Preliminary optimal configuration on free standing hybrid riser

Directory of Open Access Journals (Sweden)

Kyoung-Su Kim

2018-05-01

Full Text Available Free Standing Hybrid Riser (FSHR is comprised of vertical steel risers and Flexible Jumpers (FJ. They are jointly connected to a submerged Buoyancy Can (BC. There are several factors that have influence on the behavior of FSHR such as the span distance between an offshore platform and a foundation, BC up-lift force, BC submerged location and FJ length.An optimization method through a parametric study is presented. Firstly, descriptions for the overall arrangement and characteristics of FSHR are introduced. Secondly, a flowchart for optimization of FSHR is suggested. Following that, it is described how to select reasonable ranges for a parametric study and determine each of optimal configuration options. Lastly, numerical analysis based on this procedure is performed through a case study. In conclusion, the relation among those parameters is analyzed and non-dimensional parametric ranges on optimal arrangements are suggested. Additionally, strength analysis is performed with variation in the configuration. Keywords: Free standing hybrid riser, Hybrid riser system, Buoyancy can, Flexible jumper, Deepwater, Multi-body dynamics

Monte Carlo Optimization of Crystal Configuration for Pixelated Molecular SPECT Scanners

Energy Technology Data Exchange (ETDEWEB)

Mahani, Hojjat [Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Research Center for Molecular and Cellular Imaging, Tehran University of Medical Science, Tehran (Iran, Islamic Republic of); Raisali, Gholamreza [Radiation Application Research School, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Kamali-Asl, Alireza [Radiation Medicine Department, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Ay, Mohammad Reza, E-mail: mohammadreza_ay@sina.tums.ac.ir [Research Center for Molecular and Cellular Imaging, Tehran University of Medical Science, Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Science, Tehran (Iran, Islamic Republic of)

2017-02-01

Resolution-sensitivity-PDA tradeoff is the most challenging problem in design and optimization of pixelated preclinical SPECT scanners. In this work, we addressed such a challenge from a crystal point-of-view by looking for an optimal pixelated scintillator using GATE Monte Carlo simulation. Various crystal configurations have been investigated and the influence of different pixel sizes, pixel gaps, and three scintillators on tomographic resolution, sensitivity, and PDA of the camera were evaluated. The crystal configuration was then optimized using two objective functions: the weighted-sum and the figure-of-merit methods. The CsI(Na) reveals the highest sensitivity of the order of 43.47 cps/MBq in comparison to the NaI(Tl) and the YAP(Ce), for a 1.5×1.5 mm{sup 2} pixel size and 0.1 mm gap. The results show that the spatial resolution, in terms of FWHM, improves from 3.38 to 2.21 mm while the sensitivity simultaneously deteriorates from 42.39 cps/MBq to 27.81 cps/MBq when pixel size varies from 2×2 mm{sup 2} to 0.5×0.5 mm{sup 2} for a 0.2 mm gap, respectively. The PDA worsens from 0.91 to 0.42 when pixel size decreases from 0.5×0.5 mm{sup 2} to 1×1 mm{sup 2} for a 0.2 mm gap at 15° incident-angle. The two objective functions agree that the 1.5×1.5 mm{sup 2} pixel size and 0.1 mm Epoxy gap CsI(Na) configuration provides the best compromise for small-animal imaging, using the HiReSPECT scanner. Our study highlights that crystal configuration can significantly affect the performance of the camera, and thereby Monte Carlo optimization of pixelated detectors is mandatory in order to achieve an optimal quality tomogram. - Highlights: • We optimized pixelated crystal configuration for the purpose of molecular SPECT imaging. • The weighted-sum and the figure-of-merit methods were used in order to search for an optimal crystal configuration. • The higher the pixel size, the poorer the resolution and simultaneously the higher the sensitivity and the PDA. • The

Monte Carlo Optimization of Crystal Configuration for Pixelated Molecular SPECT Scanners

International Nuclear Information System (INIS)

Mahani, Hojjat; Raisali, Gholamreza; Kamali-Asl, Alireza; Ay, Mohammad Reza

2017-01-01

Resolution-sensitivity-PDA tradeoff is the most challenging problem in design and optimization of pixelated preclinical SPECT scanners. In this work, we addressed such a challenge from a crystal point-of-view by looking for an optimal pixelated scintillator using GATE Monte Carlo simulation. Various crystal configurations have been investigated and the influence of different pixel sizes, pixel gaps, and three scintillators on tomographic resolution, sensitivity, and PDA of the camera were evaluated. The crystal configuration was then optimized using two objective functions: the weighted-sum and the figure-of-merit methods. The CsI(Na) reveals the highest sensitivity of the order of 43.47 cps/MBq in comparison to the NaI(Tl) and the YAP(Ce), for a 1.5×1.5 mm"2 pixel size and 0.1 mm gap. The results show that the spatial resolution, in terms of FWHM, improves from 3.38 to 2.21 mm while the sensitivity simultaneously deteriorates from 42.39 cps/MBq to 27.81 cps/MBq when pixel size varies from 2×2 mm"2 to 0.5×0.5 mm"2 for a 0.2 mm gap, respectively. The PDA worsens from 0.91 to 0.42 when pixel size decreases from 0.5×0.5 mm"2 to 1×1 mm"2 for a 0.2 mm gap at 15° incident-angle. The two objective functions agree that the 1.5×1.5 mm"2 pixel size and 0.1 mm Epoxy gap CsI(Na) configuration provides the best compromise for small-animal imaging, using the HiReSPECT scanner. Our study highlights that crystal configuration can significantly affect the performance of the camera, and thereby Monte Carlo optimization of pixelated detectors is mandatory in order to achieve an optimal quality tomogram. - Highlights: • We optimized pixelated crystal configuration for the purpose of molecular SPECT imaging. • The weighted-sum and the figure-of-merit methods were used in order to search for an optimal crystal configuration. • The higher the pixel size, the poorer the resolution and simultaneously the higher the sensitivity and the PDA. • The higher the pixel gap, the

Sequential Bayesian geoacoustic inversion for mobile and compact source-receiver configuration.

Science.gov (United States)

Carrière, Olivier; Hermand, Jean-Pierre

2012-04-01

Geoacoustic characterization of wide areas through inversion requires easily deployable configurations including free-drifting platforms, underwater gliders and autonomous vehicles, typically performing repeated transmissions during their course. In this paper, the inverse problem is formulated as sequential Bayesian filtering to take advantage of repeated transmission measurements. Nonlinear Kalman filters implement a random-walk model for geometry and environment and an acoustic propagation code in the measurement model. Data from MREA/BP07 sea trials are tested consisting of multitone and frequency-modulated signals (bands: 0.25-0.8 and 0.8-1.6 kHz) received on a shallow vertical array of four hydrophones 5-m spaced drifting over 0.7-1.6 km range. Space- and time-coherent processing are applied to the respective signal types. Kalman filter outputs are compared to a sequence of global optimizations performed independently on each received signal. For both signal types, the sequential approach is more accurate but also more efficient. Due to frequency diversity, the processing of modulated signals produces a more stable tracking. Although an extended Kalman filter provides comparable estimates of the tracked parameters, the ensemble Kalman filter is necessary to properly assess uncertainty. In spite of mild range dependence and simplified bottom model, all tracked geoacoustic parameters are consistent with high-resolution seismic profiling, core logging P-wave velocity, and previous inversion results with fixed geometries.

Improved Performance and Quality of Configurators by Receiving Real-Time Information from Suppliers

DEFF Research Database (Denmark)

Kristjansdottir, Katrin; Shafiee, Sara; Bonev, Martin

with including suppliers’ product specifications as sub-models and how these can be addressed by integrating configurators across supply chains to receive real-time information from suppliers. Based on established literature on the illustrated technical integration of configurators across the supply chains......Companies providing customized products are increasingly applying configurators in order to support the sales and design activities. Yet, especially for engineer-to-order (ETO) companies such activities are often divided across different organizations, where throughout the configuration process...... product specification has to be retrieved across the supply chains. Therefore, it is required that relevant information from suppliers is included in the configuration process, either as sub-models or by integrating configurators across the supply chains. This study investigates the challenges associated...

A parallel optimization method for product configuration and supplier selection based on interval

Science.gov (United States)

Zheng, Jian; Zhang, Meng; Li, Guoxi

2017-06-01

In the process of design and manufacturing, product configuration is an important way of product development, and supplier selection is an essential component of supply chain management. To reduce the risk of procurement and maximize the profits of enterprises, this study proposes to combine the product configuration and supplier selection, and express the multiple uncertainties as interval numbers. An integrated optimization model of interval product configuration and supplier selection was established, and NSGA-II was put forward to locate the Pareto-optimal solutions to the interval multiobjective optimization model.

Cooperative scattering of scalar waves by optimized configurations of point scatterers

Science.gov (United States)

Schäfer, Frank; Eckert, Felix; Wellens, Thomas

2017-12-01

We investigate multiple scattering of scalar waves by an ensemble of N resonant point scatterers in three dimensions. For up to N = 21 scatterers, we numerically optimize the positions of the individual scatterers, to maximize the total scattering cross section for an incoming plane wave, on the one hand, and to minimize the decay rate associated to a long-lived scattering resonance, on the other. In both cases, the optimum is achieved by configurations where all scatterers are placed on a line parallel to the direction of the incoming plane wave. The associated maximal scattering cross section increases quadratically with the number of scatterers for large N, whereas the minimal decay rate—which is realized by configurations that are not the same as those that maximize the scattering cross section—decreases exponentially as a function of N. Finally, we also analyze the stability of our optimized configurations with respect to small random displacements of the scatterers. These results demonstrate that optimized configurations of scatterers bear a considerable potential for applications such as quantum memories or mirrors consisting of only a few atoms.

Optimal resonance configuration for ultrasonic wireless power transmission to millimeter-sized biomedical implants.

Science.gov (United States)

Miao Meng; Kiani, Mehdi

2016-08-01

In order to achieve efficient wireless power transmission (WPT) to biomedical implants with millimeter (mm) dimensions, ultrasonic WPT links have recently been proposed. Operating both transmitter (Tx) and receiver (Rx) ultrasonic transducers at their resonance frequency (fr) is key in improving power transmission efficiency (PTE). In this paper, different resonance configurations for Tx and Rx transducers, including series and parallel resonance, have been studied to help the designers of ultrasonic WPT links to choose the optimal resonance configuration for Tx and Rx that maximizes PTE. The geometries for disk-shaped transducers of four different sets of links, operating at series-series, series-parallel, parallel-series, and parallel-parallel resonance configurations in Tx and Rx, have been found through finite-element method (FEM) simulation tools for operation at fr of 1.4 MHz. Our simulation results suggest that operating the Tx transducer with parallel resonance increases PTE, while the resonance configuration of the mm-sized Rx transducer highly depends on the load resistance, Rl. For applications that involve large Rl in the order of tens of kΩ, a parallel resonance for a mm-sized Rx leads to higher PTE, while series resonance is preferred for Rl in the order of several kΩ and below.

Configuration Management Plan for Long Length Contaminated Equipment Receiver and Transport Trailers

International Nuclear Information System (INIS)

DALE, R.N.

2000-01-01

Long Length Contaminated Equipment Removal System Receiver Trailer and Transport Trailer require a configuration management plan for design, requirements and operations baseline documents. This report serves as the plan for the Trailers

Aerodynamic Optimization of an Over-the-Wing-Nacelle-Mount Configuration

OpenAIRE

Sasaki, Daisuke; Nakahashi, Kazuhiro

2011-01-01

An over-the-wing-nacelle-mount airplane configuration is known to prevent the noise propagation from jet engines toward ground. However, the configuration is assumed to have low aerodynamic efficiency due to the aerodynamic interference effect between a wing and a nacelle. In this paper, aerodynamic design optimization is conducted to improve aerodynamic efficiency to be equivalent to conventional under-the-wing-nacelle-mount configuration. The nacelle and wing geometry are modified to achiev...

OPTIMAL CONFIGURATION OF A COMMAND AND CONTROL NETWORK: BALANCING PERFORMANCE AND RECONFIGURATION CONSTRAINTS

Energy Technology Data Exchange (ETDEWEB)

L. DOWELL

1999-07-01

The optimization of the configuration of communications and control networks is important for assuring the reliability and performance of the networks. This paper presents techniques for determining the optimal configuration for such a network in the presence of communication and connectivity constraints.

SOLVING OPTIMAL ASSEMBLY LINE CONFIGURATION TASK BY MULTIOBJECTIVE DECISION MAKING METHODS

Directory of Open Access Journals (Sweden)

Ján ČABALA

2017-06-01

Full Text Available This paper deals with looking for the optimal configuration of automated assembly line model placed within Department of Cybernetics and Artificial Intelligence (DCAI. In order to solve this problem, Stateflow model of each configuration was created to simulate the behaviour of particular assembly line configuration. Outputs from these models were used as inputs into the multiobjective decision making process. Multi-objective decision-making methods were subsequently used to find the optimal configuration of assembly line. Paper describes the whole process of solving this task, from building the models to choosing the best configuration. Specifically, the problem was resolved using the experts’ evaluation method for evaluating the weights of every decision-making criterion, while the ELECTRE III, TOPSIS and AGREPREF methods were used for ordering the possible solutions from the most to the least suitable alternative. Obtained results were compared and final solution of this multi-objective decisionmaking problem is chosen.

Multi-parameter optimization design of parabolic trough solar receiver

International Nuclear Information System (INIS)

Guo, Jiangfeng; Huai, Xiulan

2016-01-01

Highlights: • The optimal condition can be obtained by multi-parameter optimization. • Exergy and thermal efficiencies are employed as objective function. • Exergy efficiency increases at the expense of heat losses. • The heat obtained by working fluid increases as thermal efficiency grows. - Abstract: The design parameters of parabolic trough solar receiver are interrelated and interact with one another, so the optimal performance of solar receiver cannot be obtained by the convectional single-parameter optimization. To overcome the shortcoming of single-parameter optimization, a multi-parameter optimization of parabolic trough solar receiver is employed based on genetic algorithm in the present work. When the thermal efficiency is taken as the objective function, the heat obtained by working fluid increases while the average temperature of working fluid and wall temperatures of solar receiver decrease. The average temperature of working fluid and the wall temperatures of solar receiver increase while the heat obtained by working fluid decreases generally by taking the exergy efficiency as an objective function. Assuming that the solar radiation intensity remains constant, the exergy obtained by working fluid increases by taking exergy efficiency as the objective function, which comes at the expense of heat losses of solar receiver.

OPTIMAL CONFIGURATION OF A COMMAND AND CONTROL NETWORK: BALANCING PERFORMANCE AND RECONFIGURATION CONSTRAINTS

Energy Technology Data Exchange (ETDEWEB)

L. DOWELL

1999-08-01

The optimization of the configuration of communications and control networks is important for assuring the reliability and performance of the networks. This paper presents techniques for determining the optimal configuration for such a network in the presence of communication and connectivity constraints. reconfiguration to restore connectivity to a data-fusion network following the failure of a network component.

High-Fidelity Multidisciplinary Design Optimization of Aircraft Configurations

Science.gov (United States)

Martins, Joaquim R. R. A.; Kenway, Gaetan K. W.; Burdette, David; Jonsson, Eirikur; Kennedy, Graeme J.

2017-01-01

To evaluate new airframe technologies we need design tools based on high-fidelity models that consider multidisciplinary interactions early in the design process. The overarching goal of this NRA is to develop tools that enable high-fidelity multidisciplinary design optimization of aircraft configurations, and to apply these tools to the design of high aspect ratio flexible wings. We develop a geometry engine that is capable of quickly generating conventional and unconventional aircraft configurations including the internal structure. This geometry engine features adjoint derivative computation for efficient gradient-based optimization. We also added overset capability to a computational fluid dynamics solver, complete with an adjoint implementation and semiautomatic mesh generation. We also developed an approach to constraining buffet and started the development of an approach for constraining utter. On the applications side, we developed a new common high-fidelity model for aeroelastic studies of high aspect ratio wings. We performed optimal design trade-o s between fuel burn and aircraft weight for metal, conventional composite, and carbon nanotube composite wings. We also assessed a continuous morphing trailing edge technology applied to high aspect ratio wings. This research resulted in the publication of 26 manuscripts so far, and the developed methodologies were used in two other NRAs. 1

The ergonomics of wheelchair configuration for optimal performance in the wheelchair court sports.

Science.gov (United States)

Mason, Barry S; van der Woude, Lucas H V; Goosey-Tolfrey, Victoria L

2013-01-01

Optimizing mobility performance in wheelchair court sports (basketball, rugby and tennis) is dependent on a combination of factors associated with the user, the wheelchair and the interfacing between the two. Substantial research has been attributed to the wheelchair athlete yet very little has focused on the role of the wheelchair and the wheelchair-user combination. This article aims to review relevant scientific literature that has investigated the effects of wheelchair configuration on aspects of mobility performance from an ergonomics perspective. Optimizing performance from an ergonomics perspective requires a multidisciplinary approach. This has resulted in laboratory-based investigations incorporating a combination of physiological and biomechanical analyses to assess the efficiency, health/safety and comfort of various wheelchair configurations. To a lesser extent, field-based testing has also been incorporated to determine the effects of wheelchair configuration on aspects of mobility performance specific to the wheelchair court sports. The available literature has demonstrated that areas of seat positioning, rear wheel camber, wheel size and hand-rim configurations can all influence the ergonomics of wheelchair performance. Certain configurations have been found to elevate the physiological demand of wheelchair propulsion, others have been associated with an increased risk of injury and some have demonstrated favourable performance on court. A consideration of all these factors is required to identify optimal wheelchair configurations. Unfortunately, a wide variety of different methodologies have immerged between studies, many of which are accompanied by limitations, thus making the identification of optimal configurations problematic. When investigating an area of wheelchair configuration, many studies have failed to adequately standardize other areas, which has prevented reliable cause and effect relationships being established. In addition, a large

Optimal configuration assessment of renewable energy in Malaysia

Energy Technology Data Exchange (ETDEWEB)

Haidar, Ahmed M.A.; John, Priscilla N.; Shawal, Mohd [Faculty of Electrical and Electronics Engineering, University Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia)

2011-02-15

This paper proposes the use of a PV-wind-diesel generator hybrid system in order to determine the optimal configuration of renewable energy in Malaysia and to compare the production cost of solar and wind power with its annual yield relevant to different regions in Malaysia namely, Johor, Sarawak, Penang and Selangor. The configuration of optimal hybrid system is selected based on the best components and sizing with appropriate operating strategy to provide a cheap, efficient, reliable and cost-effective system. The various renewable energy sources and their applicability in terms of cost and performance are analyzed. Moreover, the annual yield and cost of energy production of solar and wind energy are evaluated. The Simulations were carried out using the HOMER program based on data obtained from the Malaysian Meteorological Centre. Results show that, for Malaysia, a PV-diesel generator hybrid system is the most suitable solution in terms of economic performance and pollution. However, the cost of production of solar and wind energy proved to be cheaper and more environmentally friendly than the energy produced from diesel generators. (author)

The Optimal Configuration Scheme of the Virtual Power Plant Considering Benefits and Risks of Investors

Directory of Open Access Journals (Sweden)

Jingmin Wang

2017-07-01

Full Text Available A virtual power plant (VPP is a special virtual unit that integrates various distributed energy resources (DERs distributed in the generation and consumption sides. The optimal configuration scheme of the VPP needs to break the geographical restrictions to make full use of DERs, considering the uncertainties. First, the components of the DERs and the structure of the VPP are briefly introduced. Next, the cubic exponential smoothing method is adopted to predict the VPP load requirement. Finally, the optimal configuration of the DER capacities inside the VPP is calculated by using portfolio theory and genetic algorithms (GA. The results show that the configuration scheme can optimize the DER capacities considering uncertainties, guaranteeing economic benefits of investors, and fully utilizing the DERs. Therefore, this paper provides a feasible reference for the optimal configuration scheme of the VPP from the perspective of investors.

ASTRID© - Advanced Solar Tubular ReceIver Design: A powerful tool for receiver design and optimization

Science.gov (United States)

Frantz, Cathy; Fritsch, Andreas; Uhlig, Ralf

2017-06-01

In solar tower power plants the receiver is one of the critical components. It converts the solar radiation into heat and must withstand high heat flux densities and high daily or even hourly gradients (due to passage of clouds). For this reason, the challenge during receiver design is to find a reasonable compromise between receiver efficiency, reliability, lifetime and cost. There is a strong interaction between the heliostat field, the receiver and the heat transfer fluid. Therefore, a proper receiver design needs to consider these components within the receiver optimization. There are several design and optimization tools for receivers, but most of them focus only on the receiver, ignoring the heliostat field and other parts of the plant. During the last years DLR developed the ASTRIDcode for tubular receiver concept simulation. The code comprises both a high and a low-detail model. The low-detail model utilizes a number of simplifications which allow the user to screen a high number of receiver concepts for optimization purposes. The high-detail model uses a FE model and is able to compute local absorber and salt temperatures with high accuracy. One key strength of the ASTRIDcode is its interface to a ray tracing software which simulates a realistic heat flux distributions on the receiver surface. The results generated by the ASTRIDcode have been validated by CFD simulations and measurement data.

District Heating Network Design and Configuration Optimization with Genetic Algorithm

DEFF Research Database (Denmark)

Li, Hongwei; Svendsen, Svend

2011-01-01

In this paper, the configuration of a district heating (DH) network which connects from the heating plant to the end users was optimized with emphasizing the network thermal performance. Each end user in the network represents a building block. The locations of the building blocks are fixed while...... the heating plant location is allowed to vary. The connection between the heat generation plant and the end users can be represented with mixed integer and the pipe friction and heat loss formulations are non-linear. In order to find the optimal DH distribution pipeline configuration, the genetic algorithm...... by multi factors as the consumer heating load, the distance between the heating plant to the consumer, the design criteria regarding pressure and temperature limitation, as well as the corresponding network heat loss....

A knowledge-based system for optimization of fuel reload configurations

International Nuclear Information System (INIS)

Galperin, A.; Kimhi, S.; Segev, M.

1989-01-01

The authors discuss a knowledge-based production system developed for generating optimal fuel reload configurations. The system was based on a heuristic search method and implemented in Common Lisp programming language. The knowledge base embodied the reactor physics, reactor operations, and a general approach to fuel management strategy. The data base included a description of the physical system involved, i.e., the core geometry and fuel storage. The fifth cycle of the Three Mile Island Unit 1 pressurized water reactor was chosen as a test case. Application of the system to the test case revealed a self-learning process by which a relatively large number of near-optimal configurations were discovered. Several selected solutions were subjected to detailed analysis and demonstrated excellent performance. To summarize, applicability of the proposed heuristic search method in the domain of nuclear fuel management was proved unequivocally

Optimization of line configuration and balancing for flexible machining lines

Science.gov (United States)

Liu, Xuemei; Li, Aiping; Chen, Zurui

2016-05-01

Line configuration and balancing is to select the type of line and allot a given set of operations as well as machines to a sequence of workstations to realize high-efficiency production. Most of the current researches for machining line configuration and balancing problems are related to dedicated transfer lines with dedicated machine workstations. With growing trends towards great product variety and fluctuations in market demand, dedicated transfer lines are being replaced with flexible machining line composed of identical CNC machines. This paper deals with the line configuration and balancing problem for flexible machining lines. The objective is to assign operations to workstations and find the sequence of execution, specify the number of machines in each workstation while minimizing the line cycle time and total number of machines. This problem is subject to precedence, clustering, accessibility and capacity constraints among the features, operations, setups and workstations. The mathematical model and heuristic algorithm based on feature group strategy and polychromatic sets theory are presented to find an optimal solution. The feature group strategy and polychromatic sets theory are used to establish constraint model. A heuristic operations sequencing and assignment algorithm is given. An industrial case study is carried out, and multiple optimal solutions in different line configurations are obtained. The case studying results show that the solutions with shorter cycle time and higher line balancing rate demonstrate the feasibility and effectiveness of the proposed algorithm. This research proposes a heuristic line configuration and balancing algorithm based on feature group strategy and polychromatic sets theory which is able to provide better solutions while achieving an improvement in computing time.

Optimal Switch Configuration in Software-Defined Networks

Directory of Open Access Journals (Sweden)

Béla GENGE

2016-06-01

Full Text Available The emerging Software-Defined Networks (SDN paradigm facilitates innovative applications and enables the seamless provisioning of resilient communications. Nevertheless, the installation of communication flows in SDN requires careful planning in order to avoid configuration errors and to fulfill communication requirements. In this paper we propose an approach that installs automatically and optimally static flows in SDN switches. The approach aims to select high capacity links and shortest path routing, and enforces communication link and switch capacity limitations. Experimental results demonstrate the effectiveness and scalability of the developed methodology.

Optimal conductive constructal configurations with “parallel design”

International Nuclear Information System (INIS)

Eslami, M.

2016-01-01

Highlights: • A new parallel design is proposed for conductive cooling of heat generating rectangles. • The geometric features are optimized analytically. • The internal structure morph as a function of available conductive material. • Thermal performance is superior to the previously numerically optimized designs. - Abstract: Today, conductive volume to point cooling of heat generating bodies is under investigation as an alternative method for thermal management of electronic chipsets with high power density. In this paper, a new simple geometry called “parallel design” is proposed for effective conductive cooling of rectangular heat generating bodies. This configuration tries to minimize the thermal resistance associated with the temperature drop inside the heat generating volume. The geometric features of the design are all optimized analytically and expressed with simple explicit equations. It is proved that optimal number of parallel links is equal to the thermal conductivity ratio multiplied by the porosity (or the volume ratio). With the universal aspect ratio of H/L = 2, total thermal resistance of the present parallel design is lower than the recently proposed networks of various shapes that are optimized with help of numerical simulations; especially when more conducting material is available.

Optimized combination model and algorithm of parking guidance information configuration

Directory of Open Access Journals (Sweden)

Tian Ye

2011-01-01

Full Text Available Abstract Operators of parking guidance and information (PGI systems often have difficulty in providing the best car park availability information to drivers in periods of high demand. A new PGI configuration model based on the optimized combination method was proposed by analyzing of parking choice behavior. This article first describes a parking choice behavioral model incorporating drivers perceptions of waiting times at car parks based on PGI signs. This model was used to predict the influence of PGI signs on the overall performance of the traffic system. Then relationships were developed for estimating the arrival rates at car parks based on driver characteristics, car park attributes as well as the car park availability information displayed on PGI signs. A mathematical program was formulated to determine the optimal display PGI sign configuration to minimize total travel time. A genetic algorithm was used to identify solutions that significantly reduced queue lengths and total travel time compared with existing practices. These procedures were applied to an existing PGI system operating in Deqing Town and Xiuning City. Significant reductions in total travel time of parking vehicles with PGI being configured. This would reduce traffic congestion and lead to various environmental benefits.

Optimization study for the experimental configuration of CMB-S4

Science.gov (United States)

Barron, Darcy; Chinone, Yuji; Kusaka, Akito; Borril, Julian; Errard, Josquin; Feeney, Stephen; Ferraro, Simone; Keskitalo, Reijo; Lee, Adrian T.; Roe, Natalie A.; Sherwin, Blake D.; Suzuki, Aritoki

2018-02-01

The CMB Stage 4 (CMB-S4) experiment is a next-generation, ground-based experiment that will measure the cosmic microwave background (CMB) polarization to unprecedented accuracy, probing the signature of inflation, the nature of cosmic neutrinos, relativistic thermal relics in the early universe, and the evolution of the universe. CMB-S4 will consist of O(500,000) photon-noise-limited detectors that cover a wide range of angular scales in order to probe the cosmological signatures from both the early and late universe. It will measure a wide range of microwave frequencies to cleanly separate the CMB signals from galactic and extra-galactic foregrounds. To advance the progress towards designing the instrument for CMB-S4, we have established a framework to optimize the instrumental configuration to maximize its scientific output. The framework combines cost and instrumental models with a cosmology forecasting tool, and evaluates the scientific sensitivity as a function of various instrumental parameters. The cost model also allows us to perform the analysis under a fixed-cost constraint, optimizing for the scientific output of the experiment given finite resources. In this paper, we report our first results from this framework, using simplified instrumental and cost models. We have primarily studied two classes of instrumental configurations: arrays of large-aperture telescopes with diameters ranging from 2–10 m, and hybrid arrays that combine small-aperture telescopes (0.5-m diameter) with large-aperture telescopes. We explore performance as a function of telescope aperture size, distribution of the detectors into different microwave frequencies, survey strategy and survey area, low-frequency noise performance, and balance between small and large aperture telescopes for hybrid configurations. Both types of configurations must cover both large (~ degree) and small (~ arcmin) angular scales, and the performance depends on assumptions for performance vs. angular scale

Scientific visualization of 3-dimensional optimized stellarator configurations

International Nuclear Information System (INIS)

Spong, D.A.

1998-01-01

The design techniques and physics analysis of modern stellarator configurations for magnetic fusion research rely heavily on high performance computing and simulation. Stellarators, which are fundamentally 3-dimensional in nature, offer significantly more design flexibility than more symmetric devices such as the tokamak. By varying the outer boundary shape of the plasma, a variety of physics features, such as transport, stability, and heating efficiency can be optimized. Scientific visualization techniques are an important adjunct to this effort as they provide a necessary ergonomic link between the numerical results and the intuition of the human researcher. The authors have developed a variety of visualization techniques for stellarators which both facilitate the design optimization process and allow the physics simulations to be more readily understood

The optimal configuration of photovoltaic module arrays based on adaptive switching controls

International Nuclear Information System (INIS)

Chao, Kuei-Hsiang; Lai, Pei-Lun; Liao, Bo-Jyun

2015-01-01

Highlights: • We propose a strategy for determining the optimal configuration of a PV array. • The proposed strategy was based on particle swarm optimization (PSO) method. • It can identify the optimal module array connection scheme in the event of shading. • It can also find the optimal connection of a PV array even in module malfunctions. - Abstract: This study proposes a strategy for determining the optimal configuration of photovoltaic (PV) module arrays in shading or malfunction conditions. This strategy was based on particle swarm optimization (PSO). If shading or malfunctions of the photovoltaic module array occur, the module array immediately undergoes adaptive reconfiguration to increase the power output of the PV power generation system. First, the maximal power generated at various irradiation levels and temperatures was recorded during normal array operation. Subsequently, the irradiation level and module temperature, regardless of operating conditions, were used to recall the maximal power previously recorded. This previous maximum was compared with the maximal power value obtained using the maximum power point tracker to assess whether the PV module array was experiencing shading or malfunctions. After determining that the array was experiencing shading or malfunctions, PSO was used to identify the optimal module array connection scheme in abnormal conditions, and connection switches were used to implement optimal array reconfiguration. Finally, experiments were conducted to assess the strategy for identifying the optimal reconfiguration of a PV module array in the event of shading or malfunctions

Joint Transmitter-Receiver Optimization in the Downlink CDMA Systems

Directory of Open Access Journals (Sweden)

Mohammad Saquib

2002-08-01

Full Text Available To maximize the downlink code-division multiple access (CDMA system capacity, we propose to minimize the total transmitted power of the system subject to users′ signal-to-interference ratio (SIR requirements via designing optimum transmitter sequences and utilizing linear optimum receivers (minimum mean square error (MMSE receiver. In our work on joint transmitter-receiver design for the downlink CDMA systems with multiple antennas and multipath channels, we develop several optimization algorithms by considering various system constraints and prove their convergence. We empirically observed that under the optimization algorithm with no constraint on the system, the optimum receiver structure matches the received transmitter sequences. A simulation study is performed to see how the different practical system constraints penalize the system with respect to the optimum algorithm with no constraint on the system.

Probing optimal measurement configuration for optical scatterometry by the multi-objective genetic algorithm

Science.gov (United States)

Chen, Xiuguo; Gu, Honggang; Jiang, Hao; Zhang, Chuanwei; Liu, Shiyuan

2018-04-01

Measurement configuration optimization (MCO) is a ubiquitous and important issue in optical scatterometry, whose aim is to probe the optimal combination of measurement conditions, such as wavelength, incidence angle, azimuthal angle, and/or polarization directions, to achieve a higher measurement precision for a given measuring instrument. In this paper, the MCO problem is investigated and formulated as a multi-objective optimization problem, which is then solved by the multi-objective genetic algorithm (MOGA). The case study on the Mueller matrix scatterometry for the measurement of a Si grating verifies the feasibility of the MOGA in handling the MCO problem in optical scatterometry by making a comparison with the Monte Carlo simulations. Experiments performed at the achieved optimal measurement configuration also show good agreement between the measured and calculated best-fit Mueller matrix spectra. The proposed MCO method based on MOGA is expected to provide a more general and practical means to solve the MCO problem in the state-of-the-art optical scatterometry.

Aerodynamic Shape Optimization Design of Wing-Body Configuration Using a Hybrid FFD-RBF Parameterization Approach

Science.gov (United States)

Liu, Yuefeng; Duan, Zhuoyi; Chen, Song

2017-10-01

Aerodynamic shape optimization design aiming at improving the efficiency of an aircraft has always been a challenging task, especially when the configuration is complex. In this paper, a hybrid FFD-RBF surface parameterization approach has been proposed for designing a civil transport wing-body configuration. This approach is simple and efficient, with the FFD technique used for parameterizing the wing shape and the RBF interpolation approach used for handling the wing body junction part updating. Furthermore, combined with Cuckoo Search algorithm and Kriging surrogate model with expected improvement adaptive sampling criterion, an aerodynamic shape optimization design system has been established. Finally, the aerodynamic shape optimization design on DLR F4 wing-body configuration has been carried out as a study case, and the result has shown that the approach proposed in this paper is of good effectiveness.

Application of an optimized winglet configuration to an advanced commercial transport

Science.gov (United States)

Shollenberger, C. A.

1979-01-01

The design is presented of an aircraft which employs an integrated wing and winglet lift system. Comparison was made with a conventional baseline configuration employing a high-aspect-ratio supercritical wing. An optimized wing-winglet combination was selected from four proposed configurations for which aerodynamic, structural, and weight characteristics were evaluated. Each candidate wing-winglet configuration was constrained to the same induced drag coefficient as the baseline aircraft. The selected wing-winglet configuration was resized for a specific medium-range mission requirement, and operating costs were estimated for a typical mission. Study results indicated that the wing-winglet aircraft was lighter and could complete the specified mission at less cost than the conventional wing aircraft. These indications were sensitive to the impact of flutter characteristics and, to a lesser extent, to the performance of the high-lift system. Further study in these areas is recommended to reduce uncertainty in future development.

[Optimization of electrode configuration in soil electrokinetic remediation].

Science.gov (United States)

Liu, Fang; Fu, Rong-Bing; Xu, Zhen

2015-02-01

Electric field distributions of several different electrode configurations in non-uniform electric field were simulated using MATLAB software, and the electrokinetic remediation device was constructed according to the best electrode configuration. The changes of soil pH and heavy metal residues in different parts of the device during the electrokinetic remediation were also studied. The results showed that, in terms of the effectiveness of the electric field strength, the square (1-D-1) and hexagonal (2-D-3) were the optimal electrode configurations for one-dimensional and two-dimensional respectively and the changes of soil pH, the removal of heavy metals and the distribution of electric field were closely related to one another. An acidic migration band, which could prevent premature precipitation of heavy metals to a certain extent and promote electrokinetic removal of heavy metals, was formed gradually along with the remediation in the whole hexagon device when the cathodic pH was controlled during the remediation of the four cationic metallic ions, Cd2+, Ni2+, Pb2+ and Cu2+. After 480-hour remediation, the total removals of Cd, Ni, Pb and Cu were 86.6%, 86.2%, 67.7% and 73.0%, respectively. Remediation duration and replacement frequency of the electrodes could be adjusted according to the repair target.

A Solar Volumetric Receiver: Influence of Absorbing Cells Configuration on Device Thermal Performance

Science.gov (United States)

Yilbas, B. S.; Shuja, S. Z.

2017-01-01

Thermal performance of a solar volumetric receiver incorporating the different cell geometric configurations is investigated. Triangular, hexagonal, and rectangular absorbing cells are incorporated in the analysis. The fluid volume fraction, which is the ratio of the volume of the working fluid over the total volume of solar volumetric receiver, is introduced to assess the effect of cell size on the heat transfer rates in the receiver. In this case, reducing the fluid volume fraction corresponds to increasing cell size in the receiver. SiC is considered as the cell material, and air is used as the working fluid in the receiver. The Lambert's Beer law is incorporated to account for the solar absorption in the receiver. A finite element method is used to solve the governing equation of flow and heat transfer. It is found that the fluid volume fraction has significant effect on the flow field in the solar volumetric receiver, which also modifies thermal field in the working fluid. The triangular absorbing cell gives rise to improved effectiveness of the receiver and then follows the hexagonal and rectangular cells. The second law efficiency of the receiver remains high when hexagonal cells are used. This occurs for the fluid volume fraction ratio of 0.5.

Electron heat transport analysis of low-collisionality plasmas in the neoclassical-transport-optimized configuration of LHD

International Nuclear Information System (INIS)

Murakami, Sadayoshi; Yamada, Hiroshi; Wakasa, Arimitsu

2002-01-01

Electron heat transport in low-collisionality LHD plasma is investigated in order to study the neoclassical transport optimization effect on thermal plasma transport with an optimization level typical of so-called ''advanced stellarators''. In the central region, a higher electron temperature is obtained in the optimized configuration, and transport analysis suggests the considerable effect of neoclassical transport on the electron heat transport assuming the ion-root level of radial electric field. The obtained experimental results support future reactor design in which the neoclassical and/or anomalous transports are reduced by magnetic field optimization in a non-axisymmetric configuration. (author)

Parallel implementation and performance optimization of the configuration-interaction method

Energy Technology Data Exchange (ETDEWEB)

Shan, H; Williams, S; Johnson, C; McElvain, K; Ormand, WE

2015-11-20

The configuration-interaction (CI) method, long a popular approach to describe quantum many-body systems, is cast as a very large sparse matrix eigenpair problem with matrices whose dimension can exceed one billion. Such formulations place high demands on memory capacity and memory bandwidth - - two quantities at a premium today. In this paper, we describe an efficient, scalable implementation, BIGSTICK, which, by factorizing both the basis and the interaction into two levels, can reconstruct the nonzero matrix elements on the fly, reduce the memory requirements by one or two orders of magnitude, and enable researchers to trade reduced resources for increased computational time. We optimize BIGSTICK on two leading HPC platforms - - the Cray XC30 and the IBM Blue Gene/Q. Specifically, we not only develop an empirically-driven load balancing strategy that can evenly distribute the matrix-vector multiplication across 256K threads, we also developed techniques that improve the performance of the Lanczos reorthogonalization. Combined, these optimizations improved performance by 1.3-8× depending on platform and configuration.

Optimal sensor configuration for flexible structures with multi-dimensional mode shapes

International Nuclear Information System (INIS)

Chang, Minwoo; Pakzad, Shamim N

2015-01-01

A framework for deciding the optimal sensor configuration is implemented for civil structures with multi-dimensional mode shapes, which enhances the applicability of structural health monitoring for existing structures. Optimal sensor placement (OSP) algorithms are used to determine the best sensor configuration for structures with a priori knowledge of modal information. The signal strength at each node is evaluated by effective independence and modified variance methods. Euclidean norm of signal strength indices associated with each node is used to expand OSP applicability into flexible structures. The number of sensors for each method is determined using the threshold for modal assurance criterion (MAC) between estimated (from a set of observations) and target mode shapes. Kriging is utilized to infer the modal estimates for unobserved locations with a weighted sum of known neighbors. A Kriging model can be expressed as a sum of linear regression and random error which is assumed as the realization of a stochastic process. This study presents the effects of Kriging parameters for the accurate estimation of mode shapes and the minimum number of sensors. The feasible ranges to satisfy MAC criteria are investigated and used to suggest the adequate searching bounds for associated parameters. The finite element model of a tall building is used to demonstrate the application of optimal sensor configuration. The dynamic modes of flexible structure at centroid are appropriately interpreted into the outermost sensor locations when OSP methods are implemented. Kriging is successfully used to interpolate the mode shapes from a set of sensors and to monitor structures associated with multi-dimensional mode shapes. (paper)

Optimization of the core configuration design using a hybrid artificial intelligence algorithm for research reactors

International Nuclear Information System (INIS)

Hedayat, Afshin; Davilu, Hadi; Barfrosh, Ahmad Abdollahzadeh; Sepanloo, Kamran

2009-01-01

To successfully carry out material irradiation experiments and radioisotope productions, a high thermal neutron flux at irradiation box over a desired life time of a core configuration is needed. On the other hand, reactor safety and operational constraints must be preserved during core configuration selection. Two main objectives and two safety and operational constraints are suggested to optimize reactor core configuration design. Suggested parameters and conditions are considered as two separate fitness functions composed of two main objectives and two penalty functions. This is a constrained and combinatorial type of a multi-objective optimization problem. In this paper, a fast and effective hybrid artificial intelligence algorithm is introduced and developed to reach a Pareto optimal set. The hybrid algorithm is composed of a fast and elitist multi-objective genetic algorithm (GA) and a fast fitness function evaluating system based on the cascade feed forward artificial neural networks (ANNs). A specific GA representation of core configuration and also special GA operators are introduced and used to overcome the combinatorial constraints of this optimization problem. A software package (Core Pattern Calculator 1) is developed to prepare and reform required data for ANNs training and also to revise the optimization results. Some practical test parameters and conditions are suggested to adjust main parameters of the hybrid algorithm. Results show that introduced ANNs can be trained and estimate selected core parameters of a research reactor very quickly. It improves effectively optimization process. Final optimization results show that a uniform and dense diversity of Pareto fronts are gained over a wide range of fitness function values. To take a more careful selection of Pareto optimal solutions, a revision system is introduced and used. The revision of gained Pareto optimal set is performed by using developed software package. Also some secondary operational

Optimization of the core configuration design using a hybrid artificial intelligence algorithm for research reactors

Energy Technology Data Exchange (ETDEWEB)

Hedayat, Afshin, E-mail: ahedayat@aut.ac.i [Department of Nuclear Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), 424 Hafez Avenue, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Reactor Research and Development School, Nuclear Science and Technology Research Institute (NSTRI), End of North Karegar Street, P.O. Box 14395-836, Tehran (Iran, Islamic Republic of); Davilu, Hadi [Department of Nuclear Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), 424 Hafez Avenue, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Barfrosh, Ahmad Abdollahzadeh [Department of Computer Engineering, Amirkabir University of Technology (Tehran Polytechnic), 424 Hafez Avenue, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Sepanloo, Kamran [Reactor Research and Development School, Nuclear Science and Technology Research Institute (NSTRI), End of North Karegar Street, P.O. Box 14395-836, Tehran (Iran, Islamic Republic of)

2009-12-15

To successfully carry out material irradiation experiments and radioisotope productions, a high thermal neutron flux at irradiation box over a desired life time of a core configuration is needed. On the other hand, reactor safety and operational constraints must be preserved during core configuration selection. Two main objectives and two safety and operational constraints are suggested to optimize reactor core configuration design. Suggested parameters and conditions are considered as two separate fitness functions composed of two main objectives and two penalty functions. This is a constrained and combinatorial type of a multi-objective optimization problem. In this paper, a fast and effective hybrid artificial intelligence algorithm is introduced and developed to reach a Pareto optimal set. The hybrid algorithm is composed of a fast and elitist multi-objective genetic algorithm (GA) and a fast fitness function evaluating system based on the cascade feed forward artificial neural networks (ANNs). A specific GA representation of core configuration and also special GA operators are introduced and used to overcome the combinatorial constraints of this optimization problem. A software package (Core Pattern Calculator 1) is developed to prepare and reform required data for ANNs training and also to revise the optimization results. Some practical test parameters and conditions are suggested to adjust main parameters of the hybrid algorithm. Results show that introduced ANNs can be trained and estimate selected core parameters of a research reactor very quickly. It improves effectively optimization process. Final optimization results show that a uniform and dense diversity of Pareto fronts are gained over a wide range of fitness function values. To take a more careful selection of Pareto optimal solutions, a revision system is introduced and used. The revision of gained Pareto optimal set is performed by using developed software package. Also some secondary operational

Optimizing the Configuration of Sensor Networks to Detect Intruders.

Energy Technology Data Exchange (ETDEWEB)

Brown, Nathanael J. K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Katherine A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nozick, Linda Karen [Cornell Univ., Ithaca, NY (United States); Xu, Ningxiong [Cornell Univ., Ithaca, NY (United States)

2015-03-01

This paper focuses on optimizing the selection and configuration of detection technologies to protect a target of interest. The ability of an intruder to simply reach the target is assumed to be sufficient to consider the security system a failure. To address this problem, we develop a game theoretic model of the strategic interactions between the system owner and a knowledgeable intruder. A decomposition-based exact method is used to solve the resultant model.

Millimeter‐wave INP DHBT power amplifier based on power‐optimized cascode configuration

DEFF Research Database (Denmark)

Johansen, Tom K.; Yan, Lei; Dupuy, Jean‐Yves

2013-01-01

This letter describes the use of a power‐optimized cascode configuration for obtaining maximum output power at millimeter‐wave (mm‐wave) frequencies for a two‐way combined power amplifier (PA). The PA has been fabricated in a high‐speed InP double heterojunction bipolar transistor technology and ...... configuration at mm‐wave frequencies are confirmed by both simulations and experimental results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1178–1182, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27477...

Optimal sensor configuration for complex systems with application to signal detection in structures

DEFF Research Database (Denmark)

Sadegh, Payman; Spall, J. C.

