The ALP-PALS project: optimal coupling for laser propulsion
Boody, F. P.; Badziak, J.; Eckel, H. A.; Gammino, S.; Krasa, J.; Laska, L.; Mezzasalma, A.; Pakhomov, A. J.; Parys, P.; Pfeifer, M.; Rohlena, K.; Schall, W.; Torrisi, L.; Wolowski, J.
2005-10-01
Ablative laser propulsion (ALP) could revolutionize space travel by reducing the 30:1 propellant/payload ratio needed for near-earth orbit 50-fold. Experiments to date have demonstrated the necessary efficiency, coupling coefficient, and specific impulse for application, but were performed at pulse energies and spot sizes much smaller than required and at wavelengths not usable in the atmosphere. Prior experiments have also not simultaneously measured the properties of the ions produced or of the ablated surface, properties that would allow full understanding of the propulsion properties in terms of ion characteristics. The first realistic measurements of laser propulsion parameters are proposed using PALS (Prague Asterix Laser System), the important parameters of which (pulse energy (similar to 1 kJ), pulse length (400 ps), beam diameter (similar to 29 cm), and flat beam profile) equal those required for application. The PALS wavelength is a little short (1.3 mu mvs. > 1.5 mu m) but is closer than any other laser available and PALS' 2 omega/omega capability should allow extrapolation to application values. The PALS proven infrastructure for measuring laser-driven ion properties means that only a ballistic pendulum for measuring momentum transfer will have to be added.
Rabin, Sam; Alexander, Peter; Anthoni, Peter; Henry, Roslyn; Huntingford, Chris; Pugh, Thomas; Rounsevell, Mark; Arneth, Almut
2017-04-01
A major question facing humanity is how well agricultural production systems will be able to feed the world in a future of rapid climate change, population growth, and demand shifts—all while minimizing our impact on the natural world. Global modeling has frequently been used to investigate certain aspects of this question, but in order to properly address the challenge, no one part of the human-environmental system can be assessed in isolation. It is especially critical that the effect on agricultural yields of changing temperature and precipitation regimes (including seasonal timing and frequency and intensity of extreme events), as well as rising atmospheric carbon dioxide levels, be taken into account when planning for future food security. Coupled modeling efforts, where changes in various parts of the Earth system are allowed to feed back onto one another, represent a powerful strategy in this regard. This presentation describes the structure and initial results of an effort to couple a biologically-representative vegetation and crop production simulator, LPJ-GUESS, with the climate emulator IMOGEN and the land-use model PLUMv2. With IMOGEN providing detailed future weather simulations, LPJ-GUESS simulates natural vegetation as well as cropland and pasture/rangeland; the simulated exchange of greenhouse gases between the land and atmosphere feeds back into IMOGEN's predictions. LPJ-GUESS also produces potential vegetation yields for irrigated vs. rainfed crops under three levels of nitrogen fertilizer addition. PLUMv2 combines these potential yields with endogenous demand and agricultural commodity price to calculate an optimal set of land use distributions and management strategies across the world for the next five years of simulation, based on socio-economic scenario data. These land uses are then fed back into LPJ-GUESS, and the cycle of climate, greenhouse gas emissions, crop yields, and land-use change continues. The globally gridded nature of the
Characteristics for Software Optimization Projects
Iulian NITESCU
2008-01-01
Full Text Available The increasing of the software systems complexity imposes the identification and implementation of some methods and techniques in order to manage it. The software optimization project is a way in which the software complexity is controlled. The software optimization project must face to the organization need to earn profit. The software optimization project is an integrated part of the application cycle because share same resources, depends on other stages and influences next phases. The optimization project has some particularities because it works on an finished product around its quality. The process is quality and performance oriented and it assumes that the product life cycle is almost finished.
The Optimal Income Taxation of Couples
Kleven, Henrik Jacobsen; Kreiner, Claus Thustrup; Satz, Emmanuel
This paper analyzes the optimal income tax treatment of couples. Each couple is modelled as a single rational economic agent supplying labor along two dimensions: primary and secondary earnings. We consider fully general joint income tax systems. Separate taxation is never optimal if social welfare...
Optimizing Chromatic Coupling Measurement in the LHC
Persson, Tobias
2016-01-01
Optimizing chromatic coupling measurement in the LHC Chromatic coupling introduces a dependency of transverse coupling with energy. LHC is equipped with skew sextupoles to compensate the possible adverse effects of chromatic coupling. In 2012 a beam-based correction was calculated and applied successfully for the fist time. However, the method used to reconstruct the chromatic coupling was dependent on stable tunes and equal chromaticities between the horizontal and vertical planes. In this article an improved method to calculate the chromatic coupling without these constraints is presented.
The Optimal Income Taxation of Couples
Kleven, Henrik Jacobsen; Kreiner, Claus Thustrup; Satz, Emmanuel
This paper analyzes the optimal income tax treatment of couples. Each couple is modelled as a single rational economic agent supplying labor along two dimensions: primary and secondary earnings. We consider fully general joint income tax systems. Separate taxation is never optimal if social welfare...... depends on total couple incomes. In a model where secondary earners make only a binary work decision (work or not work), we demonstrate that the marginal tax rate of the primary earner is lower when the spouse works. As a result, the tax distortion on the secondary earner decreases with the earnings...... of the primary earner and actually vanishes to zero asymptotically. Such negative jointness is optimal because redistribution from two-earner toward one-earner couples is more valuable when primary earner income is lower. We also consider a model where both spouses display intensive labor supply responses...
Optimized ground coupled heat pump mechanical package
Catan, M.A.
1987-01-01
This project addresses the question of how well a ground coupled heat pump system could perform with a heat pump which was designed specifically for such systems operating in a northern climate. Conventionally, systems are designed around water source heat pumps which are not designed for ground coupled heat pump application. The objective of the project is to minimize the life cycle cost for a ground coupled system given the freedom to design the heat pump and the ground coil in concert. In order to achieve this objective a number of modeling tools were developed which will likely be of interest in their own right.
Convex Optimization without Projection Steps
Jaggi, Martin
2011-01-01
We study the general problem of minimizing a convex function over a compact convex domain. We will investigate a simple iterative approximation algorithm that does not need projection steps in order to stay inside the optimization domain. Instead of a projection step, the linearized problem defined by a current subgradient is solved, which gives a step direction that will naturally stay in the domain. The approach generalizes the sparse greedy algorithm of Clarkson (and the low-rank SDP solver by Hazan) to arbitrary convex domains, and to using subgradients for the case of non-differentiable convex functions. Analogously, we give a convergence proof guaranteeing {\\epsilon}-small duality gap after O(1/{\\epsilon}) iterations. The framework allows us understand the sparsity of approximate solutions for any l1-regularized convex optimization problem, expressed as a function of the approximation quality. We obtain matching upper and lower bounds of {\\Theta}(1/{\\epsilon}) for the sparsity for l1-problems. The same ...
The Optimal Income Taxation of Couples
Kleven, Henrik Jacobsen; Kreiner, Claus Thustrup; Saez, Emmanuel
2009-01-01
This paper analyzes the general nonlinear optimal income tax for couples, a multidimensional screening problem. Each couple consists of a primary earner who always participates in the labor market, but makes an hours-of-work choice, and a secondary earner who chooses whether or not to work...... calibrated microsimulations for the United Kingdom showing that decreasing tax rates on secondary earnings is quantitatively significant and consistent with actual income tax and transfer programs....
Optimizing Vibrational Coordinates To Modulate Intermode Coupling.
Zimmerman, Paul M; Smereka, Peter
2016-04-12
The choice of coordinate system strongly affects the convergence properties of vibrational structure computations. Two methods for efficient generation of improved vibrational coordinates are presented and justified by analysis of a model anharmonic two-mode Hessian and numerical computations on polyatomic molecules. To produce optimal coordinates, metrics which quantify off-diagonal couplings over a grid of Hessian matrices are minimized through unitary rotations of the vibrational basis. The first proposed metric minimizes the total squared off-diagonal coupling, and the second minimizes the total squared change in off-diagonal coupling. In this procedure certain anharmonic modes tend to localize, for example X-H stretches. The proposed methods do not rely on prior fitting of the potential energy, vibrational structure computations, or localization metrics, so they are unique from previous vibrational coordinate generation algorithms and are generally applicable to polyatomic molecules. Fitting the potential to the approximate n-mode representation in the optimized bases for all-trans polyenes shows that off-diagonal anharmonic couplings are substantially reduced by the new choices of coordinate system. Convergence of vibrational energies is examined in detail for ethylene, and it is shown that coupling-optimized modes converge in vibrational configuration interaction computations to within 1 cm(-1) using only 3-mode couplings, where normal modes require 4-mode couplings for convergence. Comparison of the vibrational configuration interaction convergence with respect to excitation level for the two proposed metrics shows that minimization of the total off-diagonal coupling is most effective for low-cost vibrational structure computations.
STUDY OF TOPOLOGY OPTIMIZATION FOR THERMO-STRUCTURAL COUPLING FIELD
Zuo Kongtian; Qian Qin; Zhao Yudong; Chen Liping
2005-01-01
A number of critical problems of topology optimization concerning the thermostructural coupling field are studied at length. The governing equations and topology optimization model for the thermal-structural coupling field are derived, with an adjoint method for sensitivity analysis of the thermo-structural coupling field proposed. The optimization algorithm for coupling field topology optimization is investigated and a flowchart of coupling field topology optimization presented. The theory and algorithms are implemented and verified by two numerical examples.
Optimized ground coupled heat pump design: Phase 1, Final report
Andrews, J.W.; Catan, M.; Le Doux, P.; Metz, P.D.; Saunders, J.H.
1985-10-01
This report describes the first phase of a project to design a water-to-air heat pump optimized for ground coupling applications. The project is being conducted jointly by Brookhaven National Laboratory (BNL), Oak Ridge National Laboratory (ORNL), and an industrial partner to be selected via a competitive procurement. In the completion of Phase I, three major tasks were completed. First, based on experimental work performed at BNL, water-refrigerant heat exchanger models were developed for incorporation into the ORNL heat pump optimization program. Next, a procedure was developed to generate correlations between heat pump entering fluid temperature and load. The correlations, called ''Source Temperature/Load Maps'', will tell the optimization program how many hours/season the heat pump will operate with any pair of values for these quantities. This report discusses these first two tasks within Phase I.
Coupled multiscale simulation and optimization in nanoelectronics
2015-01-01
Designing complex integrated circuits relies heavily on mathematical methods and calls for suitable simulation and optimization tools. The current design approach involves simulations and optimizations in different physical domains (device, circuit, thermal, electromagnetic) and in a range of electrical engineering disciplines (logic, timing, power, crosstalk, signal integrity, system functionality). COMSON was a Marie Curie Research Training Network created to meet these new scientific and training challenges by (a) developing new descriptive models that take these mutual dependencies into account, (b) combining these models with existing circuit descriptions in new simulation strategies, and (c) developing new optimization techniques that will accommodate new designs. The book presents the main project results in the fields of PDAE modeling and simulation, model order reduction techniques and optimization, based on merging the know-how of three major European semiconductor companies with the combined expe...
Optimization of a ground coupled heat pump
Baxter, V.D.; Catan, M.A.
1984-01-01
A cooperative analytical project has optimized a horizontal ground coil heat pump system for the Pittsburgh climate. This is the first step in the exploration of several advanced designs including various ground coil devices and advanced heat pump components. The project made use of new and existing design tools to simulate system performance and determine first cost. The system life cycle cost was minimized while constraining the system to meet the design day cooling load using a function minimizing program. Among the system parameters considered were: air-to-refrigerant frontal area, air-to-refrigerant fin pitch, air-to-refrigerant air flowrate, compressor displacement, liquid-to-refrigerant coil length, liquid-to-refrigerant coil diameter, ground coil fluid flowrate, ground coil length, and ground coil depth.
Integrated Multidisciplinary Optimization Objects Project
National Aeronautics and Space Administration — M4 Engineering proposes to implement physics-based, multidisciplinary analysis and optimization objects that will be integrated into a Python, open-source framework...
Framework for Autonomous Optimization Project
National Aeronautics and Space Administration — Phoenix Integration and MIT propose to create a novel autonomous optimization tool and application programming interface (API). The API will demonstrate the ability...
Optimized Projection Matrix for Compressive Sensing
Jianping Xu
2010-01-01
Full Text Available Compressive sensing (CS is mainly concerned with low-coherence pairs, since the number of samples needed to recover the signal is proportional to the mutual coherence between projection matrix and sparsifying matrix. Until now, papers on CS always assume the projection matrix to be a random matrix. In this paper, aiming at minimizing the mutual coherence, a method is proposed to optimize the projection matrix. This method is based on equiangular tight frame (ETF design because an ETF has minimum coherence. It is impossible to solve the problem exactly because of the complexity. Therefore, an alternating minimization type method is used to find a feasible solution. The optimally designed projection matrix can further reduce the necessary number of samples for recovery or improve the recovery accuracy. The proposed method demonstrates better performance than conventional optimization methods, which brings benefits to both basis pursuit and orthogonal matching pursuit.
REPNET: project scheduling and workflow optimization for Construction Projects
Marco Alvise Bragadin
2013-10-01
Full Text Available Project planning and control are core processes for construction management. In practice project planning is achieved by network - based techniques like Precedence Diagramming Method (PDM.Indeed many researchers and practitioners claims that networking techniques as such do not provide a suitable model for construction projects. Construction process modeling should incorporate for specific features of resource flows through project activities. So an improved resource scheduling method for construction is developed, called REPNET, based on a precedence network plotted on a resource–space chart and presented with a flow-line chart. The heuristics of REPNET are used to carry out resource timing while optimizing processes flows and resource usage. The method has been tested on a sample project.
Optimized ground coupled heat pump mechanical package
Catan, M.A.
1984-01-01
The system which was optimized was a horizontal earth coil in a given house in the Pittsburgh area. The types of components used in the heat pump are essentially conventional. The method of this study is derived from one used to optimize an air-source heat pump for operation at standard steady state conditions. A computer model, created at Oak Ridge National Laboratory (ORNL), is used to predict heat pump performance for specified configuration and operating conditions. A predetermined set of design parameters is automatically altered by a constrained minimization program (a Numerical Algorithms Group library routine hereafter referred to as the optimizer) to find the combination for which the highest COP is predicted by the heat pump model. In the present study, the set of parameters to be varied include some pertaining to the ground coil as well as some pertaining to the heat pump. The optimizer, in this case, pursues a minimum life cycle cost which is calculated using the heat pump model, a ground coil model (called FTECM for Fast Transient Earth Coil model), and a parameterized cost model. The flow chart shows how the optimizer interacts with these programs to minimize life cycle cost.
Aeroelastic coupling in sonic boom optimization of a supersonic aircraft
Vázquez, Mariano; Dervieux, Alain; Koobus, Bruno
2003-01-01
In this paper, we consider a multi-disciplinary optimization problem where the initial shape of a wing is sought in order to cope, after elastic deformation by the flow, with some optimality conditions. We propose a medium-strong coupling which allows to consider different softwares communicating a small number of times. Applications to the optimization of the AGARD Wing 445.6 and a flexible supersonic aircraft wing are presented.
Parameters optimization for magnetic resonance coupling wireless power transmission.
Li, Changsheng; Zhang, He; Jiang, Xiaohua
2014-01-01
Taking maximum power transmission and power stable transmission as research objectives, optimal design for the wireless power transmission system based on magnetic resonance coupling is carried out in this paper. Firstly, based on the mutual coupling model, mathematical expressions of optimal coupling coefficients for the maximum power transmission target are deduced. Whereafter, methods of enhancing power transmission stability based on parameters optimal design are investigated. It is found that the sensitivity of the load power to the transmission parameters can be reduced and the power transmission stability can be enhanced by improving the system resonance frequency or coupling coefficient between the driving/pick-up coil and the transmission/receiving coil. Experiment results are well conformed to the theoretical analysis conclusions.
Parameters Optimization for Magnetic Resonance Coupling Wireless Power Transmission
Changsheng Li
2014-01-01
Full Text Available Taking maximum power transmission and power stable transmission as research objectives, optimal design for the wireless power transmission system based on magnetic resonance coupling is carried out in this paper. Firstly, based on the mutual coupling model, mathematical expressions of optimal coupling coefficients for the maximum power transmission target are deduced. Whereafter, methods of enhancing power transmission stability based on parameters optimal design are investigated. It is found that the sensitivity of the load power to the transmission parameters can be reduced and the power transmission stability can be enhanced by improving the system resonance frequency or coupling coefficient between the driving/pick-up coil and the transmission/receiving coil. Experiment results are well conformed to the theoretical analysis conclusions.
Superconducting Resonant Inductive Power Coupling Project
National Aeronautics and Space Administration — The proposed effort will develop a technology to wirelessly and efficiently transfer power over hundreds of meters via resonant inductive coupling. The key...
Optimal design of a composite bellows coupling using a structural optimization
Sedlacek, Frantisek; Bernardin, Petr; Lasova, Vaclava
2017-05-01
This paper deals with a flexible bellows coupling from composite materials that may be used as a replacement for some conventional rigid steel couplings. A geometry optimization was done in connection with structural analysis to find the optimal geometry and layout of the individual plies of the laminate of the composite bellows coupling. These numerical simulations were created with NX Nastran solver in Siemens Simcenter 11. An advanced FE model was used to verify the model according to the geometry optimization. A maximum stress strength criterion was carried out to evaluate the strength of the composite structure.
Slot Coupled Patch Array Antenna Technology Project
National Aeronautics and Space Administration — The proposed project is an antenna array whose beam is controlled digitally. The Phase 1 effort will assess the method needed to achieve the gain, bandwidth, and...
Measurement and Optimization of Local Coupling from RHIC BPM Data
Calaga, Rama; Bai, Mei; Fischer, Wolfram; Franchi, Andrea; Tomas, Rogelio
2005-01-01
Global coupling in RHIC is routinely corrected by using three skew quadrupole families to minimize the tune split. In this paper we aim to re-optimize the coupling at top energy by minimizing resonance driving terms and the C-matrix in two steps: 1. Find the best configuration of the three skew quadrupole families and 2. Identify locations with coupling sources by inspection of the driving terms and the C-matrix around the ring. The measurements of resonance terms and C-matrix are presented.
Projective synchronization of chaotic systems with bidirectional nonlinear coupling
Mohammada Ali Khan; Swarup Poria
2013-09-01
This paper presents a new scheme for constructing bidirectional nonlinear coupled chaotic systems which synchronize projectively. Conditions necessary for projective synchronization (PS) of two bidirectionally coupled chaotic systems are derived using Lyapunov stability theory. The proposed PS scheme is discussed by taking as examples the so-called unified chaotic model, the Lorenz–Stenflo system and the nonautonomous chaotic Van der Pol oscillator. Numerical simulation results are presented to show the efficiency of the proposed synchronization scheme.
Coupled Low-thrust Trajectory and System Optimization via Multi-Objective Hybrid Optimal Control
Vavrina, Matthew A.; Englander, Jacob Aldo; Ghosh, Alexander R.
2015-01-01
The optimization of low-thrust trajectories is tightly coupled with the spacecraft hardware. Trading trajectory characteristics with system parameters ton identify viable solutions and determine mission sensitivities across discrete hardware configurations is labor intensive. Local independent optimization runs can sample the design space, but a global exploration that resolves the relationships between the system variables across multiple objectives enables a full mapping of the optimal solution space. A multi-objective, hybrid optimal control algorithm is formulated using a multi-objective genetic algorithm as an outer loop systems optimizer around a global trajectory optimizer. The coupled problem is solved simultaneously to generate Pareto-optimal solutions in a single execution. The automated approach is demonstrated on two boulder return missions.
Optimal piezo-electro-mechanical coupling to control plate vibrations
Alessandroni, S; Frezza, F
2010-01-01
A new way of coupling electrical and mechanical waves, using piezoelectric effect, is presented here. Since the energy exchange between two systems supporting wave propagation is maximum when their evolution is governed by similar equations, hence, an optimal electromechanical coupling is obtained by designing an electric network which is "analog" to the mechanical structure to be controlled. In this paper, we exploit this idea to enhance the coupling, between a Kirchhoff-Love plate and one possible synthesis of its circuital analog, as obtained by means of a set of piezoelectric actuators uniformly distributed upon the plate. It is shown how this approach allows for an optimal energy exchange between the mechanic and the electric forms independent of the modal evolution of the structure. Moreover, we show how an efficient electric dissipation of the mechanical energy can be obtained adding dissipative elements in the electric network.
Optimization of Internal Thermally Coupled Distillation Columns of Nonideal Mixture
刘兴高; 徐用懋; 钱积新
2001-01-01
Internal thermally coupled distillation column(ITCDIC) is a frontier in energy saving distillation research. In this paper, the optimal assessment on the energy saving and the operating cost for ITCDIC of nonideal mixture is explored. An evaluating method is proposed, and the pertinent optimization model is then derived. The ethanol-water system is studied as an illustrative example. The optimization results show that the maximum energy saving in ITCDIC process is about 35% and the maximum operating cost saving in ITCDIC process is about 30%,as compared with a conventional distillation column(CDIC) under the minimum reflux ratio operating; the optimal operating pressure of the rectifying section is found to be around 0.25 MPa; the effects of the feed composition,operating pressure and the heat transfer rate on operation are also found and analyzed. It is revealed that ITCDIC process possesses high energy saving potential and promising economical prospect.
On Shape Optimization for an Evolution Coupled System
Leugering, G., E-mail: leugering@am.uni-erlangen.de [University of Erlangen Nuremberg, Department of Mathematics (Germany); Novotny, A. A., E-mail: novotny@lncc.br; Perla Menzala, G., E-mail: perla@lncc.br [Coordenacao de Matematica Aplicada e Computacional, Laboratorio Nacional de Computacao Cientifica LNCC/MCT (Brazil); Sokolowski, J., E-mail: Jan.Sokolowski@iecn.u-nancy.fr [Institut Elie Cartan, UMR 7502 (Nancy Universite, CNRS, INRIA), Laboratoire de Mathematiques, Universite Henri Poincare Nancy I (France)
2011-12-15
A shape optimization problem in three spatial dimensions for an elasto-dynamic piezoelectric body coupled to an acoustic chamber is introduced. Well-posedness of the problem is established and first order necessary optimality conditions are derived in the framework of the boundary variation technique. In particular, the existence of the shape gradient for an integral shape functional is obtained, as well as its regularity, sufficient for applications e.g. in modern loudspeaker technologies. The shape gradients are given by functions supported on the moving boundaries. The paper extends results obtained by the authors in (Math. Methods Appl. Sci. 33(17):2118-2131, 2010) where a similar problem was treated without acoustic coupling.
Software Project Scheduling Management by Particle Swarm Optimization
Dinesh B. Hanchate
2014-12-01
Full Text Available PSO (Particle Swarm Optimization is, like GA, a heuristic global optimization method based on swarm intelligence. In this paper, we present a particle swarm optimization algorithm to solve software project scheduling problem. PSO itself inherits very efficient local search method to find the near optimal and best-known solutions for all instances given as inputs required for SPSM (Software Project Scheduling Management. At last, this paper imparts PSO and research situation with SPSM. The effect of PSO parameter on project cost and time is studied and some better results in terms of minimum SCE (Software Cost Estimation and time as compared to GA and ACO are obtained.
A Metaheuristic Approach for IT Projects Portfolio Optimization
Pushkar, Shashank; Mishra, Akhileshwar
2010-01-01
Optimal selection of interdependent IT Projects for implementation in multi periods has been challenging in the framework of real option valuation. This paper presents a mathematical optimization model for multi-stage portfolio of IT projects. The model optimizes the value of the portfolio within a given budgetary and sequencing constraints for each period. These sequencing constraints are due to time wise interdependencies among projects. A Metaheuristic approach is well suited for solving this kind of a problem definition and in this paper a genetic algorithm model has been proposed for the solution. This optimization model and solution approach can help IT managers taking optimal funding decision for projects prioritization in multiple sequential periods. The model also gives flexibility to the managers to generate alternative portfolio by changing the maximum and minimum number of projects to be implemented in each sequential period.
Light weakly coupled axial forces: models, constraints, and projections
Kahn, Yonatan; Krnjaic, Gordan; Mishra-Sharma, Siddharth; Tait, Tim M. P.
2017-05-01
We investigate the landscape of constraints on MeV-GeV scale, hidden U(1) forces with nonzero axial-vector couplings to Standard Model fermions. While the purely vector-coupled dark photon, which may arise from kinetic mixing, is a well-motivated scenario, several MeV-scale anomalies motivate a theory with axial couplings which can be UV-completed consistent with Standard Model gauge invariance. Moreover, existing constraints on dark photons depend on products of various combinations of axial and vector couplings, making it difficult to isolate the effects of axial couplings for particular flavors of SM fermions. We present a representative renormalizable, UV-complete model of a dark photon with adjustable axial and vector couplings, discuss its general features, and show how some UV constraints may be relaxed in a model with nonrenormalizable Yukawa couplings at the expense of fine-tuning. We survey the existing parameter space and the projected reach of planned experiments, briefly commenting on the relevance of the allowed parameter space to low-energy anomalies in π0 and 8Be∗ decay.
Light Weakly Coupled Axial Forces: Models, Constraints, and Projections
Kahn, Yonatan; Mishra-Sharma, Siddharth; Tait, Tim M P
2016-01-01
We investigate the landscape of constraints on MeV-GeV scale, hidden U(1) forces with nonzero axial-vector couplings to Standard Model fermions. While the purely vector-coupled dark photon, which may arise from kinetic mixing, is a well-motivated scenario, several MeV-scale anomalies motivate a theory with axial couplings which can be UV-completed consistent with Standard Model gauge invariance. Moreover, existing constraints on dark photons depend on products of various combinations of axial and vector couplings, making it difficult to isolate the effects of axial couplings for particular flavors of SM fermions. We present a representative renormalizable, UV-complete model of a dark photon with adjustable axial and vector couplings, discuss its general features, and show how some UV constraints may be relaxed in a model with nonrenormalizable Yukawa couplings at the expense of fine-tuning. We survey the existing parameter space and the projected reach of planned experiments, briefly commenting on the relevan...
Light Weakly Coupled Axial Forces: Models, Constraints, and Projections
Kahn, Yonatan [Princeton U.; Krnjaic, Gordan [Fermilab; Mishra-Sharma, Siddharth [Princeton U.; Tait, Tim P. [UC, Irvine
2016-09-28
We investigate the landscape of constraints on MeV-GeV scale, hidden U(1) forces with nonzero axial-vector couplings to Standard Model fermions. While the purely vector-coupled dark photon, which may arise from kinetic mixing, is a well-motivated scenario, several MeV-scale anomalies motivate a theory with axial couplings which can be UV-completed consistent with Standard Model gauge invariance. Moreover, existing constraints on dark photons depend on products of various combinations of axial and vector couplings, making it difficult to isolate the effects of axial couplings for particular flavors of SM fermions. We present a representative renormalizable, UV-complete model of a dark photon with adjustable axial and vector couplings, discuss its general features, and show how some UV constraints may be relaxed in a model with nonrenormalizable Yukawa couplings at the expense of fine-tuning. We survey the existing parameter space and the projected reach of planned experiments, briefly commenting on the relevance of the allowed parameter space to low-energy anomalies in pi^0 and 8-Be* decay.
Model reduction for optimization of structural-acoustic coupling problems
Creixell Mediante, Ester; Jensen, Jakob Søndergaard; Brunskog, Jonas;
2016-01-01
, which becomes highly time consuming since many iterations may be required. The use of model reduction techniques to speed up the computations is studied in this work. The Component Mode Synthesis (CMS) method and the Multi-Model Reduction (MMR) method are adapted for problems with structure......Fully coupled structural-acoustic models of complex systems, such as those used in the hearing aid field, may have several hundreds of thousands of nodes. When there is a strong structure-acoustic interaction, performing optimization on one part requires the complete model to be taken into account...
PROJECT SCHEDULING OPTIMIZATION IN ELECTRICAL POWER UTILITIES
Cleber Mira
2015-08-01
Full Text Available The problem of choosing from a set of projects which ones should be executed and whenthey should start, depending on several restrictions involving project costs, risks, limited resources, dependencies among projects, and aiming at different, even conflicting, goals is known as the project portfolio selection (PPS problem. We study a particular version of the PPS problem stemming from the operation of a real power generation company. It includes distinct categories of resources, intricate dependencies between projects, which are especially important for the management of power plants, and the prevention of risks. We present an algorithm based on the GRASP meta-heuristic for finding better results thanmanual solutions produced by specialists. The algorithm yielded solutions that decreased the risk by 47%, as measured by the company's standard methodology.
Optimization of Weight Including Damage Scenarios Project
National Aeronautics and Space Administration — M4 Engineering proposes to develop a method of incorporating several analyses into one process and then optimizing the structure. This method will allow for...
Loaded Gelled Bipropellants for Optimized Performance Project
National Aeronautics and Space Administration — The focus of this program is the development and validation of formulations, and development methodologies, for optimizing high-performance particulate-loaded...
Synthetic Imaging Maneuver Optimization (SIMO) Project
National Aeronautics and Space Administration — Aurora Flight Sciences (AFS), in collaboration with the MIT Space Systems Laboratory (MIT-SSL), proposed the Synthetic Imaging Maneuver Optimization (SIMO) program...
Parallel Nonlinear Optimization for Astrodynamic Navigation Project
National Aeronautics and Space Administration — CU Aerospace proposes the development of a new parallel nonlinear program (NLP) solver software package. NLPs allow the solution of complex optimization problems,...
Discrete Geometry Toolkit for Shape Optimization Project
National Aeronautics and Space Administration — Simulation-based design optimization has been steadily maturing over the past two decades, but not without its own unique and persistent challenges. The proposed...
Discrete Geometry Toolkit for Shape Optimization Project
National Aeronautics and Space Administration — Simulation-based design optimization has been steadily maturing over the past two decades, but not without its own unique and persistent challenges. The proposed...
DOE Project 353: TAMS Prototype and production coupling alignment units
Field, K.V.
1996-02-01
TAMS is an electronic measurement system used to determine the alignment of turbine-generator shafts at the coupling interface. The displacement transducer is a strain gage based sensor mounted in a portable probe. The measurement system was experiencing zero input drift and temperature induced drift. This project endeavored to determine the source of these problems and to revise a unit to be returned to a customer, Baltimore Gas and Electric (BGE), within a period of five weeks.
2010 Military Family Life Project (MFLP) - Couples: Tabulations of Responses
2013-08-31
care home, preschool , after-school program)? Number of child care arrangements 2010 Military Family Life Project: Couples DMDC 119 67. [Ask if...officials contributing to the development of this survey included Cathy Flynn and Yuko Whitestone (Military Community and Family Policy). DMDC’s Survey...Design, Analysis & Operations Branch, under the guidance of Paul Rosenfeld, Branch Chief, is responsible for the development of questionnaires used
An optimized ground-coupled heat pump system design for northern climate applications
Catan, M.A.; Baxter, V.D.
1985-01-01
This paper addresses the question of the performance of a ground coupled heat pump (GCHP) system with a water-source heat pump package designed expressly for such systems operating in a northern climate. The project objective was to minimize the life-cycle cost of a GCHP system by optimizing the design of both the heat pump package and the group coil in concert. In order to achieve this objective, a number of modelling tools were developed to analyze the heat pump's performance and cost, and the ground coil's performance.
Topology optimization for optical projection lithography with manufacturing uncertainties
Zhou, Mingdong; Lazarov, Boyan Stefanov; Sigmund, Ole
2014-01-01
This article presents a topology optimization approach for micro-and nano-devices fabricated by optical projection lithography. Incorporating the photolithography process and the manufacturing uncertainties into the topology optimization process results in a binary mask that can be sent directly...
Partial Oblique Projection Learning for Optimal Generalization
LIU Benyong; ZHANG Jing
2004-01-01
In practice,it is necessary to implement an incremental and active learning for a learning method.In terms of such implementation,this paper shows that the previously discussed S-L projection learning is inappropriate to constructing a family of projection learning,and proposes a new version called partial oblique projection (POP) learning.In POP learning,a function space is decomposed into two complementary subspaces,so that functions belonging to one of the subspaces can be completely estimated in noiseless case;while in noisy case,the dispersions are set to be the smallest.In addition,a general form of POP learning is presented and the results of a simulation are given.
Extension-twist coupling optimization in composite rotor blades
Ozbay, Serkan
2005-07-01
For optimal rotor performance in a tiltrotor aircraft the difference in the inflow and the rotor speeds between the hover and cruise flight modes suggests different blade twist and chord distributions. The blade twist rates in current tiltrotor applications are defined based upon a compromise between the figure of merit in hover and propeller efficiency in airplane mode. However, when each operation mode is considered separately the optimum blade distributions are found to be considerably different. Passive blade twist control, which uses the inherent variation in centrifugal forces on a rotor blade to achieve optimum blade twist distributions in each flight mode through the use of extension-twist coupled composite rotor blades, has been considered for performance improvement of tiltrotor aircraft over the last two decades. The challenge for this concept is to achieve the desired twisting deformations in the rotor blade without altering the aeroelastic characteristics of the vehicle. A concept referred to as the sliding mass concept is proposed in this work in order to increase the twist change with rotor speed for a closed-cell composite rotor blade cross-section to practical levels for performance improvement in a tiltrotor aircraft. The concept is based on load path changes for the centrifugal forces by utilizing non-structural masses readily available on a conventional blade, such as the leading edge balancing mass. A multilevel optimization technique based on the simulated annealing method is applied to improve the performance of the XV15 tiltrotor aircraft. A cross-sectional analysis tool, VABS together with a multibody dynamics code, DYMORE are integrated into the optimization process. The optimization results revealed significant improvements in the power requirement in hover while preserving cruise efficiency. It is also shown that about 21% of the improvement is provided through the sliding mass concept pointing to the additional flexibility the concept
Overview of the Coupled Model Intercomparison Project (CMIP)
Meehl, G A; Covey, C; McAvaney, B; Latif, M; Stouffer, R J
2004-08-05
The Coupled Model Intercomparison Project (CMIP) is designed to allow study and intercomparison of multi-model simulations of present-day and future climate. The latter are represented by idealized forcing of compounded 1% per year CO2 increase to the time of CO2 doubling near year 70 in simulations with global coupled models that contain, typically, components representing atmosphere, ocean, sea ice and land surface. Results from CMIP diagnostic subprojects were presented at the Second CMIP Workshop held at the Max Planck Institute for Meteorology in Hamburg, Germany, in September, 2003. Significant progress in diagnosing and understanding results from global coupled models has been made since the First CMIP Workshop in Melbourne, Australia in 1998. For example, the issue of flux adjustment is slowly fading as more and more models obtain stable multi-century surface climates without them. El Nino variability, usually about half the observed amplitude in the previous generation of coupled models, is now more accurately simulated in the present generation of global coupled models, though there are still biases in simulating the patterns of maximum variability. Typical resolutions of atmospheric component models contained in coupled models is now usually around 2.5 degrees latitude-longitude, with the ocean components often having about twice the atmospheric model resolution, with even higher resolution in the equatorial tropics. Some new-generation coupled models have atmospheric model resolutions of around 1.5 degrees latitude-longitude. Modeling groups now routinely run the CMIP control and 1% CO2 simulations in addition to 20th and 21st century climate simulations with a variety of forcings (e.g. volcanoes, solar variability, anthropogenic sulfate aerosols, ozone, and greenhouse gases (GHGs), with the anthropogenic forcings for future climate as well). However, persistent systematic errors noted in previous generations of global coupled models still are present
Multi-objective genetic optimization of linear construction projects
Fatma A. Agrama
2012-08-01
Full Text Available In the real world, the majority cases of optimization problems, met by engineers, are composed of several conflicting objectives. This paper presents an approach for a multi-objective optimization model for scheduling linear construction projects. Linear construction projects have many identical units wherein activities repeat from one unit to another. Highway, pipeline, and tunnels are good examples that exhibit repetitive characteristics. These projects represent a large portion of the construction industry. The present model enables construction planners to generate optimal/near-optimal construction plans that minimize project duration, total work interruptions, and total number of crews. Each of these plans identifies, from a set of feasible alternatives, optimal crew synchronization for each activity and activity interruptions at each unit. This model satisfies the following aspects: (1 it is based on the line of balance technique; (2 it considers non-serial typical activities networks with finish–start relationship and both lag or overlap time between activities is allowed; (3 it utilizes a multi-objective genetic algorithms approach; (4 it is developed as a spreadsheet template that is easy to use. Details of the model with visual charts are presented. An application example is analyzed to illustrate the use of the model and demonstrate its capabilities in optimizing the scheduling of linear construction projects.
Visual Dynamic Simulation and Optimization of Zhangjiuhe Diversion Project
ZHONG Denghua; LIU Jianmin; XIONG Kaizhi; FU Jinqiang
2008-01-01
With the aim of visualizing the real-time simulation calculation of water delivery system (WDS), a structural drawing-oriented (SDO) simulation technique was presented, and applied to Zhangjiuhe Diversion Project, which is a long-distance water delivery system constructed for drawing water from the Zhangjiuhe River to Kunming city. Taking SIMULINK software as simulating platform, the technique established a visual dynamic simulation model for the system. The simulation procedure of the system was simplified, and the efficiency of modeling was also enhanced according to the modularization and reutilization of the simulation program. Furthermore, a selfoptimization model was presented. Based on the digital simulation models, the on line controlled optimization link was added, and the input data can be continually optimized according to the feedback information of simulating output. The system was thus optimized automatically. Built upon MATLAB software, simulation optimization of the Zhangjiuhe Diversion Project was achieved, which provides a new way for the research of optimal operation of WDS.
Tang Zhili; Dong Jun
2009-01-01
complete and complete decisions of the leader and followers respectively. Several design examples illustrate the efficiency of the coupling algorithms for multi-criterion aerodynamic design optimization problems.
WANG Jia-song; ZHAO Bao-qing; YE Chun; YANG De-qing; HUANG Zhen
2006-01-01
Optimizing the layout of the urban street canyon to achieve the maximum environmental benefits should become a new idea for modern urban street design and planning. This paper aims to find out the optimized street canyon from a viewpoint of environmental protection by using the two-dimensional numerical simulation model with the turbulence model, coupling with the mathematical optimization method. The total pollutant concentration within and at top of the specific street canyons was taken as the objective function, and the height of one side of the canyon as the constrained condition. A nonlinearly improved constrained variable metric solver was used. The effect of the height of the leeward building and windward building on the integrated pollutant dispersion was studied to achieve the most beneficial configuration of the urban geometry. The optimization of layout for an asymmetrical street canyon was obtained. It is further found that the step-down street canyon with a large height difference is generally a good layout favoring to reduce the concentration accumulation in the street canyon.
Character Projection Mask Set Optimization for Enhancing Throughput of MCC Projection Systems
Sugihara, Makoto; Matsunaga, Yusuke; Murakami, Kazuaki
Character projection (CP) lithography is utilized for maskless lithography and is a potential for the future photomask manufacture because it can project ICs much faster than point beam projection or variable-shaped beam (VSB) projection. In this paper, we first present a projection mask set development methodology for multi-column-cell (MCC) systems, in which column-cells can project patterns in parallel with the CP and VSB lithographies. Next, we present an INLP (integer nonlinear programming) model as well as an ILP (integer linear programming) model for optimizing a CP mask set of an MCC projection system so that projection time is reduced. The experimental results show that our optimization has achieved 33.4% less projection time in the best case than a naive CP mask development approach. The experimental results indicate that our CP mask set optimization method has virtually increased cell pattern objects on CP masks and has decreased VSB projection so that it has achieved higher projection throughput than just parallelizing two column-cells with conventional CP masks.
An Optimized Analogy-Based Project Effort Estimation
Mohammad Azzeh
2014-05-01
Full Text Available despite the predictive performance of Analogy-Based Estimation (ABE in generating better effort estimates, there is no consensus on: (1 how to predetermine the appropriate number of analogies, (2 which adjustment technique produces better estimates. Yet, there is no prior works attempted to optimize both number of analogies and feature distance weights for each test project. Perhaps rather than using fixed number, it is better to optimize this value for each project individually and then adjust the retrieved analogies by optimizing and approximating complex relationships between features and reflects that approximation on the final estimate. The Artificial Bees Algorithm is utilized to find, for each test project, the appropriate number of closest projects and features distance weights that is used to adjust those analogies’ efforts. The proposed technique has been applied and validated to 8 publically datasets from PROMISE repository. Results obtained show that: (1 the predictive performance of ABE has noticeably been improved, (2 the number of analogies was remarkably variable for each test project. While there are many techniques to adjust ABE, Using optimization algorithm provides two solutions in one technique and appeared useful for datasets with complex structure.
Projections onto the Pareto surface in multicriteria radiation therapy optimization
Bokrantz, Rasmus, E-mail: bokrantz@kth.se, E-mail: rasmus.bokrantz@raysearchlabs.com [Optimization and Systems Theory, Department of Mathematics, KTH Royal Institute of Technology, Stockholm SE-100 44, Sweden and RaySearch Laboratories, Sveavägen 44, Stockholm SE-103 65 (Sweden); Miettinen, Kaisa [Optimization and Systems Theory, Department of Mathematics, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden and University of Jyvaskyla, Department of Mathematical Information Technology, FI-400 14 University of Jyvaskyla (Finland)
2015-10-15
Purpose: To eliminate or reduce the error to Pareto optimality that arises in Pareto surface navigation when the Pareto surface is approximated by a small number of plans. Methods: The authors propose to project the navigated plan onto the Pareto surface as a postprocessing step to the navigation. The projection attempts to find a Pareto optimal plan that is at least as good as or better than the initial navigated plan with respect to all objective functions. An augmented form of projection is also suggested where dose–volume histogram constraints are used to prevent that the projection causes a violation of some clinical goal. The projections were evaluated with respect to planning for intensity modulated radiation therapy delivered by step-and-shoot and sliding window and spot-scanned intensity modulated proton therapy. Retrospective plans were generated for a prostate and a head and neck case. Results: The projections led to improved dose conformity and better sparing of organs at risk (OARs) for all three delivery techniques and both patient cases. The mean dose to OARs decreased by 3.1 Gy on average for the unconstrained form of the projection and by 2.0 Gy on average when dose–volume histogram constraints were used. No consistent improvements in target homogeneity were observed. Conclusions: There are situations when Pareto navigation leaves room for improvement in OAR sparing and dose conformity, for example, if the approximation of the Pareto surface is coarse or the problem formulation has too permissive constraints. A projection onto the Pareto surface can identify an inaccurate Pareto surface representation and, if necessary, improve the quality of the navigated plan.
Coupling between a multi-physics workflow engine and an optimization framework
Di Gallo, L.; Reux, C.; Imbeaux, F.; Artaud, J.-F.; Owsiak, M.; Saoutic, B.; Aiello, G.; Bernardi, P.; Ciraolo, G.; Bucalossi, J.; Duchateau, J.-L.; Fausser, C.; Galassi, D.; Hertout, P.; Jaboulay, J.-C.; Li-Puma, A.; Zani, L.
2016-03-01
A generic coupling method between a multi-physics workflow engine and an optimization framework is presented in this paper. The coupling architecture has been developed in order to preserve the integrity of the two frameworks. The objective is to provide the possibility to replace a framework, a workflow or an optimizer by another one without changing the whole coupling procedure or modifying the main content in each framework. The coupling is achieved by using a socket-based communication library for exchanging data between the two frameworks. Among a number of algorithms provided by optimization frameworks, Genetic Algorithms (GAs) have demonstrated their efficiency on single and multiple criteria optimization. Additionally to their robustness, GAs can handle non-valid data which may appear during the optimization. Consequently GAs work on most general cases. A parallelized framework has been developed to reduce the time spent for optimizations and evaluation of large samples. A test has shown a good scaling efficiency of this parallelized framework. This coupling method has been applied to the case of SYCOMORE (SYstem COde for MOdeling tokamak REactor) which is a system code developed in form of a modular workflow for designing magnetic fusion reactors. The coupling of SYCOMORE with the optimization platform URANIE enables design optimization along various figures of merit and constraints.
Optimizing the Prioritization of Natural Disaster Recovery Projects
2007-03-01
temperature scales such as the Fahrenheit scale. When using the AHP, a scale of measurement consists of a set of objects, a set of numbers, and a...each matrix and calculate the eigenvector of each of the developed matrices. 3. Measure the inconsistency of each of matrices using the consistency...to determine the optimal set of information systems (IS) projects for the Dubai Medical Center in the United Arabic Emirates. The system uses LINDO
Hydraulic analysis and optimization design in Guri rehabilitation project
Cheng, H.; Zhou, L. J.; Gong, L.; Wang, Z. N.; Wen, Q.; Zhao, Y. Z.; Wang, Y. L.
2016-11-01
Recently Dongfang was awarded the contract for rehabilitation of 6 units in Guri power plant, the biggest hydro power project in Venezuela. The rehabilitation includes, but not limited to, the extension of output capacity by about 50% and enhancement of efficiency level. To achieve the targets the runner and the guide vanes will be replaced by the newly optimized designs. In addition, the out-of-date stay vanes with straight plate shape will be modified into proper profiles after considering the application feasibility in field. The runner and vane profiles were optimized by using state-of-the-art flow simulation techniques. And the hydraulic performances were confirmed by the following model tests. This paper describes the flow analysis during the optimization procedure and the comparison between various technical concepts.
A Projection Neural Network for Constrained Quadratic Minimax Optimization.
Liu, Qingshan; Wang, Jun
2015-11-01
This paper presents a projection neural network described by a dynamic system for solving constrained quadratic minimax programming problems. Sufficient conditions based on a linear matrix inequality are provided for global convergence of the proposed neural network. Compared with some of the existing neural networks for quadratic minimax optimization, the proposed neural network in this paper is capable of solving more general constrained quadratic minimax optimization problems, and the designed neural network does not include any parameter. Moreover, the neural network has lower model complexities, the number of state variables of which is equal to that of the dimension of the optimization problems. The simulation results on numerical examples are discussed to demonstrate the effectiveness and characteristics of the proposed neural network.
Catan, M.A.; Baxter, V.D.
1985-01-01
This paper addresses the question of the performance of a ground coupled heat pump (GCHP) system with a water - source heat pump package designed expressly for such systems operating in a northern climate. The project objective was to minimize the life-cycle cost of a GCHP system by optimizing the design of both the heat pump package and the ground coil in concert. In order to achieve this objective, a number of modelling tools were developed or modified to analyze the heat pump's performance and cost and the ground coil's performance. The life-cycle cost of a GCHP system (water-source heat pump with a horizontal ground coil) for an 1800 ft/sup 2/ (167 m/sup 2/) house in Pittsburgh, PA, was minimized over a 7 year economic life. Simple payback for the optimized GCHP system, relative to conventional air-source heat pumps, was under 3 years. The water-source heat pump package resulting from this optimization is calculated to cost 21% more than its conventional counterpart with a heating coefficient of performance (COP) about 20% higher, and a cooling COP about 23% higher. In the GCHP system modeled, its annual energy savings are predicted to be about 11% compared to a system designed around the conventional heat pump while having about the same installation cost. The major conclusion of this study is - GCHP system performance improvement can be attained by improving the water-source heat pump package at less cost than by buying more ground coil. The following conclusions were drawn from the steady-state performance optimization results: (1) By adding about $100.00 to the manufacturer's cost off construction, both the heating and cooling COPs can be improved by 20% or more. (2) Cooling COP need not be sacrificed for the sake of heating performance and vice versa. 13 refs., 11 figs., 12 tabs.
Problem optimalnih kartografskih projekcija : Problem of the optimal cartographic projections
Krešimir Frankić
2014-12-01
Full Text Available Kartografske projekcije primjenjuju se za grafičko prikazivanje teritorija u sitnom mjerilu. Pravilnim izborom projekcije smanjuju se deformacije prikazanog teritorija, koji je omeđen graničnom linijom. U većini slučajeva ta granična linija nije neka matematički definirana krivulja, koja se najlakše prikazuje u obliku zatvorenog poligona. Optimalne kartografske projekcije, slijedeći neki definirani kriterij, trebale bi utvrditi konstante projekcije s najmanjim mogućim deformacijama. Airy-Kavrajski kriterij vodi direktno do optimizacije Euklidske norme, a to znači do metode najmanjih kvadrata. Brzi moderni kompjutori omogućuju jednostavnu optimizaciju bilo koje analitički definirane projekcije za teritorije čija granica se aproksimira konačnim nizom individualnih točaka. : Cartographic projections are basis for the graphical representation of various territories in small scale mapping. Proper selection of projection reduces the deformation of the presented territory, which is bounded by a boundary line. In most cases, this border line is not a mathematically defined curve, which is most easily displayed in the form of a closed polygon. The optimal cartographic projections based on a selected criterion of quality are those whose constants lead to the smallest value of the criterion. In the presented work it is recommended to use Airy-Kavrajski criterion whose minimization is actually minimization of the second Euclidean norm. The solution of optimal projections of various classes is reduced to the method of least squares. Fast modern computers enable the optimization of an arbitrary territory by evaluating the selected criterion in a finite number of points.
Stability of optimal-wave-front-sample coupling under sample translation and rotation
Anderson, Benjamin R; Eilers, Hergen
2015-01-01
The method of wavefront shaping to control optical properties of opaque media is a promising technique for authentication applications. One of the main challenges of this technique is the sensitivity of the wavefront-sample coupling to translation and/or rotation. To better understand how translation and rotation affect the wavefront- sample coupling we perform experiments in which we first optimize reflection from an opaque surface--to obtain an optimal wavefront--and then translate or rotate the surface and measure the new reflected intensity pattern. By using the correlation between the optimized and translated or rotated patterns we determine how sensitive the wavefront-sample coupling is. These experiments are performed for different spatial-light-modulator (SLM) bin sizes, beam-spot sizes, and nanoparticle concentrations. We find that all three parameters affect the different positional changes, implying that an optimization scheme can be used to maximize the stability of the wavefront-sample coupling. ...
Optimizing nonlinear beam coupling in low-symmetry crystals.
Shumelyuk, A; Volkov, A; Odoulov, S; Grabar, A; Stoyka, I; Evans, D R
2014-10-01
The purpose of this paper is to find the polarizations and spatial orientations of the two interacting counterpropagating coherent light waves which ensure the largest beam coupling in monoclinic photorefractive crystal. The results of calculations are presented that are verified experimentally with Sn₂P₂S₆.
Optimizing quality of care for couples with recurrent miscarriage
van den Boogaard, E.
2014-01-01
The first aim of our research was to make a step forwards to decipher the enigma of the definition of recurrent miscarriage. We showed that the risk of underlying antiphospholipid syndrome and carrier status of chromosomal abnormalities in couples with recurrent miscarriage is not related to obstetr
Optimal taxation of married couples with household production
Kreiner, Claus Thustrup; Kleven, Henrik Jacobsen
2007-01-01
The literature suggests that the concern for economic efficiency calls for individual-based taxation of married couples with a higher rate on the primary earner. This paper reconsiders the choice of tax unit in the Becker model of household production. In the absence of restrictions on the use of...
Topology optimization of Halbach magnet arrays using isoparametric projection
Lee, Jaewook; Nomura, Tsuyoshi; Dede, Ercan M.
2017-06-01
Topology optimization using isoparametric projection for the design of permanent magnet patterns in Halbach arrays is proposed. Based on isoparametric shape functions used in the finite element analysis, the permanent magnet strength and magnetization directions in a Halbach array are simultaneously optimized for a given design goal. To achieve fabrication feasibility of a designed Halbach magnet array, two design schemes are combined with the isoparametric projection method. First, a penalization scheme is proposed for designing the permanent magnets to have discrete magnetization direction angles. Second, an extrusion scheme is proposed for the shape regularization of the permanent magnet segments. As a result, the method systematically finds the optimal permanent magnet patterns of a Halbach array considering manufacturing feasibility. In two numerical examples, a circular shaped permanent magnet Halbach array is designed to minimize the magnitude of the magnetic flux density and to maximize the upward direction magnetic flux density inside the magnet array. Logical extension of the method to the design of permanent magnet arrays in linear actuators is provided, where the design goal is to maximize the actuator magnetic force.
Optimization of a catchment-scale coupled surface-subsurface hydrological model using pilot points
Danapour, Mehrdis; Stisen, Simon; Lajer Højberg, Anker
2016-04-01
Transient coupled surface-subsurface models are usually complex and contain a large amount of spatio-temporal information. In the traditional calibration approach, model parameters are adjusted against only few spatially aggregated observations of discharge or individual point observations of groundwater head. However, this approach doesn't enable an assessment of spatially explicit predictive model capabilities at the intermediate scale relevant for many applications. The overall objectives of this project is to develop a new model calibration and evaluation framework by combining distributed model parameterization and regularization with new types of objective functions focusing on optimizing spatial patterns rather than individual points or catchment scale features. Inclusion of detailed observed spatial patterns of hydraulic head gradients or relevant information obtained from remote sensing data in the calibration process could allow for a better representation of spatial variability of hydraulic properties. Pilot Points as an alternative to classical parameterization approaches, introduce great flexibility when calibrating heterogeneous systems without neglecting expert knowledge (Doherty, 2003). A highly parameterized optimization of complex distributed hydrological models at catchment scale is challenging due to the computational burden that comes with it. In this study the physically-based coupled surface-subsurface model MIKE SHE is calibrated for the 8,500 km2 area of central Jylland (Denmark) that is characterized by heterogeneous geology and considerable groundwater flow across topographical catchment boundaries. The calibration of the distributed conductivity fields is carried out with a pilot point-based approach, implemented using the PEST parameter estimation tool. To reduce the high number of calibration parameters, PEST's advanced singular value decomposition combined with regularization was utilized and a reduction of the model's complexity was
Parametric Design Optimization Of A Novel Permanent Magnet Coupling Using Finite Element Analysis
Högberg, Stig; Mijatovic, Nenad; Holbøll, Joachim;
2014-01-01
A parametric design optimization routine has been applied to a novel magnetic coupling with improved recyclability. Coupling designs are modeled in a 3-D finite element environ- ment, and evaluated by three design objectives: pull-out torque, torque density by magnet mass, and torque density...
Integrated optomechanical structural optimization through coupling of sensitivity matrixes
Riva, M.; Moschetti, M.
2016-07-01
The design of astronomical instrument is growing in dimension and complexity following ELT class telescopes. The availability of new structural material like composite ones is asking for more robust and reliable designing numerical tools. This paper wants to show a new opto-mechanical optimization approach developed starting from a previously developed integrated design framework. The Idea is to reduce number of iteration in a multi- variable structural optimization taking advantage of the embedded sensitivity routines that are available both in FEA software and in raytracing ones. This approach provide reduced iteration number mainly in case of high number of structural variable parameters.
Geospatial Optimization of Siting Large-Scale Solar Projects
Macknick, J.; Quinby, T.; Caulfield, E.; Gerritsen, M.; Diffendorfer, J.; Haines, S.
2014-03-01
Recent policy and economic conditions have encouraged a renewed interest in developing large-scale solar projects in the U.S. Southwest. However, siting large-scale solar projects is complex. In addition to the quality of the solar resource, solar developers must take into consideration many environmental, social, and economic factors when evaluating a potential site. This report describes a proof-of-concept, Web-based Geographical Information Systems (GIS) tool that evaluates multiple user-defined criteria in an optimization algorithm to inform discussions and decisions regarding the locations of utility-scale solar projects. Existing siting recommendations for large-scale solar projects from governmental and non-governmental organizations are not consistent with each other, are often not transparent in methods, and do not take into consideration the differing priorities of stakeholders. The siting assistance GIS tool we have developed improves upon the existing siting guidelines by being user-driven, transparent, interactive, capable of incorporating multiple criteria, and flexible. This work provides the foundation for a dynamic siting assistance tool that can greatly facilitate siting decisions among multiple stakeholders.
