was particularly true in the S1 pocket, which was occupied by all the docked compounds. Copyright © 2009 John Wiley & Sons, Ltd. [source] Hybrid DEM-compartment modeling approach for granular mixingAICHE JOURNAL, Issue 1 2007Patricia M. Portillo Abstract A new hybrid approach to model powder mixing based on the use of discrete element method (DEM) and compartment modeling is presented. The main motivation behind the proposed approach is to reduce the computational expense of modeling powder mixing by partitioning the mixing system into high shear areas that are modeled using detailed DEM simulations, whereas the remaining process is simulated using stochastic models. The approach can, thus, be used to model complex geometries, as well as a large number of particles that is typically unfeasible with the existing approaches. The results of a horizontal convective mixing vessel are used to illustrate the applicability and efficiency of the proposed approach. © 2006 American Institute of Chemical Engineers AIChE J 2007 [source] A hybrid approach to Web forum interactional coherence analysisJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 8 2008Tianjun Fu Despite the rapid growth of text-based computer-mediated communication (CMC), its limitations have rendered the media highly incoherent. This poses problems for content analysis of online discourse archives. Interactional coherence analysis (ICA) attempts to accurately identify and construct CMC interaction networks. In this study, we propose the Hybrid Interactional Coherence (HIC) algorithm for identification of web forum interaction. HIC utilizes a bevy of system and linguistic features, including message header information, quotations, direct address, and lexical relations. Furthermore, several similarity-based methods including a Lexical Match Algorithm (LMA) and a sliding window method are utilized to account for interactional idiosyncrasies. Experiments results on two web forums revealed that the proposed HIC algorithm significantly outperformed comparison techniques in terms of precision, recall, and F-measure at both the forum and thread levels. Additionally, an example was used to illustrate how the improved ICA results can facilitate enhanced social network and role analysis capabilities. [source] Reconfigurable photonic crystal circuitsLASER & PHOTONICS REVIEWS, Issue 2 2010C. Grillet Abstract We describe progress in the field of tuning, (re)configuration of Photonic crystal (PhC) based devices with a particular emphasis on our recent concepts and techniques that we have developed to tune and/or reconfigure the properties of photonic crystal nanocavities. We show how our hybrid approach based on photosensitive material and tapered silica fiber can tune the (Q, ,) properties of preexisting Photonic crystal cavities. We describe our alternative techniques to create ,a posteriori' spatially (re)configurable high-Q cavities in a PhC platform. We show that optofluidics , the fusion of microfluidics with photonic devices , offers an unquestionable added value to the quest of a truly versatile, (re)configurable photonic crystal based photonic chip. [source] A Hybrid Galerkin,Monte-Carlo Approach to Higher-Dimensional Population Balances in Polymerization KineticsMACROMOLECULAR REACTION ENGINEERING, Issue 9-10 2010Christof Schütte Abstract Population balance models describing not only the chain-length distribution of a polymer but also additional properties like branching or composition are still difficult to solve numerically. For simulation of such systems two essentially different approaches are discussed in the literature: deterministic solvers based on rate equations and stochastic Monte-Carlo (MC) strategies based on chemical master equations. The paper presents a novel hybrid approach to polymer reaction kinetics that combines the best of these two worlds. We discuss the theoretical conditions of the algorithm, describe its numerical realization, and show that, if applicable, it is more efficient than full-scale MC approaches and leads to more detailed information in additional property indices than deterministic solvers. [source] Ant colony based hybrid approach for optimal compromise sum-difference patterns synthesisMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010P. Rocca Abstract Dealing with the synthesis of monopulse array antennas, many stochastic optimization algorithms have been used for the solution of the so-called optimal compromise problem between sum and difference patterns when sub-arrayed feed networks are considered. More recently, hybrid approaches, exploiting the convexity of the functional with respect to a sub-set of the unknowns (i.e., the sub-array excitation coefficients) have demonstrated their effectiveness. In this letter, an hybrid approach based on the ant colony optimization (ACO) is proposed. At the first step, the ACO is used to define the sub-array membership of the array elements, while, at the second step, the sub-array weights are computed by solving a convex programming problem. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 128,132, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24882 [source] | ||||||||||||||||||||||||||||||||||