2000-01-01

sensor outputs. Secondly, we describe an efficient and practical algorithm to achieve the optimization goals, based on simultaneous perturbation stochastic approximation (SPSA). SPSA avoids the need for detailed modeling of the sensor response by simply relying on observed responses as obtained......The paper considers the problem of sensor configuration for complex systems. The contribution of the paper is twofold. Firstly, we define an appropriate criterion that is based on maximizing overall sensor responses while minimizing redundant information as measured by correlations between multiple...... by limited experimentation with test sensor configurations. We illustrate the application of the approach to optimal placement of acoustic sensors for signal detection in structures. This includes both a computer simulation study for an aluminum plate, and real experimentations on a steel I-beam....

Configuration optimization of series flow double-effect water-lithium bromide absorption refrigeration systems by cost minimization

DEFF Research Database (Denmark)

Mussati, Sergio F.; Cignitti, Stefano; Mansouri, Seyed Soheil

2018-01-01

An optimal process configuration for double-effect water-lithium bromide absorption refrigeration systems with series flow – where the solution is first passed through the high-temperature generator – is obtained by minimization of the total annual cost for a required cooling capacity. To this end......) takes place entirely at the high-temperature zone, and the sizes and operating conditions of the other process units change accordingly in order to meet the problem specification with the minimal total annual cost. This new configuration was obtained for wide ranges of the cooling capacity (150–450 k.......9%, respectively. Most importantly, the obtained optimal solution eliminates the low-temperature solution heat exchanger from the conventional configuration, rendering a new process configuration. The energy integration between the weak and strong lithium bromide solutions (cold and hot streams, respectively...

Particle transport and fluctuation characteristics around neoclassically optimized configurations in LHD

International Nuclear Information System (INIS)

Tanaka, K.; Michael, C.; Vyacheslavov, L.N.

2008-01-01

Density profiles in LHD were measured and particle transport coefficients were estimated from density modulation experiments in LHD. The data set contains the wide region of discharge condition. The dataset of different magnetic axis, toroidal magnetic field and heating power provided data set of widely scanned neoclassical transport. At minimized neoclassical transport configuration in the dataset (Rax=3.5m, Bt=2.8T) showed peaked density profile. Its peaking factor increased gradually with decrease of collisional frequency. This is a similar result observed in tokamak data base. At other configuration, peaking factor reduced with decrease of collisional frequency. Data set showed that larger contribution of neoclassical transport produced hollowed density profile. Comparison between neoclassical and experimental estimated particle diffusivity showed different minimum condition. This suggests neoclassical optimization is not same as anomalous optimization. Clear difference of spatial profile of turbulence was observed between hollowed and peaked density profiles. Major part of fluctuation existed in the unstable region of linear growth rate of ion temperature gradient mode. (author)

Fluid flow distribution optimization for minimizing the peak temperature of a tubular solar receiver

International Nuclear Information System (INIS)

Wei, Min; Fan, Yilin; Luo, Lingai; Flamant, Gilles

2015-01-01

High temperature solar receiver is a core component of solar thermal power plants. However, non-uniform solar irradiation on the receiver walls and flow maldistribution of heat transfer fluid inside the tubes may cause the excessive peak temperature, consequently leading to the reduced lifetime. This paper presents an original CFD (computational fluid dynamics)-based evolutionary algorithm to determine the optimal fluid distribution in a tubular solar receiver for the minimization of its peak temperature. A pressurized-air solar receiver comprising of 45 parallel tubes subjected to a Gaussian-shape net heat flux absorbed by the receiver is used for study. Two optimality criteria are used for the algorithm: identical outlet fluid temperatures and identical temperatures on the centerline of the heated surface. The influences of different filling materials and thermal contact resistances on the optimal fluid distribution and on the peak temperature reduction are also evaluated and discussed. Results show that the fluid distribution optimization using the algorithm could minimize the peak temperature of the receiver under the optimality criterion of identical temperatures on the centerline. Different shapes of optimal fluid distribution are determined for various filling materials. Cheap material with low thermal conductivity can also meet the peak temperature threshold through optimizing the fluid distribution. - Highlights: • A 3D pressurized-air solar receiver based on the tube-in-matrix concept is studied. • An original evolutionary algorithm is developed for fluid distribution optimization. • A new optimality criterion is proposed for minimizing the receiver peak temperature. • Different optimal fluid distributions are determined for various filling materials. • Filling material with high thermal conductivity is more favorable in practical use.

Baseline configuration for GNSS attitude determination with an analytical least-squares solution

International Nuclear Information System (INIS)

Chang, Guobin; Wang, Qianxin; Xu, Tianhe

2016-01-01

The GNSS attitude determination using carrier phase measurements with 4 antennas is studied on condition that the integer ambiguities have been resolved. The solution to the nonlinear least-squares is often obtained iteratively, however an analytical solution can exist for specific baseline configurations. The main aim of this work is to design this class of configurations. Both single and double difference measurements are treated which refer to the dedicated and non-dedicated receivers respectively. More realistic error models are employed in which the correlations between different measurements are given full consideration. The desired configurations are worked out. The configurations are rotation and scale equivariant and can be applied to both the dedicated and non-dedicated receivers. For these configurations, the analytical and optimal solution for the attitude is also given together with its error variance–covariance matrix. (paper)

Theory of the optimal design of straight-axis minimum-B mirror confinement configurations

International Nuclear Information System (INIS)

Hall, L.S.

1982-01-01

The design of modern straight-axis linked-mirror plasma-confinement configurations involves a balance between many competing requirements. The dipole and quadrupole components of magnetic induction required in one confinement region often do not match onto the fields of an adjacent region without complications that seriously affect particle drifts or confinement stability. Here, the relevant factors are set down together with the techniques for analytical optimization of the design of a general configuration. A general sufficient condition for the stability of an arbitrary guiding-center MHD equilibrium is derived. This condition makes explicit the stabilizing qualities of good normal curvature and diamagnetic axial current. The instability drive depends on two terms: one carries the sign of normal curvature and the other relates to the relative signs of geodeics curvature and geodesic torsion. The theory is applied to low-beta, large-aspect-ratio equilibria for which analytic expressions for the confining magnetic fields are known. Two optimizations are required to specify the arbitrary features of the quadrupole and dipole fields. One optimization is nonlinear and can be performed by the ordinary calculus of variations; the second optimization is linear and subject to the rules of game theory. Appropriate quality factors are obtained, thus giving the designer quantitative measures with which to balance design trade-offs

Multi-objective optimization and grey relational analysis on configurations of organic Rankine cycle

International Nuclear Information System (INIS)

Wang, Y.Z.; Zhao, J.; Wang, Y.; An, Q.S.

2017-01-01

Highlights: • Pareto frontier is an effective way to make comprehensive comparison of ORC. • Comprehensive performance from energy and economics of basic ORC is the best. • R141b shows the best comprehensive performance from energy and economics. - Abstract: Concerning the comprehensive performance of organic Rankine cycle (ORC), comparisons and optimizations on 3 different configurations of ORC (basic, regenerative and extractive ORCs) are investigated in this paper. Medium-temperature geothermal water is used for comparing the influence of configurations, working fluids and operating parameters on different evaluation criteria. Different evaluation and optimization methods are adopted in evaluation of ORCs to obtain the one with the best comprehensive performance, such as exergoeconomic analysis, bi-objective optimization and grey relational analysis. The results reveal that the basic ORC performs the best among these 3 ORCs in terms of comprehensive thermodynamic and economic performances when using R245fa and driven by geothermal water at 150 °C. Furthermore, R141b shows the best comprehensive performance among 14 working fluids based on the Pareto frontier solutions without considering safe factors. Meanwhile, R141b is the best among all 14 working fluids with the optimal comprehensive performance when regarding all the evaluation criteria as equal by using grey relational analysis.

Performance Comparison of the Optimized Inverted Joined Wing Airplane Concept and Classical Configuration Airplanes

OpenAIRE

Sieradzki Adam; Dziubiński Adam; Galiński Cezary

2016-01-01

The joined wing concept is an unconventional airplane configuration, known since the mid-twenties of the last century. It has several possible advantages, like reduction of the induced drag and weight due to the closed wing concept. The inverted joined wing variant is its rarely considered version, with the front wing being situated above the aft wing. The following paper presents a performance prediction of the recently optimized configuration of this airplane. Flight characteristics obtaine...

Optimization of Wind-Marine Hybrid Power System Configuration Based on Genetic Algorithm

Institute of Scientific and Technical Information of China (English)

SHI Hongda; LI Linna; ZHAO Chenyu

2017-01-01

Multi-energy power systems can use energy generated from various sources to improve power generation reliability.This paper presents a cost-power generation model of a wind-tide-wave energy hybrid power system for use on a remote island,where the configuration is optimized using a genetic algorithm.A mixed integer programming model is used and a novel object function,including cost and power generation,is proposed to solve the boundary problem caused by existence of two goals.Using this model,the final optimized result is found to have a good fit with local resources.

Inclusion of tank configurations as a variable in the cost optimization of branched piped-water networks

Science.gov (United States)

Hooda, Nikhil; Damani, Om

2017-06-01

The classic problem of the capital cost optimization of branched piped networks consists of choosing pipe diameters for each pipe in the network from a discrete set of commercially available pipe diameters. Each pipe in the network can consist of multiple segments of differing diameters. Water networks also consist of intermediate tanks that act as buffers between incoming flow from the primary source and the outgoing flow to the demand nodes. The network from the primary source to the tanks is called the primary network, and the network from the tanks to the demand nodes is called the secondary network. During the design stage, the primary and secondary networks are optimized separately, with the tanks acting as demand nodes for the primary network. Typically the choice of tank locations, their elevations, and the set of demand nodes to be served by different tanks is manually made in an ad hoc fashion before any optimization is done. It is desirable therefore to include this tank configuration choice in the cost optimization process itself. In this work, we explain why the choice of tank configuration is important to the design of a network and describe an integer linear program model that integrates the tank configuration to the standard pipe diameter selection problem. In order to aid the designers of piped-water networks, the improved cost optimization formulation is incorporated into our existing network design system called JalTantra.

Fault detection and isolation in GPS receiver autonomous integrity monitoring based on chaos particle swarm optimization-particle filter algorithm

Science.gov (United States)

Wang, Ershen; Jia, Chaoying; Tong, Gang; Qu, Pingping; Lan, Xiaoyu; Pang, Tao

2018-03-01

The receiver autonomous integrity monitoring (RAIM) is one of the most important parts in an avionic navigation system. Two problems need to be addressed to improve this system, namely, the degeneracy phenomenon and lack of samples for the standard particle filter (PF). However, the number of samples cannot adequately express the real distribution of the probability density function (i.e., sample impoverishment). This study presents a GPS receiver autonomous integrity monitoring (RAIM) method based on a chaos particle swarm optimization particle filter (CPSO-PF) algorithm with a log likelihood ratio. The chaos sequence generates a set of chaotic variables, which are mapped to the interval of optimization variables to improve particle quality. This chaos perturbation overcomes the potential for the search to become trapped in a local optimum in the particle swarm optimization (PSO) algorithm. Test statistics are configured based on a likelihood ratio, and satellite fault detection is then conducted by checking the consistency between the state estimate of the main PF and those of the auxiliary PFs. Based on GPS data, the experimental results demonstrate that the proposed algorithm can effectively detect and isolate satellite faults under conditions of non-Gaussian measurement noise. Moreover, the performance of the proposed novel method is better than that of RAIM based on the PF or PSO-PF algorithm.

Steady-state configuration and tension calculations of marine cables under complex currents via separated particle swarm optimization

Science.gov (United States)

Xu, Xue-song

2014-12-01

Under complex currents, the motion governing equations of marine cables are complex and nonlinear, and the calculations of cable configuration and tension become difficult compared with those under the uniform or simple currents. To obtain the numerical results, the usual Newton-Raphson iteration is often adopted, but its stability depends on the initial guessed solution to the governing equations. To improve the stability of numerical calculation, this paper proposed separated the particle swarm optimization, in which the variables are separated into several groups, and the dimension of search space is reduced to facilitate the particle swarm optimization. Via the separated particle swarm optimization, these governing nonlinear equations can be solved successfully with any initial solution, and the process of numerical calculation is very stable. For the calculations of cable configuration and tension of marine cables under complex currents, the proposed separated swarm particle optimization is more effective than the other particle swarm optimizations.

Optimal and Modular Configuration of Wind Integrated Hybrid Power Plants for Off-Grid Systems

DEFF Research Database (Denmark)

Petersen, Lennart; Iov, Florin; Tarnowski, German Claudio

2018-01-01

This paper focusses on the system configuration of offgrid hybrid power plants including wind power generation. First, a modular and scalable system topology is proposed. Secondly, an optimal sizing algorithm is developed in order to determine the installed capacities of wind turbines, PV system......, battery energy storage system and generator sets. The novelty of this work lies in a robust sizing algorithm with respect to the required resolution of resource data in order to account for intra-hour power variations. Moreover, the involvement of the electrical infrastructure enables a precise estimation...... of power losses within the hybrid power plant as well as the consideration of both active and reactive power load demand for optimally sizing the plant components. The main outcome of this study is a methodology to determine feasible system configurations of modular and scalable wind integrated hybrid...

A Study on the Optimal Receiver Impedance for SNR Maximization in Broadband PLC

Directory of Open Access Journals (Sweden)

Massimo Antoniali

2013-01-01

Full Text Available We consider the design of the front-end receiver for broadband power line communications. We focus on the design of the input impedance that maximizes the signal-to-noise ratio (SNR at the receiver. We show that the amplitude, rather than the power, of the received signal is important for communication purposes. Furthermore, we show that the receiver impedance impacts the amplitude of the noise term. We focus on the background noise, and we propose a novel description of the noise experienced at the receiver port of a PLC network. We model the noise as the sum of four uncorrelated contributions, that is, the active, resistive, receiver, and coupled noise components. We study the optimal impedance design problem for real in-home grids that we assessed with experimental measurements. We describe the results of the measurement campaign, and we report the statistics of the optimal impedance. Hence, we study the best attainable performance when the optimal receiver impedance is deployed. We focus on the SNR and the maximum achievable rate, and we show that power matching is suboptimal with respect to the proposed impedance design approach.

PWR [pressurized water reactor] optimal reload configuration with an intelligent workstation

International Nuclear Information System (INIS)

Greek, K.J.; Robinson, A.H.

1990-01-01

In a previous paper, the implementation of a pressurized water reactor (PWR) refueling expert system that combined object-oriented programming in Smalltalk and a FORTRAN power calculation to evaluate loading patterns was discussed. The expert system applies heuristics and constraints that lead the search toward an optimal configuration. Its rate of improvement depends on the expertise coded for a search and the loading pattern from where the search begins. Due to its complexity, however, the solution normally cannot be served by a rule-based expert system alone. A knowledge base may take years of development before final acceptance. Also, the human pattern-matching capability to view a two-dimensional power profile, recognize an imbalance, and select an appropriate response has not yet been surpassed by a rule-based system. The user should be given the ability to take control of the search if he believes the solution needs a new direction and should be able to configure a loading pattern and resume the search. This paper introduces the workstation features of Shuffle important to aid the user to manipulate the configuration and retain a record of the solution

Optimization of process parameter and reformer configuration for hydrogen production from steam reforming of heavy hydrocarbons. Paper no. IGEC-1-079

International Nuclear Information System (INIS)

Chen, Z.; Elnashaie, S.E.H.

2005-01-01

The present optimization investigation is classified into reforming configuration optimization in one hand and parameter optimization of each configuration on the other hand. Heptane is used as a model component for heavy hydrocarbons. The proposed novel reforming process is basically a Circulating Fluidized-Bed Membrane Reformer (CFBMR) with continuous catalyst regeneration and gas-solid separation. Composite hydrogen selective membranes are used for removing the product hydrogen from the reacting gas mixture and therefore driving the reversible reactions beyond their thermodynamic equilibriums. Dense perovskite oxygen selective membranes are also used to introduce oxygen for the exothermic oxidation of hydrocarbons and carbon. Four configurations are investigated, two of them are with the catalyst regeneration before the gas-solid separation and the other two are with the catalyst regeneration after the gas-solid separation. The optimization of the performance of each configuration is carried out for a number of design and operating parameters as optimization parameters and under both non-autothermal and autothermal reforming conditions. Results show that the autothermal operation with direct contact between cold feeds (water and heptane) and hot circulating catalyst can be the best configuration for efficient hydrogen production with minimum energy consumption. The maximum net hydrogen yield is 16.732 moles of hydrogen per mole of heptane fed, which is 76.05% of the maximum theoretical hydrogen yield of 22. (author)

Optimal configuration of spatial points in the reactor cell

International Nuclear Information System (INIS)

Bosevski, T.

1968-01-01

Optimal configuration of spatial points was chosen in respect to the total number needed for integration of reactions in the reactor cell. Previously developed code VESTERN was used for numerical verification of the method on a standard reactor cell. The code applies the collision probability method for calculating the neutron flux distribution. It is shown that the total number of spatial points is twice smaller than the respective number of spatial zones needed for determination of number of reactions in the cell, with the preset precision. This result shows the direction for further condensing of the procedure for calculating the space-energy distribution of the neutron flux in a reactors cell [sr

Strain sensors optimal placement for vibration-based structural health monitoring. The effect of damage on the initially optimal configuration

Science.gov (United States)

Loutas, T. H.; Bourikas, A.

2017-12-01

We revisit the optimal sensor placement of engineering structures problem with an emphasis on in-plane dynamic strain measurements and to the direction of modal identification as well as vibration-based damage detection for structural health monitoring purposes. The approach utilized is based on the maximization of a norm of the Fisher Information Matrix built with numerically obtained mode shapes of the structure and at the same time prohibit the sensorization of neighbor degrees of freedom as well as those carrying similar information, in order to obtain a satisfactory coverage. A new convergence criterion of the Fisher Information Matrix (FIM) norm is proposed in order to deal with the issue of choosing an appropriate sensor redundancy threshold, a concept recently introduced but not further investigated concerning its choice. The sensor configurations obtained via a forward sequential placement algorithm are sub-optimal in terms of FIM norm values but the selected sensors are not allowed to be placed in neighbor degrees of freedom providing thus a better coverage of the structure and a subsequent better identification of the experimental mode shapes. The issue of how service induced damage affects the initially nominated as optimal sensor configuration is also investigated and reported. The numerical model of a composite sandwich panel serves as a representative aerospace structure upon which our investigations are based.

Study on optimal configuration of the grid-connected wind-solar-battery hybrid power system

Science.gov (United States)

Ma, Gang; Xu, Guchao; Ju, Rong; Wu, Tiantian

2017-08-01

The capacity allocation of each energy unit in the grid-connected wind-solar-battery hybrid power system is a significant segment in system design. In this paper, taking power grid dispatching into account, the research priorities are as follows: (1) We establish the mathematic models of each energy unit in the hybrid power system. (2) Based on dispatching of the power grid, energy surplus rate, system energy volatility and total cost, we establish the evaluation system for the wind-solar-battery power system and use a number of different devices as the constraint condition. (3) Based on an improved Genetic algorithm, we put forward a multi-objective optimisation algorithm to solve the optimal configuration problem in the hybrid power system, so we can achieve the high efficiency and economy of the grid-connected hybrid power system. The simulation result shows that the grid-connected wind-solar-battery hybrid power system has a higher comprehensive performance; the method of optimal configuration in this paper is useful and reasonable.

Analytic model for ultrasound energy receivers and their optimal electric loads

Science.gov (United States)

Gorostiaga, M.; Wapler, M. C.; Wallrabe, U.

2017-08-01

In this paper, we present an analytic model for thickness resonating plate ultrasound energy receivers, which we have derived from the piezoelectric and the wave equations and, in which we have included dielectric, viscosity and acoustic attenuation losses. Afterwards, we explore the optimal electric load predictions by the zero reflection and power maximization approaches present in the literature with different acoustic boundary conditions, and discuss their limitations. To validate our model, we compared our expressions with the KLM model solved numerically with very good agreement. Finally, we discuss the differences between the zero reflection and power maximization optimal electric loads, which start to differ as losses in the receiver increase.

Re-configurable digital receiver for optically envelope detected half cycle BPSK and MSK radio-on-fiber signals

DEFF Research Database (Denmark)

Guerrero Gonzalez, Neil; Prince, Kamau; Zibar, Darko

2011-01-01

We present the first known integration of a digital receiver into optically envelope detection radio-on-fiber systems. We also present a re-configurable scheme for two different types of optically envelope detected wireless signals while keeping the complexity of used optical components low. Our...... novel digital receiver consists of a digital signal processing unit integrating functions such as filtering, peak-powers detection, symbol synchronization and signal demodulation for optically envelope detected half-cycle binary phase-shift-keying and minimum-shift-keying signals. Furthermore, radio......-frequency signal down-conversion is not required in our proposed approach; simplifying evens more the optical receiver front-end. We experimentally demonstrate error-free optical transmission (bit-error rate corresponding to 10−3 related to FEC-compatible levels) for both 416.6 Mbit/s half-cycle binary phase...

Optimization of traffic distribution control in software-configurable infrastructure of virtual data center based on a simulation model

Directory of Open Access Journals (Sweden)

I. P. Bolodurina

2017-01-01

Full Text Available Currently, the proportion of use of cloud computing technology in today's business processes of companies is growing steadily. Despite the fact that it allows you to reduce the cost of ownership and operation of IT infrastructure, there are a number of problems related to the control of data centers. One such problem is the efficiency of the use of available companies compute and network resources. One of the directions of optimization is the process of traffic control of cloud applications and services in data centers. Given the multi-tier architecture of modern data center, this problem does not quite trivial. The advantage of modern virtual infrastructure is the ability to use software-configurable networks and software-configurable data storages. However, existing solutions with algorithmic optimization does not take into account a number of features forming network traffic with multiple classes of applications. Within the framework of the exploration solved the problem of optimizing the distribution of traffic cloud applications and services for the software-controlled virtual data center infrastructure. A simulation model describing the traffic in data center and software-configurable network segments involved in the processing of user requests for applications and services located network environment that includes a heterogeneous cloud platform and software-configurable data storages. The developed model has allowed to implement cloud applications traffic management algorithm and optimize access to the storage system through the effective use of the channel for data transmission. In experimental studies found that the application of the developed algorithm can reduce the response time of cloud applications and services, and as a result improve the performance of processing user requests and to reduce the number of failures.

Order of magnitude sensitivity increase in X-ray Fluorescence Computed Tomography (XFCT) imaging with an optimized spectro-spatial detector configuration: theory and simulation.

Science.gov (United States)

Ahmad, Moiz; Bazalova, Magdalena; Xiang, Liangzhong; Xing, Lei

2014-05-01

The purpose of this study was to increase the sensitivity of XFCT imaging by optimizing the data acquisition geometry for reduced scatter X-rays. The placement of detectors and detector energy window were chosen to minimize scatter X-rays. We performed both theoretical calculations and Monte Carlo simulations of this optimized detector configuration on a mouse-sized phantom containing various gold concentrations. The sensitivity limits were determined for three different X-ray spectra: a monoenergetic source, a Gaussian source, and a conventional X-ray tube source. Scatter X-rays were minimized using a backscatter detector orientation (scatter direction > 110(°) to the primary X-ray beam). The optimized configuration simultaneously reduced the number of detectors and improved the image signal-to-noise ratio. The sensitivity of the optimized configuration was 10 μg/mL (10 pM) at 2 mGy dose with the mono-energetic source, which is an order of magnitude improvement over the unoptimized configuration (102 pM without the optimization). Similar improvements were seen with the Gaussian spectrum source and conventional X-ray tube source. The optimization improvements were predicted in the theoretical model and also demonstrated in simulations. The sensitivity of XFCT imaging can be enhanced by an order of magnitude with the data acquisition optimization, greatly enhancing the potential of this modality for future use in clinical molecular imaging.

Cost optimization of biofuel production – The impact of scale, integration, transport and supply chain configurations

NARCIS (Netherlands)

de Jong, S.A.|info:eu-repo/dai/nl/41200836X; Hoefnagels, E.T.A.|info:eu-repo/dai/nl/313935998; Wetterlund, Elisabeth; Pettersson, Karin; Faaij, André; Junginger, H.M.|info:eu-repo/dai/nl/202130703

2017-01-01

This study uses a geographically-explicit cost optimization model to analyze the impact of and interrelation between four cost reduction strategies for biofuel production: economies of scale, intermodal transport, integration with existing industries, and distributed supply chain configurations

Analysis and optimization of three main organic Rankine cycle configurations using a set of working fluids with different thermodynamic behaviors

Science.gov (United States)

Hamdi, Basma; Mabrouk, Mohamed Tahar; Kairouani, Lakdar; Kheiri, Abdelhamid

2017-06-01

Different configurations of organic Rankine cycle (ORC) systems are potential thermodynamic concepts for power generation from low grade heat. The aim of this work is to investigate and optimize the performances of the three main ORC systems configurations: basic ORC, ORC with internal heat exchange (IHE) and regenerative ORC. The evaluation for those configurations was performed using seven working fluids with typical different thermodynamic behaviours (R245fa, R601a, R600a, R227ea, R134a, R1234ze and R1234yf). The optimization has been performed using a genetic algorithm under a comprehensive set of operative parameters such as the fluid evaporating temperature, the fraction of flow rate or the pressure at the steam extracting point in the turbine. Results show that there is no general best ORC configuration for all those fluids. However, there is a suitable configuration for each fluid. Contribution to the topical issue "Materials for Energy harvesting, conversion and storage II (ICOME 2016)", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

Optimal design of a novel configuration of MR brake with coils placed on the side housings

Science.gov (United States)

Nguyen, Quoc Hung; Nguyen, Ngoc Diep; Choi, Seung-Bok

2014-03-01

It is well known that in design of traditional magneto-rheological brake (MRB), coils are placed on the cylindrical housing of the brake. In this study, a new configuration of MR brake with coils placed on the side housings of the brake is proposed and analyzed. After briefly explaining the operating principle of the proposed configuration, the braking torque of the MR brake is analyze based on Bingham-plastic rheological model of MR fluid. The optimization of the proposed and conventional MR brakes is then performed considering maximum braking torque and mass of the brake. Based on the optimal results, a comparison between the proposed MR brakes and the conventional ones is undertaken. In addition, experimental test of the MR brakes is conducted and the results are presented in order to validate the performance characteristics of the proposed MR brake.

Multi-objective optimization of the carbon dioxide transcritical power cycle with various configurations for engine waste heat recovery

International Nuclear Information System (INIS)

Tian, Hua; Chang, Liwen; Shu, Gequn; Shi, Lingfeng

2017-01-01

Highlights: • A systematic optimization methodology is presented for carbon dioxide power cycle. • Adding the regenerator is a significant means to improve the system performance. • A decision making based on the optimization results is conducted in depth. • Specific optimal solutions are selected from Pareto fronts for different demands. - Abstract: In this paper, a systematic multi-objective optimization methodology is presented for the carbon dioxide transcritical power cycle with various configurations used in engine waste heat recovery to generate more power efficiently and economically. The parametric optimization is performed for the maximum net power output and exergy efficiency, as well as the minimum electricity production cost by using the genetic algorithm. The comparison of the optimization results shows the thermodynamic performance can be most enhanced by simultaneously adding the preheater and regenerator based on the basic configuration, and the highest net power output and exergy efficiency are 25.89 kW and 40.95%, respectively. Meanwhile, the best economic performance corresponding to the lowest electricity production cost of 0.560$/kW·h is achieved with simply applying an additional regenerator. Moreover, a thorough decision making is conducted for a further screening of the obtained optimal solutions. A most preferred Pareto optimal solution or a representative subset of the Pareto optimal solutions is obtained according to additional subjective preferences while a referential optimal solution is also provided on the condition of no additional preference.

The Implementation of a 2/4/8 Antennas Configurable Diversity OFDM Receiver for Mobile HDTV Application

Directory of Open Access Journals (Sweden)

Jing Gao

2009-01-01

Full Text Available Two pre-FFT adaptive array (AA antenna combiners and a post-FFT carrier diversity (CD combiner are integrated with a Japan Terrestrial digital TV (ISDB-T OFDM receiver using 90 nm 7M1P CMOS process. A 2/4/8-antenna diversity receiver can be configured and a low-cost 4 antenna diversity reception system can be realized in one LSI by making use of the AA-CD two-stage diversity combining method. Mobile reception performance is increased by 1.63 times using a denoise filter circuit and SPLINE interpolator under urban 6-path Rayleigh fading (TU6 model with 2-antenna post-FFT carrier diversity (2CD combing mode. The die area is 49 mm2 and the power consumption is 310 mW.

Application and Optimization of Kalman Filter for Baseband Signal Processing of GPS Receivers

Directory of Open Access Journals (Sweden)

He Yanpin

2016-01-01

Full Text Available High sensitivity tracking in GPS receiver is required in many weak signal circumstances. The key of improving sensitivity is the optimization of the loop filter in tracking. As Kalman filter is the most optimized linear filter, it is used in many engineering fields. This article introduced the application of Kalman filter as the loop filter of the carrier tracking loop in GPS receiver, to improve tracking sensitivity. The traditional loop filter is replaced. Simulation results show that the new structure improves the tracking sensitivity by 6dB and can make the tracking loop more robust when the navigation signal is languishing. The optimization of theKalman filter is also analysed, which further improves the sensitivity by 4dB.

Joint Optimization of Receiver Placement and Illuminator Selection for a Multiband Passive Radar Network.

Science.gov (United States)

Xie, Rui; Wan, Xianrong; Hong, Sheng; Yi, Jianxin

2017-06-14

The performance of a passive radar network can be greatly improved by an optimal radar network structure. Generally, radar network structure optimization consists of two aspects, namely the placement of receivers in suitable places and selection of appropriate illuminators. The present study investigates issues concerning the joint optimization of receiver placement and illuminator selection for a passive radar network. Firstly, the required radar cross section (RCS) for target detection is chosen as the performance metric, and the joint optimization model boils down to the partition p -center problem (PPCP). The PPCP is then solved by a proposed bisection algorithm. The key of the bisection algorithm lies in solving the partition set covering problem (PSCP), which can be solved by a hybrid algorithm developed by coupling the convex optimization with the greedy dropping algorithm. In the end, the performance of the proposed algorithm is validated via numerical simulations.

Optimization of Variable-Depth Liner Configurations for Increased Broadband Noise Reduction

Science.gov (United States)

Jones, M. G.; Watson, W. R.; Nark, D. M.; Schiller, N. H.; Born, J. C.

2016-01-01

This paper employs three acoustic propagation codes to explore variable-depth liner configurations for the NASA Langley Grazing Flow Impedance Tube (GFIT). The initial study demonstrates that a variable impedance can acceptably be treated as a uniform impedance if the spatial extent over which this variable impedance occurs is less than one-third of a wavelength of the incident sound. A constrained optimization study is used to design a variable-depth liner and to select an optimization metric. It also provides insight regarding how much attenuation can be achieved with variable-depth liners. Another optimization study is used to design a liner with much finer chamber depth resolution for the Mach 0.0 and 0.3 test conditions. Two liners are designed based on spatial rearrangement of chambers from this liner to determine whether the order is critical. Propagation code predictions suggest this is not the case. Both liners are fabricated via additive manufacturing and tested in the GFIT for the Mach 0.0 condition. Predicted and measured attenuations compare favorably across the full frequency range. These results clearly suggest that the chambers can be arranged in any order, thus offering the potential for innovative liner designs to minimize depth and weight.

Configuration space analysis of common cost functions in radiotherapy beam-weight optimization algorithms

Energy Technology Data Exchange (ETDEWEB)

Rowbottom, Carl Graham [Joint Department of Physics, Institute of Cancer Research and the Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Webb, Steve [Joint Department of Physics, Institute of Cancer Research and the Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom)

2002-01-07

The successful implementation of downhill search engines in radiotherapy optimization algorithms depends on the absence of local minima in the search space. Such techniques are much faster than stochastic optimization methods but may become trapped in local minima if they exist. A technique known as 'configuration space analysis' was applied to examine the search space of cost functions used in radiotherapy beam-weight optimization algorithms. A downhill-simplex beam-weight optimization algorithm was run repeatedly to produce a frequency distribution of final cost values. By plotting the frequency distribution as a function of final cost, the existence of local minima can be determined. Common cost functions such as the quadratic deviation of dose to the planning target volume (PTV), integral dose to organs-at-risk (OARs), dose-threshold and dose-volume constraints for OARs were studied. Combinations of the cost functions were also considered. The simple cost function terms such as the quadratic PTV dose and integral dose to OAR cost function terms are not susceptible to local minima. In contrast, dose-threshold and dose-volume OAR constraint cost function terms are able to produce local minima in the example case studied. (author)

ZEUS-DO: A Design Oriented CFD-Based Unsteady Aerodynamic Capability for Flight Vehicle Multidisciplinary Configuration Shape Optimization, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In practically all air-vehicle MDO studies to date involving configuration shape optimization, dynamic Aeroservoelastic constraints had to be left out. Flutter, gust...

Design of optimal wind farm configuration using a binary particle swarm optimization at Huasai district, Southern Thailand

International Nuclear Information System (INIS)

Pookpunt, Sittichoke; Ongsakul, Weerakorn

2016-01-01

Highlights: • Real wind data form a wind distributed map use in wind farm optimization algorithm. • Practical cost benefit is evaluated in the objective function. • Learning curve is developed to determine a wind farm cost model. • BPSO-TVAC simultaneously optimizes wind farm spacing, position, sizing, hub height. • Optimal placement shows improvement of operating income over conventional layout. - Abstract: This paper proposes the design of optimal wind farm configuration using a new wind probability distribution map at Huasai district, the east coast of Southern Thailand. The new wind probability distribution map integrates both frequency of wind speed and direction data at a monitoring site. The linear wake effect model is used to determine the wind speed at downstream turbines for the total power extraction from a wind farm array. The component cost model and learning curve is used to express the initial investment cost, levelized cost and the annual energy production cost of a wind farm, depending on the number of wind turbines, the installed size, hub height and wake loss within a wind farm. Based on Thailand wind energy selling price consisting of the fixed wind premium on top of base tariff, the profit depends on revenue of selling electricity and cost of energy. In this paper, Binary Particle Swarm Optimization with Time-Varying Acceleration Coefficients (BPSO-TVAC) is proposed to maximize profit subject to turbine position, turbine size, hub height, annual energy production, investment budget, land lease cost, operation and maintenance cost and levelized replacement cost constraints. Test results indicate that BPSO-TVAC optimally locate wind turbines directly facing the high frequent wind speed and direction, leading to a higher profit than the conventional wind farm layout.

Automated firewall analytics design, configuration and optimization

CERN Document Server

Al-Shaer, Ehab

2014-01-01

This book provides a comprehensive and in-depth study of automated firewall policy analysis for designing, configuring and managing distributed firewalls in large-scale enterpriser networks. It presents methodologies, techniques and tools for researchers as well as professionals to understand the challenges and improve the state-of-the-art of managing firewalls systematically in both research and application domains. Chapters explore set-theory, managing firewall configuration globally and consistently, access control list with encryption, and authentication such as IPSec policies. The author

Optimal configuration of partial Mueller matrix polarimeter for measuring the ellipsometric parameters in the presence of Poisson shot noise and Gaussian noise

Science.gov (United States)

Quan, Naicheng; Zhang, Chunmin; Mu, Tingkui

2018-05-01

We address the optimal configuration of a partial Mueller matrix polarimeter used to determine the ellipsometric parameters in the presence of additive Gaussian noise and signal-dependent shot noise. The numerical results show that, for the PSG/PSA consisting of a variable retarder and a fixed polarizer, the detection process immune to these two types of noise can be optimally composed by 121.2° retardation with a pair of azimuths ±71.34° and a 144.48° retardation with a pair of azimuths ±31.56° for four Mueller matrix elements measurement. Compared with the existing configurations, the configuration presented in this paper can effectively decrease the measurement variance and thus statistically improve the measurement precision of the ellipsometric parameters.

Optimal Piezoelectric Actuators and Sensors Configuration for Vibration Suppression of Aircraft Framework Using Particle Swarm Algorithm

Directory of Open Access Journals (Sweden)

Quanzhen Huang

2017-01-01

Full Text Available Numbers and locations of sensors and actuators play an important role in cost and control performance for active vibration control system of piezoelectric smart structure. This may lead to a diverse control system if sensors and actuators were not configured properly. An optimal location method of piezoelectric actuators and sensors is proposed in this paper based on particle swarm algorithm (PSA. Due to the complexity of the frame structure, it can be taken as a combination of many piezoelectric intelligent beams and L-type structures. Firstly, an optimal criterion of sensors and actuators is proposed with an optimal objective function. Secondly, each order natural frequency and modal strain are calculated and substituted into the optimal objective function. Preliminary optimal allocation is done using the particle swarm algorithm, based on the similar optimization method and the combination of the vibration stress and strain distribution at the lower modal frequency. Finally, the optimal location is given. An experimental platform was established and the experimental results indirectly verified the feasibility and effectiveness of the proposed method.

Performance Comparison of the Optimized Inverted Joined Wing Airplane Concept and Classical Configuration Airplanes

Directory of Open Access Journals (Sweden)

Sieradzki Adam

2016-09-01

Full Text Available The joined wing concept is an unconventional airplane configuration, known since the mid-twenties of the last century. It has several possible advantages, like reduction of the induced drag and weight due to the closed wing concept. The inverted joined wing variant is its rarely considered version, with the front wing being situated above the aft wing. The following paper presents a performance prediction of the recently optimized configuration of this airplane. Flight characteristics obtained numerically were compared with the performance of two classical configuration airplanes of similar category. Their computational fluid dynamics (CFD models were created basing on available documentation, photographs and some inverse engineering methods. The analysis included simulations performed for a scale of 3-meter wingspan inverted joined wing demonstrator and also for real-scale manned airplanes. Therefore, the results of CFD calculations allowed us to assess the competitiveness of the presented concept, as compared to the most technologically advanced airplanes designed and manufactured to date. At the end of the paper, the areas where the inverted joined wing is better than conventional airplane were predicted and new research possibilities were described.

Optimization of an Angle-Aided Mirror Diversity Receiver for Indoor MIMO-VLC Systems

KAUST Repository

Park, Kihong

2017-02-07

In this paper, we investigate the channel correlation problem which affects the performance of indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. More specifically, in order to reduce the high correlation of channel matrix in MIMO-VLC intensity channel, we propose a non-imaging receiver called angle-aided mirror diversity receiver (AMDR) which utilizes not only a mirror placement but also a variation of orientation angle for the photodetector (PD) plane. Deploying a mirror helps reducing the correlation by blocking the reception of the light in one specific direction and by receiving additional light reflected in the mirror in another direction, while orienting the angle of PD plane into specific direction enables the directional reception of light. Applying a zero-forcing decorrelator at the receiver, we analyze the bit error rate (BER) performance for a 2×2 multiplexing MIMO-VLC system using a 2-dimensional geometric model. In particular, we formulate a min-max BER problem and find the optimal height of mirror and elevation angle of PD plane. Some selected numerical results validate our proposed optimal solution to our min-max BER problem and show that the BER performance of our proposed AMDR outperforms that of the previous non-imaging receivers.

Optimization of an Angle-Aided Mirror Diversity Receiver for Indoor MIMO-VLC Systems

KAUST Repository

Park, Kihong; Alouini, Mohamed-Slim

2017-01-01

In this paper, we investigate the channel correlation problem which affects the performance of indoor multiple-input multiple-output (MIMO) visible light communication (VLC) systems. More specifically, in order to reduce the high correlation of channel matrix in MIMO-VLC intensity channel, we propose a non-imaging receiver called angle-aided mirror diversity receiver (AMDR) which utilizes not only a mirror placement but also a variation of orientation angle for the photodetector (PD) plane. Deploying a mirror helps reducing the correlation by blocking the reception of the light in one specific direction and by receiving additional light reflected in the mirror in another direction, while orienting the angle of PD plane into specific direction enables the directional reception of light. Applying a zero-forcing decorrelator at the receiver, we analyze the bit error rate (BER) performance for a 2×2 multiplexing MIMO-VLC system using a 2-dimensional geometric model. In particular, we formulate a min-max BER problem and find the optimal height of mirror and elevation angle of PD plane. Some selected numerical results validate our proposed optimal solution to our min-max BER problem and show that the BER performance of our proposed AMDR outperforms that of the previous non-imaging receivers.

The Transimpedance Amplifier Noise Optimization for the Atmospheric Optical Link Receiver

OpenAIRE

A. Prokes

1996-01-01

This paper deals with design of wideband low-noise preamplifier of atmospheric optical link receiver. Sources of noise and the noise models for the PIN photodiode coupled to a transimpedance amplifier are described here. This paper presents the way of optimization the signal to noise ratio at the required frequency range.

Numerical evaluation of an innovative cup layout for open volumetric solar air receivers

Science.gov (United States)

Cagnoli, Mattia; Savoldi, Laura; Zanino, Roberto; Zaversky, Fritz

2016-05-01

This paper proposes an innovative volumetric solar absorber design to be used in high-temperature air receivers of solar power tower plants. The innovative absorber, a so-called CPC-stacked-plate configuration, applies the well-known principle of a compound parabolic concentrator (CPC) for the first time in a volumetric solar receiver, heating air to high temperatures. The proposed absorber configuration is analyzed numerically, applying first the open-source ray-tracing software Tonatiuh in order to obtain the solar flux distribution on the absorber's surfaces. Next, a Computational Fluid Dynamic (CFD) analysis of a representative single channel of the innovative receiver is performed, using the commercial CFD software ANSYS Fluent. The solution of the conjugate heat transfer problem shows that the behavior of the new absorber concept is promising, however further optimization of the geometry will be necessary in order to exceed the performance of the classical absorber designs.

Thermodynamic analysis and multi-objective optimization of various ORC (organic Rankine cycle) configurations using zeotropic mixtures

International Nuclear Information System (INIS)

Sadeghi, Mohsen; Nemati, Arash; Ghavimi, Alireza; Yari, Mortaza

2016-01-01

In this paper, the performance of the ORC (organic Rankine cycle) powered by geothermal water, in three different configurations, including the simple ORC, PTORC (parallel two-stage ORC) and STORC (series two-stage ORC), using zeotrpoic working fluids is investigated from the viewpoints of the energy and exergy. In addition, considering the net power output and TSP (turbine size parameter) as the two objective functions, the multi-objective optimization with the aim of maximizing the first function and minimizing the second one, is performed to determine the optimal values of decision variables including evaporators 1 and 2 pressure, the pinch point temperature difference and the superheating degree. The results show that using zeotropic mixtures as the working fluid instead of a pure fluid such as R245fa, leads to 27.76%, 24.98% and 24.79% improvement in power generation in the simple ORC, PTORC and STORC, respectively and also lower values of TSP. Moreover, it is observed that STORC has the highest amount of net power output and R407A can be selected as the most appropriate working fluid. The optimization results demonstrate that at the final optimum point achieved by Pareto frontier, the values of the objective functions are gained 877 kW and 0.08218 m, respectively. - Highlights: • Three different configurations of ORC powered by geothermal water are analyzed. • The thermodynamic performance of these systems using zeotrpoic mixtures is investigated. • Multi-objective optimization is performed to obtain optimum performance. • The Pareto-frontier is used to automatically select the most promising solutions.

The Transimpedance Amplifier Noise Optimization for the Atmospheric Optical Link Receiver

Directory of Open Access Journals (Sweden)

A. Prokes

1996-12-01

Full Text Available This paper deals with design of wideband low-noise preamplifier of atmospheric optical link receiver. Sources of noise and the noise models for the PIN photodiode coupled to a transimpedance amplifier are described here. This paper presents the way of optimization the signal to noise ratio at the required frequency range.

Analytic model for ultrasound energy receivers and their optimal electric loads II: Experimental validation

Science.gov (United States)

Gorostiaga, M.; Wapler, M. C.; Wallrabe, U.

2017-10-01

In this paper, we verify the two optimal electric load concepts based on the zero reflection condition and on the power maximization approach for ultrasound energy receivers. We test a high loss 1-3 composite transducer, and find that the measurements agree very well with the predictions of the analytic model for plate transducers that we have developed previously. Additionally, we also confirm that the power maximization and zero reflection loads are very different when the losses in the receiver are high. Finally, we compare the optimal load predictions by the KLM and the analytic models with frequency dependent attenuation to evaluate the influence of the viscosity.

Comparison between four dissimilar solar panel configurations

Science.gov (United States)

Suleiman, K.; Ali, U. A.; Yusuf, Ibrahim; Koko, A. D.; Bala, S. I.

2017-12-01

Several studies on photovoltaic systems focused on how it operates and energy required in operating it. Little attention is paid on its configurations, modeling of mean time to system failure, availability, cost benefit and comparisons of parallel and series-parallel designs. In this research work, four system configurations were studied. Configuration I consists of two sub-components arranged in parallel with 24 V each, configuration II consists of four sub-components arranged logically in parallel with 12 V each, configuration III consists of four sub-components arranged in series-parallel with 8 V each, and configuration IV has six sub-components with 6 V each arranged in series-parallel. Comparative analysis was made using Chapman Kolmogorov's method. The derivation for explicit expression of mean time to system failure, steady state availability and cost benefit analysis were performed, based on the comparison. Ranking method was used to determine the optimal configuration of the systems. The results of analytical and numerical solutions of system availability and mean time to system failure were determined and it was found that configuration I is the optimal configuration.

Bioreactors for plant cells: hardware configuration and internal environment optimization as tools for wider commercialization.