Hyland, D. C.; Bernstein, D. S.
1987-01-01
The underlying philosophy and motivation of the optimal projection/maximum entropy (OP/ME) stochastic modeling and reduced control design methodology for high order systems with parameter uncertainties are discussed. The OP/ME design equations for reduced-order dynamic compensation including the effect of parameter uncertainties are reviewed. The application of the methodology to several Large Space Structures (LSS) problems of representative complexity is illustrated.
王延敏; 姚平经
2003-01-01
In this paper, a new approach using artificial neural network and genetic algorithm for the optimization of the thermally coupled distillation is presented. Mathematical model can be constructed with artificial neural network based on the simulation results with ASPEN PLUS. Modified genetic algorithm was used to optimize the model. With the proposed model and optimization arithmetic, mathematical model can be calculated, decision variables and target value can be reached automatically and quickly. A practical example is used to demonstrate the algorithm.
Design and Optimization of UWB for Air Coupled GPR Applications
2014-10-01
evaluate the preliminary physical dimensions that can achieve minimum reflections at antenna’s feed point. These dimensions are then used in SolidWorks ...antenna structure to optimize both gain and impedance matching. The SolidWorks 3-D structural model is finally used for antenna fabrication. The...dimensions that can achieve minimum reflections at antenna’s feed point. These dimensions are then used in SolidWorks to create a 3D model that is imported
Coordination Implications of Software Coupling in Open Source Projects
Amrit, Chintan; Hillegersberg, van Jos; Ågerfalk, Pär
2010-01-01
The effect of software coupling on the quality of software has been studied quite widely since the seminal paper on software modularity by Parnas [1]. However, the effect of the increase in software coupling on the coordination of the developers has not been researched as much. In commercial softwar
Coordination Implications of Software Coupling in Open Source Projects
Amrit, Chintan Amrit; van Hillegersberg, Jos; Ågerfalk, Pär
2010-01-01
The effect of software coupling on the quality of software has been studied quite widely since the seminal paper on software modularity by Parnas [1]. However, the effect of the increase in software coupling on the coordination of the developers has not been researched as much. In commercial
Suman Acharyya; R E Amritkar
2015-02-01
The extension of the master stability function (MSF) to analyse stability of generalized synchronization for coupled nearly identical oscillators is discussed. The nearly identical nature of the coupled oscillators is due to some parameter mismatch while the dynamical equations are the same for all the oscillators. From the stability criteria of the MSF, we construct optimal networks with better synchronization property, i.e., the synchronization is stable for widest possible range of coupling parameters. In the optimized networks the nodes with parameter value at one extreme are selected as hubs. The pair of nodes with larger parameter difference are preferred to create links in the optimized networks, and the optimized networks are found to be disassortative in nature, i.e., the nodes with high degree tend to connect with nodes with low degree.
Shang, Linyuan; Zhao, Guozhong
2016-06-01
This article investigates topology optimization of a bi-material model for acoustic-structural coupled systems. The design variables are volume fractions of inclusion material in a bi-material model constructed by the microstructure-based design domain method (MDDM). The design objective is the minimization of sound pressure level (SPL) in an interior acoustic medium. Sensitivities of SPL with respect to topological design variables are derived concretely by the adjoint method. A relaxed form of optimality criteria (OC) is developed for solving the acoustic-structural coupled optimization problem to find the optimum bi-material distribution. Based on OC and the adjoint method, a topology optimization method to deal with large calculations in acoustic-structural coupled problems is proposed. Numerical examples are given to illustrate the applications of topology optimization for a bi-material plate under a low single-frequency excitation and an aerospace structure under a low frequency-band excitation, and to prove the efficiency of the adjoint method and the relaxed form of OC.
Optimal working conditions for thermoelectric generators with realistic thermal coupling
Apertet, Y; Glavatskaya, O; Goupil, C; Lecoeur, P
2011-01-01
We study how maximum output power can be obtained from a thermoelectric generator(TEG) with nonideal heat exchangers. We demonstrate with an analytic approach based on a force-flux formalism that the sole improvement of the intrinsic characteristics of thermoelectric modules including the enhancement of the figure of merit is of limited interest: the constraints imposed by the working conditions of the TEG must be considered on the same footing. Introducing an effective thermal conductance we derive the conditions which permit maximization of both efficiency and power production of the TEG dissipatively coupled to heat reservoirs. Thermal impedance matching must be accounted for as well as electrical impedance matching in order to maximize the output power. Our calculations also show that the thermal impedance does not only depend on the thermal conductivity at zero electrical current: it also depends on the TEG figure of merit. Our analysis thus yields both electrical and thermal conditions permitting optima...
Ultra High Brightness/Low Cost Fiber Coupled Packaging Project
National Aeronautics and Space Administration — The focus of the proposed effort is maximizing the brightness of fiber coupled laser diode pump sources at a minimum cost. The specific innovation proposed is to...
Robust, Low Loss Approach for Fiber to Waveguide Coupling Project
National Aeronautics and Space Administration — This NASA Phase I SBIR effort proposes to establish the feasibility of significantly improving coupling at fiber to waveguide interfaces for the manufacture of low...
Coupled Aeroheating and Ablative Thermal Response Simulation Tool Project
National Aeronautics and Space Administration — A predictive tool with tight coupling of the fluid and thermal physics will give insights into the conservatism of the uncoupled design process and could lead to...
Paramonov, Valentin
2013-01-01
The normal conducting Annular Coupled Structure (ACS) is applied for 190-400 MeV part of high intensity proton linac for the J-PARC. The ACS operating frequency is 972 MHz. The J-PARC ACS is strongly based on the results of previous investigations, especially results of Japan Hadron Project (JHP) research program in KEK. However, the design was revised and optimized to meet the requirements of reliability, operation efficiency and cost reduction. The cells shape of accelerating cells was optimized in total energy range to have high shunt impedance value together with the careful matching with the decreased coupling cells. The design of the bridge coupler cells was optimized to simplify mass production and shape of RF input cell together with matching window were optimized for higher operational reliability. Collected and adjusted all together, these modifications result in the significant effect. The ACS module design doesn't lose to another possible accelerating structures in RF parameters and dimensions. Pr...
Monolithic crystals for PET devices: Optical coupling optimization
González, A.J., E-mail: agonzalez@i3m.upv.es; Peiró, A.; Conde, P.; Hernández, L.; Moliner, L.; Orero, A.; Rodríguez-Álvarez, M.J.; Sánchez, F.; Soriano, A.; Vidal, L.F.; Benlloch, J.M.
2013-12-11
In this work we present a method to efficiently collect scintillation light when using monolithic scintillator crystals. The acceptance angle of the scintillation light has been reduced by means of optical devices reducing the border effect which typically affects continuous crystals. We have applied this procedure on gamma detectors for PET systems using both position sensitive PMTs and arrays of SiPMs. In the case of using SiPMs, this approach also helps to reduce the photosensor active area. We evaluated the method using PMTs with a variety of different crystals with thicknesses ranging from 10 to 24 mm. We found that our design allows the use of crystal blocks with a thickness of up to 18 mm without degrading the spatial resolution caused by edge effects and without a significant detriment to the energy resolution. These results were compared with simulated data. The first results of monolithic LYSO crystals coupled to an array of 256 SiPMs by means of individual optical light guides are also presented. -- Highlights: •Acceptance angle reduction decreases border effect in continuous crystals. •Experimental measurements with PMTs correlate well with simulated data. •Optical devices called faceplates serve to control the scintillation light angle. •Simulation on the light propagation for SiPMs requires exhaustive modeling.
A Novel Method for Assessing and Optimizing Software Project Process Based Risk Control
无
2006-01-01
A new approach for assessing and optimizing software project process based on software risk control pre-sented, which evaluates and optimizes software project process from the view of controlling the software project risks. A model for optimizing software risk control is given, a discrete optimization algorithm based on dynamic programming is proposed and an example of using above method to solve a problem is also included in this paper. By improving the old passive post-project control into an active effective pre-action, this new method can greatly promote the possibility of success of software projects.
Gao Ning; Sun Wei
2015-01-01
Based on the study of supply chain (SC) and SC optimization in engineering projects, a mixed integer nonlinear programming (MINLP) optimization model is developed to minimize the total SC cost for international petrochemical en-gineering projects. A steam cracking project is selected and analyzed, from which typical SC characteristics in international engineering projects in the area of petrochemical industry are summarized. The MINLP model is therefore developed and applied to projects with detailed data. The optimization results are analyzed and compared by the MINLP model, indicat-ing that they are appropriate to SC management practice in engineering projects, and are consistent with the optimal price-effective strategy in procurement. As a result, the model could provide useful guidance to SC optimization of international engineering projects in petrochemical industry, and improve SC management by selecting more reliable and qualiifed part-ner enterprises in SC for the project.
Optimizing strategy software for repetitive construction projects within multi-mode resources
Remon Fayek Aziz
2013-01-01
Estimating tender data for specific project is the most essential part in construction areas as of contractor’s view such as: proposed project duration with corresponding gross value and cash flows. This paper focuses on how to calculate tender data using Optimizing Strategy Software (OSS) for repetitive construction projects with identical activity’s duration in case of single number of crew such as: project duration, project/bid price, project maximum working capital, and project net presen...
Variational optimization with infinite projected entangled-pair states
Corboz, Philippe
2016-07-01
We present a scheme to perform an iterative variational optimization with infinite projected entangled-pair states, a tensor network ansatz for a two-dimensional wave function in the thermodynamic limit, to compute the ground state of a local Hamiltonian. The method is based on a systematic summation of Hamiltonian contributions using the corner-transfer-matrix method. Benchmark results for challenging problems are presented, including the two-dimensional Heisenberg model, the Shastry-Sutherland model, and the t -J model, which show that the variational scheme yields considerably more accurate results than the previously best imaginary-time evolution algorithm, with a similar computational cost and with a faster convergence towards the ground state.
Liu, Chao; Yang, Guigeng; Zhang, Yiqun
2015-01-01
The electrostatically controlled deployable membrane reflector (ECDMR) is a promising scheme to construct large size and high precision space deployable reflector antennas. This paper presents a novel design method for the large size and small F/D ECDMR considering the coupled structure-electrostatic problem. First, the fully coupled structural-electrostatic system is described by a three field formulation, in which the structure and passive electrical field is modeled by finite element method, and the deformation of the electrostatic domain is predicted by a finite element formulation of a fictitious elastic structure. A residual formulation of the structural-electrostatic field finite element model is established and solved by Newton-Raphson method. The coupled structural-electrostatic analysis procedure is summarized. Then, with the aid of this coupled analysis procedure, an integrated optimization method of membrane shape accuracy and stress uniformity is proposed, which is divided into inner and outer iterative loops. The initial state of relatively high shape accuracy and uniform stress distribution is achieved by applying the uniform prestress on the membrane design shape and optimizing the voltages, in which the optimal voltage is computed by a sensitivity analysis. The shape accuracy is further improved by the iterative prestress modification using the reposition balance method. Finally, the results of the uncoupled and coupled methods are compared and the proposed optimization method is applied to design an ECDMR. The results validate the effectiveness of this proposed methods.
Simulation of g factor for size optimization and coupling in phased array coil design
无
2006-01-01
The effect of geometric parameters of the coil element in an array on signal-to-noise ratio (SNR) and g factor of parallel imaging are analyzed, and the optimal parameters for the maximal SNR and minimal g factor are also given in this paper. In addition, the effects of coupling on SNR and g factor have been analyzed. The test results indicate that g factor for parallel imaging is greatly increased and SNR is decreased for coupling. According to the optimization, a six-channel parallel coil has been designed for torso imaging.
Optimization of Consumed Power in Two Different DC Motors Coupled Based on Genetic Algorithm
Mehrdad Jafarboland
2011-01-01
Full Text Available A single DC motor can be substituted by two different couple DC motors in submarines. By this way, by varying the speed of submarine, the power of propellant and subsequently the mechanical power of these motors would vary. One important promlem in controlling the mechanical coupling of these motors is the power sharing between them. In the previous reports the mechanical power was shared between them in nonoptimized manner. In this paper an optimized cantroller is indroduced that optimize the efficiency of the system. The power sharing between these motors would vary according to their speed. The proposed controller is based on Genetic Algoritm and is able to share the mechanical power between the motors in an optimized manner at different speeds. The simutation results shows the well behavior of system and also the optimize power sharing.
Shihao LIU
2015-06-01
Full Text Available Currently, most Chinese CNC machine tools' dynamic and static performances have large gap comparing with the similar foreign products, and the CNC machine tools users' human-centered design demand are ignored, which results in that the domestic CNC machine tools' overall competitiveness is relatively low. In order to solve the above problem, the ergonomics and coupling bionics are adopted to study collaborative optimization design method for CNC machine tools based on the domestic and foreign machine tool design method research achievement. The CNC machine tools' "man-machine-environment" interaction mechanism can be built by combining with ergonomic, and then the CNC ergonomic design criteria is obtained. Taking the coupling bionics as theoretical basis, the biological structures "morphology-structure-function-adaptive growth" multiple coupling mechanism can be studied, and the mechanical performance benefits structure can be extracted, then the CNC machine tools structural coupling bionic design technology is obtained by combining with the similarity principle. Combination of CNC machine tools' ergonomic design criteria and coupling bionic design technology, and considering the CNC machine tool performance's interaction and coupling mechanisms, a new multi-objective optimization design method can be obtained, which is verified through CNC machine tools' prototype experiments. The new optimization design method for CNC machine tools can not only help improve the whole machine's dynamic and static performance, but also has a bright prospect because of the "man-oriented" design concept.
Demosaicking Based on Optimization and Projection in Different Frequency Bands
Omer OsamaA
2008-01-01
Full Text Available Abstract A fast and effective iterative demosaicking algorithm is described for reconstructing a full-color image from single-color filter array data. The missing color values are interpolated on the basis of optimization and projection in different frequency bands. A filter bank is used to decompose an initially interpolated image into low-frequency and high-frequency bands. In the low-frequency band, a quadratic cost function is minimized in accordance with the observation that the low-frequency components of chrominance slowly vary within an object region. In the high-frequency bands, the high-frequency components of the unknown values are projected onto the high-frequency components of the known values. Comparison of the proposed algorithm with seven state-of-the-art demosaicking algorithms showed that it outperforms all of them for 20 images on average in terms of objective quality and that it is competitive with them from the subjective quality and complexity points of view.
Irwin Yousept
2010-07-01
Full Text Available An optimal control problem arising in the context of 3D electromagnetic induction heating is investigated. The state equation is given by a quasilinear stationary heat equation coupled with a semilinear time harmonic eddy current equation. The temperature-dependent electrical conductivity and the presence of pointwise inequality state-constraints represent the main challenge of the paper. In the first part of the paper, the existence and regularity of the state are addressed. The second part of the paper deals with the analysis of the corresponding linearized equation. Some suffcient conditions are presented which guarantee thesolvability of the linearized system. The final part of the paper is concerned with the optimal control. The aim of the optimization is to find the optimal voltage such that a desired temperature can be achieved optimally. The corresponding first-order necessary optimality condition is presented.
Xia Liu
2010-01-01
Full Text Available This paper reports investigations on the effect of antenna mutual coupling on performance of training-based Multiple-Input Multiple-Output (MIMO channel estimation. The influence of mutual coupling is assessed for two training-based channel estimation methods, Scaled Least Square (SLS and Minimum Mean Square Error (MMSE. It is shown that the accuracy of MIMO channel estimation is governed by the sum of eigenvalues of channel correlation matrix which in turn is influenced by the mutual coupling in transmitting and receiving array antennas. A water-filling-based procedure is proposed to optimize the training signal transmission to minimize the MIMO channel estimation errors.
Coupled heating/forming optimization of knitted reinforced composites
Pancrace, Johann
The feasibility of knitted fabric reinforcement for highly flexible composites has been investigated for the thermoforming process. The composite sheets were made through compression molding before being shaped. We used thermoplastic elastomers as matrices: Thermoplastic Elastomers and Thermoplastic Olefins. The knit reinforcement was provided by jersey knitted fabrics of polyester fibers. We first introduced the fundamentals involved in the study. The manufacturing is presented through compression molding and thermoforming. The latter is a two-step process: IR heating and plug/pressure assisted deformations. For the IR heating phase, several material properties have been characterized: the emissivity of matrices, absorption, reflection and transmission of radiations in the composite structure have been studied. We particularly paid attention to the reflection on the composite surfaces. The non-reflected or useful radiations leading to the heating are quantified and simulated for three emitter-composite configurations. It has been found that the emitter temperatures and the angle of incidence have significant roles in the IR heating phase. Thermal properties such as calorific capacity and thermal conductivity of the composites were also presented. Thermograms were carried out with an IR camera. Equipment and Thermogram acquisitions were both presented. Optimization of emitters was performed for a three emitter system. The objective function method has been illustrated. Regarding mechanical purposes, the characterizations of the matrices, reinforcements and flexible composites have been carried out. The studied loadings were uniaxial traction, pure shear and biaxial inflation. For the uniaxial extension, both the reinforcement and the composite were found highly anisotropic regarding the orientation of the loading toward the coursewise of the fabric. The resulting strains and stresses to rupture are also found anisotropic. However, for pure shear loading we observed
Sondos Mehri
2016-01-01
Full Text Available Electronic biomedical implantable sensors need power to perform. Among the main reported approaches, inductive link is the most commonly used method for remote powering of such devices. Power efficiency is the most important characteristic to be considered when designing inductive links to transfer energy to implantable biomedical sensors. The maximum power efficiency is obtained for maximum coupling and quality factors of the coils and is generally limited as the coupling between the inductors is usually very small. This paper is dealing with geometry optimization of inductively coupled printed spiral coils for powering a given implantable sensor system. For this aim, Iterative Procedure (IP and Genetic Algorithm (GA analytic based optimization approaches are proposed. Both of these approaches implement simple mathematical models that approximate the coil parameters and the link efficiency values. Using numerical simulations based on Finite Element Method (FEM and with experimental validation, the proposed analytic approaches are shown to have improved accurate performance results in comparison with the obtained performance of a reference design case. The analytical GA and IP optimization methods are also compared to a purely Finite Element Method based on numerical optimization approach (GA-FEM. Numerical and experimental validations confirmed the accuracy and the effectiveness of the analytical optimization approaches to design the optimal coil geometries for the best values of efficiency.
Concurrent, parallel, multiphysics coupling in the FACETS project
Cary, J. R.; Candy, J.; Cobb, J.; Cohen, R. H.; Epperly, T.; Estep, D. J.; Krasheninnikov, S.; Malony, A. D.; McCune, D. C.; McInnes, L.; Pankin, A.; Balay, S.; Carlsson, J. A.; Fahey, M. R.; Groebner, R. J.; Hakim, A. H.; Kruger, S. E.; Miah, M.; Pletzer, A.; Shasharina, S.; Vadlamani, S.; Wade-Stein, D.; Rognlien, T. D.; Morris, A.; Shende, S.; Hammett, G. W.; Indireshkumar, K.; Pigarov, A. Yu; Zhang, H.
2009-07-01
FACETS (Framework Application for Core-Edge Transport Simulations), is now in its third year. The FACETS team has developed a framework for concurrent coupling of parallel computational physics for use on Leadership Class Facilities (LCFs). In the course of the last year, FACETS has tackled many of the difficult problems of moving to parallel, integrated modeling by developing algorithms for coupled systems, extracting legacy applications as components, modifying them to run on LCFs, and improving the performance of all components. The development of FACETS abides by rigorous engineering standards, including cross platform build and test systems, with the latter covering regression, performance, and visualization. In addition, FACETS has demonstrated the ability to incorporate full turbulence computations for the highest fidelity transport computations. Early indications are that the framework, using such computations, scales to multiple tens of thousands of processors. These accomplishments were a result of an interdisciplinary collaboration among computational physics, computer scientists and applied mathematicians on the team.
Zhang, S. F.; Yin, J.; Liu, Y.; Sha, Z. H.; Ma, F. J.
2016-11-01
There always exists severe non-uniform wear of brake pad in large-megawatt wind turbine brake during the braking process, which has the brake pad worn out in advance and even threats the safety production of wind turbine. The root cause of this phenomenon is the non-uniform deformation caused by thermal-structural coupling effect between brake pad and disc while braking under the conditions of both high speed and heavy load. For this problem, mathematical model of thermal-structural coupling analysis is built. Based on the topology optimization method of Solid Isotropic Microstructures with Penalization, SIMP, structure topology optimization of brake pad is developed considering the deformation caused by thermal-structural coupling effect. The objective function is the minimum flexibility, and the structure topology optimization model of brake pad is established after indirect thermal- structural coupling analysis. Compared with the optimization result considering non-thermal- structural coupling, the conspicuous influence of thermal effect on brake pad wear and deformation is proven as well as the rationality of taking thermal-structural coupling effect as optimization condition. Reconstructed model is built according to the result, meanwhile analysis for verification is carried out with the same working condition. This study provides theoretical foundation for the design of high-speed and heavy-load brake pad. The new structure may provide design reference for improving the stress condition between brake pad and disc, enhancing the use ratio of friction material and increasing the working performance of large-megawatt wind turbine brake.
Pappas-DeLuca, Katina A.; Kraft, Joan Marie; Edwards, Sherri L.; Casillas, America; Harvey, S. Marie; Huszti, Heather C.
2006-01-01
Intervening with both members of a couple has been recommended as an important strategy for human immunodeficiency virus prevention. Analyses of focus groups and in-depth interviews with project personnel involved in recruitment and retention for the Partners Against Risk-Taking: A Networking and Evaluation Research Study project identified, at…
This report summarizes Phase II (site optimization) of the Nationwide Fund-lead Pump and Treat Optimization Project. This phase included conducting Remediation System Evaluations (RSEs) at each of the 20 sites selected in Phase I.
V. S. Bivde
2016-09-01
Full Text Available Coupling is an interdependence relationship between the modules of object-oriented software. It is a property with the most influence on quality attributes of the object-oriented software. Coupling with high values results in complex software design hence software professionals try to keep the coupling as low as possible. The values of coupling metrics are dependent on the type of input source code. Reusability is the main feature of object-oriented languages, so coupling occurs due to reuse of code modules. This paper investigates a correlation between the values of coupling metrics and the number of classes in the multimedia Java code. Here, a case study of a banking multimedia Java project with its forty different versions is conducted to comments on this correlation. The analysis of the results shows that, if the input source code is with a large number of classes then it results in high coupling values.
P. Ye. Uvarov
2009-09-01
Full Text Available In the article the basic problem of substantiation of parameters of optimization model of organizationaltechnological solutions for investment-building projects in the system of project management is considered.
QIAN Chang-ming; LUO Ai-hui; CHEN Guan-long
2007-01-01
Projection welding is a variation of electric resistance welding with the dynamic changes of the flow paths for heat and electrical properties with changing temperature caused by the large plastic deformation collapse of projection. As the joint type between the auto door hinge and the inner plate, projection welding may bring welding distortions and would affect the assembly quality of auto body. A comprehensive electric-thermal-mechanical numerical simulation was performed to quantitatively simulate the processes of projection welding by using a coupled finite element method. The mechanism of projection collapse and the formation process of nugget were discussed and good conclusions have been achieved comparing with the test results.
Wang, Shunquan; Zhou, Changhe; Ru, Huayi; Zhang, Yanyan
2005-07-20
Polymer deposition is a serious problem associated with the etching of fused silica by use of inductively coupled plasma (ICP) technology, and it usually prevents further etching. We report an optimized etching condition under which no polymer deposition will occur for etching fused silica with ICP technology. Under the optimized etching condition, surfaces of the fabricated fused silica gratings are smooth and clean. Etch rate of fused silica is relatively high, and it demonstrates a linear relation between etched depth and working time. Results of the diffraction of gratings fabricated under the optimized etching condition match theoretical results well.
Versatile and Extensible, Continuous-Thrust Trajectory Optimization Tool Project
National Aeronautics and Space Administration — We propose to develop an innovative, versatile and extensible, continuous-thrust trajectory optimization tool for planetary mission design and optimization of...
PDVSA Petrolera Sinovensa reservoir engineering project and optimization study
Campos, O. [PDVSA Petroleos de Venezuela SA, Caracas (Venezuela, Bolivarian Republic of). Petrolera Sinovensa; Patino, J. [Kizer Energy Inc., Katy, TX (United States); Chalifoux, G.V. [Petrospec Engineering Ltd., Edmonton, AB (Canada)
2009-07-01
This paper presented a development plan for an extra-heavy oil field in Venezuela's Orinoco belt involving cold heavy oil production (CHOP) as well as a thermal follow-up process to increase the ultimate recovery factor. A reservoir simulation model was used to model various reservoir formations in order to assess their oil recovery potential. Several thermal recovery processes were considered, such as steam assisted gravity drainage (SAGD), horizontal alternate steam drive (HASD), cyclic steam stimulation (CSS), horizontal continuous steam drive, and combined drive drainage (CDD). A geological static model and dynamic reservoir model were coupled for the well optimization evaluation. Production data were used to identify trends related to specific geological conditions. The study also examined methods of improving slotted liner designs and evaluated the use of electric heating as a means of improving CHOP performance. Results of the study showed that CDD offered the highest recovery rates as a follow-up to CHOP. The CDD process allowed for the use of existing wells drilled in the field. New horizontal wells will be placed between the existing wells. It was concluded that a CDD pilot should be implemented in order to prepare for a commercial implementation plan. 8 refs., 2 tabs., 14 figs.
Zhang, Songchuan; Xia, Youshen; Wang, Jun
2015-12-01
In this paper, we present a complex-valued projection neural network for solving constrained convex optimization problems of real functions with complex variables, as an extension of real-valued projection neural networks. Theoretically, by developing results on complex-valued optimization techniques, we prove that the complex-valued projection neural network is globally stable and convergent to the optimal solution. Obtained results are completely established in the complex domain and thus significantly generalize existing results of the real-valued projection neural networks. Numerical simulations are presented to confirm the obtained results and effectiveness of the proposed complex-valued projection neural network.
Optimizing strategy for repetitive construction projects within multi-mode resources
Remon Fayek Aziz
2013-03-01
Full Text Available Estimating tender data for specific project is the most essential part in construction areas as of a contractor’s view such as: proposed project duration with corresponding gross value and cash flows. Cash flow analysis of construction projects has a long history and has been an important topic in construction management. Determination of project cash flows is very sensitive, especially for repetitive construction projects. This paper focuses on how to calculate tender data for repetitive construction projects such as: project duration, project cost, project/bid price, project cash flows, project maximum working capital and project net present value that is equivalent to net profit at the beginning of the project. A simplified multi-objective optimization formulation will be presented that creates best tender data to contractor comparing with more feasible options that are generated from multi-mode resources in a given project. This mathematical formulation is intended to give more scenarios which provide a practical support for typical construction contractors who need to optimize resource utilization in order to minimize project duration, project/bid price and project maximum working capital while maximizing its net present value simultaneously. At the end of the paper, an illustrative example will be presented to demonstrate the applications of proposed technique to an optimization expressway of repetitive construction project.
Liu, Tongjun; Wang, Tongcai; Luan, Weiling; Cao, Qimin
2017-01-01
Waste heat recovery through thermoelectric generators is a promising way to improve energy conversion efficiency. This paper proposes a type of heat pipe assisted thermoelectric generator (HP-TEG) system. The expandable evaporator and condenser surface of the heat pipe facilitates the intensive assembly of thermoelectric (TE) modules to compose a compact device. Compared with a conventional layer structure thermoelectric generator, this system is feasible for the installment of more TE couples, thus increasing power output. To investigate the performance of the HP-TEG and the optimal number of TE couples, a theoretical model was presented and verified by experiment results. Further theoretical analysis results showed the performance of the HP-TEG could be further improved by optimizing the parameters, including the inlet air temperature, the thermal resistance of the heating section, and thermal resistance of the cooling structure. Moreover, applying a proper number of TE couples is important to acquire the best power output performance.
ZHONG DengHua; LI MingChao; HUANG Wei; LIU Yong
2009-01-01
To solve the engineering and scientific problems in construction diversion and its simulation analysis,a complete scheme is presented. Firstly, the complex constraint relationship was analyzed among main buildings, diversion buildings and flow control. Secondly, the time-space relationship model of construction diversion system and the general block diagram-oriented simulation model of diversion process were set up. Then, the corresponding numerical simulation method and 3D dynamic visual simulation method were put forward. Further, the simulation and optimization platform of construction diversion control process was developed, integrated with simulation modeling, computation and visualization. Finally, these methods were applied to a practical project successfully, showing that the modeling process is convenient, the computation and the visual analysis can be coupled effectively,and the results conform to practical state. They provide new theoretical principles and technical measures for analyzing the control problems encountered in construction diversion of hydraulic and hydroelectric engineering under complex conditions.
无
2009-01-01
To solve the engineering and scientific problems in construction diversion and its simulation analysis, a complete scheme is presented. Firstly, the complex constraint relationship was analyzed among main buildings, diversion buildings and flow control. Secondly, the time-space relationship model of construction diversion system and the general block diagram-oriented simulation model of diversion process were set up. Then, the corresponding numerical simulation method and 3D dynamic visual simulation method were put forward. Further, the simulation and optimization platform of construction diversion control process was developed, integrated with simulation modeling, computation and visualization. Finally, these methods were applied to a practical project successfully, showing that the modeling process is convenient, the computation and the visual analysis can be coupled effectively, and the results conform to practical state. They provide new theoretical principles and technical measures for analyzing the control problems encountered in construction diversion of hydraulic and hydroelectric engineering under complex conditions.
Optimal three-field block-preconditioners for models of coupled magma/mantle dynamics
Rhebergen, Sander; Wathen, Andrew J; Katz, Richard F
2014-01-01
For a prescribed porosity, the coupled magma/mantle flow equations can be formulated as a two field system of equations with velocity and pressure unknowns. Previous work has shown that while optimal preconditioners for the two field formulation can be constructed, the construction of preconditioners that are uniform with respect to model parameters is difficult. This limits the applicability of two field preconditioners in certain regimes of practical interest. We address this issue by reformulating the governing equations as a three field problem, which removes a term that was problematic in the two field formulation in favour of an additional equation for a pressure-like field. For the three-field problem, we develop and analyse new preconditioners and we show numerically that the new three-field preconditioners are optimal in terms of problem size and less sensitive to model parameters compared to the two-field preconditioner. This extends the applicability of optimal preconditioners for coupled mantle/ma...
LI Qiang; WU Jianxin; SUN Yan
2009-01-01
Dynamic optimization of electromechanical coupling system is a significant engineering problem in the field of mechatronics. The performance improvement of electromechanical equipment depends on the system design parameters. Aiming at the spindle unit of refitted machine tool for solid rocket, the vibration acceleration of tool is taken as objective function, and the electromechanical system design parameters are appointed as design variables. Dynamic optimization model is set up by adopting Lagrange-Maxwell equations, Park transform and electromechanical system energy equations. In the procedure of seeking high efficient optimization method, exponential function is adopted to be the weight function of particle swarm optimization algorithm. Exponential inertia weight particle swarm algorithm(EPSA), is formed and applied to solve the dynamic optimization problem of electromechanical system. The probability density function of EPSA is presented and used to perform convergence analysis. After calculation, the optimized design parameters of the spindle unit are obtained in limited time period. The vibration acceleration of the tool has been decreased greatly by the optimized design parameters. The research job in the paper reveals that the problem of dynamic optimization of electromechanical system can be solved by the method of combining system dynamic analysis with reformed swarm particle optimization. Such kind of method can be applied in the design of robots, NC machine, and other electromechanical equipments.
Wagner Sousa de Oliveira
2012-01-01
Full Text Available This paper makes a review and systematize methods and techniques of economic evaluation applied to renewable energy projects, specific to wind energy projects. Both project and cost methodologies of economic evaluation are reviewed for a model optimization construction for a proposed optimization model with its objective function most appropriated. It is necessary to engage in different approaches, but complementary, microeconomic project evaluation methods and optimization methods applied to engineering solutions in wind energy converter systems. Optimization model for economic evaluation of wind farms can be as an efficient planning and resource management, which is the key to the success of an energy project. Wind energy is one of the most potent alternative energy resources; however the economics of wind energy is not yet universally favorable to place wind at a competitive platform with coal and natural gas (fossil fuels. Economic evaluation models of wind projects developed would allow investors to better plan their projects, as well as provide valuable insight into the areas that require further development to improve the overall economics of wind energy projects.
Performance and Optimization for a Ground-Coupled Liquid Loop Heat Recovery Ventilation System
ZHOU Ya-su; Per FAHLEN; Torbj(o)rn LINDHOLM
2007-01-01
Ground-coupled heat pumps(GCHP) arecommonly used in residential heating system. To mitigatethe boreholes temperature dropping with operating time, anew exhaust-air recharging system is developed. The newrecharging system can be used in three operational modes.In this paper, a ground-coupled heat recovery ventilation(HRV) model is discussed. A thermal model is set up tofind the optimal brine flow rate and heat transfer allocationratio between exhaust and supply coils for maximum heatrecovery efficiency. Contrary to the conventional liquid-loopHRV systems, the brine temperature entering the exhaustcoil never goes blow zero(0℃), and hence defrosting isneedless in the ground-coupled HRV system. This can makethe ground-coupled HRV system over 20% more efficientthan a conventional HRV system at low outdoortemperatures.
Optimization of Vibration Reduction Ability of Ladder Tracks by FEM Coupled with ACO
Hao Jin
2015-01-01
Full Text Available Ladder track, which has drawn increased attention in scientific communities, is an effective method for reducing vibrations from underground railways. In order to optimize the vibration reduction ability of ladder track, a new method, that is, the finite element method (FEM coupled with ant colony optimization (ACO, has been proposed in this paper. We describe how to build the FEM model verified by the vibration tests in the Track Vibration Abatement and Control Laboratory and how to couple the FEM with ACO. The density and elasticity modulus of the sleeper pad are optimized using this method. After optimization, the vibration acceleration level of the supporting platform in the 1–200 Hz range was reduced from 102.8 dB to 94.4 dB. The optimized density of the sleeper pad is 620 kg/m3, and the optimized elasticity modulus of the sleeper pad is 6.25 × 106 N/m2.
Molina, Andrew; Smereka, Peter; Zimmerman, Paul M.
2016-03-01
The use of alternate coordinate systems as a means to improve the efficiency and accuracy of anharmonic vibrational structure analysis has seen renewed interest in recent years. While normal modes (which diagonalize the mass-weighted Hessian matrix) are a typical choice, the delocalized nature of this basis makes it less optimal when anharmonicity is in play. When a set of modes is not designed to treat anharmonicity, anharmonic effects will contribute to inter-mode coupling in an uncontrolled fashion. These effects can be mitigated by introducing locality, but this comes at its own cost of potentially large second-order coupling terms. Herein, a method is described which partially localizes vibrations to connect the fully delocalized and fully localized limits. This allows a balance between the treatment of harmonic and anharmonic coupling, which minimizes the error that arises from neglected coupling terms. Partially localized modes are investigated for a range of model systems including a tetramer of hydrogen fluoride, water dimer, ethene, diphenylethane, and stilbene. Generally, partial localization reaches ˜75% of maximal locality while introducing less than ˜30% of the harmonic coupling of the fully localized system. Furthermore, partial localization produces mode pairs that are spatially separated and thus weakly coupled to one another. It is likely that this property can be exploited in the creation of model Hamiltonians that omit the coupling parameters of the distant (and therefore uncoupled) pairs.
Wahlen-Strothman, Jacob M; Hermes, Matthew R; Degroote, Matthias; Qiu, Yiheng; Zhao, Jinmo; Dukelsky, Jorge; Scuseria, Gustavo E
2016-01-01
Coupled cluster and symmetry projected Hartree-Fock are two central paradigms in electronic structure theory. However, they are very different. Single reference coupled cluster is highly successful for treating weakly correlated systems, but fails under strong correlation unless one sacrifices good quantum numbers and works with broken-symmetry wave functions, which is unphysical for finite systems. Symmetry projection is effective for the treatment of strong correlation at the mean-field level through multireference non-orthogonal configuration interaction wavefunctions, but unlike coupled cluster, it is neither size extensive nor ideal for treating dynamic correlation. We here examine different scenarios for merging these two dissimilar theories. We carry out this exercise over the integrable Lipkin model Hamiltonian, which despite its simplicity, encompasses non-trivial physics for degenerate systems and can be solved via diagonalization for a very large number of particles. We show how symmetry projection...
刘兴高; 马龙华; 钱积新
2000-01-01
Internal thermally coupled distillation columns (ITCDIC) are the frontier of distillation energy saving research. In this paper, a novel energy saving model of ideal ITCDIC and a simulation algorithm are presented,upon which a series of comparative studies on energy savings with conventional distillation columns are carried out. Furthermore, we present an optimization model of ideal ITCDIC, which can be used to achieve the maximum energy saving and find the optimal design parameters directly. The binary system of benzene-toluene is adopted for the illustrative example of simulation and optimization. The results show that the maximum energy saving of ITCDIC is 52.25% (compared with energy consumption of conventional distillation under the minimum reflux ratio operation); the optimal design parameters are obtained, where the rectifying section pressure and the feed thermal condition are Pr=0.3006 MPa and q=0.5107 respectively.
OPTIMIZING OUTCOME IN THE UNIVERSITY-INDUSTRY TECHNOLOGY TRANSFER PROJECTS
Hamed ALAVI
2016-04-01
Full Text Available Transferring inventions of academic scientists to private enterprises for the purpose of commercialization is long known as University-Industry (firm Technology Transfer While the importance of this phenomenon is simultaneously raising in public and private sector, only a part of patented academic inventions succeed in passing the process of commercialization. Despite the fact that formal Technology Transfer process and licencing of patented innovations to third party is the main legal tool for safeguarding rights of academic inventors in commercialization of their inventions, it is not sufficient for transmitting tacit knowledge which is necessary in exploitation of transferred technology. Existence of reciprocal and complementary relations between formal and informal technology transfer process has resulted in formation of different models for university-industry organizational collaboration or even integration where licensee firms keep contact with academic inventors after gaining legal right for commercialization of their patented invention. Current paper argues that despite necessity for patents to legally pass the right of commercialization of an invention, they are not sufficient for complete knowledge transmission in the process of technology transfer. Lack of efficiency of formal mechanism to end the Technology Transfer loop makes an opportunity to create innovative interpersonal and organizational connections among patentee and licensee company. With emphasize on need for further elaboration of informal mechanisms as critical and underappreciated aspect of technology transfer process, article will try to answer the questions of how to optimize knowledge transmission process in the framework of University-Industry Technology Transfer Projects? What is the theoretical basis for university-industry technology transfer process? What are organization collaborative models which can enhance overall performance by improving transmission of
MENEJLJUK О. І.
2016-08-01
Full Text Available Raising of problem. The paper analyzes the numerical optimization methods of construction projects and reconstruction of engineering structures. Purpose. Possible ways of modeling organizational and technological solutions in construction are presented. Based on the analysis the most effective method of optimization by experimental and statistical modeling with application of modern computer programs in the field of project management and mathematical statistics is selected. Conclusion. An algorithm for solving optimization problems by means of experimental and statistical modeling is developed.
Optimizing strategy software for repetitive construction projects within multi-mode resources
Remon Fayek Aziz
2013-09-01
Full Text Available Estimating tender data for specific project is the most essential part in construction areas as of contractor’s view such as: proposed project duration with corresponding gross value and cash flows. This paper focuses on how to calculate tender data using Optimizing Strategy Software (OSS for repetitive construction projects with identical activity’s duration in case of single number of crew such as: project duration, project/bid price, project maximum working capital, and project net present value of the studied project. A simplified multi-objective optimization software (OSS will be presented that creates best tender data to contractor compared with more feasible options generated from multi-mode resources in a given project. OSS is intended to give more scenarios which provide practical support for typical construction contractors who need to optimize resource utilization in order to minimize project duration, project/bid price, and project maximum working capital while maximizing its net present value simultaneously. OSS is designed by java programing code system to provide a number of new and unique capabilities, including: (1 Ranking the obtained optimal plans according to a set of planner specified weights representing the relative importance of duration, price, maximum working capital and net present value in the analyzed project; (2 Visualizing and viewing the generated optimal trade-off; and (3 Providing seamless integration with available project management calculations. In order to provide the aforementioned capabilities of OSS, the system is implemented and developed in four main modules: (1 A user interface module; (2 A database module; (3 A running module; (4 A connecting module. At the end of the paper, an illustrative example will be presented to demonstrate and verify the applications of the proposed software (OSS to an optimization expressway of repetitive construction project.
Robust Optimization for Time-Cost Tradeoff Problem in Construction Projects
Ming Li; Guangdong Wu
2014-01-01
Construction projects are generally subject to uncertainty, which influences the realization of time-cost tradeoff in project management. This paper addresses a time-cost tradeoff problem under uncertainty, in which activities in projects can be executed in different construction modes corresponding to specified time and cost with interval uncertainty. Based on multiobjective robust optimization method, a robust optimization model for time-cost tradeoff problem is developed. In order to illus...
TIAN Ye-sheng;LI Hu-lin;JIANG Yong-yue;LONG Lei;JI Yong-zhe;ZHOU Jian-yue
2016-01-01
A coupling optimization design and experimental study method with uniform experimental and Aspen process simulation was established in this paper, which was used for stable isotope 13C separation of the double-stage cascade. Based on the above method, the optimization operating parameters were received. The coupling optimization simulation value showed good agreement with the experimental dates, and the average relative error was only 6.5%. On the other hand, compared with the initial test re...
Globus, M; Ratner, M
2002-01-01
Operation characteristics of a scintillation crystal, linked with the photomultiplier by a long transparent lightguide, are considered (such detection systems are used for monitoring the seawater pollution, scintillation measurements in magnetic field, etc.). This system is optimized with respect to the refractive index of the liquid, coupling the crystal with the lightguide, and the roughness degree of the crystal surface. It is shown that the energy resolution of the system can be significantly improved by using the coupling liquid with a refractive index somewhat less than that of the lightguide (a difference of about 0.2 is optimal). Light output and especially energy resolution becomes better with an increase of the roughness degree of the reflecting surface.
Analysis of Cell Load Coupling for LTE Network Planning and Optimization
Siomina, Iana
2012-01-01
System-centric modeling and analysis are of key significance in planning and optimizing cellular networks. In this paper, we provide a mathematical analysis of performance modeling for LTE networks. The system model characterizes the coupling relation between the cell load factors, taking into account non-uniform traffic demand and interference between the cells with arbitrary network topology. Solving the model enables a network-wide performance evaluation in resource consumption. We develop and prove both sufficient and necessary conditions for the feasibility of the load-coupling system, and provide results related to computational aspects for numerically approaching the solution. The theoretical findings are accompanied with experimental results to instructively illustrate the application in optimizing LTE network configuration.
Existence of the optimal measurable coupling and ergodicity for Markov processes
张绍义
1999-01-01
The existence theorem of the optimal measurable coupling of two probability kernels on a complete separable metric measurable space is proved. Then by this theorem, a general ergodicity theorem for Markov processes is obtained. And as an immediate application to particle systems the uniqueness theorem of the stationary distribution is supplemented, i.e. the uniqueness theorem also implies the existence of the stationary distribution.
On frequency optimization of assymetric resonant inductive coupling wireless power transfer links
2014-01-01
Resonant Inductive Coupling Wireless Power Transfer (RIC-WPT) is a leading field of research due to the growing number of applications that can benefit from this technology: from biomedical implants to consumer electronics, fractionated spacecraft and electric vehicles amongst others. However, current applications are limited to symetric point-to-point-links. New challenges and applications of RIC-WPT emphasize the necessity to explore, predict and optimize the behavior of these links for dif...
Thompson, Jonathan V.; Hokr, Brett H.; Yakovlev, Vladislav V.
2017-02-01
Light propagation in a turbid medium is typically considered for flat or regular surfaces. However, such an approximation often does not reflect an experimental reality, and, in this report, we attempt to optimize the surface of a scattering medium to improve the optical coupling into the medium. By making conical microchannels in a turbid medium using short-pulsed laser micro-drilling, we show that we were able to substantially increase the photon life-time and diffusion radius in the medium.
Simulator for Optimization of Software Project Cost and Schedule
P. K. Suri
2008-01-01
Full Text Available Each phase of the software design consumes some resources and hence has cost associated with it. In most of the cases cost will vary to some extent with the amount of time consumed by the design of each phase .The total cost of project, which is aggregate of the activities costs will also depends upon the project duration, can be cut down to some extent. The aim is always to strike a balance between the cost and time and to obtain an optimum software project schedule. An optimum minimum cost project schedule implies lowest possible cost and the associated time for the software project management. In this research an attempt has been made to solve the cost and schedule problem of software project using PERT network showing the details of the activities to be carried out for a software project development/management with the help of crashing, reducing software project duration at a minimum cost by locating a minimal cut in the duration of an activity of the original project design network. This minimal cut is then utilized to identify the project phases which should experience a duration modification in order to achieve the total software duration reduction. Crashing PERT networks can save a significant amount of money in crashing and overrun costs of a company. Even if there are no direct costs in the form of penalties for late completion of projects, there is likely to be intangible costs because of reputation damage.
Optimal control of two coupled spinning particles in the Euler-Lagrange picture
Delgado-Téllez, M.; Ibort, A.; Rodríguez de la Peña, T.; Salmoni, R.
2016-01-01
A family of optimal control problems for a single and two coupled spinning particles in the Euler-Lagrange formalism is discussed. A characteristic of such problems is that the equations controlling the system are implicit and a reduction procedure to deal with them must be carried out. The reduction of the implicit control equations arising in these problems will be discussed in the slightly more general setting of implicit equations defined by invariant one-forms on Lie groups. As an example the first order differential equations describing the extremal solutions of an optimal control problem for a single spinning particle, obtained by using Pontryagin’s Maximum Principle (PMP), will be found and shown to be completely integrable. Then, again using PMP, solutions for the problem of two coupled spinning particles will be characterized as solutions of a system of coupled non-linear matrix differential equations. The reduction of the implicit system will show that the reduced space for them is the product of the space of states for the independent systems, implying the absence of ‘entanglement’ in this instance. Finally, it will be shown that, in the case of identical systems, the degree three matrix polynomial differential equations determined by the optimal feedback law, constitute a completely integrable Hamiltonian system and some of its solutions are described explicitly.
Identifying Coupling Structure in Complex Systems through the Optimal Causation Entropy Principle
Sun, Jie; Bollt, Erik M
2014-01-01
Inferring the coupling structure of complex systems from time series data in general by means of statistical and information-theoretic techniques is a challenging problem in applied science. The reliability of statistical inferences requires the construction of suitable information-theoretic measures that take into account both direct and indirect influences, manifest in the form of information flows, between the components within the system. In this work, we present an application of the optimal causation entropy (oCSE) principle to identify the coupling structure of a synthetic biological system, the repressilator. Specifically, when the system reaches an equilibrium state, we use a stochastic perturbation approach to extract time series data that approximate a linear stochastic process. Then, we present and jointly apply the aggregative discovery and progressive removal algorithms based on the oCSE principle to infer the coupling structure of the system from the measured data. Finally, we show that the suc...
Desensitized Optimal Filtering and Sensor Fusion Tool Kit Project
National Aeronautics and Space Administration — Research on desensitized optimal filtering techniques and a navigation and sensor fusion tool kit using advanced filtering techniques is proposed. Research focuses...
Accelerating ATM Optimization Algorithms Using High Performance Computing Hardware Project
National Aeronautics and Space Administration — NASA is developing algorithms and methodologies for efficient air-traffic management (ATM). Several researchers have adopted an optimization framework for solving...
Collaborative Object Framework for Adaptive System Optimization Project
National Aeronautics and Space Administration — The proposed innovation is to combine traditional and cutting edge optimization techniques into an existing powerful object based organic enterprise decision network...
Accelerating ATM Optimization Algorithms Using High Performance Computing Hardware Project
National Aeronautics and Space Administration — NASA is developing algorithms and methodologies for efficient air-traffic management. Several researchers have adopted an optimization framework for solving problems...
Power Grid Construction Project Portfolio Optimization Based on Bi-level programming model
Zhao, Erdong; Li, Shangqi
2017-08-01
As the main body of power grid operation, county-level power supply enterprises undertake an important emission to guarantee the security of power grid operation and safeguard social power using order. The optimization of grid construction projects has been a key issue of power supply capacity and service level of grid enterprises. According to the actual situation of power grid construction project optimization of county-level power enterprises, on the basis of qualitative analysis of the projects, this paper builds a Bi-level programming model based on quantitative analysis. The upper layer of the model is the target restriction of the optimal portfolio; the lower layer of the model is enterprises’ financial restrictions on the size of the enterprise project portfolio. Finally, using a real example to illustrate operation proceeding and the optimization result of the model. Through qualitative analysis and quantitative analysis, the bi-level programming model improves the accuracy and normative standardization of power grid enterprises projects.
Zhang Biao; Qi Hong; Sun Shuang-Cheng; Ruan Li-Ming; Tan He-Ping
2016-01-01
In this study, a continuous ant colony optimization algorithm on the basis of probability density function was applied to the inverse problems of one-dimensional coupled radiative and conductive heat transfer...
Inverse optimal sliding mode control of spacecraft with coupled translation and attitude dynamics
Pukdeboon, Chutiphon
2015-10-01
This paper proposes two robust inverse optimal control schemes for spacecraft with coupled translation and attitude dynamics in the presence of external disturbances. For the first controller, an inverse optimal control law is designed based on Sontag-type formula and the control Lyapunov function. Then a robust inverse optimal position and attitude controller is designed by using a new second-order integral sliding mode control method to combine a sliding mode control with the derived inverse optimal control. The global asymptotic stability of the proposed control law is proved by using the second method of Lyapunov. For the other control law, a nonlinear H∞ inverse optimal controller for spacecraft position and attitude tracking motion is developed to achieve the design conditions of controller gains that the control law becomes suboptimal H∞ state feedback control. The ultimate boundedness of system state is proved by using the Lyapunov stability theory. Both developed robust inverse optimal controllers can minimise a performance index and ensure the stability of the closed-loop system and external disturbance attenuation. An example of position and attitude tracking manoeuvres is presented and simulation results are included to show the performance of the proposed controllers.
Optimization of Serial Combined System of Ground-Coupled Heat Pump and Solar Collector
ZHAO Jun; CHEN Yan; LU Suzhen; CUI Junkui
2009-01-01
A mathematical optimization model was set up for a ground-solar combined system based on in-situ experimental results,in which the solar collector was combined serially with a ground-coupled heat pump(GCHP).The universal optimal equations were solved by the constrained variable metric method considering both the performance and economics.Then the model was applied to a specific case concerning an actual solar assisted GCHP system for space heating.The results indicated a system coefficient of performance(COP)of 3.9 for the optimal method under the seriaI heating mode,and 3.2 for the conventional one.In addition,the optimum solution also showed advantages in energy and cost saving.1eading to a 16.7%improvement in the heat pump performance at 17.2%less energy consumption and 11.8%lower annual cost,respectively.
Cai, Qiong; Adjiman, Claire S.; Brandon, Nigel P.
2014-12-01
The penetration of intermittent renewable energies requires the development of energy storage technologies. High temperature electrolysis using solid oxide electrolyser cells (SOECs) as a potential energy storage technology, provides the prospect of a cost-effective and energy efficient route to clean hydrogen production. The development of optimal control strategies when SOEC systems are coupled with intermittent renewable energies is discussed. Hydrogen production is examined in relation to energy consumption. Control strategies considered include maximizing hydrogen production, minimizing SOEC energy consumption and minimizing compressor energy consumption. Optimal control trajectories of the operating variables over a given period of time show feasible control for the chosen situations. Temperature control of the SOEC stack is ensured via constraints on the overall temperature difference across the cell and the local temperature gradient within the SOEC stack, to link materials properties with system performance; these constraints are successfully managed. The relative merits of the optimal control strategies are analyzed.
OPTIMAL DESIGN OF DEEP FOUNDATION PIT CONSTRUCTION PROJECT IN WUHAN
Nguyen Xuan Loi, Wu Li*, Nguyen Khanh Tung
2016-01-01
Deep foundation pit construction project is one of hot and difficult problems in rock soil engineering. How to control the deformation of the pits effectively and economically is what we all want. Retaining structure deformation of foundation pit is an important factor on the deformation of foundation pit. Reference of domestic and foreign research and the experience of similar projects, combined with the characteristics of Wuhan project, calculation, analyses and compared two design options ...
A generalized public goods game with coupling of individual ability and project benefit
Zhong, Li-Xin; Xu, Wen-Juan; He, Yun-Xin; Zhong, Chen-Yang; Chen, Rong-Da; Qiu, Tian; Shi, Yong-Dong; Ren, Fei
2017-08-01
Facing a heavy task, any single person can only make a limited contribution and team cooperation is needed. As one enjoys the benefit of the public goods, the potential benefits of the project are not always maximized and may be partly wasted. By incorporating individual ability and project benefit into the original public goods game, we study the coupling effect of the four parameters, the upper limit of individual contribution, the upper limit of individual benefit, the needed project cost and the upper limit of project benefit on the evolution of cooperation. Coevolving with the individual-level group size preferences, an increase in the upper limit of individual benefit promotes cooperation while an increase in the upper limit of individual contribution inhibits cooperation. The coupling of the upper limit of individual contribution and the needed project cost determines the critical point of the upper limit of project benefit, where the equilibrium frequency of cooperators reaches its highest level. Above the critical point, an increase in the upper limit of project benefit inhibits cooperation. The evolution of cooperation is closely related to the preferred group-size distribution. A functional relation between the frequency of cooperators and the dominant group size is found.
Szatmári, Daniel
2015-12-01
Disadvantages of the currently used Křovák's map projection in the Slovak Republic, such as large scale distortion, became evident after the division of Czechoslovakia. The aim of this paper is to show the results of the optimization of cartographic projections using Chebyshev's theorem for conformal projections and its application to the territory of the Slovak Republic. The calculus used, the scale distortions achieved and their comparison with the scale distortions of currently used map projections will be demonstrated.
Aero-Acoustic-Structural Optimization Analysis and Testing Project
National Aeronautics and Space Administration — This proposal effort is concerned with the development of a novel multidisciplinary optimization scheme and computer software for the effective design of advanced...
Desensitized Optimal Filtering and Sensor Fusion Tool Kit Project
National Aeronautics and Space Administration — It is proposed to develop desensitized optimal filtering techniques and to implement these algorithms in a navigation and sensor fusion tool kit. These proposed...
METROSIM: Metroplex-Wide Flight Planning and Optimization Project
National Aeronautics and Space Administration — The key innovation of this effort is the development of a Metroplex-based arrival, departure, and surface optimization system which we call MetroSim. Linking with...
METROSIM: Metroplex-Wide Flight Planning and Optimization Project
National Aeronautics and Space Administration — MetroSim is a Metroplex-based arrival, departure, and surface optimization. Linking with both the NASA-developed Traffic Management Advisor (TMA) tool as well as the...
Multidisciplinary Aerospace Systems Optimization: Computational AeroSciences (CAS) Project
Kodiyalam, S.; Sobieski, Jaroslaw S. (Technical Monitor)
2001-01-01
The report describes a method for performing optimization of a system whose analysis is so expensive that it is impractical to let the optimization code invoke it directly because excessive computational cost and elapsed time might result. In such situation it is imperative to have user control the number of times the analysis is invoked. The reported method achieves that by two techniques in the Design of Experiment category: a uniform dispersal of the trial design points over a n-dimensional hypersphere and a response surface fitting, and the technique of krigging. Analyses of all the trial designs whose number may be set by the user are performed before activation of the optimization code and the results are stored as a data base. That code is then executed and referred to the above data base. Two applications, one of the airborne laser system, and one of an aircraft optimization illustrate the method application.
Finite Element Multidisciplinary Optimization Simulation of Flight Vehicles Project
National Aeronautics and Space Administration — The proposed effort is concerned with the development of a novel optimization scheme and computer software for the effective design of advanced aerospace vehicles....
Collaborative Object Framework for Adaptive System Optimization Project
National Aeronautics and Space Administration — TeamVision proposes that we research the feasibility of incorporating an adaptive object based optimization system into an existing multi-user object oriented...
Thermal-economic modeling and optimization of vertical ground-coupled heat pump
Sanaye, Sepehr; Niroomand, Behzad [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16488 (Iran)
2009-04-15
The optimal design process of a ground source heat pump includes thermal modeling of the system and selection of optimal design parameters which affect the system performance as well as initial and operational costs. In this paper, the modeling and optimizing processes of a ground-coupled heat pump (GCHP) with closed vertical ground heat exchanger (VGHX) are presented. To verify the modeling procedure of heat pump and VGHX systems, the simulation outputs were compared with the corresponding values reported in the literature and acceptable accuracy was obtained. Then an objective function (the sum of annual operating and investment costs of the system) was defined and minimized, exposed to the specified constraints to estimate the optimum design parameters (decision variables). Two Nelder-Mead and genetic algorithm optimization techniques were applied to guarantee the validity of the optimization results. For the given heating/cooling loads and various climatic conditions, the optimum values of heat pump design parameters (saturated temperature/pressure of condenser and evaporator) as well as VGHX design parameters (inlet and outlet temperatures of the ground water source, pipe diameter, depth and number of boreholes) were predicted. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, soil type, and number of boreholes were discussed. Finally, the sensitivity analysis of change in optimum design parameters with increase in the investment and electricity costs was performed. (author)
Rock, Emily E.; Steiner, Jennifer L.; Rand, Kevin L.; Bigatti, Silvia M.
2014-01-01
PURPOSE An estimated 10–40% of breast cancer (BC) patients report negative changes to their partnered relationships. Literature suggests that for these patients, marital satisfaction is related to depression and other quality of life factors which are associated with survivorship and treatment response. However, existing literature does not provide a clear explanation of the factors that strengthen vs. create strain in couples facing cancer. Given the benefits of a satisfying relationship to patient quality of life, it is important to better understand factors that put patients at greater risk for marital difficulties. This study examined the differential and combined roles of hope and optimism among BC patients and their partners on patient marital satisfaction. METHOD Fifty-six breast cancer patient-partner dyads completed study questionnaires as part of a larger study. Regression analyses were used to examine the main and interaction effects of patient and partner hope and optimism on patient marital satisfaction. RESULTS AND CONCLUSION Higher patient and partner hope predicted greater patient marital satisfaction, whereas optimism did not. These results are divergent from the literature on optimism and well-being, which shows the importance of studying these two traits concurrently. Interaction effects suggest certain combinations of patient and partner hope and optimism are more beneficial than others for patient marital satisfaction and suggest a dyadic approach is important for investigation of well-being in breast cancer. PMID:24687536
Toreti, A.; Naveau, P.; Zampieri, M.; Schindler, A.; Scoccimarro, E.; Xoplaki, E.; Dijkstra, H.A.|info:eu-repo/dai/nl/073504467; Gualdi, S.; Luterbacher, J.
2013-01-01
Precipitation extremes are expected to increase in a warming climate; thus, it is essential to characterize their potential future changes. Here we evaluate eight high-resolution global climate model simulations in the twentieth century and provide new evidence on projected global precipitation
Toreti, A.; Naveau, P.; Zampieri, M.; Schindler, A.; Scoccimarro, E.; Xoplaki, E.; Dijkstra, H.A.; Gualdi, S.; Luterbacher, J.
2013-01-01
Precipitation extremes are expected to increase in a warming climate; thus, it is essential to characterize their potential future changes. Here we evaluate eight high-resolution global climate model simulations in the twentieth century and provide new evidence on projected global precipitation extr
Drag &Drop, Multiphysics & Neural Net-based Lab-on-Chip Optimization Software Project
National Aeronautics and Space Administration — The overall objective of this project is to develop a drag and drop, component library (fluidic lego) based, system simulation and optimization software for entire...
Optimization of coupled multiphysics methodology for safety analysis of pebble bed modular reactor
Mkhabela, Peter Tshepo
The research conducted within the framework of this PhD thesis is devoted to the high-fidelity multi-physics (based on neutronics/thermal-hydraulics coupling) analysis of Pebble Bed Modular Reactor (PBMR), which is a High Temperature Reactor (HTR). The Next Generation Nuclear Plant (NGNP) will be a HTR design. The core design and safety analysis methods are considerably less developed and mature for HTR analysis than those currently used for Light Water Reactors (LWRs). Compared to LWRs, the HTR transient analysis is more demanding since it requires proper treatment of both slower and much longer transients (of time scale in hours and days) and fast and short transients (of time scale in minutes and seconds). There is limited operation and experimental data available for HTRs for validation of coupled multi-physics methodologies. This PhD work developed and verified reliable high fidelity coupled multi-physics models subsequently implemented in robust, efficient, and accurate computational tools to analyse the neutronics and thermal-hydraulic behaviour for design optimization and safety evaluation of PBMR concept The study provided a contribution to a greater accuracy of neutronics calculations by including the feedback from thermal hydraulics driven temperature calculation and various multi-physics effects that can influence it. Consideration of the feedback due to the influence of leakage was taken into account by development and implementation of improved buckling feedback models. Modifications were made in the calculation procedure to ensure that the xenon depletion models were accurate for proper interpolation from cross section tables. To achieve this, the NEM/THERMIX coupled code system was developed to create the system that is efficient and stable over the duration of transient calculations that last over several tens of hours. Another achievement of the PhD thesis was development and demonstration of full-physics, three-dimensional safety analysis
U-D factorisation of the strengthened discrete-time optimal projection equations
Van Willigenburg, L. Gerard; De Koning, Willem L.
2016-04-01
Algorithms for optimal reduced-order dynamic output feedback control of linear discrete-time systems with white stochastic parameters are U-D factored in this paper. U-D factorisation enhances computational accuracy, stability and possibly efficiency. Since U-D factorisation of algorithms for optimal full-order output feedback controller design was recently published by us, this paper focusses on the U-D factorisation of the optimal oblique projection matrix that becomes part of the solution as a result of order-reduction. The equations producing the solution are known as the optimal projection equations which for discrete-time systems have been strengthened in the past. The U-D factored strengthened discrete-time optimal projection equations are presented in this paper by means of a transformation that has to be applied recursively until convergence. The U-D factored and conventional algorithms are compared through a series of examples.
Andersson, Johan [JA Streamflow AB, Aelvsjoe (Sweden)
2005-02-15
A part (Task 4) of the International DECOVALEX III project on coupled thermo-hydro-mechanical (T-H-M) processes focuses on T-H-M modelling applications in safety and performance assessment of deep geological nuclear waste repositories. A previous phase, DECOVALEX II, saw a need to improve such modelling. In order to address this need Task 4 of DECOVALEX III has: Analysed two major T-H-M experiments (Task 1 and Task 2) and three different Bench Mark Tests (Task 3) set-up to explore the significance of T-H-M in some potentially important safety assessment applications. Compiled and evaluated the use of T-H-M modelling in safety assessments at the time of the year 2000. Organised a forum a forum of interchange between PA-analysts and THM modelers at each DECOVALEX III workshop. Based on this information the current report discusses the findings and strives for reaching recommendations as regards good practices in addressing coupled T-H-M issues in safety assessments. The full development of T-H-M modelling is still at an early stage and it is not evident whether current codes provide the information that is required. However, although the geosphere is a system of fully coupled processes, this does not directly imply that all existing coupled mechanisms must be represented numerically. Modelling is conducted for specific purposes and the required confidence level should be considered. It is necessary to match the confidence level with the modelling objective. Coupled THM modelling has to incorporate uncertainties. These uncertainties mainly concern uncertainties in the conceptual model and uncertainty in data. Assessing data uncertainty is important when judging the need to model coupled processes. Often data uncertainty is more significant than the coupled effects. The emphasis on the need for THM modelling differs among disciplines. For geological radioactive waste disposal in crystalline and other similar hard rock formations DECOVALEX III shows it is essential to
Optimization of Time Restriction in Construction Project Management Using Lingo and M.S.Excel
Komal Kiran
2015-09-01
Full Text Available This study is an attempt to identify the minimum time of a construction project using the critical path method and linear programming model. A systematic analysis is attempted by developing a work breakdown structure for entire project to establish work elements for quantifying various resources against time and cost. A network is established taking into consideration all the predecessor and successor activities. The network is then optimized through crashing of activities so as to obtain optimal solution and serves as a base for optimizing total project cost. Finally, linear programming model is used to formulate the system of crashing network for minimum time by LINGO model and Microsoft Excel. These models consider many considerations of project thus reducing the duration of project. Ultimately, comparison of both the software outputs and the manual calculations is done and the best verifier is determined.
Sippel, Sebastian; Zscheischler, Jakob; Mahecha, Miguel D.; Orth, Rene; Reichstein, Markus; Vogel, Martha; Seneviratne, Sonia I.
2017-05-01
The Earth's land surface and the atmosphere are strongly interlinked through the exchange of energy and matter. This coupled behaviour causes various land-atmosphere feedbacks, and an insufficient understanding of these feedbacks contributes to uncertain global climate model projections. For example, a crucial role of the land surface in exacerbating summer heat waves in midlatitude regions has been identified empirically for high-impact heat waves, but individual climate models differ widely in their respective representation of land-atmosphere coupling. Here, we compile an ensemble of 54 combinations of observations-based temperature (T) and evapotranspiration (ET) benchmarking datasets and investigate coincidences of T anomalies with ET anomalies as a proxy for land-atmosphere interactions during periods of anomalously warm temperatures. First, we demonstrate that a large fraction of state-of-the-art climate models from the Coupled Model Intercomparison Project (CMIP5) archive produces systematically too frequent coincidences of high T anomalies with negative ET anomalies in midlatitude regions during the warm season and in several tropical regions year-round. These coincidences (high T, low ET) are closely related to the representation of temperature variability and extremes across the multi-model ensemble. Second, we derive a land-coupling constraint based on the spread of the T-ET datasets and consequently retain only a subset of CMIP5 models that produce a land-coupling behaviour that is compatible with these benchmark estimates. The constrained multi-model simulations exhibit more realistic temperature extremes of reduced magnitude in present climate in regions where models show substantial spread in T-ET coupling, i.e. biases in the model ensemble are consistently reduced. Also the multi-model simulations for the coming decades display decreased absolute temperature extremes in the constrained ensemble. On the other hand, the differences between projected
S. Sippel
2017-05-01
Full Text Available The Earth's land surface and the atmosphere are strongly interlinked through the exchange of energy and matter. This coupled behaviour causes various land–atmosphere feedbacks, and an insufficient understanding of these feedbacks contributes to uncertain global climate model projections. For example, a crucial role of the land surface in exacerbating summer heat waves in midlatitude regions has been identified empirically for high-impact heat waves, but individual climate models differ widely in their respective representation of land–atmosphere coupling. Here, we compile an ensemble of 54 combinations of observations-based temperature (T and evapotranspiration (ET benchmarking datasets and investigate coincidences of T anomalies with ET anomalies as a proxy for land–atmosphere interactions during periods of anomalously warm temperatures. First, we demonstrate that a large fraction of state-of-the-art climate models from the Coupled Model Intercomparison Project (CMIP5 archive produces systematically too frequent coincidences of high T anomalies with negative ET anomalies in midlatitude regions during the warm season and in several tropical regions year-round. These coincidences (high T, low ET are closely related to the representation of temperature variability and extremes across the multi-model ensemble. Second, we derive a land-coupling constraint based on the spread of the T–ET datasets and consequently retain only a subset of CMIP5 models that produce a land-coupling behaviour that is compatible with these benchmark estimates. The constrained multi-model simulations exhibit more realistic temperature extremes of reduced magnitude in present climate in regions where models show substantial spread in T–ET coupling, i.e. biases in the model ensemble are consistently reduced. Also the multi-model simulations for the coming decades display decreased absolute temperature extremes in the constrained ensemble. On the other hand
OPUS: Optimal Projection for Uncertain Systems. Volume 1
1991-09-01
coupled Riccati equations, and shown *Asslstsa Profesor , Department of Mechanial and Asoepece Eng n eing, Flodda Institute of Technolog, Melbourne...discrete-time and sampled- data Related Problems - Solution via Decision Methods," L=E TAO. AC-20, contol lws icludng bth ingl andmultrate568. 1075.coto as
Vittorio M. N. Passaro
2012-02-01
Full Text Available Slot waveguides are becoming more and more attractive optical components, especially for chemical and bio-chemical sensing. In this paper an accurate analysis of slot waveguide fabrication tolerances is carried out, in order to find optimum design criteria for either homogeneous or absorption sensing mechanisms, in cases of low and high aspect ratio slot waveguides. In particular, we have focused on Silicon On Insulator (SOI technology, representing the most popular technology for this kind of devices, simultaneously achieving high integration capabilities, small dimensions and low cost. An accurate analysis of single mode behavior for high aspect ratio slot waveguide has been also performed, in order to provide geometric limits for waveguide design purposes. Finally, the problem of coupling into a slot waveguide is addressed and a very compact and efficient slot coupler is proposed, whose geometry has been optimized to give a strip-slot-strip coupling efficiency close to 100%.
A Multi-Model Reduction Technique for Optimization of Coupled Structural-Acoustic Problems
Creixell Mediante, Ester; Jensen, Jakob Søndergaard; Brunskog, Jonas;
2016-01-01
Finite Element models of structural-acoustic coupled systems can become very large for complex structures with multiple connected parts. Optimization of the performance of the structure based on harmonic analysis of the system requires solving the coupled problem iteratively and for several...... frequencies, which can become highly time consuming. Several modal-based model reduction techniques for structure-acoustic interaction problems have been developed in the literature. The unsymmetric nature of the pressure-displacement formulation of the problem poses the question of how the reduction modal...... base should be formed, given that the modal vectors are not orthogonal due to the asymmetry of the system matrices. In this paper, a multi-model reduction (MMR) technique for structure-acoustic interaction problems is developed. In MMR, the reduction base is formed with the modal vectors of a family...
Current status of the international DECOVALEX project: thermal-hydraulic-mechanical couplings
Kang, C. H.; Hwang, Y. S.; Kim, J
1998-01-01
THM coupling is an important issue to assess the safety of the HLW repositories. In this art report the current status of the international DECOVALEX project was reviewed to understand the most updated R and D direction on the groundwater flow assessment coupled with the decay heat and mechanical stress around a repository. Important progresses of DECOVALEX I, II, III and 2 were studied. Results show that even though there are good agreements on the predictions of stress and temperature, still the prediction of flow in discrete fracture network is incomplete. (author). 21 refs., 28 tabs., 33 figs
Generalized Projective Synchronization between Two Complex Networks with Time-Varying Coupling Delay
SUN Mei; ZENG Chang-Yan; TIAN Li-Xin
2009-01-01
Generalized projective synchronization (GPS) between two complex networks with time-varying coupling delay is investigated. Based on the Lyapunov stability theory, a nonlinear controller and adaptive updated laws are designed. Feasibility of the proposed scheme is proven in theory. Moreover, two numerical examples are presented, using the energy resource system and Lü's system [Physica A 382 (2007) 672] as the nodes of the networks. GPS between two energy resource complex networks with time-varying coupling delay is achieved. This study can widen the application range of the generalized synchronization methods and will be instructive for the demand-supply of energy resource in some regions of China.
Bourke, Levi; Blaikie, Richard J.
2017-09-01
Grating coupled near-field interference lithography has the ability to produce deep-subwavelength interference patterns. Simulations of these systems is very computationally intensive. An inverse design procedure employing a genetic algorithm is utilized here to massively reduce the computational load and allow for the design of systems capable of interfering extremely high numerical apertures. This method is used to optimize systems with an interference patterns with a half pitch of λ /40 corresponding to a numerical aperture of 20. It is also used to demonstrate interference of higher | m| diffraction orders.
Nguyen, Howard; Willacy, Karen; Allen, Mark
2012-01-01
KINETICS is a coupled dynamics and chemistry atmosphere model that is data intensive and computationally demanding. The potential performance gain from using a supercomputer motivates the adaptation from a serial version to a parallelized one. Although the initial parallelization had been done, bottlenecks caused by an abundance of communication calls between processors led to an unfavorable drop in performance. Before starting on the parallel optimization process, a partial overhaul was required because a large emphasis was placed on streamlining the code for user convenience and revising the program to accommodate the new supercomputers at Caltech and JPL. After the first round of optimizations, the partial runtime was reduced by a factor of 23; however, performance gains are dependent on the size of the data, the number of processors requested, and the computer used.
Solar Collector Design Optimization: A Hands-on Project Case Study
Birnie, Dunbar P., III; Kaz, David M.; Berman, Elena A.
2012-01-01
A solar power collector optimization design project has been developed for use in undergraduate classrooms and/or laboratories. The design optimization depends on understanding the current-voltage characteristics of the starting photovoltaic cells as well as how the cell's electrical response changes with increased light illumination. Students…
Solar Collector Design Optimization: A Hands-on Project Case Study
Birnie, Dunbar P., III; Kaz, David M.; Berman, Elena A.
2012-01-01
A solar power collector optimization design project has been developed for use in undergraduate classrooms and/or laboratories. The design optimization depends on understanding the current-voltage characteristics of the starting photovoltaic cells as well as how the cell's electrical response changes with increased light illumination. Students…
Tsang, C. F.
2003-12-01
The international cooperative project DECOVALEX (acronym for DEvelopment of COupled THM models and their VALidation against EXperiments) was established in 1992 by national agencies involved in nuclear waste disposal. The aim of this project is to develop and test models capable of simulating coupled thermo-hydro-mechanical (THM) processes. Over the last ten years, about 16 research teams from 10 countries have participated in this joint effort. The project objectives include: a. support development of computer simulators for THM modeling; b. investigate and implement suitable algorithms for THM modeling; c. compare model calculations with results from field and laboratory experiments; d. design new experiments to support code development; e. study the application of THM modeling to performance and safety assessment. A large number of benchmark tests (BMT) and test cases (TC) have been studied within the project. BMTs are hypothetical problems used for investigating the behavior of individual coupled THM processes, using alternative conceptual and numerical models by different teams. TCs are laboratory and field experiments that were analyzed to advance our understanding of THM processes and whose data were used to test computer models. A number of large-scale, multiyear experiments have been studied within the project, including: a. multiple borehole tests for shaft excavation design at Sellafield, UK; b. THM experiment on the bentonite-rock system at Kamaishi Mine, Japan; c. full scale bentonite-rock test (FEBEX) at Grimsel Underground Research Laboratory, Switzerland; d. Drift Scale Heater Test (DST) in the Exploratory Studies Facility at Yucca Mountain, USA. The talk will present an overview of the ten-year project by highlighting a few of the main results and lessons learned.
European project HOPE (Health Optimization Protocol for Energy-efficient Buildings)
Bluyssen, P.M.; Cox, C.W.J.; Maroni, M.; Boschi, N.; Raw, G.; Roulet, C.A.; Foradini, F.
2003-01-01
In January 2002, a new European project named HOPE (Health Optimization Protocol for Energy-efficient Buildings) started with 14 participants from nine European countries. The final goal of the project is to provide the means to increase the number of energy-efficient buildings, i.e. buildings that
European project HOPE (Health Optimization Protocol for Energy-efficient Buildings)
Bluyssen, P.M.; Cox, C.W.J.; Maroni, M.; Boschi, N.; Raw, G.; Roulet, C.A.; Foradini, F.
2003-01-01
In January 2002, a new European project named HOPE (Health Optimization Protocol for Energy-efficient Buildings) started with 14 participants from nine European countries. The final goal of the project is to provide the means to increase the number of energy-efficient buildings, i.e. buildings that
2017-01-01
This work focuses on the design of transmitting coils in weakly coupled magnetic induction communication systems. We propose several optimization methods that reduce the active, reactive and apparent power consumption of the coil. These problems are formulated as minimization problems, in which the power consumed by the transmitting coil is minimized, under the constraint of providing a required magnetic field at the receiver location. We develop efficient numeric and analytic methods to solve the resulting problems, which are of high dimension, and in certain cases non-convex. For the objective of minimal reactive power an analytic solution for the optimal current distribution in flat disc transmitting coils is provided. This problem is extended to general three-dimensional coils, for which we develop an expression for the optimal current distribution. Considering the objective of minimal apparent power, a method is developed to reduce the computational complexity of the problem by transforming it to an equivalent problem of lower dimension, allowing a quick and accurate numeric solution. These results are verified experimentally by testing a number of coil geometries. The results obtained allow reduced power consumption and increased performances in magnetic induction communication systems. Specifically, for wideband systems, an optimal design of the transmitter coil reduces the peak instantaneous power provided by the transmitter circuitry, and thus reduces its size, complexity and cost. PMID:28192463
Harmonizing and Optimizing Fish Testing Methods: The OECD Framework Project
The Organisation for Economic Cooperation and Development (OECD) serves a key role in the international harmonization of testing of a wide variety of chemicals. An integrated fish testing framework project was initiated in mid-2009 through the OECD with the US as the lead country...
Optimizing integrated reference cases in the OCTAVIUS project
Kvamsdal, Hanne M.; Ehlers, Sören; Kather, Alfons
2016-01-01
Adding a carbon capture plant to a power plant reduces the efficiency of said power plant. In order to keep this drop in efficiency as small as possible, several optimisation studies are performed in the OCTAVIUS project. Based on the work of the European Benchmarking Task Force-EBTF within...
Optimizing integrated reference cases in the OCTAVIUS project
Kvamsdal, H.M.; Ehlers, S.; Kather, A.; Khakharia, P.M.; Nienoord, M.; Fosbøl, P.L.
2016-01-01
Adding a carbon capture plant to a power plant reduces the efficiency of said power plant. In order to keep this drop in efficiency as small as possible, several optimisation studies are performed in the OCTAVIUS project. Based on the work of the European Benchmarking Task Force-EBTF within the
Optimizing integrated reference cases in the OCTAVIUS project
Kvamsdal, H.M.; Ehlers, S.; Kather, A.; Khakharia, P.M.; Nienoord, M.; Fosbøl, P.L.
2016-01-01
Adding a carbon capture plant to a power plant reduces the efficiency of said power plant. In order to keep this drop in efficiency as small as possible, several optimisation studies are performed in the OCTAVIUS project. Based on the work of the European Benchmarking Task Force-EBTF within the CESA
Machine coolant waste reduction by optimizing coolant life. Project summary
Pallansch, J.
1995-08-01
The project was designed to study the following: A specific water-soluble coolant (Blasocut 2000 Universal) in use with a variety of machines, tools, and materials; Coolant maintenance practices associated with three types of machines; Health effects of use and handling of recycled coolant; Handling practices for chips and waste coolant; Chip/coolant separation; and Oil/water separation.
Yannibelli, Virginia; Amandi, Analía
2013-01-01
In this article, the project scheduling problem is addressed in order to assist project managers at the early stage of scheduling. Thus, as part of the problem, two priority optimization objectives for managers at that stage are considered. One of these objectives is to assign the most effective set of human resources to each project activity. The effectiveness of a human resource is considered to depend on its work context. The other objective is to minimize the project makespan. To solve the problem, a multi-objective evolutionary algorithm is proposed. This algorithm designs feasible schedules for a given project and evaluates the designed schedules in relation to each objective. The algorithm generates an approximation to the Pareto set as a solution to the problem. The computational experiments carried out on nine different instance sets are reported.
Zoric, Nenad; Livshits, Irina; Dilworth, Don; Okishev, Sergey
2017-02-01
This paper describes a method for designing an ultraviolet (UV) projection lens for microlithography. Our approach for meeting this objective is to use a starting design automatically obtained by the DSEARCH feature in the SYNOPSYS™ lens design program. We describe the steps for getting a desired starting point for the projection lens and discuss optimization problems unique to this system, where the two parts of the projection lens are designed independently.
Wu, Xiangjun; Lu, Hongtao
2010-08-01
In this Letter, generalized projective synchronization (GPS) between two different complex dynamical networks with delayed coupling is investigated. Two complex networks are distinct if they have diverse node dynamics, or different number of nodes, or different topological structures. By using the adaptive control scheme, a sufficient synchronization criterion for this GPS is derived based on the LaSalle invariance principle. Three corollaries are also obtained. It is noticed that the synchronization speed sensitively depends on the adjustable positive constants μ. Furthermore, the coupling configuration matrix is not necessary to be symmetric or irreducible, and the inner coupling matrix need not be symmetric. In addition, the node dynamic need not satisfy the very strong and conservative uniformly Lipschitz condition. Numerical simulations further demonstrate the feasibility and effectiveness of the theoretical results.
Wu Xiangjun, E-mail: wuhsiang@yahoo.c [Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Institute of Complex Intelligent Network System, Henan University, Kaifeng 475004 (China); Computing Center, Henan University, Kaifeng 475004 (China); Lu Hongtao [Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)
2010-08-23
In this Letter, generalized projective synchronization (GPS) between two different complex dynamical networks with delayed coupling is investigated. Two complex networks are distinct if they have diverse node dynamics, or different number of nodes, or different topological structures. By using the adaptive control scheme, a sufficient synchronization criterion for this GPS is derived based on the LaSalle invariance principle. Three corollaries are also obtained. It is noticed that the synchronization speed sensitively depends on the adjustable positive constants {mu}{sub i}. Furthermore, the coupling configuration matrix is not necessary to be symmetric or irreducible, and the inner coupling matrix need not be symmetric. In addition, the node dynamic need not satisfy the very strong and conservative uniformly Lipschitz condition. Numerical simulations further demonstrate the feasibility and effectiveness of the theoretical results.
A Bi-Projection Neural Network for Solving Constrained Quadratic Optimization Problems.
Xia, Youshen; Wang, Jun
2016-02-01
In this paper, a bi-projection neural network for solving a class of constrained quadratic optimization problems is proposed. It is proved that the proposed neural network is globally stable in the sense of Lyapunov, and the output trajectory of the proposed neural network will converge globally to an optimal solution. Compared with existing projection neural networks (PNNs), the proposed neural network has a very small model size owing to its bi-projection structure. Furthermore, an application to data fusion shows that the proposed neural network is very effective. Numerical results demonstrate that the proposed neural network is much faster than the existing PNNs.
Sumata, H.; Kauker, F.; Gerdes, R.; Köberle, C.; Karcher, M.
2012-11-01
Two types of optimization methods were applied to a parameter optimization problem in a coupled ocean-sea ice model, and applicability and efficiency of the respective methods were examined. One is a finite difference method based on a traditional gradient descent approach, while the other adopts genetic algorithms as an example of stochastic approaches. Several series of parameter optimization experiments were performed by minimizing a cost function composed of model-data misfit of ice concentration, ice drift velocity and ice thickness. The finite difference method fails to estimate optimal parameters due to an ill-shaped nature of the cost function, whereas the genetic algorithms can effectively estimate near optimal parameters with a practical number of iterations. The results of the study indicate that a sophisticated stochastic approach is of practical use to a parameter optimization of a coupled ocean-sea ice model.
Optimal Sizes of Dielectric Microspheres for Cavity QED with Strong Coupling
Buck, J R
2002-01-01
The whispering gallery modes (WGMs) of quartz microspheres are investigated for the purpose of strong coupling between single photons and atoms in cavity quantum electrodynamics (cavity QED). Within our current understanding of the loss mechanisms of the WGMs, the saturation photon number, n, and critical atom number, N, cannot be minimized simultaneously, so that an "optimal" sphere size is taken to be the radius for which the geometric mean, (n x N)^(1/2), is minimized. While a general treatment is given for the dimensionless parameters used to characterize the atom-cavity system, detailed consideration is given to the D2 transition in atomic Cesium (852nm) using fused-silica microspheres, for which the maximum coupling coefficient g/(2*pi)=750MHz occurs for a sphere radius a=3.63microns corresponding to the minimum for n=6.06x10^(-6). By contrast, the minimum for N=9.00x10^(-6) occurs for a sphere radius of a=8.12microns, while the optimal sphere size for which (n x N)^(1/2) is minimized occurs at a=7.83mi...
Characterization of the Transient Response of Coupled Optimization in Multidisciplinary Design
Erich Devendorf
2013-01-01
Full Text Available Time is an asset of critical importance in a multidisciplinary design process and it is desirable to reduce the amount of time spent designing products and systems. Design is an iterative activity and designers consume a significant portion of the product development process negotiating a mutually acceptable solution. The amount of time necessary to complete a design depends on the number and duration of design iterations. This paper focuses on accurately characterizing the number of iterations required for designers to converge to an equilibrium solution in distributed design processes. In distributed design, systems are decomposed into smaller, coupled design problems where individual designers have control over local design decisions and seek to achieve their own individual objectives. These smaller coupled design optimization problems can be modeled using coupled games and the number of iterations required to reach equilibrium solutions varies based on initial conditions and process architecture. In this paper, we leverage concepts from game theory, classical controls, and discrete systems theory to evaluate and approximate process architectures without carrying out any solution iterations. As a result, we develop an analogy between discrete decisions and a continuous time representation that we analyze using control theoretic techniques.
A Projected Lagrangian Algorithm for Nonlinear Minimax Optimization.
1979-11-01
T Problem 5: Charalambous and Bandler (1976) # 1. f 1(x ) 2- + _ f3(x) = 2 exp(-x+ X2) Starting Pointz xO (1,..1)T 61 Problem 6: Rosen and Suzuki...Charalambous and Bandler ,#l) 2 3 1 6 6 6 (Rosen and Suzuki) 4 4 2 7 10 The results demonstrate that at least on a limited set of test problems the...and Numerical Methods for Stiff Differential Equations. Charalambous, C. and J.W. Bandler (1974). Nonlinear minimax optimization as a sequence of least
Limber, Mark A.; Manteuffel, Thomas A.; Mccormick, Stephen F.; Sholl, David S.
1993-01-01
We consider the problem of image reconstruction from a finite number of projections over the space L(sup 1)(Omega), where Omega is a compact subset of the set of Real numbers (exp 2). We prove that, given a discretization of the projection space, the function that generates the correct projection data and maximizes the Boltzmann-Shannon entropy is piecewise constant on a certain discretization of Omega, which we call the 'optimal grid'. It is on this grid that one obtains the maximum resolution given the problem setup. The size of this grid grows very quickly as the number of projections and number of cells per projection grow, indicating fast computational methods are essential to make its use feasible. We use a Fenchel duality formulation of the problem to keep the number of variables small while still using the optimal discretization, and propose a multilevel scheme to improve convergence of a simple cyclic maximization scheme applied to the dual problem.
Optimization of a hardware implementation for pulse coupled neural networks for image applications
Gimeno Sarciada, Jesús; Lamela Rivera, Horacio; Warde, Cardinal
2010-04-01
Pulse Coupled Neural Networks are a very useful tool for image processing and visual applications, since it has the advantages of being invariant to image changes as rotation, scale, or certain distortion. Among other characteristics, the PCNN changes a given image input into a temporal representation which can be easily later analyzed for pattern recognition. The structure of a PCNN though, makes it necessary to determine all of its parameters very carefully in order to function optimally, so that the responses to the kind of inputs it will be subjected are clearly discriminated allowing for an easy and fast post-processing yielding useful results. This tweaking of the system is a taxing process. In this paper we analyze and compare two methods for modeling PCNNs. A purely mathematical model is programmed and a similar circuital model is also designed. Both are then used to determine the optimal values of the several parameters of a PCNN: gain, threshold, time constants for feed-in and threshold and linking leading to an optimal design for image recognition. The results are compared for usefulness, accuracy and speed, as well as the performance and time requirements for fast and easy design, thus providing a tool for future ease of management of a PCNN for different tasks.
Wang, Zhichao; Li, Qingyong; Zhao, Xiuhua; Sun, Baihe; Zhu, Qiaochu; Gao, Wenqing; Hua, Changlong
2014-04-25
The purpose of this work is to prepare a formulation using mannitol coupling Camptothecin (CPT) nanoparticles (CPT-NPs) to circumvent the difficult solubilization practice based on central composite experimental statistical design. CPT-NPs were prepared with a high-pressure homogenization technique method. The independent variables considered for the optimization of CPT-NPs were percentage of CPT in raw material (CPT and mannitol), concentration of CPT in working liquid, cycles numbers and homogenizer pressure for drug loading efficiency, particle size and polydispersity index. Analysis of variance (ANOVA) statistical test was used to assess the optimization. The optimized CPT-NPs showed an appropriate drug loading efficiency (18.09 ± 2.13%), a homogeneous particle size (165.33 ± 37.23 nm) and a low polydispersity index (0.29 ± 0.01). The CPT-NPs group show higher inhibition ratio (79.95%) of H22 tumor growth in vivo compared with TPT and CPT at the same dose. Changes in mice body weight demonstrate CPT-NPs have the lower toxicity. The results of biodistribution studies indicated the obviously superiority of CPT-NPs in increasing the accumulation of CPT within tumor. Overall, CPT-NPs under optimum conditions are considered to be potentially feasible to overcome formulation challenges for drug delivery.
S. Prabhu
2014-06-01
Full Text Available Carbon nanotube (CNT mixed grinding wheel has been used in the electrolytic in-process dressing (ELID grinding process to analyze the surface characteristics of AISI D2 Tool steel material. CNT grinding wheel is having an excellent thermal conductivity and good mechanical property which is used to improve the surface finish of the work piece. The multiobjective optimization of grey relational analysis coupled with principal component analysis has been used to optimize the process parameters of ELID grinding process. Based on the Taguchi design of experiments, an L9 orthogonal array table was chosen for the experiments. The confirmation experiment verifies the proposed that grey-based Taguchi method has the ability to find out the optimal process parameters with multiple quality characteristics of surface roughness and metal removal rate. Analysis of variance (ANOVA has been used to verify and validate the model. Empirical model for the prediction of output parameters has been developed using regression analysis and the results were compared for with and without using CNT grinding wheel in ELID grinding process.
3-D carotid multi-region MRI segmentation by globally optimal evolution of coupled surfaces.
Ukwatta, Eranga; Yuan, Jing; Rajchl, Martin; Qiu, Wu; Tessier, David; Fenster, Aaron
2013-04-01
In this paper, we propose a novel global optimization based 3-D multi-region segmentation algorithm for T1-weighted black-blood carotid magnetic resonance (MR) images. The proposed algorithm partitions a 3-D carotid MR image into three regions: wall, lumen, and background. The algorithm performs such partitioning by simultaneously evolving two coupled 3-D surfaces of carotid artery adventitia boundary (AB) and lumen-intima boundary (LIB) while preserving their anatomical inter-surface consistency such that the LIB is always located within the AB. In particular, we show that the proposed algorithm results in a fully time implicit scheme that propagates the two linearly ordered surfaces of the AB and LIB to their globally optimal positions during each discrete time frame by convex relaxation. In this regard, we introduce the continuous max-flow model and prove its duality/equivalence to the convex relaxed optimization problem with respect to each evolution step. We then propose a fully parallelized continuous max-flow-based algorithm, which can be readily implemented on a GPU to achieve high computational efficiency. Extensive experiments, with four users using 12 3T MR and 26 1.5T MR images, demonstrate that the proposed algorithm yields high accuracy and low operator variability in computing vessel wall volume. In addition, we show the algorithm outperforms previous methods in terms of high computational efficiency and robustness with fewer user interactions.
Zhang, Guannan; Schilling, Franz; Glaser, Steffen J.; Hilty, Christian
2016-11-01
Off-resonance decoupling using the method of Scaling of Heteronuclear Couplings by Optimal Tracking (SHOT) enables determination of heteronuclear correlations of chemical shifts in single scan NMR spectra. Through modulation of J-coupling evolution by shaped radio frequency pulses, off resonance decoupling using SHOT pulses causes a user-defined dependence of the observed J-splitting, such as the splitting of 13C peaks, on the chemical shift offset of coupled nuclei, such as 1H. Because a decoupling experiment requires only a single scan, this method is suitable for characterizing on-going chemical reactions using hyperpolarization by dissolution dynamic nuclear polarization (D-DNP). We demonstrate the calculation of [13C, 1H] chemical shift correlations of the carbanionic active sites from hyperpolarized styrene polymerized using sodium naphthalene as an initiator. While off resonance decoupling by SHOT pulses does not enhance the resolution in the same way as a 2D NMR spectrum would, the ability to obtain the correlations in single scans makes this method ideal for determination of chemical shifts in on-going reactions on the second time scale. In addition, we present a novel SHOT pulse that allows to scale J-splittings 50% larger than the respective J-coupling constant. This feature can be used to enhance the resolution of the indirectly detected chemical shift and reduce peak overlap, as demonstrated in a model reaction between p-anisaldehyde and isobutylamine. For both pulses, the accuracy is evaluated under changing signal-to-noise ratios (SNR) of the peaks from reactants and reaction products, with an overall standard deviation of chemical shift differences compared to reference spectra of 0.02 ppm when measured on a 400 MHz NMR spectrometer. Notably, the appearance of decoupling side-bands, which scale with peak intensity, appears to be of secondary importance.
The economics of project analysis: Optimal investment criteria and methods of study
Scriven, M. C.
1979-01-01
Insight is provided toward the development of an optimal program for investment analysis of project proposals offering commercial potential and its components. This involves a critique of economic investment criteria viewed in relation to requirements of engineering economy analysis. An outline for a systems approach to project analysis is given Application of the Leontief input-output methodology to analysis of projects involving multiple processes and products is investigated. Effective application of elements of neoclassical economic theory to investment analysis of project components is demonstrated. Patterns of both static and dynamic activity levels are incorporated.
Optimization of an Efficient and Sustainable Sonogashira Cross-Coupling Protocol
Walter, Philipp E.
2012-12-01
Cross coupling reactions are a well-established tool in modern organic synthesis and play a crucial role in the synthesis of a high number of organic compounds. Their importance is highlighted by the Nobel Prize in chemistry to Suzuki, Heck and Negishi in 2010. The increasing importance of sustainability requirements in chemical production has furthermore promoted the development of cross-coupling protocols that comply with the principles of “Green Chemistry”1. The Sonogashira reaction is today the most versatile and powerful way to generate aryl alkynes, a moiety recurring in many pharmaceutical and natural products. Despite many improvements to the original reaction, reports on generally applicable protocols that work under sustainable conditions are scarce. Our group recently reported an efficient protocol for a copperfree Sonogashira cross-coupling at low temperature, in aqueous medium and with no addition of organic solvents or additives2. The goal of this work was to further investigate the effects of different reaction parameters on the catalytic activity in order to optimize the protocol. Limitations of the protocol were tested in respect to reaction temperature, heating method, atmosphere, base type and amount, catalyst loading, reaction time and work up procedure. The reaction worked successfully under air and results were not affected by the presence of oxygen in the water phase. Among a variety of bases tested, triethylamine was confirmed to give the best results and its required excess could be reduced from nine to four equivalents. Catalyst loading could also be reduced by up to 90%: Good to near quantitative yields for a broad range of substrates were achieved using a catalyst concentration of 0.25mol% and 5 eq of Et3N at 50°C while more reactive substrates could be coupled with a catalyst concentration as low as 0.025mol%. Filtration experiments showed the possibility of a simplified work up procedure and a protocol completely free of organic
TIAN Ye-sheng;LI Hu-lin;JIANG Yong-yue;LONG Lei;JI Yong-zhe;ZHOU Jian-yue
2016-08-01
Full Text Available A coupling optimization design and experimental study method with uniform experimental and Aspen process simulation was established in this paper, which was used for stable isotope 13C separation of the double-stage cascade. Based on the above method, the optimization operating parameters were received. The coupling optimization simulation value showed good agreement with the experimental dates, and the average relative error was only 6.5%. On the other hand, compared with the initial test result, the 13C abundance of optimized experimental was 14.1%, and the actual growth rate of 13C abundance was more than 25%. More importantly, The optimization experimental did not increase energy consumption. The method confirmed by the experiment could provide a solid foundation for the cascade process of 13C industrialization, and it could also be applied to other traditional distillation industry.
An actuator line model simulation with optimal body force projection length scales
Martinez-Tossas, Luis; Churchfield, Matthew J.; Meneveau, Charles
2016-11-01
In recent work (Martínez-Tossas et al. "Optimal smoothing length scale for actuator line models of wind turbine blades", preprint), an optimal body force projection length-scale for an actuator line model has been obtained. This optimization is based on 2-D aerodynamics and is done by comparing an analytical solution of inviscid linearized flow over a Gaussian body force to the potential flow solution of flow over a Joukowski airfoil. The optimization provides a non-dimensional optimal scale ɛ / c for different Joukowski airfoils, where ɛ is the width of the Gaussian kernel and c is the chord. A Gaussian kernel with different widths in the chord and thickness directions can further reduce the error. The 2-D theory developed is extended by simulating a full scale rotor using the optimal body force projection length scales. Using these values, the tip losses are captured by the LES and thus, no additional explicit tip-loss correction is needed for the actuator line model. The simulation with the optimal values provides excellent agreement with Blade Element Momentum Theory. This research is supported by the National Science Foundation (Grant OISE-1243482, the WINDINSPIRE project).
Optimizing the Time Performance of Subcontractors in Building Projects
Andy K.W Ng
2010-07-01
Full Text Available The main contractors of Hong Kong building projects tend to subcontract most of their work. However, many of the subcontractors complain that they are not being fully utilized due main contractors’ poor site coordination of temporary works and interfacing works and plant supports etc. A list of critical site coordination problems caused by main contractors that had adversely influence to the time performance of subcontractors was prepared. A questionnaire survey was conducted to collect data to generate multiple regression equations that explain how the critical site coordination problems affected the time performance of different types of subcontractor. The survey results were validated by neural network analysis. Backward elimination method was adopted to identify the ‘most critical’ site coordination problems that enable main contractors to formulate measures to enhance their site management system.
Optimizing the Time Performance of Subcontractors in Building Projects
Andrew D.F Price
2010-07-01
Full Text Available The main contractors of Hong Kong building projects tend to subcontract most of their work. However, many of the subcontractors complain that they are not being fully utilized due main contractors’ poor site coordination of temporary works and interfacing works and plant supports etc. A list of critical site coordination problems caused by main contractors that had adversely influence to the time performance of subcontractors was prepared. A questionnaire survey was conducted to collect data to generate multiple regression equations that explain how the critical site coordination problems affected the time performance of different types of subcontractor. The survey results were validated by neural network analysis. Backward elimination method was adopted to identify the ‘most critical’ site coordination problems that enable main contractors to formulate measures to enhance their site management system.
Optimizing care in osteoporosis: The Canadian quality circle project
Kvern Brent
2008-10-01
Full Text Available Abstract Background While the Osteoporosis Canada 2002 Canadian guidelines provided evidence based strategies in preventing, diagnosing, and managing this condition, publication and distribution of guidelines have not, in and of themselves, been shown to alter physicians clinical approaches. We hypothesize that primary care physicians enrolled in the Quality Circle project would change their patient management of osteoporosis in terms of awareness of osteoporosis risk factors and bone mineral density testing in accordance with the guidelines. Methods The project consisted of five Quality Circle phases that included: 1 Training & Baseline Data Collection, 2 First Educational Intervention & First Follow-Up Data Collection 3 First Strategy Implementation Session, 4 Final Educational Intervention & Final Follow-up Data Collection, and 5 Final Strategy Implementation Session. A total of 340 circle members formed 34 quality circles and participated in the study. The generalized estimating equations approach was used to model physician awareness of risk factors for osteoporosis and appropriate utilization of bone mineral density testing pre and post educational intervention (first year of the study. Odds ratios (OR and 95% confidence intervals (95% CI were calculated. Results After the 1st year of the study, physicians' certainty of their patients' risk factor status increased. Certainty varied from an OR of 1.4 (95% CI: 1.1, 1.8 for prior vertebral fracture status to 6.3 (95% CI: 2.3, 17.9 for prior hip fracture status. Furthermore, bone mineral density testing increased in high risk as compared with low risk patients (OR: 1.4; 95% CI: 1.2, 1.7. Conclusion Quality Circle methodology was successful in increasing both physicians' awareness of osteoporosis risk factors and appropriate bone mineral density testing in accordance with the 2002 Canadian guidelines.
Xiaoping Bai
2013-01-01
Full Text Available The structure of the construction project logistics system is decomposed in detail; some uncertain factors affecting system reliability are analyzed. This paper applies the probability-influence coordinate graph to screen out the logistics subsystem that has great influence on system reliability under the conditions of occurring failure, and establishes an allocation model of the reliability index in construction project logistics system based on the restriction of cost, makes use of the presented model and algorithm to calculate the cost-based reliability, contrasts it with the index reliability assigned by the scoring method to the optimal distribution value of reliability index and the optimal cost. The presented detailed methods and steps can offer the meaningful reference for reliability optimization management of the logistics system in the construction project.
Horizontal ground coupled heat pump: Thermal-economic modeling and optimization
Sanaye, Sepehr; Niroomand, Behzad [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST) (Iran)
2010-12-15
The modeling and optimizing processes of a Ground Coupled Heat Pump (GCHP) with closed Horizontal Ground Heat eXchanger (HGHX) are presented in this paper. After thermal modeling of GCHP including HGHX, the optimum design parameters of the system were estimated by minimizing a defined objective function (total of investment and operation costs) subject to a list of constraints. This procedure was performed applying Genetic Algorithm technique. For given heating/cooling loads and various climatic conditions, the optimum values of saturated temperature/pressure of condenser and evaporator as well as inlet and outlet temperatures of the water source in cooling and heating modes were predicted. Then, for our case study, the design parameters as well as the configuration of HGHX were obtained. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, and soil type were discussed. (author)
Liu Jianghua(刘江华); Chen Jiapin; Cheng Junshi
2004-01-01
Coupled Hidden Markov Model (CHMM) is the extension of traditional HMM, which is mainly used for complex interactive process modeling such as two-hand gestures. However, the problems of finding optimal model parameter are still of great interest to the researches in this area. This paper proposes a hybrid genetic algorithm (HGA) for the CHMM training. Chaos is used to initialize GA and used as mutation operator. Experiments on Chinese TaiChi gestures show that standard GA (SGA) based CHMM training is superior to Maximum Likelihood (ML) HMM training. HGA approach has the highest recognition rate of 98.0769%, then 96.1538% for SGA. The last one is ML method, only with a recognition rate of 69.2308%.
Optimizing investments in coupled offshore wind -electrolytic hydrogen storage systems in Denmark
Hou, Peng; Enevoldsen, Peter; Eichman, Joshua; Hu, Weihao; Jacobson, Mark Z.; Chen, Zhe
2017-08-01
In response to electricity markets with growing levels of wind energy production and varying electricity prices, this research examines incentives for investments in integrated renewable energy power systems. A strategy for using optimization methods for a power system consisting of wind turbines, electrolyzers, and hydrogen fuel cells is explored. This research reveals the investment potential of coupling offshore wind farms with different hydrogen systems. The benefits in terms of a return on investment are demonstrated with data from the Danish electricity markets. This research also investigates the tradeoffs between selling the hydrogen directly to customers or using it as a storage medium to re-generate electricity at a time when it is more valuable. This research finds that the most beneficial configuration is to produce hydrogen at a time that complements the wind farm and sell the hydrogen directly to end users.
Study of Scintillator thickness optimization of lens-coupled X-ray imaging detectors
Xie, H.; Du, G.; Deng, B.; Chen, R.; Xiao, T.
2016-03-01
Lens-coupled X-ray in-direct imaging detectors are very popular for high-resolution X-ray imaging at the third generation synchrotron radiation facilities. This imaging system consists of a scintilator producing a visible-light image of X-ray beam, a microscope objective, a mirror reflecting at 90° and a CCD camera. When the thickness of the scintillator is matched with the numerical aperture (NA) of the microscope objective, the image quality of experimental results will be improved obviously. This paper used an imaging system at BL13W beamline of Shanghai Synchrotron Radiation Facility (SSRF) to study the matching relation between the scintillator thickness and the NA of the microscope objective with a real sample. By use of the matching relation between the scintillator thickness and the NA of the microscope objective, the optimal imaging results have been obtained.
Tailored inter and intra layer exchange coupled superlattices for optimized magnetocaloric effect
Mukherjee, Tathagata; Michalski, S.; Skomski, R.; Sellmyer, D. J.; Binek, Ch.
2012-02-01
We explore Magnetocaloric (MC) properties of Fe/Cr superlattices with tailored inter- and intra-layer interaction using simple 3d metals. Our multilayers are fabricated by pulsed-laser deposition with emphasis on maximizing magnetic entropy changes near room temperature. NanostructuringootnotetextT. Mukherjee, S. Sahoo, R. Skomski, D. J. Sellmyer, and Ch. Binek, Phys. Rev. B 79, 144406 (2009). allows tailoring ferromagnetic and antiferromagnetic coupling. This in concert with finite size scaling of the ferromagnetic Fe films has the potential to lead to optimized MC materials. Thermodynamic and MC properties of such Fe/Cr superlattices are studied with the help of SQUID magnetometry. Entropy changes are deduced via the Maxwell relation in single phase regions, X-ray diffraction and X-ray reflectivity are used to correlate structural data with the magnetic properties.
Stebbings, S L; Suessmann, F; Yang, Y-Y; Kling, M F [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strass e 1, 85748 Garching (Germany); Scrinzi, A [Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, 80333 Muenchen (Germany); Durach, M; Rusina, A; Stockman, M I, E-mail: sarah.stebbings@mpq.mpg.de, E-mail: mstockman@gsu.edu, E-mail: matthias.kling@mpq.mpg.de [Department of Physics and Astronomy, Georgia State University, 29 Peachtree Center Avenue, Atlanta, GA 30303 (United States)
2011-07-15
The production of extreme ultraviolet (XUV) radiation via nanoplasmonic field-enhanced high-harmonic generation (HHG) in gold nanostructures at MHz repetition rates is investigated theoretically in this paper. Analytical and numerical calculations are employed and compared in order to determine the plasmonic fields in gold ellipsoidal nanoparticles. The comparison indicates that numerical calculations can accurately predict the field enhancement and plasmonic decay, but may encounter difficulties when attempting to predict the oscillatory behavior of the plasmonic field. Numerical calculations for coupled symmetric and asymmetric ellipsoids for different carrier-envelope phases (CEPs) of the driving laser field are combined with time-dependent Schroedinger equation simulations to predict the resulting HHG spectra. The studies reveal that the plasmonic field oscillations, which are controlled by the CEP of the driving laser field, play a more important role than the nanostructure configuration in finding the optimal conditions for the generation of isolated attosecond XUV pulses via nanoplasmonic field enhancement.
Stebbings, S. L.; Süßmann, F.; Yang, Y.-Y.; Scrinzi, A.; Durach, M.; Rusina, A.; Stockman, M. I.; Kling, M. F.
2011-07-01
The production of extreme ultraviolet (XUV) radiation via nanoplasmonic field-enhanced high-harmonic generation (HHG) in gold nanostructures at MHz repetition rates is investigated theoretically in this paper. Analytical and numerical calculations are employed and compared in order to determine the plasmonic fields in gold ellipsoidal nanoparticles. The comparison indicates that numerical calculations can accurately predict the field enhancement and plasmonic decay, but may encounter difficulties when attempting to predict the oscillatory behavior of the plasmonic field. Numerical calculations for coupled symmetric and asymmetric ellipsoids for different carrier-envelope phases (CEPs) of the driving laser field are combined with time-dependent Schrödinger equation simulations to predict the resulting HHG spectra. The studies reveal that the plasmonic field oscillations, which are controlled by the CEP of the driving laser field, play a more important role than the nanostructure configuration in finding the optimal conditions for the generation of isolated attosecond XUV pulses via nanoplasmonic field enhancement.
A Novel Optimization Means of Transfer Efficiency for Resonance Coupled Wireless Power Transfer
Tan Linlin
2013-05-01
Full Text Available When the transmitting and receiving coils are equivalent with or not significantly smaller than their separation distance between the two coils, the results of numerical simulations for transfer efficiency of system show that the maximum coupling of two coils or maximum transfer efficiency occur with a certain tilt angle between two coils, which means the two coils with parallel on the same axis is not able to obtain the maximum transmission efficiency. In view of this feature of the wireless power transfer system, we propose a novel means to optimize the transfer efficiency by designing rotatable transmitting coils to achieve the appropriate tile angle. The experimental results show that the presented means is efficient and greatly improves the transfer efficiency.
Davidsen, Claus; Liu, Suxia; Mo, Xingguo
2015-01-01
for pre-treatment of the water before use. Similarly, treatment of the return flow can reduce the BOD load to the river. A traditional SDP approach is used to solve one-step-ahead sub-problems for all combinations of discrete reservoir storage, Markov Chain inflow clas-ses and monthly time steps...... and customizable method. The method has been applied to the Ziya River basin, an economic hotspot located on the North China Plain in Northern China. The basin is subject to severe water scarcity, and the rivers are heavily polluted with wastewater and nutrients from diffuse sources. The coupled hydro......-economic optimiza-tion model can be used to assess costs of meeting additional constraints such as minimum water qual-ity or to economically prioritize investments in waste water treatment facilities based on economic criteria....
Optimizing insulin pump therapy: a quality improvement project.
Meade, Lisa T; Rushton, Wanda E
2013-01-01
The purpose of the study was to assess insulin pump use and provide ongoing education. A quality improvement project using a pump assessment questionnaire was implemented at an endocrinology office in the southeastern United States. The questionnaire was designed to evaluate all aspects of insulin pump therapy, including pump operations, infusion set failure, management of acute complications, and usage of advanced device features. Eighty-nine patients (80% with type 1 diabetes and 20% with type 2 diabetes) completed the questionnaire at the endocrinology practice. A certified diabetes educator reviewed the questions with each patient, identifying deficiencies and training opportunities. The most common areas of deficiency identified after implementation of the assessment form included the following: expired or no basal insulin prescription in the event of pump failure or removal, no mupirocin (Bactroban®, GlaxoSmithKline, Research Triangle Park, North Carolina) prescription for suspected site infections, lack of insulin syringe if pump stopped working, failure to check urine ketones, no antiemetic prescription for sick day intervention, using manual bolus instead of bolus calculator, and lack of in-date glucagon kit. Use of a pump assessment questionnaire allows for focused discussion concerning patient behaviors related to pump operations, troubleshooting, and self-management. Incorporating use of a pump assessment questionnaire into routine practice may result in improved patient education and avoidance of adverse events specific to insulin pump therapy.
A projection method for under determined optimal experimental designs
Long, Quan
2014-01-09
A new implementation, based on the Laplace approximation, was developed in (Long, Scavino, Tempone, & Wang 2013) to accelerate the estimation of the post–experimental expected information gains in the model parameters and predictive quantities of interest. A closed–form approximation of the inner integral and the order of the corresponding dominant error term were obtained in the cases where the parameters are determined by the experiment. In this work, we extend that method to the general cases where the model parameters could not be determined completely by the data from the proposed experiments. We carry out the Laplace approximations in the directions orthogonal to the null space of the corresponding Jacobian matrix, so that the information gain (Kullback–Leibler divergence) can be reduced to an integration against the marginal density of the transformed parameters which are not determined by the experiments. Furthermore, the expected information gain can be approximated by an integration over the prior, where the integrand is a function of the projected posterior covariance matrix. To deal with the issue of dimensionality in a complex problem, we use Monte Carlo sampling or sparse quadratures for the integration over the prior probability density function, depending on the regularity of the integrand function. We demonstrate the accuracy, efficiency and robustness of the proposed method via several nonlinear under determined numerical examples.