Science.gov (United States)

Georgiev, Milen I; Weber, Jost

2014-07-01

Mass production of value-added molecules (including native and heterologous therapeutic proteins and enzymes) by plant cell culture has been demonstrated as an efficient alternative to classical technologies [i.e. natural harvest and chemical (semi)synthesis]. Numerous proof-of-concept studies have demonstrated the feasibility of scaling up plant cell culture-based processes (most notably to produce paclitaxel) and several commercial processes have been established so far. The choice of a suitable bioreactor design (or modification of an existing commercially available reactor) and the optimization of its internal environment have been proven as powerful tools toward successful mass production of desired molecules. This review highlights recent progress (mostly in the last 5 years) in hardware configuration and optimization of bioreactor culture conditions for suspended plant cells.

Modeling, numerical simulation and optimal control of plasma configuration evolution for the NET Tokamak and for the future generation of nuclear fusion

International Nuclear Information System (INIS)

Bourbon, F.

1993-03-01

The present thesis treats of the modeling, of the numerical simulation and equilibrium optimal control and configuration evolution of the plasma in a tokamak. In the first chapter, we establish the problem of equilibrium of the plasma by the finite elements method and a Newton algorithm. Then, we investigate the problem of equilibrium control: determination of currents in circuits of the tokamak to reach a given configuration. In the third chapter, we develop a model for evolution of the plasma configuration during a discharge. We solve this question by a Newton algorithm; with the fourth chapter, we treat the monitoring of plasma configuration evolution

Aerospace engineering design by systematic decomposition and multilevel optimization

Science.gov (United States)

Sobieszczanski-Sobieski, J.; Barthelemy, J. F. M.; Giles, G. L.

1984-01-01

A method for systematic analysis and optimization of large engineering systems, by decomposition of a large task into a set of smaller subtasks that is solved concurrently is described. The subtasks may be arranged in hierarchical levels. Analyses are carried out in each subtask using inputs received from other subtasks, and are followed by optimizations carried out from the bottom up. Each optimization at the lower levels is augmented by analysis of its sensitivity to the inputs received from other subtasks to account for the couplings among the subtasks in a formal manner. The analysis and optimization operations alternate iteratively until they converge to a system design whose performance is maximized with all constraints satisfied. The method, which is still under development, is tentatively validated by test cases in structural applications and an aircraft configuration optimization.

Momentum accumulation due to solar radiation torque, and reaction wheel sizing, with configuration optimization

Science.gov (United States)

Hablani, Hari B.

1993-01-01

This paper has a two-fold objective: determination of yearly momentum accumulation due to solar radiation pressure, and optimum reaction wheel sizing. The first objective is confronted while determining propellant consumption by the attitude control system over a spacecraft's lifetime. This, however, cannot be obtained from the daily momentum accumulation and treating that constant throughout the year, because the orientation of the solar arrays relative to the spacecraft changes over a wide range in a year, particularly if the spacecraft has two arrays, one normal and the other off-normal to different extent at different times to the sun rays. The paper first develops commands for the arrays for tracking the sun, the arrays articulated to earth-pointing spacecraft with two rotational degrees of freedom, and spacecraft in an arbitrary circular orbit. After developing expressions for solar radiation torque due to one or both arrays, arranged symmetrically or asymmetrically relative to the spacecraft bus, momentum accumulation over an orbit and then over a year are determined. The remainder of the paper is concerned with designing reaction wheel configurations. Four-, six-, and three-wheel configurations are considered, and for given torque and momentum requirements, their cant angles with the roll/yaw plane are optimized for minimum power consumption. Finally, their momentum and torque capacities are determined for one-wheel failure scenario, and six configurations are compared and contrasted.

A preliminary study on the optimal configuration and operating range of a “microgrid scale” air liquefaction plant for Liquid Air Energy Storage

International Nuclear Information System (INIS)

Borri, E.; Tafone, A.; Romagnoli, A.; Comodi, G.

2017-01-01

Highlights: • A liquefaction cycle for a microgrid scale Liquid Air Energy Storage is proposed. • Different liquefaction cycles are compared by means of parametric analysis. • The optimal configuration proposed is a Kapitza cycle with two stage compression. • The specific consumption of the optimal configuration is around 700 kW h/t. • Specific consumption reduces to 532 kW h/t if a pressurized phase separator is used. - Abstract: Liquid Air Energy Storage systems represent a sustainable solution to store energy. Although a lot of interest is dedicated to large scale systems (up to 300 tons per day), a small-scale Liquid Air Energy Storage can be used as energy storage as part of a microgrid and/or an energy distribution network. However, when scaling down the size of the system, the round trip efficiency decreases due to the low performance of the liquefaction process. In this paper a preliminary study on the optimal configuration for a microgrid scale liquefaction cycle (10 tons per 12 h) for a Liquid Air Energy Storage application is proposed in order to minimize the specific consumption. The Linde, Claude and Kapitza cycles are modelled and compared by means of a parametric analysis carried out with the software Aspen HYSYS. The results show that the two stages compression Kapitza cycle operating at 40 bar represents an optimal solution in terms of performance and cycle configuration resulting in a specific consumption of about 700 kW h/t. The analysis also shows that the implementation of a pressurized phase separator leads to a reduction of the specific consumption as high as 21% (≈550 kW h/t).

The irace package: Iterated racing for automatic algorithm configuration

Directory of Open Access Journals (Sweden)

Manuel López-Ibáñez

2016-01-01

Full Text Available Modern optimization algorithms typically require the setting of a large number of parameters to optimize their performance. The immediate goal of automatic algorithm configuration is to find, automatically, the best parameter settings of an optimizer. Ultimately, automatic algorithm configuration has the potential to lead to new design paradigms for optimization software. The irace package is a software package that implements a number of automatic configuration procedures. In particular, it offers iterated racing procedures, which have been used successfully to automatically configure various state-of-the-art algorithms. The iterated racing procedures implemented in irace include the iterated F-race algorithm and several extensions and improvements over it. In this paper, we describe the rationale underlying the iterated racing procedures and introduce a number of recent extensions. Among these, we introduce a restart mechanism to avoid premature convergence, the use of truncated sampling distributions to handle correctly parameter bounds, and an elitist racing procedure for ensuring that the best configurations returned are also those evaluated in the highest number of training instances. We experimentally evaluate the most recent version of irace and demonstrate with a number of example applications the use and potential of irace, in particular, and automatic algorithm configuration, in general.

Research on high-temperature heat receiver in concentrated solar radiation system

Directory of Open Access Journals (Sweden)

Estera Przenzak

2017-01-01

Full Text Available The article presents the results of experimental and computer simulations studies of the high temperature heat receiver working in the concentrated solar radiation system. In order to study the radiation absorption process and heat exchange, the two types of computer simulations were carried out. The first one was used to find the best location for absorber in the concentrating installation. Ray Tracing Monte Carlo (RTMC method in Trace Pro software was used to perform the optical simulations. The results of these simulations were presented in the form of the solar radiation distribution map and chart. The data obtained in RTMC simulations were used as a second type boundary conditions for Computational Fluid Dynamics (CFD simulations. These studies were used to optimize the internal geometry of the receiver and also to select the most effective flow parameters of the working medium. In order to validate the computer simulations, high temperature heat receiver was tested in experimental conditions. The article presents the results of experimental measurements in the form of temperature, radiation intensity and power graphs. The tests were performed for varied flow rate and receiver location. The experimental and computer simulation studies presented in this article allowed to optimize the configuration of concentrating and heat receiving system.

Topology optimization for biocatalytic microreactor configurations

DEFF Research Database (Denmark)

Pereira Rosinha, Ines; Gernaey, Krist; Woodley, John

2015-01-01

as a case study. The Evolutionary Structure Optimization (ESO) method is applied using an interface between Matlab® and the computational fluid dynamic simulation software ANSYS CFX®. In the case study, theESO method is applied to optimize the spatial distribution of immobilized enzyme inside a microreactor...

Maximum Profit Configurations of Commercial Engines

Directory of Open Access Journals (Sweden)

Yiran Chen

2011-06-01

Full Text Available An investigation of commercial engines with finite capacity low- and high-price economic subsystems and a generalized commodity transfer law [n ∝ Δ (P m] in commodity flow processes, in which effects of the price elasticities of supply and demand are introduced, is presented in this paper. Optimal cycle configurations of commercial engines for maximum profit are obtained by applying optimal control theory. In some special cases, the eventual state—market equilibrium—is solely determined by the initial conditions and the inherent characteristics of two subsystems; while the different ways of transfer affect the model in respects of the specific forms of the paths of prices and the instantaneous commodity flow, i.e., the optimal configuration.

NPIP: A skew line needle configuration optimization system for HDR brachytherapy

International Nuclear Information System (INIS)

Siauw, Timmy; Cunha, Adam; Berenson, Dmitry; Atamtürk, Alper; Hsu, I-Chow; Goldberg, Ken; Pouliot, Jean

2012-01-01

Purpose: In this study, the authors introduce skew line needle configurations for high dose rate (HDR) brachytherapy and needle planning by integer program (NPIP), a computational method for generating these configurations. NPIP generates needle configurations that are specific to the anatomy of the patient, avoid critical structures near the penile bulb and other healthy structures, and avoid needle collisions inside the body. Methods: NPIP consisted of three major components: a method for generating a set of candidate needles, a needle selection component that chose a candidate needle subset to be inserted, and a dose planner for verifying that the final needle configuration could meet dose objectives. NPIP was used to compute needle configurations for prostate cancer data sets from patients previously treated at our clinic. NPIP took two user-parameters: a number of candidate needles, and needle coverage radius, δ. The candidate needle set consisted of 5000 needles, and a range of δ values was used to compute different needle configurations for each patient. Dose plans were computed for each needle configuration. The number of needles generated and dosimetry were analyzed and compared to the physician implant. Results: NPIP computed at least one needle configuration for every patient that met dose objectives, avoided healthy structures and needle collisions, and used as many or fewer needles than standard practice. These needle configurations corresponded to a narrow range of δ values, which could be used as default values if this system is used in practice. The average end-to-end runtime for this implementation of NPIP was 286 s, but there was a wide variation from case to case. Conclusions: The authors have shown that NPIP can automatically generate skew line needle configurations with the aforementioned properties, and that given the correct input parameters, NPIP can generate needle configurations which meet dose objectives and use as many or fewer

Comparative study of receiver-side ghost wavefield attenuation on different marine acquisition configurations

Science.gov (United States)

Zhang, Hao; Liu, Qiancheng; Li, Hongyuan; Zhang, Yi

2018-04-01

In marine seismic exploration, the ghost energies (down-going waves), which arise from the reflection at the surface, are often treated as unwanted signals for data processing. The ghost wave fields interfere with the desired primary signals, leads to frequency notches and attenuation of low frequencies, which in turn downgrade the resolution of the recorded seismic data. There are two main categories of methods to solve the ghost or the so-called notch problem: the non-conventional acquisition configuration-based technique and a deghosting algorithm-based solution. The variable-depth streamer (VDS) acquisition solution is one of the most representative methods in the first category, which has become a popular solution for marine seismic acquisition to obtain broad data bandwidth. However, this approach is not as economic as the conventional constant depth streamer (CDS) acquisition, due to the precise control of the towing streamer. In addition, there are large quantities of conventionally-towed legacy data stored in the data library. Applying receiver deghosting to the CDS data thus becomes a more economical method. In theory, both types of data after deghosting should have the same bandwidth and S/N ratio, but in reality they are different. In this paper, we conduct a comparative study and evaluation to apply receiver deghosting to a set of real 2D marine data including both types of acquisition (CDS and VDS) corresponding to the same geology. The deghosting algorithm we employed is a self-sustained, inversion-based approach operated in the τ-p domain. This evaluation can help us to understand two questions: whether the VDS acquisition has more broadband characteristics compared to conventional CDS acquisition after deghosting, and whether we can achieve the identical or similar data quality (e.g., S/N ratio) through the proper deghosting algorithm for both types of data. The comparative results are illustrated and discussed.

Novel, cost-effective configurations of combined power plants for small-scale cogeneration from biomass: Feasibility study and performance optimization

International Nuclear Information System (INIS)

Amirante, Riccardo; Tamburrano, Paolo

2015-01-01

Highlights: • A cheap small combined cycle for cogeneration from biomass is proposed. • An optimization procedure is utilized to explore its potential. • Two configurations employing two different heat exchangers are considered. • The maximum electrical efficiency is 25%, the maximum overall efficiency is 70%. • The operation in load following mode is effective for both configurations. - Abstract: The aim of this paper is to demonstrate that, thanks to recent advances in designing micro steam expanders and gas to gas heat exchangers, the use of small combined cycles for simultaneous generation of heat and power from the external combustion of solid biomass and low quality biofuels is feasible. In particular, a novel typology of combined cycle that has the potential both to be cost-effective and to achieve a high level of efficiency is presented. In the small combined cycle proposed, a commercially available micro-steam turbine is utilized as the steam expander of the bottoming cycle, while the conventional microturbine of the topping cycle is replaced by a cheaper automotive turbocharger. The feasibility, reliability and availability of the required mechanical and thermal components are thoroughly investigated. In order to explore the potential of such a novel typology of power plant, an optimization procedure, based on a genetic algorithm combined with a computing code, is utilized to analyze the trade-off between the maximization of the electrical efficiency and the maximization of the thermal efficiency. Two design optimizations are performed: the first one makes use of the innovative “Immersed Particle Heat Exchanger”, whilst a nickel alloy heat exchanger is used in the other one. After selecting the optimum combination of the design parameters, the operation in load following mode is also assessed for both configurations

Design Optimization of Long-Span Cold-Formed Steel Portal Frames Accounting for Effect of Knee Brace Joint Configuration

Directory of Open Access Journals (Sweden)

Thanh Duoc Phan

2017-12-01

Full Text Available The application of cold-formed steel channel sections for portal frames becomes more popular for industrial and residential purposes. Experimental tests showed that such structures with long-span up to 20 m can be achieved when knee brace joints are included. In this paper, the influence of knee brace configuration on the optimum design of long-span cold-formed steel portal frames is investigated. The cold-formed steel portal frames are designed using Eurocode 3 under ultimate limit states. A novel method in handling design constraints integrated with genetic algorithm is proposed for searching the optimum design of cold-formed steel portal frames. The result showed that the proposed routine for design optimization effectively searched the near global optimum solution with the computational time is approximate 50% faster than methods being popularly used in literature. The optimum configuration for knee brace joint can reduce the section size of rafter and so the lighter frame could be obtained especially for long-span portal frame. The minimum weight of main frame obtained from optimization process is approximate 19.72% lighter than a Benchmark Frame used in the full-scale experimental test.

Configuring Airspace Sectors with Approximate Dynamic Programming

Science.gov (United States)

Bloem, Michael; Gupta, Pramod

2010-01-01

In response to changing traffic and staffing conditions, supervisors dynamically configure airspace sectors by assigning them to control positions. A finite horizon airspace sector configuration problem models this supervisor decision. The problem is to select an airspace configuration at each time step while considering a workload cost, a reconfiguration cost, and a constraint on the number of control positions at each time step. Three algorithms for this problem are proposed and evaluated: a myopic heuristic, an exact dynamic programming algorithm, and a rollouts approximate dynamic programming algorithm. On problem instances from current operations with only dozens of possible configurations, an exact dynamic programming solution gives the optimal cost value. The rollouts algorithm achieves costs within 2% of optimal for these instances, on average. For larger problem instances that are representative of future operations and have thousands of possible configurations, excessive computation time prohibits the use of exact dynamic programming. On such problem instances, the rollouts algorithm reduces the cost achieved by the heuristic by more than 15% on average with an acceptable computation time.

Nonlinear Multiuser Receiver for Optimized Chaos-Based DS-CDMA Systems

Directory of Open Access Journals (Sweden)

S. Shaerbaf

2011-09-01

Full Text Available Chaos based communications have drawn increasing attention over the past years. Chaotic signals are derived from non-linear dynamic systems. They are aperiodic, broadband and deterministic signals that appear random in the time domain. Because of these properties, chaotic signals have been proposed to generate spreading sequences for wide-band secure communication recently. Like conventional DS-CDMA systems, chaos-based CDMA systems suffer from multi-user interference (MUI due to other users transmitting in the cell. In this paper, we propose a novel method based on radial basis function (RBF for both blind and non-blind multiuser detection in chaos-based DS-CDMA systems. We also propose a new method for optimizing generation of binary chaotic sequences using Genetic Algorithm. Simulation results show that our proposed nonlinear receiver with optimized chaotic sequences outperforms in comparison to other conventional detectors such as a single-user detector, decorrelating detector and minimum mean square error detector, particularly for under-loaded CDMA condition, which the number of active users is less than processing gain.

The impact of x-ray tube configuration on the eye lens and extremity doses received by cardiologists in electrophysiology room

International Nuclear Information System (INIS)

Domienik, J; Zmyślony, M; Bissinger, A

2014-01-01

The aim of the study was to analyse the influence of the x-ray tube configuration on the radiation doses to eye lens and extremities of cardiologists performing pacemaker implantation procedures in electrophysiology laboratory. The measurements were performed on one, widely used, portable C-arm system, first with x-ray tube mounted above the patient table and image intensifier below it and then on a reinstalled (but essentially the same) system with under-table x-ray tube configuration. Thermoluminescent dosimeters, placed in various positions near the eye lens, on the hands and ankle, were used during every procedure. The comparison of doses received by cardiologists after changing the x-ray tube configuration from over- to under-table shows statistically significant dose reduction (p < 0.009) for the eye lens closest to the x-ray tube, left finger, left wrist, while for the ankle a dose increase is observed. The corresponding over- to under-table x-ray tube median dose ratios are 4.1 for the right eye, 4.8 for the left finger, 3.0 for left wrist and, finally, 0.13 for the right ankle. Systems with under-table x-ray tube are preferable from a radiation protection point of view. The observed significant increase in doses to the legs should be partially compensated by the use of a protective lead curtain. (note)

Optimal power allocation of a single transmitter-multiple receivers channel in a cognitive sensor network

KAUST Repository

Ayala Solares, Jose Roberto; Rezki, Zouheir; Alouini, Mohamed-Slim

2012-01-01

The optimal transmit power of a wireless sensor network with one transmitter and multiple receivers in a cognitive radio environment while satisfying independent peak, independent average, sum of peak and sum of average transmission rate constraints

Optimizing the order processing of customized products using product configuration

DEFF Research Database (Denmark)

Hvam, Lars; Bonev, Martin; Denkena, B.

2011-01-01

. Product configuration based on integrated modular product structure and product family architecture has been recognized as an effective means for implementing mass customization. In order to evaluate the effects of product configuration on order processing, a study has been conducted by the Department...... and its benefits for the order processing have been evaluated....

Optimized readout configuration for PIXE spectrometers based on Silicon Drift Detectors: Architecture and performance

International Nuclear Information System (INIS)

Alberti, R.; Grassi, N.; Guazzoni, C.; Klatka, T.

2009-01-01

An optimized readout configuration based on a charge preamplifier with pulsed-reset has been designed for Silicon Drift Detectors (SDDs) to be used in Particle Induced X-ray Emission (PIXE) measurements. The customized readout electronics is able to manage the large pulses originated by the protons backscattered from the target material that would otherwise cause significant degradation of X-ray spectra and marked increase in dead time. In this way, the excellent performance of SDDs can be exploited in high-quality proton-induced spectroscopy of low- and medium-energy X-rays. This paper describes the designed readout architecture and the performance characterization carried out in a PIXE setup with MeV proton beams.

Injection and temporary capture of a charged particle beam in an open magnetic configuration. Optimization of the configuration. Case of cylindrical symmetry: A mirror machine

International Nuclear Information System (INIS)

Capdequi-Peyranere, P.

1966-12-01

A study has been made of a new method of transverse injection of charged particles into a magnetic mirror configuration. This injection scheme permits the penetration and temporary capture by non-adiabatic effect of a particle beam of approximately 1 cm 2 cross-section. A theoretical study of the injection and capture is made in the approximation that space charge is negligible. The original programs for IBM 7094 computer calculations are described; these programs were used to obtain an optimization of the configuration. The results of a statistical numerical study of the optimum configuration are then given. This study indicates that, if the energy of the particles of the beam is about 1 per cent greater than a minimum penetration energy, the entire beam can be captured with an average capture length of 100 meters (50 reflections between the two mirrors). If the energy is about 4 per cent greater than the minimum penetration energy, the capture length is reduced to 40 meters. We have studied the distribution of energy transverse and longitudinal with the magnetic field for the population of captured particles. For the cases of injected molecular hydrogen ions or heavy CH 4 + ions, a study is made of the capture time of protons resulting from the dissociation of the ions by collisions with the neutral gas. Finally, we describe a model experiment using electrons designed to provide an experimental verification of the capture of the primary beam. (author) [fr

Design issues for optimum solar cell configuration

Science.gov (United States)

Kumar, Atul; Thakur, Ajay D.

2018-05-01

A computer based simulation of solar cell structure is performed to study the optimization of pn junction configuration for photovoltaic action. The fundamental aspects of photovoltaic action viz, absorption, separation collection, and their dependence on material properties and deatails of device structures is discussed. Using SCAPS 1D we have simulated the ideal pn junction and shown the effect of band offset and carrier densities on solar cell performance. The optimum configuration can be achieved by optimizing transport of carriers in pn junction under effect of field dependent recombination (tunneling) and density dependent recombination (SRH, Auger) mechanisms.

Quasi-isodynamic configuration with large number of periods

International Nuclear Information System (INIS)

Shafranov, V.D.; Isaev, M.Yu.; Mikhailov, M.I.; Subbotin, A.A.; Cooper, W.A.; Kalyuzhnyj, V.N.; Kasilov, S.V.; Nemov, V.V.; Kernbichler, W.; Nuehrenberg, C.; Nuehrenberg, J.; Zille, R.

2005-01-01

It has been previously reported that quasi-isodynamic (qi) stellarators with poloidal direction of the contours of B on magnetic surface can exhibit very good fast- particle collisionless confinement. In addition, approaching the quasi-isodynamicity condition leads to diminished neoclassical transport and small bootstrap current. The calculations of local-mode stability show that there is a tendency toward an increasing beta limit with increasing number of periods. The consideration of the quasi-helically symmetric systems has demonstrated that with increasing aspect ratio (and number of periods) the optimized configuration approaches the straight symmetric counterpart, for which the optimal parameters and highest beta values were found by optimization of the boundary magnetic surface cross-section. The qi system considered here with zero net toroidal current do not have a symmetric analogue in the limit of large aspect ratio and finite rotational transform. Thus, it is not clear whether some invariant structure of the configuration period exists in the limit of negligible toroidal effect and what are the best possible parameters for it. In the present paper the results of an optimization of the configuration with N = 12 number of periods are presented. Such properties as fast-particle confinement, effective ripple, structural factor of bootstrap current and MHD stability are considered. It is shown that MHD stability limit here is larger than in configurations with smaller number of periods considered earlier. Nevertheless, the toroidal effect in this configuration is still significant so that a simple increase of the number of periods and proportional growth of aspect ratio do not conserve favourable neoclassical transport and ideal local-mode stability properties. (author)

HIGH-EFFICIENCY INFRARED RECEIVER

Directory of Open Access Journals (Sweden)

A. K. Esman

2016-01-01

Full Text Available Recent research and development show promising use of high-performance solid-state receivers of the electromagnetic radiation. These receivers are based on the low-barrier Schottky diodes. The approach to the design of the receivers on the basis of delta-doped low-barrier Schottky diodes with beam leads without bias is especially actively developing because for uncooled receivers of the microwave radiation these diodes have virtually no competition. The purpose of this work is to improve the main parameters and characteristics that determine the practical relevance of the receivers of mid-infrared electromagnetic radiation at the operating room temperature by modifying the electrodes configuration of the diode and optimizing the distance between them. Proposed original design solution of the integrated receiver of mid-infrared radiation on the basis of the low-barrier Schottky diodes with beam leads allows to effectively adjust its main parameters and characteristics. Simulation of the electromagnetic characteristics of the proposed receiver by using the software package HFSS with the basic algorithm of a finite element method which implemented to calculate the behavior of electromagnetic fields on an arbitrary geometry with a predetermined material properties have shown that when the inner parts of the electrodes of the low-barrier Schottky diode is performed in the concentric elliptical convex-concave shape, it can be reduce the reflection losses to -57.75 dB and the standing wave ratio to 1.003 while increasing the directivity up to 23 at a wavelength of 6.09 μm. At this time, the rounded radii of the inner parts of the anode and cathode electrodes are equal 212 nm and 318 nm respectively and the gap setting between them is 106 nm. These parameters will improve the efficiency of the developed infrared optical-promising and electronic equipment for various purposes intended for work in the mid-infrared wavelength range. 

Nash Game Model for Optimizing Market Strategies, Configuration of Platform Products in a Vendor Managed Inventory (VMI) Supply Chain for a Product Family

NARCIS (Netherlands)

Y. Yu (Yugang); G.Q. Huang (George)

2009-01-01

textabstractThis paper discusses how a manufacturer and its retailers interact with each other to optimize their product marketing strategies, platform product configuration and inventory policies in a VMI (Vendor Managed Inventory) supply chain. The manufacturer procures raw materials from multiple

Multi-GPU configuration of 4D intensity modulated radiation therapy inverse planning using global optimization

Science.gov (United States)

Hagan, Aaron; Sawant, Amit; Folkerts, Michael; Modiri, Arezoo

2018-01-01

We report on the design, implementation and characterization of a multi-graphic processing unit (GPU) computational platform for higher-order optimization in radiotherapy treatment planning. In collaboration with a commercial vendor (Varian Medical Systems, Palo Alto, CA), a research prototype GPU-enabled Eclipse (V13.6) workstation was configured. The hardware consisted of dual 8-core Xeon processors, 256 GB RAM and four NVIDIA Tesla K80 general purpose GPUs. We demonstrate the utility of this platform for large radiotherapy optimization problems through the development and characterization of a parallelized particle swarm optimization (PSO) four dimensional (4D) intensity modulated radiation therapy (IMRT) technique. The PSO engine was coupled to the Eclipse treatment planning system via a vendor-provided scripting interface. Specific challenges addressed in this implementation were (i) data management and (ii) non-uniform memory access (NUMA). For the former, we alternated between parameters over which the computation process was parallelized. For the latter, we reduced the amount of data required to be transferred over the NUMA bridge. The datasets examined in this study were approximately 300 GB in size, including 4D computed tomography images, anatomical structure contours and dose deposition matrices. For evaluation, we created a 4D-IMRT treatment plan for one lung cancer patient and analyzed computation speed while varying several parameters (number of respiratory phases, GPUs, PSO particles, and data matrix sizes). The optimized 4D-IMRT plan enhanced sparing of organs at risk by an average reduction of 26% in maximum dose, compared to the clinical optimized IMRT plan, where the internal target volume was used. We validated our computation time analyses in two additional cases. The computation speed in our implementation did not monotonically increase with the number of GPUs. The optimal number of GPUs (five, in our study) is directly related to the

Observed benefits from product configuration systems

DEFF Research Database (Denmark)

Hvam, Lars; Haug, Anders; Mortensen, Niels Henrik

2013-01-01

This article presents a study of the benefits obtained from applying product configuration systems based on a case study in four industry companies. The impacts are described according to main objectives in literature for imple-menting product configuration systems: lead time in the specification...... affected by the use of product configu-ration systems e.g. increased sales, decrease in the number of SKU's, improved ability to introduce new products, and cost reductions.......This article presents a study of the benefits obtained from applying product configuration systems based on a case study in four industry companies. The impacts are described according to main objectives in literature for imple-menting product configuration systems: lead time in the specification...... processes, on-time delivery of the specifica-tions, and resource consumption for making specifications, quality of specifications, optimization of products and services, and other observations. The purpose of the study is partly to identify specific impacts observed from implementing product configuration...

Investigation and optimization of the magnetic field configuration in high-power impulse magnetron sputtering

International Nuclear Information System (INIS)

Yu, He; Meng, Liang; Szott, Matthew M; Meister, Jack T; Cho, Tae S; Ruzic, David N

2013-01-01

An effort to optimize the magnetic field configuration specifically for high-power impulse magnetron sputtering (HiPIMS) was made. Magnetic field configurations with different field strengths, race track widths and race track patterns were designed using COMSOL. Their influence on HiPIMS plasma properties was investigated using a 36 cm diameter copper target. The I–V discharge characteristics were measured. The temporal evolution of electron temperature (T e ) and density (n e ) was studied employing a triple Langmuir probe, which was also scanned in the whole discharge region to characterize the plasma distribution and transport. Based on the studies, a closed path for electrons to drift along was still essential in HiPIMS in order to efficiently confine electrons and achieve a high pulse current. Very dense plasmas (10 19 –10 20 m −3 ) were generated in front of the race tracks during the pulse, and expanded downstream afterwards. As the magnetic field strength increased from 200 to 800 G, the expansion became faster and less isotropic, i.e. more directional toward the substrate. The electric potential distribution accounted for these effects. Varied race track widths and patterns altered the plasma distribution from the target to the substrate. A spiral-shaped magnetic field design was able to produce superior plasma uniformity on the substrate in addition to improved target utilization. (paper)

Learning optimal embedded cascades.

Science.gov (United States)

Saberian, Mohammad Javad; Vasconcelos, Nuno

2012-10-01

The problem of automatic and optimal design of embedded object detector cascades is considered. Two main challenges are identified: optimization of the cascade configuration and optimization of individual cascade stages, so as to achieve the best tradeoff between classification accuracy and speed, under a detection rate constraint. Two novel boosting algorithms are proposed to address these problems. The first, RCBoost, formulates boosting as a constrained optimization problem which is solved with a barrier penalty method. The constraint is the target detection rate, which is met at all iterations of the boosting process. This enables the design of embedded cascades of known configuration without extensive cross validation or heuristics. The second, ECBoost, searches over cascade configurations to achieve the optimal tradeoff between classification risk and speed. The two algorithms are combined into an overall boosting procedure, RCECBoost, which optimizes both the cascade configuration and its stages under a detection rate constraint, in a fully automated manner. Extensive experiments in face, car, pedestrian, and panda detection show that the resulting detectors achieve an accuracy versus speed tradeoff superior to those of previous methods.

Different electrode configurations to optimize performance of multi-electrode microbial fuel cells for generating power or treating domestic wastewater

KAUST Repository

Ahn, Yongtae

2014-03-01

Scaling-up of microbial fuel cells (MFCs) for practical applications requires compact, multiple-electrode designs. Two possible configurations are a separator electrode assembly (SEA) or closely spaced electrodes (SPA) that lack a separator. It is shown here that the optimal configuration depends on whether the goal is power production or rate of wastewater treatment. SEA MFCs produced a 16% higher maximum power density (328 ± 11 mW m-2) than SPA MFCs (282 ± 29 mW m-2), and higher coulombic efficiencies (SEAs, 9-31%; SPAs, 2-23%) with domestic wastewater. However, treatment was accomplished in only 12 h with the SPA MFC, compared to 36 h with the SEA configuration. Ohmic resistance was not a main factor in performance as this component contributed only 4-7% of the total internal resistance. Transport simulations indicated that hindered oxygen diffusion into the SEA reactor was the primary reason for the increased treatment time. However, a reduction in the overall rate of substrate diffusion also may contribute to the long treatment time with the SEA reactor. These results suggest that SEA designs can more effectively capture energy from wastewater, but SPA configurations will be superior in terms of treatment efficiency due to a greatly reduced time needed for treatment. © 2013 Elsevier B.V. All rights reserved.

Different electrode configurations to optimize performance of multi-electrode microbial fuel cells for generating power or treating domestic wastewater

KAUST Repository

Ahn, Yongtae; Hatzell, Marta C.; Zhang, Fang; Logan, Bruce E.

2014-01-01

Scaling-up of microbial fuel cells (MFCs) for practical applications requires compact, multiple-electrode designs. Two possible configurations are a separator electrode assembly (SEA) or closely spaced electrodes (SPA) that lack a separator. It is shown here that the optimal configuration depends on whether the goal is power production or rate of wastewater treatment. SEA MFCs produced a 16% higher maximum power density (328 ± 11 mW m-2) than SPA MFCs (282 ± 29 mW m-2), and higher coulombic efficiencies (SEAs, 9-31%; SPAs, 2-23%) with domestic wastewater. However, treatment was accomplished in only 12 h with the SPA MFC, compared to 36 h with the SEA configuration. Ohmic resistance was not a main factor in performance as this component contributed only 4-7% of the total internal resistance. Transport simulations indicated that hindered oxygen diffusion into the SEA reactor was the primary reason for the increased treatment time. However, a reduction in the overall rate of substrate diffusion also may contribute to the long treatment time with the SEA reactor. These results suggest that SEA designs can more effectively capture energy from wastewater, but SPA configurations will be superior in terms of treatment efficiency due to a greatly reduced time needed for treatment. © 2013 Elsevier B.V. All rights reserved.

Solar energy receiver

Science.gov (United States)

Schwartz, Jacob

1978-01-01

An improved long-life design for solar energy receivers provides for greatly reduced thermally induced stress and permits the utilization of less expensive heat exchanger materials while maintaining receiver efficiencies in excess of 85% without undue expenditure of energy to circulate the working fluid. In one embodiment, the flow index for the receiver is first set as close as practical to a value such that the Graetz number yields the optimal heat transfer coefficient per unit of pumping energy, in this case, 6. The convective index for the receiver is then set as closely as practical to two times the flow index so as to obtain optimal efficiency per unit mass of material.

Experimental design approach to the process parameter optimization for laser welding of martensitic stainless steels in a constrained overlap configuration

Science.gov (United States)

Khan, M. M. A.; Romoli, L.; Fiaschi, M.; Dini, G.; Sarri, F.

2011-02-01

This paper presents an experimental design approach to process parameter optimization for the laser welding of martensitic AISI 416 and AISI 440FSe stainless steels in a constrained overlap configuration in which outer shell was 0.55 mm thick. To determine the optimal laser-welding parameters, a set of mathematical models were developed relating welding parameters to each of the weld characteristics. These were validated both statistically and experimentally. The quality criteria set for the weld to determine optimal parameters were the minimization of weld width and the maximization of weld penetration depth, resistance length and shearing force. Laser power and welding speed in the range 855-930 W and 4.50-4.65 m/min, respectively, with a fiber diameter of 300 μm were identified as the optimal set of process parameters. However, the laser power and welding speed can be reduced to 800-840 W and increased to 4.75-5.37 m/min, respectively, to obtain stronger and better welds.

On the optimal identification of tag sets in time-constrained RFID configurations.

Science.gov (United States)

Vales-Alonso, Javier; Bueno-Delgado, María Victoria; Egea-López, Esteban; Alcaraz, Juan José; Pérez-Mañogil, Juan Manuel

2011-01-01

In Radio Frequency Identification facilities the identification delay of a set of tags is mainly caused by the random access nature of the reading protocol, yielding a random identification time of the set of tags. In this paper, the cumulative distribution function of the identification time is evaluated using a discrete time Markov chain for single-set time-constrained passive RFID systems, namely those ones where a single group of tags is assumed to be in the reading area and only for a bounded time (sojourn time) before leaving. In these scenarios some tags in a set may leave the reader coverage area unidentified. The probability of this event is obtained from the cumulative distribution function of the identification time as a function of the sojourn time. This result provides a suitable criterion to minimize the probability of losing tags. Besides, an identification strategy based on splitting the set of tags in smaller subsets is also considered. Results demonstrate that there are optimal splitting configurations that reduce the overall identification time while keeping the same probability of losing tags.

Collaborative Systems Driven Aircraft Configuration Design Optimization

OpenAIRE

Shiva Prakasha, Prajwal; Ciampa, Pier Davide; Nagel, Björn

2016-01-01

A Collaborative, Inside-Out Aircraft Design approach is presented in this paper. An approach using physics based analysis to evaluate the correlations between the airframe design, as well as sub-systems integration from the early design process, and to exploit the synergies within a simultaneous optimization process. Further, the disciplinary analysis modules involved in the optimization task are located in different organization. Hence, the Airframe and Subsystem design tools are integrated ...

Projected configuration of a coal-fired district heating source on the basis of comparative technical-economical optimization analysis

Directory of Open Access Journals (Sweden)

Tańczuk Mariusz

2017-01-01

Full Text Available District heating technologies should be efficient, effective and environmentally friendly. The majority of the communal heating systems in Poland produce district hot water in coal-fired boilers. A large number of them are considerably worn out, low-efficient in the summer time and will not comply with forthcoming regulations. One of the possible solution for such plants is repowering with new CHP systems or new boilers fuelled with fuels alternative to coal. Optimisation analysis of the target configuration of municipal heat generating plant is analysed in the paper. The work concerns repowering the existing conventional heat generating plant according to eight different scenarios of the plant configuration meeting technical and environmental requirements forecasted for the year of 2035. The maximum demand for heat of the system supplied by the plant is 185 MW. Taking into account different technical configurations on one side, and different energy and fuel prices on the other side, the comparative cost-benefits analysis of the assumed scenarios has been made. The basic economical index NPV (net present value has been derived for each analysed scenario and the results have been compared and discussed. It was also claimed that the scenario with CHP based on ICE engines is optimal.

Projected configuration of a coal-fired district heating source on the basis of comparative technical-economical optimization analysis

Science.gov (United States)

Tańczuk, Mariusz; Radziewicz, Wojciech; Olszewski, Eligiusz; Skorek, Janusz

2017-10-01

District heating technologies should be efficient, effective and environmentally friendly. The majority of the communal heating systems in Poland produce district hot water in coal-fired boilers. A large number of them are considerably worn out, low-efficient in the summer time and will not comply with forthcoming regulations. One of the possible solution for such plants is repowering with new CHP systems or new boilers fuelled with fuels alternative to coal. Optimisation analysis of the target configuration of municipal heat generating plant is analysed in the paper. The work concerns repowering the existing conventional heat generating plant according to eight different scenarios of the plant configuration meeting technical and environmental requirements forecasted for the year of 2035. The maximum demand for heat of the system supplied by the plant is 185 MW. Taking into account different technical configurations on one side, and different energy and fuel prices on the other side, the comparative cost-benefits analysis of the assumed scenarios has been made. The basic economical index NPV (net present value) has been derived for each analysed scenario and the results have been compared and discussed. It was also claimed that the scenario with CHP based on ICE engines is optimal.

Study of an optimal configuration of a transmutation reactor based on a low-aspect-ratio tokamak

Energy Technology Data Exchange (ETDEWEB)

Hong, Bong Guen, E-mail: bghong@jbnu.ac.kr [Department of Quantum System Engineering, Chonbuk National University, 567 Baekje-daero, Jeonju, Jeonbuk 54896 (Korea, Republic of); Kim, Hoseok [Department of Applied Plasma Engineering, Chonbuk National University, 567 Baekje-daero, Jeonju, Jeonbuk 54896 (Korea, Republic of)

2016-11-15

Highlights: • Optimum configuration of a transmutation reactor based on a low aspect ratio tokamak was found. • Inboard and outboard radial build are determined by plasma physics, engineering and neutronics constraints. • Radial build and equilibrium fuel cycle play a major role in determining the transmutation characteristics. - Abstract: We determine the optimal configuration of a transmutation reactor based on a low-aspect-ratio tokamak. For self-consistent determination of the radial build of the reactor components, we couple a tokamak systems analysis with a radiation transport calculation. The inboard radial build of the reactor components is obtained from plasma physics and engineering constraints, while outboard radial builds are mainly determined by constraints on neutron multiplication, the tritium-breeding ratio, and the power density. We show that the breeding blanket model has an effect on the radial build of a transmutation blanket. A burn cycle has to be determined to keep the fast neutron fluence plasma-facing material below its radiation damage limit. We show that the radial build of the transmutation reactor components and the equilibrium fuel cycle play a major role in determining the transmutation characteristics.

Modeling the planar configuration of extraordinary magnetoresistance

International Nuclear Information System (INIS)

El-Ahmar, S; Pozniak, A A

2015-01-01

Recently the planar version of the extraordinary magnetoresistance (EMR) magnetic field sensor has been constructed and verified in practice. Planar configuration of the EMR device gives many technological advantages, it is simpler than the classic and allows one to build the sensor using electric materials of the new type (such as graphene or topological insulators) much easier. In this work the planar configuration of the EMR sensor is investigated by performing computational simulations using the finite element method (FEM). The computational comparison of the planar and classic configurations of EMR is presented using three-dimensional models. Various variants of the geometry of EMR sensor components are pondered and compared in the planar and classic version. Size of the metal overlap is considered for sensor optimization as well as various semiconductor-metal contact resistance dependences of the EMR signal. Based on computational simulations, a method for optimal placement of electric terminals in a planar EMR device is proposed. (paper)

Fixed-Point Configurable Hardware Components

Directory of Open Access Journals (Sweden)

Rocher Romuald

2006-01-01

Full Text Available To reduce the gap between the VLSI technology capability and the designer productivity, design reuse based on IP (intellectual properties is commonly used. In terms of arithmetic accuracy, the generated architecture can generally only be configured through the input and output word lengths. In this paper, a new kind of method to optimize fixed-point arithmetic IP has been proposed. The architecture cost is minimized under accuracy constraints defined by the user. Our approach allows exploring the fixed-point search space and the algorithm-level search space to select the optimized structure and fixed-point specification. To significantly reduce the optimization and design times, analytical models are used for the fixed-point optimization process.

Communicating knowledge: Making embedded configuration work

DEFF Research Database (Denmark)

Oddsson, Gudmundur Valur; Hvam, Lars

2007-01-01

A lot of systems are assembled from near-independent mechatronic subsystems that have to be configured to match each other. An example of such systems are e.g. home entertainment systems, where TV, DVD and Receiver are matched to form an overall system, and compilation of pumps and controllers...... to form fresh water supply systems. Sometimes an external knowledge system keeps track of how each subsystem has to be configured, but the actual configuration is often done manually. Installing and maintaining those kinds of systems can be a tedious task and often requires repetitive labour. The idea...... is to “split-up” the product knowledge and encapsulate it into each subsystem. Then, when the subsystems are assembled, the configuration of each subsystem can either be done automatically or with minimum input. The concept could be called: embedded configuration. This article will try to connect three aspects...

Optimization of a recompression supercritical carbon dioxide cycle for an innovative central receiver solar power plant

International Nuclear Information System (INIS)

Reyes-Belmonte, M.A.; Sebastián, A.; Romero, M.; González-Aguilar, J.

2016-01-01

Peculiar thermodynamic properties of carbon dioxide (CO 2 ) when it is held at or above its critical condition (stated as supercritical CO 2 or sCO 2 ) have attracted the attention of many researchers. Its excellent thermophysical properties at medium-to-moderate temperature range have made it to be considered as the alternative working fluid for next power plant generation. Among those applications, future nuclear reactors, solar concentrated thermal energy or waste energy recovery have been shown as the most promising ones. In this paper, a recompression sCO 2 cycle for a solar central particles receiver application has been optimized, observing net cycle efficiency close to 50%. However, small changes on cycle parameters such as working temperatures, recuperators efficiencies or mass flow distribution between low and high temperature recuperators were found to drastically modify system overall efficiency. In order to mitigate these uncertainties, an optimization analysis based on recuperators effectiveness definition was performed observing that cycle efficiency could lie among 40%–50% for medium-to-moderate temperature range of the studied application (630 °C–680 °C). Due to the lack of maturity of current sCO 2 technologies and no power production scale demonstrators, cycle boundary conditions based on the solar application and a detailed literature review were chosen. - Highlights: • Mathematical modelling description for recompression sCO 2 cycle. • Split fraction and recuperators effectiveness effect into sCO 2 cycle performance. • Optimization methodology of sCO 2 cycle for an innovative solar central receiver. • Power generation using particles central receiver.

Optimization of multi-objective micro-grid based on improved particle swarm optimization algorithm

Science.gov (United States)

Zhang, Jian; Gan, Yang

2018-04-01

The paper presents a multi-objective optimal configuration model for independent micro-grid with the aim of economy and environmental protection. The Pareto solution set can be obtained by solving the multi-objective optimization configuration model of micro-grid with the improved particle swarm algorithm. The feasibility of the improved particle swarm optimization algorithm for multi-objective model is verified, which provides an important reference for multi-objective optimization of independent micro-grid.

Heat receivers for solar dynamic space power systems

Science.gov (United States)

Perez-Davis, Marla Esther

A review of state-of-the-art technology is presented and discussed for phase change materials. Some of the advanced solar dynamic designs developed as part of the Advanced Heat Receiver Conceptual Design Study performed for LeRC are discussed. The heat receivers are analyzed and several recommendations are proposed, including two new concepts. The first concept evaluated the effect of tube geometries inside the heat receiver. It was found that a triangular configuration would provide better heat transfer to the working fluid, although not necessarily with a reduction in receiver size. A sensible heat receiver considered in this study uses vapor grown graphite fiber-carbon (VGCF/C) composite as the thermal storage media and was designed for a 7 kW Brayton engine. The proposed heat receiver stores the required energy to power the system during eclipse in the VGCF/C composite. The heat receiver analysis was conducted through the Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA) software package. The proposed heat receiver compares well with other latent and advanced sensible heat receivers while avoiding the problems associated with latent heat storage salts and liquid metal heat pipes. The weight and size of the system can be optimized by changes in geometry and technology advances for this new material. In addition to the new concepts, the effect of atomic oxygen on several materials is reviewed. A test was conducted for atomic oxygen attack on boron nitride, which experienced a negligible mass loss when exposed to an atomic oxygen fluence of 5 x 10 exp 21 atoms/sq cm. This material could be used to substitute the graphite aperture plate of the heat receiver.

Sizing and Optimization for Hybrid Central in South Algeria Based on Three Different Generators

Directory of Open Access Journals (Sweden)

Chouaib Ammari

2017-11-01

Full Text Available In this paper, we will size an optimum hybrid central content three different generators, two on renewable energy (solar photovoltaic and wind power and two nonrenewable (diesel generator and storage system because the new central generator has started to consider the green power technology in order for best future to the world, this central will use all the green power resource available and distributes energy to a small isolated village in southwest of Algeria named “Timiaouine”. The consumption of this village estimated with detailed in two season; season low consumption (winter and high consumption (summer, the hybrid central will be optimized by program Hybrid Optimization Model for Electric Renewable (HOMER PRO, this program will simulate in two configuration, the first with storage system, the second without storage system and in the end the program HOMER PRO will choose the best configuration which is the mixture of both economic and ecologic configurations, this central warrants the energetic continuity of village. Article History: Received May 18th 2017; Received in revised form July 17th 2017; Accepted Sept 3rd 2017; Available online How to Cite This Article: Ammari, C., Hamouda,M., and Makhloufi,S. (2017 Sizing and Optimization for Hybrid Central in South Algeria Based on Three Different Generators. International Journal of Renewable Energy Development, 6(3, 263-272. http://doi.org/10.14710/ijred.6.3.263-272

Configuration affects parallel stent grafting results.

Science.gov (United States)

Tanious, Adam; Wooster, Mathew; Armstrong, Paul A; Zwiebel, Bruce; Grundy, Shane; Back, Martin R; Shames, Murray L

2018-05-01

A number of adjunctive "off-the-shelf" procedures have been described to treat complex aortic diseases. Our goal was to evaluate parallel stent graft configurations and to determine an optimal formula for these procedures. This is a retrospective review of all patients at a single medical center treated with parallel stent grafts from January 2010 to September 2015. Outcomes were evaluated on the basis of parallel graft orientation, type, and main body device. Primary end points included parallel stent graft compromise and overall endovascular aneurysm repair (EVAR) compromise. There were 78 patients treated with a total of 144 parallel stents for a variety of pathologic processes. There was a significant correlation between main body oversizing and snorkel compromise (P = .0195) and overall procedural complication (P = .0019) but not with endoleak rates. Patients were organized into the following oversizing groups for further analysis: 0% to 10%, 10% to 20%, and >20%. Those oversized into the 0% to 10% group had the highest rate of overall EVAR complication (73%; P = .0003). There were no significant correlations between any one particular configuration and overall procedural complication. There was also no significant correlation between total number of parallel stents employed and overall complication. Composite EVAR configuration had no significant correlation with individual snorkel compromise, endoleak, or overall EVAR or procedural complication. The configuration most prone to individual snorkel compromise and overall EVAR complication was a four-stent configuration with two stents in an antegrade position and two stents in a retrograde position (60% complication rate). The configuration most prone to endoleak was one or two stents in retrograde position (33% endoleak rate), followed by three stents in an all-antegrade position (25%). There was a significant correlation between individual stent configuration and stent compromise (P = .0385), with 31

Viscous Design of TCA Configuration

Science.gov (United States)

Krist, Steven E.; Bauer, Steven X. S.; Campbell, Richard L.

1999-01-01

The goal in this effort is to redesign the baseline TCA configuration for improved performance at both supersonic and transonic cruise. Viscous analyses are conducted with OVERFLOW, a Navier-Stokes code for overset grids, using PEGSUS to compute the interpolations between overset grids. Viscous designs are conducted with OVERDISC, a script which couples OVERFLOW with the Constrained Direct Iterative Surface Curvature (CDISC) inverse design method. The successful execution of any computational fluid dynamics (CFD) based aerodynamic design method for complex configurations requires an efficient method for regenerating the computational grids to account for modifications to the configuration shape. The first section of this presentation deals with the automated regridding procedure used to generate overset grids for the fuselage/wing/diverter/nacelle configurations analysed in this effort. The second section outlines the procedures utilized to conduct OVERDISC inverse designs. The third section briefly covers the work conducted by Dick Campbell, in which a dual-point design at Mach 2.4 and 0.9 was attempted using OVERDISC; the initial configuration from which this design effort was started is an early version of the optimized shape for the TCA configuration developed by the Boeing Commercial Airplane Group (BCAG), which eventually evolved into the NCV design. The final section presents results from application of the Natural Flow Wing design philosophy to the TCA configuration.

The Multipoint Global Shape Optimization of Flying Configuration with Movable Leading Edges Flaps

Directory of Open Access Journals (Sweden)

Adriana NASTASE

2012-12-01

Full Text Available The aerodynamical global optimized (GO shape of flying configuration (FC, at two cruising Mach numbers, can be realized by morphing. Movable leading edge flaps are used for this purpose. The equations of the surfaces of the wing, of the fuselage and of the flaps in stretched position are approximated in form of superpositions of homogeneous polynomes in two variables with free coefficients. These coefficients together with the similarity parameters of the planform of the FC are the free parameters of the global optimization. Two enlarged variational problems with free boundaries occur. The first one consists in the determination of the GO shape of the wing-fuselageFC, with the flaps in retracted position, which must be of minimum drag, at higher cruising Mach number. The second enlarged variational problem consists in the determination of the GO shape of the flaps in stretched position in such a manner that the entire FC shall be of minimum drag at the second lower Mach number. The iterative optimum-optimorum (OO theory of the author is used for the solving of these both enlarged variational problems. The inviscid GO shape of the FC is used only in the first step of iteration and the own developed hybrid solutions for the compressible Navier-Stokes partial-differential equations (PDEs are used for the determination of the friction drag coefficient and up the second step of iteration of OO theory.

Moderator Configuration Options for ESS

DEFF Research Database (Denmark)

Zanini, L.; Batkov, K.; Klinkby, Esben Bryndt

2016-01-01

The current, still evolving status of the design and the optimization work for the moderator configuration for the European Spallation Source is described. The moderator design has been strongly driven by the low-dimensional moderator concept recently proposed for use in spallation neutron sources...... or reactors. Quasi-two dimensional, disc- or tube-shaped moderators,can provide strong brightness increase (factor of 3 or more) with respect to volume para-H2moderators, which constitute the reference, state-of-the-art technology for high-intensity coupled moderators. In the design process other, more...... conventional, principles were also considered,such as the importance of moderator positioning, of the premoderator, and beam extraction considerations. Different design and configuration options are evaluated and compared with the reference volume moderator configuration described in the ESS Technical Design...

Examination of energy price policies in Iran for optimal configuration of CHP and CCHP systems based on particle swarm optimization algorithm

International Nuclear Information System (INIS)

Tichi, S.G.; Ardehali, M.M.; Nazari, M.E.

2010-01-01

The current subsidized energy prices in Iran are proposed to be gradually eliminated over the next few years. The objective of this study is to examine the effects of current and future energy price policies on optimal configuration of combined heat and power (CHP) and combined cooling, heating, and power (CCHP) systems in Iran, under the conditions of selling and not-selling electricity to utility. The particle swarm optimization algorithm is used for minimizing the cost function for owning and operating various CHP and CCHP systems in an industrial dairy unit. The results show that with the estimated future unsubsidized utility prices, CHP and CCHP systems operating with reciprocating engine prime mover have total costs of 5.6 and $2.9x10 6 over useful life of 20 years, respectively, while both systems have the same capital recovery periods of 1.3 years. However, for the same prime mover and with current subsidized prices, CHP and CCHP systems require 4.9 and 5.2 years for capital recovery, respectively. It is concluded that the current energy price policies hinder the promotion of installing CHP and CCHP systems and, the policy of selling electricity to utility as well as eliminating subsidies are prerequisites to successful widespread utilization of such systems.

Gas ultrasonic flow rate measurement through genetic-ant colony optimization based on the ultrasonic pulse received signal model

Science.gov (United States)

Hou, Huirang; Zheng, Dandan; Nie, Laixiao

2015-04-01

For gas ultrasonic flowmeters, the signals received by ultrasonic sensors are susceptible to noise interference. If signals are mingled with noise, a large error in flow measurement can be caused by triggering mistakenly using the traditional double-threshold method. To solve this problem, genetic-ant colony optimization (GACO) based on the ultrasonic pulse received signal model is proposed. Furthermore, in consideration of the real-time performance of the flow measurement system, the improvement of processing only the first three cycles of the received signals rather than the whole signal is proposed. Simulation results show that the GACO algorithm has the best estimation accuracy and ant-noise ability compared with the genetic algorithm, ant colony optimization, double-threshold and enveloped zero-crossing. Local convergence doesn’t appear with the GACO algorithm until -10 dB. For the GACO algorithm, the converging accuracy and converging speed and the amount of computation are further improved when using the first three cycles (called GACO-3cycles). Experimental results involving actual received signals show that the accuracy of single-gas ultrasonic flow rate measurement can reach 0.5% with GACO-3 cycles, which is better than with the double-threshold method.

Development of Compact Quasi-Axisymmetric Stellarator Reactor Configurations

International Nuclear Information System (INIS)

Ku, L.P.; Zarnstorff, M.; White, R.B.; Cooper, W.A.; Sanchez, R.; Neilson, H.; Schmidt, J.A.

2003-01-01

We have started to examine the reactor potential of quasi-axisymmetric (QA) stellarators with an integrated approach that includes systems evaluation, engineering considerations, and plasma and coil optimizations. In this paper, we summarize the progress made so far in developing QA configurations with reduced alpha losses while retaining good MHD stability properties. The minimization of alpha losses is achieved by directly targeting the collisionless orbits to prolong the average resident times. Configurations with an overall energy loss rate of ∼10% or less, including collisional contributions, have been found. To allow remotely maintaining coils and machine components in a reactor environment, there is a desire to simplify to the extent possible the coil design. To this end, finding a configuration that is optimized not only for the alpha confinement and MHD stability but also for the good coil and reactor performance, remains to be a challenging task

Optimizing Orbit-Instrument Configuration for Global Precipitation Mission (GPM) Satellite Fleet

Science.gov (United States)

Smith, Eric A.; Adams, James; Baptista, Pedro; Haddad, Ziad; Iguchi, Toshio; Im, Eastwood; Kummerow, Christian; Einaudi, Franco (Technical Monitor)

2001-01-01

Following the scientific success of the Tropical Rainfall Measuring Mission (TRMM) spearheaded by a group of NASA and NASDA scientists, their external scientific collaborators, and additional investigators within the European Union's TRMM Research Program (EUROTRMM), there has been substantial progress towards the development of a new internationally organized, global scale, and satellite-based precipitation measuring mission. The highlights of this newly developing mission are a greatly expanded scope of measuring capability and a more diversified set of science objectives. The mission is called the Global Precipitation Mission (GPM). Notionally, GPM will be a constellation-type mission involving a fleet of nine satellites. In this fleet, one member is referred to as the "core" spacecraft flown in an approximately 70 degree inclined non-sun-synchronous orbit, somewhat similar to TRMM in that it carries both a multi-channel polarized passive microwave radiometer (PMW) and a radar system, but in this case it will be a dual frequency Ku-Ka band radar system enabling explicit measurements of microphysical DSD properties. The remainder of fleet members are eight orbit-synchronized, sun-synchronous "constellation" spacecraft each carrying some type of multi-channel PMW radiometer, enabling no worse than 3-hour diurnal sampling over the entire globe. In this configuration the "core" spacecraft serves as a high quality reference platform for training and calibrating the PMW rain retrieval algorithms used with the "constellation" radiometers. Within NASA, GPM has advanced to the pre-formulation phase which has enabled the initiation of a set of science and technology studies which will help lead to the final mission design some time in the 2003 period. This presentation first provides an overview of the notional GPM program and mission design, including its organizational and programmatic concepts, scientific agenda, expected instrument package, and basic flight

Optimal wireless receiver structure for omnidirectional inductive power transmission to biomedical implants.

Science.gov (United States)

Gougheri, Hesam Sadeghi; Kiani, Mehdi

2016-08-01

In order to achieve omnidirectional inductive power transmission to biomedical implants, the use of several orthogonal coils in the receiver side (Rx) has been proposed in the past. In this paper, the optimal Rx structure for connecting three orthogonal Rx coils and the power management is found to achieve the maximum power delivered to the load (PDL) in the presence of any Rx coil tilting. Unlike previous works, in which a separate power management has been used for each coil to deliver power to the load, different resonant Rx structures for connecting three Rx coils to a single power management are studied. In simulations, connecting three Rx coils with the diameters of 3 mm, 3.3 mm, and 3.6 mm in series and resonating them with a single capacitor at the operation frequency of 100 MHz led to the maximum PDL for large loads when the implant was tilted for 45o. This optimal Rx structure achieves higher PDL in worst-case scenarios as well as reduces the number of power managements to only one.

Measurement Results of the Caltech Submillimeter Observatory 230 GHz and 460 GHz Balanced Receivers

Science.gov (United States)

Kooi, J. W.; Monje, R. R.; Force, B. L.; Rice, F.; Miller, D.; Phillips, T. G.

2010-03-01

The Caltech Submillimeter observatory (CSO) is located on top of Mauna Kea, Hawaii, at an altitude of 4.2km. The existing suite of heterodyne receivers covering the submillimeter band is rapidly aging, and in need of replacement. To this extend we have developed a family of balanced receivers covering the astrophysical important 180-720 GHz atmospheric windows. For the CSO, wide IF bandwidth receivers are implemented in a balanced receiver configuration with dual frequency observation capability. This arrangement was opted to be an optimal compromise between scientific merit and finite funding. In principle, the balanced receiver configuration has the advantage that common mode amplitude noise in the LO system is canceled, while at the same time utilizing all available LO power. Both of these features facilitate the use of commercially available synthesized LO system. In combination with a 4 GHz IF bandwidth, the described receiver layout allows for rapid high resolution spectral line surveys. Dual frequency observation is another important mode of operation offered by the new facility instrumentation. Two band observations are accomplished by separating the H and V polarizations of the incoming signal and routing them via folded optics to the appropriate polarization sensitive balanced mixer. Scientifically this observation mode facilitates pointing for the higher receiver band under mediocre weather conditions and a doubling of scientific throughput (2 x 4 GHz) under good weather conditions. Not only do these changes greatly enhance the spectroscopic capabilities of the CSO, they also enable the observatory to be integrated into the Harvard-Smithsonian Submillimeter Array (eSMA) as an additional baseline. The upgrade of the 345 GHz/650 GHz dual band balanced receivers is not far behind. All the needed hardware has been procured, and commissioning is expected the summer of 2010. The SIS junctions are capable of a 2-12 GHz bandwidth.

Optimal design of advanced distillation configuration for enhanced energy efficiency of waste solvent recovery process in semiconductor industry

International Nuclear Information System (INIS)

Chaniago, Yus Donald; Minh, Le Quang; Khan, Mohd Shariq; Koo, Kee-Kahb; Bahadori, Alireza; Lee, Moonyong

2015-01-01

Highlights: • Thermally coupled distillation process is proposed for waste solvent recovery. • A systematic optimization procedure is used to optimize distillation columns. • Response surface methodology is applied to optimal design of distillation column. • Proposed advanced distillation allows energy efficient waste solvent recovery. - Abstract: The semiconductor industry is one of the largest industries in the world. On the other hand, the huge amount of solvent used in the industry results in high production cost and potential environmental damage because most of the valuable chemicals discharged from the process are incinerated at high temperatures. A distillation process is used to recover waste solvent, reduce the production-related costs and protect the environment from the semiconductor industrial waste. Therefore, in this study, a distillation process was used to recover the valuable chemicals from semiconductor industry discharge, which otherwise would have been lost to the environment. The conventional sequence of distillation columns, which was optimized using the Box and sequential quadratic programming method for minimum energy objectives, was used. The energy demands of a distillation problem may have a substantial influence on the profitability of a process. A thermally coupled distillation and heat pump-assisted distillation sequence was implemented to further improve the distillation performance. Finally, a comparison was made between the conventional and advanced distillation sequences, and the optimal conditions for enhancing recovery were determined. The proposed advanced distillation configuration achieved a significant energy saving of 40.5% compared to the conventional column sequence

Gas ultrasonic flow rate measurement through genetic-ant colony optimization based on the ultrasonic pulse received signal model

International Nuclear Information System (INIS)

Hou, Huirang; Zheng, Dandan; Nie, Laixiao

2015-01-01

For gas ultrasonic flowmeters, the signals received by ultrasonic sensors are susceptible to noise interference. If signals are mingled with noise, a large error in flow measurement can be caused by triggering mistakenly using the traditional double-threshold method. To solve this problem, genetic-ant colony optimization (GACO) based on the ultrasonic pulse received signal model is proposed. Furthermore, in consideration of the real-time performance of the flow measurement system, the improvement of processing only the first three cycles of the received signals rather than the whole signal is proposed. Simulation results show that the GACO algorithm has the best estimation accuracy and ant-noise ability compared with the genetic algorithm, ant colony optimization, double-threshold and enveloped zero-crossing. Local convergence doesn’t appear with the GACO algorithm until –10 dB. For the GACO algorithm, the converging accuracy and converging speed and the amount of computation are further improved when using the first three cycles (called GACO-3cycles). Experimental results involving actual received signals show that the accuracy of single-gas ultrasonic flow rate measurement can reach 0.5% with GACO-3 cycles, which is better than with the double-threshold method. (paper)

Open space preservation, property value, and optimal spatial configuration

Science.gov (United States)

Yong Jiang; Stephen K. Swallow

2007-01-01

The public has increasingly demonstrated a strong support for open space preservation. How to finance the socially efficient level of open space with the optimal spatial structure is of high policy relevance to local governments. In this study, we developed a spatially explicit open space model to help identify the socially optimal amount and optimal spatial...

Numerical study of the connection lengths for various magnetic configurations in Wendelstein 7-X to optimize the heat load on the divertor

Energy Technology Data Exchange (ETDEWEB)

Sinha, Priyanjana; Hoelbe, Hauke; Sunn Pedersen, Thomas [Max Planck Institute of Plasma Physics, Greifswald (Germany)

2016-07-01

Fusion has the potential to play an important role as a future energy resource. It has the capacity to produce large-scale clean energy. The two main confinement concepts are the tokamak and the stellarator. The W7-X machine is based on stellarator principle and is using special form of coils to achieve steady-state plasma confinement. Divertors are used in tokamaks and stellarator to control the exhaust of waste gases and impurities from the machine. The divertor concept of W7-X is a so-called island divertor. The island chain isolates the confinement core from regions where the plasma-wall interaction takes place. The area of the divertor that receives the main part of the heat loads, the so-called wetted area, increases with the distance along the magnetic field from the outboard midplane to the divertor target. The connection length is relatively short in tokamaks with conventional divertors. In the stellarator island divertor, the connection length can be varied significantly, which should allow for optimization of the wetted area. We present here a numerical study of the achievable connection lengths in various W7-X configurations and discuss the possibilities for running dedicated experiments to understand the physics of what sets the wetted area.

Sex and Electrode Configuration in Transcranial Electrical Stimulation

Directory of Open Access Journals (Sweden)

Michael J. Russell

2017-08-01

Full Text Available Transcranial electrical stimulation (tES can be an effective non-invasive neuromodulation procedure. Unfortunately, the considerable variation in reported treatment outcomes, both within and between studies, has made the procedure unreliable for many applications. To determine if individual differences in cranium morphology and tissue conductivity can account for some of this variation, the electrical density at two cortical locations (temporal and frontal directly under scalp electrodes was modeled using a validated MRI modeling procedure in 23 subjects (12 males and 11 females. Three different electrode configurations (non-cephalic, bi-cranial, and ring commonly used in tES were modeled at three current intensities (0.5, 1.0, and 2.0 mA. The aims were to assess the effects of configuration and current intensity on relative current received at a cortical brain target directly under the stimulating electrode and to characterize individual variation. The different electrode configurations resulted in up to a ninefold difference in mean current densities delivered to the brains. The ring configuration delivered the least current and the non-cephalic the most. Female subjects showed much less current to the brain than male subjects. Individual differences in the current received and differences in electrode configurations may account for significant variability in current delivered and, thus, potentially a significant portion of reported variation in clinical outcomes at two commonly targeted regions of the brain.

Particle exhaust scheme using an in-vessel cryocondensation pump in the advanced divertor configuration of the DIII-D tokamak

International Nuclear Information System (INIS)

Menon, M.M.; Mioduszewski, P.K.; Owen, L.W.; Anderson, P.M.; Baxi, C.B.; Langhorn, A.; Luxon, J.L.; Mahdavi, M.A.; Schaffer, M.J.; Schaubel, K.M.; "" class="author-name" title=" (General Atomics Co., San Diego, CA (United States))" data-affiliation=" (General Atomics Co., San Diego, CA (United States))" >Smith, J.P>

1992-01-01

In this paper, a particle exhaust scheme using a cryocondensation pump in the advanced divertor configuration of the DIII-D tokamak is described. In this configuration, the pump is located inside a baffle chamber within the tokamak, designed to receive particles reflected off the divertor strike region. A concentric coaxial loop with forced-convection flow of two-phase helium is selected as the cryocondensation surface. The pumping configuration is optimized by Monte Carlo techniques to provide maximum exhaust efficiency while minimizing the deleterious effects of impingement of energetic plasma particles on cryogenic surfaces. Heat loading contributions from various sources on the cryogenic surfaces are estimated, based on which the cryogenic surfaces are estimated, based on which the cryogenic flow loop for the pump is designed. The mechanical aspects of the pump, designed to meet the many challenging requirements of operating the cryopump internal to the tokamak vacuum and in close proximity with the high-temperature plasma, are also outlined

Optimal power allocation of a single transmitter-multiple receivers channel in a cognitive sensor network

KAUST Repository

Ayala Solares, Jose Roberto

2012-08-01

The optimal transmit power of a wireless sensor network with one transmitter and multiple receivers in a cognitive radio environment while satisfying independent peak, independent average, sum of peak and sum of average transmission rate constraints is derived. A suboptimal scheme is proposed to overcome the frequency of outages for the independent peak transmission rate constraint. In all cases, numerical results are provided for Rayleigh fading channels. © 2012 IEEE.

Customizable Digital Receivers for Radar

Science.gov (United States)

Moller, Delwyn; Heavey, Brandon; Sadowy, Gregory

2008-01-01

Compact, highly customizable digital receivers are being developed for the system described in 'Radar Interferometer for Topographic Mapping of Glaciers and Ice Sheets' (NPO-43962), NASA Tech Briefs, Vol. 31, No. 7 (August 2007), page 72. The receivers are required to operate in unison, sampling radar returns received by the antenna elements in a digital beam-forming (DBF) mode. The design of these receivers could also be adapted to commercial radar systems. At the time of reporting the information for this article, there were no commercially available digital receivers capable of satisfying all of the operational requirements and compact enough to be mounted directly on the antenna elements. A provided figure depicts the overall system of which the digital receivers are parts. Each digital receiver includes an analog-to-digital converter (ADC), a demultiplexer (DMUX), and a field-programmable gate array (FPGA). The ADC effects 10-bit band-pass sampling of input signals having frequencies up to 3.5 GHz. The input samples are demultiplexed at a user-selectable rate of 1:2 or 1:4, then buffered in part of the FPGA that functions as a first-in/first-out (FIFO) memory. Another part of the FPGA serves as a controller for the ADC, DMUX, and FIFO memory and as an interface between (1) the rest of the receiver and (2) a front-panel data port (FPDP) bus, which is an industry-standard parallel data bus that has a high data-rate capability and multichannel configuration suitable for DBF. Still other parts of the FPGA in each receiver perform signal-processing functions. The digital receivers can be configured to operate in a stand-alone mode, or in a multichannel mode as needed for DBF. The customizability of the receiver makes it applicable to a broad range of system architectures. The capability for operation of receivers in either a stand-alone or a DBF mode enables the use of the receivers in an unprecedentedly wide variety of radar systems.

Microsurgical Bypass Training Rat Model: Part 2-Anastomosis Configurations.

Science.gov (United States)

Tayebi Meybodi, Ali; Lawton, Michael T; Yousef, Sonia; Mokhtari, Pooneh; Gandhi, Sirin; Benet, Arnau

2017-11-01

Mastery of microsurgical anastomosis is key to achieving good outcomes in cerebrovascular bypass procedures. Animal models (especially rodents) provide an optimal preclinical bypass training platform. However, the existing models for practicing different anastomosis configurations have several limitations. We sought to optimize the use of the rat's abdominal aorta and common iliac arteries (CIA) for practicing the 3 main anastomosis configurations commonly used in cerebrovascular surgery. Thirteen male Sprague-Dawley rats underwent inhalant anesthesia. The abdominal aorta and the CIAs were exposed. The distances between the major branches of the aorta were measured to find the optimal location for an end-to-end anastomosis. Also, the feasibility of performing side-to-side and end-to-side anastomoses between the CIAs was assessed. All bypass configurations could be performed between the left renal artery and the CIA bifurcation. The longest segments of the aorta without major branches were 1) between the left renal and left iliolumbar arteries (16.9 mm ± 4.6), and 2) between the right iliolumbar artery and the aortic bifurcation (9.7 mm ± 4.7). The CIAs could be juxtaposed for an average length of 7.6 mm ± 1.3, for a side-to-side anastomosis. The left CIA could be successfully reimplanted on to the right CIA at an average distance of 9.1 mm ± 1.6 from the aortic bifurcation. Our results show that rat's abdominal aorta and CIAs may be effectively used for all the anastomosis configurations used in cerebral revascularization procedures. We also provide technical nuances and anatomic descriptions to plan for practicing each bypass configuration. Copyright © 2017 Elsevier Inc. All rights reserved.

Dynamic airspace configuration by genetic algorithm

Directory of Open Access Journals (Sweden)

Marina Sergeeva

2017-06-01

Full Text Available With the continuous air traffic growth and limits of resources, there is a need for reducing the congestion of the airspace systems. Nowadays, several projects are launched, aimed at modernizing the global air transportation system and air traffic management. In recent years, special interest has been paid to the solution of the dynamic airspace configuration problem. Airspace sector configurations need to be dynamically adjusted to provide maximum efficiency and flexibility in response to changing weather and traffic conditions. The main objective of this work is to automatically adapt the airspace configurations according to the evolution of traffic. In order to reach this objective, the airspace is considered to be divided into predefined 3D airspace blocks which have to be grouped or ungrouped depending on the traffic situation. The airspace structure is represented as a graph and each airspace configuration is created using a graph partitioning technique. We optimize airspace configurations using a genetic algorithm. The developed algorithm generates a sequence of sector configurations for one day of operation with the minimized controller workload. The overall methodology is implemented and successfully tested with air traffic data taken for one day and for several different airspace control areas of Europe.

Thermal Performance Evaluation of the 200 kWth Sol Air Volumetric Solar Receiver

International Nuclear Information System (INIS)

Tellez Sufrategui, F. M.

2003-01-01

The goal of the Solair project is the design and test of a fully modular, high efficient and durable open volumetric high-flux receiver, which can be easily and safely operated at mean air outlet temperatures of up to 800 degree centigree. The project was thought in two phases, in the first one an advanced 200 kW HitRec receiver called Solair 200 was designed and tested. The Solair 200 was built like one single receiver module (subassembly), to test the thermal performance of the receiver as well as the receiver module behavior. Out of a set of these receiver modules have been developed to assemble the 3 MW t h receiver in the second phase of the project. This report describes the used procedure or methodology for data processing for thermal performance evaluation purposes and the data processing results for the first phase of the project. Test campaign started in March 2002 and produced fifty data sheets (each corresponding to a test day) and ended in February 2003. During the test phase three absorber material types (or configurations) have been tested during the test campaign. The data processing and evaluation results show that performance goals for the receiver have been fluffy accomplished: Temperatures of more than 800 degree centigree were achieved for the first two configurations in five test days. For the two absorber configurations for which incident solar power was measured the estimated efficiency at 700 degree centigree was 81 (±6)% for configuration 1 and 83 (±6) % for configuration 2 of the absorber. (Author) 20 refs

Thermal Performance Evaluation of the 200kWth SolAir Volumetric Solar Receiver

Energy Technology Data Exchange (ETDEWEB)

Tellez Sufrategui, F. M.

2003-07-01

The goal of the Solair project the design and test of a fully modular, high efficient and durable open volumetric high-flux receiver, which can be easily and safety operated at mean air outlet temperatures of up to 800 degree centigree. The project was thought in two phases, in the first one an advanced 200 kW Hitrec receiver called Solair 200 was designed and tested. The Solair 200 was built like one single receiver module (subassembly), to test the thermal performance of the receiver as well as the receiver module behavior. Out of a set of these receiver modules have been developed to assemble the 3 MWth receiver in the second phase of the project. This report describes the used procedure or methodology for data processing for thermal performance evaluation purposes and the data processing results for the first phase of the project. Test campaign started in March 2002 and produced fifty data sheets (each corresponding to a test day) and ended in February 2003. During the test phase three absorber material types (or configurations) have been tested during the test campaign. The data processing and evaluation results show that performance goals for the receiver have been fully accomplished. Temperatures of more than 800 degree centigree were achieved for the first two configurations in five test days. For the two absorber configurations for which incident solar power was measured the estimated efficiency at 700 degree centigree was 81 ({+-}6)% for configuration 1 and 83({+-}6)% for configuration 2 of the absorber. (Author). 20 refs.

Hybrid Microgrid Configuration Optimization with Evolutionary Algorithms

Science.gov (United States)

Lopez, Nicolas

This dissertation explores the Renewable Energy Integration Problem, and proposes a Genetic Algorithm embedded with a Monte Carlo simulation to solve large instances of the problem that are impractical to solve via full enumeration. The Renewable Energy Integration Problem is defined as finding the optimum set of components to supply the electric demand to a hybrid microgrid. The components considered are solar panels, wind turbines, diesel generators, electric batteries, connections to the power grid and converters, which can be inverters and/or rectifiers. The methodology developed is explained as well as the combinatorial formulation. In addition, 2 case studies of a single objective optimization version of the problem are presented, in order to minimize cost and to minimize global warming potential (GWP) followed by a multi-objective implementation of the offered methodology, by utilizing a non-sorting Genetic Algorithm embedded with a monte Carlo Simulation. The method is validated by solving a small instance of the problem with known solution via a full enumeration algorithm developed by NREL in their software HOMER. The dissertation concludes that the evolutionary algorithms embedded with Monte Carlo simulation namely modified Genetic Algorithms are an efficient form of solving the problem, by finding approximate solutions in the case of single objective optimization, and by approximating the true Pareto front in the case of multiple objective optimization of the Renewable Energy Integration Problem.

Optimal Sunshade Configurations for Space-Based Geoengineering near the Sun-Earth L1 Point.

Directory of Open Access Journals (Sweden)

Joan-Pau Sánchez

Full Text Available Within the context of anthropogenic climate change, but also considering the Earth's natural climate variability, this paper explores the speculative possibility of large-scale active control of the Earth's radiative forcing. In particular, the paper revisits the concept of deploying a large sunshade or occulting disk at a static position near the Sun-Earth L1 Lagrange equilibrium point. Among the solar radiation management methods that have been proposed thus far, space-based concepts are generally seen as the least timely, albeit also as one of the most efficient. Large occulting structures could potentially offset all of the global mean temperature increase due to greenhouse gas emissions. This paper investigates optimal configurations of orbiting occulting disks that not only offset a global temperature increase, but also mitigate regional differences such as latitudinal and seasonal difference of monthly mean temperature. A globally resolved energy balance model is used to provide insights into the coupling between the motion of the occulting disks and the Earth's climate. This allows us to revise previous studies, but also, for the first time, to search for families of orbits that improve the efficiency of occulting disks at offsetting climate change on both global and regional scales. Although natural orbits exist near the L1 equilibrium point, their period does not match that required for geoengineering purposes, thus forced orbits were designed that require small changes to the disk attitude in order to control its motion. Finally, configurations of two occulting disks are presented which provide the same shading area as previously published studies, but achieve reductions of residual latitudinal and seasonal temperature changes.

Optimal Sunshade Configurations for Space-Based Geoengineering near the Sun-Earth L1 Point.

Science.gov (United States)

Sánchez, Joan-Pau; McInnes, Colin R

2015-01-01

Within the context of anthropogenic climate change, but also considering the Earth's natural climate variability, this paper explores the speculative possibility of large-scale active control of the Earth's radiative forcing. In particular, the paper revisits the concept of deploying a large sunshade or occulting disk at a static position near the Sun-Earth L1 Lagrange equilibrium point. Among the solar radiation management methods that have been proposed thus far, space-based concepts are generally seen as the least timely, albeit also as one of the most efficient. Large occulting structures could potentially offset all of the global mean temperature increase due to greenhouse gas emissions. This paper investigates optimal configurations of orbiting occulting disks that not only offset a global temperature increase, but also mitigate regional differences such as latitudinal and seasonal difference of monthly mean temperature. A globally resolved energy balance model is used to provide insights into the coupling between the motion of the occulting disks and the Earth's climate. This allows us to revise previous studies, but also, for the first time, to search for families of orbits that improve the efficiency of occulting disks at offsetting climate change on both global and regional scales. Although natural orbits exist near the L1 equilibrium point, their period does not match that required for geoengineering purposes, thus forced orbits were designed that require small changes to the disk attitude in order to control its motion. Finally, configurations of two occulting disks are presented which provide the same shading area as previously published studies, but achieve reductions of residual latitudinal and seasonal temperature changes.

Importance measures in risk-informed decision making: Ranking, optimisation and configuration control

Energy Technology Data Exchange (ETDEWEB)

Vaurio, Jussi K., E-mail: jussi.vaurio@pp1.inet.fi [Prometh Solutions, Hiihtaejaenkuja 3K, 06100 Porvoo (Finland)

2011-11-15

This paper describes roles, extensions and applications of importance measures of components and configurations for making risk-informed decisions relevant to system operations, maintenance and safety. Basic importance measures and their relationships are described for independent and mutually exclusive events and for groups of events associated with common cause failures. The roles of importances are described mainly in two groups of activities: (a) ranking safety significance of systems, structures, components and human actions for preventive safety assurance activities, and (b) making decisions about permissible permanent and temporary configurations and allowed configuration times for regulation, technical specifications and for on-line risk monitoring. Criticality importance and sums of criticalities turn out to be appropriate measures for ranking and optimization. Several advantages are pointed out and consistent ranking of pipe segments for in-service inspection is provided as an example. Risk increase factor and its generalization risk gain are most appropriately used to assess corrective priorities and acceptability of a situation when components are already failed or when planning to take one or more components out of service for maintenance. Precise definitions are introduced for multi-failure configurations and it is shown how they can be assessed under uncertainties, in particular when common cause failures or success states may be involved. A general weighted average method is compared to other candidate methods in benchmark cases. It is the preferable method for prediction when a momentary configuration is known or only partially known. Potential applications and optimization of allowed outage times are described. The results show how to generalize and apply various importance measures to ranking and optimization and how to manage configurations in uncertain multi-failure situations. - Highlights: > Rigorous methods developed for using importances

Importance measures in risk-informed decision making: Ranking, optimisation and configuration control

International Nuclear Information System (INIS)

Vaurio, Jussi K.

2011-01-01

This paper describes roles, extensions and applications of importance measures of components and configurations for making risk-informed decisions relevant to system operations, maintenance and safety. Basic importance measures and their relationships are described for independent and mutually exclusive events and for groups of events associated with common cause failures. The roles of importances are described mainly in two groups of activities: (a) ranking safety significance of systems, structures, components and human actions for preventive safety assurance activities, and (b) making decisions about permissible permanent and temporary configurations and allowed configuration times for regulation, technical specifications and for on-line risk monitoring. Criticality importance and sums of criticalities turn out to be appropriate measures for ranking and optimization. Several advantages are pointed out and consistent ranking of pipe segments for in-service inspection is provided as an example. Risk increase factor and its generalization risk gain are most appropriately used to assess corrective priorities and acceptability of a situation when components are already failed or when planning to take one or more components out of service for maintenance. Precise definitions are introduced for multi-failure configurations and it is shown how they can be assessed under uncertainties, in particular when common cause failures or success states may be involved. A general weighted average method is compared to other candidate methods in benchmark cases. It is the preferable method for prediction when a momentary configuration is known or only partially known. Potential applications and optimization of allowed outage times are described. The results show how to generalize and apply various importance measures to ranking and optimization and how to manage configurations in uncertain multi-failure situations. - Highlights: → Rigorous methods developed for using importances

Low emittance configuration for spear

International Nuclear Information System (INIS)

Blumberg, L.N.; Harris, J.; Stege, R.; Cerino, J.; Hettel, R.; Hofmann, A.; Liu, R.Z.; Wiedemann, H.; Winick, H.

1985-01-01

The quality of synchrotron radiation beams from SPEAR, in particular the brilliance of undulator radiation, can be improved significantly by reducing the emittance of the stored electron beam. A reduction of the horizontal emittance by a factor of 3.5 to a value of 130 nanometer-radians (nm-r) at 3 GeV has been achieved by using stronger focussing, mainly in the horizontal plane. The low emittance configuration also reduces the dispersion and vertical beta functions in the straight sections, making them more suitable for wigglers. The higher betatron tunes lead to a larger phase advance between the two kickers, which has to be corrected during injection by shunting current from some quadrupoles. The configuration was optimized within SPEAR hardware limitations and tested for dynamic aperture with the tracking program PATRICIA. After implementation of this scheme, beam was successfully injected and accumulated. The measured emittance of the stored beam was in agreement with calculations. Presently the configuration is being made operational

Dependence of cycle optimal configuration for closed gas turbines on thermodynamic properties of working fluids

International Nuclear Information System (INIS)

Andryushchenko, A.I.; Dubinin, A.B.; Krylov, E.E.

1988-01-01

The problem of choice of working fluids for NPP closed gas turbines (CGT) is discussed. Thermostable in the working temperature range, chemically inert relatively to structural materials, fire- and explosion - proof substances, radiation-resistant and having satisfactory neutron-physical characteristics are used as the working fluids. Final choice of a gas as a working fluid is exercised based on technical and economic comparison of different variants at optimum thermodynamic cycle and parameters for each gas. The character and degree of the effect of thermodynamic properties of gases on configuration of reference cycles of regenerative CGT are determined. It is established that efficiency and optimum parameters in nodal points of the reference cycle are specified by the degree of removing the compression processes from the critical point. Practical importance of the obtained results presupposes the possibility of rapid estimation of the efficiency of using a gas without multiparametric optimization

Improvement in pulmonary functions and clinical parameters due to addition of breathing exercises in asthma patients receiving optimal treatment

Directory of Open Access Journals (Sweden)

Dipti Agarwal

2017-01-01

Conclusions: Breathing exercises provided significant improvements in spirometric parameters and significant reduction in breathlessness, wheezing, and nocturnal symptoms as well as requirements of rescue medicines in asthma patients who were receiving optimal asthma treatment.

Heuristic Approach for Configuration of a Grid-Tied Microgrid in Puerto Rico

Science.gov (United States)

Rodriguez, Miguel A.

The high rates of cost of electricity that consumers are being charged by the utility grid in Puerto Rico have created an energy crisis around the island. This situation is due to the island's dependence on imported fossil fuels. In order to aid in the transition from fossil-fuel based electricity into electricity from renewable and alternative sources, this research work focuses on reducing the cost of electricity for Puerto Rico through means of finding the optimal microgrid configuration for a set number of consumers from the residential sector. The Hybrid Optimization Modeling for Energy Renewables (HOMER) software, developed by NREL, is utilized as an aid in determining the optimal microgrid setting. The problem is also approached via convex optimization; specifically, an objective function C(t) is formulated in order to be minimized. The cost function depends on the energy supplied by the grid, the energy supplied by renewable sources, the energy not supplied due to outages, as well as any excess energy sold to the utility in a yearly manner. A term for considering the social cost of carbon is also considered in the cost function. Once the microgrid settings from HOMER are obtained, those are evaluated via the optimized function C( t), which will in turn assess the true optimality of the microgrid configuration. A microgrid to supply 10 consumers is considered; each consumer can possess a different microgrid configuration. The cost function C( t) is minimized, and the Net Present Value and Cost of Electricity are computed for each configuration, in order to assess the true feasibility. Results show that the greater the penetration of components into the microgrid, the greater the energy produced by the renewable sources in the microgrid, the greater the energy not supplied due to outages. The proposed method demonstrates that adding large amounts of renewable components in a microgrid does not necessarily translates into economic benefits for the consumer; in

Optimizing Sparse Matrix-Multiple Vectors Multiplication for Nuclear Configuration Interaction Calculations

Energy Technology Data Exchange (ETDEWEB)

Aktulga, Hasan Metin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Buluc, Aydin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Williams, Samuel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yang, Chao [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2014-08-14

Obtaining highly accurate predictions on the properties of light atomic nuclei using the configuration interaction (CI) approach requires computing a few extremal Eigen pairs of the many-body nuclear Hamiltonian matrix. In the Many-body Fermion Dynamics for nuclei (MFDn) code, a block Eigen solver is used for this purpose. Due to the large size of the sparse matrices involved, a significant fraction of the time spent on the Eigen value computations is associated with the multiplication of a sparse matrix (and the transpose of that matrix) with multiple vectors (SpMM and SpMM-T). Existing implementations of SpMM and SpMM-T significantly underperform expectations. Thus, in this paper, we present and analyze optimized implementations of SpMM and SpMM-T. We base our implementation on the compressed sparse blocks (CSB) matrix format and target systems with multi-core architectures. We develop a performance model that allows us to understand and estimate the performance characteristics of our SpMM kernel implementations, and demonstrate the efficiency of our implementation on a series of real-world matrices extracted from MFDn. In particular, we obtain 3-4 speedup on the requisite operations over good implementations based on the commonly used compressed sparse row (CSR) matrix format. The improvements in the SpMM kernel suggest we may attain roughly a 40% speed up in the overall execution time of the block Eigen solver used in MFDn.

Sensor Networks for Optimal Target Localization with Bearings-Only Measurements in Constrained Three-Dimensional Scenarios

Directory of Open Access Journals (Sweden)

Joaquin Aranda

2013-08-01

Full Text Available In this paper, we address the problem of determining the optimal geometric configuration of an acoustic sensor network that will maximize the angle-related information available for underwater target positioning. In the set-up adopted, a set of autonomous vehicles carries a network of acoustic units that measure the elevation and azimuth angles between a target and each of the receivers on board the vehicles. It is assumed that the angle measurements are corrupted by white Gaussian noise, the variance of which is distance-dependent. Using tools from estimation theory, the problem is converted into that of minimizing, by proper choice of the sensor positions, the trace of the inverse of the Fisher Information Matrix (also called the Cramer-Rao Bound matrix to determine the sensor configuration that yields the minimum possible covariance of any unbiased target estimator. It is shown that the optimal configuration of the sensors depends explicitly on the intensity of the measurement noise, the constraints imposed on the sensor configuration, the target depth and the probabilistic distribution that defines the prior uncertainty in the target position. Simulation examples illustrate the key results derived.

Sensor networks for optimal target localization with bearings-only measurements in constrained three-dimensional scenarios.

Science.gov (United States)

Moreno-Salinas, David; Pascoal, Antonio; Aranda, Joaquin

2013-08-12

In this paper, we address the problem of determining the optimal geometric configuration of an acoustic sensor network that will maximize the angle-related information available for underwater target positioning. In the set-up adopted, a set of autonomous vehicles carries a network of acoustic units that measure the elevation and azimuth angles between a target and each of the receivers on board the vehicles. It is assumed that the angle measurements are corrupted by white Gaussian noise, the variance of which is distance-dependent. Using tools from estimation theory, the problem is converted into that of minimizing, by proper choice of the sensor positions, the trace of the inverse of the Fisher Information Matrix (also called the Cramer-Rao Bound matrix) to determine the sensor configuration that yields the minimum possible covariance of any unbiased target estimator. It is shown that the optimal configuration of the sensors depends explicitly on the intensity of the measurement noise, the constraints imposed on the sensor configuration, the target depth and the probabilistic distribution that defines the prior uncertainty in the target position. Simulation examples illustrate the key results derived.

Receiver-exciter controller design

Science.gov (United States)

Jansma, P. A.

1982-01-01

A description of the general design of both the block 3 and block 4 receiver-exciter controllers for the Deep Space Network (DSN) Mark IV-A System is presented along with the design approach. The controllers are designed to enable the receiver-exciter subsystem (RCV) to be configured, calibrated, initialized and operated from a central location via high level instructions. The RECs are designed to be operated under the control of the DMC subsystem. The instructions are in the form of standard subsystem blocks (SSBs) received via the local area network (LAN). The centralized control provided by RECs and other DSCC controllers in Mark IV-A is intended to reduce DSN operations costs from the Mark III era.

Monte Carlo simulations as a part of the configuration for neutron instruments

International Nuclear Information System (INIS)

Andersen, P.; Lefmann, K.; Theil Kuhn, L.; Willendrup, P.K.; Farhi, E.

2004-01-01

We demonstrate the use of simulations in the process of determining the optimal instrument setup by virtual experiments using the simulation package McStas. The focus of the analysis is the optimization of the multi-blade analyzer present at the RITA-II spectrometer at PSI for a test experiment with powder diffraction. The agreement in resolution and signal-to-background ratio between measurements and simulations shows the validity of the approach. For a sample with broadened Bragg peaks, the optimal instrument configuration could be established only on careful consideration. This shows that in general instrument simulations are approaching a state where they can assist users in selecting the optimal configuration and possibly demonstrate the feasibility of their experiments prior to allocated beamtime

Second-Order Optimal Array Receivers for Synchronization of BPSK, MSK, and GMSK Signals Corrupted by Noncircular Interferences

Directory of Open Access Journals (Sweden)

Chevalier Pascal

2007-01-01

Full Text Available The synchronization and/or time acquisition problem in the presence of interferences has been strongly studied these last two decades, mainly to mitigate the multiple access interferences from other users in DS/CDMA systems. Among the available receivers, only some scarce receivers may also be used in other contexts such as F/TDMA systems. However, these receivers assume implicitly or explicitly circular (or proper interferences and become suboptimal for noncircular (or improper interferences. Such interferences are characteristic in particular of radio communication networks using either rectilinear (or monodimensional modulations such as BPSK modulation or modulation becoming quasirectilinear after a preprocessing such as MSK, GMSK, or OQAM modulations. For this reason, the purpose of this paper is to introduce and to analyze the performance of second-optimal array receivers for synchronization and/or time acquisition of BPSK, MSK, and GMSK signals corrupted by noncircular interferences. For given performances and in the presence of rectilinear signal and interferences, the proposed receiver allows a reduction of the number of sensors by a factor at least equal to two.