Optimized acquisition scheme for multi-projection correlation imaging of breast cancer
Chawla, Amarpreet S.; Samei, Ehsan; Saunders, Robert S.; Lo, Joseph Y.; Singh, Swatee
2008-03-01
We are reporting the optimized acquisition scheme of multi-projection breast Correlation Imaging (CI) technique, which was pioneered in our lab at Duke University. CI is similar to tomosynthesis in its image acquisition scheme. However, instead of analyzing the reconstructed images, the projection images are directly analyzed for pathology. Earlier, we presented an optimized data acquisition scheme for CI using mathematical observer model. In this article, we are presenting a Computer Aided Detection (CADe)-based optimization methodology. Towards that end, images from 106 subjects recruited for an ongoing clinical trial for tomosynthesis were employed. For each patient, 25 angular projections of each breast were acquired. Projection images were supplemented with a simulated 3 mm 3D lesion. Each projection was first processed by a traditional CADe algorithm at high sensitivity, followed by a reduction of false positives by combining geometrical correlation information available from the multiple images. Performance of the CI system was determined in terms of free-response receiver operating characteristics (FROC) curves and the area under ROC curves. For optimization, the components of acquisition such as the number of projections, and their angular span were systematically changed to investigate which one of the many possible combinations maximized the sensitivity and specificity. Results indicated that the performance of the CI system may be maximized with 7-11 projections spanning an angular arc of 44.8°, confirming our earlier findings using observer models. These results indicate that an optimized CI system may potentially be an important diagnostic tool for improved breast cancer detection.
Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators
Sadeque Reza Khan
2016-08-01
Full Text Available High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8% than circular resonators (78.43% when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW to the load than the square coils (396 mW under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation.
Hongjun Li
2012-01-01
Full Text Available This paper proposes a modified particle swarm optimization algorithm coupled with the finite element limit equilibrium method (FELEM for the minimum factor of safety and the location of associated noncircular critical failure surfaces for various geotechnical practices. During the search process, the stress compatibility constraints coupled with the geometrical and kinematical compatibility constraints are firstly established based on the features of slope geometry and stress distribution to guarantee realistic slip surfaces from being unreasonable. Furthermore, in the FELEM, based on rigorous theoretical analyses and derivation, it is noted that the physical meaning of the factor of safety can be formulated on the basis of strength reserving theory rather than the overloading theory. Consequently, compared with the limit equilibrium method (LEM and the shear strength reduction method (SSRM through several numerical examples, the FELEM in conjunction with the improved search strategy is proved to be an effective and efficient approach to routine analysis and design in geotechnical practices with a high level of confidence.
Shan, Bonan; Wang, Jiang; Deng, Bin; Zhang, Zhen; Wei, Xile
2017-03-01
Assessment of the effective connectivity among different brain regions during seizure is a crucial problem in neuroscience today. As a consequence, a new model inversion framework of brain function imaging is introduced in this manuscript. This framework is based on approximating brain networks using a multi-coupled neural mass model (NMM). NMM describes the excitatory and inhibitory neural interactions, capturing the mechanisms involved in seizure initiation, evolution and termination. Particle swarm optimization method is used to estimate the effective connectivity variation (the parameters of NMM) and the epileptiform dynamics (the states of NMM) that cannot be directly measured using electrophysiological measurement alone. The estimated effective connectivity includes both the local connectivity parameters within a single region NMM and the remote connectivity parameters between multi-coupled NMMs. When the epileptiform activities are estimated, a proportional-integral controller outputs control signal so that the epileptiform spikes can be inhibited immediately. Numerical simulations are carried out to illustrate the effectiveness of the proposed framework. The framework and the results have a profound impact on the way we detect and treat epilepsy.
Optimization of wind speed on dispersion of pollutants using coupled receptor and dispersion model
N Anu; S Rangabhashiyam; Rahul Antony; N Selvaraju
2015-08-01
Air pollutants emission from various source categories can be quantified through mass balance (receptor model) techniques, multivariate data analysis and dispersion model. The composition of particulate matter from various emission points (emission inventory) and the massive analysis of the composition in the collected samples from various locations (receptor) are used to estimate quantitative source contribution through receptor models. In dispersion model, on the other hand the emission rates (g/m3) from various sources together with particle size, stack height, topography, meteorological conditions (temperature, humidity, wind speed and directions, etc.) will affect the pollutant concentration at a point or in a region. The parameters used in dispersion model are not considering in receptor models but have been affecting indirectly as difference concentration at various receptor locations. These differences are attributed and possible erroneous results can be viewed through coupled receptor-dispersion model analysis. The current research work proposed a coupled receptor-dispersion model to reduce the difference between predicted concentrations through optimized wind velocity used in dispersion model. The converged wind velocities for various error percentages (10%, 40%, 60% and 80%) in receptor concentration have been obtained with corresponding increase in the error. The proposed combined approaches help to reconcile the differences arise when the two models used in an individual mode.
Polarization-Dependent Optimization of Fiber-Coupled Terahertz Time-Domain Spectroscopy System
Jing Yang; Shan He; Jia-Yu Zhao; Lan-Jun Guo; Wei-Wei Liu
2015-01-01
Abstract¾The optimization of the fiber-coupled terahertz time-domain spectroscopy (THz-TDS) system is performed by changing the polarization of the optical excitation pulse centered at 1550nm. InGaAs/InAlAs multilayer structures based photoconductive antennas are used in TDS setup as both the emitter and receiver. The experimental results demonstrate that not only the THz signal power but also the temporal waveform vary with the rotation of the exciting pulse polarization. Maximum output power of the emitter is obtained when the polarization of the pump pulse is perpendicular to the edge of the metal electrodes. At this moment the THz waveform is close to a single-cycled pulse. However, double THz pulses could be recorded when the pump laser polarization is parallel to the electrodes. Laser pulse splitting induced by the birefringence of the optical fiber may attribute to the polarization- dependent performance of the fiber-coupled THz-TDS system.
Robust Optimization for Time-Cost Tradeoff Problem in Construction Projects
Ming Li
2014-01-01
Full Text Available Construction projects are generally subject to uncertainty, which influences the realization of time-cost tradeoff in project management. This paper addresses a time-cost tradeoff problem under uncertainty, in which activities in projects can be executed in different construction modes corresponding to specified time and cost with interval uncertainty. Based on multiobjective robust optimization method, a robust optimization model for time-cost tradeoff problem is developed. In order to illustrate the robust model, nondominated sorting genetic algorithm-II (NSGA-II is modified to solve the project example. The results show that, by means of adjusting the time and cost robust coefficients, the robust Pareto sets for time-cost tradeoff can be obtained according to different acceptable risk level, from which the decision maker could choose the preferred construction alternative.
QI Shen-jun; DING Lie-yun; LUO Han-bin; DONG Xiao-yan
2007-01-01
Lean construction has been newly applied to construction industry. The best performance of a project can be achieved through the precise definition of construction product, rational work break structure, lean supply chain, decrease of resources waste, objective control and so forth. Referring to the characteristics of schedule planning of construction projects and lean construction philosophy, we proposed optimizing methodology of real-time and dynamic schedule of construction projects based on lean construction. The basis of the methodology is process reorganization and lean supply in construction enterprises. The traditional estimating method of the activity duration is fuzzy and random; however, a newly proposed lean forecasting method employs multi-components linear-regression, back-propagation artificial neural networks and learning curve. Taking account of the limited resources and the fixed duration of a project, the optimizing method of the real-time and dynamic schedule adopts the concept of resource driving. To optimize the schedule of a construction project timely and effectively, an intellectualized schedule management system was developed. It can work out the initial schedule, optimize the real-time and dynamic schedule, and display the schedule with the Gant Chart, the net-work graph and the space-time line chart. A case study was also presented to explain the proposed method.
Genetic algorithm for project time-cost optimization in fuzzy environment
Khan Md. Ariful Haque
2012-12-01
Full Text Available Purpose: The aim of this research is to develop a more realistic approach to solve project time-cost optimization problem under uncertain conditions, with fuzzy time periods. Design/methodology/approach: Deterministic models for time-cost optimization are never efficient considering various uncertainty factors. To make such problems realistic, triangular fuzzy numbers and the concept of a-cut method in fuzzy logic theory are employed to model the problem. Because of NP-hard nature of the project scheduling problem, Genetic Algorithm (GA has been used as a searching tool. Finally, Dev-C++ 4.9.9.2 has been used to code this solver. Findings: The solution has been performed under different combinations of GA parameters and after result analysis optimum values of those parameters have been found for the best solution. Research limitations/implications: For demonstration of the application of the developed algorithm, a project on new product (Pre-paid electric meter, a project under government finance launching has been chosen as a real case. The algorithm is developed under some assumptions. Practical implications: The proposed model leads decision makers to choose the desired solution under different risk levels. Originality/value: Reports reveal that project optimization problems have never been solved under multiple uncertainty conditions. Here, the function has been optimized using Genetic Algorithm search technique, with varied level of risks and fuzzy time periods.
Wei Wang
2015-01-01
Full Text Available This paper presented a parameter estimation method based on a coupled hydromechanical model of dynamic compaction and the Pareto multiobjective optimization technique. The hydromechanical model of dynamic compaction is established in the FEM program LS-DYNA. The multiobjective optimization algorithm, Nondominated Sorted Genetic Algorithm (NSGA-IIa, is integrated with the numerical model to identify soil parameters using multiple sources of field data. A field case study is used to demonstrate the capability of the proposed method. The observed pore water pressure and crater depth at early blow of dynamic compaction are simultaneously used to estimate the soil parameters. Robustness of the back estimated parameters is further illustrated by a forward prediction. Results show that the back-analyzed soil parameters can reasonably predict lateral displacements and give generally acceptable predictions of dynamic compaction for an adjacent location. In addition, for prediction of ground response of the dynamic compaction at continuous blows, the prediction based on the second blow is more accurate than the first blow due to the occurrence of the hardening and strengthening of soil during continuous compaction.
Zhang, Longyun; Yang, Ying; Shi, Zhongping
2008-11-01
The products concentrations in traditional acetone-butanol (AB) fermentation are too low that large amount of energy has to be consumed in the distillation and product recovery process. Aiming at direct utilization of the fermentation products, in this study, optimization of property-improved biodiesel manufacturing process coupled with AB extractive fermentation was conducted, under the condition of using the biodiesel originated from waste cooking oil as the extractant and high concentrated corn flour medium. The effect of biodiesel/broth volume ratio, waste supernatant recycle ratio, and electronic carrier addition on the major process performance index was carefully investigated. Under the optimized condition, the biodiesel quality was improved with the cetane value increased from 51.4 to 54.4; "actual butanol yield" reached to a level of 18%, and waste supernatant recycle ratio exceeded 50%. In this way, elimination of energy-consuming product recovery process and realization of "energy-saving & waste minimization" industrial production target advocated by the state government, could be potentially expected.
An Optimal Design of Multiple Antenna Positions on Mobile Devices Based on Mutual Coupling Analysis
Peerapong Uthansakul
2011-01-01
Full Text Available The topic of practical implementation of multiple antenna systems for mobile communications has recently gained a lot of attention. Due to the area constraint on a mobile device, the problem of how to design such a system in order to achieve the best benefit is still a huge challenge. In this paper, genetic algorithm (GA is used to find the optimal antenna positions on a mobile device. Two cases of 3×3 and 4×4 MIMO systems are undertaken. The effect of mutual coupling based on Z-parameter is the main factor to determine the MIMO capacity concerning the objective function of GA search. The results confirm the success of the proposed method to design MIMO antenna positions on a mobile device. Moreover, this paper introduces the method to design the antenna positions for the condition of nondeterministic channel. The concern of channel variation has been included in the process of finding optimal MIMO antenna positions. The results suggest that the averaging position from all GA solutions according to all channel conditions provides the most acceptable benefit.
Optimization procedure to control the coupling of vibration modes in flexible space structures
Walsh, Joanne L.
1987-01-01
As spacecraft structural concepts increase in size and flexibility, the vibration frequencies become more closely-spaced. The identification and control of such closely-spaced frequencies present a significant challenge. To validate system identification and control methods prior to actual flight, simpler space structures will be flown. To challenge the above technologies, it will be necessary to design these structures with closely-spaced or coupled vibration modes. Thus, there exists a need to develop a systematic method to design a structure which has closely-spaced vibration frequencies. This paper describes an optimization procedure which is used to design a large flexible structure to have closely-spaced vibration frequencies. The procedure uses a general-purpose finite element analysis program for the vibration and sensitivity analyses and a general-purpose optimization program. Results are presented from two studies. The first study uses a detailed model of a large flexible structure to design a structure with one pair of closely-spaced frequencies. The second study uses a simple equivalent beam model of a large flexible structure to obtain a design with two pairs of closely-spaced frequencies.
Air-cathode structure optimization in separator-coupled microbial fuel cells
Zhang, Xiaoyuan
2011-12-01
Microbial fuel cells (MFC) with 30% wet-proofed air cathodes have previously been optimized to have 4 diffusion layers (DLs) in order to limit oxygen transfer into the anode chamber and optimize performance. Newer MFC designs that allow close electrode spacing have a separator that can also reduce oxygen transfer into the anode chamber, and there are many types of carbon wet-proofed materials available. Additional analysis of conditions that optimize performance is therefore needed for separator-coupled MFCs in terms of the number of DLs and the percent of wet proofing used for the cathode. The number of DLs on a 50% wet-proofed carbon cloth cathode significantly affected MFC performance, with the maximum power density decreasing from 1427 to 855mW/m 2 for 1-4 DLs. A commonly used cathode (30% wet-proofed, 4 DLs) produced a maximum power density (988mW/m 2) that was 31% less than that produced by the 50% wet-proofed cathode (1 DL). It was shown that the cathode performance with different materials and numbers of DLs was directly related to conditions that increased oxygen transfer. The coulombic efficiency (CE) was more affected by the current density than the oxygen transfer coefficient for the cathode. MFCs with the 50% wet-proofed cathode (2 DLs) had a CE of >84% (6.8A/m 2), which was substantially larger than that previously obtained using carbon cloth air-cathodes lacking separators. These results demonstrate that MFCs constructed with separators should have the minimum number of DLs that prevent water leakage and maximize oxygen transfer to the cathode. © 2011 Elsevier B.V.
Pettifor, Audrey; MacPhail, Catherine; Nguyen, Nadia; Rosenberg, Molly; Parker, Lisa; Sibeko, Jabu
2014-04-01
Given the importance of couples to the transmission of HIV, interventions focusing on both members of a partnership can play an important role in its prevention. We adapted and pilot-tested Project Connect, an evidence-based HIV prevention intervention for couples, to determine its acceptability and feasibility among a sample of young urban South African couples. We recruited couples from a clinic in inner-city Johannesburg to take part in the study. Interviewer-administered questionnaires were conducted at baseline and postintervention; an in-depth interview (IDI) was also conducted postintervention. Of 75 couples screened, 15 were eligible and enrolled. An important reason for ineligibility was a recent history of intimate partner violence (IPV). Couples attended, on average, five of the seven sessions. Overall, the intervention was acceptable and showed signs of potential efficacy. Couples reported enjoying Connect and feeling comfortable with its content. Participants also reported learning important communication and problem-solving skills, which resulted in more effective engagement in HIV prevention behaviors. However, the number of sessions and strict eligibility criteria proved challenging to the feasibility of the study. We recommend future couples' interventions have fewer sessions and enroll couples with a history of IPV.
An optimized outlier detection algorithm for jury-based grading of engineering design projects
Thompson, Mary Kathryn; Espensen, Christina; Clemmensen, Line Katrine Harder
2016-01-01
This work characterizes and optimizes an outlier detection algorithm to identify potentially invalid scores produced by jury members while grading engineering design projects. The paper describes the original algorithm and the associated adjudication process in detail. The impact of the various......, but no true optimum seems to exist. The performance of the best optimizations and the original algorithm are similar. Therefore, it should be possible to choose new coefficient values for jury populations in other cultures and contexts logically and empirically without a full optimization as long...
Optimizing Prevention of HIV and Unplanned Pregnancy in Discordant African Couples.
Wall, Kristin M; Kilembe, William; Vwalika, Bellington; Haddad, Lisa B; Khu, Naw Htee; Brill, Ilene; Onwubiko, Udodirim; Chomba, Elwyn; Tichacek, Amanda; Allen, Susan
2017-08-01
Dual method use, which combines condoms with a more effective modern contraceptive to optimize prevention of HIV and unplanned pregnancy, is underutilized in high-risk heterosexual couples. Heterosexual HIV-discordant Zambian couples were enrolled from couples' voluntary HIV counseling and testing services into an open cohort with 3-monthly follow-up (1994-2012). Relative to dual method use, defined as consistent condom use plus modern contraception, we examine predictors of (1) condom-only use (suboptimal pregnancy prevention) or (2) modern contraceptive use with inconsistent condom use (effective pregnancy prevention and suboptimal HIV prevention). Among 3,049 couples, dual method use occurred in 28% of intervals in M+F- and 23% in M-F+, p < 0.01; condom-only use in 56% in M+F- and 61% in M-F+, p < 0.01; and modern contraceptive use with inconsistent condom use in 16% regardless of serostatus. Predictors (p < 0.05) of condom-only use included the man being HIV+ (adjusted hazard ratio, aHR = 1.15); baseline oral contraceptive pill (aHR = 0.76), injectable (aHR = 0.48), or implant (aHR = 0.60) use; woman's age (aHR = 1.04 per 5 years) and lifetime number of sex partners (aHR = 1.01); postpartum periods (aHR = 1.25); and HIV stage of the index partner III/IV versus I (aHR = 1.10). Predictors (p < 0.05) of modern contraceptive use with inconsistent condom use included woman's age (aHR = 0.94 per 5 years) and HIV+ male circumcision (aHR = 1.51), while time-varying implant use was associated with more consistent condom use (aHR = 0.80). Three-quarters of follow-up intervals did not include dual method use. This highlights the need for counseling to reduce unintended pregnancy and HIV transmission and enable safer conception.
Morgan, F. Dale; Sogade, John
2004-12-14
This project was designed as a broad foundational study of spectral induced polarization (SIP) for characterization of contaminated sites. It encompassed laboratory studies of the effects of chemistry on induced polarization, development of 3D forward modeling and inversion codes, and investigations of inductive and capacitive coupling problems. In the laboratory part of the project a physico-chemical model developed in this project was used to invert laboratory IP spectra for the grain size and the effective grain size distribution of the sedimentary rocks as well as the formation factor, porosity, specific surface area, and the apparent fractal dimension. Furthermore, it was established that the IP response changed with the solution chemistry, the concentration of a given solution chemistry, valence of the constituent ions, and ionic radius. In the field part of the project, a 3D complex forward and inverse model was developed. It was used to process data acquired at two frequencies (1/16 Hz and 1/ 4Hz) in a cross-borehole configuration at the A-14 outfall area of the Savannah River Site (SRS) during March 2003 and June 2004. The chosen SRS site was contaminated with Tetrachloroethylene (TCE) and Trichloroethylene (PCE) that were disposed in this area for several decades till the 1980s. The imaginary conductivity produced from the inverted 2003 data correlated very well with the log10 (PCE) concentration derived from point sampling at 1 ft spacing in five ground-truth boreholes drilled after the data acquisition. The equivalent result for the 2004 data revealed that there were significant contaminant movements during the period March 2003 and June 2004, probably related to ground-truth activities and nearby remediation activities. Therefore SIP was successfully used to develop conceptual models of volume distributions of PCE/TCE contamination. In addition, the project developed non-polarizing electrodes that can be deployed in boreholes for years. A total of 28
Optimal Geoid Modelling to determine the Mean Ocean Circulation - Project Overview and early Results
Fecher, Thomas; Knudsen, Per; Bettadpur, Srinivas; Gruber, Thomas; Maximenko, Nikolai; Pie, Nadege; Siegismund, Frank; Stammer, Detlef
2017-04-01
The ESA project GOCE-OGMOC (Optimal Geoid Modelling based on GOCE and GRACE third-party mission data and merging with altimetric sea surface data to optimally determine Ocean Circulation) examines the influence of the satellite missions GRACE and in particular GOCE in ocean modelling applications. The project goal is an improved processing of satellite and ground data for the preparation and combination of gravity and altimetry data on the way to an optimal MDT solution. Explicitly, the two main objectives are (i) to enhance the GRACE error modelling and optimally combine GOCE and GRACE [and optionally terrestrial/altimetric data] and (ii) to integrate the optimal Earth gravity field model with MSS and drifter information to derive a state-of-the art MDT including an error assessment. The main work packages referring to (i) are the characterization of geoid model errors, the identification of GRACE error sources, the revision of GRACE error models, the optimization of weighting schemes for the participating data sets and finally the estimation of an optimally combined gravity field model. In this context, also the leakage of terrestrial data into coastal regions shall be investigated, as leakage is not only a problem for the gravity field model itself, but is also mirrored in a derived MDT solution. Related to (ii) the tasks are the revision of MSS error covariances, the assessment of the mean circulation using drifter data sets and the computation of an optimal geodetic MDT as well as a so called state-of-the-art MDT, which combines the geodetic MDT with drifter mean circulation data. This paper presents an overview over the project results with focus on the geodetic results part.
Fuzzy Optimization of Construction Engineering Project Schedule Based on Critical Chain Management
Jianbing LIU
2013-07-01
Full Text Available Critical chain management was the very important theory innovation in the development of construction project schedule management field in recent years. Compared with the traditional methods of construction project schedule management, the methods of critical chain management considered resource constraints into construction project schedule management, the construction project cycle was shortened and the efficiency was enhanced by using the dynamic thinking and circulation pattern to manage whole project. In view of the progress of critical chain management of the article, fuzzy theory was used to calculate and optimize the buffer zone sizes with the determination of the buffer size of the existing resources in certain critical chain management so as to shorten the cycle..
吕渭济; 崔巍
2001-01-01
In this paper, two kinds of models are presented and optimized for project investment risk income on the basis of probability X distribution. One kind of model being proved has only a maximal value and another kind being proved has no extreme values.
Diehl, M; Nagel, F
2003-01-01
The sensitivity of optimal integrated observables to electroweak triple gauge couplings is investigated for the process e sup - e sup +->W sup - W sup +->4 fermions at future linear colliders. By a suitable reparameterisation of the couplings we achieve that all 28 coupling parameters have uncorrelated statistical errors and are naturally normalised for this process. Discrete symmetry properties simplify the analysis and allow checks on the stability of numerical results. We investigate the sensitivity to the couplings of the normalised event distribution and the additional constraints that can be obtained from the total rate. Particular emphasis is put on the gain in sensitivity one can achieve with longitudinal beam polarisation. We also point out questions that may best be settled with transversely polarised beams. In particular we find that with purely longitudinal polarisation one linear combination of coupling parameters is hardly measurable by means of the normalised event distribution. (orig.)
Bauer, Fabian; Römer, Ulrich, E-mail: ulrich.roemer@kit.edu; Fidlin, Alexander; Seemann, Wolfgang [Institute of Engineering Mechanics, Karlsruhe Institute of Technology (Germany)
2016-11-15
This paper presents a method to optimize the energy efficiency of walking bipedal robots by more than 80 % in a speed range from 0.3 to 2.3 m/s using elastic couplings—mechanical springs with movement speed independent parameters. The considered planar robot consists of a trunk, two two-segmented legs, two actuators in the hip joints, two actuators in the knee joints and an elastic coupling between the shanks. It is modeled as underactuated system to make use of its natural dynamics and feedback controlled via input–output linearization. A numerical optimization of the joint angle trajectories as well as the elastic couplings is performed to minimize the average energy expenditure over the whole speed range. The elastic couplings increase the swing leg motion’s natural frequency thus making smaller steps more efficient which reduce the impact loss at the touchdown of the swing leg. The process of energy turnover is investigated in detail for the robot with and without elastic coupling between the shanks. Furthermore, the influences of the elastic couplings’ topology and of joint friction are analyzed. It is shown that the optimization of the robot’s motion and elastic coupling towards energy efficiency leads to a slightly slower convergence rate of the controller, yet no loss of stability, but a lower sensitivity with respect to disturbances. The optimal elastic coupling discovered via numerical optimization is a linear torsion spring with transmissions between the shanks. A design proposal for this elastic coupling—which does not affect the robot’s trunk and parallel shank motion and can be used to enhance an existing robot—is given for planar as well as spatial robots.
Pettifor, Audrey; MacPhail, Catherine; Nguyen, Nadia; Rosenberg, Molly; Parker, Lisa; Sibeko, Jabu
2013-01-01
Given the importance of couples to the transmission of HIV, interventions focusing on both members of a partnership can play an important role in its prevention. We adapted and pilot tested Project Connect, an evidence-based HIV prevention intervention for couples, to determine its acceptability and feasibility among a sample of young urban South African couples. We recruited couples from a clinic in inner-city Johannesburg to take part in the study. Interviewer-administered questionnaires were conducted at baseline and post-intervention; an in-depth interview was also conducted post-intervention. Of 75 couples screened, 15 were eligible and enrolled. An important reason for ineligibility was a recent history of intimate partner violence (IPV). Couples attended, on average, five of the seven sessions. Overall, the intervention was acceptable and showed signs of potential efficacy. Couples reported enjoying Connect and feeling comfortable with its content. Participants also reported learning important communication and problem-solving skills, which resulted in more effective engagement in HIV prevention behaviors. However, the number of sessions and strict eligibility criteria proved challenging to the feasibility of the study. We recommend future couples’ interventions have fewer sessions and enroll couples with a history of IPV. PMID:24116954
On the similarities between micro/nano lithography and topology optimization projection methods
Jansen, Miche; Lazarov, Boyan Stefanov; Schevenels, Mattias;
2013-01-01
The aim of this paper is to incorporate a model for micro/nano lithography production processes in topology optimization. The production process turns out to provide a physical analogy for projection filters in topology optimization. Blueprints supplied by the designers cannot be directly used...... projection filter can be used to account for uncertainties due to lithographic production processes which results in manufacturable blueprint designs and eliminates the need for subsequent corrections....... as inputs to lithographic processes due to the proximity effect which causes rounding of sharp corners and geometric interaction of closely spaced design elements. Therefore, topology optimization is applied as a tool for proximity effect correction. Furthermore, it is demonstrated that the robust...
Optimization of Multi-Project Multi-Site Location Based on MOPSOs
ZHANG Yong; GONG Dun-wei; ZHOU Yong
2006-01-01
Multi-project multi-site location problems are multi-objective combinational optimization ones with discrete variables which are hard to solve. To do so, the case of particle swarm optimization is considered due to its useful characteristics such as easy implantation, simple parameter settings and fast convergence. First these problems are transformed into ones with continuous variables by defining an equivalent probability matrix in this paper, then multi-objective particle swarm optimization based on the minimal particle angle is used to solve them. Methods such as continuation of discrete variables, update of particles for matrix variables, normalization of particle position and evaluation of particle fitness are presented. Finally the efficiency of the proposed method is validated by comparing it with other methods on an eight-project-ten-site location problem.
Vorontsov, Mikhail; Weyrauch, Thomas; Lachinova, Svetlana; Gatz, Micah; Carhart, Gary
2012-07-15
Maximization of a projected laser beam's power density at a remotely located extended object (speckle target) can be achieved by using an adaptive optics (AO) technique based on sensing and optimization of the target-return speckle field's statistical characteristics, referred to here as speckle metrics (SM). SM AO was demonstrated in a target-in-the-loop coherent beam combining experiment using a bistatic laser beam projection system composed of a coherent fiber-array transmitter and a power-in-the-bucket receiver. SM sensing utilized a 50 MHz rate dithering of the projected beam that provided a stair-mode approximation of the outgoing combined beam's wavefront tip and tilt with subaperture piston phases. Fiber-integrated phase shifters were used for both the dithering and SM optimization with stochastic parallel gradient descent control.
Cheemalapati, Surya; Ladanov, Mikhail; Winskas, John; Pyayt, Anna
2014-09-01
In this paper, we demonstrate the optimization of a capacitively coupled plasma etching for the fabrication of a polysilicon waveguide with smooth sidewalls and low optical loss. A detailed experimental study on the influences of RF plasma power and chamber pressure on the roughness of the sidewalls of waveguides was conducted and waveguides were characterized using a scanning electron microscope. It was demonstrated that optimal combination of pressure (30 mTorr) and power (150 W) resulted in the smoothest sidewalls. The optical losses of the optimized waveguide were 4.1±0.6 dB/cm.
Ke, Quan; Luo, Weijie; Yan, Guozheng; Yang, Kai
2016-04-01
A wireless power transfer system based on the weakly inductive coupling makes it possible to provide the endoscope microrobot (EMR) with infinite power. To facilitate the patients' inspection with the EMR system, the diameter of the transmitting coil is enlarged to 69 cm. Due to the large transmitting range, a high quality factor of the Litz-wire transmitting coil is a necessity to ensure the intensity of magnetic field generated efficiently. Thus, this paper builds an analytical model of the transmitting coil, and then, optimizes the parameters of the coil by enlarging the quality factor. The lumped model of the transmitting coil includes three parameters: ac resistance, self-inductance, and stray capacitance. Based on the exact two-dimension solution, the accurate analytical expression of ac resistance is derived. Several transmitting coils of different specifications are utilized to verify this analytical expression, being in good agreements with the measured results except the coils with a large number of strands. Then, the quality factor of transmitting coils can be well predicted with the available analytical expressions of self- inductance and stray capacitance. Owing to the exact estimation of quality factor, the appropriate coil turns of the transmitting coil is set to 18-40 within the restrictions of transmitting circuit and human tissue issues. To supply enough energy for the next generation of the EMR equipped with a Ø9.5×10.1 mm receiving coil, the coil turns of the transmitting coil is optimally set to 28, which can transfer a maximum power of 750 mW with the remarkable delivering efficiency of 3.55%.
Nhat-Duc Hoang
2015-01-01
Full Text Available In construction management, the task of planning project schedules with consideration of labor utilization is very crucial. However, the commonly used critical path method (CPM does not inherently take into account this issue. Consequently, the labor utilization of the project schedule derived from the CPM method often has substantial low ebbs and high peaks. This research proposes a model to obtain project schedule with the least fluctuation in labor demand while still satisfying the project deadline and maintain the project cost. The Differential Evolution (DE, a fast and efficient metaheuristic, is employed to search for the most desirable solution of project execution among numerous combinations of activities’ crew sizes and start times. Furthermore, seven DE’s mutation strategies have also been employed for solving the optimization at hand. Experiment results point out that the Target-to-Best 1 and a new hybrid mutation strategy can attain the best solution of project schedule with the least fluctuation in labor demand. Accordingly, the proposed framework can be an effective tool to assist decision-makers in the project planning phase.
An optimized outlier detection algorithm for jury-based grading of engineering design projects
Thompson, Mary Kathryn; Espensen, Christina; Clemmensen, Line Katrine Harder
2016-01-01
This work characterizes and optimizes an outlier detection algorithm to identify potentially invalid scores produced by jury members while grading engineering design projects. The paper describes the original algorithm and the associated adjudication process in detail. The impact of the various...... conditions in the algorithm on the false positive and false negative rates is explored. Aresponse surface design is performed to optimize the algorithm using a data set from Fall 2010. Finally, the results are tested against a data set from Fall 2011. It is shown that all elements of the original algorithm......, but no true optimum seems to exist. The performance of the best optimizations and the original algorithm are similar. Therefore, it should be possible to choose new coefficient values for jury populations in other cultures and contexts logically and empirically without a full optimization as long...
Welsch, Bastian; Rühaak, Wolfram; Schulte, Daniel O.; Formhals, Julian; Bär, Kristian; Sass, Ingo
2017-04-01
Large-scale borehole thermal energy storage (BTES) is a promising technology in the development of sustainable, renewable and low-emission district heating concepts. Such systems consist of several components and assemblies like the borehole heat exchangers (BHE), other heat sources (e.g. solarthermics, combined heat and power plants, peak load boilers, heat pumps), distribution networks and heating installations. The complexity of these systems necessitates numerical simulations in the design and planning phase. Generally, the subsurface components are simulated separately from the above ground components of the district heating system. However, as fluid and heat are exchanged, the subsystems interact with each other and thereby mutually affect their performances. For a proper design of the overall system, it is therefore imperative to take into account the interdependencies of the subsystems. Based on a TCP/IP communication we have developed an interface for the coupling of a simulation package for heating installations with a finite element software for the modeling of the heat flow in the subsurface and the underground installations. This allows for a co-simulation of all system components, whereby the interaction of the different subsystems is considered. Furthermore, the concept allows for a mathematical optimization of the components and the operational parameters. Consequently, a finer adjustment of the system can be ensured and a more precise prognosis of the system's performance can be realized.
Technical note: optimization of lactose quantification based on coupled enzymatic reactions.
Condezo-Hoyos, Luis; Mohanty, Indira P; Noratto, Giuliana D
2014-01-01
A colorimetric microplate-adapted lactose assay was developed to quantify lactose in dairy products. The assay was based on the coupled enzymatic reaction of β-galactosidase-glucose oxidase-horseradish peroxidase using Amplex red as detection probe. The assay showed good linearity in the range of 0.1 to 0.5mmol of lactose/L, with a limit of detection of 0.0433mmol/L and a limit of quantification of 0.1313mmol/L. The lactose assay at optimized conditions (5 U of β-galactosidase/mL, 5 U of glucose oxidase/mL, 1 U of horseradish peroxidase/mL, and 100μmol of Amplex red/L for 1h at 37°C in the dark) showed good correlation with a commercial lactose enzymatic kit with intraassay variation below 10% and interassay variations below 7.6%. The developed lactose microplate assay can be adopted as routine analysis for lactose determination in dairy products due to its relatively low cost compared with a commercial kit, relatively short reaction time, and high sensitivity and reproducibility.
Optimization study of coupled hydrogen moderator with extended pre-moderator
Kai, Tetsuya; Teshigawara, Makoto; Watanabe, Noboru; Harada, Masahide; Sakata, Hideaki; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
2001-03-01
We performed an optimization study of an extended pre-moderator (PM) for a coupled supercritical hydrogen (H{sub 2}) moderator in a lead reflected system. We found that the extended PM could eliminate a backside PM which had been believed to be indispensable from a neutronic point of view. This means that neutron beams can be extracted from both viewed surfaces of one moderator, so that two H{sub 2} moderators can be replaced by one H{sub 2} without sacrificing neutron intensity. In this paper, we compared neutronic performances of these two moderator systems; one-moderator system and two-moderator systems. Neutron beams are extracted from both viewed surfaces in the former, while in the latter two H{sub 2} moderators having one viewed surface, respectively, share the PM in the backside. We concluded the one-moderator system exhibits a better neutronic performance with a lower heat deposition in H{sub 2} comparing to the two-moderator systems. We briefly compared the neutronic characteristics between the lead and beryllium reflected system. It was found that the lead reflected system could provide a higher pulse peak with a narrower pulse width and a faster-decay time than the beryllium one, although the time-integrated intensity is lower than the latter. (author)
Brijesh Prasad
2011-08-01
Full Text Available Batch experiments were conducted to investigate the fermentative hydrogen production by coupled system of Halobacterium salinarium and E. coli. Increase in the light intensity from 6000 lux to 12000 lux and changing the inoculums level of E coli resulted in 10 fold increase in the rate of hydrogen production using the coupled system. Statistical based design of experiments was applied to optimize the rate of hydrogen production using milk plasma,popularly known as cheese whey, a dairy industry byproduct. An optimal rate of hydrogen production of 56.7 ml/l h was achieved with 14.42 % (by volume of milk plasma and an initial pH of 6.6. The investigations provided information on achieving higher yields with milk plasma as substrate, its optimal concentration, and importance of media pH for producing higher rate of hydrogen.
Campozana, Fernando P.; Almeida, Renato L. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Madeira, Marcelo G.; Sousa, Sergio H.G. de; Spinola, Marcio [Halliburton Servicos Ltda., Rio de Janeiro, RJ (Brazil)
2008-07-01
To design, modify, and expand surface facilities is a multidisciplinary task which involves substantial financial resources. It can take months or years to complete, depending on the size and level of detail of the project. Nowadays, the use of Next Generation Reservoir Simulators (NGRS) is the most sophisticated and reliable way of obtaining field performance evaluation since they can couple surface and subsurface equations, thus eliminating the need of lengthy multiphase flow tables. Furthermore, coupling a NGRS with an optimizer is the best way to accomplish a large number of simulation runs on the search for optimized solutions when facilities are being modified and/or expanded. The suggested workflow is applied to a synthetic field which reproduces typical Brazilian offshore deep water scenarios. Hundreds of coupled simulation runs were performed and the results show that it is possible to find optimal diameters for the production lines as well as the ideal location for the production / injection platform. (author)
Liu, Long; Sun, Jun; Xu, Wenbo; Du, Guocheng; Chen, Jian
2009-01-01
Hyaluronic acid (HA) is a natural biopolymer with unique physiochemical and biological properties and finds a wide range of applications in biomedical and cosmetic fields. It is important to increase HA production to meet the increasing HA market demand. This work is aimed to model and optimize the amino acids addition to enhance HA production of Streptococcus zooepidemicus with radial basis function (RBF) neural network coupling quantum-behaved particle swarm optimization (QPSO) algorithm. In the RBF-QPSO approach, RBF neural network is used as a bioprocess modeling tool and QPSO algorithm is applied to conduct the optimization with the established RBF neural network black model as the objective function. The predicted maximum HA yield was 6.92 g/L under the following conditions: arginine 0.062 g/L, cysteine 0.036 g/L, and lysine 0.043 g/L. The optimal amino acids addition allowed HA yield increased from 5.0 g/L of the control to 6.7 g/L in the validation experiments. Moreover, the modeling and optimization capacity of the RBF-QPSO approach was compared with that of response surface methodology (RSM). It was indicated that the RBF-QPSO approach gave a slightly better modeling and optimization result compared with RSM. The developed RBF-QPSO approach in this work may be helpful for the modeling and optimization of the other multivariable, nonlinear, time-variant bioprocesses.
Farshad Faezy Razi
2014-01-01
Full Text Available The problem of selection and the best option are the main subject of operation research science in decision-making theory. Selection is a process that scrutinizes and investigates several quantitative and qualitative, and most often incompatible, factors. One of the most fundamental management issues in multicriteria selection literature is the multicriteria adoption of the projects portfolio. In such decision-making condition, manager is seeking for the best combination to build up a portfolio among the existing projects. In the present paper, KOHONEN algorithm was first employed to build up a portfolio of the projects. Next, each portfolio was evaluated using grey relational analysis (GRA and then scheduled risk of the project was predicted using Mamdani fuzzy inference method. Finally, the multiobjective biogeography-based optimization algorithm was utilized for drawing risk and rank Pareto analysis. A case study is used concurrently to show the efficiency of the proposed model.
Optimal Duration of Submersible Pump Equipped Deep Water Borehole Project in Ikwuano, Nigeria
Nwankwojike, B. Nduka
2014-12-01
Full Text Available Optimal duration for constructing a submersible pump equipped deep water borehole in Ikwuano and optimal durations of distinct jobs in this project were determined to aid effective planning and implementation of borehole projects in this area. The investigation was conducted and analyzed using network modeling procedure. Results revealed 13days as the optimal duration of the borehole project when construction of overhead water distribution tank stantion constitutes part of the contract and 12days when the overhead structure is not involved. The optimal duration in hours for the distinct jobs involved in this borehole construction include 25.92 for site preparation/mobilization of geophysical survey team, 36 for geophysical analysis/selection of the best water yielding point in the site, 72 for mobilizing labour and materials to the selected site, 168 for constructing overhead water distribution tank stantion, 3.12 for placement of overhead tank(s on its stantion/installation of its water conveying pipes/accessories, 4.56 for casing/gravel packing/flushing materials preparation, 19.44 for well drilling, 1.92 for casing, 1.92 for gravel packing, 1.2 for flushing, 25.92 for water collection/analysis, 1.2 for water treatment, 13.44 for pumping test, 25.92 for platforming, 77.04 for pump installation/integration of water conveying systems, 4.8 for test running and 0.96 for training end users/project commission. Thus, a guide for effective planning to ensure adequate and timely implementation of deep borehole water supply projects in Ikwuano is set.
2013-07-18
Element Coupled Optimization and NDE S. Ratnajeevan H. Hoole1, Victor U. Karthik1, Sivamayam Sivasuthan1, Arunasalam Rahunanthan2, Ravi S...Department of Mathematics and Statistics, University of Toledo , Toledo , OH 43606-3390, USA. 3. The US Army Tank Automotive Research, Development and...PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Paramsothy Jayakumar; Ravi Thyagarajan; Arunasalam Rahunanthan; Sivamayam Sivasuthan; Victor Karthik 5d
Future Evolution of Marine Heat Waves in the Mediterranean: Coupled Regional Climate Projections
Darmaraki, Sofia; Somot, Samuel; Sevault, Florence; Nabat, Pierre; Cavicchia, Leone; Djurdjevic, Vladimir; Cabos, William; Sein, Dmitry
2017-04-01
FUTURE EVOLUTION OF MARINE HEAT WAVES IN THE MEDITERRANEAN : COUPLED REGIONAL CLIMATE PROJECTIONS The Mediterranean area is identified as a « Hot Spot » region, vulnerable to future climate change with potentially strong impacts over the sea. By 2100, climate models predict increased warming over the sea surface, with possible implications on the Mediterranean thermohaline and surface circulation,associated also with severe impacts on the ecosystems (e.g. fish habitat loss, species extinction and migration, invasive species). However, a robust assesment of the future evolution of the extreme marine temperatures remains still an open issue of primary importance, under the anthropogenic pressure. In this context, we study here the probability and characteristics of marine heat wave (MHW) occurrence in the Mediterranean Sea in future climate projections. To this end, we use an ensemble of fully coupled regional climate system models (RCSM) from the Med- CORDEX initiative. This multi-model approach includes a high-resolution representation of the atmospheric, land and ocean component, with a free air-sea interface.Specifically, dedicated simulations for the 20th and the 21st century are carried out with respect to the different IPCC-AR5 socioeconomic scenarios (1950-2100, RCP8.5, RCP4.5, RCP2.6). Model evaluation for the historical period is performed using satellite and in situ data. Then, the variety of factors that can cause the MHW (e.g. direct radiative forcing, ocean advection, stratification change) are examined to disentangle the dominant driving force. Finally, the spatial variability and temporal evolution of MHW are analyzed on an annual basis, along with additional integrated indicators, useful for marine ecosystems.
Low Speed Motion Optimization of Space Manipulator Based on Gradient Projection Method
Peng Junjie
2015-01-01
Full Text Available Low-speed crawling phenomenon may occur when space manipulators run at a low speed, which may bring big problem for manipulation work. A kind of low-speed optimization algorithm based on gradient projection method is pro-posed in this paper. The designing of continuous balanced proportional factor can effectively reduce the quantitative differences between the homogeneous solution and the special solution, avoiding the joint velocities oscillations. The low-speed crawling problem can be effectively improved by appropriate increase of joint velocities. And the effectiveness and correctness of the optimization algorithm are confirmed by the simulation.
Analyzing the Quantum Zeno and anti-Zeno effects using optimal projective measurements.
Aftab, Muhammad Junaid; Chaudhry, Adam Zaman
2017-09-18
Measurements in quantum mechanics can not only effectively freeze the quantum system (the quantum Zeno effect) but also accelerate the time evolution of the system (the quantum anti-Zeno effect). In studies of these effects, a quantum state is prepared repeatedly by projecting the quantum state onto the initial state. In this paper, we repeatedly prepare the initial quantum state in a different manner. Instead of only performing projective measurements, we allow unitary operations to be performed, on a very short time-scale, after each measurement. We can then repeatedly prepare the initial state by performing some projective measurement and then, after each measurement, we perform a suitable unitary operation to end up with the same initial state as before. Our objective is to find the projective measurements that minimize the effective decay rate of the quantum state. We find such optimal measurements and the corresponding decay rates for a variety of system-environment models such as the pure dephasing model and the spin-boson model. We find that there can be considerable differences between this optimized effective decay rate and the usual decay rate obtained by repeatedly projecting onto the initial state. In particular, the Zeno and anti-Zeno regimes can be considerably modified.
Strongly Coupled Fluid-Body Dynamics in the Immersed Boundary Projection Method
Wang, Chengjie; Eldredge, Jeff D.
2014-11-01
A computational algorithm is developed to simulate dynamically coupled interaction between fluid and rigid bodies. The basic computational framework is built upon a multi-domain immersed boundary method library, whirl, developed in previous work. In this library, the Navier-Stokes equations for incompressible flow are solved on a uniform Cartesian grid by the vorticity-based immersed boundary projection method of Colonius and Taira. A solver for the dynamics of rigid-body systems is also included. The fluid and rigid-body solvers are strongly coupled with an iterative approach based on the block Gauss-Seidel method. Interfacial force, with its intimate connection with the Lagrange multipliers used in the fluid solver, is used as the primary iteration variable. Relaxation, developed from a stability analysis of the iterative scheme, is used to achieve convergence in only 2-4 iterations per time step. Several two- and three-dimensional numerical tests are conducted to validate and demonstrate the method, including flapping of flexible wings, self-excited oscillations of a system of linked plates and three-dimensional propulsion of flexible fluked tail. This work has been supported by AFOSR, under Award FA9550-11-1-0098.
Isabel, J. A. de
2009-07-01
In shallow geothermal energy applications, the filling material through the borehole is considered as a main feature in every geothermal project. The use of an adequate filling material decrease the necessary number of linear meters for a correct geothermical exchange, dropping the play back period of the installation as well. The use of this kind of material in the field of single-family houses means a direct benefit of the owner, as the installation will increase its seasonal performance factor, droping the electrical consumption. Likewise in big geothermal project the optimization of the installation can only be achieved with the use of a proper geothermal filling material. (Author) 4 refs.
Fernando Henrique Lermen
2016-09-01
Full Text Available The PERT/CPM is a technique widely used in both the scheduling and in the project feasibility in terms of cost control and time. In order to optimize time and costs involved in production, the work presented here aims to apply the PERT/CPM technique in the production project of the Horizontal Laminator, a machine used to cut polyurethane foam blocks in the mattresses industries. For the application of PERT/CPM technique in the project of Horizontal Laminator production were identified the activities that compose the project, the dependence between them, the normal and accelerated durations and the normal and accelerated costs. In this study, deterministic estimates for the duration of the activities were considered. The results show that the project can be completed in 520 hours at a total cost of R$7,042.50, when all activities are performed in their normal durations. When all the activities that compose the critical path are accelerated, the project can be completed in 333.3 hours at a total cost of R$9,263.01. If the activities slacks have been exploited, it can obtain a final total cost of R$6,157.8, without changing the new duration of the project. It is noteworthy that the final total cost of the project if the slacks are used, will be lower than the initial cost. Regarding the initial cost of the project, after the application of the PERT/CPM technique, it presents a decrease of 12.56% of the total project cost.
Application of Particle Swarm Optimization to Formative E-Assessment in Project Management
Maria-Iuliana DASCALU
2011-01-01
Full Text Available The current paper describes the application of Particle Swarm Optimization algorithm to the formative e-assessment problem in project management. The proposed approach resolves the issue of personalization, by taking into account, when selecting the item tests in an e-assessment, the following elements: the ability level of the user, the targeted difficulty of the test and the learning objectives, represented by project management concepts which have to be checked. The e-assessment tool in which the Particle Swarm Optimization algorithm is integrated is also presented. Experimental results and comparison with other algorithms used in item tests selection prove the suitability of the proposed approach to the formative e-assessment domain. The study is presented in the framework of other evolutionary and genetic algorithms applied in e-education.
Methods of determining the optimal project of reconstruction of The Petrovsky Dock in Kronstadt
Romanovich Marina
2016-01-01
Full Text Available Today in Russia there are many historical monuments, which are in a derelict and not the operational state. So, this is actual question about their reconstruction with preservation of historical significance, with current technology, and innovation. One of these abandoned objects is The Petrovsky Dock in Kronstadt. Priority idea of its reconstruction it is museum. The Russian and foreign experience in development of the modern sea museums is analysed. In article the existing options of reconstruction of Dock are considered. The method of calculation of total optimality project coefficient of reconstruction is offered. Survey of experts showing what functions are most interesting to the museum is conducted. As a result, we determine the optimal reconstruction project of Dock with unique functionality.
Conformal BaTiO3 Films with High Piezoelectric Coupling through an Optimized Hydrothermal Synthesis.
Zhou, Zhi; Bowland, Christopher C; Patterson, Brendan A; Malakooti, Mohammad H; Sodano, Henry A
2016-08-24
Two-dimensional (2D) ferroelectric films have vast applications due to their dielectric, ferroelectric, and piezoelectric properties that meet the requirements of sensors, nonvolatile ferroelectric random access memory (NVFeRAM) devices, and micro-electromechanical systems (MEMS). However, the small surface area of these 2D ferroelectric films has limited their ability to achieve higher memory storage density in NVFeRAM devices and more sensitive sensors and transducer. Thus, conformally deposited ferroelectric films have been actively studied for these applications in order to create three-dimensional (3D) structures, which lead to a larger surface area. Most of the current methods developed for the conformal deposition of ferroelectric films, such as metal-organic chemical vapor deposition (MOCVD) and plasma-enhanced vapor deposition (PECVD), are limited by high temperatures and unstable and toxic organic precursors. In this paper, an innovative fabrication method for barium titanate (BaTiO3) textured films with 3D architectures is introduced to alleviate these issues. This fabrication method is based on converting conformally grown rutile TiO2 nanowire arrays into BaTiO3 textured films using a simple two-step hydrothermal process which allows for thickness-controlled growth of conformal films on patterned silicon wafers coated with fluorine-doped tin oxide (FTO). Moreover, the processing parameters have been optimized to achieve a high piezoelectric coupling coefficient of 100 pm/V. This high piezoelectric response along with high relative dielectric constant (εr = 1600) of the conformally grown textured BaTiO3 films demonstrates their potential application in sensors, NVFeRAM, and MEMS.
Hyland, D. C.
1985-01-01
The underlying philosophy and motivation of the optimal projection/maximum entropy (OP/ME) stochastic modelling and reduced order control design method for high order systems with parameter uncertainties are discussed. The OP/ME design equations for reduced-order dynamic compensation including the effect of parameter uncertainties are reviewed and the application of the methodology to several large space structure (LSS) problems of representative complexity is illustrated.
Shin, Sun-Hee; Kim, Ok-Yeon; Kim, Dongmin; Lee, Myong-In
2017-07-01
Using 32 CMIP5 (Coupled Model Intercomparison Project Phase 5) models, this study examines the veracity in the simulation of cloud amount and their radiative effects (CREs) in the historical run driven by observed external radiative forcing for 1850-2005, and their future changes in the RCP (Representative Concentration Pathway) 4.5 scenario runs for 2006-2100. Validation metrics for the historical run are designed to examine the accuracy in the representation of spatial patterns for climatological mean, and annual and interannual variations of clouds and CREs. The models show large spread in the simulation of cloud amounts, specifically in the low cloud amount. The observed relationship between cloud amount and the controlling large-scale environment are also reproduced diversely by various models. Based on the validation metrics, four models—ACCESS1.0, ACCESS1.3, HadGEM2-CC, and HadGEM2-ES—are selected as best models, and the average of the four models performs more skillfully than the multimodel ensemble average. All models project global-mean SST warming at the increase of the greenhouse gases, but the magnitude varies across the simulations between 1 and 2 K, which is largely attributable to the difference in the change of cloud amount and distribution. The models that simulate more SST warming show a greater increase in the net CRE due to reduced low cloud and increased incoming shortwave radiation, particularly over the regions of marine boundary layer in the subtropics. Selected best-performing models project a significant reduction in global-mean cloud amount of about -0.99% K-1 and net radiative warming of 0.46 W m-2 K-1, suggesting a role of positive feedback to global warming.
Yoo, Do Guen; Lee, Ho Min; Sadollah, Ali; Kim, Joong Hoon
2015-01-01
Water supply systems are mainly classified into branched and looped network systems. The main difference between these two systems is that, in a branched network system, the flow within each pipe is a known value, whereas in a looped network system, the flow in each pipe is considered an unknown value. Therefore, an analysis of a looped network system is a more complex task. This study aims to develop a technique for estimating the optimal pipe diameter for a looped agricultural irrigation water supply system using a harmony search algorithm, which is an optimization technique. This study mainly serves two purposes. The first is to develop an algorithm and a program for estimating a cost-effective pipe diameter for agricultural irrigation water supply systems using optimization techniques. The second is to validate the developed program by applying the proposed optimized cost-effective pipe diameter to an actual study region (Saemangeum project area, zone 6). The results suggest that the optimal design program, which applies an optimization theory and enhances user convenience, can be effectively applied for the real systems of a looped agricultural irrigation water supply.
Do Guen Yoo
2015-01-01
Full Text Available Water supply systems are mainly classified into branched and looped network systems. The main difference between these two systems is that, in a branched network system, the flow within each pipe is a known value, whereas in a looped network system, the flow in each pipe is considered an unknown value. Therefore, an analysis of a looped network system is a more complex task. This study aims to develop a technique for estimating the optimal pipe diameter for a looped agricultural irrigation water supply system using a harmony search algorithm, which is an optimization technique. This study mainly serves two purposes. The first is to develop an algorithm and a program for estimating a cost-effective pipe diameter for agricultural irrigation water supply systems using optimization techniques. The second is to validate the developed program by applying the proposed optimized cost-effective pipe diameter to an actual study region (Saemangeum project area, zone 6. The results suggest that the optimal design program, which applies an optimization theory and enhances user convenience, can be effectively applied for the real systems of a looped agricultural irrigation water supply.
Rimjaem, S., E-mail: r.sakhorn@gmail.com [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Stephan, F.; Krasilnikov, M. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Ackermann, W. [Technische Universtaet Darmstadt, Schossgartenstrasse 8, 64289 Darmstadt (Germany); Asova, G.; Baehr, J. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Gjonaj, E. [Technische Universtaet Darmstadt, Schossgartenstrasse 8, 64289 Darmstadt (Germany); Grabosch, H.J.; Hakobyan, L.; Haenel, M.; Ivanisenko, Y.; Khojoyan, M.; Klemz, G. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Lederer, S. [Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg (Germany); Mahgoub, M. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Michelato, P.; Monaco, L. [Istituto Nazionale di Fisica Nucleare, Sezione di Milano - LASA, Via F.lli Cervi 201, 20090 Segrate Milano (Italy); Nozdrin, M.; O' Shea, B.; Otevrel, M. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); and others
2012-04-11
High brightness electron sources for linac based short-wavelength free-electron lasers are developed and optimized for small transverse projected emittance at the photo-injector test facility at DESY, location Zeuthen (PITZ). A major part of the measurement program at PITZ is dedicated to transverse phase space optimization in order to fulfill the requirements of the European X-ray free-electron laser (European XFEL). A laser-driven RF-gun, treated with a dry-ice sublimation-impulse cleaning technique, a new photocathode laser system allowing short rise and fall times of the flat-top temporal distribution as well as several new diagnostic components have been installed at PITZ in 2008. The electrons generated via the photo-effect at a cesium telluride (Cs{sub 2}Te) cathode are accelerated by a 1.6 cell L-band RF-gun cavity with a maximum accelerating gradient at the cathode of about 60 MV/m. The transverse projected emittance is measured using a single slit scan technique. In the 2008-2009 run period, a detailed characterization of the projected transverse emittance was performed at different operating conditions. Optimizations and measurement results as well as simulation predictions of the transverse projected emittance for bunch charges of 1, 0.5, 0.25 and 0.1 nC are presented and discussed in this paper. The geometric mean of the normalized projected rms emittance in both transverse directions for an electron bunch charge of 1 nC was measured to be 0.89{+-}0.01 mm mrad for a 100% rms phase-space distribution.
Yang, Jian; Cong, Weijian; Chen, Yang; Fan, Jingfan; Liu, Yue; Wang, Yongtian
2014-02-21
The clinical value of the 3D reconstruction of a coronary artery is important for the diagnosis and intervention of cardiovascular diseases. This work proposes a method based on a deformable model for reconstructing coronary arteries from two monoplane angiographic images acquired from different angles. First, an external force back-projective composition model is developed to determine the external force, for which the force distributions in different views are back-projected to the 3D space and composited in the same coordinate system based on the perspective projection principle of x-ray imaging. The elasticity and bending forces are composited as an internal force to maintain the smoothness of the deformable curve. Second, the deformable curve evolves rapidly toward the true vascular centerlines in 3D space and angiographic images under the combination of internal and external forces. Third, densely matched correspondence among vessel centerlines is constructed using a curve alignment method. The bundle adjustment method is then utilized for the global optimization of the projection parameters and the 3D structures. The proposed method is validated on phantom data and routine angiographic images with consideration for space and re-projection image errors. Experimental results demonstrate the effectiveness and robustness of the proposed method for the reconstruction of coronary arteries from two monoplane angiographic images. The proposed method can achieve a mean space error of 0.564 mm and a mean re-projection error of 0.349 mm.
2009-01-01
The paper is concerned with a stochastic optimal control problem in which the controlled system is described by a fully coupled nonlinear forward-backward stochastic differential equation driven by a Brownian motion.It is required that all admissible control processes are adapted to a given subfiltration of the filtration generated by the underlying Brownian motion.For this type of partial information control,one sufficient(a verification theorem) and one necessary conditions of optimality are proved.The control domain need to be convex and the forward diffusion coefficient of the system can contain the control variable.
MENG QingXin
2009-01-01
The paper is concerned with a stochastic optimal control problem in which the controlled system is described by a fully coupled nonlinear forward-backward stochastic differential equation driven by a Brownian motion. It is required that all admissible control processes are adapted to a given subfiltration of the filtration generated by the underlying Brownian motion. For this type of partial information control, one sufficient (a verification theorem) and one necessary conditions of optimality are proved. The control domain need to be convex and the forward diffusion coefficient of the system can contain the control variable.
MATHEMATICAL MODEL OF OPTIMAL PROJECT PORTFOLIO FORMING BASED ON RANDOM FACTORS
I. A. Korkhina
2014-03-01
Full Text Available Purpose. To identify the ways of perspective development for railway transport one should solve the problem of forming the investment project portfolio. Thus, it is necessary to deal with uncertainty in the input data (prices of services, materials, energy products. To take into account this uncertainty it is proposed to use the developed model of stochastic programming. Methodology. For accounting of uncertain data the probabilistic limits on the quantities of resources, which are used in the project portfolio are imposed. As the objective function it is proposed to maximize the threshold, which with a given probability may exceed the planning interval of the net income. Findings. Stochastic programming model with line-by-line probabilistic constraints was obtained. Coefficients of this model are normally distributed random variables. Ratios, which allow calculating mathematical expectations and covariance matrices of these coefficients, were concluded. Originality. Known methods of forming the optimal project portfolio are based on the fact that all inputs are known exactly. On the basis of this consideration, the authors of works on the creating an optimal project portfolio have come to a scheme of deterministic mathematical programming. In this article we propose to take into account the uncertainty in the input data, which will increase the reliability of the portfolio effectiveness estimation through the use of stochastic mathematical programming scheme. Practical value. The developed model can be used in order to solve the planning problems of railway transport development.
Optimizing the Project Development in Transportation Systems: Economical and Mathematical Models
Simeon Schreiber
2003-07-01
Full Text Available Construction of high-speed transportation systems often requirescalendar planning of the job complex. This paper describesan optimized model of construction project, which includestime parameters as well as cost factors. Project optimizationcan be achieved by solving the following two problems:1 minimizing expenditures within the predetermined durationof construction;2 determining the minimum duration of project constructionunder the set spending level.Both tasks are based on the idea of reducing the duration ofcertain sequence of operations down to the set level, ensuringthe highest effect of accelerating the construction. Under theknown time-cost relationship, the optimal solution can be reducedto search for such types of activities within the networkmodel, acceleration of which is the most efficacious in terms ofboth spending and finishing the overall project. The algorithmfor solving the above problems using the network model of jobcomplex is offered in the current paper. This method can beused for planning and managing the work logistics/calendar inconstruction and related types of industry, for research and developmentprojects in other areas.
Optimal neighbor graph-based orthogonal tensor locality preserving projection for image recognition
Yuan, Sen; Mao, Xia
2016-11-01
As a typical multilinear dimensionality reduction (DR) method, tensor locality preserving projection (TLPP) has been successfully applied in many practical problems. However, TLPP depends mainly on preserving its local neighbor graph which often suffers from the following issues: (1) the neighbor graph is constructed with the Euclidean distance which fails to consider the relationships among different coordinates for tensor data; (2) the affinity matrix only focuses on the local structure information of samples while ignoring the existing label information; (3) the projection matrices are nonorthogonal, thus it is difficult to preserve the local manifold structure. To address these problems, a multilinear DR algorithm called optimal neighbor graph-based orthogonal tensor locality preserving projection (OG-OTLPP) is proposed. In OG-OTLPP, an optimal neighbor graph is first built according to tensor distance. Then the affinity matrix of data is defined by utilizing both the label information and the intrinsic local geometric properties of the data. Finally, in order to improve the manifold preserving ability, an efficient and stable scheme is designed to iteratively learn the orthogonal projections. We evaluate the proposed algorithm by applying it to image recognition. The experimental results on five public image databases demonstrate the effectiveness of our algorithm.
Wei, W. B.; Tan, L.; Jia, M. Q.; Pan, Z. K.
2017-01-01
The variational level set method is one of the main methods of image segmentation. Due to signed distance functions as level sets have to keep the nature of the functions through numerical remedy or additional technology in an evolutionary process, it is not very efficient. In this paper, a normal vector projection method for image segmentation using Chan-Vese model is proposed. An equivalent formulation of Chan-Vese model is used by taking advantage of property of binary level set functions and combining with the concept of convex relaxation. Threshold method and projection formula are applied in the implementation. It can avoid the above problems and obtain a global optimal solution. Experimental results on both synthetic and real images validate the effects of the proposed normal vector projection method, and show advantages over traditional algorithms in terms of computational efficiency.
无
2006-01-01
The recurrent neural network (RNN) model based on projective operator was studied. Different from the former study, the value region of projective operator in the neural network in this paper is a general closed convex subset of n-dimensional Euclidean space and it is not a compact convex set in general, that is, the value region of projective operator is probably unbounded. It was proved that the network has a global solution and its solution trajectory converges to some equilibrium set whenever objective function satisfies some conditions. After that, the model was applied to continuously differentiable optimization and nonlinear or implicit complementarity problems. In addition, simulation experiments confirm the efficiency of the RNN.
Water Use Optimization Toolset Project: Development and Demonstration Phase Draft Report
Gasper, John R. [Argonne National Laboratory; Veselka, Thomas D. [Argonne National Laboratory; Mahalik, Matthew R. [Argonne National Laboratory; Hayse, John W. [Argonne National Laboratory; Saha, Samrat [Argonne National Laboratory; Wigmosta, Mark S. [PNNL; Voisin, Nathalie [PNNL; Rakowski, Cynthia [PNNL; Coleman, Andre [PNNL; Lowry, Thomas S. [SNL
2014-05-19
This report summarizes the results of the development and demonstration phase of the Water Use Optimization Toolset (WUOT) project. It identifies the objective and goals that guided the project, as well as demonstrating potential benefits that could be obtained by applying the WUOT in different geo-hydrologic systems across the United States. A major challenge facing conventional hydropower plants is to operate more efficiently while dealing with an increasingly uncertain water-constrained environment and complex electricity markets. The goal of this 3-year WUOT project, which is funded by the U.S. Department of Energy (DOE), is to improve water management, resulting in more energy, revenues, and grid services from available water, and to enhance environmental benefits from improved hydropower operations and planning while maintaining institutional water delivery requirements. The long-term goal is for the WUOT to be used by environmental analysts and deployed by hydropower schedulers and operators to assist in market, dispatch, and operational decisions.
Huang, Daizheng; Wu, Zhihui
2017-01-01
Accurately predicting the trend of outpatient visits by mathematical modeling can help policy makers manage hospitals effectively, reasonably organize schedules for human resources and finances, and appropriately distribute hospital material resources. In this study, a hybrid method based on empirical mode decomposition and back-propagation artificial neural networks optimized by particle swarm optimization is developed to forecast outpatient visits on the basis of monthly numbers. The data outpatient visits are retrieved from January 2005 to December 2013 and first obtained as the original time series. Second, the original time series is decomposed into a finite and often small number of intrinsic mode functions by the empirical mode decomposition technique. Third, a three-layer back-propagation artificial neural network is constructed to forecast each intrinsic mode functions. To improve network performance and avoid falling into a local minimum, particle swarm optimization is employed to optimize the weights and thresholds of back-propagation artificial neural networks. Finally, the superposition of forecasting results of the intrinsic mode functions is regarded as the ultimate forecasting value. Simulation indicates that the proposed method attains a better performance index than the other four methods.
Huang, Daizheng; Wu, Zhihui
2017-01-01
Accurately predicting the trend of outpatient visits by mathematical modeling can help policy makers manage hospitals effectively, reasonably organize schedules for human resources and finances, and appropriately distribute hospital material resources. In this study, a hybrid method based on empirical mode decomposition and back-propagation artificial neural networks optimized by particle swarm optimization is developed to forecast outpatient visits on the basis of monthly numbers. The data outpatient visits are retrieved from January 2005 to December 2013 and first obtained as the original time series. Second, the original time series is decomposed into a finite and often small number of intrinsic mode functions by the empirical mode decomposition technique. Third, a three-layer back-propagation artificial neural network is constructed to forecast each intrinsic mode functions. To improve network performance and avoid falling into a local minimum, particle swarm optimization is employed to optimize the weights and thresholds of back-propagation artificial neural networks. Finally, the superposition of forecasting results of the intrinsic mode functions is regarded as the ultimate forecasting value. Simulation indicates that the proposed method attains a better performance index than the other four methods. PMID:28222194
Sarkar, Kanchan; Bhattacharyya, S P
2013-08-21
We propose and implement a simple adaptive heuristic to optimize the geometries of clusters of point charges or ions with the ability to find the global minimum energy configurations. The approach uses random mutations of a single string encoding the geometry and accepts moves that decrease the energy. Mutation probability and mutation intensity are allowed to evolve adaptively on the basis of continuous evaluation of past explorations. The resulting algorithm has been called Completely Adaptive Random Mutation Hill Climbing method. We have implemented this method to search through the complex potential energy landscapes of parabolically confined 3D classical Coulomb clusters of hundreds or thousands of charges--usually found in high frequency discharge plasmas. The energy per particle (EN∕N) and its first and second differences, structural features, distribution of the oscillation frequencies of normal modes, etc., are analyzed as functions of confinement strength and the number of charges in the system. Certain magic numbers are identified. In order to test the feasibility of the algorithm in cluster geometry optimization on more complex energy landscapes, we have applied the algorithm for optimizing the geometries of MgO clusters, described by Coulomb-Born-Mayer potential and finding global minimum of some Lennard-Jones clusters. The convergence behavior of the algorithm compares favorably with those of other existing global optimizers.
An Extension of the Optimal Homotopy Asymptotic Method to Coupled Schrödinger-KdV Equation
Hakeem Ullah
2014-01-01
Full Text Available We consider the approximate solution of the coupled Schrödinger-KdV equation by using the extended optimal homotopy asymptotic method (OHAM. We obtained the extended OHAM solution of the problem and compared with the exact, variational iteration method (VIM and homotopy perturbation method (HPM solutions. The obtained solution shows that extended OHAM is effective, simpler, easier, and explicit and gives a suitable way to control the convergence of the approximate solution.
Olin, M.; Rasilainen, K.; Itaelae, A. [and others
2011-08-15
In the report main results form a KYT2010 programme's project Coupled behaviour of bentonite buffer (PUSKURI) are presented. In THC modelling, Aku Itaelae made and published his Master of Science Thesis. Itaelae was able to successfully model the LOT-experiment. Additionally, he also listed problems and development proposals for THC-modelling of bentonite buffer. VTT and Numerola created in collaboration a model coupling saturation, diffusion and cation exchange; the model was implemented and tested in Numerrin, COMSOL and TOUGHREACT. Petri Jussila's PhD THM-model was implemented into COMSOL to facilitate further development. At GTK, the mineralogical characterisation of bentonite was planned. The previous THM model (Jussila's model) including only small deformations was successfully generalized to finite deformations in way at least formally preserving the original formalism. It appears that the theory allows also a possibility to include finite plastic deformations in the theory. In order to measure the relevant mechanical properties of compacted bentonite, two different experiments, namely hydrostatic compression experiment and one-dimensional compression experiment were designed. In the hydrostatic compression experiment, a cylindrical sample of compacted bentonite covered with liquid rubber coating is placed in the sample chamber equipped with a piston. The same device was also used in one-dimensional compression experiment. X-ray microtomographic techniques were used in order to study the basic mechanisms of water transport in bentonite. The preliminary results indicate that in the present experimental set-up, water transport is dominated by a dispersive mechanism such as diffusion of vapour in gas phase or diffusion of water in solid phase. (orig.)
Genovese, Katia; Lamberti, Luciano; Pappalettere, Carmine
2006-05-01
This paper presents a new hybrid technique for mechanical characterization of hyperelastic materials. The research is motivated by the fact that standard identification procedures based on the fitting of strain-stress curves determined experimentally from planar biaxial tests may be inaccurate for non-uniform states of deformation. Therefore, we propose an alternative approach where the difference Ω between the displacement field measured with Projection Moiré and its counterpart predicted by FEM is minimized using non-linear optimization algorithms that finally find unknown material properties. In order to check the feasibility of the new procedure, we considered a thin latex membrane modelling it as a two-parameter Mooney-Rivlin (MR) hyperelastic material. The Ω function is minimized either using optimization routines available in a commercial finite element package and by implementing a global optimizer able to deal with non-linearity and non-convexity included in the identification process. In order to check accuracy of optimization results, target values of MR constants for the latex specimen tested have previously been determined by fitting experimental stress-strain data gathered from a standard planar biaxial tension test. Results indicate that the present hybrid identification procedure can determine accurately properties of the hyperelastic material under investigation. In fact, the average residual error on displacements was less than 1% while the difference between the MR constants found with optimization and their target values was less than 3.5%.
Imminent ocean acidification projected with the NCAR global coupled carbon cycle-climate model
M. Steinacher
2008-11-01
Full Text Available Ocean acidification from the uptake of anthropogenic carbon is simulated for the industrial period and IPCC SRES emission scenarios A2 and B1 with a global coupled carbon cycle-climate model. Earlier studies identified seawater saturation state with respect to aragonite, a mineral phase of calcium carbonate, as a key variable governing impacts on corals and other shell-forming organisms. Globally in the A2 scenario, water saturated by more than 300%, considered suitable for coral growth, vanishes by 2070 AD (CO_{2}≈630 ppm, and the ocean volume fraction occupied by saturated water decreases from 42% to 25% over this century. The largest simulated pH changes worldwide occur in Arctic surface waters, where hydrogen ion concentration increases by up to 185%. Projected climate change amplifies the decrease in Arctic surface mean saturation and pH by more than 20%, mainly due to freshening and increased carbon uptake in response to sea ice retreat. Modeled saturation compares well with observation-based estimates along an Arctic transect and simulated changes have been corrected for remaining model-data differences in this region. Aragonite undersaturation in Arctic surface waters is projected to occur locally soon and to become more widespread as atmospheric CO_{2} continues to grow. The results imply that surface waters in the Arctic Ocean will become corrosive to aragonite, with potentially large implications for the marine ecosystem, if anthropogenic carbon emissions are not reduced and atmospheric CO_{2} not kept below 450 ppm.
Curotto, E; Freeman, David L; Doll, J D
2008-05-28
A Monte Carlo path integral method to study the coupling between the rotation and bending degrees of freedom for water is developed. It is demonstrated that soft internal degrees of freedom that are not stretching in nature can be mapped with stereographic projection coordinates. For water, the bending coordinate is orthogonal to the stereographic projection coordinates used to map its orientation. Methods are developed to compute the classical and quantum Jacobian terms so that the proper infinitely stiff spring constant limit is recovered in the classical limit, and so that the nonconstant nature of the Riemann Cartan curvature scalar is properly accounted in the quantum simulations. The theory is used to investigate the effects of the geometric coupling between the bending and the rotating degrees of freedom for the water monomer in an external field in the 250 to 500 K range. We detect no evidence of geometric coupling between the bending degree of freedom and the orientations.
Sadiq, Nausheen; Beauchemin, Diane
2014-12-03
Two different approaches were used to improve the capabilities of solid sampling (SS) electrothermal vaporization (ETV) coupled to inductively coupled plasma optical emission spectrometry (ICP-OES) for the direct analysis of powdered rice. Firstly, a cooling step immediately before and after the vaporization step in the ETV temperature program resulted in a much sharper analyte signal peak. Secondly, point-by-point internal standardization with an Ar emission line significantly improved the linearity of calibration curves obtained with an increasing amount of rice flour certified reference material (CRM). Under the optimized conditions, detection limits ranged from 0.01 to 6ngg(-1) in the solid, depending on the element and wavelength selected. The method was validated through the quantitative analysis of corn bran and wheat flour CRMs. Application of the method to the multi-elemental analysis of 4-mg aliquots of real organic long grain rice (white and brown) also gave results for Al, As, Co, Cu, Fe, Mg, Se, Pb and Zn in agreement with those obtained by inductively coupled plasma mass spectrometry following acid digestion of 0.2-g aliquots. As the analysis takes roughly 5min per sample (2.5min for grinding, 0.5-1min for weighing a 4-mg aliquot and 87s for the ETV program), this approach shows great promise for fast screening of food samples.
Coupled Model Intercomparison Project 5 (CMIP5) simulations of climate following volcanic eruptions
Driscoll, Simon
2012-09-16
The ability of the climate models submitted to the Coupled Model Intercomparison Project 5 (CMIP5) database to simulate the Northern Hemisphere winter climate following a large tropical volcanic eruption is assessed. When sulfate aerosols are produced by volcanic injections into the tropical stratosphere and spread by the stratospheric circulation, it not only causes globally averaged tropospheric cooling but also a localized heating in the lower stratosphere, which can cause major dynamical feedbacks. Observations show a lower stratospheric and surface response during the following one or two Northern Hemisphere (NH) winters, that resembles the positive phase of the North Atlantic Oscillation (NAO). Simulations from 13 CMIP5 models that represent tropical eruptions in the 19th and 20th century are examined, focusing on the large-scale regional impacts associated with the large-scale circulation during the NH winter season. The models generally fail to capture the NH dynamical response following eruptions. They do not sufficiently simulate the observed post-volcanic strengthened NH polar vortex, positive NAO, or NH Eurasian warming pattern, and they tend to overestimate the cooling in the tropical troposphere. The findings are confirmed by a superposed epoch analysis of the NAO index for each model. The study confirms previous similar evaluations and raises concern for the ability of current climate models to simulate the response of a major mode of global circulation variability to external forcings. This is also of concern for the accuracy of geoengineering modeling studies that assess the atmospheric response to stratosphere-injected particles.
Ocean response to volcanic eruptions in Coupled Model Intercomparison Project 5 simulations
Ding, Yanni
2014-09-01
We examine the oceanic impact of large tropical volcanic eruptions as they appear in ensembles of historical simulations from eight Coupled Model Intercomparison Project Phase 5 models. These models show a response that includes lowering of global average sea surface temperature by 0.1–0.3 K, comparable to the observations. They show enhancement of Arctic ice cover in the years following major volcanic eruptions, with long-lived temperature anomalies extending to the middepth and deep ocean on decadal to centennial timescales. Regional ocean responses vary, although there is some consistent hemispheric asymmetry associated with the hemisphere in which the eruption occurs. Temperature decreases and salinity increases contribute to an increase in the density of surface water and an enhancement in the overturning circulation of the North Atlantic Ocean following these eruptions. The strength of this overturning increase varies considerably from model to model and is correlated with the background variability of overturning in each model. Any cause/effect relationship between eruptions and the phase of El Niño is weak.
Different coupled atmosphere-recharge oscillator Low Order Models for ENSO: a projection approach.
Bianucci, Marco; Mannella, Riccardo; Merlino, Silvia; Olivieri, Andrea
2016-04-01
El Ninõ-Southern Oscillation (ENSO) is a large scale geophysical phenomenon where, according to the celebrated recharge oscillator model (ROM), the Ocean slow variables given by the East Pacific Sea Surface Temperature (SST) and the average thermocline depth (h), interact with some fast "irrelevant" ones, representing mostly the atmosphere (the westerly wind burst and the Madden-Julian Oscillation). The fast variables are usually inserted in the model as an external stochastic forcing. In a recent work (M. Bianucci, "Analytical probability density function for the statistics of the ENSO phenomenon: asymmetry and power law tail" Geophysical Research Letters, under press) the author, using a projection approach applied to general deterministic coupled systems, gives a physically reasonable explanation for the use of stochastic models for mimicking the apparent random features of the ENSO phenomenon. Moreover, in the same paper, assuming that the interaction between the ROM and the fast atmosphere is of multiplicative type, i.e., it depends on the SST variable, an analytical expression for the equilibrium density function of the anomaly SST is obtained. This expression fits well the data from observations, reproducing the asymmetry and the power law tail of the histograms of the NINÕ3 index. Here, using the same theoretical approach, we consider and discuss different kind of interactions between the ROM and the other perturbing variables, and we take into account also non linear ROM as a low order model for ENSO. The theoretical and numerical results are then compared with data from observations.
Chenel, A. [Laboratoire de Chimie Physique, UMR 8000 and CNRS, Université Paris-Sud, F-91405 Orsay (France); Meier, C. [Laboratoire Collisions, Agrégats, Réactivité, UMR 5589, IRSAMC, Université Paul Sabatier, F-31062 Toulouse (France); Dive, G. [Centre d’Ingéniérie des Protéines, Université de Liège, Sart Tilman, B6, B-4000 Liège (Belgium); Desouter-Lecomte, M. [Laboratoire de Chimie Physique, UMR 8000 and CNRS, Université Paris-Sud, F-91405 Orsay (France); Département de Chimie, Université de Liège, Bât B6c, Sart Tilman, B4000 Liège (Belgium)
2015-01-14
We compare the strategy found by the optimal control theory in a complex molecular system according to the active subspace coupled to the field. The model is the isomerization during a Cope rearrangement of Thiele’s ester that is the most stable dimer obtained by the dimerization of methyl-cyclopentadienenylcarboxylate. The crudest partitioning consists in retaining in the active space only the reaction coordinate, coupled to a dissipative bath of harmonic oscillators which are not coupled to the field. The control then fights against dissipation by accelerating the passage across the transition region which is very wide and flat in a Cope reaction. This mechanism has been observed in our previous simulations [Chenel et al., J. Phys. Chem. A 116, 11273 (2012)]. We compare here, the response of the control field when the reaction path is coupled to a second active mode. Constraints on the integrated intensity and on the maximum amplitude of the fields are imposed limiting the control landscape. Then, optimum field from one-dimensional simulation cannot provide a very high yield. Better guess fields based on the two-dimensional model allow the control to exploit different mechanisms providing a high control yield. By coupling the reaction surface to a bath, we confirm the link between the robustness of the field against dissipation and the time spent in the delocalized states above the transition barrier.
Lamy, Julian V.
Increasing the percentage of wind power in the United States electricity generation mix would facilitate the transition towards a more sustainable, low-pollution, and environmentally-conscious electricity grid. However, this effort is not without cost. Wind power generation is time-variable and typically not synchronized with electricity demand (i.e., load). In addition, the highest-output wind resources are often located in remote locations, necessitating transmission investment between generation sites and load. Furthermore, negative public perceptions of wind projects could prevent widespread wind development, especially for projects close to densely-populated communities. The work presented in my dissertation seeks to understand where it's best to locate wind energy projects while considering these various factors. First, in Chapter 2, I examine whether energy storage technologies, such as grid-scale batteries, could help reduce the transmission upgrade costs incurred when siting wind projects in distant locations. For a case study of a hypothetical 200 MW wind project in North Dakota that delivers power to Illinois, I present an optimization model that estimates the optimal size of transmission and energy storage capacity that yields the lowest average cost of generation and transmission (/MWh). I find that for this application of storage to be economical, energy storage costs would have to be 100/kWh or lower, which is well below current costs for available technologies. I conclude that there are likely better ways to use energy storage than for accessing distant wind projects. Following from this work, in Chapter 3, I present an optimization model to estimate the economics of accessing high quality wind resources in remote areas to comply with renewable energy policy targets. I include temporal aspects of wind power (variability costs and correlation to market prices) as well as total wind power produced from different farms. I assess the goal of providing
Modeling and Design Optimization of A Shaft-Coupled Motor and Magnetic Gear
R. Zanis
2016-03-01
Full Text Available This paper presents the modeling and design of an actuator consisting of an electrical motor and a magnetic gear. To minimize the overall actuator dimensions, both of the electromagnetic devices need to be optimally designed and matched. An issue in performing a simultaneous design as such arises from a high number of design variables that significantly increases the complexity of the optimization problem. A method to reduce the design variables is discussed in this paper, which is the application of response surface methodology (RSM to represent the optimized torques of the electrical motor and magnetic gear as polynomial functions of their respective dimensions. Prior to the application of RSM, optimization problem statements are defined for the electrical motor and magnetic gear, for which the optimization objective and constraint functions are derived from analytical electromagnetic models of the considered electromagnetic devices.
Optimized photovoltaic generator-water electrolyser coupling through a controlled DC-DC converter
Garcia-Valverde, R.; Miguel, C.; Urbina, A. [Universidad Politecnica de Cartagena, Departamento de Electronica, Tecnologia de Computadoras y Proyectos, Plaza del Hospital, 1, Cartagena, 30203 Murcia (Spain); Martinez-Bejar, R. [Universidad de Murcia, Departamento de Ingenieria de la Informacion y las Comunicaciones, Facultad de Informatica, Campus de Espinardo, 30071 Murcia (Spain)
2008-10-15
The coupling of a photovoltaic generator and an electrolyser is one of the most promising options for obtaining hydrogen from a renewable energy source. Both are well known technologies, however, since the high variability of the solar radiation, an efficient coupling still presents some challenges. Direct or through a DC-DC converter couplings are the options in isolated applications. In this work, three models, respectively, for a photovoltaic (PV) generator, a controlled DC-DC converter and a complete proton exchange membrane (PEM) electrolyser have been designed by using Matlab/Simulink. A PV-electrolyser specific algorithm to search for the optimum and safe working point for both elements is presented. Simulation results demonstrate that the use of a controlled DC-DC converter with the proposed algorithm shows better adaptability to the variable radiation conditions than the other coupling options. Therefore, it leads to a better compliance between the electrolyser and the sizing of the PV generator. (author)
Optimization of Italian CMS Computing Centers via MIUR funded Research Projects
Boccali, Tommaso
2014-01-01
The Italian Ministry of Research (MIUR) funded in the past years research projects aimed to an optimization of the analysis activities in the Italian CMS computing Centers. A new grant started in 2013, and activities are already ongoing in 9 INFN sites, all hosting local CMS groups. Main focus will be on the creation of an italian storage federation (via Xrootd initially, and later HTTP) which allows all the italian CMS physicists to a privileged access to CMS data and simulations. Another task will focus on the optimization of the last step of a CMS analysis, via interactive access to resources; this will result in a number of small- to medium-sized analysis centers, where access will be granted at national level to multicore machines, PROOF facilities, high throughput local queues. An important part of this last activity will imply experimenting with on demand analysis machine instantiation via Clouds, using the experience and the resources INFN is building on the subject.
Gradient methods for variational optimization of projected entangled-pair states
Vanderstraeten, Laurens; Haegeman, Jutho; Corboz, Philippe; Verstraete, Frank
2016-10-01
We present a conjugate-gradient method for the ground-state optimization of projected entangled-pair states (PEPS) in the thermodynamic limit, as a direct implementation of the variational principle within the PEPS manifold. Our optimization is based on an efficient and accurate evaluation of the gradient of the global energy functional by using effective corner environments, and is robust with respect to the initial starting points. It has the additional advantage that physical and virtual symmetries can be straightforwardly implemented. We provide the tools to compute static structure factors directly in momentum space, as well as the variance of the Hamiltonian. We benchmark our method on Ising and Heisenberg models, and show a significant improvement on the energies and order parameters as compared to algorithms based on imaginary-time evolution.
Optimal coupling of entangled photons into single-mode optical fibers
Andrews, R; Sarkar, S; Sarkar, Sarben
2004-01-01
We present a consistent multimode theory that describes the coupling of single photons generated by collinear Type-I parametric down-conversion into single-mode optical fibers. We have calculated an analytic expression for the fiber diameter which maximizes the pair photon count rate. For a given focal length and wavelength, a lower limit of the fiber diameter for satisfactory coupling is obtained.
HIFI-C: a robust and fast method for determining NMR couplings from adaptive 3D to 2D projections.
Cornilescu, Gabriel; Bahrami, Arash; Tonelli, Marco; Markley, John L; Eghbalnia, Hamid R
2007-08-01
We describe a novel method for the robust, rapid, and reliable determination of J couplings in multi-dimensional NMR coupling data, including small couplings from larger proteins. The method, "High-resolution Iterative Frequency Identification of Couplings" (HIFI-C) is an extension of the adaptive and intelligent data collection approach introduced earlier in HIFI-NMR. HIFI-C collects one or more optimally tilted two-dimensional (2D) planes of a 3D experiment, identifies peaks, and determines couplings with high resolution and precision. The HIFI-C approach, demonstrated here for the 3D quantitative J method, offers vital features that advance the goal of rapid and robust collection of NMR coupling data. (1) Tilted plane residual dipolar couplings (RDC) data are collected adaptively in order to offer an intelligent trade off between data collection time and accuracy. (2) Data from independent planes can provide a statistical measure of reliability for each measured coupling. (3) Fast data collection enables measurements in cases where sample stability is a limiting factor (for example in the presence of an orienting medium required for residual dipolar coupling measurements). (4) For samples that are stable, or in experiments involving relatively stronger couplings, robust data collection enables more reliable determinations of couplings in shorter time, particularly for larger biomolecules. As a proof of principle, we have applied the HIFI-C approach to the 3D quantitative J experiment to determine N-C' RDC values for three proteins ranging from 56 to 159 residues (including a homodimer with 111 residues in each subunit). A number of factors influence the robustness and speed of data collection. These factors include the size of the protein, the experimental set up, and the coupling being measured, among others. To exhibit a lower bound on robustness and the potential for time saving, the measurement of dipolar couplings for the N-C' vector represents a realistic
A Coupled Programme of Aerosol Research Within the OP3 and ACES Projects
McFiggans, G.; Aces Aerosol Teams, P A
2008-12-01
The oxidation of organic compounds in the troposphere plays a central role in the generation of ozone, and leads to the formation of secondary organic aerosol (SOA) and other secondary pollutants. Approximately 90% of organic material emitted globally is estimated to originate from biogenic sources, with almost half of all reactive biogenic volatile organic compounds (BVOC) being emitted from tropical and sub-tropical forests. It is becoming increasingly clear from observational studies that biogenic SOA (BSOA) is the dominant source of aerosol organic carbon concentrations in remote environments. This provides part of the motivation for the OP3 project. Ground-based aerosol measurements at the Global Atmosphere Watch (GAW) site in Danum Valley Conservation Area in OP3 were provided by a suite of instrumentation for full composition and physical property characterisation (size distribution, hygroscopicity and CCN activation). To further enhance our understanding of aerosol processes in the Borneo rainforest, additional capability was assembled within the UK NERC funded "Aerosol Coupling in the Earth System" (ACES) programme. Field component enhancements to the OP3 aerosol payload by ACES included a deployment of aerosol and precursor flux measurements within the forest canopy to characterise primary bioaerosol sources and in-canopy chemistry leading to formation of secondary aerosol components. In addition, measurements of VOCs and aerosol composition were made above an oil palm plantation to assess the impact of land-use change on aerosol processes. ACES is a coupled programme of field, chamber, mechanism development and modelling investigations aiming to reduce uncertainties in our fundamental understanding of BSOA formation and the subsequent impact on atmospheric composition. In addition to summarising aerosol field measurements within ACES / OP3, we will present an overview of the status of the ACES chamber and modelling results with the overall aim to: i
Story, T Nathan; Berg, Cynthia A; Smith, Timothy W; Beveridge, Ryan; Henry, Nancy J M; Pearce, Gale
2007-12-01
This study examined whether positive sentiment override (greater positive appraisal of spouse's affiliative behavior than is warranted by observed behavior) occurred more frequently in older compared with middle-aged married couples and whether age differences were mediated by older adults' greater marital satisfaction when controlling for optimism. Participants included 270 middle-aged (40-50 years old) and older (60-70 years old) couples who discussed a marital disagreement and completed an errand task. Couples provided appraisals of their spouse's affiliation, and the authors coded affiliative interactions using the structural analysis of social behavior. Hierarchical multivariate linear modeling indicated that older husbands and wives viewed their spouse's behavior as more positive during disagreement interactions than did independent observers; in the errand task, only older wives demonstrated positive sentiment override. Age differences in positive sentiment override were mediated by marital satisfaction, even when controlling for optimism. The results are consistent with theories of emotion regulation, such as socioemotional selectivity theory, that suggest that older adults are biased toward the positive aspects of close relationships.
Optimization of Printed Antennas Using Genetic Algorithm Coupled with Improved Cavity Model
Sathi, Vahid; Ehteshami, Nasrin; Ghobadi, C.
2012-06-01
An accurate electromagnetic optimization tool for designing rectangular and circular microstrip antennas is proposed. This optimization method is based on the improved cavity model analysis in conjunction with the well-known genetic algorithm, which is employed to optimize the dimensions and feed point location of rectangular and circular microstrip antennas. Results obtained by this technique agree quite well with the measured data and the data obtained by the FEM based software HFSS by ANSOFT. This technique can be fruitfully used in microwave CAD applications.
Eyring, Veronika; Bony, Sandrine; Meehl, Gerald A.; Senior, Catherine A.; Stevens, Bjorn; Stouffer, Ronald J.; Taylor, Karl E.
2016-05-01
By coordinating the design and distribution of global climate model simulations of the past, current, and future climate, the Coupled Model Intercomparison Project (CMIP) has become one of the foundational elements of climate science. However, the need to address an ever-expanding range of scientific questions arising from more and more research communities has made it necessary to revise the organization of CMIP. After a long and wide community consultation, a new and more federated structure has been put in place. It consists of three major elements: (1) a handful of common experiments, the DECK (Diagnostic, Evaluation and Characterization of Klima) and CMIP historical simulations (1850-near present) that will maintain continuity and help document basic characteristics of models across different phases of CMIP; (2) common standards, coordination, infrastructure, and documentation that will facilitate the distribution of model outputs and the characterization of the model ensemble; and (3) an ensemble of CMIP-Endorsed Model Intercomparison Projects (MIPs) that will be specific to a particular phase of CMIP (now CMIP6) and that will build on the DECK and CMIP historical simulations to address a large range of specific questions and fill the scientific gaps of the previous CMIP phases. The DECK and CMIP historical simulations, together with the use of CMIP data standards, will be the entry cards for models participating in CMIP. Participation in CMIP6-Endorsed MIPs by individual modelling groups will be at their own discretion and will depend on their scientific interests and priorities. With the Grand Science Challenges of the World Climate Research Programme (WCRP) as its scientific backdrop, CMIP6 will address three broad questions: - How does the Earth system respond to forcing? - What are the origins and consequences of systematic model biases? - How can we assess future climate changes given internal climate variability, predictability, and uncertainties in
Liang, Xin-xin; Zhang, Nai-min; Zhang, Yan
2016-07-01
For solid launch vehicle performance promotion, a modeling method of interior and exterior ballistics associated optimization with constraints of attitude control and mechanical-thermal condition is proposed. Firstly, the interior and external ballistic models of the solid launch vehicle are established, and the attitude control model of the high wind area and the stage of the separation is presented, and the load calculation model of the drag reduction device is presented, and thermal condition calculation model of flight is presented. Secondly, the optimization model is established to optimize the range, which has internal and external ballistic design parameters as variables selected by sensitivity analysis, and has attitude control and mechanical-thermal conditions as constraints. Finally, the method is applied to the optimal design of a three stage solid launch vehicle simulation with differential evolution algorithm. Simulation results are shown that range capability is improved by 10.8%, and both attitude control and mechanical-thermal conditions are satisfied.
Komly, Claude-Emma; Azzaro-Pantel, Catherine; Hubert, Antoine; Pibouleau, Luc; Archambault, Valérie
2012-01-01
International audience; A mathematical model based on life-cycle assessment (LCA) results is developed to assess the environmental efficiency of the end-of-life management of polyethylene terephthalate (PET) bottles. For this purpose, multiobjective optimization and decision support tools are used to define optimal targets for efficient waste management. The global environmental impacts associated with the treatment of PET bottles from their cradle to their ultimate graves (incineration, land...
Cost-optimal power system extension under flow-based market coupling
Hagspiel, Simeon; Jaegemann, Cosima; Lindenberger, Dietmar [Koeln Univ. (Germany). Energiewirtschaftliches Inst.; Brown, Tom; Cherevatskiy, Stanislav; Troester, Eckehard [Energynautics GmbH, Langen (Germany)
2013-05-15
Electricity market models, implemented as dynamic programming problems, have been applied widely to identify possible pathways towards a cost-optimal and low carbon electricity system. However, the joint optimization of generation and transmission remains challenging, mainly due to the fact that different characteristics and rules apply to commercial and physical exchanges of electricity in meshed networks. This paper presents a methodology that allows to optimize power generation and transmission infrastructures jointly through an iterative approach based on power transfer distribution factors (PTDFs). As PTDFs are linear representations of the physical load flow equations, they can be implemented in a linear programming environment suitable for large scale problems. The algorithm iteratively updates PTDFs when grid infrastructures are modified due to cost-optimal extension and thus yields an optimal solution with a consistent representation of physical load flows. The method is first demonstrated on a simplified three-node model where it is found to be robust and convergent. It is then applied to the European power system in order to find its cost-optimal development under the prescription of strongly decreasing CO{sub 2} emissions until 2050.
Timothy B Hallett
2011-11-01
Full Text Available BACKGROUND: Antiretrovirals have substantial promise for HIV-1 prevention, either as antiretroviral treatment (ART for HIV-1-infected persons to reduce infectiousness, or as pre-exposure prophylaxis (PrEP for HIV-1-uninfected persons to reduce the possibility of infection with HIV-1. HIV-1 serodiscordant couples in long-term partnerships (one member is infected and the other is uninfected are a priority for prevention interventions. Earlier ART and PrEP might both reduce HIV-1 transmission in this group, but the merits and synergies of these different approaches have not been analyzed. METHODS AND FINDINGS: We constructed a mathematical model to examine the impact and cost-effectiveness of different strategies, including earlier initiation of ART and/or PrEP, for HIV-1 prevention for serodiscordant couples. Although the cost of PrEP is high, the cost per infection averted is significantly offset by future savings in lifelong treatment, especially among couples with multiple partners, low condom use, and a high risk of transmission. In some situations, highly effective PrEP could be cost-saving overall. To keep couples alive and without a new infection, providing PrEP to the uninfected partner could be at least as cost-effective as initiating ART earlier in the infected partner, if the annual cost of PrEP is 70% effective. CONCLUSIONS: Strategic use of PrEP and ART could substantially and cost-effectively reduce HIV-1 transmission in HIV-1 serodiscordant couples. New and forthcoming data on the efficacy of PrEP, the cost of delivery of ART and PrEP, and couples behaviours and preferences will be critical for optimizing the use of antiretrovirals for HIV-1 prevention. Please see later in the article for the Editors' Summary.
Yao, Jiannan; Deng, Yong; Xiao, Xingming
2017-01-01
To avoid catenary collision in a multi-rope friction mine hoist, in this study, the relevant hoisting parameters based on the multi-source coupled vibration characteristics of hoisting catenaries are optimized...
Optimization Research on Valve Hall Grounding Switch Arrangement of UHVDC Project
CAO Yanming; NIE Dingzhen; MA Weimin
2012-01-01
The switches installed in converter station valve halls in Xiangjiaba-Shanghai ± 800 kV UHVDC project are expensive and maintenance inconvenience. Two optimization schemes of the valve hall grounding switches for researches on the function and operation of the switchers are presented. The two schemes are both studied in detail, with one way of abolishing all grounding switches on transformer valve side, and another way of partly cancelling the switches. Detailed analysis is further carried out for the feasibility and the pros and cons of the two schemes. Based on the comparison of two schemes, the partial reduction of grounding switches is selected to get a simulation with an EMTDC model. Plus in order to verify the reliability of the simulating results, a field test is carried out in Fengxian converter station with the partly switches cancellation scheme. The test results proved that using only one switch can still release residual charge in the valve hall in a relatively short period. Optimized designs of the valve hall switches can save both space and costs of the project.
Ukwatta, Eranga; Yuan, Jing; Rajchl, Martin; Fenster, Aaron
2012-01-01
Magnetic resonance (MR) imaging of carotid atherosclerosis biomarkers are increasingly being investigated for the risk assessment of vulnerable plaques. A fast and robust 3D segmentation of the carotid adventitia (AB) and lumen-intima (LIB) boundaries can greatly alleviate the measurement burden of generating quantitative imaging biomarkers in clinical research. In this paper, we propose a novel global optimization-based approach to segment the carotid AB and LIB from 3D T1-weighted black blood MR images, by simultaneously evolving two coupled surfaces with enforcement of anatomical consistency of the AB and LIB. We show that the evolution of two surfaces at each discrete time-frame can be optimized exactly and globally by means of convex relaxation. Our continuous max-flow based algorithm is implemented in GPUs to achieve high computational performance. The experiment results from 16 carotid MR images show that the algorithm obtained high agreement with manual segmentations and achieved high repeatability in segmentation.
Hindi, Haitham; Prabhakar, Shyam; Fox, John D.; Linscott, Ivan; Teytelman, Dmitri; /SLAC
2011-08-31
We present a technique for the design and verification of efficient bunch-by-bunch controllers for damping longitudinal multibunch instabilities. The controllers attempt to optimize the use of available feedback amplifier power - one of the most expensive components of a feedback system - and define the limits of the closed loop system performance. Our design technique alternates between analytic computation of single bunch optimal controllers and verification on a multibunch numerical simulator. The simulator uses PEP-II parameters and identifies unstable coupled bunch modes, their growth rates and their damping rates with feedback. The results from the simulator are shown to be in reasonable agreement with analytical calculations based on the single bunch model. The technique is then used to evaluate the performance of a variety of controllers proposed for PEP-II.
Sutton, N.B.; Grotenhuis, J.T.C.; Langenhoff, A.A.M.; Rijnaarts, H.H.M.
2011-01-01
Purpose - In order to provide highly effective yet relatively inexpensive strategies for the remediation of recalcitrant organic contaminants, research has focused on in situ treatment technologies. Recent investigation has shown that coupling two common treatments-in situ chemical oxidation (ISCO)
Optimal stopping of multi-project software testing in the context of software cybernetics
蔡开元
2003-01-01
Software cybernetics explores the interplay between control theory/engineering and software theory/engineering. The controlled Markov chains (CMC) approach to software testing follows the idea of software cybernetics and treats software testing as a control problem. The software under test serves as a controlled object and the software testing strategy serves as the corresponding controller. The software under test and the software testing strategy make up a closed-loop feedback control system, and the the-ory of controlled Markov chains can be used to design and optimize software testing strategies in accor-dance with testing/reliability goals given a priori. In this paper we apply the CMC approach to the optimal stopping problem of multi-project software testing. The problem under consideration assumes that a sin-gle stopping action can stop testing of all the software systems under test simultaneously. The theoretical results presented in this paper describe how to test multiple software systems and when to stop testing in an optimal manner. An illustrative example is used to explain the theoretical results. The study of this paper further justifies the effectiveness of the CMC approach to software testing in particular and the idea of software cybernetics in general.
Iterative projection on critical states for reliability-based design optimization
Croquet, R.; Lemosse, D.; Souza de Cursi, E.; El Hami, A.
2013-05-01
Reliability-Based Design Optimization (RBDO) has been developed to design structures that reach the best compromise between cost reduction and reliability by considering uncertainties. This is achieved by reformulating the initial optimization problem in order to introduce probabilistic constraints. Numerical evaluation of these constraints by direct approaches turns out to be difficult: estimation of probability of failure implies calculation of multidimensional integrals. The integrals often rely on complex models whose evaluation is time-consuming. In this article, the RBDO framework is used to propose a new approach. For this purpose, a method to project a deterministic optimal solution onto a reliable domain is provided. This is achieved by a two-step iterative scheme. A sensitivity analysis identifies a critical situation. The latter leads to an adapted reliable safety domain. This new area is used to define a reliable design through a Newton-like process. Corresponding safety margins can be easily interpreted as partial safety factors. Finally, numerical applications in engineering are discussed to show the efficiency and the interest of the proposed algorithm.
A planning support system to optimize approval of private housing development projects
Hussnain, M. Q.; Wakil, K.; Waheed, A.; Tahir, A.
2016-06-01
Out of 182 million population of Pakistan, 38% reside in urban areas having an average growth rate of 1.6%, raising the urban housing demand significantly. Poor state response to fulfil the housing needs has resulted in a mushroom growth of private housing schemes (PHS) over the years. Consequently, only in five major cities of Punjab, there are 383 legal and 150 illegal private housing development projects against 120 public sector housing schemes. A major factor behind the cancerous growth of unapproved PHS is the prolonged and delayed approval process in concerned approval authorities requiring 13 months on average. Currently, manual and paper-based approaches are used for vetting and for granting the permission which is highly subjective and non-transparent. This study aims to design a flexible planning support system (PSS) to optimize the vetting process of PHS projects under any development authority in Pakistan by reducing time and cost required for site and documents investigations. Relying on the review of regulatory documents and interviews with professional planners and land developers, this study describes the structure of a PSS developed using open- source geo-spatial tools such as OpenGeo Suite, PHP, and PostgreSQL. It highlights the development of a Knowledge Module (based on regulatory documents) containing equations related to scheme type, size (area), location, access road, components of layout plan, planning standards and other related approval checks. Furthermore, it presents the architecture of the database module and system data requirements categorized as base datasets (built-in part of PSS) and input datasets (related to the housing project under approval). It is practically demonstrated that developing a customized PSS to optimize PHS approval process in Pakistan is achievable with geospatial technology. With the provision of such a system, the approval process for private housing schemes not only becomes quicker and user-friendly but also
Davidsen, Claus; Liu, Suxia; Mo, Xingguo; Engelund Holm, Peter; Trapp, Stefan; Rosbjerg, Dan; Bauer-Gottwein, Peter
2015-04-01
Few studies address water quality in hydro-economic models, which often focus primarily on optimal allocation of water quantities. Water quality and water quantity are closely coupled, and optimal management with focus solely on either quantity or quality may cause large costs in terms of the oth-er component. In this study, we couple water quality and water quantity in a joint hydro-economic catchment-scale optimization problem. Stochastic dynamic programming (SDP) is used to minimize the basin-wide total costs arising from water allocation, water curtailment and water treatment. The simple water quality module can handle conservative pollutants, first order depletion and non-linear reactions. For demonstration purposes, we model pollutant releases as biochemical oxygen demand (BOD) and use the Streeter-Phelps equation for oxygen deficit to compute the resulting min-imum dissolved oxygen concentrations. Inelastic water demands, fixed water allocation curtailment costs and fixed wastewater treatment costs (before and after use) are estimated for the water users (agriculture, industry and domestic). If the BOD concentration exceeds a given user pollution thresh-old, the user will need to pay for pre-treatment of the water before use. Similarly, treatment of the return flow can reduce the BOD load to the river. A traditional SDP approach is used to solve one-step-ahead sub-problems for all combinations of discrete reservoir storage, Markov Chain inflow clas-ses and monthly time steps. Pollution concentration nodes are introduced for each user group and untreated return flow from the users contribute to increased BOD concentrations in the river. The pollutant concentrations in each node depend on multiple decision variables (allocation and wastewater treatment) rendering the objective function non-linear. Therefore, the pollution concen-tration decisions are outsourced to a genetic algorithm, which calls a linear program to determine the remainder of the decision
SHAPE STABILITY OF OPTIMAL CONTROL PROBLEMS IN COEFFICIENTS FOR COUPLED SYSTEM OF HAMMERSTEIN TYPE
P. I. Kogut
2014-01-01
Full Text Available In this paper we consider an optimal control problem (OCP for the coupledsystem of a nonlinear monotone Dirichlet problem with matrix-valued L∞(Ω;RN×N-controls in coecients and a nonlinear equation of Hammerstein type, where solution nonlinearly depends on L∞ -control. Since problems of this type have no solutions in general, we make a special assumption on the coecients of the state equations and introduce the class of so-called solenoidal admissible controls. Using the direct method in calculus of variations, we prove the existence of an optimal control. We also study the stability of the optimal control problem with respect to the domain perturbation. In particular, we derive the sucient conditions of the Mosco-stability for the given class of OCPs.
Riva, M.
2012-09-01
The design of astronomical instrument is growing in dimension and complexity following ELT class telescopes. The availability of new structural material like composite ones is asking for more robust and reliable designing numerical tools. This paper wants to show a new opto-mechanical optimization approach developed starting from a previously developed integrated design framework. The Idea is to reduce number of iteration in a multi- variable structural optimization taking advantage of the embedded sensitivity routines that are available both in FEA software and in raytracing ones. This approach provide reduced iteration number mainly in case of high number of structural variable parameters.
Degroote, Matthias; Henderson, Thomas M.; Zhao, Jinmo; Dukelsky, Jorge; Scuseria, Gustavo E.
2016-03-01
We present a similarity transformation theory based on a polynomial form of a particle-hole pair excitation operator. In the weakly correlated limit, this polynomial becomes an exponential, leading to coupled cluster doubles. In the opposite strongly correlated limit, the polynomial becomes an extended Bessel expansion and yields the projected BCS wave function. In between, we interpolate using a single parameter. The effective Hamiltonian is non-Hermitian and this polynomial similarity transformation theory follows the philosophy of traditional coupled cluster, left projecting the transformed Hamiltonian onto subspaces of the Hilbert space in which the wave function variance is forced to be zero. Similarly, the interpolation parameter is obtained through minimizing the next residual in the projective hierarchy. We rationalize and demonstrate how and why coupled cluster doubles is ill suited to the strongly correlated limit, whereas the Bessel expansion remains well behaved. The model provides accurate wave functions with energy errors that in its best variant are smaller than 1% across all interaction strengths. The numerical cost is polynomial in system size and the theory can be straightforwardly applied to any realistic Hamiltonian.
The Optimal Income Taxation of Couples as a Multi-Dimensional Screening Problem
Kleven, Henrik Jacobsen; Kreiner, Claus Thustrup; Saez, Emmanuel
problem. We prove that, under regularity and separability assumptions for utility functions and for a wide class of social welfare functions, optimal tax schemes display negative jointness such that the tax rate on one person decreases in the earnings of the spouse. We also show that the tax...
Optimizing investments in coupled offshore wind -electrolytic hydrogen storage systems in Denmark
Hou, Peng; Enevoldsen, Peter; Eichman, Joshua
2017-01-01
In response to electricity markets with growing levels of wind energy production and varying electricity prices, this research examines incentives for investments in integrated renewable energy power systems. A strategy for using optimization methods for a power system consisting of wind turbines...
Optimization of conventional rule curves coupled with hedging rules for reservoir operation
Taghian, Mehrdad; Rosbjerg, Dan; Haghighi, Ali;
2014-01-01
to achieve the optimal water allocation and the target storage levels for reservoirs. As a case study, a multipurpose, multireservoir system in southern Iran is selected. The results show that the model has good performance in extracting the optimum policy for reservoir operation under both normal...
Final report on LDRD project : coupling strategies for multi-physics applications.
Hopkins, Matthew Morgan; Moffat, Harry K.; Carnes, Brian; Hooper, Russell Warren; Pawlowski, Roger P.
2007-11-01
Many current and future modeling applications at Sandia including ASC milestones will critically depend on the simultaneous solution of vastly different physical phenomena. Issues due to code coupling are often not addressed, understood, or even recognized. The objectives of the LDRD has been both in theory and in code development. We will show that we have provided a fundamental analysis of coupling, i.e., when strong coupling vs. a successive substitution strategy is needed. We have enabled the implementation of tighter coupling strategies through additions to the NOX and Sierra code suites to make coupling strategies available now. We have leveraged existing functionality to do this. Specifically, we have built into NOX the capability to handle fully coupled simulations from multiple codes, and we have also built into NOX the capability to handle Jacobi Free Newton Krylov simulations that link multiple applications. We show how this capability may be accessed from within the Sierra Framework as well as from outside of Sierra. The critical impact from this LDRD is that we have shown how and have delivered strategies for enabling strong Newton-based coupling while respecting the modularity of existing codes. This will facilitate the use of these codes in a coupled manner to solve multi-physic applications.
Kerrigan, S; Brooks, D E
1998-01-01
A photoreactive heterobifunctional linker was used to prepare an immunogen in which lysergic acid diethylamide was indirectly coupled to keyhole limpet hemocyanin at multiple sites on the drug. It was possible to attach approximately 35 drug molecules to each protein using approximately equal amounts of both species during the reaction. The presence of buffer components or water severely compromised reaction efficiency, as estimated from the molar substitution ratio. Factors such as excess linker, pH, irradiation of dry matrix in the absence of buffer, and the drug/protein ratio used during photolysis were shown to have pronounced effects on reaction efficiency. Structural insights regarding immunogen coupling were obtained by determining the specificities of antibodies which were raised against the immunogen. Cross-reactivity data indicated that haptenation of protein likely occurred at positions N1 and N6 of lysergic acid diethylamide, which is plausible given the electrophilicity of the photogenerated aryl nitrene.
Chao, Ming; Wei, Jie; Li, Tianfang; Yuan, Yading; Rosenzweig, Kenneth E.; Lo, Yeh-Chi
2016-04-01
We present a study of extracting respiratory signals from cone beam computed tomography (CBCT) projections within the framework of the Amsterdam Shroud (AS) technique. Acquired prior to the radiotherapy treatment, CBCT projections were preprocessed for contrast enhancement by converting the original intensity images to attenuation images with which the AS image was created. An adaptive robust z-normalization filtering was applied to further augment the weak oscillating structures locally. From the enhanced AS image, the respiratory signal was extracted using a two-step optimization approach to effectively reveal the large-scale regularity of the breathing signals. CBCT projection images from five patients acquired with the Varian Onboard Imager on the Clinac iX System Linear Accelerator (Varian Medical Systems, Palo Alto, CA) were employed to assess the proposed technique. Stable breathing signals can be reliably extracted using the proposed algorithm. Reference waveforms obtained using an air bellows belt (Philips Medical Systems, Cleveland, OH) were exported and compared to those with the AS based signals. The average errors for the enrolled patients between the estimated breath per minute (bpm) and the reference waveform bpm can be as low as -0.07 with the standard deviation 1.58. The new algorithm outperformed the original AS technique for all patients by 8.5% to 30%. The impact of gantry rotation on the breathing signal was assessed with data acquired with a Quasar phantom (Modus Medical Devices Inc., London, Canada) and found to be minimal on the signal frequency. The new technique developed in this work will provide a practical solution to rendering markerless breathing signal using the CBCT projections for thoracic and abdominal patients.