Multilayer Substrate Configuration Enhances Removal Efficiency of Pollutants in Constructed Wetlands

Directory of Open Access Journals (Sweden)

Shaoyuan Bai

2016-11-01

Full Text Available This study aimed at optimizing horizontal subsurface flow constructed wetlands (CWs to improve hydraulic performance and pollutant removal efficiency. A groundwater modeling package (MODFLOW was used to optimize three design parameters (length-to-width ratio, inlet/outlet-to-length ratio, and substrate size configuration. Using the optimized parameters, three pilot-scale CWs were built to treat actual wastewater. For model validation, we used a tracer test to evaluate hydraulic performance, and investigated the pollutant spatial distributions and removal efficiencies. We conclude that MODFLOW is suitable for designing CWs, accurately predicting that increasing hydraulic conductivity from surface to bottom layers could improve performance. However, the effect of vegetation, which decreased the hydraulic conductivity of the surface layer, should be considered to improve simulation results. Multilayer substrate configuration, with increasing hydraulic conductivity from the surface to bottom layers, significantly increased pollutant removal compared with monolayer configuration. The spatial variation in pollutant transport and degradation through the filling substrate showed that the multilayer configuration was able to increase use of the available space and moderately reduced short-circuiting and dead zones. Thus, multilayer CWs had higher experimental retention times, effective volume fractions and hydraulic efficiencies, and lower short-circuiting compared with monolayer CWs operating under similar conditions.

Optimization of Gas Turbine Cogeneration Systemfor Various Heat Exchanger Configurations Optimisation des systèmes de turbine à combustion en cogénération pour différentes configurations des échangeurs de chaleur

Directory of Open Access Journals (Sweden)

Costea M.

2011-11-01

Full Text Available The present paper investigates and compares the performance of three configurations of Gas Turbine systems allowing cogeneration of heat and electricity, on the basis of an irreversible regenerative Brayton-Joule cycle. The proposed model is developed for two different cycle constraints, namely, an imposed heat transfer rate released by the fuel combustion, or an imposed maximum cycle temperature. The model also includes the irreversibility due to the friction in the compressor and turbine, and due to the heat losses in the combustion chamber and heat exchangers. Energy efficiency for the system without and with cogeneration, and the exergetic efficiency are used in order to emphasize the cogeneration advantages, but also to help the designer to choose the best configuration of the Gas Turbine system that suits to his needs. Experimental data from a real operating microturbine were used to validate the model. The power output and the energy and exergetic efficiencies are optimized with respect to a set of operating parameters. The optimum values of the Gas Turbine engine parameters corresponding to maximum power output and respectively to maximum thermodynamic efficiency are discussed. The results show same optimal values of the compression ratio corresponding to almost all maximum performances for an imposed heat transfer rate released by the fuel combustion, excepting the maximum exergetic efficiency that requires higher optimal values of the compression ratio than the maximum exergy rate one. A performance comparison of the three configurations is done and future perspectives of the work are proposed. Cet article explore et compare les performances des trois configurations de systèmes de turbine à combustion permettant la production combinée de chaleur et d’électricité, sur la base du cycle irréversible régénératif de Brayton-Joule. Le modèle proposé est développé pour deux contraintes différentes sur le cycle, notamment le

Reliability Equivalence to Symmetrical UHVDC Transmission Systems Considering Redundant Structure Configuration

Directory of Open Access Journals (Sweden)

Xing Jiang

2018-03-01

Full Text Available In recent years, the ultra-high voltage direct current (UHVDC transmission system has been developed rapidly for its significant long-distance, high-capacity and low-loss properties. Equipment failures and overall outages of the UHVDC system have increasingly vital influence on the power supply of the receiving end grid. To improve the reliability level of UHVDC systems, a quantitative selection and configuration approach of redundant structures is proposed in this paper, which is based on multi-state reliability equivalence. Specifically, considering the symmetry characteristic of an UHVDC system, a state space model is established as a monopole rather than a bipole, which effectively reduces the state space dimensions to be considered by deducing the reliability merging operator of two poles. Considering the standby effect of AC filters and the recovery effect of converter units, the number of available converter units and corresponding probability are expressed with in universal generating function (UGF form. Then, a sensitivity analysis is performed to quantify the impact of component reliability parameters on system reliability and determine the most specific devices that should be configured in the redundant structure. Finally, a cost-benefit analysis is utilized to help determine the optimal scheme of redundant devices. Case studies are conducted to demonstrate the effectiveness and accuracy of the proposed method. Based on the numerical results, configuring a set of redundant transformers is indicated to be of the greatest significance to improve the reliability level of UHVDC transmission systems.

Optimal and Suboptimal Finger Selection Algorithms for MMSE Rake Receivers in Impulse Radio Ultra-Wideband Systems

Directory of Open Access Journals (Sweden)

Chiang Mung

2006-01-01

Full Text Available The problem of choosing the optimal multipath components to be employed at a minimum mean square error (MMSE selective Rake receiver is considered for an impulse radio ultra-wideband system. First, the optimal finger selection problem is formulated as an integer programming problem with a nonconvex objective function. Then, the objective function is approximated by a convex function and the integer programming problem is solved by means of constraint relaxation techniques. The proposed algorithms are suboptimal due to the approximate objective function and the constraint relaxation steps. However, they perform better than the conventional finger selection algorithm, which is suboptimal since it ignores the correlation between multipath components, and they can get quite close to the optimal scheme that cannot be implemented in practice due to its complexity. In addition to the convex relaxation techniques, a genetic-algorithm- (GA- based approach is proposed, which does not need any approximations or integer relaxations. This iterative algorithm is based on the direct evaluation of the objective function, and can achieve near-optimal performance with a reasonable number of iterations. Simulation results are presented to compare the performance of the proposed finger selection algorithms with that of the conventional and the optimal schemes.

NCCDS configuration management process improvement

Science.gov (United States)

Shay, Kathy

1993-01-01

By concentrating on defining and improving specific Configuration Management (CM) functions, processes, procedures, personnel selection/development, and tools, internal and external customers received improved CM services. Job performance within the section increased in both satisfaction and output. Participation in achieving major improvements has led to the delivery of consistent quality CM products as well as significant decreases in every measured CM metrics category.

Telemanipulator design and optimization software

Science.gov (United States)

Cote, Jean; Pelletier, Michel

1995-12-01

For many years, industrial robots have been used to execute specific repetitive tasks. In those cases, the optimal configuration and location of the manipulator only has to be found once. The optimal configuration or position where often found empirically according to the tasks to be performed. In telemanipulation, the nature of the tasks to be executed is much wider and can be very demanding in terms of dexterity and workspace. The position/orientation of the robot's base could be required to move during the execution of a task. At present, the choice of the initial position of the teleoperator is usually found empirically which can be sufficient in the case of an easy or repetitive task. In the converse situation, the amount of time wasted to move the teleoperator support platform has to be taken into account during the execution of the task. Automatic optimization of the position/orientation of the platform or a better designed robot configuration could minimize these movements and save time. This paper will present two algorithms. The first algorithm is used to optimize the position and orientation of a given manipulator (or manipulators) with respect to the environment on which a task has to be executed. The second algorithm is used to optimize the position or the kinematic configuration of a robot. For this purpose, the tasks to be executed are digitized using a position/orientation measurement system and a compact representation based on special octrees. Given a digitized task, the optimal position or Denavit-Hartenberg configuration of the manipulator can be obtained numerically. Constraints on the robot design can also be taken into account. A graphical interface has been designed to facilitate the use of the two optimization algorithms.

An optimally tuned ensemble of the "eb_go_gs" configuration of GENIE: parameter sensitivity and bifurcations in the Atlantic overturning circulation

Directory of Open Access Journals (Sweden)

R. Marsh

2013-10-01

Full Text Available The key physical parameters for the "eb_go_gs" configuration of version 2.7.4 of GENIE, an Earth system model of intermediate complexity (EMIC, are tuned using a multi-objective genetic algorithm. An ensemble of 90 parameter sets is tuned using two ocean and two atmospheric state variables as targets. These are "Pareto-optimal", representing a range of trade-offs between the four tuning targets. For the leading five parameter sets, simulations are evaluated alongside a simulation with untuned "default" parameters, comparing selected variables and diagnostics that describe the state of the atmosphere, ocean and sea ice. Further experiments are undertaken with these selected parameter sets to compare equilibrium climate sensitivities and transient climate responses. The pattern of warming under doubled CO2 is strongly shaped by changes in the Atlantic meridional overturning circulation (AMOC, while the pattern and rate of warming under rising CO2 is closely linked to changing sea ice extent. One of the five tuned parameter sets is identified as marginally optimal, and the objective function (error landscape is further analysed in the vicinity of the tuned values of this parameter set. "Cliffs" along some dimensions motivate closer inspection of corresponding variations in the AMOC. This reveals that bifurcations in the AMOC are highly sensitive to parameters that are not typically associated with MOC stability. Specifically, the state of the AMOC is sensitive to parameters governing the wind-driven circulation and atmospheric heat transport. For the GENIE configuration presented here, the marginally optimal parameter set is recommended for single simulations, although the leading five parameter sets may be used in ensemble mode to admit a constrained degree of parametric uncertainty in climate prediction.

Solar thermal central receivers

International Nuclear Information System (INIS)

Vant-Hull, L.L.

1993-01-01

Market issues, environmental impact, and technology issues related to the Solar Central Receiver concept are addressed. The rationale for selection of the preferred configuration and working fluid are presented as the result of a joint utility-industry analysis. A $30 million conversion of Solar One to an external molten salt receiver would provide the intermediate step to a commercial demonstration plant. The first plant in this series could produce electricity at 11.2 cents/kWhr and the seventh at 8.2 cents/kWhr, completely competitive with projected costs of new utility plants in 1992

Optimization of heliostat field layout in solar central receiver systems on annual basis using differential evolution algorithm

International Nuclear Information System (INIS)

Atif, Maimoon; Al-Sulaiman, Fahad A.

2015-01-01

Highlights: • Differential evolution optimization model was developed to optimize the heliostat field. • Five optical parameters were considered for the optimization of the optical efficiency. • Optimization using insolation weighted and un-weighted annual efficiency are developed. • The daily averaged annual optical efficiency was calculated to be 0.5023 while the monthly was 0.5025. • The insolation weighted daily averaged annual efficiency was 0.5634. - Abstract: Optimization of a heliostat field is an essential task to make a solar central receiver system effective because major optical losses are associated with the heliostat fields. In this study, a mathematical model was developed to effectively optimize the heliostat field on annual basis using differential evolution, which is an evolutionary algorithm. The heliostat field layout optimization is based on the calculation of five optical performance parameters: the mirror or the heliostat reflectivity, the cosine factor, the atmospheric attenuation factor, the shadowing and blocking factor, and the intercept factor. This model calculates all the aforementioned performance parameters at every stage of the optimization, until the best heliostat field layout based on annual performance is obtained. Two different approaches were undertaken to optimize the heliostat field layout: one with optimizing insolation weighted annual efficiency and the other with optimizing the un-weighted annual efficiency. Moreover, an alternate approach was also proposed to efficiently optimize the heliostat field in which the number of computational time steps was considerably reduced. It was observed that the daily averaged annual optical efficiency was calculated to be 0.5023 as compared to the monthly averaged annual optical efficiency, 0.5025. Moreover, the insolation weighted daily averaged annual efficiency of the heliostat field was 0.5634 for Dhahran, Saudi Arabia. The code developed can be used for any other

Detailed Configuration of the Underthrusting Indian Lithosphere Beneath Western Tibet Revealed by Receiver Function Images

Science.gov (United States)

Xu, Qiang; Zhao, Junmeng; Yuan, Xiaohui; Liu, Hongbing; Pei, Shunping

2017-10-01

We analyze the teleseismic waveform data recorded by 42 temporary stations from the Y2 and ANTILOPE-1 arrays using the P and S receiver function techniques to investigate the lithospheric structure beneath western Tibet. The Moho is reliably identified as a prominent feature at depths of 55-82 km in the stacked traces and in depth migrated images. It has a concave shape and reaches the deepest location at about 80 km north of the Indus-Yarlung suture (IYS). An intracrustal discontinuity is observed at 55 km depth below the southern Lhasa terrane, which could represent the upper border of the eclogitized underthrusting Indian lower crust. Underthrusting of the Indian crust has been widely observed beneath the Lhasa terrane and correlates well with the Bouguer gravity low, suggesting that the gravity anomalies in the Lhasa terrane are induced by topography of the Moho. At 20 km depth, a midcrustal low-velocity zone (LVZ) is observed beneath the Tethyan Himalaya and southern Lhasa terrane, suggesting a layer of partial melts that decouples the thrust/fold deformation of the upper crust from the shortening and underthrusting in the lower crust. The Sp conversions at the lithosphere-asthenosphere boundary (LAB) can be recognized at depths of 130-200 km, showing that the Indian lithospheric mantle is underthrusting with a ramp-flat shape beneath southern Tibet and probably is detached from the lower crust immediately under the IYS. Our observations reconstruct the configuration of the underthrusting Indian lithosphere and indicate significant along strike variations.

Microsoft System Center Configuration Manager

CERN Document Server

Sandbu, Marius

2013-01-01

This book is a step-by-step tutorial that guides you through the key steps in implementing best solutions for high availability and performance tuning. It is split into two distinct approaches: client and site side HA and optimization.Microsoft SCCM High Availability and Performance Tuning is for IT professionals and consultants working with Configuration Manager who wish to learn the skills to deploy a redundant and scalable solution.

Configuration model of partial repairable spares under batch ordering policy based on inventory state

Institute of Scientific and Technical Information of China (English)

Ruan Minzhi; Luo Yi; Li Hua

2014-01-01

Rational planning of spares configuration project is an effective approach to improve equipment availability as well as reduce life cycle cost (LCC). With an analysis of various impacts on support system, the spares demand rate forecast model is constructed. According to systemic analysis method, spares support effectiveness evaluation indicators system is built, and then, initial spares configuration and optimization method is researched. To the issue of discarding and con-sumption for incomplete repairable items, its expected backorders function is approximated by Laplace demand distribution. Combining the (s-1, s) and (R, Q) inventory policy, the spares resup-ply model is established under the batch ordering policy based on inventory state, and the optimi-zation analysis flow for spares configuration is proposed. Through application on shipborne equipment spares configuration, the given scenarios are analyzed under two constraint targets:one is the support effectiveness, and the other is the spares cost. Analysis reveals that the result is consistent with practical regulation;therefore, the model’s correctness, method’s validity as well as optimization project’s rationality are proved to a certain extent.

Optimizing Availability of a Framework in Series Configuration Utilizing Markov Model and Monte Carlo Simulation Techniques

Directory of Open Access Journals (Sweden)

Mansoor Ahmed Siddiqui

2017-06-01

Full Text Available This research work is aimed at optimizing the availability of a framework comprising of two units linked together in series configuration utilizing Markov Model and Monte Carlo (MC Simulation techniques. In this article, effort has been made to develop a maintenance model that incorporates three distinct states for each unit, while taking into account their different levels of deterioration. Calculations are carried out using the proposed model for two distinct cases of corrective repair, namely perfect and imperfect repairs, with as well as without opportunistic maintenance. Initially, results are accomplished using an analytical technique i.e., Markov Model. Validation of the results achieved is later carried out with the help of MC Simulation. In addition, MC Simulation based codes also work well for the frameworks that follow non-exponential failure and repair rates, and thus overcome the limitations offered by the Markov Model.

An Integrated Method for Airfoil Optimization

Science.gov (United States)

Okrent, Joshua B.

Design exploration and optimization is a large part of the initial engineering and design process. To evaluate the aerodynamic performance of a design, viscous Navier-Stokes solvers can be used. However this method can prove to be overwhelmingly time consuming when performing an initial design sweep. Therefore, another evaluation method is needed to provide accurate results at a faster pace. To accomplish this goal, a coupled viscous-inviscid method is used. This thesis proposes an integrated method for analyzing, evaluating, and optimizing an airfoil using a coupled viscous-inviscid solver along with a genetic algorithm to find the optimal candidate. The method proposed is different from prior optimization efforts in that it greatly broadens the design space, while allowing the optimization to search for the best candidate that will meet multiple objectives over a characteristic mission profile rather than over a single condition and single optimization parameter. The increased design space is due to the use of multiple parametric airfoil families, namely the NACA 4 series, CST family, and the PARSEC family. Almost all possible airfoil shapes can be created with these three families allowing for all possible configurations to be included. This inclusion of multiple airfoil families addresses a possible criticism of prior optimization attempts since by only focusing on one airfoil family, they were inherently limiting the number of possible airfoil configurations. By using multiple parametric airfoils, it can be assumed that all reasonable airfoil configurations are included in the analysis and optimization and that a global and not local maximum is found. Additionally, the method used is amenable to customization to suit any specific needs as well as including the effects of other physical phenomena or design criteria and/or constraints. This thesis found that an airfoil configuration that met multiple objectives could be found for a given set of nominal

A low emittance configuration for spear

International Nuclear Information System (INIS)

Blumberg, L.N.; Cerino, J.; Harris, J.; Hettel, R.; Hofmann, A.; Liu, R.Z.; Stego, R.; Wiedemann, H.; Winick, H.

1985-01-01

The quality of synchrotron radiation beams from SPEAR, in particular the brilliance of undulator radiation, can be improved significantly by reducing the emittance of the stored electron beam. A reduction of the horizontal emittance by a factor of 3.5 to a value of 130 nanometer-radians (nm-r) at 3 GeV has been achieved by using stronger focussing, mainly in the horizontal plane. The low emittance configuration also reduces the dispersion and vertical beta functions in the straight sections, making them more suitable for wigglers. The higher betatron tunes lead to a larger phase advance between the two kickers, which has to be corrected during injection by shunting current from some quadrupoles. The configuration was optimized within SPEAR hardware limitations and tested for dynamic aperture with the tracking program PATRICIA. After implementation of this scheme, beam was successfully injected and accumulated. The measured emittance of the stored beam was in agreement with calculations. Presently the configuration is being made operational

Routing performance analysis and optimization within a massively parallel computer

Science.gov (United States)

Archer, Charles Jens; Peters, Amanda; Pinnow, Kurt Walter; Swartz, Brent Allen

2013-04-16

An apparatus, program product and method optimize the operation of a massively parallel computer system by, in part, receiving actual performance data concerning an application executed by the plurality of interconnected nodes, and analyzing the actual performance data to identify an actual performance pattern. A desired performance pattern may be determined for the application, and an algorithm may be selected from among a plurality of algorithms stored within a memory, the algorithm being configured to achieve the desired performance pattern based on the actual performance data.

Energy savings in distillation via identification of useful configurations

Science.gov (United States)

Shah, Vishesh Hemanshu

Recent market and environmental forces require the rapid development of better and cheaper separation process solutions. Especially for multicomponent mixtures, there are several feasible separation process solutions differing significantly in cost and energy consumption in spite of carrying out the same overall process. Therefore a systematic method to identify and design optimal multicomponent separation sequences is needed instead of relying on the inventive activity of a few experienced engineers. Even for a commonly perceived "mature" technology such as distillation, until recently there has been an absence of systematic methods to (i) elucidate all possible separation configurations and to (ii) identify energy efficient candidates. This research aims to address these needs. In this work, we focus on the continuous distillation of non-azeotropic mixtures into n distinct composition final product streams. We develop a computationally efficient and easy-to-use mathematical framework to generate all the basic distillation configurations that use exactly (n-1) distillation columns to carry out this n-component separation. We extend the framework to generate all the additional distillation configurations with thermal coupling. We observe that the search space of distillation configurations grows very rapidly as the number of product streams increases. For instance, for a mixture to be separated into 4 product streams, we can choose from 18 basic configurations and 134 additional configurations with thermal coupling; while for a mixture to be separated into 8 product streams, we can choose from 15,767,207 basic configurations and 29,006,926,681 additional configurations with thermal coupling. The next challenge for a process engineer is to be able to quickly prune the search space to a handful of attractive energy efficient candidates that can be studied in greater detail. To this effect, we develop a quick screening optimization tool that identifies configurations

Performance comparison of different thermodynamic cycles for an innovative central receiver solar power plant

Science.gov (United States)

Reyes-Belmonte, Miguel A.; Sebastián, Andrés; González-Aguilar, José; Romero, Manuel

2017-06-01

The potential of using different thermodynamic cycles coupled to a solar tower central receiver that uses a novel heat transfer fluid is analyzed. The new fluid, named as DPS, is a dense suspension of solid particles aerated through a tubular receiver used to convert concentrated solar energy into thermal power. This novel fluid allows reaching high temperatures at the solar receiver what opens a wide range of possibilities for power cycle selection. This work has been focused into the assessment of power plant performance using conventional, but optimized cycles but also novel thermodynamic concepts. Cases studied are ranging from subcritical steam Rankine cycle; open regenerative Brayton air configurations at medium and high temperature; combined cycle; closed regenerative Brayton helium scheme and closed recompression supercritical carbon dioxide Brayton cycle. Power cycle diagrams and working conditions for design point are compared amongst the studied cases for a common reference thermal power of 57 MWth reaching the central cavity receiver. It has been found that Brayton air cycle working at high temperature or using supercritical carbon dioxide are the most promising solutions in terms of efficiency conversion for the power block of future generation by means of concentrated solar power plants.

Actively controlling coolant-cooled cold plate configuration

Science.gov (United States)

Chainer, Timothy J.; Parida, Pritish R.

2015-07-28

A method is provided to facilitate active control of thermal and fluid dynamic performance of a coolant-cooled cold plate. The method includes: monitoring a variable associated with at least one of the coolant-cooled cold plate or one or more electronic components being cooled by the cold plate; and dynamically varying, based on the monitored variable, a physical configuration of the cold plate. By dynamically varying the physical configuration, the thermal and fluid dynamic performance of the cold plate are adjusted to, for example, optimally cool the one or more electronic components, and at the same time, reduce cooling power consumption used in cooling the electronic component(s). The physical configuration can be adjusted by providing one or more adjustable plates within the coolant-cooled cold plate, the positioning of which may be adjusted based on the monitored variable.

Optimal Integration of Cascade Thermoelectric Cooler into Electronic Housing: Experimental Approach

Science.gov (United States)

Semeniuk, V.; Protsenko, D.

2018-06-01

The problem of the optimal integration of thermoelectrically cooled optoelectronic components into an electronic housing is studied with the emphasis on practical implementation. The lines of 2-stage and 3-stage thermoelectric coolers (TECs) compatible with TO8 housing have been developed, and their parameters are measured in a wide range of heat sink temperatures. The TECs are optimized to receive a temperature difference of 100-110 K under a heat load from 70 mW to 100 mW with minimal power consumption. To fit into a standard housing interior, all the TECs have the same overall dimensions, regardless of the number of stages. Details of the TEC configurations and their performance characteristics are presented and discussed.

Strategies to optimize lithium-ion supercapacitors achieving high-performance: Cathode configurations, lithium loadings on anode, and types of separator

Science.gov (United States)

Cao, Wanjun; Li, Yangxing; Fitch, Brian; Shih, Jonathan; Doung, Tien; Zheng, Jim

2014-12-01

The Li-ion capacitor (LIC) is composed of a lithium-doped carbon anode and an activated carbon cathode, which is a half Li-ion battery (LIB) and a half electrochemical double-layer capacitor (EDLC). LICs can achieve much more energy density than EDLC without sacrificing the high power performance advantage of capacitors over batteries. LIC pouch cells were assembled using activated carbon (AC) cathode and hard carbon (HC) + stabilized lithium metal power (SLMP®) anode. Different cathode configurations, various SLMP loadings on HC anode, and two types of separators were investigated to achieve the optimal electrochemical performance of the LIC. Firstly, the cathode binders study suggests that the PTFE binder offers improved energy and power performances for LIC in comparison to PVDF. Secondly, the mass ratio of SLMP to HC is at 1:7 to obtain the optimized electrochemical performance for LIC among all the various studied mass ratios between lithium loading amounts and active anode material. Finally, compared to the separator Celgard PP 3501, cellulose based TF40-30 is proven to be a preferred separator for LIC.

Software Configurable Multichannel Transceiver

Science.gov (United States)

Freudinger, Lawrence C.; Cornelius, Harold; Hickling, Ron; Brooks, Walter

2009-01-01

Emerging test instrumentation and test scenarios increasingly require network communication to manage complexity. Adapting wireless communication infrastructure to accommodate challenging testing needs can benefit from reconfigurable radio technology. A fundamental requirement for a software-definable radio system is independence from carrier frequencies, one of the radio components that to date has seen only limited progress toward programmability. This paper overviews an ongoing project to validate the viability of a promising chipset that performs conversion of radio frequency (RF) signals directly into digital data for the wireless receiver and, for the transmitter, converts digital data into RF signals. The Software Configurable Multichannel Transceiver (SCMT) enables four transmitters and four receivers in a single unit the size of a commodity disk drive, programmable for any frequency band between 1 MHz and 6 GHz.

Optimization of a scintillation detector with hemispherical configuration

International Nuclear Information System (INIS)

Saules Mendonca, A.C. de.

1980-08-01

A hemispherical configuration for scintillation detectors, is introduced so as to minimize the dispersion in light collection by reducing the number of reflexions. Better results in the process of light collection appear explicitly in the gain in the amplitude of the pulse and a better resolution in time and energy when a comparative analysis is made between the cylindrical and hemispherical geometries. The measurements were made using NE102, a plastic scintillator with cylindrical and hemispherical forms, comparing the results of pulse amplitude and energy resolution. The results were quite significant showing a 13% improvement in pulse amplitude and more than 10% in energy resolution for some values of energies from 511 KeV to 1275 KeV. (Author) [pt

Final Report - Testing of Optimized Bubbler Configuration for HLW Melter VSL-13R2950-1, Rev. 0, dated 6/12/2013

Energy Technology Data Exchange (ETDEWEB)

Kruger, Albert A.; Pegg, I. L.; Callow, R. A.; Joseph, I.; Matlack, K. S.; Kot, W. K.

2013-11-13

The principal objective of this work was to determine the glass production rate increase and ancillary effects of adding more bubbler outlets to the current WTP HLW melter baseline. This was accomplished through testing on the HLW Pilot Melter (DM1200) at VSL. The DM1200 unit was selected for these tests since it was used previously with several HLW waste streams including the four tank wastes proposed for initial processing at Hanford. This melter system was also used for the development and optimization of the present baseline WTP HLW bubbler configuration for the WTP HLW melter, as well as for MACT testing for both HLW and LAW. Specific objectives of these tests were to: Conduct DM1200 melter testing with the baseline WTP bubbling configuration and as augmented with additional bubblers. Conduct DM1200 melter testing to differentiate the effects of total bubbler air flow and bubbler distribution on glass production rate and cold cap formation. Collect melter operating data including processing rate, temperatures at a variety of locations within the melter plenum space, melt pool temperature, glass melt density, and melter pressure with the baseline WTP bubbling configuration and as augmented with additional bubblers. Collect melter exhaust samples to compare particulate carryover for different bubbler configurations. Analyze all collected data to determine the effects of adding more bubblers to the WTP HLW melter to inform decisions regarding future lid re-designs. The work used a high aluminum HLW stream composition defined by ORP, for which an appropriate simulant and high waste loading glass formulation were developed and have been previously processed on the DM1200.

IMPROVEMENT WAYS OF ACCOUNTING AND INTERNAL AUDIT OF ENTERPRISE RECEIVABLES

Directory of Open Access Journals (Sweden)

V. D. Zelikman

2014-06-01

Full Text Available Purpose. Determination and substantiation of ways to improve accounting and internal audit of receivables at the enterprises. Methodology.The basic principles and ways for improvement of accounting and internal audit systems that should help Ukrainian enterprises to optimize receivables are considered. Findings. It is proved that the receivables optimization is possible on the basis of improving its accounting and internal audit. The basic ways for improvement of accounting and internal audit of receivable are determined. They are: improvement of normative coverage of receivables at the enterprises; providing further harmonization of financial and tax accounting in the part of formation of the doubtful debt receivables, accounting of bad and doubtful receivables and etc. The formation of department for internal audit to control the doubtful and bad debts; providing the timely control of the receivables and payables ratio; determination and support of the optimal value of the receivables at the enterprises. Originality. Improvement of accounting and internal audit of receivables at the enterprises by the way of development of internal audit system and optimization of the receivables size. Practical value. The proposed recommendations will improve the accounting and internal audit system of receivables at the enterprises of Ukraine.

Genetic evolutionary taboo search for optimal marker placement in infrared patient setup

International Nuclear Information System (INIS)

Riboldi, M; Baroni, G; Spadea, M F; Tagaste, B; Garibaldi, C; Cambria, R; Orecchia, R; Pedotti, A

2007-01-01

In infrared patient setup adequate selection of the external fiducial configuration is required for compensating inner target displacements (target registration error, TRE). Genetic algorithms (GA) and taboo search (TS) were applied in a newly designed approach to optimal marker placement: the genetic evolutionary taboo search (GETS) algorithm. In the GETS paradigm, multiple solutions are simultaneously tested in a stochastic evolutionary scheme, where taboo-based decision making and adaptive memory guide the optimization process. The GETS algorithm was tested on a group of ten prostate patients, to be compared to standard optimization and to randomly selected configurations. The changes in the optimal marker configuration, when TRE is minimized for OARs, were specifically examined. Optimal GETS configurations ensured a 26.5% mean decrease in the TRE value, versus 19.4% for conventional quasi-Newton optimization. Common features in GETS marker configurations were highlighted in the dataset of ten patients, even when multiple runs of the stochastic algorithm were performed. Including OARs in TRE minimization did not considerably affect the spatial distribution of GETS marker configurations. In conclusion, the GETS algorithm proved to be highly effective in solving the optimal marker placement problem. Further work is needed to embed site-specific deformation models in the optimization process

Effect of Neoclassical Transport Optimization on Energetic Ion Confinement in LHD

International Nuclear Information System (INIS)

Murakami, S.; Yamada, H.; Sasao, M.

2004-01-01

Confinement of energetic ions from neutral beam injection heating is investigated by changing the magnetic field configuration of the Large Helical Device from a classical heliotron configuration to an optimized neoclassical transport configuration to a level typical of ''advanced stellarators.'' The experimental results show the highest count rate of fast neutral particles not in the optimized configuration but in the inward-shifted one. The GNET simulation results show a relatively good agreement with the experimental results, and they also show a lower energy loss rate in the optimized configuration. This contradiction can be explained by the radial profile of the energetic ions. The relatively good agreement between experimental and simulation results suggest that ripple transport (neoclassical) dominates the energetic ion confinement and that the optimization process is effective in improving confinement in helical systems

Efficient receiver tuning using differential evolution strategies

Science.gov (United States)

Wheeler, Caleb H.; Toland, Trevor G.

2016-08-01

Differential evolution (DE) is a powerful and computationally inexpensive optimization strategy that can be used to search an entire parameter space or to converge quickly on a solution. The Kilopixel Array Pathfinder Project (KAPPa) is a heterodyne receiver system delivering 5 GHz of instantaneous bandwidth in the tuning range of 645-695 GHz. The fully automated KAPPa receiver test system finds optimal receiver tuning using performance feedback and DE. We present an adaptation of DE for use in rapid receiver characterization. The KAPPa DE algorithm is written in Python 2.7 and is fully integrated with the KAPPa instrument control, data processing, and visualization code. KAPPa develops the technologies needed to realize heterodyne focal plane arrays containing 1000 pixels. Finding optimal receiver tuning by investigating large parameter spaces is one of many challenges facing the characterization phase of KAPPa. This is a difficult task via by-hand techniques. Characterizing or tuning in an automated fashion without need for human intervention is desirable for future large scale arrays. While many optimization strategies exist, DE is ideal for time and performance constraints because it can be set to converge to a solution rapidly with minimal computational overhead. We discuss how DE is utilized in the KAPPa system and discuss its performance and look toward the future of 1000 pixel array receivers and consider how the KAPPa DE system might be applied.

User's manual for DELSOL2: a computer code for calculating the optical performance and optimal system design for solar-thermal central-receiver plants

Energy Technology Data Exchange (ETDEWEB)

Dellin, T.A.; Fish, M.J.; Yang, C.L.

1981-08-01

DELSOL2 is a revised and substantially extended version of the DELSOL computer program for calculating collector field performance and layout, and optimal system design for solar thermal central receiver plants. The code consists of a detailed model of the optical performance, a simpler model of the non-optical performance, an algorithm for field layout, and a searching algorithm to find the best system design. The latter two features are coupled to a cost model of central receiver components and an economic model for calculating energy costs. The code can handle flat, focused and/or canted heliostats, and external cylindrical, multi-aperture cavity, and flat plate receivers. The program optimizes the tower height, receiver size, field layout, heliostat spacings, and tower position at user specified power levels subject to flux limits on the receiver and land constraints for field layout. The advantages of speed and accuracy characteristic of Version I are maintained in DELSOL2.

Performance investigation of solid desiccant evaporative cooling system configurations in different climatic zones

International Nuclear Information System (INIS)

Ali, Muzaffar; Vukovic, Vladimir; Sheikh, Nadeem Ahmed; Ali, Hafiz M.

2015-01-01

Highlights: • Five configurations of a DEC system are analyzed in five climate zones. • DEC system model configurations are developed in Dymola/Modelica. • Performance analysis predicted a suitable DEC system configuration for each climate zone. • Results show that climate of Vienna, Sao Paulo, and Adelaide favors the ventilated-dunkle cycle. • While ventilation cycle configuration suits the climate of Karachi and Shanghai. - Abstract: Performance of desiccant evaporative cooling (DEC) system configurations is strongly influenced by the climate conditions and varies widely in different climate zones. Finding the optimal configuration of DEC systems for a specific climatic zone is tedious and time consuming. This investigation conducts performance analysis of five DEC system configurations under climatic conditions of five cities from different zones: Vienna, Karachi, Sao Paulo, Shanghai, and Adelaide. On the basis of operating cycle, three standard and two modified system configurations (ventilation, recirculation, dunkle cycles; ventilated-recirculation and ventilated-dunkle cycles) are analyzed in these five climate zones. Using an advance equation-based object-oriented (EOO) modeling and simulation approach, optimal configurations of a DEC system are determined for each climate zone. Based on the hourly climate data of each zone for its respective design cooling day, performance of each system configuration is estimated using three performance parameters: cooling capacity, COP, and cooling energy delivered. The results revealed that the continental/micro-thermal climate of Vienna, temperate/mesothermal climate of Sao Paulo, and dry-summer subtropical climate of Adelaide favor the use of ventilated-dunkle cycle configuration with average COP of 0.405, 0.89 and 1.01 respectively. While ventilation cycle based DEC configuration suits arid and semiarid climate of Karachi and another category of temperate/mesothermal climate of Shanghai with average COP of

Optimization of a bundle divertor for FED

International Nuclear Information System (INIS)

Hively, L.M.; Rothe, K.E.; Minkoff, M.

1982-01-01

Optimal double-T bundle divertor configurations have been obtained for the Fusion Engineering Device (FED). On-axis ripple is minimized, while satisfying a series of engineering constraints. The ensuing non-linear optimization problem is solved via a sequence of quadratic programming subproblems, using the VMCON algorithm. The resulting divertor designs are substantially improved over previous configurations

Impact of the coupling effect and the configuration on a compact rectenna array

Science.gov (United States)

Rivière, J.; Douyere, A.; Luk, J. D. Lan Sun

2014-10-01

This paper proposes an experimental study of the coupling effect of a rectenna array. The rectifying antenna consists of a compact and efficient rectifying circuit in a series topology, coupled with a small metamaterial-inspired antenna. The measurements are investigated in the X plane on the rectenna array's behavior, with series and parallel DC- combining configuration of two and three spaced rectennas from 3 cm to 10 cm. This study shows that the maximum efficiency is reached for the series configuration, with a resistive load of 10 kQ. The optimal distance is not significant for series or parallel configuration. Then, a comparison between a rectenna array with non-optimal mutual coupling and a more traditional patch rectenna is performed. Finally, a practical application is tested to demonstrate the effectiveness of such small rectenna array.

Optimal dynamic performance for high-precision actuators/stages

International Nuclear Information System (INIS)

Preissner, C.; Lee, S.-H.; Royston, T. J.; Shu, D.

2002-01-01

System dynamic performance of actuator/stage groups, such as those found in optical instrument positioning systems and other high-precision applications, is dependent upon both individual component behavior and the system configuration. Experimental modal analysis techniques were implemented to determine the six degree of freedom stiffnesses and damping for individual actuator components. These experimental data were then used in a multibody dynamic computer model to investigate the effect of stage group configuration. Running the computer model through the possible stage configurations and observing the predicted vibratory response determined the optimal stage group configuration. Configuration optimization can be performed for any group of stages, provided there is stiffness and damping data available for the constituent pieces

Thermodynamic optimization of power plants

NARCIS (Netherlands)

Haseli, Y.

2011-01-01

Thermodynamic Optimization of Power Plants aims to establish and illustrate comparative multi-criteria optimization of various models and configurations of power plants. It intends to show what optimization objectives one may define on the basis of the thermodynamic laws, and how they can be applied

{sup 6}LiF:ZnS(Ag) Neutrons Scintillator Detector Configuration for Optimal Readout

Energy Technology Data Exchange (ETDEWEB)

Osovizky, A. [NIST Center for Neutron Research, Gaithersburg, Maryland (United States); Rotem Industries Ltd, Rotem Industrial Park (Israel); University of Maryland, College park, Maryland (United States); Yehuda-Zada, Y.; Ghelman, M.; Tsai, P.; Thompson, A.K. [Nuclear Research Center Negev, Beer-Sheva (Israel); Pritchard, K.; Ziegler, J.B.; Ibberson, R.M.; Majkrzak, C.F.; Maliszewskyj, N.C. [NIST Center for Neutron Research, Gaithersburg, Maryland (United States)

2015-07-01

A Chromatic Analysis Neutron Diffractometer Or Reflectometer (CANDOR) is under development at the NIST Center for Neutron Research (NCNR). The CANDOR neutron sensor will rely on scintillator material for detecting the neutrons scattered by the sample under test. It consists of {sup 6}LiF:ZnS(Ag) scintillator material into which wavelength shifting (WLS) fibers have been embedded. Solid state photo-sensors (silicon photomultipliers) coupled to the WLS fibers are used to detect the light produced by the neutron capture event ({sup 6}Li (n,α) {sup 3}H reaction) and ionization of the ZnS(Ag). This detector configuration has the potential to accomplish the CANDOR performance requirements for efficiency of 90% for 5 A (3.35 meV) neutrons with high gamma rejection (10{sup 7}) along with compact design, affordable cost and materials availability. However this novel design includes challenges for precise neutron detection. The recognizing of the neutron signature versus the noise event produce by gamma event cannot be easy overcome by pulse height discrimination obstacle as can be achieved with {sup 3}He gas tube. Furthermore the selection of silicon photomultipliers (SiPM) as the light sensor maintains the obstacle of dark noise that does not exist when a photomultiplier tube is coupled to the scintillator. A proper selection of SiPM should focus on increasing the output signal and reducing the dark noise in order to optimize the detection sensitivity and to provide a clean signal pulse shape discrimination. The main parameters for evaluation are: - Quantum Efficiency (QE) - matching the SiPM peak QE with the peak transmission wavelength emission of the WLS. - Recovery time - a short recovery time is preferred to minimize the pulse width beyond the intrinsic decay time of the scintillator crystal (improves the gamma rejection based output pulse shape (time)). - Diode dimensions -The dark noise is proportional to the diode active area while the signal is provided by the

Beam configuration selection for robust intensity-modulated proton therapy in cervical cancer using Pareto front comparison.

Science.gov (United States)

van de Schoot, A J A J; Visser, J; van Kesteren, Z; Janssen, T M; Rasch, C R N; Bel, A

2016-02-21

The Pareto front reflects the optimal trade-offs between conflicting objectives and can be used to quantify the effect of different beam configurations on plan robustness and dose-volume histogram parameters. Therefore, our aim was to develop and implement a method to automatically approach the Pareto front in robust intensity-modulated proton therapy (IMPT) planning. Additionally, clinically relevant Pareto fronts based on different beam configurations will be derived and compared to enable beam configuration selection in cervical cancer proton therapy. A method to iteratively approach the Pareto front by automatically generating robustly optimized IMPT plans was developed. To verify plan quality, IMPT plans were evaluated on robustness by simulating range and position errors and recalculating the dose. For five retrospectively selected cervical cancer patients, this method was applied for IMPT plans with three different beam configurations using two, three and four beams. 3D Pareto fronts were optimized on target coverage (CTV D(99%)) and OAR doses (rectum V30Gy; bladder V40Gy). Per patient, proportions of non-approved IMPT plans were determined and differences between patient-specific Pareto fronts were quantified in terms of CTV D(99%), rectum V(30Gy) and bladder V(40Gy) to perform beam configuration selection. Per patient and beam configuration, Pareto fronts were successfully sampled based on 200 IMPT plans of which on average 29% were non-approved plans. In all patients, IMPT plans based on the 2-beam set-up were completely dominated by plans with the 3-beam and 4-beam configuration. Compared to the 3-beam set-up, the 4-beam set-up increased the median CTV D(99%) on average by 0.2 Gy and decreased the median rectum V(30Gy) and median bladder V(40Gy) on average by 3.6% and 1.3%, respectively. This study demonstrates a method to automatically derive Pareto fronts in robust IMPT planning. For all patients, the defined four-beam configuration was found optimal

Beam configuration selection for robust intensity-modulated proton therapy in cervical cancer using Pareto front comparison

International Nuclear Information System (INIS)

Van de Schoot, A J A J; Visser, J; Van Kesteren, Z; Rasch, C R N; Bel, A; Janssen, T M

2016-01-01

The Pareto front reflects the optimal trade-offs between conflicting objectives and can be used to quantify the effect of different beam configurations on plan robustness and dose-volume histogram parameters. Therefore, our aim was to develop and implement a method to automatically approach the Pareto front in robust intensity-modulated proton therapy (IMPT) planning. Additionally, clinically relevant Pareto fronts based on different beam configurations will be derived and compared to enable beam configuration selection in cervical cancer proton therapy. A method to iteratively approach the Pareto front by automatically generating robustly optimized IMPT plans was developed. To verify plan quality, IMPT plans were evaluated on robustness by simulating range and position errors and recalculating the dose. For five retrospectively selected cervical cancer patients, this method was applied for IMPT plans with three different beam configurations using two, three and four beams. 3D Pareto fronts were optimized on target coverage (CTV D 99% ) and OAR doses (rectum V 30Gy ; bladder V 40Gy ). Per patient, proportions of non-approved IMPT plans were determined and differences between patient-specific Pareto fronts were quantified in terms of CTV D 99% , rectum V 30Gy and bladder V 40Gy to perform beam configuration selection. Per patient and beam configuration, Pareto fronts were successfully sampled based on 200 IMPT plans of which on average 29% were non-approved plans. In all patients, IMPT plans based on the 2-beam set-up were completely dominated by plans with the 3-beam and 4-beam configuration. Compared to the 3-beam set-up, the 4-beam set-up increased the median CTV D 99% on average by 0.2 Gy and decreased the median rectum V 30Gy and median bladder V 40Gy on average by 3.6% and 1.3%, respectively. This study demonstrates a method to automatically derive Pareto fronts in robust IMPT planning. For all patients, the defined four-beam configuration was found optimal in

Optimization of wide-area ATM and local-area ethernet/FDDI network configurations for high-speed telemedicine communications employing NASA's ACTS.

Science.gov (United States)

McDermott, W R; Tri, J L; Mitchell, M P; Levens, S P; Wondrow, M A; Huie, L M; Khandheria, B K; Gilbert, B K

1999-01-01

A high data rate terrestrial and satellite network was implemented to transfer medical images and data. This article describes the a optimization of the workstations and switching equipment incorporated into the network. Topics discussed in this article include tuning of the network software, the configuration of the Sun Microsystems workstations, the FORE Systems asynchronous transfer mode switches, as well as the throughput results of two telemedicine experiments undertaken by Mayo's physician staff. The technical staff was successful in achieving the data throughput needed by the telemedicine software; particularly important was the proper determination of peak throughput and TCP window sizes to ensure optimum use of the resources available on the Sun Microsystems and Hewlett Packard workstations.

Time optimal paths for high speed maneuvering

Energy Technology Data Exchange (ETDEWEB)

Reister, D.B.; Lenhart, S.M.

1993-01-01

Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

Applying design principles to fusion reactor configurations for propulsion in space

International Nuclear Information System (INIS)

Carpenter, S.A.; Deveny, M.E.; Schulze, N.R.