Rohde, Sean E.
This document outlines the research performed on the design, manufacturing, modeling, and experimental testing of composite shafts possessing bend-twist coupling. A novel design for achieving this bend-twist coupling is presented. Closed form solutions modeling the behavior are derived for predicting the deformations of both tapered and non-tapered shafts possessing this novel design. The design and manufacturing of these shafts are detailed along with solutions to common problems faced. An experimental technique for quantifying the bend-twist coupling present in these shafts, using digital image correlation, is detailed. To understand how the shaft deforms under thermal changes, three separate analytical models are derived from three separate sets of assumptions. These are then compared to finite element analysis. Torsion experiments are performed on these shafts to determine the torsional strength and study how failure occurs. Micrographs were taken of these fractured shafts to observe the locations and manner of fracture. The design of these shafts is optimized as a function of performance objectives. Recommendations are then made for directions of future work.
GUO Fang-qiu; HUANG Lan-fang; ZHOU Huo-fei; JIANG Qiu-ju
2006-01-01
Uniform design was used to optimize extraction condition of direct refluence extraction of coumarins from the Chinese traditional medicine of radix angelicae pubescentis(Duhuo); the sum peak area of coumarins separated with high performance liquid chromatography(HPLC) at detection wavelength of 320 nm was considered as detection index, two factors of solvent concentration and extraction time were mainly studied at extraction temperature of 85 ℃ and a volume ratio of solvent to sample of 10: 1. Optimal subclass, quadric polynomial step by step aggression and neural network method were applied to process the experimental results. The results show that the first and second methods give the same factors combination (concentration of ethanol: 95 %, extraction time: 3.6 h) and the second method is much better than the first one. The extraction model is consequently developed.
Sobieszczanski-Sobieski, J.; Bhat, R. B.
1979-01-01
A finite element program is linked with a general purpose optimization program in a 'programing system' which includes user supplied codes that contain problem dependent formulations of the design variables, objective function and constraints. The result is a system adaptable to a wide spectrum of structural optimization problems. In a sample of numerical examples, the design variables are the cross-sectional dimensions and the parameters of overall shape geometry, constraints are applied to stresses, displacements, buckling and vibration characteristics, and structural mass is the objective function. Thin-walled, built-up structures and frameworks are included in the sample. Details of the system organization and characteristics of the component programs are given.
Optimization of dual-energy CT acquisitions for proton therapy using projection-based decomposition.
Vilches-Freixas, Gloria; Létang, Jean Michel; Ducros, Nicolas; Rit, Simon
2017-09-01
Dual-energy computed tomography (DECT) has been presented as a valid alternative to single-energy CT to reduce the uncertainty of the conversion of patient CT numbers to proton stopping power ratio (SPR) of tissues relative to water. The aim of this work was to optimize DECT acquisition protocols from simulations of X-ray images for the treatment planning of proton therapy using a projection-based dual-energy decomposition algorithm. We have investigated the effect of various voltages and tin filtration combinations on the SPR map accuracy and precision, and the influence of the dose allocation between the low-energy (LE) and the high-energy (HE) acquisitions. For all spectra combinations, virtual CT projections of the Gammex phantom were simulated with a realistic energy-integrating detector response model. Two situations were simulated: an ideal case without noise (infinite dose) and a realistic situation with Poisson noise corresponding to a 20 mGy total central dose. To determine the optimal dose balance, the proportion of LE-dose with respect to the total dose was varied from 10% to 90% while keeping the central dose constant, for four dual-energy spectra. SPR images were derived using a two-step projection-based decomposition approach. The ranges of 70 MeV, 90 MeV, and 100 MeV proton beams onto the adult female (AF) reference computational phantom of the ICRP were analytically determined from the reconstructed SPR maps. The energy separation between the incident spectra had a strong impact on the SPR precision. Maximizing the incident energy gap reduced image noise. However, the energy gap was not a good metric to evaluate the accuracy of the SPR. In terms of SPR accuracy, a large variability of the optimal spectra was observed when studying each phantom material separately. The SPR accuracy was almost flat in the 30-70% LE-dose range, while the precision showed a minimum slightly shifted in favor of lower LE-dose. Photon noise in the SPR images (20 mGy dose
ZHU Detong
2006-01-01
In this paper,we propose a new trust-region-projected Hessian algorithm with nonmonotonic backtracking interior point technique for linear constrained optimization.By performing the QR decomposition of an affine scaling equality constraint matrix,the conducted subproblem in the algorithm is changed into the general trust-region subproblem defined by minimizing a quadratic function subject only to an ellipsoidal constraint.By using both the trust-region strategy and the line-search technique,each iteration switches to a backtracking interior point step generated by the trustregion subproblem.The global convergence and fast local convergence rates for the proposed algorithm are established under some reasonable assumptions.A nonmonotonic criterion is used to speed up the convergence in some ill-conditioned cases.
Jianjun Qi; Bo Guo; Hongtao Lei; Tao Zhang
2014-01-01
This paper considers a project scheduling problem with the objective of minimizing resource availability costs appealed to finish al activities before the deadline. There are finish-start type precedence relations among the activities which require some kinds of renewable resources. We predigest the process of sol-ving the resource availability cost problem (RACP) by using start time of each activity to code the schedule. Then, a novel heuris-tic algorithm is proposed to make the process of looking for the best solution efficiently. And then pseudo particle swarm optimiza-tion (PPSO) combined with PSO and path relinking procedure is presented to solve the RACP. Final y, comparative computational experiments are designed and the computational results show that the proposed method is very effective to solve RACP.
Nourelfath, M.; Nahas, N.; Montreuil, B.
2007-12-01
This article uses a hybrid optimization approach to solve the discrete facility layout problem (FLP), modelled as a quadratic assignment problem (QAP). The idea of this approach design is inspired by the ant colony meta-heuristic optimization method, combined with the extended great deluge (EGD) local search technique. Comparative computational experiments are carried out on benchmarks taken from the QAP-library and from real life problems. The performance of the proposed algorithm is compared to construction and improvement heuristics such as H63, HC63-66, CRAFT and Bubble Search, as well as other existing meta-heuristics developed in the literature based on simulated annealing (SA), tabu search and genetic algorithms (GAs). This algorithm is compared also to other ant colony implementations for QAP. The experimental results show that the proposed ant colony optimization/extended great deluge (ACO/EGD) performs significantly better than the existing construction and improvement algorithms. The experimental results indicate also that the ACO/EGD heuristic methodology offers advantages over other algorithms based on meta-heuristics in terms of solution quality.
Coupled Subcritical Water and Solid Phase Extraction for In-Situ Chemical Analysis Project
National Aeronautics and Space Administration — Leiden Measurement Technology (LMT) will design and develop a low volume analyte separation, concentration, and transfer system (ConTech), that couples a Subcritical...
Fiber Coupled Pulse Shaper for Sub-Nanosecond Pulse Lidar Project
National Aeronautics and Space Administration — This Small Business Innovation Research Phase I effort will investigate the feasibility of using electro-optic (EO) beam scanning element to control coupling into a...
Coupled Viscous/Inviscid Analysis of Powered-Lift Airfoils and Wings Project
National Aeronautics and Space Administration — This proposal is in response to NASA SBIR Topic A2.08 in the area of "Variable Fidelity, Physics-Based Design/Analysis Tools". The development of a coupled...
National Aeronautics and Space Administration — The objective of the research proposed herein is to define the coupled (combined) effect of critical environments on the structural performance of composite overwrap...
Häger, Christian; Brännström, Fredrik; Alvarado, Alex; Agrell, Erik
2014-01-01
We study the design of spectrally efficient fiber-optical communication systems based on different spatially coupled (SC) forward error correction (FEC) schemes. In particular, we optimize the allocation of the coded bits from the FEC encoder to the modulation bits of the signal constellation. Two SC code classes are considered. The codes in the first class are protograph-based low-density parity-check (LDPC) codes which are decoded using iterative soft-decision decoding. The codes in the second class are generalized LDPC codes which are decoded using iterative hard-decision decoding. For both code classes, the bit allocation is optimized for the terminated and tailbiting SC cases based on a density evolution analysis. An optimized bit allocation can significantly improve the performance of tailbiting SC codes codes over the baseline sequential allocation, up to the point where they have a comparable gap to capacity as their terminated counterparts, at a lower FEC overhead. For the considered terminated SC co...
Yu Wang
2016-04-01
Full Text Available Multiple-factor analysis and optimization play a critical role in the the ability to maximizethe stimulated reservoir volume (SRV and the success of economic shale gas production. In this paper, taking the typical continental naturally fractured silty laminae shale in China as anexample, response surface methodology (RSM was employed to optimize multiple hydraulic fracturing parameters to maximize the stimulated area in combination with numerical modeling based on the coupled flow-stress-damage (FSD approach. This paper demonstrates hydraulic fracturing effectiveness by defining two indicesnamelythe stimulated reservoir area (SRA and stimulated silty laminae area (SLA. Seven uncertain parameters, such as laminae thickness, spacing, dip angle, cohesion, internal friction angle (IFA, in situ stress difference (SD, and an operational parameter-injection rate (IR with a reasonable range based on silty Laminae Shale, Southeastern Ordos Basin, are used to fit a response of SRA and SLA as the objective function, and finally identity the optimum design under the parameters based on simultaneously maximizingSRA and SLA. In addition, asensitivity analysis of the influential factors is conducted for SRA and SLA. The aim of the study is to improve the artificial ability to control the fracturing network by means of multi-parameteroptimization. This work promises to provide insights into the effective exploitation of unconventional shale gas reservoirs via optimization of the fracturing design for continental shale, Southeastern Ordos Basin, China.
Samuel Boudet
2014-01-01
Full Text Available Muscle artifacts constitute one of the major problems in electroencephalogram (EEG examinations, particularly for the diagnosis of epilepsy, where pathological rhythms occur within the same frequency bands as those of artifacts. This paper proposes to use the method dual adaptive filtering by optimal projection (DAFOP to automatically remove artifacts while preserving true cerebral signals. DAFOP is a two-step method. The first step consists in applying the common spatial pattern (CSP method to two frequency windows to identify the slowest components which will be considered as cerebral sources. The two frequency windows are defined by optimizing convolutional filters. The second step consists in using a regression method to reconstruct the signal independently within various frequency windows. This method was evaluated by two neurologists on a selection of 114 pages with muscle artifacts, from 20 clinical recordings of awake and sleeping adults, subject to pathological signals and epileptic seizures. A blind comparison was then conducted with the canonical correlation analysis (CCA method and conventional low-pass filtering at 30 Hz. The filtering rate was 84.3% for muscle artifacts with a 6.4% reduction of cerebral signals even for the fastest waves. DAFOP was found to be significantly more efficient than CCA and 30 Hz filters. The DAFOP method is fast and automatic and can be easily used in clinical EEG recordings.
Sawicki, Jean-Paul; Saint-Eve, Frédéric; Petit, Pierre; Aillerie, Michel
2017-02-01
This paper presents results of experiments aimed to verify a formula able to compute duty cycle in the case of pulse width modulation control for a DC-DC converter designed and realized in laboratory. This converter, called Magnetically Coupled Boost (MCB) is sized to step up only one photovoltaic module voltage to supply directly grid inverters. Duty cycle formula will be checked in a first time by identifying internal parameter, auto-transformer ratio, and in a second time by checking stability of operating point on the side of photovoltaic module. Thinking on nature of generator source and load connected to converter leads to imagine additional experiments to decide if auto-transformer ratio parameter could be used with fixed value or on the contrary with adaptive value. Effects of load variations on converter behavior or impact of possible shading on photovoltaic module are also mentioned, with aim to design robust control laws, in the case of parallel association, designed to compensate unwanted effects due to output voltage coupling.
WEI Ke; BAO Qing
2012-01-01
Responses of the East Asian winter monsoon (EAWM) in future projections were studied based on two core future projections of CMIP5 in coordinated experiments with the IAP-coupled model FGOALS2-s.The projected changes of EAWM in climatology,seasonality,and interannual variability are reported here;the projections indicated strong warming in winter season.Warming increased with latitude,ranging from 1℃ to 3℃ in the Representative Concentration Pathways simulation RCP4.5 projection (an experiment that results in additional radiative forcing of ～4.5 W m-2 in 2100) and from 4℃ to 9℃ in the RCP8.5 projection (an experiment that results in additional radiative forcing of ～8.5 W m-2 in 2100).The northerly wind along the East Asian coastal region became stronger in both scenarios,indicating a stronger EAWM.Accordingly,interannual variability (described by the standard deviation of temperature) increased around the South China Sea and lower latitudes and decreased over eastern China,especially in North China.The two EAWM basic modes,defined by the temperature EOF analysis over East Asia,were associated with the Arctic Oscillation (AO) and stratospheric polar vortex.The future projections revealed more total variance attributable to the secondary mode,suggesting additional influences from the stratosphere.The correlation between AO and the leading mode decreased,while the correlation between AO and the secondary mode increased,implying increased complexity regarding the predictability of EAWM interannual variations in future projections.
Delahaye, P., E-mail: delahaye@ganil.fr; Jardin, P.; Maunoury, L. [GANIL, CEA/DSM-CNRS/IN2P3, Blvd. Becquerel, BP 55027, 14076 Caen Cedex 05 (France); Galatà, A.; Patti, G. [INFN–Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (Padova) (Italy); Angot, J.; Lamy, T.; Thuillier, T. [LPSC–Université Grenoble Alpes–CNRS/IN2P3, 53 rue des Martyrs, 38026 Grenoble Cedex (France); Cam, J. F.; Traykov, E.; Ban, G. [LPC Caen, 6 Blvd. Maréchal Juin, 14050 Caen Cedex (France); Celona, L. [INFN–Laboratori Nazionali del Sud, via S. Sofia 62, 95125 Catania (Italy); Choinski, J.; Gmaj, P. [Heavy Ion Laboratory, University of Warsaw, ul. Pasteura 5a, 02 093 Warsaw (Poland); Koivisto, H.; Kolhinen, V.; Tarvainen, O. [Department of Physics, University of Jyväskylä, PB 35 (YFL), 40351 Jyväskylä (Finland); Vondrasek, R. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439 (United States); Wenander, F. [ISOLDE, CERN, 1211 Geneva 23 (Switzerland)
2016-02-15
The present paper summarizes the results obtained from the past few years in the framework of the Enhanced Multi-Ionization of short-Lived Isotopes for Eurisol (EMILIE) project. The EMILIE project aims at improving the charge breeding techniques with both Electron Cyclotron Resonance Ion Sources (ECRIS) and Electron Beam Ion Sources (EBISs) for European Radioactive Ion Beam (RIB) facilities. Within EMILIE, an original technique for debunching the beam from EBIS charge breeders is being developed, for making an optimal use of the capabilities of CW post-accelerators of the future facilities. Such a debunching technique should eventually resolve duty cycle and time structure issues which presently complicate the data-acquisition of experiments. The results of the first tests of this technique are reported here. In comparison with charge breeding with an EBIS, the ECRIS technique had lower performance in efficiency and attainable charge state for metallic ion beams and also suffered from issues related to beam contamination. In recent years, improvements have been made which significantly reduce the differences between the two techniques, making ECRIS charge breeding more attractive especially for CW machines producing intense beams. Upgraded versions of the Phoenix charge breeder, originally developed by LPSC, will be used at SPES and GANIL/SPIRAL. These two charge breeders have benefited from studies undertaken within EMILIE, which are also briefly summarized here.
Coupled stochastic soil moisture simulation-optimization model of deficit irrigation
Alizadeh, Hosein; Mousavi, S. Jamshid
2013-07-01
This study presents an explicit stochastic optimization-simulation model of short-term deficit irrigation management for large-scale irrigation districts. The model which is a nonlinear nonconvex program with an economic objective function is built on an agrohydrological simulation component. The simulation component integrates (1) an explicit stochastic model of soil moisture dynamics of the crop-root zone considering interaction of stochastic rainfall and irrigation with shallow water table effects, (2) a conceptual root zone salt balance model, and 3) the FAO crop yield model. Particle Swarm Optimization algorithm, linked to the simulation component, solves the resulting nonconvex program with a significantly better computational performance compared to a Monte Carlo-based implicit stochastic optimization model. The model has been tested first by applying it in single-crop irrigation problems through which the effects of the severity of water deficit on the objective function (net benefit), root-zone water balance, and irrigation water needs have been assessed. Then, the model has been applied in Dasht-e-Abbas and Ein-khosh Fakkeh Irrigation Districts (DAID and EFID) of the Karkheh Basin in southwest of Iran. While the maximum net benefit has been obtained for a stress-avoidance (SA) irrigation policy, the highest water profitability has been resulted when only about 60% of the water used in the SA policy is applied. The DAID with respectively 33% of total cultivated area and 37% of total applied water has produced only 14% of the total net benefit due to low-valued crops and adverse soil and shallow water table conditions.
Jones, Chris D.; Arora, Vivek; Friedlingstein, Pierre; Bopp, Laurent; Brovkin, Victor; Dunne, John; Graven, Heather; Hoffman, Forrest; Ilyina, Tatiana; John, Jasmin G.; Jung, Martin; Kawamiya, Michio; Koven, Charlie; Pongratz, Julia; Raddatz, Thomas; Randerson, James T.; Zaehle, Sönke
2016-08-01
Coordinated experimental design and implementation has become a cornerstone of global climate modelling. Model Intercomparison Projects (MIPs) enable systematic and robust analysis of results across many models, by reducing the influence of ad hoc differences in model set-up or experimental boundary conditions. As it enters its 6th phase, the Coupled Model Intercomparison Project (CMIP6) has grown significantly in scope with the design and documentation of individual simulations delegated to individual climate science communities. The Coupled Climate-Carbon Cycle Model Intercomparison Project (C4MIP) takes responsibility for design, documentation, and analysis of carbon cycle feedbacks and interactions in climate simulations. These feedbacks are potentially large and play a leading-order contribution in determining the atmospheric composition in response to human emissions of CO2 and in the setting of emissions targets to stabilize climate or avoid dangerous climate change. For over a decade, C4MIP has coordinated coupled climate-carbon cycle simulations, and in this paper we describe the C4MIP simulations that will be formally part of CMIP6. While the climate-carbon cycle community has created this experimental design, the simulations also fit within the wider CMIP activity, conform to some common standards including documentation and diagnostic requests, and are designed to complement the CMIP core experiments known as the Diagnostic, Evaluation and Characterization of Klima (DECK). C4MIP has three key strands of scientific motivation and the requested simulations are designed to satisfy their needs: (1) pre-industrial and historical simulations (formally part of the common set of CMIP6 experiments) to enable model evaluation, (2) idealized coupled and partially coupled simulations with 1 % per year increases in CO2 to enable diagnosis of feedback strength and its components, (3) future scenario simulations to project how the Earth system will respond to
Jing, L.; Stephansson, O. [Royal Inst. of Technology, Stockholm (Sweden). Engineering Geology; Tsang, C.F. [Lawrence Berkely National Laboratory, Berkeley, CA (United States). Earth Science Div.; Mayor, J.C. [ENRESA, Madrid (Spain); Kautzky, F. [Swedish Nuclear Power Inspectorate, Stockholm (Sweden)] (eds.)
2005-02-15
DECOVALEX is an international consortium of governmental agencies associated with the disposal of high-level nuclear waste in a number of countries. The consortium's mission is the DEvelopment of COupled models and their VALidation against EXperiments. Hence the acronym/name DECOVALEX. Currently, agencies from Canada, Finland, France, Germany, Japan, Spain, Switzerland, Sweden, United Kingdom, and the United States are in DECOVALEX. Emplacement of nuclear waste in a repository in geologic media causes a number of physical processes to be intensified in the surrounding rock mass due to the decay heat from the waste. The four main processes of concern are thermal, hydrological, mechanical and chemical. Interactions or coupling between these heat-driven processes must be taken into account in modeling the performance of the repository for such modeling to be meaningful and reliable. DECOVALEX III is organized around four tasks. The FEBEX (Full-scale Engineered Barriers EXperiment) in situ experiment being conducted at the Grimsel site in Switzerland is to be simulated and analyzed in Task 1. Task 2, centered around the Drift Scale Test (DST) at Yucca Mountain in Nevada, USA, has several sub-tasks (Task 2A, Task 2B, Task 2C and Task 2D) to investigate a number of the coupled processes in the DST. Task 3 studies three benchmark problems: a) the effects of thermal-hydrologic-mechanical (THM) coupling on the performance of the near-field of a nuclear waste repository (BMT1); b) the effect of upscaling THM processes on the results of performance assessment (BMT2); and c) the effect of glaciation on rock mass behavior (BMT3). Task 4 is on the direct application of THM coupled process modeling in the performance assessment of nuclear waste repositories in geologic media. This executive summary presents the motivation, structure, objectives, approaches, and the highlights of the main achievements and outstanding issues of the tasks studied in the DECOVALEX III project
Sheng, Ying; Zhang, Yufeng; Fang, Lei
2014-01-01
The high temperature heat pump and desiccant wheel (HTHP&DW) system can make full use of heat released from the condenser of heat pump for DW regeneration without additional heat. In this study, DW operation in the HTHP&DW system was investigated experimentally, and the optimization analysis....... Compared to the isosteric heat, heat accumulation in the desiccant and matrix material and heat leakage from regeneration side to process side have greater influence on the adiabatic effectiveness. Higher regeneration temperature leads to lower adiabatic effectiveness that increases more cooling load...
Kawamoto, Shigeru; Ikeda, Yuichi; Fukui, Chihiro; Tateshita, Fumihiko
Private finance initiative is a business scheme that materializes social infrastructure and public services by utilizing private-sector resources. In this paper we propose a new method to optimize capital structure, which is the ratio of capital to debt, and senior-sub structure, which is the ratio of senior loan to subordinated loan, for private finance initiative. We make the quantitative analysis of a private finance initiative's project using the proposed method. We analyze trade-off structure between risk and return in the project, and optimize capital structure and senior-sub structure. The method we propose helps to improve financial stability of the project, and to make a fund raising plan that is expected to be reasonable for project sponsor and moneylender.
The use of surrogates for an optimal management of coupled groundwater-agriculture hydrosystems
Grundmann, J.; Schütze, N.; Brettschneider, M.; Schmitz, G. H.; Lennartz, F.
2012-04-01
For ensuring an optimal sustainable water resources management in arid coastal environments, we develop a new simulation based integrated water management system. It aims at achieving best possible solutions for groundwater withdrawals for agricultural and municipal water use including saline water management together with a substantial increase of the water use efficiency in irrigated agriculture. To achieve a robust and fast operation of the management system regarding water quality and water quantity we develop appropriate surrogate models by combining physically based process modelling with methods of artificial intelligence. Thereby we use an artificial neural network for modelling the aquifer response, inclusive the seawater interface, which was trained on a scenario database generated by a numerical density depended groundwater flow model. For simulating the behaviour of high productive agricultural farms crop water production functions are generated by means of soil-vegetation-atmosphere-transport (SVAT)-models, adapted to the regional climate conditions, and a novel evolutionary optimisation algorithm for optimal irrigation scheduling and control. We apply both surrogates exemplarily within a simulation based optimisation environment using the characteristics of the south Batinah region in the Sultanate of Oman which is affected by saltwater intrusion into the coastal aquifer due to excessive groundwater withdrawal for irrigated agriculture. We demonstrate the effectiveness of our methodology for the evaluation and optimisation of different irrigation practices, cropping pattern and resulting abstraction scenarios. Due to contradicting objectives like profit-oriented agriculture vs. aquifer sustainability a multi-criterial optimisation is performed.
Sensitivity Analyses for Cross-Coupled Parameters in Automotive Powertrain Optimization
Pongpun Othaganont
2014-06-01
Full Text Available When vehicle manufacturers are developing new hybrid and electric vehicles, modeling and simulation are frequently used to predict the performance of the new vehicles from an early stage in the product lifecycle. Typically, models are used to predict the range, performance and energy consumption of their future planned production vehicle; they also allow the designer to optimize a vehicle’s configuration. Another use for the models is in performing sensitivity analysis, which helps us understand which parameters have the most influence on model predictions and real-world behaviors. There are various techniques for sensitivity analysis, some are numerical, but the greatest insights are obtained analytically with sensitivity defined in terms of partial derivatives. Existing methods in the literature give us a useful, quantified measure of parameter sensitivity, a first-order effect, but they do not consider second-order effects. Second-order effects could give us additional insights: for example, a first order analysis might tell us that a limiting factor is the efficiency of the vehicle’s prime-mover; our new second order analysis will tell us how quickly the efficiency of the powertrain will become of greater significance. In this paper, we develop a method based on formal optimization mathematics for rapid second-order sensitivity analyses and illustrate these through a case study on a C-segment electric vehicle.
Zhao, Chao; Cao, Zhibo; Fraser, John; Oztekin, Alparslan; Cheng, Xuanhong
2017-01-01
Enriching nanoparticles in an aqueous solution is commonly practiced for various applications. Despite recent advances in microfluidic technologies, a general method to concentrate nanoparticles in a microfluidic channel in a label free and continuous flow fashion is not yet available, due to strong Brownian motion on the nanoscale. Recent research of thermophoresis indicates that thermophoretic force can overcome the Brownian force to direct nanoparticle movement. Coupling thermophoresis with natural convection on the microscale has been shown to induce significant enrichment of biomolecules in a thermal diffusion column. However, the column operates in a batch process, and the concentrated samples are inconvenient to retrieve. We have recently designed a microfluidic device that combines a helical fluid motion and simple one-dimensional temperature gradient to achieve effective nanoparticle focusing in a continuous flow. The helical convection is introduced by microgrooves patterned on the channel floor, which directly controls the focusing speed and power. Here, COMSOL simulations are conducted to study how the device geometry and flow rate influence transport and subsequent nanoparticle focusing, with a constant temperature gradient. The results demonstrate a complex dependence of nanoparticle accumulation on the microgroove tilting angle, depth, and spacing, as well as channel width and flow rate. Further dimensional analyses reveal that the ratio between particle velocities induced by thermophoretic and fluid inertial forces governs the particle concentration factor, with a maximum concentration at a ratio of approximately one. This simple relationship provides fundamental insights about nanoparticle transport in coupled flow and thermal fields. The study also offers a useful guideline to the design and operation of nanoparticle concentrators based on combining engineered helical fluid motion subject to phoretic fields.
An optimal preconditioner for models of coupled magma/mantle dynamics
Rhebergen, Sander; Katz, Richard F; Wathen, Andrew J
2013-01-01
This article considers the iterative solution of a finite element discretisation of magma dynamics equations. In simplified form, the magma dynamics equations share some features of the Stokes equations. We therefore formulate, analyse and numerically test a Elman, Silvester and Wathen-type block preconditioner for magma dynamics. We prove analytically, and demonstrate numerically, optimality of the preconditioner. The presented analysis highlights the dependence of the preconditioner on parameters in the magma dynamics equations that can affect convergence of iterative linear solvers. The analysis is verified through a range of two- and three-dimensional numerical examples on unstructured grids, from simple illustrate problems through to large problems on subduction zone-like geometries. The computer code to reproduce all numerical examples is freely available as supporting material.
Computational Tool for Coupled Simulation of Nonequilibrium Hypersonic Flows with Ablation Project
National Aeronautics and Space Administration — The goal of this SBIR project is to develop a computational tool with unique predictive capabilities for the aerothermodynamic environment around ablation-cooled...
Computational Tool for Coupled Simulation of Nonequilibrium Hypersonic Flows with Ablation Project
National Aeronautics and Space Administration — The goal of this SBIR project is to develop a predictive computational tool for the aerothermal environment around ablation-cooled hypersonic atmospheric entry...
Nikitin, Alexander P.; Bulsara, Adi R.; Stocks, Nigel G.
2017-03-01
Inspired by recent results on self-tunability in the outer hair cells of the mammalian cochlea, we describe an array of magnetic sensors where each individual sensor can self-tune to an optimal operating regime. The self-tuning gives the array its "biomimetic" features. We show that the overall performance of the array can, as expected, be improved by increasing the number of sensors but, however, coupling between sensors reduces the overall performance even though the individual sensors in the system could see an improvement. We quantify the similarity of this phenomenon to the Ringelmann effect that was formulated 103 years ago to account for productivity losses in human and animal groups. We propose a global feedback scheme that can be used to greatly mitigate the performance degradation that would, normally, stem from the Ringelmann effect.
Mani, Karthik
mathematically establishing a clear relationship between the functional of interest and the regions of the computational mesh that are most relevant to it. The current work extends the use of adjoint methods to multiple governing disciplines that are tightly coupled, and more importantly unsteady in nature. The adjoint method is derived in a very general form for the purpose of computing the gradient vector for use in shape optimization in the context of coupled multidisciplinary unsteady equations. It is shown that computing the gradient vector in unsteady problems involves solving the analysis problem forward in time and then solving the adjoint problem backward in time. While adjoint methods have been used successively to drive spatial mesh adaptation, the current work extends the use of the computed unsteady adjoint variables for estimating temporal discretization error, which is then applied to temporal mesh adaptation. Additionally, the computed adjoint variables are also used for the estimation of algebraic error in the solution arising due to intentional or nonintentional partial convergence of the governing equations. Results indicate that the adaptation of the temporal resolution and convergence tolerance limits using adjoint-based error estimates is able to outperform traditional adaptation methods such as uniform refinement and those based on local error estimates. All of the development is carried out in a fully unstructured mesh framework with dynamic deformation of the computational spatial mesh.
Jin, Xiaoyan; Mok, Eun Kyung; Baek, Ji-Won [Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Park, Sang-Hyun [Smithers-Oasis Korea, 196-4 YongJungDoHa-Gil 157, Cheonan, Chungnum-Do (Korea, Republic of); Hwang, Seong-Ju, E-mail: hwangsju@ewha.ac.kr [Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 120-750 (Korea, Republic of)
2015-10-15
The electronic coupling and photocatalytic activity of Ag{sub 2}CO{sub 3}–TiO{sub 2} nanocomposite can be optimized by the fine-tuning of the band position of titanium oxide with nitrogen doping. The increase of the valence band energy of TiO{sub 2} by N-doping leads not only to the enhanced absorption of visible light but also to the promoted hole transfer from Ag{sub 2}CO{sub 3} to TiO{sub 2}, resulting in the efficient spatial separation of photogenerated electrons and holes. While the undoped Ag{sub 2}CO{sub 3}–TiO{sub 2} nanocomposite shows an inferior photocatalytic activity to the pure Ag{sub 2}CO{sub 3}, the photocatalyst performance of N-doped nanocomposite is better than those of Ag{sub 2}CO{sub 3} and undoped Ag{sub 2}CO{sub 3}–TiO{sub 2} nanocomposite. This observation underscores a significant enhancement of the photocatalytic activity of nanocomposite upon N-doping, a result of enhanced electronic coupling between the hybridized species. The present results clearly demonstrate the importance of the fine-tuning of band position in optimizing the photocatalytic activity of hybrid-type photocatalysts. - Highlights: • The band position of Ag{sub 2}CO{sub 3}–TiO{sub 2} can be effectively tailored by nitrogen doping. • The N-doping leads to the improvement of charge separation. • The N-doped Ag{sub 2}CO{sub 3}–TiO{sub 2} shows high photocatalytic activity.
All-at-once Optimization for Coupled Matrix and Tensor Factorizations
Acar, Evrim; Dunlavy, Daniel M
2011-01-01
Joint analysis of data from multiple sources has the potential to improve our understanding of the underlying structures in complex data sets. For instance, in restaurant recommendation systems, recommendations can be based on rating histories of customers. In addition to rating histories, customers' social networks (e.g., Facebook friendships) and restaurant categories information (e.g., Thai or Italian) can also be used to make better recommendations. The task of fusing data, however, is challenging since data sets can be incomplete and heterogeneous, i.e., data consist of both matrices, e.g., the person by person social network matrix or the restaurant by category matrix, and higher-order tensors, e.g., the "ratings" tensor of the form restaurant by meal by person. In this paper, we are particularly interested in fusing data sets with the goal of capturing their underlying latent structures. We formulate this problem as a coupled matrix and tensor factorization (CMTF) problem where heterogeneous data sets ...
Sun, Enwei; Sang, Shijing; Yuan, Zhongyuan; Qi, Xudong; Zhang, Rui; Cao, Wenwu
2015-01-01
The electrooptic and piezoelectric coupling effects in tetragonal relaxor-based ferroelectric 0.62Pb(Mg1/3Nb2/3)O3-0.38PbTiO3 (PMN-0.38PT) and 0.88Pb(Zn1/3Nb2/3)O3-0.12PbTiO3 (PZN-0.12PT) single-domain crystals have been analyzed by the coordinate transformation. The orientation dependence of the electrooptic and half-wave voltage was calculated based on the full sets of refractive indices, electrooptic and piezoelectric coefficients. The optimum orientation cuts for achieving the best electrooptic coefficient and half-wave voltage were found. The lowset half-wave voltage is only 76 V for the PMN-0.38PT single-domain crystal. Compared to commonly used electrooptic crystal LiNbO3, tetragonal relaxor-PT ferroelectric single-domain crystals are much superior for optical modulation applications because of their much higher linear electrooptic coefficients and substantially lower half-wave voltages when the piezoelectric strain influence is considered. PMID:25954059
Optimization for the structure of BF hearth bottom and the arrangement of thermal couples
Hongbo Zhao; Shusen Cheng
2006-01-01
The hearth of "heat transfer method" and the ceramic cup synthetic hearth bottom of "heart isolation method" are two most popular designs for blast furnace (BF). Although there are successful real examples, some disadvantages, for instance large heat loss and high cost, still exist for these designs. According to the theory of heat transfer, based on the calculation of temperature distribution of the hearth bottom, it is elucidated that all brick layers at the hearth bottom may not be considered as the only reason why different structures exhibited different temperature distributions although total heat resistance is the same, and then based on the effect of hot metal and cold water on different temperature distribution ranges, the concepts of "heat resistance" and "cooling enhancement" are put forth. Based on this, the disadvantages and the factors affecting temperature distribution, of the two types of hearth bottoms were illustrated. On the basis of these analyses, a novel structure for BF hearth bottom designing that can easily form "self-protecting" slag layer stably, called "the method of gradient brick layout that has an optimum combination of cooling enhancement and heat resistance"was proposed; it can not only prolong the hearth bottom longevity but also reduce the cost and heat loss. Also, the optimum arrangement of thermal couples in hearth bottom was suggested based on the previous studies on erosion prediction carried out by the author.
Optimizing Peri-URban Ecosystems (PURE) to re-couple urban-rural symbiosis.
Zhu, Yong-Guan; Reid, Brian J; Meharg, Andrew A; Banwart, Steve A; Fu, Bo-Jie
2017-05-15
Globally, rapid urbanization, along with economic development, is dramatically changing the balance of biogeochemical cycles, impacting upon ecosystem services and impinging on United Nation global sustainability goals (inter alia: sustainable cities and communities; responsible consumption and production; good health and well-being; clean water and sanitation, and; to protect and conserve life on land and below water). A key feature of the urban ecosystems is that nutrient stocks, carbon (C), nitrogen (N) and phosphorus (P), are being enriched. Furthermore, urban ecosystems are highly engineered, biogeochemical cycling of nutrients within urban ecosystems is spatially segregated, and nutrients exported (e.g. in food) from rural/peri-urban areas are not being returned to support primary production in these environments. To redress these imbalances we propose the concept of the Peri-URban Ecosystem (PURE). Through the merging of conceptual approaches that relate to Critical Zone science and the dynamics of successional climax PURE serves at the symbiotic interface between rural/natural and urban ecosystems and allow re-coupling of resource flows. PURE provides a framework for tackling the most pressing of societal challenges and supporting global sustainability goals. Copyright © 2017 Elsevier B.V. All rights reserved.
Reitz, Rolf; Foster, D.; Ghandhi, J.; Rothamer, D.; Rutland, C.; Sanders, S.; Trujillo, M.
2012-10-26
The goal of the present technology development was to increase the efficiency of internal combustion engines while minimizing the energy penalty of meeting emissions regulations. This objective was achieved through experimentation and the development of advanced combustion regimes and emission control strategies, coupled with advanced petroleum and non-petroleum fuel formulations. To meet the goals of the project, it was necessary to improve the efficiency of expansion work extraction, and this required optimized combustion phasing and minimized in-cylinder heat transfer losses. To minimize fuel used for diesel particulate filter (DPF) regeneration, soot emissions were also minimized. Because of the complex nature of optimizing production engines for real-world variations in fuels, temperatures and pressures, the project applied high-fidelity computing and high-resolution engine experiments synergistically to create and apply advanced tools (i.e., fast, accurate predictive models) developed for low-emission, fuel-efficient engine designs. The companion experiments were conducted using representative single- and multi-cylinder automotive and truck diesel engines.
Security Enhancement With Optimal QOS Using EAP-AKA In Hybrid Coupled 3G-WLAN Convergence Network
Shankar, R; Dananjayan, P; 10.5121/iju.2010.1303
2010-01-01
The third generation partnership project (3GPP) has addressed the feasibility of interworking and specified the interworking architecture and security architecture for third generation (3G)-wireless local area network (WLAN), it is developing, system architecture evolution (SAE)/ long term evolution (LTE) architecture, for the next generation mobile communication system. To provide a secure 3G-WLAN interworking in the SAE/LTE architecture, Extensible authentication protocol-authentication and key agreement (EAP-AKA) is used. However, EAP-AKA have several vulnerabilities. Therefore, this paper not only analyses the threats and attacks in 3G-WLAN interworking but also proposes a new authentication and key agreement protocol based on EAP-AKA. The proposed protocol combines elliptic curve Diffie-Hellman (ECDH) with symmetric key cryptosystem to overcome the vulnerabilities. The proposed protocol is used in hybrid coupled 3G-WLAN convergence network to analyse its efficiency in terms of QoS metrics, the results ob...
Ajayi, Folusho Francis; Kim, Kyoung-Yeol; Chae, Kyu-Jung; Choi, Mi-Jin; Chang, In Seop; Kim, In S
2010-03-01
Bio-hydrogen production in light-assisted microbial electrolysis cell (MEC) with a dye sensitized solar cell (DSSC) was optimized by connecting multiple MECs to a single dye (N719) sensitized solar cell (V(OC) approx. 0.7 V). Hydrogen production occurred simultaneously in all the connected MECs when the solar cell was irradiated with light. The amount of hydrogen produced in each MEC depends on the activity of the microbial catalyst on their anode. Substrate (acetate) to hydrogen conversion efficiencies ranging from 42% to 65% were obtained from the reactors during the experiment. A moderate light intensity of 430 W m(-2) was sufficient for hydrogen production in the coupled MEC-DSSC. A higher light intensity of 915 W m(-2), as well as an increase in substrate concentration, did not show any improvement in the current density due to limitation caused by the rate of microbial oxidation on the anode. A significant reduction in the surface area of the connected DSSC only showed a slight effect on current density in the coupled MEC-DSSC system when irradiated with light.
Optimized assembly and covalent coupling of single-molecule DNA origami nanoarrays.
Gopinath, Ashwin; Rothemund, Paul W K
2014-12-23
Artificial DNA nanostructures, such as DNA origami, have great potential as templates for the bottom-up fabrication of both biological and nonbiological nanodevices at a resolution unachievable by conventional top-down approaches. However, because origami are synthesized in solution, origami-templated devices cannot easily be studied or integrated into larger on-chip architectures. Electrostatic self-assembly of origami onto lithographically defined binding sites on Si/SiO2 substrates has been achieved, but conditions for optimal assembly have not been characterized, and the method requires high Mg2+ concentrations at which most devices aggregate. We present a quantitative study of parameters affecting origami placement, reproducibly achieving single-origami binding at 94±4% of sites, with 90% of these origami having an orientation within ±10° of their target orientation. Further, we introduce two techniques for converting electrostatic DNA-surface bonds to covalent bonds, allowing origami arrays to be used under a wide variety of Mg2+-free solution conditions.
Rice, Anne M; Mahling, Ryan; Fealey, Michael E; Rannikko, Anika; Dunleavy, Katie; Hendrickson, Troy; Lohese, K Jean; Kruggel, Spencer; Heiling, Hillary; Harren, Daniel; Sutton, R Bryan; Pastor, John; Hinderliter, Anne
2014-09-01
Eukaryotic lipids in a bilayer are dominated by weak cooperative interactions. These interactions impart highly dynamic and pliable properties to the membrane. C2 domain-containing proteins in the membrane also interact weakly and cooperatively giving rise to a high degree of conformational plasticity. We propose that this feature of weak energetics and plasticity shared by lipids and C2 domain-containing proteins enhance a cell's ability to transduce information across the membrane. We explored this hypothesis using information theory to assess the information storage capacity of model and mast cell membranes, as well as differential scanning calorimetry, carboxyfluorescein release assays, and tryptophan fluorescence to assess protein and membrane stability. The distribution of lipids in mast cell membranes encoded 5.6-5.8bits of information. More information resided in the acyl chains than the head groups and in the inner leaflet of the plasma membrane than the outer leaflet. When the lipid composition and information content of model membranes were varied, the associated C2 domains underwent large changes in stability and denaturation profile. The C2 domain-containing proteins are therefore acutely sensitive to the composition and information content of their associated lipids. Together, these findings suggest that the maximum flow of signaling information through the membrane and into the cell is optimized by the cooperation of near-random distributions of membrane lipids and proteins. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova.
S, Kyriacou; E, Kontoleontos; S, Weissenberger; L, Mangani; E, Casartelli; I, Skouteropoulou; M, Gattringer; A, Gehrer; M, Buchmayr
2014-03-01
An efficient hydraulic optimization procedure, suitable for industrial use, requires an advanced optimization tool (EASY software), a fast solver (block coupled CFD) and a flexible geometry generation tool. EASY optimization software is a PCA-driven metamodel-assisted Evolutionary Algorithm (MAEA (PCA)) that can be used in both single- (SOO) and multiobjective optimization (MOO) problems. In MAEAs, low cost surrogate evaluation models are used to screen out non-promising individuals during the evolution and exclude them from the expensive, problem specific evaluation, here the solution of Navier-Stokes equations. For additional reduction of the optimization CPU cost, the PCA technique is used to identify dependences among the design variables and to exploit them in order to efficiently drive the application of the evolution operators. To further enhance the hydraulic optimization procedure, a very robust and fast Navier-Stokes solver has been developed. This incompressible CFD solver employs a pressure-based block-coupled approach, solving the governing equations simultaneously. This method, apart from being robust and fast, also provides a big gain in terms of computational cost. In order to optimize the geometry of hydraulic machines, an automatic geometry and mesh generation tool is necessary. The geometry generation tool used in this work is entirely based on b-spline curves and surfaces. In what follows, the components of the tool chain are outlined in some detail and the optimization results of hydraulic machine components are shown in order to demonstrate the performance of the presented optimization procedure.
Optimizing the control of foot-and-mouth disease in Denmark by simulation – the project outline
Enøe, Claes
2012-01-01
The primary objective of this project was to generate scientifically based methods for improving the control and eradication of foot-and-mouth disease (FMD). This was achieved by using and optimizing existing stochastic simulation models. These include the: 1) InterSpread Plus model from Massey...
Topology Optimization of Thermal Heat Sinks
Klaas Haertel, Jan Hendrik; Engelbrecht, Kurt; Lazarov, Boyan Stefanov
2015-01-01
In this paper, topology optimization is applied to optimize the cooling performance of thermal heat sinks. The coupled two-dimensional thermofluid model of a heat sink cooled with forced convection and a density-based topology optimization including density filtering and projection are implemented...... in COMSOL Multiphysics. The optimization objective is to minimize the heat sink’s temperature for a prescribed pressure drop and fixed heat generation. To conduct the optimization, COMSOL’s Optimization Module with GCMMA as the optimization method is used. The implementation of this topology optimization...
Bai Xiaoping
2012-09-01
Full Text Available The equipment investment scheme evaluation of enterprise is usually multi-objective optimization problem affected by many factors. Among many optimization methods, the common fuzzy matter element is based on the matter-element analysis and combined with the concepts of fuzzy mathematics, which can reflect the subjective fuzzy judgment; the common entropy weight method makes use of the judgment matrix composed of evaluation index value, Weights gotten by the common entropy weight method mainly reflects usefulness of data and can't reflect actual importance of evaluation indexes. Considering this fact, this study integrates engineering economics, reliability theory, fuzzy matter element and entropy theory presents a new optimization model about enterprise equipment investment project and also presents detailed methods and steps of application of integrated model in concrete example, which can offer the reference for project investment activity of practical enterprise equipment.
CO2 Separation Using Thermally Optimized Membranes: A Comprehensive Project Report (2000 - 2007)
N/A
2008-03-04
This is a complete (Fiscal Years 2000–2006) collection of the Idaho National Laboratory’s (INL) research and development contributions to the project, “CO2 Separation Using Thermally Optimized Membranes.” The INL scientific contribution to the project has varied due to the fluctuations in funding from year to year. The focus of the project was polybenzimidazole (PBI) membranes and developing PBI compounds (both substitution and blends) that provide good film formation and gas separation membranes. The underlying problem with PBI is its poor solubility in common solvents. Typically, PBI is dissolved in “aggressive” solvents, like N,N-dimethylacetamide (DMAc) and N methylpyrrolidone (NMP). The INL FY-03 research was directed toward making soluble N-substituted PBI polymers, where INL was very successful. Many different types of modified PBI polymers were synthesized; however, film formation proved to be a big problem with both unsubstituted and N-substituted PBIs. Therefore, INL researchers directed their attention to using plasticizers or additives to make the membranes more stable and workable. During the course of these studies, other high-performance polymers (like polyamides and polyimides) were found to be better materials, which could be used either by themselves or blends with PBI. These alternative high-performance polymers provided the best pathway forward for soluble high-temperature polymers with good stable film formation properties. At present, the VTEC polyimides (product of RBI, Inc.) are the best film formers that exhibit high-temperature resistance. INL’s gas testing results show VTEC polyimides have very good gas selectivities for both H2/CO2 and CO2/CH4. Overall, these high-performance polymers pointed towards new research areas where INL has gained a greater understanding of polymer film formation and gas separation. These studies are making possible a direct approach to stable polymer-based high-temperature gas separation membranes
CO2 Separation Using Thermally Optimized Membranes: A Comprehensive Project Report (2000 - 2007)
J.R. Klaehn; C.J. Orme; E.S. Peterson; T.A. Luther; M.G. Jones; A.K. Wertsching
2008-03-01
This is a complete (Fiscal Years 2000–2006) collection of the Idaho National Laboratory’s (INL) research and development contributions to the project, “CO2 Separation Using Thermally Optimized Membranes.” The INL scientific contribution to the project has varied due to the fluctuations in funding from year to year. The focus of the project was polybenzimidazole (PBI) membranes and developing PBI compounds (both substitution and blends) that provide good film formation and gas separation membranes. The underlying problem with PBI is its poor solubility in common solvents. Typically, PBI is dissolved in “aggressive” solvents, like N,N-dimethylacetamide (DMAc) and N methylpyrrolidone (NMP). The INL FY-03 research was directed toward making soluble N-substituted PBI polymers, where INL was very successful. Many different types of modified PBI polymers were synthesized; however, film formation proved to be a big problem with both unsubstituted and N-substituted PBIs. Therefore, INL researchers directed their attention to using plasticizers or additives to make the membranes more stable and workable. During the course of these studies, other high-performance polymers (like polyamides and polyimides) were found to be better materials, which could be used either by themselves or blends with PBI. These alternative high-performance polymers provided the best pathway forward for soluble high-temperature polymers with good stable film formation properties. At present, the VTEC polyimides (product of RBI, Inc.) are the best film formers that exhibit high-temperature resistance. INL’s gas testing results show VTEC polyimides have very good gas selectivities for both H2/CO2 and CO2/CH4. Overall, these high-performance polymers pointed towards new research areas where INL has gained a greater understanding of polymer film formation and gas separation. These studies are making possible a direct approach to stable polymer-based high-temperature gas separation membranes
Coupled BOUSS-2D and CMS-Wave Modeling Approach for Harbor Projects
2012-08-01
al. 2011; Demirbilek et al. 2007) is part of the Coastal Modeling System ( CMS ) for simulating combined waves, currents, sediment transport, and...III. 2011. Verification and Validation of the Coastal Modeling System : Report 2, CMS -Wave, Tech. Report ERDC/CHL-TR-11-10, U.S. Army Engineer R&D...ERDC/CHL CHETN-IV-84 August 2012 Approved for public release; distribution is unlimited. Coupled BOUSS-2D and CMS -Wave Modeling Approach for
Optimization of a Light Collection System for use in the Neutron Lifetime Project
Taylor, C.; O'Shaughnessy, C.; Mumm, P.; Thompson, A.; Huffman, P.
2007-10-01
The Ultracold Neutron (UCN) Lifetime Project is an ongoing experiment with the objective of improving the average measurement of the neutron beta-decay lifetime. A more accurate measurement may increase our understanding of the electroweak interaction and improve astrophysical/cosmological theories on Big Bang nucleosynthesis. The current apparatus uses 0.89 nm cold neutrons to produce UCN through inelastic collisions with superfluid 4He in the superthermal process. The lifetime of the UCN is measured by detection of scintillation light from superfluid 4He created by electrons produced in neutron decay. Competing criteria of high detection efficiency outside of the apparatus and minimum heating of the experimental cell has led to the design of an acrylic light collection system. Initial designs were based on previous generations of the apparatus. ANSYS was used to optimize the cooling system for the light guide by checking simulated end conditions based on width of contact area, number of contact points, and location on the guide itself. SolidWorks and AutoCAD were used for design. The current system is in the production process.
Project Luna Succendo: The Lunar Evolutionary Growth-Optimized (LEGO) Reactor
Bess, John Darrell
A final design has been established for a basic Lunar Evolutionary Growth-Optimized (LEGO) Reactor using current and near-term technologies. The LEGO Reactor is a modular, fast-fission, heatpipe-cooled, clustered-reactor system for lunar-surface power generation. The reactor is divided into subcritical units that can be safely launched within lunar shipments from the Earth, and then emplaced directly into holes drilled into the lunar regolith to form a critical reactor assembly. The regolith would not just provide radiation shielding, but serve as neutron-reflector material as well. The reactor subunits are to be manufactured using proven and tested materials for use in radiation environments, such as uranium-dioxide fuel, stainless-steel cladding and structural support, and liquid-sodium heatpipes. The LEGO Reactor system promotes reliability, safety, and ease of manufacture and testing at the cost of an increase in launch mass per overall rated power level and a reduction in neutron economy when compared to a single-reactor system. A single unshielded LEGO Reactor subunit has an estimated mass of approximately 448 kg and provides 5 kWe using a free-piston Stirling space converter. The overall envelope for a single unit with fully extended radiator panels has a height of 8.77 m and a diameter of 0.50 m. The subunits can be placed with centerline distances of approximately 0.6 m in a hexagonal-lattice pattern to provide sufficient neutronic coupling while allowing room for heat rejection and interstitial control. A lattice of six subunits could provide sufficient power generation throughout the initial stages of establishing a lunar outpost. Portions of the reactor may be neutronically decoupled to allow for reduced power production during unmanned periods of base operations. During later stages of lunar-base development, additional subunits may be emplaced and coupled into the existing LEGO Reactor network Future improvements include advances in reactor control
Carver, Charles S.; Scheier, Michael F.; Segerstrom, Suzanne C.
2010-01-01
Optimism is an individual difference variable that reflects the extent to which people hold generalized favorable expectancies for their future. Higher levels of optimism have been related prospectively to better subjective well-being in times of adversity or difficulty (i.e., controlling for previous well-being). Consistent with such findings, optimism has been linked to higher levels of engagement coping and lower levels of avoidance, or disengagement, coping. There is evidence that optimism is associated with taking proactive steps to protect one's health, whereas pessimism is associated with health-damaging behaviors. Consistent with such findings, optimism is also related to indicators of better physical health. The energetic, task-focused approach that optimists take to goals also relates to benefits in the socioeconomic world. Some evidence suggests that optimism relates to more persistence in educational efforts and to higher later income. Optimists also appear to fare better than pessimists in relationships. Although there are instances in which optimism fails to convey an advantage, and instances in which it may convey a disadvantage, those instances are relatively rare. In sum, the behavioral patterns of optimists appear to provide models of living for others to learn from. PMID:20170998
Auclair, K. D.
2002-02-25
This paper describes the ongoing integrated life-cycle optimization efforts to achieve both design flexibility and design stability for activities associated with the Waste Treatment Plant at Hanford. Design flexibility is required to support the Department of Energy Office of River Protection Balance of Mission objectives, and design stability to meet the Waste Treatment Plant construction and commissioning requirements in order to produce first glass in 2007. The Waste Treatment Plant is a large complex project that is driven by both technology and contractual requirements. It is also part of a larger overall mission, as a component of the River Protection Project, which is driven by programmatic requirements and regulatory, legal, and fiscal constraints. These issues are further complicated by the fact that both of the major contractors involved have a different contract type with DOE, and neither has a contract with the other. This combination of technical and programmatic drivers, constraints, and requirements will continue to provide challenges and opportunities for improvement and optimization. The Bechtel National, Inc. team is under contract to engineer, procure, construct, commission and test the Waste Treatment Plant on or ahead of schedule, at or under cost, and with a throughput capacity equal to or better than specified. The Department of Energy is tasked with the long term mission of waste retrieval, treatment, and disposal. While each mission is a compliment and inextricably linked to one another, they are also at opposite ends of the spectrum, in terms of expectations of one another. These mission requirements, that are seemingly in opposition to one another, pose the single largest challenge and opportunity for optimization: one of balance. While it is recognized that design maturation and optimization are the normal responsibility of any engineering firm responsible for any given project, the aspects of integrating requirements and the management
2013-09-01
guide to the project management body of knowledge ( PMBOK (R) GUIDE). Newtown Square, PA: Project Management Institute, Inc. Ulrich, K., & Eppinger, S...activities to meet the project requirements. (Project Management Institute, Inc., 2013, p. 6) The PMBOK states that project management requires a set of...The PMBOK , however, does not address the product processes (i.e., processes required to ensure the project’s deliverable meets the customer’s needs
Computation of Yukawa couplings for Calabi-Yau hypersurfaces in weighted projective spaces
Kanter, Yu
1994-01-01
Greene, Morrison and Plesser \\cite{GMP} have recently suggested a general method for constructing a mirror map between a d-dimensional Calabi-Yau hypersurface and its mirror partner for d > 3. We apply their method to smooth hypersurfaces in weighted projective spaces and compute the Chern numbers of holomorphic curves on these hypersurfaces. As anticipated, the results satisfy nontrivial integrality constraints. These examples differ from those studied previously in that standard methods of algebraic geometry which work in the ordinary projective space case for low degree curves are not generally applicable. In the limited special cases in which they do work we can get independent predictions, and we find agreement with our results.
Pearce, Charles
2009-01-01
Focuses on mathematical structure, and on real-world applications. This book includes developments in several optimization-related topics such as decision theory, linear programming, turnpike theory, duality theory, convex analysis, and queuing theory.
Optimal reliability allocation for large software projects through soft computing techniques
Madsen, Henrik; Albeanu, Grigore; Albu, Razvan-Daniel
2012-01-01
or maximizing the system reliability subject to budget constraints. These kinds of optimization problems were considered both in deterministic and stochastic frameworks in literature. Recently, the intuitionistic-fuzzy optimization approach was considered as a soft computing successful modelling approach....... Firstly, a review on existing soft computing approaches to optimization is given. The main section extends the results considering self-organizing migrating algorithms for solving intuitionistic-fuzzy optimization problems attached to complex fault-tolerant software architectures which proved...
Hu, Xiexiaomen; Tutuncu, Azra; Eustes, Alfred; Augustine, Chad
2017-05-01
Enhanced Geothermal Systems (EGS) could potentially use technological advancements in coupled implementation of horizontal drilling and multistage hydraulic fracturing techniques in tight oil and shale gas reservoirs along with improvements in reservoir simulation techniques to design and create EGS reservoirs. In this study, a commercial hydraulic fracture simulation package, Mangrove by Schlumberger, was used in an EGS model with largely distributed pre-existing natural fractures to model fracture propagation during the creation of a complex fracture network. The main goal of this study is to investigate optimum treatment parameters in creating multiple large, planar fractures to hydraulically connect a horizontal injection well and a horizontal production well that are 10,000 ft. deep and spaced 500 ft. apart from each other. A matrix of simulations for this study was carried out to determine the influence of reservoir and treatment parameters on preventing (or aiding) the creation of large planar fractures. The reservoir parameters investigated during the matrix simulations include the in-situ stress state and properties of the natural fracture set such as the primary and secondary fracture orientation, average fracture length, and average fracture spacing. The treatment parameters investigated during the simulations were fluid viscosity, proppant concentration, pump rate, and pump volume. A final simulation with optimized design parameters was performed. The optimized design simulation indicated that high fluid viscosity, high proppant concentration, large pump volume and pump rate tend to minimize the complexity of the created fracture network. Additionally, a reservoir with 'friendly' formation characteristics such as large stress anisotropy, natural fractures set parallel to the maximum horizontal principal stress (SHmax), and large natural fracture spacing also promote the creation of large planar fractures while minimizing fracture complexity.
Dennis, M. L.; Armstrong, M. L.
2016-12-01
With the adoption of a new geometric datum in 2022, NOAA's National Geodetic Survey (NGS) will update the State Plane Coordinate System (SPCS). This update may consist simply of offsetting northings and/or eastings of existing SPCS projection zones. However, there is significant interest among NGS customers for another type of projected coordinate system: Low-Distortion Projections (LDPs). Although LDPs are presently not endorsed or supported by NGS, an assessment of LDP feasibility and performance is warranted within the context of updating the National Spatial Reference System (NSRS). LDPs are conformal map projections that minimize linear distortion at the topographic surface, manifested as a difference in distance between a pair of projected "grid" coordinates and the true horizontal "ground" distance. For SPCS, the differences can exceed a few hundred parts per million (ppm), and it can be problematic for engineering and surveying applications. Although such distortion cannot be eliminated, an LDP design method is presented that yields optimal results even for large areas of variable elevation. This approach can provide much lower distortion than the traditional method of scaling SPCS to ground, often called "modified" SPCS (MSPCS). MSPCS was included in training provided by NGS beginning in the 1960s, but it does not optimally minimize linear distortion. LDP systems have been adopted throughout the United States. One such system is the Oregon Coordinate Reference System (OCRS). Figure 1 compares distortion of an MSPCS for Bend, Oregon, to the OCRS zone for that area, where the green shading indicates distortion within ±20 ppm (2 cm/km or 0.1 ft/mile). The difference in performance is striking, even though both use the same projection type. Because LDPs cover larger areas, one can be used for many projects, whereas in most cases one MSPCS (and sometimes more) must be defined for every project. Importantly, the presented method for designing LDPs is based on
Keefer, Laurie; Doerfler, Bethany; Artz, Caroline
2012-02-01
Psychotherapy for Crohn's disease (CD) has focused on patients with psychological distress. Another approach to optimize management of CD is to target patients who do not exhibit psychological distress but engage in behaviors that undermine treatment efficacy / increase risk for flare. We sought to determine the feasibility/acceptability and estimate the effects of a program framed around Project Management (PM) principles on CD outcomes. Twenty-eight adults with quiescent CD without a history of psychiatric disorder were randomized to PM (n = 16) or treatment as usual (TAU; n = 12). Baseline and follow-up measures were Inflammatory Bowel Disease Questionnaire (IBDQ), Medication Adherence Scale (MAS), Perceived Stress Questionnaire (PSQ), and IBD Self-Efficacy Scale (IBD-SES). There were significant group × time effects favoring PM on IBDQ-Total Score (F(1) = 15.2, P = 0.001), IBDQ-Bowel (F(1) = 6.5, P = 0.02), and IBDQ-Systemic (F(1) = 9.3, P = 0.007) but not IBDQ-Emotional (F(1) = 1.9, P = ns) or IBDQ-Social (F(1) = 2.4, P = ns). There was a significant interaction effect favoring PM with respect to PSQ (F(1) = 8.4, P = 0.01) and IBD-SES (F(1) = 12.2, P = 0.003). There was no immediate change in MAS (F(1) = 4.3, P = ns). Moderate effect sizes (d > 0.30) were observed for IBDQ total score (d = 0.45), IBDQ bowel health (d = 0.45), and systemic health (d = 0.37). Effect sizes for PSQ (d = 0.13) and IBDSES (d = 0.17) were smaller. Behavioral programs that appeal to patients who may not seek psychotherapy for negative health behaviors may improve quality of life and potentially disease course and outcomes. Copyright © 2011 Crohn's & Colitis Foundation of America, Inc.
Dezhi Li
2016-04-01
Full Text Available In recent years, Chinese governments have launched ambitious plans in developing public rental housing (PRH, which are almost impossible to accomplish without the involvement of the private sector. Yet, very few quantitative studies have been carried out to evaluate the financial sustainability of PRH projects in China, especially from the perspective of the private sector. This knowledge gap is bridged through the evaluation of the financial sustainability of a hypothetical privately owned PRH project in Nanjing, China as a case study, utilizing data of a state-owned PRH project and the classic discounted cash flow method. The results indicate that the studied project is financially infeasible, which means that private companies would not be willing to participate in the provision of public rental housing, if they merely focus on profits. Then, the most cost-effective optimization measure of the studied case is quantitatively selected from four possible optimization scenarios, leading to a financial balance. This paper presents the current financial status of Chinese PRH projects, thereby providing policy makers with useful references to effectively accelerate the private sector’s provision of PRH in China.
Coupling interaction between biodiversity and aquatic habitat area in Western Route Project vicinity
Shi-min TIAN; Zhao-yin WANG; Xiang-jun LIU; Shi-kui LIANG
2010-01-01
The Western Route of the South-to-North Water Transfer Project will divert water from the upper Yangtze River and its tributaries,the Dadu River and Yalong River,to the upper Yellow River.The project may ease the water shortage in the Yellow River Basin.However,it may also have some effects on the ecosystem in the upper Yangtze River Basin.Benthic invertebrates play an important role in the river ecosystem,particularly in the circulation of materials and nutrition.Benthic invertebrates are widely used to quickly assess river ecosystems because of their rapid response to changes in the water environment.The diversity of benthic invertebrates is closely associated with the aquatic habitat area.This study examined this interaction by sampling the benthic invertebrates in an expanding area.The conclusions are that the diversity of benthic invertebrates begins to decrease when the aquatic habitat area is reduced to 45% of the original area,and decreases dramatically when the aquatic habitat area is reduced to 10% of the original area.The aquatic habitat area should be kept at more than 45% of the original area in order to maintain the significant diversity of benthic invertebrates.
360-degrees profilometry using strip-light projection coupled to Fourier phase-demodulation.
Servin, Manuel; Padilla, Moises; Garnica, Guillermo
2016-01-11
360 degrees (360°) digitalization of three dimensional (3D) solids using a projected light-strip is a well-established technique in academic and commercial profilometers. These profilometers project a light-strip over the digitizing solid while the solid is rotated a full revolution or 360-degrees. Then, a computer program typically extracts the centroid of this light-strip, and by triangulation one obtains the shape of the solid. Here instead of using intensity-based light-strip centroid estimation, we propose to use Fourier phase-demodulation for 360° solid digitalization. The advantage of Fourier demodulation over strip-centroid estimation is that the accuracy of phase-demodulation linearly-increases with the fringe density, while in strip-light the centroid-estimation errors are independent. Here we proposed first to construct a carrier-frequency fringe-pattern by closely adding the individual light-strip images recorded while the solid is being rotated. Next, this high-density fringe-pattern is phase-demodulated using the standard Fourier technique. To test the feasibility of this Fourier demodulation approach, we have digitized two solids with increasing topographic complexity: a Rubik's cube and a plastic model of a human-skull. According to our results, phase demodulation based on the Fourier technique is less noisy than triangulation based on centroid light-strip estimation. Moreover, Fourier demodulation also provides the amplitude of the analytic signal which is a valuable information for the visualization of surface details.
Saito, Masatoshi
2009-08-01
Dual-energy computed tomography (DECT) has the potential for measuring electron density distribution in a human body to predict the range of particle beams for treatment planning in proton or heavy-ion radiotherapy. However, thus far, a practical dual-energy method that can be used to precisely determine electron density for treatment planning in particle radiotherapy has not been developed. In this article, another DECT technique involving a balanced filter method using a conventional x-ray tube is described. For the spectral optimization of DECT using balanced filters, the author calculates beam-hardening error and air kerma required to achieve a desired noise level in electron density and effective atomic number images of a cylindrical water phantom with 50 cm diameter. The calculation enables the selection of beam parameters such as tube voltage, balanced filter material, and its thickness. The optimized parameters were applied to cases with different phantom diameters ranging from 5 to 50 cm for the calculations. The author predicts that the optimal combination of tube voltages would be 80 and 140 kV with Tb/Hf and Bi/Mo filter pairs for the 50-cm-diameter water phantom. When a single phantom calibration at a diameter of 25 cm was employed to cover all phantom sizes, maximum absolute beam-hardening errors were 0.3% and 0.03% for electron density and effective atomic number, respectively, over a range of diameters of the water phantom. The beam-hardening errors were 1/10 or less as compared to those obtained by conventional DECT, although the dose was twice that of the conventional DECT case. From the viewpoint of beam hardening and the tube-loading efficiency, the present DECT using balanced filters would be significantly more effective in measuring the electron density than the conventional DECT. Nevertheless, further developments of low-exposure imaging technology should be necessary as well as x-ray tubes with higher outputs to apply DECT coupled with the
Fuzzy Optimization of Construction Engineering Project Schedule Based on Critical Chain Management
Liu, Jianbing; Ren, Hong; Junshu DU
2013-01-01
Critical chain management was the very important theory innovation in the development of construction project schedule management field in recent years. Compared with the traditional methods of construction project schedule management, the methods of critical chain management considered resource constraints into construction project schedule management, the construction project cycle was shortened and the efficiency was enhanced by using the dynamic thinking and circulation pattern to manage ...
Boisbouvier, Jérôme; Bryce, David L; O'neil-Cabello, Erin; Nikonowicz, Edward P; Bax, Ad
2004-11-01
New methods are described for accurate measurement of multiple residual dipolar couplings in nucleic acid bases. The methods use TROSY-type pulse sequences for optimizing resolution and sensitivity, and rely on the E.COSY principle to measure the relatively small two-bond (2)D(CH) couplings at high precision. Measurements are demonstrated for a 24-nt stem-loop RNA sequence, uniformly enriched in (13)C, and aligned in Pf1. The recently described pseudo-3D method is used to provide homonuclear (1)H-(1)H decoupling, which minimizes cross-correlation effects and optimizes resolution. Up to seven (1)H-(13)C and (13)C-(13)C couplings are measured for pyrimidines (U and C), including (1)D(C5H5), (1)D(C6H6), (2)D(C5H6), (2)D(C6H5), (1)D(C5C4), (1)D(C5C6), and (2)D(C4H5). For adenine, four base couplings ((1)D(C2H2), (1)D(C8H8), (1)D(C4C5), and (1)D(C5C6)) are readily measured whereas for guanine only three couplings are accessible at high relative accuracy ((1)D(C8H8), (1)D(C4C5), and (1)D(C5C6)). Only three dipolar couplings are linearly independent in planar structures such as nucleic acid bases, permitting cross validation of the data and evaluation of their accuracies. For the vast majority of dipolar couplings, the error is found to be less than +/-3% of their possible range, indicating that the measurement accuracy is not limiting when using these couplings as restraints in structure calculations. Reported isotropic values of the one- and two-bond J couplings cluster very tightly for each type of nucleotide.
Economic CO2 network optimization model COCATE European project (2010-2013)
Coussy, P.; Roussanaly, S.; Bureau-Cauchois, G.; Wildenborg, T.
2013-01-01
The COCATE project is a three-year collaboration project under the EU 7th framework program for research. One of the objective of COCATE project is to tackle the problems of rolling out a shared transportation infrastructure capable of connecting geological storage sites with various CO2 emitting
Alam, Raquibul; Shang, Julie Q; Cheng, Xiangrong
2012-05-01
The oxidation of sulphidic mine tailings and consequent acid generation poses challenges for the environment. Accurate and precise analysis of sulphur content is necessary for impact assessment and management of mine tailings. Here, the authors aim at developing a rapid and easy digestion procedure, which may analyse and measure the total amount of sulphur in mine tailings by using inductively coupled plasma. For evaluating effects of several variables, the researchers used a univariate (analysis of variance (ANOVA)) strategy and considered factors such as composition of the acid mixture, heating time, and refluxing device to optimize the performance. To do the experiment, the researchers have used two certified reference materials (KZK-1 and RTS-2) and samples of tailings from Musselwhite mine. ANOVA result shows that heating time is the most influencing factor on acid digestion of the reference materials whereas in case of a digestion of tailings sample, hydrochloric acid proved to be the most significant parameter. Satisfactory results between the measured and referenced values are found for all experiments. It is found that the aqua regia (1 ml HNO(3) + 3 ml HCl) digestion of 0.1 g of samples after only 40 min of heating at 95°C produced fast, safe, and accurate analytical results with a recovery of 97% for the selected reference materials.
Saad Mutashar
2014-06-01
Full Text Available The use of wireless communication using inductive links to transfer data and power to implantable microsystems to stimulate and monitor nerves and muscles is increasing. This paper deals with the development of the theoretical analysis and optimization of an inductive link based on coupling and on spiral circular coil geometry. The coil dimensions offer 22 mm of mutual distance in air. However, at 6 mm of distance, the coils offer a power transmission efficiency of 80% in the optimum case and 73% in the worst case via low input impedance, whereas, transmission efficiency is 45% and 32%, respectively, via high input impedance. The simulations were performed in air and with two types of simulated human biological tissues such as dry and wet-skin using a depth of 6 mm. The performance results expound that the combined magnitude of the electric field components surrounding the external coil is approximately 98% of that in air, and for an internal coil, it is approximately 50%, respectively. It can be seen that the gain surrounding coils is almost constant and confirms the omnidirectional pattern associated with such loop antennas which reduces the effect of non-alignment between the two coils. The results also show that the specific absorption rate (SAR and power loss within the tissue are lower than that of the standard level. Thus, the tissue will not be damaged anymore.
A system for environmental model coupling and code reuse: The Great Rivers Project
Eckman, B.; Rice, J.; Treinish, L.; Barford, C.
2008-12-01
As part of the Great Rivers Project, IBM is collaborating with The Nature Conservancy and the Center for Sustainability and the Global Environment (SAGE) at the University of Wisconsin, Madison to build a Modeling Framework and Decision Support System (DSS) designed to help policy makers and a variety of stakeholders (farmers, fish & wildlife managers, hydropower operators, et al.) to assess, come to consensus, and act on land use decisions representing effective compromises between human use and ecosystem preservation/restoration. Initially focused on Brazil's Paraguay-Parana, China's Yangtze, and the Mississippi Basin in the US, the DSS integrates data and models from a wide variety of environmental sectors, including water balance, water quality, carbon balance, crop production, hydropower, and biodiversity. In this presentation we focus on the modeling framework aspect of this project. In our approach to these and other environmental modeling projects, we see a flexible, extensible modeling framework infrastructure for defining and running multi-step analytic simulations as critical. In this framework, we divide monolithic models into atomic components with clearly defined semantics encoded via rich metadata representation. Once models and their semantics and composition rules have been registered with the system by their authors or other experts, non-expert users may construct simulations as workflows of these atomic model components. A model composition engine enforces rules/constraints for composing model components into simulations, to avoid the creation of Frankenmodels, models that execute but produce scientifically invalid results. A common software environment and common representations of data and models are required, as well as an adapter strategy for code written in e.g., Fortran or python, that still enables efficient simulation runs, including parallelization. Since each new simulation, as a new composition of model components, requires calibration
Yao Jiang-Ming; Meng Jie; D. Pena Arteaga; P. Ring
2008-01-01
A full three-dimensional angular momentum projection on top of a triaxial relativistic mean-field calculation is implemented for the first time. The underlying Lagrangian is a point coupling model and pairing correlations are taken into account by a monopole force. This method is applied for the low-lying excited states in 24Mg. Good agreement with the experimental data is found for the ground state properties. A minimum in the potential energy surface for the 2+ state, with β≈ 0.55, γ≈ 10°, is used as the basis to investigate the rotational energyspectrum as well as the corresponding B(E2) transition probabilities as compared to the available data.
Farrara, John D.; Drummond, Leroy A.; Mechoso, Carlos R.; Spahr, Joseph A.
1998-01-01
The design, implementation and performance optimization on the CRAY T3E of an atmospheric general circulation model (AGCM) which includes the transport of, and chemical reactions among, an arbitrary number of constituents is reviewed. The parallel implementation is based on a two-dimensional (longitude and latitude) data domain decomposition. Initial optimization efforts centered on minimizing the impact of substantial static and weakly-dynamic load imbalances among processors through load redistribution schemes. Recent optimization efforts have centered on single-node optimization. Strategies employed include loop unrolling, both manually and through the compiler, the use of an optimized assembler-code library for special function calls, and restructuring of parts of the code to improve data locality. Data exchanges and synchronizations involved in coupling different data-distributed models can account for a significant fraction of the running time. Therefore, the required scattering and gathering of data must be optimized. In systems such as the T3E, there is much more aggregate bandwidth in the total system than in any particular processor. This suggests a distributed design. The design and implementation of a such distributed 'Data Broker' as a means to efficiently couple the components of our climate system model is described.
Farrara, John D.; Drummond, Leroy A.; Mechoso, Carlos R.; Spahr, Joseph A.
1998-01-01
The design, implementation and performance optimization on the CRAY T3E of an atmospheric general circulation model (AGCM) which includes the transport of, and chemical reactions among, an arbitrary number of constituents is reviewed. The parallel implementation is based on a two-dimensional (longitude and latitude) data domain decomposition. Initial optimization efforts centered on minimizing the impact of substantial static and weakly-dynamic load imbalances among processors through load redistribution schemes. Recent optimization efforts have centered on single-node optimization. Strategies employed include loop unrolling, both manually and through the compiler, the use of an optimized assembler-code library for special function calls, and restructuring of parts of the code to improve data locality. Data exchanges and synchronizations involved in coupling different data-distributed models can account for a significant fraction of the running time. Therefore, the required scattering and gathering of data must be optimized. In systems such as the T3E, there is much more aggregate bandwidth in the total system than in any particular processor. This suggests a distributed design. The design and implementation of a such distributed 'Data Broker' as a means to efficiently couple the components of our climate system model is described.
Pianowski, Giselle; Meyer, Gregory J; Villemor-Amaral, Anna Elisa de
2016-01-01
Exner ( 1989 ) and Weiner ( 2003 ) identified 3 types of Rorschach codes that are most likely to contain personally relevant projective material: Distortions, Movement, and Embellishments. We examine how often these types of codes occur in normative data and whether their frequency changes for the 1st, 2nd, 3rd, 4th, or last response to a card. We also examine the impact on these variables of the Rorschach Performance Assessment System's (R-PAS) statistical modeling procedures that convert the distribution of responses (R) from Comprehensive System (CS) administered protocols to match the distribution of R found in protocols obtained using R-optimized administration guidelines. In 2 normative reference databases, the results indicated that about 40% of responses (M = 39.25) have 1 type of code, 15% have 2 types, and 1.5% have all 3 types, with frequencies not changing by response number. In addition, there were no mean differences in the original CS and R-optimized modeled records (M Cohen's d = -0.04 in both databases). When considered alongside findings showing minimal differences between the protocols of people randomly assigned to CS or R-optimized administration, the data suggest R-optimized administration should not alter the extent to which potential projective material is present in a Rorschach protocol.
National Aeronautics and Space Administration — SynGenics Corporation proposes a program that unites mathematical and statistical processes, Response Surface Methodology, and multicriterial optimization methods to...
Extension of an Object Oriented Multidisciplinary Analysis Optimization (MDAO) Environment Project
National Aeronautics and Space Administration — Multidisciplinary design, analysis, and optimization (MDAO) tools today possess limited disciplines with little fidelity modeling capability. These tools are...
Dynamic ASE Modeling and Optimization of Aircraft with SpaRibs Project
National Aeronautics and Space Administration — We propose development and demonstration of a dynamic aeroservoelastic modeling and optimization system based on curvilinear internal structural arrangements of...
Parametric Optimization and Prediction Tool for Excavation and Prospecting Tasks Project
National Aeronautics and Space Administration — Honeybee Robotics therefore proposed to develop a software tool for facilitating prospecting and excavation system trades in support of selecting an optimal...
Liljamo, Pia; Lavander, Päivi; Kejonen, Pirjo
2016-01-01
The Oulu University Hospital's staffing management project sought information on the number of nursing staff in relation to treatment days and visits, using existing indicators to describe the activities involved. The retrospective data obtained was compared to human resources and the personnel structure. On this basis an optimal number of staff was determined for the units, taking account of a range of explanatory indicator data. The project made use of the computational model for nurse staffing and the World Health Organisation's (WHO) Workload Indicators of Staffing Need (WISN) method. The project provided extensive information on human resources issues within the units. Its results indicated the differences between wards with respect to the number and structure of resources. In addition, the nurse administrators lacked skills in gathering and using data from administrative datasets. This information will provide support for the further development of nursing operations and nursing management decision-making.
Nowack, P. J.; Abraham, N. L.; Maycock, A. C.; Braesicke, P.; Pyle, J. A.
2015-12-01
Changes in stratospheric composition can affect tropospheric composition and vice versa. Of particular interest are trace gas concentrations at the interface between these two atmospheric layers in the tropical upper troposphere and lower stratosphere (UTLS). This is due to the crucial importance of composition changes in the UTLS for the global energy budget. In a recent study (Nowack et al., 2015), we provided further evidence that composition changes in the tropical UTLS can significantly affect global warming projections. Using a state-of-the-art atmosphere-ocean chemistry-climate model, we found a ~20% smaller global warming in response to an abrupt 4xCO2 forcing if composition feedbacks were included in the calculations as compared to simulations in which composition feedbacks were not considered. We attributed this large difference in surface warming mainly to circulation-driven decreases in tropical UTLS ozone and related changes in stratospheric water vapor, partly counteracted by simultaneous changes in ice clouds. Here, we explain why this result is expected to differ between models and how, inter alia, tropospheric chemical mechanisms can contribute to this uncertainty. We highlight that improving our understanding of processes in the tropical UTLS and their representation in Earth system models remains a key challenge in climate research.Finally, taking geoengineering as a new example, we show that changes in the stratosphere can have an impact on air quality in the troposphere. In particular, we explain for a simple solar radiation management scenario how changes in surface ozone can be linked to changes in meteorology and composition in the troposphere and stratosphere. In conclusion, we highlight the importance of considering air quality impacts when evaluating a variety of geoengineering scenarios. Reference: Nowack, P.J., Abraham, N.L., Maycock, A.C., Braesicke, P., Gregory, J.M., Joshi, M.M., Osprey, A., and Pyle, J.A. Nature Climate Change 5, 41
Boguslawski, Katharina; Tecmer, Paweł; Limacher, Peter A.; Johnson, Paul A.; Ayers, Paul W.; Bultinck, Patrick; De Baerdemacker, Stijn; Van Neck, Dimitri
2014-06-01
We present a new, non-variational orbital-optimization scheme for the antisymmetric product of one-reference orbital geminal wave function. Our approach is motivated by the observation that an orbital-optimized seniority-zero configuration interaction (CI) expansion yields similar results to an orbital-optimized seniority-zero-plus-two CI expansion [L. Bytautas, T. M. Henderson, C. A. Jimenez-Hoyos, J. K. Ellis, and G. E. Scuseria, J. Chem. Phys. 135, 044119 (2011)]. A numerical analysis is performed for the C2 and LiF molecules, for the CH2 singlet diradical as well as for the symmetric stretching of hypothetical (linear) hydrogen chains. For these test cases, the proposed orbital-optimization protocol yields similar results to its variational orbital optimization counterpart, but prevents symmetry-breaking of molecular orbitals in most cases.
Ma, Denglong; Tan, Wei; Zhang, Zaoxiao; Hu, Jun
2017-03-05
In order to identify the parameters of hazardous gas emission source in atmosphere with less previous information and reliable probability estimation, a hybrid algorithm coupling Tikhonov regularization with particle swarm optimization (PSO) was proposed. When the source location is known, the source strength can be estimated successfully by common Tikhonov regularization method, but it is invalid when the information about both source strength and location is absent. Therefore, a hybrid method combining linear Tikhonov regularization and PSO algorithm was designed. With this method, the nonlinear inverse dispersion model was transformed to a linear form under some assumptions, and the source parameters including source strength and location were identified simultaneously by linear Tikhonov-PSO regularization method. The regularization parameters were selected by L-curve method. The estimation results with different regularization matrixes showed that the confidence interval with high-order regularization matrix is narrower than that with zero-order regularization matrix. But the estimation results of different source parameters are close to each other with different regularization matrixes. A nonlinear Tikhonov-PSO hybrid regularization was also designed with primary nonlinear dispersion model to estimate the source parameters. The comparison results of simulation and experiment case showed that the linear Tikhonov-PSO method with transformed linear inverse model has higher computation efficiency than nonlinear Tikhonov-PSO method. The confidence intervals from linear Tikhonov-PSO are more reasonable than that from nonlinear method. The estimation results from linear Tikhonov-PSO method are similar to that from single PSO algorithm, and a reasonable confidence interval with some probability levels can be additionally given by Tikhonov-PSO method. Therefore, the presented linear Tikhonov-PSO regularization method is a good potential method for hazardous emission
Mejia S, D.M.; Ortiz S, J.J. [ININ, 52750 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: dulcema6715@hotmail.com
2006-07-01
In this work a system coupled for the optimization of fuel recharges and control bars patterns in boiling water reactors (BWR by its initials in English) is presented. It was used a multi state recurrent neural net like optimization technique. This type of neural net has been used in the solution of diverse problems, in particular the design of patterns of control bars and the design of the fuel recharge. However, these problems have been resolved in an independent way with different optimization techniques. The system was developed in FORTRAN 77 language, it calls OCORN (Optimization of Cycles of Operation using Neural Nets) and it solves both problems of combinatory optimization in a coupled way. OCORN begins creating a seed recharge by means of an optimization through the Haling principle. Later on a pattern of control bars for this recharge seed is proposed. Then a new fuel recharge is designed using the control bars patterns previously found. By this way an iterative process begins among the optimization of control bars patterns and the fuel recharge until a stop criteria it is completed. The stop criteria is completed when the fuel recharges and the control bars patterns don't vary in several successive iterations. The final result is an optimal fuel recharge and its respective control bars pattern. In this work the obtained results by this system for a cycle of balance of 18 months divided in 12 steps of burnt are presented. The obtained results are very encouraging, since the fuel recharge and the control bars pattern, its fulfill with the restrictions imposed in each one of the problems. (Author)
A. Monroy-Villagrana; C. Cano-Sarmiento; L. Alamilla-Beltrán; H. Hernández-Sánchez; G.F. Gutiérrez-López
2014-01-01
The effect of composition (Arabic gum (AG), maltodextrin (MD), surfactants, pH) and processing parameters (pressure and number of cycles of microfluidization) of α-tocopherol (AT) emulsions was studied via a coupled Taguchi-RMS optimization. Creaming index (CI), particle size (PS) and zeta potential ( α) were selected as response variables. The estimated optimal conditions were found at GA of 40%, MD/surfactant mixture of 60%, 30% AT, pH of 4.9, P of 76 MPa and five cycles of microfluidizatio...
Bo Yang, Lingen Chen, Fengrui Sun
2012-01-01
Full Text Available An endoreversible intercooled regenerative Brayton combined heat and power (CHP plant model coupled to variable-temperature heat reservoirs is established. The exergoeconomic performance of the CHP plant is investigated using finite time thermodynamics. The analytical formulae about dimensionless profit rate and exergy efficiency of the CHP plant with the heat resistance losses in the hot-, cold- and consumer-side heat exchangers, the intercooler and the regenerator are deduced. By taking the maximum profit rate as the objective, the heat conductance allocation among the five heat exchangers and the choice of intercooling pressure ratio are optimized by numerical examples, the characteristic of the optimal dimensionless profit rate versus corresponding exergy efficiency is investigated. When the optimization is performed further with respect to the total pressure ratio, a double-maximum profit rate is obtained. The effects of the design parameters on the double-maximum dimensionless profit rate and corresponding exergy efficiency, optimal total pressure ratio and optimal intercooling pressure ratio are analyzed in detail, and it is found that there exist an optimal consumer-side temperature and an optimal thermal capacitance rate matching between the working fluid and the heat reservoir, respectively, corresponding to a thrice-maximum dimensionless profit rate.
Yang, Bo; Chen, Lingen; Sun, Fengrui [College of Naval Architecture and Power, Naval University of Engineering, Wuhan 430033 (China)
2012-07-01
An endoreversible intercooled regenerative Brayton combined heat and power (CHP) plant model coupled to variable-temperature heat reservoirs is established. The exergoeconomic performance of the CHP plant is investigated using finite time thermodynamics. The analytical formulae about dimensionless profit rate and exergy efficiency of the CHP plant with the heat resistance losses in the hot-, cold- and consumer-side heat exchangers, the intercooler and the regenerator are deduced. By taking the maximum profit rate as the objective, the heat conductance allocation among the five heat exchangers and the choice of intercooling pressure ratio are optimized by numerical examples, the characteristic of the optimal dimensionless profit rate versus corresponding exergy efficiency is investigated. When the optimization is performed further with respect to the total pressure ratio, a double-maximum profit rate is obtained. The effects of the design parameters on the double-maximum dimensionless profit rate and corresponding exergy efficiency, optimal total pressure ratio and optimal intercooling pressure ratio are analyzed in detail, and it is found that there exist an optimal consumer-side temperature and an optimal thermal capacitance rate matching between the working fluid and the heat reservoir, respectively, corresponding to a thrice-maximum dimensionless profit rate.
National Aeronautics and Space Administration — Future adaptive, smart air vehicles will continually tune themselves using sophisticated on-board health management and on-the-fly optimization of performance...
National Aeronautics and Space Administration — In this effort, ZONA Technology, Inc aims at developing an innovative multi-fidelity and multi-disciplinary optimization (MDO) sub-framework that can (i) effectively...
Parametric Optimization and Prediction Tool for Lunar Surface Systems Excavation Tasks Project
National Aeronautics and Space Administration — Honeybee Robotics proposes to develop a software tool for facilitating lunar excavation system trades in support of selecting an optimal architecture. This will...
Mass-Optimized Ultra Flex Solar Array with Integrated IMM Cell Flexible Blanket Project
National Aeronautics and Space Administration — Deployable Space Systems (DSS), in partnership with ATK Space and EMCORE, is focusing on the design development and optimization of the most promising advanced space...
Optimization of CZT Detectors with Sub-mm Pixel Pitches Project
National Aeronautics and Space Administration — We propose to develop and optimize 0.5 cm thick Cadmium Zinc Telluride (CZT) detectors with very small pixel pitches, i.e. 350 micron and 600 micron. The proposed...
van Deventer, Claire; Golden, Lauren; du Plessis, Erica; Lion-Cachet, Carien
2017-01-01
.... The referral pattern is true for paediatric patients as well. With the added complexity of managing children, there was a concern in the research district that children were not being optimally managed at PHC level. Method...
Mass-Optimized UltraFlex Solar Array with Integrated IMM Cell Flexible Blanket Project
National Aeronautics and Space Administration — Deployable Space Systems (DSS), in partnership with ATK Space and EMCORE, will focus the proposed SBIR program on the optimization and design development of the most...
National Aeronautics and Space Administration — Advanced, robust, autonomous planning systems have not focused on the scheduling decisions made by the planner. And high quality, optimizing schedulers have rarely...
Multi-Fidelity Multi-Strategy and Multi-Disciplinary Design Optimization Environment Project
National Aeronautics and Space Administration — Multidisciplinary design and optimization (MDO) tools developed to perform multi-disciplinary analysis based on low fidelity computation methods have been used in...
Drag &Drop, Mixed-Methodology-based Lab-on-Chip Design Optimization Software Project
National Aeronautics and Space Administration — The overall objective is to develop a ?mixed-methodology?, drag and drop, component library (fluidic-lego)-based, system design and optimization tool for complex...
Johnson, Gary E.; Khan, Fenton; Ploskey, Gene R.; Hughes, James S.; Fischer, Eric S.
2010-08-18
The goal of the study was to optimize performance of the fixed-location hydroacoustic systems at Lookout Point Dam (LOP) and the acoustic imaging system at Cougar Dam (CGR) by determining deployment and data acquisition methods that minimized structural, electrical, and acoustic interference. The general approach was a multi-step process from mount design to final system configuration. The optimization effort resulted in successful deployments of hydroacoustic equipment at LOP and CGR.
黄涛; 袁东立; 王永红; 张昕宇
2012-01-01
Based on the characteristics of heat load in cold region, the coupled system with solar energy and ground source heat pump is designed for the actual project. The thermal equilibrium computation of the system is analyzed in detail, and the operation mode of supplementing heat by utilizing solar energy is optimized. In this system, the high efficient and stable running are ensured in design and the advantages of energy conservation and environmental protection are prominent.%针对严寒地区的负荷特点,并结合实际项目,设计一套太阳能-地源热泵耦合系统.对系统的热平衡进行计算分析,优化太阳能的补热运行方式,保证系统在严寒地区高效、稳定运行,系统的节能环保效益显著.
M. Steinacher
2009-04-01
Full Text Available Ocean acidification from the uptake of anthropogenic carbon is simulated for the industrial period and IPCC SRES emission scenarios A2 and B1 with a global coupled carbon cycle-climate model. Earlier studies identified seawater saturation state with respect to aragonite, a mineral phase of calcium carbonate, as a key variable governing impacts on corals and other shell-forming organisms. Globally in the A2 scenario, water saturated by more than 300%, considered suitable for coral growth, vanishes by 2070 AD (CO_{2}≈630 ppm, and the ocean volume fraction occupied by saturated water decreases from 42% to 25% over this century. The largest simulated pH changes worldwide occur in Arctic surface waters, where hydrogen ion concentration increases by up to 185% (ΔpH=−0.45. Projected climate change amplifies the decrease in Arctic surface mean saturation and pH by more than 20%, mainly due to freshening and increased carbon uptake in response to sea ice retreat. Modeled saturation compares well with observation-based estimates along an Arctic transect and simulated changes have been corrected for remaining model-data differences in this region. Aragonite undersaturation in Arctic surface waters is projected to occur locally within a decade and to become more widespread as atmospheric CO_{2} continues to grow. The results imply that surface waters in the Arctic Ocean will become corrosive to aragonite, with potentially large implications for the marine ecosystem, if anthropogenic carbon emissions are not reduced and atmospheric CO_{2} not kept below 450 ppm.
Rutqvist, J.; Dobson, P.F.; Oldenburg, C.M.; Garcia, J.; Walters, M.
2010-10-20
This paper presents activities and results associated with Phase 1 (pre-stimulation phase) of an Enhanced Geothermal System (EGS) demonstration project at the northwest part of The Geysers geothermal field, California. The paper presents development of a 3-D geological model, coupled thermal-hydraulic-mechanical (THM) modeling of proposed stimulation injection as well as current plans for stimulation and monitoring of the site. The project aims at creating an EGS by directly and systematically injecting cool water at relatively low pressure into a known High Temperature (about 280 to 350 C) Zone (HTZ) located under the conventional (240 C) steam reservoir at depths of {approx}3 km. Accurate micro-earthquake monitoring initiated before the start of the injection will be used as a tool for tracking the development of the EGS and monitoring changes in microseismicity. We first analyzed historic injection and micro-earthquake data from an injection well (Aidlin 11) located about 3 miles to the west of the new EGS demonstration area. Thereafter, we used the same modeling approach to predict the likely extent of the zone of enhanced permeability for a proposed initial injection in two wells (Prati State 31 and Prati 32) at the new EGS demonstration area. Our modeling indicates that the proposed injection scheme will provide additional steam production in the area by creating a zone of permeability enhancement extending about 0.5 km from each injection well which will connect to the overlying conventional steam reservoir, in agreement with the conclusions of Nielson and Moore (2000).
Ely, James H.; Siciliano, Edward R.; Swinhoe, Martyn T.; Lintereur, Azaree T.
2013-01-01
This report details the results of the modeling and simulation work accomplished for the ‘Neutron Detection without Helium-3’ project during the 2011 and 2012 fiscal years. The primary focus of the project is to investigate commercially available technologies that might be used in safeguards applications in the relatively near term. Other technologies that are being developed may be more applicable in the future, but are outside the scope of this study.
Yudi, Xiao; Xingkui, Mao; Mao, Lin
2017-01-01
The coupled magnetic resonant unit (CMRU) has great effect on the transmitting power capability and efficiency of magnetic resonant wireless power transfer system. The key objective i.e. the efficiency coefficient kQ is introduced in the design of CMRU or the coupled windings based on the mutual ...
Design optimization of 600 A-13 kA current leads for the Large Hadron Collider project at CERN
Spiller, D M; Al-Mosawl, M K; Friend, C M; Thacker, P; Ballarino, A
2001-01-01
The requirements of the Large Hadron Collider project at CERN for high-temperature superconducting (HTS) current leads have been widely publicized. CERN require hybrid current leads of resistive and HTS materials with current ratings of 600 A, 6 kA and 13 kA. BICC General Superconductors, in collaboration with the University of Southampton, have developed and manufactured prototype current leads for the Large Hadron Collider project. The resistive section consists of a phosphorus de-oxidized copper conductor and heat exchanger and the HTS section is constructed from BICC General's (Pb, Bi)2223 tapes with a reduced thermal conductivity Ag alloy sheath. We present the results of the materials optimization studies for the resistive and the HTS sections. Some results of the acceptance tests at CERN are discussed. (9 refs).
Peihua GUO; Detong ZHU
2008-01-01
The authors propose an affine scaling modified gradient path method in association with reduced projective Hessian and nonmonotonic interior backtracking line search techniques for solving the linear equality constrained optimization subject to bounds on variables. By employing the QR decomposition of the constraint matrix and the eigensystem decomposition of reduced projective Hes-sian matrix in the subproblem, the authors form affine scaling modified gradient curvilinear path very easily. By using interior backtracking line search technique, each iterate switches to trial step of strict interior feasibility. The global convergence and fast local superlinear/quadratical convergence rates of the proposed algorithm are established under some reasonable conditions. A nonmonotonic criterion should bring about speeding up the convergence progress in some ill-conditioned cases. The results of numerical experiments are reported to show the effectiveness of the proposed algorithm.
Delahaye, P; Angot, J; Cam, J F; Traykov, E; Ban, G; Celona, L; Choinski, J; Gmaj, P; Jardin, P; Koivisto, H; Kolhinen, V; Lamy, T; Maunoury, L; Patti, G; Thuillier, T; Tarvainen, O; Vondrasek, R; Wenander, F
2016-01-01
The present paper summarizes the results obtained from the past few years in the framework of the Enhanced Multi-Ionization of short-Lived Isotopes for Eurisol (EMILIE) project. The EMILIE project aims at improving the charge breeding techniques with both Electron Cyclotron Resonance Ion Sources (ECRIS) and Electron Beam Ion Sources (EBISs) for European Radioactive Ion Beam (RIB) facilities. Within EMILIE, an original technique for debunching the beam from EBIS charge breeders is being developed, for making an optimal use of the capabilities of CW post-accelerators of the future facilities. Such a debunching technique should eventually resolve duty cycle and time structure issues which presently complicate the data-acquisition of experiments. The results of the first tests of this technique are reported here. In comparison with charge breeding with an EBIS, the ECRIS technique had lower performance in efficiency and attainable charge state for metallic ion beams and also suffered from issues related to beam c...
Wu, Xushu; Wang, Zhaoli; Guo, Shenglian; Liao, Weilin; Zeng, Zhaoyang; Chen, Xiaohong
2017-04-01
One major threat to cities at present is the increased inundation hazards owing to changes in climate and accelerated human activity. Future evolution of urban inundation is still an unsolved issue, given large uncertainties in future environmental conditions within urbanized areas. Developing model techniques and urban inundation projections are essential for inundation management. In this paper, we proposed a 2D hydrodynamic inundation model by coupling SWMM and LISFLOOD-FP models, and revealed how future urban inundation would evolve for different storms, sea level rise and subsidence scenarios based on the developed model. The Shiqiao Creek District (SCD) in Dongguan City was used as the case study. The model ability was validated against the June 13th, 2008 inundation event, which occurred in SCD, and proved capable of simulating dynamic urban inundation. Scenario analyses revealed a high degree of consistency in the inundation patterns among different storms, with larger magnitudes corresponding to greater return periods. Inundations across SCD generally vary as a function of storm intensity, but for lowlands or regions without drainage facilities inundations tend to aggravate over time. In riverfronts, inundations would exacerbate with sea level rise or subsidence; however, the inland inundations are seemingly insensitive to both factors. For the combined scenario of 100-yr storm, 0.5 m subsidence and 0.7 m sea level rise, the riverside inundations would occur much in advance, whilst catastrophic inundations sweep across SCD. Furthermore, the optimal low-impact development found for this case study includes 0.2 km2 of permeable pavements, 0.1 km2 of rain barrels and 0.7 km2 of green roofs.
O'Brien, Ricky T.; Cooper, Benjamin J.; Keall, Paul J.
2013-03-01
Four dimensional cone beam computed tomography (4DCBCT) is an emerging clinical image guidance strategy for tumour sites affected by respiratory motion. In current generation 4DCBCT techniques, both the gantry rotation speed and imaging frequency are constant and independent of the patient’s breathing which can lead to projection clustering. We present a mixed integer quadratic programming (MIQP) model for respiratory motion guided-4DCBCT (RMG-4DCBCT) which regulates the gantry velocity and projection time interval, in response to the patient’s respiratory signal, so that a full set of evenly spaced projections can be taken in a number of phase, or displacement, bins during the respiratory cycle. In each respiratory bin, an image can be reconstructed from the projections to give a 4D view of the patient’s anatomy so that the motion of the lungs, and tumour, can be observed during the breathing cycle. A solution to the full MIQP model in a practical amount of time, 10 s, is not possible with the leading commercial MIQP solvers, so a heuristic method is presented. Using parameter settings typically used on current generation 4DCBCT systems (4 min image acquisition, 1200 projections, 10 respiratory bins) and a sinusoidal breathing trace with a 4 s period, we show that the root mean square (RMS) of the angular separation between projections with displacement binning is 2.7° using existing constant gantry speed systems and 0.6° using RMG-4DCBCT. For phase based binning the RMS is 2.7° using constant gantry speed systems and 2.5° using RMG-4DCBCT. The optimization algorithm presented is a critical step on the path to developing a system for RMG-4DCBCT.
李奇睿; 王继军
2011-01-01
针对退耕还林还草工程实施后商品型生态农业系统耦合关系的变化情况,运用农业生态经济系统耦合度模型,对安塞县商品型生态农业系统耦合演变过程进行了分析.结果表明:商品型生态农业系统耦合演变过程可以划分为4个阶段:协调发展阶段、耗损发展阶段、胁迫发展阶段、恢复重建阶段.1998-2008年,安塞县商品型生态农业系统生态、经济综合指数明显增高,系统祸合演变过程经历了“胁迫衰退、恢复重建和协调发展”阶段.依据耦合度拟合曲线及所划分的耦合态势类型,目前安塞县商品型生态农业系统耦合关系处于不断协调过程中,通过优化农业资源结构,提高产业与资源一致性,有望形成良性耦合态势.%Based on changes in the coupling relationship of ecological agro-system of commodities (EASC) under "Grain for Green Project", the coupling evolution of agricultural eco-economic system in Ansai County was analyzed by utilizing the coupling degree model. The results showed that the coupling evolution of EASC could be compartmentalized into 4 phases: coordinated development, worn development, stressed degeneration, and reconversion. The composite evaluation index of agricultural eco-economic system in Ansai County was enhanced significantly from 1998 to 2008. The coupling evolution in Ansai County had experienced the stressed degeneration, reconversion and coordinated development phase. According to coupling degree fitting curves and coupling type classification, the current coupling relationship of EASC in Ansai County was in continual harmonizing situation. In future, positive coupling situation would be formed by optimizing the structure of agricultural resources and enhancing the consistency between agricultural production and resources.
Chang, C.; Borgart, A.; Chen, A.; Hendriks, M.A.N.
2014-01-01
This paper proposes an efficient and reliable topology optimization method that can obtain a black and white solution with a low objective function value within a few tens of iterations. First of all, a transformation of variables technique is adopted to eliminate the constraints on the design varia
LU Wei-ji; CUI Wei
2001-01-01
In this paper, two kinds of models are presented and optimized for pro ject investment risk income on the basis of probability χ distribution. One kin d of model being proved has only a maximal value and another kind being proved h as no extreme values.
Garcia, Carolyn M; Aguilera-Guzman, Rosa Maria; Lindgren, Sandi; Gutierrez, Rodolfo; Raniolo, Blanca; Genis, Therese; Vazquez-Benitez, Gabriela; Clausen, Lisa
2013-09-01
Intergenerational photovoice groups are promising for promoting health through the topic that is explored and through group dynamics that can foster healthy relationships and communication. To investigate the potential benefits of intergenerational photovoice projects, photovoice groups were conducted in urban Minnesota, United States, and in rural Morelos, Mexico, between 2009 and 2012 with Mexican-origin adults and their adolescent relatives. Seven photovoice groups of adult-adolescent dyads met for eight sessions and developed exhibits highlighting their views on health and migration and made policy recommendations, using messages conveyed through their words and photographs. Informal process evaluation and focus groups were used to elicit feedback about photovoice project participation. Photovoice project themes were descriptively analyzed. Focus group evaluation data were thematically summarized, and facilitator reflections were descriptively summarized to identify factors associated with intergenerational photovoice groups. Seventy-five participants were recruited. Photovoice themes represented effects of migration on health, family, and well-being. The following two evaluative themes were identified: (a) participant sentiments about the benefits of photovoice participation and (b) facilitator observations of intergenerational photovoice group benefits and challenges. Participants described opportunities to learn new things and barriers to healthy relationships that the project was eliminating by providing them with time to work together. Used in health promotion, photovoice is a valuable tool that contributes to understanding the complex underlying factors influencing behaviors and health.
Li, Rui; Roberti, Roberto
2017-01-01
This paper addresses the railway track possession scheduling problem (RTPSP), where a large-scale railway infrastructure project consisting of multiple construction works is to be planned. The RTPSP is to determine when to perform the construction works and in which track possessions while satisf...
Optimization of Overall Project of ChinaLEad-Alloy Cooled Reactor
DUAN; Tian-ying; LONG; Bin; HU; Yun; LIU; Xing-ming; SUN; Gang; LIU; Yi-zhe; YANG; Yong; PEI; Zhi-yong; FENG; Wei-wei; YU; Xiao
2012-01-01
<正>The application of accelerator driven sub-critical reactor which is able to transmute spent fuel and long-lived radioactive fission products is highly concerned in the international research projects. Lots of researches have been done in many countries. While China Institute of Atomic Energy has built a fast
Ng, Melissa R. [Ohlone College, Fremont, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Moran, Bryan [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bekker, Logan [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dudukovic, Nikola [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2016-08-12
Large Area Projection Microstereolithography (LAPμSL) is a new technology that allows the additive manufacture of parts that have feature sizes spanning from centimeters to tens of microns. Knowing the accuracy of builds from a system like this is a crucial step in development. This project explored the capabilities of the second and newest LAPμSL system that was built by comparing the features of actual builds to the desired structures. The system was then characterized in order to achieve the best results. The photo polymeric resins that were used were Autodesk PR48 and HDDA. Build parameters for Autodesk PR48 were found that allowed the prints to progress while using the full capacity of the system to print quality parts in a relatively short amount of time. One of the larger prints in particular had a print time that was nearly eighteen times faster than it would have been had printed in the first LAPμSL system. The characterization of HDDA resin helped the understanding that the flux of the light projected into the resin also affected the quality of the builds, rather than just the dose of light given. Future work for this project includes exploring the use of other resins in the LAPμSL systems, exploring the use of Raman Spectroscopy to analyze builds, and completing the characterization of the LAPμSL system.
Abe, Steffen; Krieger, Lars; Deckert, Hagen
2017-04-01
The changes of fluid pressures related to the injection of fluids into the deep underground, for example during geothermal energy production, can potentially reactivate faults and thus cause induced seismic events. Therefore, an important aspect in the planning and operation of such projects, in particular in densely populated regions such as the Upper Rhine Graben in Germany, is the estimation and mitigation of the induced seismic risk. The occurrence of induced seismicity depends on a combination of hydraulic properties of the underground, mechanical and geometric parameters of the fault, and the fluid injection regime. In this study we are therefore employing a numerical model to investigate the impact of fluid pressure changes on the dynamics of the faults and the resulting seismicity. The approach combines a model of the fluid flow around a geothermal well based on a 3D finite difference discretisation of the Darcy-equation with a 2D block-slider model of a fault. The models are coupled so that the evolving pore pressure at the relevant locations of the hydraulic model is taken into account in the calculation of the stick-slip dynamics of the fault model. Our modelling approach uses two subsequent modelling steps. Initially, the fault model is run by applying a fixed deformation rate for a given duration and without the influence of the hydraulic model in order to generate the background event statistics. Initial tests have shown that the response of the fault to hydraulic loading depends on the timing of the fluid injection relative to the seismic cycle of the fault. Therefore, multiple snapshots of the fault's stress- and displacement state are generated from the fault model. In a second step, these snapshots are then used as initial conditions in a set of coupled hydro-mechanical model runs including the effects of the fluid injection. This set of models is then compared with the background event statistics to evaluate the change in the probability of
Wei, Lei; Alkeskjold, Thomas Tanggaard; Bjarklev, Anders Overgaard
2009-01-01
SU-8 structures are built up to increase the fiber coupling efficiency of liquid crystal photonic bandgap fiber components. The resolution reduction of UV exposure is minimized to 4%, and insertion loss is reduced to 2.7dB.......SU-8 structures are built up to increase the fiber coupling efficiency of liquid crystal photonic bandgap fiber components. The resolution reduction of UV exposure is minimized to 4%, and insertion loss is reduced to 2.7dB....
Optimizing Work Zones for Two-Lane Urban Road Maintenance Projects
HUANG Qian; SHI Jing
2008-01-01
Road maintenance work brings costs to the govemment and delays to users.The setting up of work zones often leads to severe congestion during peak hours,especially in busy urban areas.A road maintenance delay model is presented here that includes consideration of excessive traffic flow and non-motorists.A trial-and-error method is used to find the optimal work zone length and the best work starting time to minimize the total cost of maintenance and delays.A numerical example with a sensitivity analysis is also given.The results show that optimal starting time is not sensitive to the flow speed and the increase of work zone speeds sharply reduces the total cost when the road is congested.
Hao Jin
2015-01-01
Full Text Available Steel-spring floating slab tracks are one of the most effective methods to reduce vibrations from underground railways, which has drawn more and more attention in scientific communities. In this paper, the steel-spring floating slab track located in Track Vibration Abatement and Control Laboratory was modeled with four-pole parameter method. The influences of the fastener damping ratio, the fastener stiffness, the steel-spring damping ratio, and the steel-spring stiffness were researched for the rail displacement and the foundation acceleration. Results show that the rail displacement and the foundation acceleration will decrease with the increase of the fastener stiffness or the steel-spring damping ratio. However, the rail displacement and the foundation acceleration have the opposite variation tendency for the fastener damping ratio and the steel-spring stiffness. In order to optimize the rail displacement and the foundation acceleration affected by the fastener damping ratio and the steel-spring stiffness at the same time, a multiobjective ant colony optimization (ACO was employed. Eventually, Pareto optimal frontier of the rail displacement and the foundation acceleration was derived. Furthermore, the desirable values of the fastener damping ratio and the steel-spring stiffness can be obtained according to the corresponding Pareto optimal solution set.
Li, Ji; Hu, Guoqing; Zhou, Yonghong; Zou, Chong; Peng, Wei; Alam Sm, Jahangir
2017-04-19
As a high performance-cost ratio solution for differential pressure measurement, piezo-resistive differential pressure sensors are widely used in engineering processes. However, their performance is severely affected by the environmental temperature and the static pressure applied to them. In order to modify the non-linear measuring characteristics of the piezo-resistive differential pressure sensor, compensation actions should synthetically consider these two aspects. Advantages such as nonlinear approximation capability, highly desirable generalization ability and computational efficiency make the kernel extreme learning machine (KELM) a practical approach for this critical task. Since the KELM model is intrinsically sensitive to the regularization parameter and the kernel parameter, a searching scheme combining the coupled simulated annealing (CSA) algorithm and the Nelder-Mead simplex algorithm is adopted to find an optimal KLEM parameter set. A calibration experiment at different working pressure levels was conducted within the temperature range to assess the proposed method. In comparison with other compensation models such as the back-propagation neural network (BP), radius basis neural network (RBF), particle swarm optimization optimized support vector machine (PSO-SVM), particle swarm optimization optimized least squares support vector machine (PSO-LSSVM) and extreme learning machine (ELM), the compensation results show that the presented compensation algorithm exhibits a more satisfactory performance with respect to temperature compensation and synthetic compensation problems.
Alexander Mikhajlovich Tarasyev
2014-09-01
Full Text Available In this paper, we develop an economic growth model taking into account two factors of production: fixed capital and labor force, to study the dynamics of GDP growth. The dependence of the output of these factors is described by a production function of the exponential type. Within the framework of the optimal control theory, the optimization problem for investment levels is being solved to maximize the integral index of consumption. We study the qualitative properties of optimal trajectories as solutions of the Hamiltonian systems arising in Pontryagin’s maximum principle. The sensitivity analysis of the equilibrium solutions of the economic system is implemented with respect to the elasticity coefficients of the production function, the depreciation rate of the capital, and the discount factor, and growth trends are indicated. The econometric analysis of the model parameters is provided basing on real data for the Russian economy. In accordance with the results of the regression analysis, the projection of economic development is constructed in conditions of the applicability of the economic growth model.
Dardour, S
2007-04-15
This work deals with modelling, simulation and optimization of the coupling between nuclear reactors (PWR, modular high temperature reactors) and desalination processes (multiple effect distillation, reverse osmosis). The reactors considered in this study are PWR (Pressurized Water Reactor) and GTMHR (Gas Turbine Modular Helium Reactor). The desalination processes retained are MED (Multi Effect Distillation) and SWRO (Sea Water Reverse Osmosis). A software tool: EXCELEES of thermodynamic modelling of coupled systems, based on the Engineering Algebraic Equation Solver has been developed. Models of energy conversion systems and of membrane desalination processes and distillation have been developed. Based on the first and second principles of thermodynamics, these models have allowed to determine the optimal running point of the coupled systems. The thermodynamic analysis has been completed by a first economic evaluation. Based on the use of the DEEP software of the IAEA, this evaluation has confirmed the interest to use these types of reactors for desalination. A modelling tool of thermal processes of desalination in dynamic condition has been developed too. This tool has been applied to the study of the dynamics of an existing plant and has given satisfying results. A first safety checking has been at last carried out. The transients able to jeopardize the integrated system have been identified. Several measures aiming at consolidate the safety have been proposed. (O.M.)