1993-01-01

The application of fusion power to space propulsion requires rethinking the engineering-design solution to controlled-fusion energy. Whereas the unit cost of electricity (COE) drives the engineering-design solution for utility-based fusion reactor configurations; initial mass to low earth orbit (IMLEO), specific jet power (kW(thrust)/kg(engine)), and reusability drive the engineering-design solution for successful application of fusion power to space propulsion. Three design principles (DP's) were applied to adapt and optimize three candidate-terrestrial-fusion-reactor configurations for propulsion in space. The three design principles are: provide maximum direct access to space for waste radiation, operate components as passive radiators to minimize cooling-system mass, and optimize the plasma fuel, fuel mix, and temperature for best specific jet power. The three candidate terrestrial fusion reactor configurations are: the thermal barrier tandem mirror (TBTM), field reversed mirror (FRM), and levitated dipole field (LDF). The resulting three candidate space fusion propulsion systems have their IMLEO minimized and their specific jet power and reusability maximized. A preliminary rating of these configurations was performed, and it was concluded that the leading engineering-design solution to space fusion propulsion is a modified TBTM that we call the Mirror Fusion Propulsion System (MFPS)

Projective configurations in projectivegeometrical drawings

Directory of Open Access Journals (Sweden)

Ivashchenko Andrey Viktorovich

2015-05-01

Full Text Available The article focuses on the optimization of the earlier discussed computer method of obtaining new forms of polyhedra based on projective geometry drawings (trace Diagrams.While working on getting new multifaceted forms by projective geometry methods based on the well-known models of polyhedra on the first stage of the work it is required to calculate the parameters of projective geometry drawings, and then to build them. This is an often used apparatus of analytical geometry. According to it, at first the parameters of the polyhedron (core system of planes are calculated, then we obtain the equation of the plane of the face of the polyhedron, and finally we obtain the equations of lines the next plane faces on the selected curve plane. At each stage of application such a method requires the use of the algorithms of floating point arithmetic, on the one hand, leads to some loss of accuracy of the results and, on the other hand, the large amount of computer time to perform these operations in comparison with integer arithmetic operations.The proposed method is based on the laws existing between the lines that make up the drawing - the known configurations of projective geometry (complete quadrilaterals, configuration of Desargues, Pappus et al..The authors discussed in detail the analysis procedure of projective geometry drawing and the presence of full quadrilaterals, Desargues and Pappus configurations in it.Since the composition of these configurations is invariant with respect to projective change of the original nucleus, knowing them, you can avoid the calculations when solving the equations for finding direct projective geometry drawing analytically, getting them on the basis of belonging to a particular configuration. So you can get a definite advantage in accuracy of the results, and in the cost of computer time. Finding these basic configurations significantly enriches the set of methods and the use of projective geometry drawings.

Configuration Analysis of Plug-in Hybrid Systems using Global Optimization

OpenAIRE

Kim, Insup; Kim, Hyunsup

2013-01-01

The purpose of the study is to analyze the configurations of Plug-in Hybrid Electric Vehicles (PHEV) with respect to fuel economy. Existing studies mostly focus on hybrid systems or few PHEV systems by only considering power split ratio and component efficiency. This paper adds original contribution to these literatures. First of all, this study compares and analyzes “series + α” PHEV – Input split, Series-output split and Series-parallel, which is consisted of a single Planetary gear or spur...

Optimization of Passive Coherent Receiver System Placement

Science.gov (United States)

2013-09-01

spheroid object with a constant radar cross section (RCS). Additionally, the receiver and transmitters are assumed to be notional isotropic antennae...software- defined radio for equatorial plasma instability studies,” Radio Science, vol. 48, pp. 1–11. Aug. 2013. [2] P. C. Zhang and B. Y. Li, “Passive

Power Management Strategy by Enhancing the Mission Profile Configuration of Solar-Powered Aircraft

Directory of Open Access Journals (Sweden)

Parvathy Rajendran

2016-01-01

Full Text Available Solar energy offers solar-powered unmanned aerial vehicle (UAV the possibility of unlimited endurance. Some researchers have developed techniques to achieve perpetual flight by maximizing the power from the sun and by flying in accordance with its azimuth angles. However, flying in a path that follows the sun consumes more energy to sustain level flight. This study optimizes the overall power ratio by adopting the mission profile configuration of optimal solar energy exploitation. Extensive simulation is conducted to optimize and restructure the mission profile phases of UAV and to determine the optimal phase definition of the start, ascent, and descent periods, thereby maximizing the energy from the sun. In addition, a vertical cylindrical flight trajectory instead of maximizing the solar inclination angle has been adopted. This approach improves the net power ratio by 30.84% compared with other techniques. As a result, the battery weight may be massively reduced by 75.23%. In conclusion, the proposed mission profile configuration with the optimal power ratio of the trajectory of the path planning effectively prolongs UAV operation.

Optimization of feed water control for auxiliary boiler

International Nuclear Information System (INIS)

Li Lingmao

2004-01-01

This paper described the feed water control system of the auxiliary boiler steam drum in Qinshan Phase III Nuclear Power Plant, analyzed the deficiency of the original configuration, and proposed the optimized configuration. The optimized feed water control system can ensure the stable and safe operation of the auxiliary boiler, and the normal operation of the users. (author)

A practical tablet-based hearing aid configuration as an exemplar project for students of instrumentation

Directory of Open Access Journals (Sweden)

Ricardo Simeoni

2015-06-01

Full Text Available This paper presents the configuration and digital signal processing details of a tablet-based hearing aid transmitting wirelessly to standard earphones, whereby the tablet performs full sound processing rather than solely providing a means of setting adjustment by streaming to conventional digital hearing aids. The presented device confirms the recognized advantages of this tablet-based approach (e.g., in relation to cost, frequency domain processing, amplification range, versatility of functionality, component battery rechargeability, and flags the future wider-spread availability of such hearing solutions within mainstream healthcare. The use of a relatively high sampling frequency was found to be beneficial for device performance, while the use of optional off-the-shelf add-on components (e.g., data acquisition device, high fidelity microphone, compact wireless transmitter/ receiver, wired headphones are also discussed in relation to performance optimization. The easy-to-follow configuration utilized is well suited to student learning/research instrumentation projects within the health and biomedical sciences. In this latter regard, the presented device was pedagogically integrated into a flipped classroom approach for the teaching of bioinstrumentation within an Allied Health Sciences School, with the subsequent establishment of positive student engagement outcomes.

A Practical Tablet-Based Hearing Aid Configuration as an Exemplar Project for Students of Instrumentation.

Science.gov (United States)

Simeoni, Ricardo

2015-06-11

This paper presents the configuration and digital signal processing details of a tablet-based hearing aid transmitting wirelessly to standard earphones, whereby the tablet performs full sound processing rather than solely providing a means of setting adjustment by streaming to conventional digital hearing aids. The presented device confirms the recognized advantages of this tablet-based approach (e.g., in relation to cost, frequency domain processing, amplification range, versatility of functionality, component battery rechargeability), and flags the future wider-spread availability of such hearing solutions within mainstream healthcare. The use of a relatively high sampling frequency was found to be beneficial for device performance, while the use of optional off-the-shelf add-on components (e.g., data acquisition device, high fidelity microphone, compact wireless transmitter/receiver, wired headphones) are also discussed in relation to performance optimization. The easy-to-follow configuration utilized is well suited to student learning/research instrumentation projects within the health and biomedical sciences. In this latter regard, the presented device was pedagogically integrated into a flipped classroom approach for the teaching of bioinstrumentation within an Allied Health Sciences School, with the subsequent establishment of positive student engagement outcomes.

A demonstration of magnetic field optimization in LHD

Energy Technology Data Exchange (ETDEWEB)

Murakami, S.; Yamada, H. [National Inst. for Fusion Science, Toki, Gifu (Japan); Wakasa, A. [Hokkaido Univ., Graduate School of Engineering, Sapporo, Hokkaido (JP)] [and others

2002-11-01

An optimized configuration of the neoclassical transport and the energetic particle confinement to a level typical of so-called 'advanced stellarators' is found by shifting the magnetic axis position in LHD. Electron heat transport and NBI beam ion distribution are investigated in low-collisionality LHD plasma in order to study the magnetic field optimization effect on the thermal plasma transport and the energetic particle confinement. A higher electron temperature is obtained in the optimized configuration, and the transport analysis suggests a considerable effect of neoclassical transport on the electron heat transport assuming the ion-root level of radial electric field. Also a higher energetic ion distribution of NBI beam ions is observed showing the improvement of the energetic particle confinement. These obtained results support a future reactor design by magnetic field optimization in a non-axisymmetric configuration. (author)

A demonstration of magnetic field optimization in LHD

Energy Technology Data Exchange (ETDEWEB)

Murakami, S.; Yamada, H. [National Inst. for Fusion Science, Toki, Gifu (Japan); Wakasa, A. [Hokkaido Univ., Graduate School of Engineering, Sapporo, Hokkaido (JP)] [and others

2002-10-01

An optimized configuration of the neoclassical transport and the energetic particle confinement to a level typical of so-called 'advanced stellarators' is found by shifting the magnetic axis position in LHD. Electron heat transport and NBI beam ion distribution are investigated in low-collisionality LHD plasma in order to study the magnetic field optimization effect on the thermal plasma transport and the energetic particle confinement. A higher electron temperature is obtained in the optimized configuration, and the transport analysis suggests a considerable effect of neoclassical transport on the electron heat transport assuming the ion-root level of radial electric field. Also a higher energetic ion distribution of NBI beam ions is observed showing the improvement of the energetic particle confinement. These obtained results support a future reactor design by magnetic field optimization in a non-axisymmetric configuration. (author)

Efficient configurations for block ciphers with unified ENC/DEC paths

DEFF Research Database (Denmark)

Banik, Subhadeep; Bogdanov, Andrey; Regazzoni, Francesco

2017-01-01

by analyzing 12 circuit configurations for the Advanced Encryption Standard (AES-128) cipher and establish some design rules for energy efficiency. We then extend our analysis to several lightweight block ciphers. In the second part of the paper we also investigate area optimized circuits for combined......Block Ciphers providing the combined functionalities of encryption and decryption are required to operate in modes of operation like CBC and ELmD. Hence such architectures form critical building blocks for secure cryptographic implementations. Depending on the algebraic structure of a given cipher......, there may be multiple ways of constructing the combined encryption/decryption circuit, each targeted at optimizing lightweight design metrics like area or power etc. In this paper we look at how the choice of circuit configuration affects the energy required to perform one encryption/decryption. We begin...

Developments of methods for computerized configuration control

International Nuclear Information System (INIS)

Kafka, P.

1997-01-01

It is known that Probabilistic Safety Assessment (PSA) is nowadays the appropriate technology and tool that can be used to optimize, during the design phase, a considered installation taking into account reliability and safety aspects, and also to evaluate and quantify the base-line risk level for the optimized installation. This base-line risk level is normally expressed by an average frequency per plant-year assigned to a scenario of interest (e.g. core damage, in case of a NPP). A considerable number of changes in components and system design can occur during the construction phase and another during the subsequent operation phase due to a continuous change in the plant configurations and their operating procedures, when compared to the configuration considered for the base-line risk quantification. These changes can be originated by planned activities like tests, maintenance and repair or by unplanned actions, mainly random events (failures) on components and systems. This results in a fluctuation of the risk level over operating time and is denominated as the ''risk profile'' (RP) of the installation. Living PSA and risk monitoring programs can assess the RP. An adequate management tool, calculating the ''risk profile'', can be used to control and optimize the operation of the installation with respect to a minimal risk level over the operating time. As a result we obtained a so called fault tolerant operation. 30 refs, 1 tab, figs

Integrated reconfigurable microring based silicon WDM receiver for on-chip optical interconnect

International Nuclear Information System (INIS)

Shen, Ao; Yang, Long-Zhi; Dai, Ting-Ge; Hao, Yin-Lei; Jiang, Xiao-Qing; Yang, Jian-Yi; Qiu, Chen

2015-01-01

We demonstrate an integrated reconfigurable wavelength division multiplexing receiver on the silicon-on-insulator (SOI) platform. The receiver is composed of a 1 × 8 thermally tunable microring resonator filter and Ge–Si photodetectors. With low thermal tuning powers the channel allocation of the receiver can be reconfigured with high accuracy and flexibility. The thermal tuning efficiency is approximately 8 mW nm −1 . We show eight-channel configurations with channel spacing of 100 GHz and 50 GHz and a configuration in which all eight channels cover an entire free spectral range of the ring with uniform channel spacing of 1.2 nm. Each channel can receive high-quality signals with a data rate of up to 13.5 Gb s −1 ; thus an aggregate data rate higher than 100 Gb s −1 can be achieved. (paper)

Reliability analysis for dynamic configurations of systems with three failure modes

International Nuclear Information System (INIS)

Pham, Hoang

1999-01-01

Analytical models for computing the reliability of dynamic configurations of systems, such as majority and k-out-of-n, assuming that units and systems are subject to three types of failures: stuck-at-0, stuck-at-1, and stuck-at-x are presented in this paper. Formulas for determining the optimal design policies that maximize the reliability of dynamic k-out-of-n configurations subject to three types of failures are defined. The comparisons of the reliability modeling functions are also obtained. The optimum system size and threshold value k that minimize the expected cost of dynamic k-out-of-n configurations are also determined

Shape optimization as a tool to design biocatalytic microreactors

DEFF Research Database (Denmark)

Pereira Rosinha Grundtvig, Ines; Daugaard, Anders Egede; Woodley, John

2017-01-01

in this paper has as its main goal the design of a reactor by compensating for the limitations of the reaction system by modifying the reactor configuration. Random search was the optimization method chosen for transforming the initial reactor configuration to a more optimal one. The case study presented here...

Compact Ignition Tokamak conventional facilities optimization

International Nuclear Information System (INIS)

Commander, J.C.; Spang, N.W.

1987-01-01

A high-field ignition machine with liquid-nitrogen-cooled copper coils, designated the Compact Ignition Tokamak (CIT), is proposed for the next phase of the United States magnetically confined fusion program. A team of national laboratory, university, and industrial participants completed the conceptual design for the CIT machine, support systems and conventional facilities. Following conceptual design, optimization studies were conducted with the goal of improving machine performance, support systems design, and conventional facilities configuration. This paper deals primarily with the conceptual design configuration of the CIT conventional facilities, the changes that evolved during optimization studies, and the revised changes resulting from functional and operational requirements (F and ORs). The CIT conventional facilities conceptual design is based on two premises: (1) satisfaction of the F and ORs developed in the CIT building and utilities requirements document, and (2) the assumption that the CIT project will be sited at the Princeton Plasma Physics Laboratory (PPPL) in order that maximum utilization can be made of existing Tokamak Fusion Test Reactor (TFTR) buildings and utilities. The optimization studies required reevaluation of the F and ORs and a second look at TFTR buildings and utilities. Some of the high-cost-impact optimization studies are discussed, including the evaluation criteria for a change from the conceptual design baseline configuration. The revised conventional facilities configuration are described and the estimated cost impact is summarized

The effect of work shift configurations on emergency medical dispatch center response.

Science.gov (United States)

Montassier, Emmanuel; Labady, Julien; Andre, Antoine; Potel, Gilles; Berthier, Frederic; Jenvrin, Joel; Penverne, Yann

2015-01-01

It has been proved that emergency medical dispatch centers (EMDC) save lives by promoting an appropriate allocation of emergency medical service resources. Indeed, optimal dispatcher call duration is pivotal to reduce the time gap between the time a call is placed and the delivery of medical care. However, little is known about the impact of work shift configurations (i.e., work shift duration and work shift rotation throughout the day) and dispatcher call duration. Thus, the objective of our study was to assess the effect of work shift configurations on dispatcher call duration. During a 1-year study period, we analyzed the dispatcher call durations for medical and trauma calls during the 4 different work shift rotations (day, morning, evening, and night) and during the 10-hour work shift of each dispatcher in the EMDC of Nantes. We extracted dispatcher call durations from our advanced telephone system, configured with CC Pulse + (Genesys, Alcatel Lucent), and collected them in a custom designed database (Excel, Microsoft). Afterward, we analyzed these data using linear mixed effects models. During the study period, our EMDC received 408,077 calls. Globally, the mean dispatcher call duration was 107 ± 45 seconds. Based on multivariate linear mixed effects models, the dispatcher call duration was affected by night work shift and work shift duration greater than 8 hours, increasing it by about 10 ± 1 seconds and 4 ± 1 seconds, respectively (both p work shift rotation and duration, with longer durations seen over night shifts and shifts over 8 hours. While these differences are small and may not have clinical significance, they may have implications for EMDC efficiency.

Advanced commercial Tokamak optimization studies

International Nuclear Information System (INIS)

Whitley, R.H.; Berwald, D.H.; Gordon, J.D.

1985-01-01

Our recent studies have concentrated on developing optimal high beta (bean-shaped plasma) commercial tokamak configurations using TRW's Tokamak Reactor Systems Code (TRSC) with special emphasis on lower net electric power reactors that are more easily deployable. A wide range of issues were investigated in the search for the most economic configuration: fusion power, reactor size, wall load, magnet type, inboard blanket and shield thickness, plasma aspect ratio, and operational β value. The costs and configurations of both steady-state and pulsed reactors were also investigated. Optimal small and large reactor concepts were developed and compared by studying the cost of electricity from single units and from multiplexed units. Multiplexed units appear to have advantages because they share some plant equipment and have lower initial capital investment as compared to larger single units

Model-based evaluation of the short-circuited tripolar cuff configuration.

Science.gov (United States)

Andreasen, Lotte N S; Struijk, Johannes J

2006-05-01

Recordings of neural information for use as feedback in functional electrical stimulation are often contaminated with interfering signals from muscles and from stimulus pulses. The cuff electrode used for the neural recording can be optimized to improve the S/I ratio. In this work, we evaluate a model of both the nerve signal and the interfering signals recorded by a cuff, and subsequently use this model to study the signal to interference ratio of different cuff designs and to evaluate a recently introduced short-circuited tripolar cuff configuration. The results of the model showed good agreement with results from measurements in rabbits and confirmed the superior performance of the short-circuited tripolar configuration as compared with the traditionally used tripolar configuration.

Modeling and optimization of a concentrated solar supercritical CO2 power plant

Science.gov (United States)

Osorio, Julian D.

parameters and optimization of less efficient components. The parametric optimization is developed for a 1MW reference CSP system with CO2 as the working fluid. The component optimization, focused on the less efficient components, comprises some design modifications to the traditional component configuration for the recuperator, the hot thermal energy storage tank and the solar receiver. The proposed optimization alternatives include the heat exchanger's effectiveness enhancement by optimizing fins shapes, multi-tank thermal energy storage configurations for the hot thermal energy storage tank and the incorporation of a transparent insulation material into the solar receiver. Some of the optimizations are conducted in a generalized way, using dimensionless models to be applicable no only to the CSP but also to other thermal systems. This project is therefore an effort to improve the efficiency of power generation systems based on solar energy in order to make them competitive with conventional fossil fuel power generation devices. The results show that the parametric optimization leads the system to an efficiency of about 21% and a maximum power output close to 1.5 MW. The process efficiencies obtained in this work, of more than 21%, are relatively good for a solar-thermal conversion system and are also comparable with efficiencies of conversion of high performance PV panels. The thermal energy storage allows the system to operate for several hours after sunset. This operating time is approximately increased from 220 to 480 minutes after optimization. The hot and cold thermal energy storage also lessens the temperature fluctuations by providing smooth changes of temperatures at the turbines' and compressors' inlets. Additional improvements in the overall system efficiency are possible by optimizing the less efficient components. In particular, the fin's effectiveness can be improved in more than 5% after its shape is optimized, increments in the efficiency of the thermal

High-performance semiconductor optical preamplifier receiver at 10 Gb/s

DEFF Research Database (Denmark)

Mikkelsen, Benny; Jørgensen, Carsten Gudmann; Jensen, N.

1993-01-01

A semiconductor optical preamplifier receiver for bitrates of 10 Gb/s is described. The measured sensitivity is -28 dBm, with a polarization sensitivity of less than 0.5 dB. Using the same transmitter and receiver configuration but with a 980-nm pumped fiber amplifier instead of the semiconductor...... amplifier, the sensitivity is -34 dBm...

Implementing a Near-Optimal Optical Receiver for Inter-Planetary Communication

Data.gov (United States)

National Aeronautics and Space Administration — Proposal Objective: Interplanetary communications signals are inherently weak at the receiver. In fact, for a desired data rate the received optical pulses may...

Mate choice in the eye and ear of the beholder? Female multimodal sensory configuration influences her preferences.

Science.gov (United States)

Ronald, Kelly L; Fernández-Juricic, Esteban; Lucas, Jeffrey R

2018-05-16

A common assumption in sexual selection studies is that receivers decode signal information similarly. However, receivers may vary in how they rank signallers if signal perception varies with an individual's sensory configuration. Furthermore, receivers may vary in their weighting of different elements of multimodal signals based on their sensory configuration. This could lead to complex levels of selection on signalling traits. We tested whether multimodal sensory configuration could affect preferences for multimodal signals. We used brown-headed cowbird ( Molothrus ater ) females to examine how auditory sensitivity and auditory filters, which influence auditory spectral and temporal resolution, affect song preferences, and how visual spatial resolution and visual temporal resolution, which influence resolution of a moving visual signal, affect visual display preferences. Our results show that multimodal sensory configuration significantly affects preferences for male displays: females with better auditory temporal resolution preferred songs that were shorter, with lower Wiener entropy, and higher frequency; and females with better visual temporal resolution preferred males with less intense visual displays. Our findings provide new insights into mate-choice decisions and receiver signal processing. Furthermore, our results challenge a long-standing assumption in animal communication which can affect how we address honest signalling, assortative mating and sensory drive. © 2018 The Author(s).

A linear program for optimal configurable business processes deployment into cloud federation

NARCIS (Netherlands)

Rekik, M.; Boukadi, K.; Assy, N.; Gaaloul, W.; Ben-Abdallah, H.; Zhang, J.; Miller, J.A.; Xu, X.

2016-01-01

A configurable process model is a generic model from which an enterprise can derive and execute process variants that meet its specific needs and contexts. With the advent of cloud computing and its economic pay-per-use model, enterprises are increasingly outsourcing partially or totally their

SU-F-T-35: Optimization of Bladder and Rectal Doses Using a Multi-Lumen Intracavitary Applicator for Gynecological Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Laoui, S; Dietrich, S; Sehgal, V; Al-Ghazi, M [University of California, Irvine, Orange, CA (United States)

2016-06-15

Purpose: Radiation dose delivery for endometrial cancer using HDR techniques is limited by dose to bladder and rectum. A dosimetric study was performed using Varian Capri vaginal brachytherapy applicator to determine the optimal channel configuration which minimizes dose to bladder and rectum, while providing good target coverage. Methods: A total of 17 patients, 63 plans clinically delivered, and 252 simulated plans using Varian BrachyVision planning system were generated to investigate optimal channel configuration which results in minimum dose to bladder and rectum while providing adequate target coverage. The Capri applicator consists of 13 lumens arranged in two concentric rings, one central lumen and six lumens per ring. Manual dose shaping is invariably required to lower the dose to critical organs. Three-dimensional plans were simulated for 4 channel arrangements, all 13 channels, channel 12 o’clock (close to bladder) and 6 o’clock (close to rectum) deactivated, central channel deactivated, and central channel in addition to 12 o’clock and 6 o’clock deactivated. A relationship between V100, the volume that receives the prescribed dose, and the amount of curie-seconds required to deliver it, was established. Results: Using all 13 channels results in maximum dose to bladder and rectum. Deactivating central channel in addition to 12 o’clock and 6 o’clock resulted in minimizing bladder and rectum doses but compromised target coverage. The relationship between V100, the volume that receives the prescribed dose, and the curie seconds was found to be linear. Conclusion: Deactivating channels 12 o’clock and 6 o’clock was shown to be the optimal configuration leading to minimum dose to bladder and rectum without compromising target coverage. The linear relationship between V100 and the curie- seconds can be used as a verification parameter.

The Database Driven ATLAS Trigger Configuration System

CERN Document Server

Martyniuk, Alex; The ATLAS collaboration

2015-01-01

This contribution describes the trigger selection configuration system of the ATLAS low- and high-level trigger (HLT) and the upgrades it received in preparation for LHC Run 2. The ATLAS trigger configuration system is responsible for applying the physics selection parameters for the online data taking at both trigger levels and the proper connection of the trigger lines across those levels. Here the low-level trigger consists of the already existing central trigger (CT) and the new Level-1 Topological trigger (L1Topo), which has been added for Run 2. In detail the tasks of the configuration system during the online data taking are Application of the selection criteria, e.g. energy cuts, minimum multiplicities, trigger object correlation, at the three trigger components L1Topo, CT, and HLT On-the-fly, e.g. rate-dependent, generation and application of prescale factors to the CT and HLT to adjust the trigger rates to the data taking conditions, such as falling luminosity or rate spikes in the detector readout ...

Optimal back-to-front airplane boarding

Science.gov (United States)

Bachmat, Eitan; Khachaturov, Vassilii; Kuperman, Ran

2013-06-01

The problem of finding an optimal back-to-front airplane boarding policy is explored, using a mathematical model that is related to the 1+1 polynuclear growth model with concave boundary conditions and to causal sets in gravity. We study all airplane configurations and boarding group sizes. Optimal boarding policies for various airplane configurations are presented. Detailed calculations are provided along with simulations that support the main conclusions of the theory. We show that the effectiveness of back-to-front policies undergoes a phase transition when passing from lightly congested airplanes to heavily congested airplanes. The phase transition also affects the nature of the optimal or near-optimal policies. Under what we consider to be realistic conditions, optimal back-to-front policies lead to a modest 8-12% improvement in boarding time over random (no policy) boarding, using two boarding groups. Having more than two groups is not effective.

Optimal back-to-front airplane boarding.

Science.gov (United States)

Bachmat, Eitan; Khachaturov, Vassilii; Kuperman, Ran

2013-06-01

The problem of finding an optimal back-to-front airplane boarding policy is explored, using a mathematical model that is related to the 1+1 polynuclear growth model with concave boundary conditions and to causal sets in gravity. We study all airplane configurations and boarding group sizes. Optimal boarding policies for various airplane configurations are presented. Detailed calculations are provided along with simulations that support the main conclusions of the theory. We show that the effectiveness of back-to-front policies undergoes a phase transition when passing from lightly congested airplanes to heavily congested airplanes. The phase transition also affects the nature of the optimal or near-optimal policies. Under what we consider to be realistic conditions, optimal back-to-front policies lead to a modest 8-12% improvement in boarding time over random (no policy) boarding, using two boarding groups. Having more than two groups is not effective.

Tokamak configuration analysis with the method of toroidal multipoles

International Nuclear Information System (INIS)

Micozzi, P.; Alladio, F.; Crisanti, F.; Marinucci, M.; Tanga, A.

1989-01-01

In the study of tokamak machines able to sustain plasmas of thermonuclear interest (JIT, IGNITOR, NET, CIT, ET), there is a strong quest for engineering optimization of the circuital components close to the plasma. We have developed a semianalytical axisymmetric MHD equilibrium code based on the technique of the poloidal ψ flux function expansion in toroidal harmonic series. This code is able to optimize the necessary currents in the poloidal circuits in order to sustain a plasma of fixed shape (also x-point configuration), toroidal current and poloidal β. (author) 4 refs., 4 figs

Effect of geometrical optimization on the treatment volumes and the dose homogeneity of biplane interstitial brachytherapy implants

International Nuclear Information System (INIS)

Anacak, Yavuz; Esassolak, Mustafa; Aydin, Ayhan; Aras, Arif; Olacak, Ibrahim; Haydaroglu, Ayfer

1997-01-01

Background and purpose: The isodose distributions of HDR stepping source brachytherapy implants can be modified by changing dwell times and this procedure is called optimization. The purpose of this study is to evaluate the effect of geometrical optimization on the brachytherapy volumes and the dose homogeneity inside the implant and to compare them with non-optimized counterparts. Material and methods: A set of biplane breast implants consisting of 84 different configurations have been digitized by the planning computer and volumetric analysis was performed for both non-optimized and geometrically optimized implants. Treated length (T L ), treated volume (V 100 ), irradiated volume (V 50 ), overdose volume (V 200 ) and quality index (QI) have been calculated for every non-optimized implant and compared to its corresponding geometrically optimized implant having a similar configuration and covering the same target length. Results: The mean T L was 74.48% of the active length (A L ) for non-optimized implants and was 91.87% for optimized implants (P 50 /V 100 value was 2.71 for non-optimized implants and 2.65 for optimized implants (P 200 /V 100 value was 0.09 for non-optimized implants and 0.10 for optimized implants (P < 0.001). Conclusions: By performing geometrical optimization it is possible to implant shorter needles for a given tumour to adequately cover the target volume with the reference isodose and thus surgical damage is reduced. The amount of healthy tissues outside the target receiving considerable radiation is significantly reduced due to the decrease in irradiated volume. Dose homogeneity inside the implant is significantly improved. Although there is a slight increase of overdose volume inside the implant, this increase is considered to be negligible in clinical applications

Algorithm-enabled partial-angular-scan configurations for dual-energy CT.

Science.gov (United States)

Chen, Buxin; Zhang, Zheng; Xia, Dan; Sidky, Emil Y; Pan, Xiaochuan

2018-05-01

We seek to investigate an optimization-based one-step method for image reconstruction that explicitly compensates for nonlinear spectral response (i.e., the beam-hardening effect) in dual-energy CT, to investigate the feasibility of the one-step method for enabling two dual-energy partial-angular-scan configurations, referred to as the short- and half-scan configurations, on standard CT scanners without involving additional hardware, and to investigate the potential of the short- and half-scan configurations in reducing imaging dose and scan time in a single-kVp-switch full-scan configuration in which two full rotations are made for collection of dual-energy data. We use the one-step method to reconstruct images directly from dual-energy data through solving a nonconvex optimization program that specifies the images to be reconstructed in dual-energy CT. Dual-energy full-scan data are generated from numerical phantoms and collected from physical phantoms with the standard single-kVp-switch full-scan configuration, whereas dual-energy short- and half-scan data are extracted from the corresponding full-scan data. Besides visual inspection and profile-plot comparison, the reconstructed images are analyzed also in quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation. Following the performance of a computer-simulation study to verify that the one-step method can reconstruct numerically accurately basis and monochromatic images of numerical phantoms, we reconstruct basis and monochromatic images by using the one-step method from real data of physical phantoms collected with the full-, short-, and half-scan configurations. Subjective inspection based upon visualization and profile-plot comparison reveals that monochromatic images, which are used often in practical applications, reconstructed from the full-, short-, and half-scan data are largely visually comparable except for some

Bi-2223 HTS winding in toroidal configuration for SMES coil

International Nuclear Information System (INIS)

Kondratowicz-Kucewicz, B; Kozak, S; Kozak, J; Wojtasiewicz, G; Majka, M; Janowski, T

2010-01-01

Energy can be stored in the magnetic field of a coil. Superconducting Magnetic Energy Storage (SMES) is very promising as a power storage system for load levelling or power stabilizer. However, the strong electromagnetic force caused by high magnetic field and large coil current is a problem in SMES systems. A toroidal configuration would have a much less extensive external magnetic field and electromagnetic forces in winding. The paper describes the design of HTS winding for SMES coil in modular toroid configuration consist of seven Bi-2223 double-pancakes as well as numerical analysis of SMES magnet model using FLUX 3D package. As the results of analysis the paper presents the optimal coil configuration and the parameters such as radius of toroidal magnet, energy stored in magnet and magnetic field distribution.

Impact of Blanket Configuration on the Design of a Fusion-Driven Transmutation Reactor

Directory of Open Access Journals (Sweden)

Bong Guen Hong

2018-02-01

Full Text Available A configuration of a fusion-driven transmutation reactor with a low aspect ratio tokamak-type neutron source was determined in a self-consistent manner by using coupled analysis of tokamak systems and neutron transport. We investigated the impact of blanket configuration on the characteristics of a fusion-driven transmutation reactor. It was shown that by merging the TRU burning blanket and tritium breeding blanket, which uses PbLi as the tritium breeding material and as coolant, effective transmutation is possible. The TRU transmutation capability can be improved with a reduced blanket thickness, and fast fluence at the first wall can be reduced.  Article History: Received: July 10th 2017; Received: Dec 17th 2017; Accepted: February 2nd 2018; Available online How to Cite This Article: Hong, B.G. (2018 Impact of Blanket Configuration on the Design of a Fusion-Driven Transmutation Reactor. International Journal of Renewable Energy Development, 7(1, 65-70. https://doi.org/10.14710/ijred.7.1.65-70

Integrating configuration workflows with project management system

International Nuclear Information System (INIS)

Nilsen, Dimitri; Weber, Pavel

2014-01-01

The complexity of the heterogeneous computing resources, services and recurring infrastructure changes at the GridKa WLCG Tier-1 computing center require a structured approach to configuration management and optimization of interplay between functional components of the whole system. A set of tools deployed at GridKa, including Puppet, Redmine, Foreman, SVN and Icinga, provides the administrative environment giving the possibility to define and develop configuration workflows, reduce the administrative effort and improve sustainable operation of the whole computing center. In this presentation we discuss the developed configuration scenarios implemented at GridKa, which we use for host installation, service deployment, change management procedures, service retirement etc. The integration of Puppet with a project management tool like Redmine provides us with the opportunity to track problem issues, organize tasks and automate these workflows. The interaction between Puppet and Redmine results in automatic updates of the issues related to the executed workflow performed by different system components. The extensive configuration workflows require collaboration and interaction between different departments like network, security, production etc. at GridKa. Redmine plugins developed at GridKa and integrated in its administrative environment provide an effective way of collaboration within the GridKa team. We present the structural overview of the software components, their connections, communication protocols and show a few working examples of the workflows and their automation.

Use of Monte Carlo Simulations to Determine Optimal Carbapenem Dosing in Critically Ill Patients Receiving Prolonged Intermittent Renal Replacement Therapy.

Science.gov (United States)

Lewis, Susan J; Kays, Michael B; Mueller, Bruce A

2016-10-01

Pharmacokinetic/pharmacodynamic analyses with Monte Carlo simulations (MCSs) can be used to integrate prior information on model parameters into a new renal replacement therapy (RRT) to develop optimal drug dosing when pharmacokinetic trials are not feasible. This study used MCSs to determine initial doripenem, imipenem, meropenem, and ertapenem dosing regimens for critically ill patients receiving prolonged intermittent RRT (PIRRT). Published body weights and pharmacokinetic parameter estimates (nonrenal clearance, free fraction, volume of distribution, extraction coefficients) with variability were used to develop a pharmacokinetic model. MCS of 5000 patients evaluated multiple regimens in 4 different PIRRT effluent/duration combinations (4 L/h × 10 hours or 5 L/h × 8 hours in hemodialysis or hemofiltration) occurring at the beginning or 14-16 hours after drug infusion. The probability of target attainment (PTA) was calculated using ≥40% free serum concentrations above 4 times the minimum inhibitory concentration (MIC) for the first 48 hours. Optimal doses were defined as the smallest daily dose achieving ≥90% PTA in all PIRRT combinations. At the MIC of 2 mg/L for Pseudomonas aeruginosa, optimal doses were doripenem 750 mg every 8 hours, imipenem 1 g every 8 hours or 750 mg every 6 hours, and meropenem 1 g every 12 hours or 1 g pre- and post-PIRRT. Ertapenem 500 mg followed by 500 mg post-PIRRT was optimal at the MIC of 1 mg/L for Streptococcus pneumoniae. Incorporating data from critically ill patients receiving RRT into MCS resulted in markedly different carbapenem dosing regimens in PIRRT from those recommended for conventional RRTs because of the unique drug clearance characteristics of PIRRT. These results warrant clinical validation. © 2016, The American College of Clinical Pharmacology.

Overview of homogeneous versus heterogeneous core configuration trade-off studies

International Nuclear Information System (INIS)

Chang, Y.I.

1982-01-01

The most significant development in core design trend in the U.S. LMFBR program has been the increased attention given to the heterogeneous core design concept. In recent years, numerous core configuration trade-off studies have been carried out to quantify advantages and disadvantages of the heterogeneous concept relative to the homogeneous concept, and a consensus is emerging among the U.S. core designers. It appears that the technical and economic performance differences between homogeneous and heterogeneous core designs are very small; however, the heterogeneous concept provides a definite safety/licensing advantage. he technical and economic performance comparison between homogeneous and heterogeneous core configurations is difficult to quantify. In fact, in most cases, the perceived advantages and/or disadvantages are dictated by the consistency in the comparison (optimized for one concept versus non-optimized for the other, etc.) rather than by any inherent differences. Some of the technical and economic issues relevant to the homogeneous versus heterogeneous comparison are summarized

Overview of homogeneous versus heterogeneous core configuration trade-off studies

Energy Technology Data Exchange (ETDEWEB)

Chang, Y I [Applied Physics Division, Argonne National Laboratory, Argonne, IL (United States)

1982-01-01

The most significant development in core design trend in the U.S. LMFBR program has been the increased attention given to the heterogeneous core design concept. In recent years, numerous core configuration trade-off studies have been carried out to quantify advantages and disadvantages of the heterogeneous concept relative to the homogeneous concept, and a consensus is emerging among the U.S. core designers. It appears that the technical and economic performance differences between homogeneous and heterogeneous core designs are very small; however, the heterogeneous concept provides a definite safety/licensing advantage. he technical and economic performance comparison between homogeneous and heterogeneous core configurations is difficult to quantify. In fact, in most cases, the perceived advantages and/or disadvantages are dictated by the consistency in the comparison (optimized for one concept versus non-optimized for the other, etc.) rather than by any inherent differences. Some of the technical and economic issues relevant to the homogeneous versus heterogeneous comparison are summarized.

Conceptualizing Embedded Configuration

DEFF Research Database (Denmark)

Oddsson, Gudmundur Valur; Hvam, Lars; Lysgaard, Ole

2006-01-01

and services. The general idea can be named embedded configuration. In this article we intend to conceptualize embedded configuration, what it is and is not. The difference between embedded configuration, sales configuration and embedded software is explained. We will look at what is needed to make embedded...... configuration systems. That will include requirements to product modelling techniques. An example with consumer electronics will illuminate the elements of embedded configuration in settings that most can relate to. The question of where embedded configuration would be relevant is discussed, and the current...

Thermal Model of a Dish Stirling Cavity-Receiver

Directory of Open Access Journals (Sweden)

Rubén Gil

2015-01-01

Full Text Available This paper presents a thermal model for a dish Stirling cavity based on the finite differences method. This model is a theoretical tool to optimize the cavity in terms of thermal efficiency. One of the main outcomes of this work is the evaluation of radiative exchange using the radiosity method; for that purpose, the view factors of all surfaces involved have been accurately calculated. Moreover, this model enables the variation of the cavity and receiver dimensions and the materials to determine the optimal cavity design. The tool has been used to study the cavity optimization regarding geometry parameters and material properties. Receiver absorptivity has been identified as the most influential property of the materials. The optimal aperture height depends on the minimum focal space.

Optimizing Teleportation Cost in Distributed Quantum Circuits

Science.gov (United States)

Zomorodi-Moghadam, Mariam; Houshmand, Mahboobeh; Houshmand, Monireh

2018-03-01

The presented work provides a procedure for optimizing the communication cost of a distributed quantum circuit (DQC) in terms of the number of qubit teleportations. Because of technology limitations which do not allow large quantum computers to work as a single processing element, distributed quantum computation is an appropriate solution to overcome this difficulty. Previous studies have applied ad-hoc solutions to distribute a quantum system for special cases and applications. In this study, a general approach is proposed to optimize the number of teleportations for a DQC consisting of two spatially separated and long-distance quantum subsystems. To this end, different configurations of locations for executing gates whose qubits are in distinct subsystems are considered and for each of these configurations, the proposed algorithm is run to find the minimum number of required teleportations. Finally, the configuration which leads to the minimum number of teleportations is reported. The proposed method can be used as an automated procedure to find the configuration with the optimal communication cost for the DQC. This cost can be used as a basic measure of the communication cost for future works in the distributed quantum circuits.

Ramjet Nozzle Analysis for Transport Aircraft Configuration for Sustained Hypersonic Flight

Directory of Open Access Journals (Sweden)

Raman Baidya

2018-04-01

Full Text Available For the past several decades, research dealing with hypersonic flight regimes has been restricted mainly to military applications. Hypersonic transportation could be a possible and affordable solution to travel in the medium term and there is renewed interest from several private organisations for commercial exploitation in this direction. Various combined cycle propulsion configurations have been proposed and the present paper deals with implications for the nozzle component of a ramjet configuration as part of one such combined cycle propulsion configuration. An investigation was undertaken for a method of turbine-based propulsion which enables the hypersonic vehicle to take off under its own power and propel the aircraft under different mission profiles into ramjet operational Mach regimes. The present study details an optimal method of ramjet exhaust expansion to produce sufficient thrust to propel the vehicle into altitudes and Mach regimes where scramjet operation can be initiated. This aspect includes a Computational Fluid Dynamics (CFD-based geometric study to determine the optimal configuration to provide the best thrust values. The CFD parametric analysis investigated three candidate nozzles and indicated that the dual bell nozzle design produced the highest thrust values when compared to other nozzle geometries. The altitude adaptation study also validated the effectiveness of the nozzle thrust at various altitudes without compromising its thrust-producing capabilities. Computational data were validated against published experimental data, which indicated that the computed values correlated well with the experimental data.

Monte Carlo simulations as a part of the configuration for neutron instruments

DEFF Research Database (Denmark)

Andersen, P.; Lefmann, K.; Kuhn, L.T.

2004-01-01

We demonstrate the use of simulations in the process of determiningthe optimal instrument setup by virtual experiments usingthe simulation package McStas. The focus of the analysis is the optimization of the multi-blade analyzer present at the RITA-II spectrometer at PSI for a test experiment...... that in general instrument simulations are approaching a state where they can assist users in selectingthe optimal configuration and possibly demonstrate the feasibility of their experiments prior to allocated beamtime. (C) 2004 Elsevier B.V. All rights reserved....

Multi-resolution analysis using integrated microscopic configuration with local patterns for benign-malignant mass classification

Science.gov (United States)

Rabidas, Rinku; Midya, Abhishek; Chakraborty, Jayasree; Sadhu, Anup; Arif, Wasim

2018-02-01

In this paper, Curvelet based local attributes, Curvelet-Local configuration pattern (C-LCP), is introduced for the characterization of mammographic masses as benign or malignant. Amid different anomalies such as micro- calcification, bilateral asymmetry, architectural distortion, and masses, the reason for targeting the mass lesions is due to their variation in shape, size, and margin which makes the diagnosis a challenging task. Being efficient in classification, multi-resolution property of the Curvelet transform is exploited and local information is extracted from the coefficients of each subband using Local configuration pattern (LCP). The microscopic measures in concatenation with the local textural information provide more discriminating capability than individual. The measures embody the magnitude information along with the pixel-wise relationships among the neighboring pixels. The performance analysis is conducted with 200 mammograms of the DDSM database containing 100 mass cases of each benign and malignant. The optimal set of features is acquired via stepwise logistic regression method and the classification is carried out with Fisher linear discriminant analysis. The best area under the receiver operating characteristic curve and accuracy of 0.95 and 87.55% are achieved with the proposed method, which is further compared with some of the state-of-the-art competing methods.

Study on Resource Configuration on Cloud Manufacturing

Directory of Open Access Journals (Sweden)

Yanlong Cao

2015-01-01

Full Text Available The purpose of manufacturing is to realize the requirement of customer. In manufacturing process of cloud system, there exist a lot of resource services which have similar functional characteristics to realize the requirement. It makes the manufacturing process more diverse. To develop the quality and reduce cost, a resource configuration model on cloud-manufacturing platform is put forward in this paper. According to the generalized six-point location principle, a growth design from the requirement of customers to entities with geometric constraints is proposed. By the requirement growing up to product, a configuration process is used to match the entities with the instances which the resources in the database could supply. Different from most existing studies, this paper studies the tolerance design with multiple candidate resource suppliers on cloud manufacturing to make the market play a two-level game considering the benefit of customers and the profit of resources to give an optimal result. A numerical case study is used to illustrate the proposed model and configuration process. The performance and advantage of the proposed method are discussed at the end.

A Configurable Surface-Electrode Ion Trap Design for Quantum Information Processing

International Nuclear Information System (INIS)

Liu Wei; Chen Shu-Ming; Chen Ping-Xing; Wu Wei

2013-01-01

We propose a configurable surface-electrode ion trap design to alleviate the poor reusability of the existing traps. It can architecturally and electrically support 5 mainstream modes by design reuse, thus enhancing the trap reusability and reducing the experiment setup overhead. We also develop a corresponding simulation suite which can optimize trap geometries and calculate trap parameters to control the trapped ion's classic motion. According to our analytical and simulated results, the configurable design can serve as a unified platform for basic research of large-scale quantum information processing

Plug-and-play monitoring and performance optimization for industrial automation processes

CERN Document Server

Luo, Hao

2017-01-01

Dr.-Ing. Hao Luo demonstrates the developments of advanced plug-and-play (PnP) process monitoring and control systems for industrial automation processes. With aid of the so-called Youla parameterization, a novel PnP process monitoring and control architecture (PnP-PMCA) with modularized components is proposed. To validate the developments, a case study on an industrial rolling mill benchmark is performed, and the real-time implementation on a laboratory brushless DC motor is presented. Contents PnP Process Monitoring and Control Architecture Real-Time Configuration Techniques for PnP Process Monitoring Real-Time Configuration Techniques for PnP Performance Optimization Benchmark Study and Real-Time Implementation Target Groups Researchers and students of Automation and Control Engineering Practitioners in the area of Industrial and Production Engineering The Author Hao Luo received the Ph.D. degree at the Institute for Automatic Control and Complex Systems (AKS) at the University of Duisburg-Essen, Germany, ...