Wei-Neng Chen; Jun Zhang
2012-01-01
Project scheduling under uncertainty is a challenging field of research that has attracted increasing attention.While most existing studies only consider the single-mode project scheduling problem under uncertainty,this paper aims to deal with a more realistic model called the stochastic multi-mode resource constrained project scheduling problem with discounted cash flows (S-MRCPSPDCF).In the model,activity durations and costs are given by random variables.The objective is to find an optimal baseline schedule so that the expected net present value (NPV) of cash flows is maximized.To solve the problem,an ant colony system (ACS) based approach is designed.The algorithm dispatches a group of ants to build baseline schedules iteratively using pheromones and an expected discounted cost (EDC) heuristic.Since it is impossible to evaluate the expected NPV directly due to the presence of random variables,the algorithm adopts the Monte Carlo (MC)simulation technique.As the ACS algorithm only uses the best-so-far solution to update pheromone values,it is found that a rough simulation with a small number of random scenarios is enough for evaluation.Thus the computational cost is reduced.Experimental results on 33 instances demonstrate the effectiveness of the proposed model and the ACS approach.
Coupled transfers; Transferts couples
Nicolas, X.; Lauriat, G.; Jimenez-Rondan, J. [Universite de Marne-la-Vallee, Lab. d' Etudes des Transferts d' Energie et de Matiere (LETEM), 77 (France); Bouali, H.; Mezrhab, A. [Faculte des Sciences, Dept. de Physique, Lab. de Mecanique et Energetique, Oujda (Morocco); Abid, C. [Ecole Polytechnique Universitaire de Marseille, IUSTI UMR 6595, 13 Marseille (France); Stoian, M.; Rebay, M.; Lachi, M.; Padet, J. [Faculte des Sciences, Lab. de Thermomecanique, UTAP, 51 - Reims (France); Mladin, E.C. [Universitaire Polytechnique Bucarest, Faculte de Genie Mecanique, Bucarest (Romania); Mezrhab, A. [Faculte des Sciences, Lab. de Mecanique et Energetique, Dept. de Physique, Oujda (Morocco); Abid, C.; Papini, F. [Ecole Polytechnique, IUSTI, 13 - Marseille (France); Lorrette, C.; Goyheneche, J.M.; Boechat, C.; Pailler, R. [Laboratoire des Composites ThermoStructuraux, UMR 5801, 33 - Pessac (France); Ben Salah, M.; Askri, F.; Jemni, A.; Ben Nasrallah, S. [Ecole Nationale d' Ingenieurs de Monastir, Lab. d' Etudes des Systemes Thermiques et Energetiques (Tunisia); Grine, A.; Desmons, J.Y.; Harmand, S. [Laboratoire de Mecanique et d' Energetique, 59 - Valenciennes (France); Radenac, E.; Gressier, J.; Millan, P. [ONERA, 31 - Toulouse (France); Giovannini, A. [Institut de Mecanique des Fluides de Toulouse, 31 (France)
2005-07-01
This session about coupled transfers gathers 30 articles dealing with: numerical study of coupled heat transfers inside an alveolar wall; natural convection/radiant heat transfer coupling inside a plugged and ventilated chimney; finite-volume modeling of the convection-conduction coupling in non-stationary regime; numerical study of the natural convection/radiant heat transfer coupling inside a partitioned cavity; modeling of the thermal conductivity of textile reinforced composites: finite element homogenization on a full periodical pattern; application of the control volume method based on non-structured finite elements to the problems of axisymmetrical radiant heat transfers in any geometries; modeling of convective transfers in transient regime on a flat plate; a conservative method for the non-stationary coupling of aero-thermal engineering codes; measurement of coupled heat transfers (forced convection/radiant transfer) inside an horizontal duct; numerical simulation of the combustion of a water-oil emulsion droplet; numerical simulation study of heat and mass transfers inside a reactor for nano-powders synthesis; reduction of a combustion and heat transfer model of a direct injection diesel engine; modeling of heat transfers inside a knocking operated spark ignition engine; heat loss inside an internal combustion engine, thermodynamical and flamelet model, composition effects of CH{sub 4}H{sub 2} mixtures; experimental study and modeling of the evolution of a flame on a solid fuel; heat transfer for laminar subsonic jet of oxygen plasma impacting an obstacle; hydrogen transport through a A-Si:H layer submitted to an hydrogen plasma: temperature effects; thermal modeling of the CO{sub 2} laser welding of a magnesium alloy; radiant heat transfer inside a 3-D environment: application of the finite volume method in association with the CK model; optimization of the infrared baking of two types of powder paints; optimization of the emission power of an infrared
Hagspiel, Simeon; Jaegemann, Cosima; Lindenberger, Dietmar [Koeln Univ. (Germany). Inst. of Energy Economics; Cherevatskiy, Stanislav; Troester, Eckehard; Brown, Tom [Energynautics GmbH, Langen (Germany)
2012-07-01
Electricity market models, implemented as dynamic programming problems, have been applied widely to identify possible pathways towards a cost-optimal and low carbon electricity system. However, the joint optimization of generation and transmission remains challenging, mainly due to the fact that different characteristics and rules apply to commercial and physical exchanges of electricity in meshed networks. This paper presents a methodology that allows to optimize power generation and transmission infrastructures jointly through an iterative approach based on power transfer distribution factors (PTDFs). As PTDFs are linear representations of the physical load flow equations, they can be implemented in a linear programming environment suitable for large scale problems such as the European power system. The algorithm iteratively updates PTDFs when grid infrastructures are modified due to cost-optimal extension and thus yields an optimal solution with a consistent representation of physical load flows. The method is demonstrated on a simplified three-node model where it is found to be stable and convergent. It is then scaled to the European level in order to find the optimal power system infrastructure development under the prescription of strongly decreasing CO{sub 2} emissions in Europe until 2050 with a specific focus on photovoltaic (PV) power. (orig.)
Lufan Zhang
2017-01-01
Full Text Available Flexure hinge mechanism plays a key part in realization of terminal nano-positioning. The performance of flexure hinge mechanism is determined by its positioning design. Based on the actual working conditions, its finite element model is built and calculated in ANSYS. Moreover, change trends of deformation and natural frequency with positioning design parameters are revealed. And sensitivity analysis is performed for exploration response to these parameters. These parameters are used to build four objective functions. To solve it conveniently, the multi-objective optimization problem is transferred to the form of single-objective function with constraints. An optimal mechanism is obtained by an optimization method combining ANSYS with MATLAB. Finite element numerical simulation has been carried out to demonstrate the superiority of the optimal flexure hinge mechanism, and the superiority can be further verified by experiment. Measurements and tests have been conducted at varying accelerations, velocities, and displacements, to quantify and characterize the amount of acceleration responses obtained from flexure hinge mechanism before and after optimization. Both time- and frequency-domain analyses of experimental data show that the optimal flexure hinge mechanism has superior effectiveness. It will provide a basic for realizing high acceleration and high precision positioning of macro–micro motion platform.
Optimal Selection Method for Investment Project Investicinių projektų optimalios atrankos metodas
Vytautas Jonas Žilinskas
2011-02-01
Full Text Available
Under the modern world market conditions the investment activity of enterprises is increasing. Therefore, one of the main aspects of the investment activity guarantee is a selection and apprehension of the main principles of the investment control and possi-bilities of different uses of the investment instruments. For the optimum selection of the investment projects it is suggested to use a formalistic experimental author’s modified method of priority allocation and selection, which gives an opportunity to evaluate the investment project according to different partial criteria and their meaning of importance. Working out this way a complex evaluation of each chosen investment project is obtai-ned. Using the suggested MPSP (modified method of priority allocation and selection the investment projects are evaluated with qualitative and quantitative criteria. So this method can be used when qualitative criteria of evaluation are predominated. Formalis-tic methods of analysis cannot be used to establish quantitative criteria and those small projects when it is relatively too expensive to apply other usual methods of the financial economic analysis. Method MPSP selection is universal and ordinary so it can be used to establish the efficiency of different projects, to classify projects, to model the strategy of the state economy. If you like to control the realization of the chosen investment project more effectively and rationally it is suggested to use PERT (Program Evaluation and Review Technique.The main control elements of the investment project are reviewed in the article using PERT which is useful to draw up an optimistic reticular schedule of the investment work implementation.
Energy acceptance and on momentum aperture optimization for the Sirius project
Dester, P. S.; Sá, F. H.; Liu, L.
2017-07-01
A fast objective function to calculate Touschek lifetime and on momentum aperture is essential to explore the vast search space of strength of quadrupole and sextupole families in Sirius. Touschek lifetime is estimated by using the energy aperture (dynamic and physical), RF system parameters and driving terms. Non-linear induced betatron oscillations are considered to determine the energy aperture. On momentum aperture is estimated by using a chaos indicator and resonance crossing considerations. Touschek lifetime and on momentum aperture constitute the objective function, which was used in a multi-objective genetic algorithm to perform an optimization for Sirius.
Optimization of Organization Structure of Oversea EPC Projects%海外EPC项目组织结构优化探讨
孙玉祥; 张帆
2012-01-01
通过对海外EPC项目实践经验的总结和反思,结合项目管理理论,对海外EPC项目组织结构、流程管理的优化进行探讨.并应结合企业管理体系和工程特点优化项目组织结构.%Based on the practical experience and re-think about oversea EPC project, combined with the project management theory, this paper discusses how to optimize the organization structure and workflow management of oversea projects, and the project's organization structure should be optimized according to the enterprise management system and project characteristics.
Rahnema, Farzad; Garimeela, Srinivas; Ougouag, Abderrafi; Zhang, Dingkang
2013-11-29
This project will develop a 3D, advanced coarse mesh transport method (COMET-Hex) for steady- state and transient analyses in advanced very high-temperature reactors (VHTRs). The project will lead to a coupled neutronics and thermal hydraulic (T/H) core simulation tool with fuel depletion capability. The computational tool will be developed in hexagonal geometry, based solely on transport theory without (spatial) homogenization in complicated 3D geometries. In addition to the hexagonal geometry extension, collaborators will concurrently develop three additional capabilities to increase the code’s versatility as an advanced and robust core simulator for VHTRs. First, the project team will develop and implement a depletion method within the core simulator. Second, the team will develop an elementary (proof-of-concept) 1D time-dependent transport method for efficient transient analyses. The third capability will be a thermal hydraulic method coupled to the neutronics transport module for VHTRs. Current advancements in reactor core design are pushing VHTRs toward greater core and fuel heterogeneity to pursue higher burn-ups, efficiently transmute used fuel, maximize energy production, and improve plant economics and safety. As a result, an accurate and efficient neutron transport, with capabilities to treat heterogeneous burnable poison effects, is highly desirable for predicting VHTR neutronics performance. This research project’s primary objective is to advance the state of the art for reactor analysis.
Cech, Heinz; Fuchs, Erich; Heher, Anton; Ilo, Albana; Sezi, Tevfik; Trimmel, Johann; Werner, Thomas; Marti-Rodriguez, Juan
2010-09-15
Decentralized Energy Resources (DERs) will play a significant role in future energy scenarios. Today, the 'plug and forget' connection principle for renewable energy resources has the goal to maximize the active power transfer, without using their real capabilities. Other DERs based on fossil fuels are only activated in emergency situations. This paper describes the results of a demonstration project, where DERs installed in a large distribution area are utilized for participating in the day ahead energy market, frequency and voltage support for the transmission system, voltage support at specific distribution locations and feeders, and stability support in emergency situations.
Prediction and optimization methods for electric vehicle charging schedules in the EDISON project
Aabrandt, Andreas; Andersen, Peter Bach; Pedersen, Anders Bro;
2012-01-01
project has been launched to investigate various areas relevant to electric vehicle integration. As part of EDISON an electric vehicle aggregator has been developed to demonstrate smart charging of electric vehicles. The emphasis of this paper is the mathematical methods on which the EDISON aggregator......Smart charging, where the charging of an electric vehicle battery is delayed or advanced in time based on energy costs, grid capacity or renewable contents, has a great potential for increasing the value of the electric vehicle to the owner, the grid and society as a whole. The Danish EDISON...
Ising耦合体系中量子傅里叶变换的优化%Time-optimized quantum QFT gate in an Ising coupling system
2015-01-01
Quantum Fourier transform (QFT) is a quantum analogue of the classical discrete Fourier transform. It is a fundamental quantum gate in quantum algorithms which has an exponential advantage over the classical computation and has been excessively studied. Normally, an n-qubit quantum Fourier transform could be resolved into the tensor product of n single-qubit operations, and each operation could be implemented by a Hadamard gate and a controlled phase gate. Then the complexity of an n-qubit QFT is of order O(n2). To reduce the complexity of quantum operations, optimal control (OC) method has recently been used successfully to find the minimum time for implementing a quantum operation. Up to now, two types of quantum optimal control methods have been presented, i.e. analytical and numerical methods. The analytical approach is to change the problem of eﬃcient synthesis of unitary transformations into the geometrical one of finding the shortest paths. Numerical optimal control procedures are based on the gradient methods (GRAPE, Gradient Ascent Pulse Engineering) and Krotov methods. Notable application mainly focus on nuclear magnetic resonance fields, including imaging, liquid-state NMR, solid-state NMR, and NMR quantum computation. One obvious advantage of optimal control NMR quantum computation is that the OC unitary evolution transformation pulse sequences are normally shorter than the conventional corresponding ones. Here we use the optimal control method to find the minimum duration for implementing QFT quantum gate. A linear spin chain with nearest-neighbor Ising interaction is used to find the optimization. And the optimized pulse sequence is experimentally demonstrated on an NMR quantum information processor. By using optimal control method with numerical calculation, a three-qubit QFT in an indirect-linear-coupling chain system is optimized. The duration of the OC QFT is obviously shorter than that of conventional approaches. The OC pulse sequence has been
Peterkin, Adria J.
2016-01-01
Systems Engineering is an interdisciplinary practice that analyzes different facets of a suggested area to properly develop and design an efficient system guided by the principles and restrictions of the science community. When entering an institution with quantitative and analytical scientific theory it is important to make sure that all parts of a system correlates in a structured and systematic manner so that all areas of intricacy will be prevented or quickly deduced. My research focused on interpreting and implementing Systems Engineering techniques in the construction, integration and operation of a NASA Radio Jove Kit to Observe Jupiter radio emissions. Jupiter emissions read at very low frequencies so when building the telescope it had to be able to read less than 39.5 MHz. The projected outcome was to receive long L-bursts and short S-burts signals; however, during the time of observation Jupiter was in conjunction with the Sun. We then decided to use the receiver built from the NASA Radio Jove Kit to hook it up to the Karl Jansky telescope to make an effort to listen to solar flares as well, nonetheless, we were unable to identify these signals and further realized they were noise. The overall project was a success in that we were able to apply and comprehend, the principles of Systems Engineering to facilitate the build.
Krause, David; John, Werner; Weigel, Robert
2016-03-01
The implementation of electrical drive trains in modern vehicles is a new challenge for EMC development. This contribution depicts a variety of investigations on magnetic field coupling of automotive high-voltage (HV) systems in order to fulfil the requirements of an EMR-optimized designing. The theoretical background is discussed within the scope of current analysis, including the determination of current paths and spectral behaviour. It furthermore presents models of shielded HV cables with particular focus on the magnetic shielding efficiency. Derived findings are validated by experimental measurements of a state-of-the-art demonstrator on system level. Finally EMC design rules are discussed in the context of minimized magnetic fields.
Larsen, Erik Huusfeldt
1998-01-01
. The optimized anion and cation exchange HPLC-ICP-MS systems were used for arsenic speciation in contaminated ground water and in an in-house shrimp reference sample. For the purpose of verification, HPLC coupled with tandem mass spectrometry with electrospray ionization was additionally used for arsenic....... Anion and cation exchange HPLC systems, which meet these requirements, were used for the separation of selenium and arsenic species in crude extracts of biological samples. Furthermore, the signal-to-noise ratios obtained for these incompletely ionized elements in the argon ICP were further enhanced...
DOUBLE SHELL TANK (DST) INTEGRITY PROJECT HIGH LEVEL WASTE CHEMISTRY OPTIMIZATION
WASHENFELDER DJ
2008-01-22
The U.S. Department of Energy's Office (DOE) of River Protection (ORP) has a continuing program for chemical optimization to better characterize corrosion behavior of High-Level Waste (HLW). The DOE controls the chemistry in its HLW to minimize the propensity of localized corrosion, such as pitting, and stress corrosion cracking (SCC) in nitrate-containing solutions. By improving the control of localized corrosion and SCC, the ORP can increase the life of the Double-Shell Tank (DST) carbon steel structural components and reduce overall mission costs. The carbon steel tanks at the Hanford Site are critical to the mission of safely managing stored HLW until it can be treated for disposal. The DOE has historically used additions of sodium hydroxide to retard corrosion processes in HLW tanks. This also increases the amount of waste to be treated. The reactions with carbon dioxide from the air and solid chemical species in the tank continually deplete the hydroxide ion concentration, which then requires continued additions. The DOE can reduce overall costs for caustic addition and treatment of waste, and more effectively utilize waste storage capacity by minimizing these chemical additions. Hydroxide addition is a means to control localized and stress corrosion cracking in carbon steel by providing a passive environment. The exact mechanism that causes nitrate to drive the corrosion process is not yet clear. The SCC is less of a concern in the newer stress relieved double shell tanks due to reduced residual stress. The optimization of waste chemistry will further reduce the propensity for SCC. The corrosion testing performed to optimize waste chemistry included cyclic potentiodynamic volarization studies. slow strain rate tests. and stress intensity factor/crack growth rate determinations. Laboratory experimental evidence suggests that nitrite is a highly effective:inhibitor for pitting and SCC in alkaline nitrate environments. Revision of the corrosion control
Hybrid-optimization algorithm for the management of a conjunctive-use project and well field design
Chiu, Yung-Chia; Nishikawa, Tracy; Martin, Peter
2012-01-01
Hi-Desert Water District (HDWD), the primary water-management agency in the Warren Groundwater Basin, California, plans to construct a waste water treatment plant to reduce future septic-tank effluent from reaching the groundwater system. The treated waste water will be reclaimed by recharging the groundwater basin via recharge ponds as part of a larger conjunctive-use strategy. HDWD wishes to identify the least-cost conjunctiveuse strategies for managing imported surface water, reclaimed water, and local groundwater. As formulated, the mixed-integer nonlinear programming (MINLP) groundwater-management problem seeks to minimize water delivery costs subject to constraints including potential locations of the new pumping wells, California State regulations, groundwater-level constraints, water-supply demand, available imported water, and pump/recharge capacities. In this study, a hybrid-optimization algorithm, which couples a genetic algorithm and successive-linear programming, is developed to solve the MINLP problem. The algorithm was tested by comparing results to the enumerative solution for a simplified version of the HDWD groundwater-management problem. The results indicate that the hybrid-optimization algorithm can identify the global optimum. The hybrid-optimization algorithm is then applied to solve a complex groundwater-management problem. Sensitivity analyses were also performed to assess the impact of varying the new recharge pond orientation, varying the mixing ratio of reclaimed water and pumped water, and varying the amount of imported water available. The developed conjunctive management model can provide HDWD water managers with information that will improve their ability to manage their surface water, reclaimed water, and groundwater resources.
Moonen, Dominicus Johannes Guilielmus; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes
2016-01-01
To reduce common mode(CM) and differential mode(DM) interference, a DM/CM integrated filter is often required to reduce the level of interference. This paper will show coupling from a Common Mode Choke(CMC) into Cx capacitors can decrease the DM-filtering performance significantly at high
Heat Treatment Optimization Studies on PIT Nb$_3$Sn Strand for the NED Project
Boutboul, T; den Ouden, A; Pedrini, D; Seeber, B; Volpini, G
2009-01-01
For the Next European Dipole (NED) program, a Powder-In-Tube (PIT) strand was successfully developed by SMI. This high-performance Nb3Sn strand presents a non-copper critical current density of ~ 2500 A/mm2 at 12 T applied field and 4.2 K and a filament diameter around 50 µm. Extensive heat treatment optimization studies were performed in order to maximize both critical current and RRR, with a plateau temperature down to 625 oC and duration up to 400 hours. It appears that a critical current enhancement of ~ 10 % can be achieved for a reaction schedule of 320 hours at 625 oC with non-copper critical current density respectively exceeding 2700 and 1500 A/mm2 at 12 and 15 T (4.2 K). Thanks to this modified heat treatment, this strand completely fulfils the NED stringent specification.
Zsuzsanna Kuklenyik
2015-02-01
Full Text Available In this report we demonstrate a practical multivariate design of experiment (DoE approach for asymmetric flow field-flow fractionation (AF4 method optimization using separation of lipoprotein subclasses as an example. First, with the aid of commercially available software, we built a full factorial screening design where the theoretical outcomes were calculated by applying established formulas that govern AF4 channel performance for a 5–35 nm particle size range of interest for lipid particles. Second, using the desirable ranges of instrumental parameters established from theoretical optimization, we performed fractional factorial DoE for AF4 separation of pure albumin and ferritin with UV detection to narrow the range of instrumental parameters and allow optimum size resolution while minimizing losses from membrane immobilization. Third, the optimal range of conditions were tested using response surface DoE for sub-fractionation of high and low density lipoproteins (HDL and LDL in human serum, where the recovery of the analytes were monitored by fraction collection and isotope-dilution LC-MS/MS analysis of each individual fraction for cholesterol and apolipoproteins (ApoA-1 and ApoB-100. Our results show that DoE is an effective tool in combining AF4 theoretical knowledge and experimental data in finding the most optimal set of AF4 instrumental parameters for quantitative coupling with LC-MS/MS measurements.
Sant'Ana, Flavio W; Santelli, Ricardo E; Cassella, Alessandra R; Cassella, Ricardo J
2007-10-01
This work reports the optimization of a focused microwave assisted procedure for the wet acid dissolution of diesel oil in order to allow the determination of metals in the samples by inductively coupled plasma optical emission spectrometry (ICP-OES). The dissolution process was monitored by measuring residual carbon content (RCC), also by ICP-OES, in the final solutions obtained after application of digestion program. All experimental work was performed using a commercial sample of diesel oil containing 85.74+/-0.13% of carbon. The initial dissolution program comprised three steps: (i) carbonization with H(2)SO(4); (ii) oxidation with HNO(3) and (iii) final oxidation with H(2)O(2). During work it was verified that the first step played an important role on the dissolution process of this kind of sample. It is therefore, necessary to give a detailed optimization of such step. Employing the optimized conditions it was possible to digest 2.5 g of diesel oil with a 40 min-heating program. At these conditions, residual carbon content was always lower than 5%. Optimized methodology was applied in the determination of metals in three diesel oil samples by ICP-OES. Recovery tests were also performed by adding 10 microg of metals, as organic standards, to the samples before digestion. Recovery percentages always higher than 90% were obtained for the metals of interest (Al, Cu, Fe and Ni), except for Zn, which presented recoveries between 70 and 78%.
Mangin, Antoine; Bryere, Philippe; Pastres, Roberto; Loisel, Hubert; Vincent, Chloe; Palazzo, Dalila; Brigolin, Daniele; Hembise, Odile; Arino, Olivier
2016-08-01
The SMART project (Sustainable Management of Aquaculture through Remote sensing Technology, www.smart-eo.eu), supported by ESA DUE-Innovator program, aims to use the most advanced of Earth Observation (EO) to develop coastal aquaculture services. We present here the results concerning the monitoring of natural marine conditions for operational aquaculture, the optimization of locations for farming and the mapping of potential in terms of carrying capacity for shellfish. In this context EO derived information like Sea Surface Temperature (SST), Chlorophyll-a (Chl-a) and Suspended Matters (SPM), has been validated and used as input for a growth model of mussels. Moreover, a fish cage detection methodology based on Sentinel-1 and 2 images has been developed to map out cages number and location in the western Mediterranean Sea.
Heilemann, I. [Energie Kontor Aachen, Ingenieurgesellschaft Technologie Park Herzogenrath (Germany)
1995-01-01
This article presents a museum project for a Neanderthal museum advertised in the scope of a competition. The main part of the building is under ground. With the aim of a efficient energy supply, an energy supply concept has been developed based on innovative technology: Gas driven multi-engine dual purpose power plants in parallel network operation, modular structure of the ventilation system, intelligent control technology with central direct digital control plant, constant radiation climate in the basement. This article gives a survey about the plant concept. (HW) [Deutsch] Der vorliegende Beitrag stellt ein im Rahmen eines Wettbewerbs ausgeschriebenes Museumsprojekt fuer ein Neanderthal-Museum vor. Der Hauptteil des Gebaeudes ist dabei unterirdisch angeordnet. Mit dem Ziel der rationellen Energieversorgung wurde ein Energieversorgungskonzept erstellt, das auf innovativer Technologie basiert: Gasbetriebenes Mehrmotoren-BHKW im Netzparallelbetrieb, modularer Aufbau der RLT-Anlage, intelligente Leittechnik mit zentraler DDC-Regelung, gleichmaessiges Strahlungsklima im Untergeschoss. Der vorliegende Beitrag gibt einen Ueberblick ueber das Anlagenkonzept. (HW)
Rosinski, S.T.; Nakos, J.T.
1993-09-01
Light water reactor pressure vessel (RPV) material properties reduced by long-term exposure to neutron irradiation can be recovered through a thermal annealing treatment. This technique to extend RPV life, discussed in this report, provides a complementary approach to analytical methodologies to evaluate RPV integrity. RPV annealing has been successfully demonstrated in the former Soviet Union and on a limited basis by the US (military applications only). The process of demonstrating the technical feasibility of annealing commercial US RPVs is being pursued through a cooperative effort between the nuclear industry and the US Department of Energy (USDOE) Plant Lifetime Improvement (PLIM) Program. Presently, two projects are under way through the USDOE PLIM Program to demonstrate the technical feasibility of annealing commercial US RPVS, (1) annealing re-embrittlement data base development and (2) heat transfer boundary condition experiments.
Final report on LDRD project: Simulation/optimization tools for system variability analysis
R. L. Bierbaum; R. F. Billau; J. E. Campbell; K. D. Marx; R. J. Sikorski; B. M. Thompson; S. D. Wix
1999-10-01
>This work was conducted during FY98 (Proposal Number 98-0036) and FY99 (Proposal Number 99-0818) under the auspices of the Sandia National Laboratories Laboratory-Directed Research and Development (LDRD) program. Electrical simulation typically treats a single data point in the very large input space of component properties. For electrical simulation to reach its full potential as a design tool, it must be able to address the unavoidable variability and uncertainty in component properties. Component viability is strongly related to the design margin (and reliability) of the end product. During the course of this project, both tools and methodologies were developed to enable analysis of variability in the context of electrical simulation tools. Two avenues to link relevant tools were also developed, and the resultant toolset was applied to a major component.
Jonsdottir, Svava Osk; Reffstrup, Trine Klein; Petersen, Annette
This pilot project is intended as the first step in developing a computational strategy to assist in refining methods for higher tier cumulative and aggregate risk assessment of exposure to mixture of pesticides and biocides. For this purpose, physiologically based toxicokinetic (PBTK) models were...... developed for two compounds, tebuconazole and prochloraz, and a binary mixture of these compounds in two species, rat and human. PBTK models can be used to estimate the concentration levels (internal doses) of toxic substances and their metabolites in blood and tissue, by a collection of differential...... the models. Exposure scenarios were constructed based on findings of pesticide residues in food of ordinary consumers, and assessment of dermal exposure of professional workers. PBTK simulations were carried using these scenarios....
Assareh, Ehsanolah; Poultangari, Iman [Dezful Branch, Islamic Azad University, Dezful (Iran, Islamic Republic of); Tandis, Emad [Mechanical Engineering Department, University of Jundi Shapor, Dezful (Iran, Islamic Republic of); Nedael, Mojtaba [Dept. of Energy Engineering, Graduate School of the Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)
2016-10-15
Enhancing the energy production from wind power in low-wind areas has always been a fundamental subject of research in the field of wind energy industry. In the first phase of this research, an initial investigation was performed to evaluate the potential of wind in south west of Iran. The initial results indicate that the wind potential in the studied location is not sufficient enough and therefore the investigated region is identified as a low wind speed area. In the second part of this study, an advanced optimization model was presented to regulate the torque in the wind generators. For this primary purpose, the torque of wind turbine is adjusted using a Proportional and integral (PI) control system so that at lower speeds of the wind, the power generated by generator is enhanced significantly. The proposed model uses the RBF neural network to adjust the net obtained gains of the PI controller for the purpose of acquiring the utmost electricity which is produced through the generator. Furthermore, in order to edify and instruct the neural network, the optimal data set is obtained by a Hybrid genetic algorithm along with a gravitational search algorithm (HGA-GSA). The proposed method is evaluated by using a 5MW wind turbine manufactured by National Renewable Energy Laboratory (NREL). Final results of this study are indicative of the satisfactory and successful performance of the proposed investigated model.
Stankovskiy, Evgeny Yuryevich
In the recently completed RACE Project of the AFCI, accelerator-driven subcritical systems (ADS) experiments were conducted to develop technology of coupling accelerators to nuclear reactors. In these experiments electron accelerators induced photon-neutron reactions in heavy-metal targets to initiate fission reactions in ADS. Although the Idaho State University (ISU) RACE ADS was constructed only to develop measurement techniques for advanced experiments, many reactor kinetics experiments were conducted there. In the research reported in this dissertation, a method was developed to calculate kinetics parameters for measurement and calculation of the reactivity of ADS, a safety parameter that is necessary for control and monitoring of power production. Reactivity is measured in units of fraction of delayed versus prompt neutron from fission, a quantity that cannot be directly measured in far-subcritical reactors such as the ISU RACE configuration. A new technique is reported herein to calculate it accurately and to predict kinetic behavior of a far-subcritical ADS. Experiments conducted at ISU are first described and experimental data are presented before development of the kinetic theory used in the new computational method. Because of the complexity of the ISU ADS, the Monte-Carlo method as applied in the MCNP code is most suitable for modeling reactor kinetics. However, the standard method of calculating the delayed neutron fraction produces inaccurate values. A new method was developed and used herein to evaluate actual experiments. An advantage of this method is that its efficiency is independent of the fission yield of delayed neutrons, which makes it suitable for fuel with a minor actinide component (e.g. transmutation fuels). The implementation of this method is based on a correlated sampling technique which allows the accurate evaluation of delayed and prompt neutrons. The validity of the obtained results is indicated by good agreement between experimental
谈建设项目全寿命周期成本的优化%Discussion on the entire life circle cost optimization of construction project
张胜雨
2012-01-01
This paper describes relevant identification of the entire life circle cost optimization of construction project,expounds entire life circle cost optimization method of construction project,and shows optimization steps based on mathematical model,so as to realize the economy and rationality of entire life circle of construction project.%针对建设项目全寿命周期成本优化的相关概念分别作了叙述,并对建设项目全寿命周期成本优化方法进行了详细说明,同时给出了基于数学模型的优化步骤,以实现建设项目全寿命周期的经济性和合理性。
Optimal Architecture for an Asteroid Mining Mission: System Components and Project Execution
Erickson, Ken R.
2007-01-01
Near-Earth asteroids (NEAs) offer potential profits both in the near-term (mining platinum group metals, or PGMs) and long-term (harvesting water, volatiles and ore to provide the economic backbone for lunar, Martian and other space exploration). The abundance of raw materials in NEAs include: water and other volatiles for life-support and power, nickel, iron and other metals for construction and manufacturing; carbonaceous compounds for ceramics and building materials; and PGMs for fuel cells and numerous applications on Earth. An efficient, flexible and cost-effective mission utilizing adaptable and resilient robotic compo-nents is essential to successfully establish NEA mining as a comer-cial enterprise. This paper presents an optimized architecture, detailing necessary engineering components, task integration between them, and methods to address the more likely problems encountered. Candidate NEAs are suggested that could offer optimal PGM resources and that have already been evaluated by rendezvous mapping. Mission delta-V and propellant selection are based upon launch from and return to LEO. On-site equipment includes AI-guided robotics, with human telecontrol from Earth to minimize risk and cost. A command-control-communication (CCC) unit orbits the NEA, and coordinates four small lander-miners (LMs), each of which acquire and process regolith. Two LMs are specialized for water and volatiles, two for PGM and Ni-Fe ore. A solar-powered unit hydrolyzes water from the NEA into H2 and O2 for use as propellant, and a solar-thermal propulsion unit returns additional water, PGMs and Ni-Fe ore to LEO. The pro-posed architecture emphasizes flexibility, redundancy of critical units, and fail-safes to maximize probability of mission success. Potential problems addressed include: failure of components, varying surface conditions and mineralogic content, fluctuating solar exposure (due to asteroid rotation) and its impact on solar power units, extreme temperature changes
Hambali, Nor Azura Malini A; Mahdi, Mohd Adzir; Al-Mansoori, Mohammed Hayder; Saripan, M Iqbal; Abas, Ahmad Fauzi
2009-09-20
The operation of a single-wavelength Brillouin-erbium fiber laser (BEFL) system with a Brillouin pump preamplified technique for different output coupling ratios in a ring cavity is experimentally demonstrated. The characteristics of Brillouin Stokes power and tunability were investigated in this research. The efficiency of the BEFL operation was obtained at an optimum output coupling ratio of 95%. By fixing the Brillouin pump wavelength at 1550 nm while its power was set at 1.6 mW and the 1480 pump power was set to its maximum value of 135 mW, the Brillioun Stokes power was found to be 28.7 mW. The Stokes signal can be tuned within a range of 60 nm from 1520 to 1580 nm without appearances of the self-lasing cavity modes in the laser system.
Jonathan A Hare
Full Text Available We couple a species range limit hypothesis with the output of an ensemble of general circulation models to project the poleward range limit of gray snapper. Using laboratory-derived thermal limits and statistical downscaling from IPCC AR4 general circulation models, we project that gray snapper will shift northwards; the magnitude of this shift is dependent on the magnitude of climate change. We also evaluate the uncertainty in our projection and find that statistical uncertainty associated with the experimentally-derived thermal limits is the largest contributor (∼ 65% to overall quantified uncertainty. This finding argues for more experimental work aimed at understanding and parameterizing the effects of climate change and variability on marine species.
Topology Optimization for Convection Problems
Alexandersen, Joe
2011-01-01
This report deals with the topology optimization of convection problems.That is, the aim of the project is to develop, implement and examine topology optimization of purely thermal and coupled thermomechanical problems,when the design-dependent eects of convection are taken into consideration.......This is done by the use of a self-programmed FORTRAN-code, which builds on an existing 2D-plane thermomechanical nite element code implementing during the course `41525 FEM-Heavy'. The topology optimizationfeatures have been implemented from scratch, and allows the program to optimize elastostatic mechanical...
Optimization of quantum Hamiltonian evolution: From two projection operators to local Hamiltonians
Patel, Apoorva; Priyadarsini, Anjani
Given a quantum Hamiltonian and its evolution time, the corresponding unitary evolution operator can be constructed in many different ways, corresponding to different trajectories between the desired end-points and different series expansions. A choice among these possibilities can then be made to obtain the best computational complexity and control over errors. It is shown how a construction based on Grover's algorithm scales linearly in time and logarithmically in the error bound, and is exponentially superior in error complexity to the scheme based on the straightforward application of the Lie-Trotter formula. The strategy is then extended first to simulation of any Hamiltonian that is a linear combination of two projection operators, and then to any local efficiently computable Hamiltonian. The key feature is to construct an evolution in terms of the largest possible steps instead of taking small time steps. Reflection operations and Chebyshev expansions are used to efficiently control the total error on the overall evolution, without worrying about discretization errors for individual steps. We also use a digital implementation of quantum states that makes linear algebra operations rather simple to perform.
Zhao, Ying; Lu, Wenxi; Xiao, Chuanning
2016-02-01
As the incidence frequency of groundwater pollution increases, many methods that identify source characteristics of pollutants are being developed. In this study, a simulation-optimization approach was applied to determine the duration and magnitude of pollutant sources. Such problems are time consuming because thousands of simulation models are required to run the optimization model. To address this challenge, the Kriging surrogate model was proposed to increase computational efficiency. Accuracy, time consumption, and the robustness of the Kriging model were tested on both homogenous and non-uniform media, as well as steady-state and transient flow and transport conditions. The results of three hypothetical cases demonstrate that the Kriging model has the ability to solve groundwater contaminant source problems that could occur during field site source identification problems with a high degree of accuracy and short computation times and is thus very robust.
Li, Zhihai; Li, Hui; Chen, Songjie; Froehlich, Toni; Yi, Chenyi; Schönenberger, Christian; Calame, Michel; Decurtins, Silvio; Liu, Shi-Xia; Borguet, Eric
2014-06-25
We report a novel strategy for the regulation of charge transport through single molecule junctions via the combination of external stimuli of electrode potential, internal modulation of molecular structures, and optimization of anchoring groups. We have designed redox-active benzodifuran (BDF) compounds as functional electronic units to fabricate metal-molecule-metal (m-M-m) junction devices by scanning tunneling microscopy (STM) and mechanically controllable break junctions (MCBJ). The conductance of thiol-terminated BDF can be tuned by changing the electrode potentials showing clearly an off/on/off single molecule redox switching effect. To optimize the response, a BDF molecule tailored with carbodithioate (-CS2(-)) anchoring groups was synthesized. Our studies show that replacement of thiol by carbodithioate not only enhances the junction conductance but also substantially improves the switching effect by enhancing the on/off ratio from 2.5 to 8.
Mahowald, Natalie [Cornell Univ., Ithaca, NY (United States)
2016-11-29
Soils in natural and managed ecosystems and wetlands are well known sources of methane, nitrous oxides, and reactive nitrogen gases, but the magnitudes of gas flux to the atmosphere are still poorly constrained. Thus, the reasons for the large increases in atmospheric concentrations of methane and nitrous oxide since the preindustrial time period are not well understood. The low atmospheric concentrations of methane and nitrous oxide, despite being more potent greenhouse gases than carbon dioxide, complicate empirical studies to provide explanations. In addition to climate concerns, the emissions of reactive nitrogen gases from soils are important to the changing nitrogen balance in the earth system, subject to human management, and may change substantially in the future. Thus improved modeling of the emission fluxes of these species from the land surface is important. Currently, there are emission modules for methane and some nitrogen species in the Community Earth System Model’s Community Land Model (CLM-ME/N); however, there are large uncertainties and problems in the simulations, resulting in coarse estimates. In this proposal, we seek to improve these emission modules by combining state-of-the-art process modules for emissions, available data, and new optimization methods. In earth science problems, we often have substantial data and knowledge of processes in disparate systems, and thus we need to combine data and a general process level understanding into a model for projections of future climate that are as accurate as possible. The best methodologies for optimization of parameters in earth system models are still being developed. In this proposal we will develop and apply surrogate algorithms that a) were especially developed for computationally expensive simulations like CLM-ME/N models; b) were (in the earlier surrogate optimization Stochastic RBF) demonstrated to perform very well on computationally expensive complex partial differential equations in
The DEAD-Box Protein Dhh1p Couples mRNA Decay and Translation by Monitoring Codon Optimality.
Radhakrishnan, Aditya; Chen, Ying-Hsin; Martin, Sophie; Alhusaini, Najwa; Green, Rachel; Coller, Jeff
2016-09-22
A major determinant of mRNA half-life is the codon-dependent rate of translational elongation. How the processes of translational elongation and mRNA decay communicate is unclear. Here, we establish that the DEAD-box protein Dhh1p is a sensor of codon optimality that targets an mRNA for decay. First, we find mRNAs whose translation elongation rate is slowed by inclusion of non-optimal codons are specifically degraded in a Dhh1p-dependent manner. Biochemical experiments show Dhh1p is preferentially associated with mRNAs with suboptimal codon choice. We find these effects on mRNA decay are sensitive to the number of slow-moving ribosomes on an mRNA. Moreover, we find Dhh1p overexpression leads to the accumulation of ribosomes specifically on mRNAs (and even codons) of low codon optimality. Lastly, Dhh1p physically interacts with ribosomes in vivo. Together, these data argue that Dhh1p is a sensor for ribosome speed, targeting an mRNA for repression and subsequent decay.
M. Seifouri
2013-10-01
Full Text Available In this paper, the laterally coupled distributed feedback semiconductor laser is studied. In the simulations performed, variations of structural parameters such as the grating amplitude a, the ridge width W, the thickness of the active region d, and other structural properties are considered. It is concluded that for certain values of structural parameters, the laser maintains the highest output power, the lowest distortion Bragg frequency δL and the smallest changes in the wavelength λ. Above threshold, output power more than 40mW and SMSR values greater than 50 dB were achieved.
Security Enhancement With Optimal QOS Using EAP-AKA In Hybrid Coupled 3G-WLAN Convergence Network
R Shankar; Timothy Rajkumar.K; P Dananjayan
2010-01-01
The third generation partnership project (3GPP) has addressed the feasibility of interworking and specified the interworking architecture and security architecture for third generation (3G)-wireless local area network (WLAN), it is developing, system architecture evolution (SAE)/ long term evolution (LTE) architecture, for the next generation mobile communication system. To provide a secure 3G-WLAN interworking in the SAE/LTE architecture, Extensible authentication protocol-authentication and...
Gilau, Asmerom M.
This dissertation addresses two distinct objectives; designing cost-effective renewable energy powered projects including seawater reverse osmosis (SWRO), aquaculture, and ice-making plant, and analyzing the cost-effectiveness of these projects in achieving low abatement costs and promoting sustainable developments under the Clean Development Mechanism. The results of SWRO analysis show that a wind powered system is the least expensive and a PV powered system the most expensive, with finished water costs of about 0.50 /m3 and 1.00 /m3, respectively. By international standards, these costs are competitive. The results of renewable energy powered commercial tilapia production indicate that a wind-diesel system has high potential for intensive tilapia production as well as carbon dioxide emission reductions. The study also investigates aeration failures in renewable energy powered tilapia production systems. With respect to the ice-making plant, unlike previous studies which consider nighttime operation only, we have found that a nighttime PV powered ice-making system is more expensive (1/kWh) than daytime ice-making system (0.70/kWh). Our optimal energy options analysis at project scale which includes SWRO, ice-making plant and household energy consumption for about 100 households shows that compared to diesel only energy option, PV-D, W-D, and PV-W-D hybrids are very cost-effective energy options. Moreover, energy options with high levels of renewable energy including 100% renewables have the lowest net present cost and they are already cost-effective without CDM. On the other hand, while the removal of about 87% carbon dioxide emissions could be achieved at negative cost, initial investment could increase by a factor of 40, which is one of the primary barriers hindering wider renewable energy applications in developing countries. Thus in order to increase developing countries' participation in the carbon market, CDM policy should shift from a purely market oriented
Ahmadivand, Arash; Golmohammadi, Saeed
2014-06-20
In this work, a configuration of bulk gold nanorings with certain geometrical sizes has been utilized for designing efficient photonic subwavelength nanostructures. We verify that adjacent heptamers based on gold nanorings are able to couple and transport magnetic plasmon resonance along a nanoring array in chrysene and triphenylene molecule orientations. This magnetic resonance transmission is caused by an antiphase circular current through the heptamer arrays. An orientation model of nanoring heptamers helps us to provide efficient optical structures with a remarkable decay length and a trivial ratio of destructive interferences. Exploiting the robust magnetic plasmon resonance coupling effect between heptamers arrays, we would be able to propose a practical plasmonic waveguide, a Y-shaped optical power divider (splitter), and an ON/OFF router that is operating based on destructive and constructive interferences. The quality of power splitting has been discussed comprehensively and also, the effect of undesirable occasions on the functioning performance of the proposed router has been investigated numerically. Ultimately, we verify that employing heptamers based on gold nanorings leads us to propose efficient plasmonic nanostructures and devices that are able to work in the telecommunication spectrum.
M. K. Sharbatdar
2016-11-01
Full Text Available Abstract The appropriate planning and scheduling for reaching the project goals in the most economical way is the very basic issue of the project management. As in each project, the project manager must determine the required activities for the implementation of the project and select the best option in the implementation of each of the activities, in a way that the least final cost and time of the project is achieved. Considering the number of activities and selecting options for each of the activities, usually the selection has not one unique solution, but it consists of a set of solutions that are not preferred to each other and are known as Pareto solutions. On the other hand, in some actual projects, there are activities that their implementation options depend on the implementation of the prerequisite activity and are not applicable using all the implementation options, and even in some cases the implementation or the non-implementation of some activities are also dependent on the prerequisite activity implementation. These projects can be introduced as conditional projects. Much researchs have been conducted for acquiring Pareto solution set, using different methods and algorithms, but in all the done tasks the time-cost optimization of conditional projects is not considered. Thus, in the present study the concept of conditional network is defined along with some practical examples, then an appropriate way to illustrate these networks and suitable time-cost formulation of these are presented. Finally, for some instances of conditional activity networks, conditional project time-cost optimization conducted multi-objectively using known meta-heuristic algorithms such as multi-objective genetic algorithm, multi-objective particle swarm algorithm and multi-objective charged system search algorithm.
National Aeronautics and Space Administration — Optimize the performance of Gallium Antimonide (GaSb)-based 2.05 mm lasers (previously developed under JPL’s Research and Technology Development (R&TD)...
DRAFT one year extension of the short-term national product waiver for stainless steel nuts and bolts used in pipe couplings, restraints, joints, flanges and saddles for State Revolving Fund projects.
罗剑飞; 林炜铁; 蔡小龙; 李敬源
2012-01-01
Two artificial intelligence techniques, artificial neural network and genetic algorithm, were applied to optimize the fermentation medium for improving the nitrite oxidization rate of nitrite oxidizing bacteria. Experiments were conducted with the composition of medium components obtained by genetic algorithm, and the experimental data were used to build a BP (back propagation) neural network model. The concentrations of six medium components were used as input vectors, and the nitrite oxidization rate was used as output vector of the model. The BP neural network model was used as the objective function of genetic algorithm to find the optimum medium composition for the maximum nitrite oxidization rate. The maximum nitrite oxidization rate was 0.952 g 2 NO-2-N·(g MLSS)-1·d-1 , obtained at the genetic algorithm optimized concentration of medium components (g·L-1 ): NaCl 0.58, MgSO 4 ·7H 2 O 0.14, FeSO 4 ·7H 2 O 0.141, KH 2 PO 4 0.8485, NaNO 2 2.52, and NaHCO 3 3.613. Validation experiments suggest that the experimental results are consistent with the best result predicted by the model. A scale-up experiment shows that the nitrite degraded completely after 34 h when cultured in the optimum medium, which is 10 h less than that cultured in the initial medium.
Kar, Siddhartha; Chakraborty, Sujoy; Dey, Vidyut; Ghosh, Subrata Kumar
2016-06-01
This paper investigates the application of Taguchi method with fuzzy logic for multi objective optimization of roughness parameters in electro discharge coating process of Al-6351 alloy with powder metallurgical compacted SiC/Cu tool. A Taguchi L16 orthogonal array was employed to investigate the roughness parameters by varying tool parameters like composition and compaction load and electro discharge machining parameters like pulse-on time and peak current. Crucial roughness parameters like Centre line average roughness, Average maximum height of the profile and Mean spacing of local peaks of the profile were measured on the coated specimen. The signal to noise ratios were fuzzified to optimize the roughness parameters through a single comprehensive output measure (COM). Best COM obtained with lower values of compaction load, pulse-on time and current and 30:70 (SiC:Cu) composition of tool. Analysis of variance is carried out and a significant COM model is observed with peak current yielding highest contribution followed by pulse-on time, compaction load and composition. The deposited layer is characterised by X-Ray Diffraction analysis which confirmed the presence of tool materials on the work piece surface.
Coupled Parameter Optimization of PCNN Model and Vehicle Image Segmentation%PCNN模型耦合参数的优化及车辆图像分割
杨娜; 陈后金; 李艳凤; 郝晓莉
2012-01-01
The pulse coupled neural network (PCNN) has good properties for image segmentation. While the segmentation effect significantly depends on the parameter selection of PCNN. Thus, the adaptive parameter choice is important for the PCNN application research. The coupled parameter optimization algorithm based on the coupling characteristics is proposed, which combines the neural calculation principle and characteristics of gray-scale in the image local area. First, the connection weight matrix of the PCNN model is updated in terms of the Hebb rule. Then the correlation strength factor between different regions is adaptively determined by local mean square deviation. Finally, the vehicle images are segmented by the PCNN model with optimized parameters. Compared with traditional PCNN image segmentation, the proposed method increases the coupling strength between neurons and avoids over-segmentation and under-segmentation. The segmentation quality of license plate images on the moving vehicles is improved, which lays a good foundation for the subsequent feature extraction.%脉冲耦合神经网络(PCNN)具有良好的图像分割特性,但神经网络参数的选取对分割效果有较大影响,如何自适应地选择网络参数是脉冲耦合神经网络应用研究的重要内容.本文首次从脉冲耦合神经网络的耦合特性出发,结合神经计算原理及图像局部区域的灰度特性,提出了脉冲耦合神经网络耦合参数的优化算法.首先利用Hebb学习规则对脉冲耦合神经网络模型的链接权值矩阵进行更新,然后利用图像局部区域的均方差自适应确定神经元链接强度系数,最后将优化的PCNN模型应用于运动车辆图像分割.通过耦合参数的优化,增强了神经元之间的耦合强度,与传统PCNN的车辆分割结果相比,较好地避免了过分割和欠分割现象,提高了运动车辆图像中车牌区域的分割质量,为后续车辆特征的提取奠定了良好的基础.
National Aeronautics and Space Administration — The innovative methodologies proposed in this STTR Phase 1 project will enhance Loci-STREAM which is a high performance, high fidelity simulation tool already being...
National Aeronautics and Space Administration — The innovative methodologies proposed in this STTR Phase 2 project will enhance Loci-STREAM which is a high performance, high fidelity simulation tool already being...
Tian, H; Liu, C; Gao, X D; Yao, W B
2013-03-01
Granulocyte colony-stimulating factor (G-CSF) is a cytokine widely used in cancer patients receiving high doses of chemotherapeutic drugs to prevent the chemotherapy-induced suppression of white blood cells. The production of recombinant G-CSF should be increased to meet the increasing market demand. This study aims to model and optimize the carbon source of auto-induction medium to enhance G-CSF production using artificial neural networks coupled with genetic algorithm. In this approach, artificial neural networks served as bioprocess modeling tools, and genetic algorithm (GA) was applied to optimize the established artificial neural network models. Two artificial neural network models were constructed: the back-propagation (BP) network and the radial basis function (RBF) network. The root mean square error, coefficient of determination, and standard error of prediction of the BP model were 0.0375, 0.959, and 8.49 %, respectively, whereas those of the RBF model were 0.0257, 0.980, and 5.82 %, respectively. These values indicated that the RBF model possessed higher fitness and prediction accuracy than the BP model. Under the optimized auto-induction medium, the predicted maximum G-CSF yield by the BP-GA approach was 71.66 %, whereas that by the RBF-GA approach was 75.17 %. These predicted values are in agreement with the experimental results, with 72.4 and 76.014 % for the BP-GA and RBF-GA models, respectively. These results suggest that RBF-GA is superior to BP-GA. The developed approach in this study may be helpful in modeling and optimizing other multivariable, non-linear, and time-variant bioprocesses.
Levy, Mike; Kennedy, Claire
2010-01-01
This paper considers the design and development of CALL materials with the aim of achieving an optimal mix between in-class and out-of-class learning in the context of teaching Italian at an Australian university. The authors discuss three projects in relation to the following themes: (a) conceptions of the in-class/out-of-class relationship, (b)…
David E. Rupp,
2016-05-05
The 20th century climate for the Southeastern United States and surrounding areas as simulated by global climate models used in the Coupled Model Intercomparison Project Phase 5 (CMIP5) was evaluated. A suite of statistics that characterize various aspects of the regional climate was calculated from both model simulations and observation-based datasets. CMIP5 global climate models were ranked by their ability to reproduce the observed climate. Differences in the performance of the models between regions of the United States (the Southeastern and Northwestern United States) warrant a regional-scale assessment of CMIP5 models.
Luo, Xi; Nam, Joo-Youn; Zhang, Fang; Zhang, Xiaoyuan; Liang, Peng; Huang, Xia; Logan, Bruce E
2013-07-01
Waste heat can be captured as electrical energy to drive hydrogen evolution in microbial reverse-electrodialysis electrolysis cells (MRECs) by using thermolytic solutions such as ammonium bicarbonate. To determine the optimal membrane stack configuration for efficient hydrogen production in MRECs using ammonium bicarbonate solutions, different numbers of cell pairs and stack arrangements were tested. The optimum number of cell pairs was determined to be five based on MREC performance and a desire to minimize capital costs. The stack arrangement was altered by placing an extra low concentration chamber adjacent to anode chamber to reduce ammonia crossover. This additional chamber decreased ammonia nitrogen losses into anolyte by 60%, increased the coulombic efficiency to 83%, and improved the hydrogen yield to a maximum of 3.5 mol H2/mol acetate, with an overall energy efficiency of 27%. These results improve the MREC process, making it a more efficient method for renewable hydrogen gas production.
Luo, Xi
2013-07-01
Waste heat can be captured as electrical energy to drive hydrogen evolution in microbial reverse-electrodialysis electrolysis cells (MRECs) by using thermolytic solutions such as ammonium bicarbonate. To determine the optimal membrane stack configuration for efficient hydrogen production in MRECs using ammonium bicarbonate solutions, different numbers of cell pairs and stack arrangements were tested. The optimum number of cell pairs was determined to be five based on MREC performance and a desire to minimize capital costs. The stack arrangement was altered by placing an extra low concentration chamber adjacent to anode chamber to reduce ammonia crossover. This additional chamber decreased ammonia nitrogen losses into anolyte by 60%, increased the coulombic efficiency to 83%, and improved the hydrogen yield to a maximum of 3.5mol H2/mol acetate, with an overall energy efficiency of 27%. These results improve the MREC process, making it a more efficient method for renewable hydrogen gas production. © 2013 Elsevier Ltd.
Escriva-Bou, A.; Lund, J. R.; Pulido-Velazquez, M.; Spang, E. S.; Loge, F. J.
2014-12-01
Although most freshwater resources are used in agriculture, a greater amount of energy is consumed per unit of water supply for urban areas. Therefore, efforts to reduce the carbon footprint of water in cities, including the energy embedded within household uses, can be an order of magnitude larger than for other water uses. This characteristic of urban water systems creates a promising opportunity to reduce global greenhouse gas emissions, particularly given rapidly growing urbanization worldwide. Based on a previous Water-Energy-CO2 emissions model for household water end uses, this research introduces a probabilistic two-stage optimization model considering technical and behavioral decision variables to obtain the most economical strategies to minimize household water and water-related energy bills given both water and energy price shocks. Results show that adoption rates to reduce energy intensive appliances increase significantly, resulting in an overall 20% growth in indoor water conservation if household dwellers include the energy cost of their water use. To analyze the consequences on a utility-scale, we develop an hourly water-energy model based on data from East Bay Municipal Utility District in California, including the residential consumption, obtaining that water end uses accounts for roughly 90% of total water-related energy, but the 10% that is managed by the utility is worth over 12 million annually. Once the entire end-use + utility model is completed, several demand-side management conservation strategies were simulated for the city of San Ramon. In this smaller water district, roughly 5% of total EBMUD water use, we found that the optimal household strategies can reduce total GHG emissions by 4% and utility's energy cost over 70,000/yr. Especially interesting from the utility perspective could be the "smoothing" of water use peaks by avoiding daytime irrigation that among other benefits might reduce utility energy costs by 0.5% according to our