Dose optimization in simulated permanent interstitial implant of prostate brachytherapy

International Nuclear Information System (INIS)

Faria, Fernando Pereira de

2006-01-01

Any treatment of cancer that uses some modality of radiotherapy is planned before being executed. In general the goal in radiotherapy is to irradiate the target to be treated minimizing the incidence of radiation in healthy surrounding tissues. The planning differ among themselves according to the modality of radiotherapy, the type of cancer and where it is located. This work approaches the problem of dose optimization for the planning of prostate cancer treatment through the modality of low dose-rate brachytherapy with Iodine 125 or Palladium 103 seeds. An algorithm for dose calculation and optimization was constructed to find the seeds configuration that better fits the relevant clinical criteria such as as the tolerated dose by the urethra and rectum and the desired dose for prostate. The algorithm automatically finds this configuration from the prostate geometry established in two or three dimensions by using images of ultrasound, magnetic resonance or tomography and from the establishment of minimum restrictions to the positions of the seeds in the prostate and needles in a template. Six patterns of seeds distribution based on clinical criteria were suggested and tested in this work. Each one of these patterns generated a space of possible seeds configurations for the prostate tested by the dose calculation and optimization algorithm. The configurations that satisfied the clinical criteria were submitted to a test according to an optimization function suggested in this work. The configuration that produced maximum value for this function was considered the optimized one. (author)

Optimization of foam-filled bitubal structures for crashworthiness criteria

International Nuclear Information System (INIS)

Zhang, Yong; Sun, Guangyong; Li, Guangyao; Luo, Zhen; Li, Qing

2012-01-01

Highlights: ► The paper aims to optimize foam-filled bitubal squared column for crashworthiness. ► It explores different formulations and configurations of design. ► The optimal foam-filled bitubal column is better than foam-filled monotubal column. ► The optimal foam-filled bitubal column is better than empty bitubal column. -- Abstract: Thin-walled structures have been widely used as key components in automobile and aerospace industry to improve the crashworthiness and safety of vehicles while maintaining overall light-weight. This paper aims to explore the design issue of thin-walled bitubal column structures filled with aluminum foam. As a relatively new filler material, aluminum foam can increase crashworthiness without sacrificing too much weight. To optimize crashworthiness of the foam-filled bitubal square column, the Kriging meta-modeling technique is adopted herein to formulate the objective and constraint functions. The genetic algorithm (GA) and Non-dominated Sorting Genetic Algorithm II (NSGA II) are used to seek the optimal solutions to the single and multiobjective optimization problems, respectively. To compare with other thin-walled configurations, the design optimization is also conducted for empty bitubal column and foam-filled monotubal column. The results demonstrate that the foam-filled bitubal configuration has more room to enhance the crashworthiness and can be an efficient energy absorber.

Combined effects of channel curvature and rotor configuration on the performance of two-stage viscous micropumps

Energy Technology Data Exchange (ETDEWEB)

Kang, Dong Jin [Yeungnam University, Gyeongsan (Korea, Republic of)

2017-06-15

The combined effects of channel curvature and rotor configuration on the performance of two-stage viscous micropumps were studied numerically. The Navier-Stokes equations were simulated to investigate the performance of two-stage micropumps. The performance of two-stage micropumps was studied in terms of the dimensionless mass flow rate and dimensionless driving power. Four different rotor configurations were designed by changing placement of two rotors inside a microchannel: Two aligned and two staggered configurations. The aligned rotor configuration of type 1 is to place the two rotors along the convex wall, while type 2 is to place them along the concave wall. Numerical results show that the rotor configuration plays a significant role in the performance of two-stage micropumps. The chan-nel curvature acts in a different way according to the rotor configuration. The mass flow rate of aligned rotor configuration of type 1 is greatly improved by the channel curvature, while it diminishes the mass flow rate of type 2. The maximum mass flow rate for the aligned rotor configuration of type 1 is obtained when the two rotors are placed at the junction of the circular and straight sections of the channel. The performance of staggered configurations is negligibly affected by the channel curvature. This characteristics is found due to rotation direction of the rotors. As the two rotors rotate in the opposite direction for the staggered configurations, the flow characteristics in the circular section is little affected by the channel curvature. The circumferential distance between the two rotors can be optimized in terms of the mass flow rate. The optimal value of the circumferential distance is about L = 1.4 for the staggered rotor configurations, and it is almost independent of the channel curvature. As the channel height increases, the circumferential distance becomes less significant for the staggered rotor configurations while it becomes significant for the aligned

TEM-turbulence in stellarators and its optimization

Science.gov (United States)

Proll, Josefine H. E.; Helander, Per; Lazerson, Samuel; Mynick, Harry; Xanthopoulos, Pavlos

2014-10-01

Quasi-isodynamic stellarators, which are especially optimized for neoclassical transport, have been shown to be resilient towards trapped-electrons modes (TEMs) in large regions of parameter space. In these configurations, all particles have average ``good curvature.'' It was shown analytically that, thanks to this property, particles that bounce faster than the mode in question draw energy from it near marginal stability, so that the ordinary density-gradient-driven TEM has to be stable in the electrostatic and collisionless limit.This has been confirmed in linear flux-tube simulations that were performed with the GENE code. Several magnetic field configurations were compared and it was found that the growth rates of the TEMs drop with increasing degree of quasi-isodynamicity. These findings can be used to optimize stellarators with respect to TEM turbulence by reducing the fraction of trapped particles with bounce averaged ``bad curvature.'' An appropriate proxy function has therefore been designed to be implemented in STELLOPT, a stellarator optimization tool that can now be used to further explore the configuration space of neoclassically optimized stellarators with the aim to extract designs with improved turbulent transport. This work was facilitated by the Max-Planck/Princeton Center for Plasma Physics.

A multi-institutional Stellarator Configuration Study

Science.gov (United States)

Gates, David

2017-10-01

A multi-institutional study aimed at mapping the space of quasi-axisymmetric stellarators has begun. The goal is to gain improved understanding of the dependence of important physics and engineering parameters (e.g. bootstrap current, stability, coil complexity, etc.) on plasma shape (average elongation, aspect ratio, number of periods). In addition, the stellarator optimization code STELLOPT will be upgraded with new capabilities such as improved coil design algorithms such as COILOPT + + and REGCOIL, divertor optimization options, equilibria with islands using the SPEC code, and improved bootstrap current calculations with the SFINCS code. An effort is underway to develop metrics for divertor optimization. STELLOPT has also had numerous improvements to numerical algorithms and parallelization capabilities. Simultaneously, we also are pursuing the optimization of turbulent transport according to the method of proxy functions. Progress made to date includes an elongation scan on quasi-axisymmetric equilibria and an initial comparison between the SFINCS code and the BOOTSJ calculation of bootstrap current currently available in STELLOPT. Further progress on shape scans and subsequent physics analysis will be reported. The status of the STELLOPT upgrades will be described. The eventual goal of this exercise is to identify attractive configurations for future US experimental facilities.. This work is supported by US DoE Contract Number DE-AC02-09CH11466.

Coupled Low-thrust Trajectory and System Optimization via Multi-Objective Hybrid Optimal Control

Science.gov (United States)

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.

Software configuration management

International Nuclear Information System (INIS)

Arribas Peces, E.; Martin Faraldo, P.

1993-01-01

Software Configuration Management is directed towards identifying system configuration at specific points of its life cycle, so as to control changes to the configuration and to maintain the integrity and traceability of the configuration throughout its life. SCM functions and tasks are presented in the paper

Optimal configuration of an integrated power and transport system

DEFF Research Database (Denmark)

Juul, Nina; Meibom, Peter

2011-01-01

optimal investments in both power plants and vehicle technologies is presented in this article. The model includes the interactions between the power system and the transport system including the competition between flexibility measures such as hydrogen storage in combination with electrolysis, heat...... storage in combination with heat pumps and heat boilers, and plug-in electric vehicles....

Optimization of membrane stack configuration for efficient hydrogen production in microbial reverse-electrodialysis electrolysis cells coupled with thermolytic solutions

KAUST Repository

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.

Modelling, Synthesis, and Configuration of Networks-on-Chips

DEFF Research Database (Denmark)

Stuart, Matthias Bo

This thesis presents three contributions in two different areas of network-on-chip and system-on-chip research: Application modelling and identifying and solving different optimization problems related to two specific network-on-chip architectures. The contribution related to application modelling...... is an analytical method for deriving the worst-case traffic pattern caused by an application and the cache-coherence protocol in a cache-coherent shared-memory system. The contributions related to network-on-chip optimization problems consist of two parts: The development and evaluation of six heuristics...... for solving the network synthesis problem in the MANGO network-on-chip, and the identification and formalization of the ReNoC configuration problem together with three heuristics for solving it....

Business cases for product configuration systems

DEFF Research Database (Denmark)

Shafiee, Sara; Kristjansdottir, Katrin; Hvam, Lars

In the recent years, product configuration systems (PCSs) have received greater attention from industries providing customized products as a response to increased demand to fulfil diverse customers’ needs for customized products. Before developing a PCS, a well-established business case has...... to be made in order to secure the success and delivery of the project as it will increase the commitment from the business side. This paper presents a framework for supporting the development of business cases for PCSs and discusses the experiences from multiple case studies benefiting from the suggested...

Injection and temporary capture of a charged particle beam in an open magnetic configuration. Optimization of the configuration. Case of cylindrical symmetry: A mirror machine; Etude de l'injection et de la capture temporaire d'un faisceau de particules chargees dans une configuration magnetique ouverte. Optimisation de la configuration. Cas de la symetrie de revolution: Machine a miroirs

Energy Technology Data Exchange (ETDEWEB)

Capdequi-Peyranere, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1966-12-01

A study has been made of a new method of transverse injection of charged particles into a magnetic mirror configuration. This injection scheme permits the penetration and temporary capture by non-adiabatic effect of a particle beam of approximately 1 cm{sup 2} cross-section. A theoretical study of the injection and capture is made in the approximation that space charge is negligible. The original programs for IBM 7094 computer calculations are described; these programs were used to obtain an optimization of the configuration. The results of a statistical numerical study of the optimum configuration are then given. This study indicates that, if the energy of the particles of the beam is about 1 per cent greater than a minimum penetration energy, the entire beam can be captured with an average capture length of 100 meters (50 reflections between the two mirrors). If the energy is about 4 per cent greater than the minimum penetration energy, the capture length is reduced to 40 meters. We have studied the distribution of energy transverse and longitudinal with the magnetic field for the population of captured particles. For the cases of injected molecular hydrogen ions or heavy CH{sub 4}{sup +} ions, a study is made of the capture time of protons resulting from the dissociation of the ions by collisions with the neutral gas. Finally, we describe a model experiment using electrons designed to provide an experimental verification of the capture of the primary beam. (author) [French] On etudie un nouveau schema d'injection transversale de particules chargees dans une configuration magnetique a miroirs. Ce mode d'injection permet la penetration et la capture temporaire par effet non adiabatique d'un faisceau de particules presentant une section de l'ordre de 1 cm{sup 2}. Une etude theorique du probleme de l'injection et de la capture est faite en supposant la charge d'espace negligeable. On decrit des programmes originaux de calcul sur ordinateur IBM 7094 permettant l

Experimental optimization of exposure index and quality of service in WLAN networks

International Nuclear Information System (INIS)

Plets, David; Vermeeren, Gunter; Poorter, Eli De; Moerman, Ingrid; Martens, Luc; Joseph, Wout; Goudos, Sotirios K.

2017-01-01

This paper presents the first real-life optimization of the Exposure Index (EI). A genetic optimization algorithm is developed and applied to three real-life Wireless Local Area Network scenarios in an experimental test-bed. The optimization accounts for down-link, uplink and uplink of other users, for realistic duty cycles, and ensures a sufficient Quality of Service to all users. EI reductions up to 97.5% compared to a reference configuration can be achieved in a down-link-only scenario, in combination with an improved Quality of Service. Due to the dominance of uplink exposure and the lack of WiFi power control, no optimizations are possible in scenarios that also consider uplink traffic. However, future deployments that do implement WiFi power control can be successfully optimized, with EI reductions up to 86% compared to a reference configuration and an EI that is 278 times lower than optimized configurations under the absence of power control. (authors)

Mark 4A DSN receiver-exciter and transmitter subsystems

Science.gov (United States)

Wick, M. R.

1986-01-01

The present configuration of the Mark 4A DSN Receiver-Exciter and Transmitter Subsystems is described. Functional requirements and key characteristics are given to show the differences in the capabilities required by the Networks Consolidation task for combined High Earth Orbiter and Deep Space Network tracking support.

An extension of the receiver operating characteristic curve and AUC-optimal classification.

Science.gov (United States)

Takenouchi, Takashi; Komori, Osamu; Eguchi, Shinto

2012-10-01

While most proposed methods for solving classification problems focus on minimization of the classification error rate, we are interested in the receiver operating characteristic (ROC) curve, which provides more information about classification performance than the error rate does. The area under the ROC curve (AUC) is a natural measure for overall assessment of a classifier based on the ROC curve. We discuss a class of concave functions for AUC maximization in which a boosting-type algorithm including RankBoost is considered, and the Bayesian risk consistency and the lower bound of the optimum function are discussed. A procedure derived by maximizing a specific optimum function has high robustness, based on gross error sensitivity. Additionally, we focus on the partial AUC, which is the partial area under the ROC curve. For example, in medical screening, a high true-positive rate to the fixed lower false-positive rate is preferable and thus the partial AUC corresponding to lower false-positive rates is much more important than the remaining AUC. We extend the class of concave optimum functions for partial AUC optimality with the boosting algorithm. We investigated the validity of the proposed method through several experiments with data sets in the UCI repository.

Reactor assessments of advanced bumpy torus configurations

International Nuclear Information System (INIS)

Uckan, N.A.; Owen, L.W.; Spong, D.A.; Miller, R.L.; Ard, W.B.; Pipkins, J.F.; Schmitt, R.J.

1984-02-01

Recently, several innovative approaches were introduced for enhancing the performance of the basic ELMO Bumpy Torus (EBT) concept and for improving its reactor potential. These include planar racetrack and square geometries, Andreoletti coil systems, and bumpy torus-stellarator hybrids (which include twisted racetrack and helical axis stellarator - snakey torus). Preliminary evaluations of reactor implications of each approach have been carried out based on magnetics (vacuum) calculations, transport and scaling relationships, and stability properties deduced from provisional configurations that implement the approach but are not necessarily optimized. Further optimization is needed in all cases to evaluate the full potential of each approach. Results of these studies indicate favorable reactor projections with a significant reduction in reactor physical size as compared to conventional EBT reactor designs carried out in the past

Comparative analysis of imaging configurations and objectives for Fourier microscopy.

Science.gov (United States)

Kurvits, Jonathan A; Jiang, Mingming; Zia, Rashid

2015-11-01

Fourier microscopy is becoming an increasingly important tool for the analysis of optical nanostructures and quantum emitters. However, achieving quantitative Fourier space measurements requires a thorough understanding of the impact of aberrations introduced by optical microscopes that have been optimized for conventional real-space imaging. Here we present a detailed framework for analyzing the performance of microscope objectives for several common Fourier imaging configurations. To this end, we model objectives from Nikon, Olympus, and Zeiss using parameters that were inferred from patent literature and confirmed, where possible, by physical disassembly. We then examine the aberrations most relevant to Fourier microscopy, including the alignment tolerances of apodization factors for different objective classes, the effect of magnification on the modulation transfer function, and vignetting-induced reductions of the effective numerical aperture for wide-field measurements. Based on this analysis, we identify an optimal objective class and imaging configuration for Fourier microscopy. In addition, the Zemax files for the objectives and setups used in this analysis have been made publicly available as a resource for future studies.

Reducing Turbulent Transport in Toroidal Configurations via Shaping

International Nuclear Information System (INIS)

Mynick, H.E.; Pomphrey, N.; Xanthopoulos, P.

2011-01-01

Recent progress in reducing turbulent transport in stellarators and tokamaks by 3D shaping using a stellarator optimization code in conjunction with a gyrokinetic code is presented. The original applications of the method focussed on ion temperature gradient transport in a quasi-axisymmetric stellarator design. Here, an examination of both other turbulence channels and other starting configurations is initiated. It is found that the designs evolved for transport from ion temperature gradient turbulence also display reduced transport from other transport channels whose modes are also stabilized by improved curvature, such as electron temperature gradient and ballooning modes. The optimizer is also applied to evolving from a tokamak, finding appreciable turbulence reduction for these devices as well. From these studies, improved understanding is obtained of why the deformations found by the optimizer are beneficial, and these deformations are related to earlier theoretical work in both stellarators and tokamaks.

Configuration Management

International Nuclear Information System (INIS)

Morcos, A.; Taylor, H. S.

1989-01-01

This paper will briefly discuss the reason for and content of configuration management both for new plants and, when adapted, for older plants. It will then address three types of activities a utility may undertake as part of a nuclear CAM program and with which Sargent and Leyden has been actively involved. The first activity is a methodology for preparing design-basis documentation. The second is the identification of essential data required to be kept by the utility in support of the operation of a nuclear plant. The third activity is a computerized classification system of plant components, allowing ready identification of plant functional and physical characteristics. Plant configuration documentation describes plant components, the ways they arranged to interact, and the ways they are enabled to interact. Configuration management, on the other hand, is more than the control of such documentation. It is a dynamic process for ensuring that a plant configuration meets all relevant requirements for safety and economy, even while the configuration changes and even while the requirements change. Configuration management for a nuclear plant is so complex that it must be implemented in phases and modules. It takes advantage of and integrates existing programs. Managing complexity and streamlining the change process become important additional objectives of configuration management. The example activities fulfill essential goals of an overall CAM program: definition of design baseline, definition of essential plant data, and classification of plant components

The impact of optimize solar radiation received on the levels and energy disposal of levels on architectural design result by using computer simulation

Energy Technology Data Exchange (ETDEWEB)

Rezaei, Davood; Farajzadeh Khosroshahi, Samaneh; Sadegh Falahat, Mohammad [Zanjan University (Iran, Islamic Republic of)], email: d_rezaei@znu.ac.ir, email: ronas_66@yahoo.com, email: Safalahat@yahoo.com

2011-07-01

In order to minimize the energy consumption of a building it is important to achieve optimum solar energy. The aim of this paper is to introduce the use of computer modeling in the early stages of design to optimize solar radiation received and energy disposal in an architectural design. Computer modeling was performed on 2 different projects located in Los Angeles, USA, using ECOTECT software. Changes were made to the designs following analysis of the modeling results and a subsequent analysis was carried out on the optimized designs. Results showed that the computer simulation allows the designer to set the analysis criteria and improve the energy performance of a building before it is constructed; moreover, it can be used for a wide range of optimization levels. This study pointed out that computer simulation should be performed in the design stage to optimize a building's energy performance.

Studying the Issues in Laser Joining of Lightweight Materials in a Coach-Peel Joint Configuration

Science.gov (United States)

Yang, Guang

In the automotive industry, aluminum alloys have been widely used and partially replaced the conventional steel structures in order to decrease the weight of a car and improve its fuel efficiency. This Thesis focuses on the development of laser joining of light-weight materials, such as aluminum alloys and high-strength galvanized steels. Among different joint types, the coach-peel configuration is of a specific design that requires a heat source capable of heating up a large surface area of the joint. Coach-peel joints applied on the visible exterior of a car require a smooth transition from the weld surface to the panel surface and low surface roughness without any need for post-processing. Although these joints are used as non-load-bearing components, a desirable strength of the weld is also needed. A fusion-brazing process using a dual-beam laser allows the automotive components such as the roof and side member panels to be joined in a coach-peel configuration with a high surface quality as well as an acceptable strength of the weld. To improve the weld surface quality, processing parameters such as laser beam configuration, laser-wire position, and shielding gas parameters were optimized for joining of aluminum alloy to aluminum alloy. Laser power was optimized for dual-beam laser joining of aluminum alloy to galvanized steel at high speed. The feasibility of joining as-received panels with lubricant was also explored. The identification of strain hardening models of aluminum alloys was conducted for the mechanical finite element analysis of the joint. Control of the molten pool solidification through the selection of laser beam configuration is one approach to improve joint quality. Laser joining of aluminum alloy AA 6111-T4 coach peel panels with the addition of AA 4047 filler wire was investigated using three configurations of laser beam: a single beam, dual beams in-line with the weld bead, and dual beams aligned perpendicular to the weld bead (herein

REDUNDANT ARRAY CONFIGURATIONS FOR 21 cm COSMOLOGY

Energy Technology Data Exchange (ETDEWEB)

Dillon, Joshua S.; Parsons, Aaron R., E-mail: jsdillon@berkeley.edu [Department of Astronomy, UC Berkeley, Berkeley, CA (United States)

2016-08-01

Realizing the potential of 21 cm tomography to statistically probe the intergalactic medium before and during the Epoch of Reionization requires large telescopes and precise control of systematics. Next-generation telescopes are now being designed and built to meet these challenges, drawing lessons from first-generation experiments that showed the benefits of densely packed, highly redundant arrays—in which the same mode on the sky is sampled by many antenna pairs—for achieving high sensitivity, precise calibration, and robust foreground mitigation. In this work, we focus on the Hydrogen Epoch of Reionization Array (HERA) as an interferometer with a dense, redundant core designed following these lessons to be optimized for 21 cm cosmology. We show how modestly supplementing or modifying a compact design like HERA’s can still deliver high sensitivity while enhancing strategies for calibration and foreground mitigation. In particular, we compare the imaging capability of several array configurations, both instantaneously (to address instrumental and ionospheric effects) and with rotation synthesis (for foreground removal). We also examine the effects that configuration has on calibratability using instantaneous redundancy. We find that improved imaging with sub-aperture sampling via “off-grid” antennas and increased angular resolution via far-flung “outrigger” antennas is possible with a redundantly calibratable array configuration.

Optimization Specifications for CUDA Code Restructuring Tool

KAUST Repository

Khan, Ayaz

2017-01-01

and convert it into an optimized CUDA kernel with user directives in a configuration file for guiding the compiler. RTCUDA also allows transparent invocation of the most optimized external math libraries like cuSparse and cuBLAS enabling efficient design

Transverse versus longitudinal tripolar configuration for selective stimulation with multipolar cuff electrodes.

Science.gov (United States)

Nielsen, Thomas N; Kurstjens, G A Mathijs; Struijk, Johannes J

2011-04-01

The ability to stimulate subareas of a nerve selectively is highly desirable, since it has the potential of simplifying surgery to implanting one cuff on a large nerve instead of many cuffs on smaller nerves or muscles, or alternatively can improve function where surgical access to the smaller nerves is limited. In this paper, stimulation was performed with a four-channel multipolar cuff electrode implanted on the sciatic nerve of nine rabbits to compare the extensively researched longitudinal tripolar configuration with the transverse tripolar configuration, which has received less interest. The performance of these configurations was evaluated in terms of selectivity in recruitment of the three branches of the sciatic nerve. The results showed that the transverse configuration was able to selectively activate the sciatic nerve branches to a functionally relevant level in more cases than the longitudinal configuration (20/27 versus 11/27 branches) and overall achieved a higher mean selectivity [0.79 ± 0.13 versus 0.61 ± 0.09 (mean ± standard deviation)]. The transverse configuration was most successful at recruiting the small cutaneous and medium-sized peroneal branches, and less successful at recruiting the large tibial nerve.

CONFIGURATION GENERATOR MODEL

International Nuclear Information System (INIS)

Alsaed, A.

2004-01-01

''The Disposal Criticality Analysis Methodology Topical Report'' prescribes an approach to the methodology for performing postclosure criticality analyses within the monitored geologic repository at Yucca Mountain, Nevada. An essential component of the methodology is the ''Configuration Generator Model for In-Package Criticality'' that provides a tool to evaluate the probabilities of degraded configurations achieving a critical state. The configuration generator model is a risk-informed, performance-based process for evaluating the criticality potential of degraded configurations in the monitored geologic repository. The method uses event tree methods to define configuration classes derived from criticality scenarios and to identify configuration class characteristics (parameters, ranges, etc.). The probabilities of achieving the various configuration classes are derived in part from probability density functions for degradation parameters. The NRC has issued ''Safety Evaluation Report for Disposal Criticality Analysis Methodology Topical Report, Revision 0''. That report contained 28 open items that required resolution through additional documentation. Of the 28 open items, numbers 5, 6, 9, 10, 18, and 19 were concerned with a previously proposed software approach to the configuration generator methodology and, in particular, the k eff regression analysis associated with the methodology. However, the use of a k eff regression analysis is not part of the current configuration generator methodology and, thus, the referenced open items are no longer considered applicable and will not be further addressed

Artificial immune system algorithm in VLSI circuit configuration

Science.gov (United States)

Mansor, Mohd. Asyraf; Sathasivam, Saratha; Kasihmuddin, Mohd Shareduwan Mohd

2017-08-01

In artificial intelligence, the artificial immune system is a robust bio-inspired heuristic method, extensively used in solving many constraint optimization problems, anomaly detection, and pattern recognition. This paper discusses the implementation and performance of artificial immune system (AIS) algorithm integrated with Hopfield neural networks for VLSI circuit configuration based on 3-Satisfiability problems. Specifically, we emphasized on the clonal selection technique in our binary artificial immune system algorithm. We restrict our logic construction to 3-Satisfiability (3-SAT) clauses in order to outfit with the transistor configuration in VLSI circuit. The core impetus of this research is to find an ideal hybrid model to assist in the VLSI circuit configuration. In this paper, we compared the artificial immune system (AIS) algorithm (HNN-3SATAIS) with the brute force algorithm incorporated with Hopfield neural network (HNN-3SATBF). Microsoft Visual C++ 2013 was used as a platform for training, simulating and validating the performances of the proposed network. The results depict that the HNN-3SATAIS outperformed HNN-3SATBF in terms of circuit accuracy and CPU time. Thus, HNN-3SATAIS can be used to detect an early error in the VLSI circuit design.

Proposal of a fluid flow layout to improve the heat transfer in the active absorber surface of solar central cavity receivers

International Nuclear Information System (INIS)

Montes, M.J.; Rovira, A.; Martínez-Val, J.M.; Ramos, A.

2012-01-01

The main objective of concentrated solar power is to increase the thermal energy of a fluid, for the fluid to be used, for example, in a power cycle to generate electricity. Such applications present the requirement of appropriately designing the receiver active absorber surface, as the incident radiation flux can be very high. Besides that, the solar image in the receiver is not uniform, so conventional boilers designs are not well suited for these purposes. That point is particularly critical in solar central receivers systems (CRS), where concentrated solar flux is usually above 500 kW/m 2 , causing thermal and mechanical stress in the absorber panels. This paper analyzes a new thermofluidynamic design of a solar central receiver, which optimizes the heat transfer in the absorber surface. This conceptual receiver presents the following characteristics: the fluid flow pattern is designed according to the radiation flux map symmetry, so more uniform fluid temperatures at the receiver outlet are achieved; the heat transfer irreversibilities are reduced by circulating the fluid from the lower temperature region to the higher temperature region of the absorber surface; the width of each pass is adjusted to the solar flux gradient, to get lower temperature differences between the side tubes of the same pass; and the cooling requirement is ensured by means of adjusting the fluid flow velocity per tube, taking into account the pressure drop. This conceptual scheme has been applied to the particular case of a molten salt single cavity receiver, although the configuration proposed is suitable for other receiver designs and working fluids. - Highlights: ► The solar receiver design proposed optimizes heat transfer in the absorber surface. ► The fluid flow pattern is designed according to the solar flux map symmetry at noon. ► The fluid circulates from the lower to the higher temperature regions. ► The width of each pass is adjusted to the solar flux gradient. �

A multi-agent based intelligent configuration method for aircraft fleet maintenance personnel

Directory of Open Access Journals (Sweden)

Feng Qiang

2014-04-01

Full Text Available A multi-agent based fleet maintenance personnel configuration method is proposed to solve the mission oriented aircraft fleet maintenance personnel configuration problem. The maintenance process of an aircraft fleet is analyzed first. In the process each aircraft contains multiple parts, and different parts are repaired by personnel with different majors and levels. The factors and their relationship involved in the process of maintenance are analyzed and discussed. Then the whole maintenance process is described as a 3-layer multi-agent system (MAS model. A communication and reasoning strategy among the agents is put forward. A fleet maintenance personnel configuration algorithm is proposed based on contract net protocol (CNP. Finally, a fleet of 10 aircraft is studied for verification purposes. A mission type with 3 waves of continuous dispatch is imaged. Compared with the traditional methods that can just provide configuration results, the proposed method can provide optimal maintenance strategies as well.

A Flexible Power Electronics Configuration for Coupling Renewable Energy Sources

Directory of Open Access Journals (Sweden)

Mattia Filippini

2015-05-01

Full Text Available A combination of series, parallel and multilevel power electronics has been investigated as a potential interface for two different types of renewable energy sources and in order to reach higher power levels. Renewable energy sources are typically dispersed in a territory, and sources, like wind and solar, allow small to medium-scale generation of electricity. The configuration investigated in this article aims at adapting the coupling solution to the specific generation characteristics of the renewable energy source to make it fit the electrical network. The configuration consists of a combination of three-phase multilevel converters and single-phase inverters, which are designed to provide flexibility, high power quality and high efficiency. A detailed analysis and simulation is performed to identify the properties in conjunction with the electrical grid requirements and the potential challenges encountered during operation. An optimized operation example of wind generation combined with solar PV generation is presented to exemplify the flexibility and benefits of the proposed configuration.

Supply strategy configuration in fragmented production systems: An empirical study

Directory of Open Access Journals (Sweden)

Claudia Chackelson

2013-07-01

Full Text Available Purpose: Companies survive in saturated markets trying to be more productive and more efficient. In this context, it becomes critical for companies to manage the entire supply network to optimize overall performance.  Hence, the supply strategy plays an important role because it influences the way in which production and logistics network has to be configured and managed. This paper explores the benefits obtained configuring different supply strategies adapted to customer needs.Design/methodology/approach: For this purpose a case research from a Tier 2 point of view of the supply chain has been conducted. Findings and Originality/value: The case research demonstrates that a higher service level, less holding costs and increase turnovers can be obtained implementing the adequate supply strategy. Originality/value: There is a scarcity of research specifically focused on applied Supply Chain Principles within network configuration processes. Moreover, there are few empirical studies of global Tier 2 with multiple decoupling points into its supply chain network.

Exploration of Stellarator Configuration Space with Global Search Methods

International Nuclear Information System (INIS)

Mynick, H.E.; Pomphrey, N.; Ethier, S.

2001-01-01

An exploration of stellarator configuration space z for quasi-axisymmetric stellarator (QAS) designs is discussed, using methods which provide a more global view of that space. To this end, we have implemented a ''differential evolution'' (DE) search algorithm in an existing stellarator optimizer, which is much less prone to become trapped in local, suboptimal minima of the cost function chi than the local search methods used previously. This search algorithm is complemented by mapping studies of chi over z aimed at gaining insight into the results of the automated searches. We find that a wide range of the attractive QAS configurations previously found fall into a small number of classes, with each class corresponding to a basin of chi(z). We develop maps on which these earlier stellarators can be placed, the relations among them seen, and understanding gained into the physics differences between them. It is also found that, while still large, the region of z space containing practically realizable QAS configurations is much smaller than earlier supposed

Lift Optimization Study of a Multi-Element Three-Segment Variable Camber Airfoil

Science.gov (United States)

Kaul, Upender K.; Nguyen, Nhan T.

2016-01-01

This paper reports a detailed computational high-lift study of the Variable Camber Continuous Trailing Edge Flap (VCCTEF) system carried out to explore the best VCCTEF designs, in conjunction with a leading edge flap called the Variable Camber Krueger (VCK), for take-off and landing. For this purpose, a three-segment variable camber airfoil employed as a performance adaptive aeroelastic wing shaping control effector for a NASA Generic Transport Model (GTM) in landing and take-off configurations is considered. The objective of the study is to define optimal high-lift VCCTEF settings and VCK settings/configurations. A total of 224 combinations of VCK settings/configurations and VCCTEF settings are considered for the inboard GTM wing, where the VCCTEFs are configured as a Fowler flap that forms a slot between the VCCTEF and the main wing. For the VCK settings of deflection angles of 55deg, 60deg and 65deg, 18, 19 and 19 vck configurations, respectively, were considered for each of the 4 different VCCTEF deflection settings. Different vck configurations were defined by varying the horizontal and vertical distance of the vck from the main wing. A computational investigation using a Reynolds-Averaged Navier-Stokes (RANS) solver was carried out to complement a wind-tunnel experimental study covering three of these configurations with the goal of identifying the most optimal high-lift configurations. Four most optimal high-lift configurations, corresponding to each of the VCK deflection settings, have been identified out of all the different configurations considered in this study yielding the highest lift performance.

Waste receiving and processing plant control system; system design description

Energy Technology Data Exchange (ETDEWEB)

LANE, M.P.

1999-02-24

The Plant Control System (PCS) is a heterogeneous computer system composed of numerous sub-systems. The PCS represents every major computer system that is used to support operation of the Waste Receiving and Processing (WRAP) facility. This document, the System Design Description (PCS SDD), includes several chapters and appendices. Each chapter is devoted to a separate PCS sub-system. Typically, each chapter includes an overview description of the system, a list of associated documents related to operation of that system, and a detailed description of relevant system features. Each appendice provides configuration information for selected PCS sub-systems. The appendices are designed as separate sections to assist in maintaining this document due to frequent changes in system configurations. This document is intended to serve as the primary reference for configuration of PCS computer systems. The use of this document is further described in the WRAP System Configuration Management Plan, WMH-350, Section 4.1.

Waste receiving and processing plant control system; system design description

International Nuclear Information System (INIS)

LANE, M.P.

1999-01-01

The Plant Control System (PCS) is a heterogeneous computer system composed of numerous sub-systems. The PCS represents every major computer system that is used to support operation of the Waste Receiving and Processing (WRAP) facility. This document, the System Design Description (PCS SDD), includes several chapters and appendices. Each chapter is devoted to a separate PCS sub-system. Typically, each chapter includes an overview description of the system, a list of associated documents related to operation of that system, and a detailed description of relevant system features. Each appendice provides configuration information for selected PCS sub-systems. The appendices are designed as separate sections to assist in maintaining this document due to frequent changes in system configurations. This document is intended to serve as the primary reference for configuration of PCS computer systems. The use of this document is further described in the WRAP System Configuration Management Plan, WMH-350, Section 4.1

Front end power dissipation minimization and optimal transmission rate for wireless receivers

NARCIS (Netherlands)

Heuvel, van den J.H.C.; Wu, Y.; Baltus, P.G.M.; Linnartz, J.P.M.G.; Roermund, van A.H.M.

2014-01-01

Most wireless battery-operated devices spend more energy receiving than transmitting. Hence, minimizing the power dissipation in the receiver front end, which, in many cases, is the prominent power consuming part of the receiver, is an important challenge. This paper addresses this challenge by

Neoclassical bootstrap current and transport in optimized stellarator configurations

International Nuclear Information System (INIS)

Maassberg, H.; Lotz, W.; Nuehrenberg, J.

1993-01-01

The neoclassical bootstrap current properties of optimized stellarators are analyzed in the relevant mean-free-path regimes and compared with the neoclassical transport properties. Two methods---global Monte Carlo simulation [Phys. Fluids 31, 2984 (1988)], and local analysis with the drift kinetic equation solver code [Phys. Fluids B 1, 563 (1989)]---are employed and good agreement is obtained. Full consistency with the elimination of the bootstrap current and favorable neoclassical transport are found

Autonomous Operation of Super-Regenerative Receiver in BAN

NARCIS (Netherlands)

Kalyanasundaram, P.; Huang, L.; Dolmans, G.; Imamura, K.

2012-01-01

Super-regenerative receiver is one of the potential candidates to achieve ultra low power wireless communication in body area network (BAN). The main limitations of the super-regenerative receiver include the difficulty in choosing a good quench waveform to optimize its sensitivity and selectivity,

Optimization under uncertainty of parallel nonlinear energy sinks

Science.gov (United States)

Boroson, Ethan; Missoum, Samy; Mattei, Pierre-Olivier; Vergez, Christophe

2017-04-01

Nonlinear Energy Sinks (NESs) are a promising technique for passively reducing the amplitude of vibrations. Through nonlinear stiffness properties, a NES is able to passively and irreversibly absorb energy. Unlike the traditional Tuned Mass Damper (TMD), NESs do not require a specific tuning and absorb energy over a wider range of frequencies. Nevertheless, they are still only efficient over a limited range of excitations. In order to mitigate this limitation and maximize the efficiency range, this work investigates the optimization of multiple NESs configured in parallel. It is well known that the efficiency of a NES is extremely sensitive to small perturbations in loading conditions or design parameters. In fact, the efficiency of a NES has been shown to be nearly discontinuous in the neighborhood of its activation threshold. For this reason, uncertainties must be taken into account in the design optimization of NESs. In addition, the discontinuities require a specific treatment during the optimization process. In this work, the objective of the optimization is to maximize the expected value of the efficiency of NESs in parallel. The optimization algorithm is able to tackle design variables with uncertainty (e.g., nonlinear stiffness coefficients) as well as aleatory variables such as the initial velocity of the main system. The optimal design of several parallel NES configurations for maximum mean efficiency is investigated. Specifically, NES nonlinear stiffness properties, considered random design variables, are optimized for cases with 1, 2, 3, 4, 5, and 10 NESs in parallel. The distributions of efficiency for the optimal parallel configurations are compared to distributions of efficiencies of non-optimized NESs. It is observed that the optimization enables a sharp increase in the mean value of efficiency while reducing the corresponding variance, thus leading to more robust NES designs.

Non-newtonian heat transfer on a plate heat exchanger with generalized configurations

Energy Technology Data Exchange (ETDEWEB)

Carezzato, A.; Tadini, C.C.; Gut, J.A.W. [Department of Chemical Engineering, Escola Politecnica, University of Sao Paulo, Sao Paulo (Brazil); Alcantara, M.R. [Department of Fundamental Chemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo (Brazil); Telis-Romero, J. [Department of Food Engineering and Technology, Universidade Estadual Paulista, Sao Jose do Rio Preto (Brazil)

2007-01-15

For the configuration optimization of plate heat exchangers (PHEs), the mathematical models for heat transfer and pressure drop must be valid for a wide range of operational conditions of all configurations of the exchanger or the design results may be compromised. In this investigation, the thermal model of a PHE is adjusted to fit experimental data obtained from non-Newtonian heat transfer for eight different configurations, using carboxymethylcellulose solutions (CMC) as test fluid. Although it is possible to successfully adjust the model parameters, Newtonian and non-Newtonian heat transfer cannot be represented by a single generalized correlation. In addition, the specific heat, thermal conductivity and power-law rheological parameters of CMC solutions were correlated with temperature, over a range compatible with a continuous pasteurization process. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Using qualimetric engineering and extremal analysis to optimize a proton exchange membrane fuel cell stack

International Nuclear Information System (INIS)

Besseris, George J.

2014-01-01

Highlights: • We consider the optimal configuration of a PEMFC stack. • We utilize qualimetric engineering tools (Taguchi screening, regression analysis). • We achieve analytical solution on a restructured power-law fitting. • We discuss the Pt-cost involvement in the unit and area minimization scope. - Abstract: The optimal configuration of the proton exchange membrane fuel-cell (PEMFC) stack has received attention recently because of its potential use as an isolated energy distributor for household needs. In this work, the original complex problem for generating an optimal PEMFC stack based on the number of cell units connected in series and parallel arrangements as well as on the cell area is revisited. A qualimetric engineering strategy is formulated which is based on quick profiling the PEMFC stack voltage response. Stochastic screening is initiated by employing an L 9 (3 3 ) Taguchi-type OA for partitioning numerically the deterministic expression of the output PEMFC stack voltage such that to facilitate the sizing of the magnitude of the individual effects. The power and current household specifications for the stack system are maintained at the typical settings of 200 W at 12 V, respectively. The minimization of the stack total-area requirement becomes explicit in this work. The relationship of cell voltage against cell area is cast into a power-law model by regression fitting that achieves a coefficient of determination value of 99.99%. Thus, the theoretical formulation simplifies into a non-linear extremal problem with a constrained solution due to a singularity which is solved analytically. The optimal solution requires 22 cell units connected in series where each unit is designed with an area value of 151.4 cm 2 . It is also demonstrated how to visualize the optimal solution using the graphical method of operating lines. The total area of 3270.24 cm 2 becomes a new benchmark for the optimal design of the studied PEMFC stack configuration. It is

Optimization by record dynamics

DEFF Research Database (Denmark)

Barettin, Daniele; Sibani, Paolo

2014-01-01

Large dynamical changes in thermalizing glassy systems are triggered by trajectories crossing record sized barriers, a behavior revealing the presence of a hierarchical structure in configuration space. The observation is here turned into a novel local search optimization algorithm dubbed record...... dynamics optimization,or RDO. RDO uses the Metropolis rule to accept or reject candidate solutions depending on the value of a parameter akin to the temperature and minimizes the cost function of the problem at hand through cycles where its ‘temperature’ is raised and subsequently decreased in order......), is applied to the same problem as a benchmark. RDO and PT turn out to produce solutions of similar quality for similar numerical effort, but RDO is simpler to program and additionally yields geometrical information on the system’s configuration space which is of interest in many applications. In particular...

Onset of pseudo-thermal equilibrium within configurations and super-configurations

International Nuclear Information System (INIS)

Busquet, Michel

2006-01-01

Level populations within a configuration and configuration populations within super-configuration or within one ion are shown to follow a Boltzmann law at some effective temperature different from the actual electron temperature (as it would be when Griem criterion is valid). Origin of this pseudo-thermal equilibrium is discussed and basis of a model are presented

Onset of pseudo-thermal equilibrium within configurations and super-configurations

Energy Technology Data Exchange (ETDEWEB)

Busquet, Michel [ARTEP Inc., 2922 Excelsior Springs Court, Elicott City, MD 21042 (United States)]. E-mail: busquet@this.nrl.navy.mil

2006-05-15

Level populations within a configuration and configuration populations within super-configuration or within one ion are shown to follow a Boltzmann law at some effective temperature different from the actual electron temperature (as it would be when Griem criterion is valid). Origin of this pseudo-thermal equilibrium is discussed and basis of a model are presented.

Eco-efficiency and control loop configuration for recycle systems

Energy Technology Data Exchange (ETDEWEB)

Munir, Muhammad Tajammal; Yu, Wei; Young, Brent P. [The University of Auckland, Auckland (New Zealand)

2013-05-15

To integrate measurements of eco-efficiency with control loop configuration has become an important topic since all industrial processes/plants are requested to increase their eco-efficiency. The exergy eco-efficiency factor, a new measure of eco-efficiency for control loop configuration, has been developed recently. The exergy eco-efficiency factor is based on the thermodynamic concept of exergy, which can be used to analyze a process in terms of its efficiency. The combination of the relative gain array (RGA), NI, CN, dynamic RGA, and the exergy eco-efficiency factor will help guide the process designer to find the optimal control design with low operating cost/eco-efficiency. In this paper, we validate the proposed exergy eco-efficiency factor for processes with recycles which are very common industrially.

Eco-efficiency and control loop configuration for recycle systems

International Nuclear Information System (INIS)

Munir, Muhammad Tajammal; Yu, Wei; Young, Brent P.

2013-01-01

To integrate measurements of eco-efficiency with control loop configuration has become an important topic since all industrial processes/plants are requested to increase their eco-efficiency. The exergy eco-efficiency factor, a new measure of eco-efficiency for control loop configuration, has been developed recently. The exergy eco-efficiency factor is based on the thermodynamic concept of exergy, which can be used to analyze a process in terms of its efficiency. The combination of the relative gain array (RGA), NI, CN, dynamic RGA, and the exergy eco-efficiency factor will help guide the process designer to find the optimal control design with low operating cost/eco-efficiency. In this paper, we validate the proposed exergy eco-efficiency factor for processes with recycles which are very common industrially

FPGA fabric specific optimization for RLT design

International Nuclear Information System (INIS)

Perwaiz, A.; Khan, S.A.

2010-01-01

This paper proposes a technique custom to the optimization requirements suited for a particular family of Field Programmable Gate Arrays (FPGAs). As FPGAs have introduced re configurable black boxes there is a need to perform optimization across FPGAs slice fabric in order to achieve optimum performance. Though the Register Transfer Level (RTL) Hardware Descriptive Language (HDL) code should be technology independent but in many design instances it is imperative to understand the target technology especially once the target device embeds dedicated arithmetic blocks. No matter what the degree of optimization of the algorithm is, the configuration of target device plays an important role as far as the device utilization and path delays are concerned Index Terms: Field Programmable Gate Arrays (FPGA), Compression Tree, Bit Width Reduction, Look Ahead Pipelining. (author)

THE OPTIMIZATION OF ELECTRODYNAMIC CONFIGURATION OBJECT WITH THE DESIRED CHARACTERISTICS OF SCATTERING.

Directory of Open Access Journals (Sweden)

A. P. Preobrazhensky

2017-02-01

Full Text Available This paper considers the problem of optimization of the characteristics of scattering of electromagnetic waves on periodic electrodynamic structure. The solution of the scattering problem is based on the method of integral equations, the optimization of the characteristics is based on the genetic algorithm. Recommendations on the parameters of the periodic structure under given angles are given.

Self-Optimization of LTE Networks Utilizing Celnet Xplorer

CERN Document Server

Buvaneswari, A; Polakos, Paul; Buvaneswari, Arumugam

2010-01-01

In order to meet demanding performance objectives in Long Term Evolution (LTE) networks, it is mandatory to implement highly efficient, autonomic self-optimization and configuration processes. Self-optimization processes have already been studied in second generation (2G) and third generation (3G) networks, typically with the objective of improving radio coverage and channel capacity. The 3rd Generation Partnership Project (3GPP) standard for LTE self-organization of networks (SON) provides guidelines on self-configuration of physical cell ID and neighbor relation function and self-optimization for mobility robustness, load balancing, and inter-cell interference reduction. While these are very important from an optimization perspective of local phenomenon (i.e., the eNodeB's interaction with its neighbors), it is also essential to architect control algorithms to optimize the network as a whole. In this paper, we propose a Celnet Xplorer-based SON architecture that allows detailed analysis of network performan...

Operational Dynamic Configuration Analysis

Science.gov (United States)

Lai, Chok Fung; Zelinski, Shannon

2010-01-01

Sectors may combine or split within areas of specialization in response to changing traffic patterns. This method of managing capacity and controller workload could be made more flexible by dynamically modifying sector boundaries. Much work has been done on methods for dynamically creating new sector boundaries [1-5]. Many assessments of dynamic configuration methods assume the current day baseline configuration remains fixed [6-7]. A challenging question is how to select a dynamic configuration baseline to assess potential benefits of proposed dynamic configuration concepts. Bloem used operational sector reconfigurations as a baseline [8]. The main difficulty is that operational reconfiguration data is noisy. Reconfigurations often occur frequently to accommodate staff training or breaks, or to complete a more complicated reconfiguration through a rapid sequence of simpler reconfigurations. Gupta quantified a few aspects of airspace boundary changes from this data [9]. Most of these metrics are unique to sector combining operations and not applicable to more flexible dynamic configuration concepts. To better understand what sort of reconfigurations are acceptable or beneficial, more configuration change metrics should be developed and their distribution in current practice should be computed. This paper proposes a method to select a simple sequence of configurations among operational configurations to serve as a dynamic configuration baseline for future dynamic configuration concept assessments. New configuration change metrics are applied to the operational data to establish current day thresholds for these metrics. These thresholds are then corroborated, refined, or dismissed based on airspace practitioner feedback. The dynamic configuration baseline selection method uses a k-means clustering algorithm to select the sequence of configurations and trigger times from a given day of operational sector combination data. The clustering algorithm selects a simplified

Ansible configuration management

CERN Document Server

Hall, Daniel

2013-01-01

Ansible Configuration Management"" is a step-by-step tutorial that teaches the use of Ansible for configuring Linux machines.This book is intended for anyone looking to understand the basics of Ansible. It is expected that you will have some experience of how to set up and configure Linux machines. In parts of the book we cover configuration files of BIND, MySQL, and other Linux daemons, therefore a working knowledge of these would be helpful but are certainly not required.

Development And Test of A Digitally Steered Antenna Array for The Navigator GPS Receiver

Science.gov (United States)

Pinto, Heitor David; Valdez, Jennifer E.; Winternitz, Luke M. B.; Hassouneh, Munther A.; Price, Samuel R.

2012-01-01

Global Positioning System (GPS)-based navigation has become common for low-Earth orbit spacecraft as the signal environment is similar to that on the Earth s surface. The situation changes abruptly, however, for spacecraft whose orbital altitudes exceed that of the GPS constellation. Visibility is dramatically reduced and signals that are present may be very weak and more susceptible to interference. GPS receivers effective at these altitudes require increased sensitivity, which often requires a high-gain antenna. Pointing such an antenna can pose a challenge. One efficient approach to mitigate these problems is the use of a digitally steered antenna array. Such an antenna can optimally allocate gain toward desired signal sources and away from interferers. This paper presents preliminary results in the development and test of a digitally steered antenna array for the Navigator GPS research program at NASA s Goddard Space Flight Center. In particular, this paper highlights the development of an array and front-end electronics, the development and test of a real-time software GPS receiver, and implementation of three beamforming methods for combining the signals from the array. Additionally, this paper discusses the development of a GPS signal simulator which produces digital samples of the GPS L1C/A signals as they would be received by an arbitrary antenna array configuration. The simulator models transmitter and receiver dynamics, near-far and multipath interference, and has been a critical component in both the development and test of the GPS receiver. The GPS receiver system was tested with real and simulated GPS signals. Preliminary results show that performance improvement was achieved in both the weak signal and interference environments, matching analytical predictions. This paper summarizes our initial findings and discusses the advantages and limitations of the antenna array and the various beamforming methods.

Ideal heat transfer conditions for tubular solar receivers with different design constraints

Science.gov (United States)

Kim, Jin-Soo; Potter, Daniel; Gardner, Wilson; Too, Yen Chean Soo; Padilla, Ricardo Vasquez

2017-06-01

The optimum heat transfer condition for a tubular type solar receiver was investigated for various receiver pipe size, heat transfer fluid, and design requirement and constraint(s). Heat transfer of a single plain receiver pipe exposed to concentrated solar energy was modelled along the flow path of the heat transfer fluid. Three different working fluids, molten salt, sodium, and supercritical carbon dioxide (sCO2) were considered in the case studies with different design conditions. The optimized ideal heat transfer condition was identified through fast iterative heat transfer calculations solving for all relevant radiation, conduction and convection heat transfers throughout the entire discretized tubular receiver. The ideal condition giving the best performance was obtained by finding the highest acceptable solar energy flux optimally distributed to meet different constraint(s), such as maximum allowable material temperature of receiver, maximum allowable film temperature of heat transfer fluid, and maximum allowable stress of receiver pipe material. The level of fluid side turbulence (represented by pressure drop in this study) was also optimized to give the highest net power production. As the outcome of the study gives information on the most ideal heat transfer condition, it can be used as a useful guideline for optimal design of a real receiver and solar field in a combined manner. The ideal heat transfer condition is especially important for high temperature tubular receivers (e.g. for supplying heat to high efficiency Brayton cycle turbines) where the system design and performance is tightly constrained by the receiver pipe material strength.

Numerical Experiments of Counterflowiing Jet Effects on Supersonic Slender-Body Configurations

Science.gov (United States)

Venkatachari, Balaji Shankar; Mullane, Michael; Cheng, Gary C.; Chang, Chau-Lyan

2015-01-01

Previous studies have demonstrated that the use of counterflowing jets can greatly reduce the drag and heat loads on blunt-body geometries, especially when the long penetration mode jet condition can be established. Previously, the authors had done some preliminary numerical studies to determine the ability to establish long penetration mode jets on a typical Mach 1.6 slender configuration, and study its impact on the boom signature. The results indicated that a jet with a longer penetration length was required to achieve any impact on the boom signature of a typical Mach 1.6 slender configuration. This paper focuses on an in-depth parametric study, done using the space-time conservation element solution element Navier-Stokes flow solver, for investigating the effect of various counterflowing jet conditions/configurations on two supersonic slender-body models (cone-cylinder and quartic body of revolution). The study is aimed at gaining a better understanding of the relationship between the shock penetration length and reduction of drag and boom signature for these two supersonic slender-body configurations. Different jet flow rates, Mach numbers, nozzle jet exit diameters and jet-to-base diameter ratios were examined. The results show the characteristics of a short-to-long-to-short penetration-mode pattern with the increase of jet mass flow rates, observed across various counterflowing jet nozzle configurations. Though the optimal shock penetration length for potential boom-signature mitigation is tied to the long penetration mode, it often results in a very unsteady flow and leads to large oscillations of surface pressure and drag. Furthermore, depending on the geometry of the slender body, longer jet penetration did not always result in maximum drag reduction. For the quartic geometry, the maximum drag reduction corresponds well to the longest shock penetration length, while this was not the case for the cone-cylinder-as the geometry was already optimized for

A topology optimization method based on the level set method for the design of negative permeability dielectric metamaterials

DEFF Research Database (Denmark)

Otomori, Masaki; Yamada, Takayuki; Izui, Kazuhiro

2012-01-01

This paper presents a level set-based topology optimization method for the design of negative permeability dielectric metamaterials. Metamaterials are artificial materials that display extraordinary physical properties that are unavailable with natural materials. The aim of the formulated...... optimization problem is to find optimized layouts of a dielectric material that achieve negative permeability. The presence of grayscale areas in the optimized configurations critically affects the performance of metamaterials, positively as well as negatively, but configurations that contain grayscale areas...... are highly impractical from an engineering and manufacturing point of view. Therefore, a topology optimization method that can obtain clear optimized configurations is desirable. Here, a level set-based topology optimization method incorporating a fictitious interface energy is applied to a negative...

A methodology for optimal sizing of autonomous hybrid PV/wind system

International Nuclear Information System (INIS)

Diaf, S.; Diaf, D.; Belhamel, M.; Haddadi, M.; Louche, A.

2007-01-01

The present paper presents a methodology to perform the optimal sizing of an autonomous hybrid PV/wind system. The methodology aims at finding the configuration, among a set of systems components, which meets the desired system reliability requirements, with the lowest value of levelized cost of energy. Modelling a hybrid PV/wind system is considered as the first step in the optimal sizing procedure. In this paper, more accurate mathematical models for characterizing PV module, wind generator and battery are proposed. The second step consists to optimize the sizing of a system according to the loss of power supply probability (LPSP) and the levelized cost of energy (LCE) concepts. Considering various types and capacities of system devices, the configurations, which can meet the desired system reliability, are obtained by changing the type and size of the devices systems. The configuration with the lowest LCE gives the optimal choice. Applying this method to an assumed PV/wind hybrid system to be installed at Corsica Island, the simulation results show that the optimal configuration, which meet the desired system reliability requirements (LPSP=0) with the lowest LCE, is obtained for a system comprising a 125 W photovoltaic module, one wind generator (600 W) and storage batteries (using 253 Ah). On the other hand, the device system choice plays an important role in cost reduction as well as in energy production

Risk-based configuration control

International Nuclear Information System (INIS)

Szikszai, T.

1997-01-01

The presentation discusses the following issues: The Configuration Control; The Risk-based Configuration Control (during power operation mode, and during shutdown mode). PSA requirements. Use of Risk-based Configuration Control System. Configuration Management (basic elements, benefits, information requirements)

System engineering and configuration management in ITER

International Nuclear Information System (INIS)

Chiocchio, S.; Martin, E.; Barabaschi, P.; Bartels, Hans Werner; How, J.; Spears, W.

2007-01-01

The construction of ITER will represent a major challenge for the fusion community at large, because of the intrinsic complexity of the tokamak design, the large number of different systems which are all essential for its operation, the worldwide distribution of the design activities and the unusual procurement scheme based on a combination of in-kind and directly funded deliverables. A key requirement for the success of such a large project is that a systematic approach to ensure the consistency of the design with the required performance is adopted. Also, effective project management methods, tools and working practices must be deployed to facilitate the communication and collaboration among the institutions and industries involved in the project. The authors have been involved in the definition and practical implementation of the design integration and configuration control structure inside ITER and in the system engineering process during the selection and optimization of the machine configuration. In parallel, they have assessed design, drawing and documentation management software to be used for the construction phase. Here, they describe the experience gained in recent years, explain the drivers behind the selection of the documents and drawings management systems, and illustrate the scope and issues of the configuration management activities to ensure the congruence of the design, to control and track the design changes and to manage the interfaces among the ITER systems

Optimizing signal recycling for detecting a stochastic gravitational-wave background

Science.gov (United States)

Tao, Duo; Christensen, Nelson

2018-06-01

Signal recycling is applied in laser interferometers such as the Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO) to increase their sensitivity to gravitational waves. In this study, signal recycling configurations for detecting a stochastic gravitational wave background are optimized based on aLIGO parameters. Optimal transmission of the signal recycling mirror (SRM) and detuning phase of the signal recycling cavity under a fixed laser power and low-frequency cutoff are calculated. Based on the optimal configurations, the compatibility with a binary neutron star (BNS) search is discussed. Then, different laser powers and low-frequency cutoffs are considered. Two models for the dimensionless energy density of gravitational waves , the flat model and the model, are studied. For a stochastic background search, it is found that an interferometer using signal recycling has a better sensitivity than an interferometer not using it. The optimal stochastic search configurations are typically found when both the SRM transmission and the signal recycling detuning phase are low. In this region, the BNS range mostly lies between 160 and 180 Mpc. When a lower laser power is used the optimal signal recycling detuning phase increases, the optimal SRM transmission increases and the optimal sensitivity improves. A reduced low-frequency cutoff gives a better sensitivity limit. For both models of , a typical optimal sensitivity limit on the order of 10‑10 is achieved at a reference frequency of Hz.

Energy Optimized Configuration of Concrete Element with PCM

DEFF Research Database (Denmark)

Pomianowski, Michal Zbigniew

fulfillment of the new requirements regarding the new energy frames. The concept presented and developed in the thesis focuses on the energy optimization and potential of the new product that could utilize the high thermal energy storage (TES) and thermally activated building system (TABS). The work...... investigates the potential of combining the microencapsulated phase change material (PCM) in the hollow core concrete deck element in order to increase the dynamic heat storage capacity of the internal envelope of the multi-storey buildings. Moreover, the study investigates the cooling capacity and performance...... of the concrete deck with PCM and integrated TABS and highlights limitations and challenges of the new technology. The presented work utilizes numerical methods to study the dynamic performance of the new product developed. Consequently, the experimental set-ups and methodologies are developed firstly...

Evaluation of the optimal diagnostic criteria for regional lymph node metastases of lung cancer on MR imaging by receiver operating characteristic curve

International Nuclear Information System (INIS)

Iwai, Naomichi; Yamaguchi, Yutaka

1991-01-01

MRI was performed in 78 primary lung cancer cases to evaluate the optimal diagnostic criteria for regional lymph node metastases. Receiver operating characteristic (ROC) curve analysis for 262 lymph nodes of the hilar and mediastinal regions showed that the optimal size criterion is 10 mm in the mean axis of nodal diameter. Employing this criterion, the diagnostic rates for hilar and mediastinal lymph nodes had a sensitivity of 75%, a specificity of 82%, and an overall accuracy of 79%. However, the diagnostic rates for subaortic, paraaortic, and hilar lymph nodes using the same criterion showed lower specificities than those for other nodes. It was suggested that evaluation by coronal section made the diagnosis for subaortic lymph nodes more precise. In the ROC curve analysis for each histologic type, it was thought that the optimal criterion for adenocarcinoma was 10 mm in the mean axis, and that the criteria for squamous cell carcinoma were 11 mm in the mean axis and 10 mm in the sort axis. (author)

Multidepot UAV Routing Problem with Weapon Configuration and Time Window

Directory of Open Access Journals (Sweden)

Tianren Zhou

2018-01-01

Full Text Available In recent wars, there is an increasing trend that unmanned aerial vehicles (UAVs are utilized to conduct military attacking missions. In this paper, we investigate a novel multidepot UAV routing problem with consideration of weapon configuration in the UAV and the attacking time window of the target. A mixed-integer linear programming model is developed to jointly optimize three kinds of decisions: the weapon configuration strategy in the UAV, the routing strategy of target, and the allocation strategy of weapons to targets. An adaptive large neighborhood search (ALNS algorithm is proposed for solving the problem, which is tested by randomly generated instances covering the small, medium, and large sizes. Experimental results confirm the effectiveness and robustness of the proposed ALNS algorithm.

Microstrip Antenna Design for Femtocell Coverage Optimization

Directory of Open Access Journals (Sweden)

Afaz Uddin Ahmed

2014-01-01

Full Text Available A mircostrip antenna is designed for multielement antenna coverage optimization in femtocell network. Interference is the foremost concern for the cellular operator in vast commercial deployments of femtocell. Many techniques in physical, data link and network-layer are analysed and developed to settle down the interference issues. A multielement technique with self-configuration features is analyzed here for coverage optimization of femtocell. It also focuses on the execution of microstrip antenna for multielement configuration. The antenna is designed for LTE Band 7 by using standard FR4 dielectric substrate. The performance of the proposed antenna in the femtocell application is discussed along with results.

Fuzzy logic control and optimization system

Science.gov (United States)

Lou, Xinsheng [West Hartford, CT

2012-04-17

A control system (300) for optimizing a power plant includes a chemical loop having an input for receiving an input signal (369) and an output for outputting an output signal (367), and a hierarchical fuzzy control system (400) operably connected to the chemical loop. The hierarchical fuzzy control system (400) includes a plurality of fuzzy controllers (330). The hierarchical fuzzy control system (400) receives the output signal (367), optimizes the input signal (369) based on the received output signal (367), and outputs an optimized input signal (369) to the input of the chemical loop to control a process of the chemical loop in an optimized manner.

Managing complexity of product mix and production flow in configure-to-order production systems

DEFF Research Database (Denmark)

Myrodia, Anna; Bonev, Martin; Hvam, Lars

2014-01-01

In designing configure-to-order production systems for a growing product variety, companies are challenged with an increased complexity for obtaining high productivity levels and cost-effectiveness. In academia several optimization methods and conceptual frameworks for substituting components, or...

Optimal configuration of a low-dose breast-specific gamma camera based on semiconductor CdZnTe pixelated detectors

Science.gov (United States)

Genocchi, B.; Pickford Scienti, O.; Darambara, DG

2017-05-01

Breast cancer is one of the most frequent tumours in women. During the ‘90s, the introduction of screening programmes allowed the detection of cancer before the palpable stage, reducing its mortality up to 50%. About 50% of the women aged between 30 and 50 years present dense breast parenchyma. This percentage decreases to 30% for women between 50 to 80 years. In these women, mammography has a sensitivity of around 30%, and small tumours are covered by the dense parenchyma and missed in the mammogram. Interestingly, breast-specific gamma-cameras based on semiconductor CdZnTe detectors have shown to be of great interest to early diagnosis. Infact, due to the high energy, spatial resolution, and high sensitivity of CdZnTe, molecular breast imaging has been shown to have a sensitivity of about 90% independently of the breast parenchyma. The aim of this work is to determine the optimal combination of the detector pixel size, hole shape, and collimator material in a low dose dual head breast specific gamma camera based on a CdZnTe pixelated detector at 140 keV, in order to achieve high count rate, and the best possible image spatial resolution. The optimal combination has been studied by modeling the system using the Monte Carlo code GATE. Six different pixel sizes from 0.85 mm to 1.6 mm, two hole shapes, hexagonal and square, and two different collimator materials, lead and tungsten were considered. It was demonstrated that the camera achieved higher count rates, and better signal-to-noise ratio when equipped with square hole, and large pixels (> 1.3 mm). In these configurations, the spatial resolution was worse than using small pixel sizes (< 1.3 mm), but remained under 3.6 mm in all cases.

Energy Optimized Configuration of Concrete Element with PCM

DEFF Research Database (Denmark)

Pomianowski, Michal Zbigniew

fulfillment of the new requirements regarding the new energy frames. The concept presented and developed in the thesis focuses on the energy optimization and potential of the new product that could utilize the high thermal energy storage (TES) and thermally activated building system (TABS). The work...... investigates the potential of combining the microencapsulated phase change material (PCM) in the hollow core concrete deck element in order to increase the dynamic heat storage capacity of the internal envelope of the multi-storey buildings. Moreover, the study investigates the cooling capacity and performance...... of the concrete deck with PCM and integrated TABS and highlights limitations and challenges of the new technology. Results from the full-scale investigation of dynamic heat storage capacity of decks indicated that there is no substantial difference between decks with extended heat transfer surface and one...

Impact of the fouling mechanism on enzymatic depolymerization of xylan in different configurations of membrane reactors

DEFF Research Database (Denmark)

Mohd Sueb, Mohd Shafiq Bin; Luo, Jianquan; Meyer, Anne S.

2017-01-01

In order to maximize enzymatic xylan depolymerization while simultaneously purifying the resulting monosaccharide (xylose), different ultrafiltration (UF) membrane reactor configurations were evaluated. Initial results showed that the two hydrolytic enzymes required for complete depolymerization...... which hindered enzymatic attack in addition to fouling. Reaction with both enzymes followed by UF was found to be the optimal configuration, providing at least 40% higher xylan hydrolysis than the cascade configuration (involving sequential reaction with each of the enzymes separately......) and the simultaneous reaction-filtration with both enzymes, respectively. This study thus confirmed that the reactor configuration has a crucial impact on the performance of both the reaction and the separation process of xylose during enzymatic xylan degradation, and that the type of fouling mechanism varies...

Effect of contacts configuration and location on selective stimulation of cuff electrode.

Science.gov (United States)

Taghipour-Farshi, Hamed; Frounchi, Javad; Ahmadiasl, Nasser; Shahabi, Parviz; Salekzamani, Yaghoub

2015-01-01

Cuff electrodes have been widely used chronically in different clinical applications. Advancements have been made in selective stimulation by using multi-contact cuff electrodes. Steering anodic current is a strategy to increase selectivity by reshaping and localizing electric fields. There are two configurations for contacts to be implemented in cuff, monopolar and tripolar. A cuff electrode with tripolar configuration can restrict the activation to a more localized region within a nerve trunk compared to a cuff with monopolar configuration and improve the selectivity. Anode contacts in tripolar configuration can be made in two structures, "ring" and "dot". In this study, the stimulation capabilities of these two structures were evaluated. The recruitment properties and the selectivity of stimulation were examined by measuring the electric potential produced by stimulation currents. The results of the present study indicated that using dot configuration, the current needed to stimulate fascicles in tripolar topologies would be reduced by 10%. It was also shown that stimulation threshold was increased by moving anode contacts inward the cuff. On the other hand, stimulation threshold was decreased by moving the anode contacts outward the cuff which would decrease selectivity, too. We conclude that dot configuration is a better choice for stimulation. Also, a cuff inward placement of 10% relative to the cuff length was near optimal.

Neutronic optimization of a LiAlO2 solid breeder blanket

International Nuclear Information System (INIS)

Levin, P.; Ghoniem, N.M.

1986-02-01

In this report, a pressurized lobular blanket configuration is neutronically optimized. Among the features of this blanket configuration are the use of beryllium and LiAlO 2 solid breeder pins in a cross-flow configuration in a helium coolant. One-dimensional neutronic optimization calculations are performed to maximize the tritium breeding ratio (TER). The procedure involves spatial allocations of Be, LiAlO 2 , 9-C (ferritic steel), and He; in such a way as to maximize the TBR subject to several material, engineering and geometrical constraints. A TBR of 1.17 is achieved for a relatively thin blanket (approx. = 43 cm depth), and consistency with all imposed constraints

Optimization of virtual source parameters in neutron scattering instrumentation

International Nuclear Information System (INIS)

Habicht, K; Skoulatos, M

2012-01-01

We report on phase-space optimizations for neutron scattering instruments employing horizontal focussing crystal optics. Defining a figure of merit for a generic virtual source configuration we identify a set of optimum instrumental parameters. In order to assess the quality of the instrumental configuration we combine an evolutionary optimization algorithm with the analytical Popovici description using multidimensional Gaussian distributions. The optimum phase-space element which needs to be delivered to the virtual source by preceding neutron optics may be obtained using the same algorithm which is of general interest in instrument design.

Logic-based methods for optimization combining optimization and constraint satisfaction

CERN Document Server

Hooker, John

2011-01-01

A pioneering look at the fundamental role of logic in optimization and constraint satisfaction While recent efforts to combine optimization and constraint satisfaction have received considerable attention, little has been said about using logic in optimization as the key to unifying the two fields. Logic-Based Methods for Optimization develops for the first time a comprehensive conceptual framework for integrating optimization and constraint satisfaction, then goes a step further and shows how extending logical inference to optimization allows for more powerful as well as flexible

Adaptive multi-objective Optimization scheme for cognitive radio resource management

KAUST Repository

Alqerm, Ismail; Shihada, Basem

2014-01-01

configuration by exploiting optimization and machine learning techniques. In this paper, we propose an Adaptive Multi-objective Optimization Scheme (AMOS) for cognitive radio resource management to improve spectrum operation and network performance

Stiffened Composite Fuselage Barrel Optimization

Science.gov (United States)

Movva, R. G.; Mittal, A.; Agrawal, K.; Upadhyay, C. S.

2012-07-01

In a typical commercial transport aircraft, Stiffened skin panels and frames contribute around 40% of the fuselage weight. In the current study a stiffened composite fuselage skin panel optimization engine is developed for optimization of the layups of composite panels and stringers using Genetic Algorithm (GA). The skin and stringers of the fuselage section are optimized for the strength and the stability requirements. The selection of the GA parameters considered for the optimization is arrived by performing case studies on selected problems. The optimization engine facilitates in carrying out trade studies for selection of the optimum ply layup and material combination for the configuration being analyzed. The optimization process is applied on a sample model and the results are presented.

Major integration issues in evolving the configuration design space for the Aries-Cs compact stellarator power plant

International Nuclear Information System (INIS)

Raffray, A.R.; Malang, S.; El-Guebaly, L.; Ihli, T.; Najmabadi, F.; Wang, X.

2006-01-01

The Aries-Cs study has been launched with the goal of developing through physics and engineering optimization an attractive power plant concept based on a compact stellarator configuration. The first phase of the study involved scoping out different physics configurations including two and three field period options. The engineering effort during that phase aimed at scoping out maintenance schemes and power core designs best suited to a compact stellarator configuration. This led to a down selection of the most attractive blanket configurations and maintenance schemes for more detailed studies during the second phase of the study. This paper summarizes early results from the second phase of the Aries-Cs study with a particular emphasis on the engineering effort

Numerical optimization of alignment reproducibility for customizable surgical guides.

Science.gov (United States)

Kroes, Thomas; Valstar, Edward; Eisemann, Elmar

2015-10-01

Computer-assisted orthopedic surgery aims at minimizing invasiveness, postoperative pain, and morbidity with computer-assisted preoperative planning and intra-operative guidance techniques, of which camera-based navigation and patient-specific templates (PST) are the most common. PSTs are one-time templates that guide the surgeon initially in cutting slits or drilling holes. This method can be extended to reusable and customizable surgical guides (CSG), which can be adapted to the patients' bone. Determining the right set of CSG input parameters by hand is a challenging task, given the vast amount of input parameter combinations and the complex physical interaction between the PST/CSG and the bone. This paper introduces a novel algorithm to solve the problem of choosing the right set of input parameters. Our approach predicts how well a CSG instance is able to reproduce the planned alignment based on a physical simulation and uses a genetic optimization algorithm to determine optimal configurations. We validate our technique with a prototype of a pin-based CSG and nine rapid prototyped distal femora. The proposed optimization technique has been compared to manual optimization by experts, as well as participants with domain experience. Using the optimization technique, the alignment errors remained within practical boundaries of 1.2 mm translation and [Formula: see text] rotation error. In all cases, the proposed method outperformed manual optimization. Manually optimizing CSG parameters turns out to be a counterintuitive task. Even after training, subjects with and without anatomical background fail in choosing appropriate CSG configurations. Our optimization algorithm ensures that the CSG is configured correctly, and we could demonstrate that the intended alignment of the CSG is accurately reproduced on all tested bone geometries.

VLSI Architecture for Configurable and Low-Complexity Design of Hard-Decision Viterbi Decoding Algorithm

Directory of Open Access Journals (Sweden)

Rachmad Vidya Wicaksana Putra

2016-06-01

Full Text Available Convolutional encoding and data decoding are fundamental processes in convolutional error correction. One of the most popular error correction methods in decoding is the Viterbi algorithm. It is extensively implemented in many digital communication applications. Its VLSI design challenges are about area, speed, power, complexity and configurability. In this research, we specifically propose a VLSI architecture for a configurable and low-complexity design of a hard-decision Viterbi decoding algorithm. The configurable and low-complexity design is achieved by designing a generic VLSI architecture, optimizing each processing element (PE at the logical operation level and designing a conditional adapter. The proposed design can be configured for any predefined number of trace-backs, only by changing the trace-back parameter value. Its computational process only needs N + 2 clock cycles latency, with N is the number of trace-backs. Its configurability function has been proven for N = 8, N = 16, N = 32 and N = 64. Furthermore, the proposed design was synthesized and evaluated in Xilinx and Altera FPGA target boards for area consumption and speed performance.

Multi-Objective Two-Dimensional Truss Optimization by using Genetic Algorithm

Directory of Open Access Journals (Sweden)

Harun Alrasyid

2011-05-01

Full Text Available During last three decade, many mathematical programming methods have been develop for solving optimization problems. However, no single method has been found to be entirely efficient and robust for the wide range of engineering optimization problems. Most design application in civil engineering involve selecting values for a set of design variables that best describe the behavior and performance of the particular problem while satisfying the requirements and specifications imposed by codes of practice. The introduction of Genetic Algorithm (GA into the field of structural optimization has opened new avenues for research because they have been successful applied while traditional methods have failed. GAs is efficient and broadly applicable global search procedure based on stochastic approach which relies on “survival of the fittest” strategy. GAs are search algorithms that are based on the concepts of natural selection and natural genetics. On this research Multi-objective sizing and configuration optimization of the two-dimensional truss has been conducted using a genetic algorithm. Some preliminary runs of the GA were conducted to determine the best combinations of GA parameters such as population size and probability of mutation so as to get better scaling for rest of the runs. Comparing the results from sizing and sizing– configuration optimization, can obtained a significant reduction in the weight and deflection. Sizing–configuration optimization produces lighter weight and small displacement than sizing optimization. The results were obtained by using a GA with relative ease (computationally and these results are very competitive compared to those obtained from other methods of truss optimization.

Optimizing a reconfigurable material via evolutionary computation

Science.gov (United States)

Wilken, Sam; Miskin, Marc Z.; Jaeger, Heinrich M.

2015-08-01

Rapid prototyping by combining evolutionary computation with simulations is becoming a powerful tool for solving complex design problems in materials science. This method of optimization operates in a virtual design space that simulates potential material behaviors and after completion needs to be validated by experiment. However, in principle an evolutionary optimizer can also operate on an actual physical structure or laboratory experiment directly, provided the relevant material parameters can be accessed by the optimizer and information about the material's performance can be updated by direct measurements. Here we provide a proof of concept of such direct, physical optimization by showing how a reconfigurable, highly nonlinear material can be tuned to respond to impact. We report on an entirely computer controlled laboratory experiment in which a 6 ×6 grid of electromagnets creates a magnetic field pattern that tunes the local rigidity of a concentrated suspension of ferrofluid and iron filings. A genetic algorithm is implemented and tasked to find field patterns that minimize the force transmitted through the suspension. Searching within a space of roughly 1010 possible configurations, after testing only 1500 independent trials the algorithm identifies an optimized configuration of layered rigid and compliant regions.

Characteristic Analysis Light Intensity Sensor Based On Plastic Optical Fiber At Various Configuration

Science.gov (United States)

Arifin, A.; Lusiana; Yunus, Muhammad; Dewang, Syamsir

2018-03-01

This research discusses the light intensity sensor based on plastic optical fiber. This light intensity sensor is made of plastic optical fiber consisting of two types, namely which is cladding and without cladding. Plastic optical fiber used multi-mode step-index type made of polymethyl metacrylate (PMMA). The infrared LED emits light into the optical fiber of the plastic and is subsequently received by the phototransistor to be converted to an electric voltage. The sensor configuration is made with three models: straight configuration, U configuration and gamma configuration with cladding and without cladding. The measured light source uses a 30 Watt high power LED with a light intensity of 0 to 10 Klux. The measured light intensity will affect the propagation of light inside the optical fiber sensor. The greater the intensity of the measured light, the greater the output voltage that is read on the computer. The results showed that the best optical fiber sensor characteristics were obtained in U configuration. Sensors with U-configuration without cladding had the best sensitivity and resolution values of 0.0307 volts/Klux and 0.0326 Klux. The advantages of this measuring light intensity based on the plastic optical fiber instrument are simple, easy-to-make operational systems, low cost, high sensitivity and resolution.

Level Set-Based Topology Optimization for the Design of an Electromagnetic Cloak With Ferrite Material

DEFF Research Database (Denmark)

Otomori, Masaki; Yamada, Takayuki; Andkjær, Jacob Anders

2013-01-01

. A level set-based topology optimization method incorporating a fictitious interface energy is used to find optimized configurations of the ferrite material. The numerical results demonstrate that the optimization successfully found an appropriate ferrite configuration that functions as an electromagnetic......This paper presents a structural optimization method for the design of an electromagnetic cloak made of ferrite material. Ferrite materials exhibit a frequency-dependent degree of permeability, due to a magnetic resonance phenomenon that can be altered by changing the magnitude of an externally...

Economic evaluation of flying-qualities design criteria for a transport configured with relaxed static stability

Science.gov (United States)

Sliwa, S. M.

1980-01-01

Direct constrained parameter optimization was used to optimally size a medium range transport for minimum direct operating cost. Several stability and control constraints were varied to study the sensitivity of the configuration to specifying the unaugmented flying qualities of transports designed to take maximum advantage of relaxed static stability augmentation systems. Additionally, a number of handling qualities related design constants were studied with respect to their impact on the design.

HLT configuration management system

CERN Document Server

Daponte, Vincenzo

2015-01-01

The CMS High Level Trigger (HLT) is implemented running a streamlined version of the CMS offline reconstruction software running on thousands of CPUs. The CMS software is written mostly in C++, using Python as its configuration language through an embedded CPython interpreter. The configuration of each process is made up of hundreds of modules, organized in sequences and paths. As an example, the HLT configurations used for 2011 data taking comprised over 2200 different modules, organized in more than 400 independent trigger paths. The complexity of the HLT configurations and the large number of configuration produced require the design of a suitable data management system. The present work describes the designed solution to manage the considerable number of configurations developed and to assist the editing of new configurations. The system is required to be remotely accessible and OS-independent as well as easly maintainable easy to use. To meet these requirements a three-layers architecture has been choose...

Solutions on high-resolution multiple configuration system sensors

Science.gov (United States)

Liu, Hua; Ding, Quanxin; Guo, Chunjie; Zhou, Liwei

2014-11-01

For aim to achieve an improved resolution in modern image domain, a method of continuous zoom multiple configuration, with a core optics is attempt to establish model by novel principle on energy transfer and high accuracy localization, by which the system resolution can be improved with a level in nano meters. A comparative study on traditional vs modern methods can demonstrate that the dialectical relationship and their balance is important, among Merit function, Optimization algorithms and Model parameterization. The effect of system evaluated criterion that MTF, REA, RMS etc. can support our arguments qualitatively.

Configuration by Modularisation

DEFF Research Database (Denmark)

Riitahuhta, Asko; Andreasen, Mogens Myrup

1998-01-01

Globally operating companies have realized that locally customized products and services are today the prerequisite for the success. The capability or the paradigm to act locally in global markets is called Mass Customization [Victor 1997]. The prerequisite for Mass Customization is Configuration...... Management and i Configuration Management the most important means is Modularisation.The goal of this paper is to show Configuration Management as a contribution to the Mass Customisation and Modularisation as a contribution to the industrialisation of the design area [Andreasen 1997]. A basic model...... for the creation of a structured product family is presented and examples are given. The concepts of a novel Dynamic Modularisation method, Metrics for Modularisation and Design for Configurability are presented....

Reference frame for Product Configuration

DEFF Research Database (Denmark)

Ladeby, Klaes Rohde; Oddsson, Gudmundur Valur

2011-01-01

a reference frame for configuration that permits 1) a more precise understanding of a configuration system, 2) a understanding of how the configuration system relate to other systems, and 3) a definition of the basic concepts in configuration. The total configuration system, together with the definition...

Ground Receiving Station Reference Pair Selection Technique for a Minimum Configuration 3D Emitter Position Estimation Multilateration System

Directory of Open Access Journals (Sweden)

Abdulmalik Shehu Yaro

2017-01-01

Full Text Available Multilateration estimates aircraft position using the Time Difference Of Arrival (TDOA with a lateration algorithm. The Position Estimation (PE accuracy of the lateration algorithm depends on several factors which are the TDOA estimation error, the lateration algorithm approach, the number of deployed GRSs and the selection of the GRS reference used for the PE process. Using the minimum number of GRSs for 3D emitter PE, a technique based on the condition number calculation is proposed to select the suitable GRS reference pair for improving the accuracy of the PE using the lateration algorithm. Validation of the proposed technique was performed with the GRSs in the square and triangular GRS configuration. For the selected emitter positions, the result shows that the proposed technique can be used to select the suitable GRS reference pair for the PE process. A unity condition number is achieved for GRS pair most suitable for the PE process. Monte Carlo simulation result, in comparison with the fixed GRS reference pair lateration algorithm, shows a reduction in PE error of at least 70% for both GRS in the square and triangular configuration.

An air-based corrugated cavity-receiver for solar parabolic trough concentrators

International Nuclear Information System (INIS)

Bader, Roman; Pedretti, Andrea; Barbato, Maurizio; Steinfeld, Aldo

2015-01-01

Highlights: • We analyze a novel tubular cavity-receiver for solar parabolic trough collectors. • Four-fold solar concentration ratio is reached compared to conventional receivers. • Efficient operation at up to 500 °C is possible. • The pumping power requirement is found to be acceptably low. - Abstract: A tubular cavity-receiver that uses air as the heat transfer fluid is evaluated numerically using a validated heat transfer model. The receiver is designed for use on a large-span (9 m net concentrator aperture width) solar parabolic trough concentrator. Through the combination of a parabolic primary concentrator with a nonimaging secondary concentrator, the collector reaches a solar concentration ratio of 97.5. Four different receiver configurations are considered, with smooth or V-corrugated absorber tube and single- or double-glazed aperture window. The collector’s performance is characterized by its optical efficiency and heat loss. The optical efficiency is determined with the Monte Carlo ray-tracing method. Radiative heat exchange inside the receiver is calculated with the net radiation method. The 2D steady-state energy equation, which couples conductive, convective, and radiative heat transfer, is solved for the solid domains of the receiver cross-section, using finite-volume techniques. Simulations for Sevilla/Spain at the summer solstice at solar noon (direct normal solar irradiance: 847 W m −2 , solar incidence angle: 13.9°) yield collector efficiencies between 60% and 65% at a heat transfer fluid temperature of 125 °C and between 37% and 42% at 500 °C, depending on the receiver configuration. The optical losses amount to more than 30% of the incident solar radiation and constitute the largest source of energy loss. For a 200 m long collector module operated between 300 and 500 °C, the isentropic pumping power required to pump the HTF through the receiver is between 11 and 17 kW

Drift wave instability and turbulence in advanced stellarator configurations

International Nuclear Information System (INIS)

Kendl, A.

2001-08-01

In the following chapter, an overview and references on the physics and geometry of helical advanced stellarators is given. On the basis of this configuration, the influence of magnetic field geometry is then discussed in a basic model of drift-Alfven wave turbulence which contains the necessary physics that applies to the plasma edge. By means of linear models, core physics in the form of ITG and dissipative trapped electron modes is further included in our survey. These models are, of course, by far not comprehensive in order to cover the complex physics of plasma turbulence in three-dimensional fusion devices, where a large range of parameter and mode regimes is present. Optimization criteria for a possible systematic minimization of turbulent transport in Helias configurations therefore still have to be regarded as tentative. The results presented here should, however, encourage for more detailed future computations. (orig.)

System performance optimization

International Nuclear Information System (INIS)

Bednarz, R.J.

1978-01-01

The System Performance Optimization has become an important and difficult field for large scientific computer centres. Important because the centres must satisfy increasing user demands at the lowest possible cost. Difficult because the System Performance Optimization requires a deep understanding of hardware, software and workload. The optimization is a dynamic process depending on the changes in hardware configuration, current level of the operating system and user generated workload. With the increasing complication of the computer system and software, the field for the optimization manoeuvres broadens. The hardware of two manufacturers IBM and CDC is discussed. Four IBM and two CDC operating systems are described. The description concentrates on the organization of the operating systems, the job scheduling and I/O handling. The performance definitions, workload specification and tools for the system stimulation are given. The measurement tools for the System Performance Optimization are described. The results of the measurement and various methods used for the operating system tuning are discussed. (Auth.)

Software configuration management

CERN Document Server

Keyes, Jessica

2004-01-01

Software Configuration Management discusses the framework from a standards viewpoint, using the original DoD MIL-STD-973 and EIA-649 standards to describe the elements of configuration management within a software engineering perspective. Divided into two parts, the first section is composed of 14 chapters that explain every facet of configuration management related to software engineering. The second section consists of 25 appendices that contain many valuable real world CM templates.

Benefits Assessment for Single-Airport Tactical Runway Configuration Management Tool (TRCM)

Science.gov (United States)

Oseguera-Lohr, Rosa; Phojanamonogkolkij, Nipa; Lohr, Gary W.

2015-01-01

The System-Oriented Runway Management (SORM) concept was developed as part of the Airspace Systems Program (ASP) Concepts and Technology Development (CTD) Project, and is composed of two basic capabilities: Runway Configuration Management (RCM), and Combined Arrival/Departure Runway Scheduling (CADRS). RCM is the process of designating active runways, monitoring the active runway configuration for suitability given existing factors, and predicting future configuration changes; CADRS is the process of distributing arrivals and departures across active runways based on local airport and National Airspace System (NAS) goals. The central component in the SORM concept is a tool for taking into account all the various factors and producing a recommendation for what would be the optimal runway configuration, runway use strategy, and aircraft sequence, considering as many of the relevant factors required in making this type of decision, and user preferences, if feasible. Three separate tools were initially envisioned for this research area, corresponding to the time scale in which they would operate: Strategic RCM (SRCM), with a planning horizon on the order of several hours, Tactical RCM (TRCM), with a planning horizon on the order of 90 minutes, and CADRS, with a planning horizon on the order of 15-30 minutes[1]. Algorithm development was initiated in all three of these areas, but the most fully developed to date is the TRCM algorithm. Earlier studies took a high-level approach to benefits, estimating aggregate benefits across most of the major airports in the National Airspace Systems (NAS), for both RCM and CADRS [2]. Other studies estimated the benefit of RCM and CADRS using various methods of re-sequencing arrivals to reduce delays3,4, or better balancing of arrival fixes5,6. Additional studies looked at different methods for performing the optimization involved in selecting the best Runway Configuration Plan (RCP) to use7-10. Most of these previous studies were high

An optimal design problem in wave propagation

DEFF Research Database (Denmark)

Bellido, J.C.; Donoso, Alberto

2007-01-01

of finding the best distributions of the two initial materials in a rod in order to minimize the vibration energy in the structure under periodic loading of driving frequency Omega. We comment on relaxation and optimality conditions, and perform numerical simulations of the optimal configurations. We prove...... also the existence of classical solutions in certain cases....

The application of neural networks for optimization of the configuration of fuel assemblies in PWR reactors

International Nuclear Information System (INIS)

Sadighi, M.; Setayeshi, S.; Salehi, A.A.

2002-01-01

This paper presents a new method to solve the problem of finding the best configuration of fuel assemblies in a PWR (Pressurized Water Reactor) core. Finding an optimum solution requires a huge amount of calculations in classical methods. It has been shown that the application of continuous Hop field neural network accompanied by the Simulated Annealing method to this problem not only reduces the volume of the calculations, but also guarantees finding the best solution. In this study flattening of neutron flux inside the reactor core of Brusher NPP is considered as an objective function. The result shows the optimum core configuration which is in agreement with the pattern proposed by the designer

Advanced Signal Processing for MIMO-OFDM Receivers

DEFF Research Database (Denmark)

Manchón, Carles Navarro

This thesis deals with a wide range of topics within the research area of advanced baseband receiver design for wireless communication systems. In particular, the work focuses on signal processing algorithms for receivers in multiple-input multiple-output (MIMO) orthogonal frequency-division mult......This thesis deals with a wide range of topics within the research area of advanced baseband receiver design for wireless communication systems. In particular, the work focuses on signal processing algorithms for receivers in multiple-input multiple-output (MIMO) orthogonal frequency...... the structure of the receiver with the hope that the resulting heuristic architecture will exhibit the desired behavior and performance. On the other hand, one can employ analytical frameworks to pose the problem as the optimization of a global objective function subject to certain constraints. This work...

[Application of simulated annealing method and neural network on optimizing soil sampling schemes based on road distribution].

Science.gov (United States)

Han, Zong-wei; Huang, Wei; Luo, Yun; Zhang, Chun-di; Qi, Da-cheng

2015-03-01

Taking the soil organic matter in eastern Zhongxiang County, Hubei Province, as a research object, thirteen sample sets from different regions were arranged surrounding the road network, the spatial configuration of which was optimized by the simulated annealing approach. The topographic factors of these thirteen sample sets, including slope, plane curvature, profile curvature, topographic wetness index, stream power index and sediment transport index, were extracted by the terrain analysis. Based on the results of optimization, a multiple linear regression model with topographic factors as independent variables was built. At the same time, a multilayer perception model on the basis of neural network approach was implemented. The comparison between these two models was carried out then. The results revealed that the proposed approach was practicable in optimizing soil sampling scheme. The optimal configuration was capable of gaining soil-landscape knowledge exactly, and the accuracy of optimal configuration was better than that of original samples. This study designed a sampling configuration to study the soil attribute distribution by referring to the spatial layout of road network, historical samples, and digital elevation data, which provided an effective means as well as a theoretical basis for determining the sampling configuration and displaying spatial distribution of soil organic matter with low cost and high efficiency.

Redundant interferometric calibration as a complex optimization problem

Science.gov (United States)

Grobler, T. L.; Bernardi, G.; Kenyon, J. S.; Parsons, A. R.; Smirnov, O. M.

2018-05-01

Observations of the redshifted 21 cm line from the epoch of reionization have recently motivated the construction of low-frequency radio arrays with highly redundant configurations. These configurations provide an alternative calibration strategy - `redundant calibration' - and boost sensitivity on specific spatial scales. In this paper, we formulate calibration of redundant interferometric arrays as a complex optimization problem. We solve this optimization problem via the Levenberg-Marquardt algorithm. This calibration approach is more robust to initial conditions than current algorithms and, by leveraging an approximate matrix inversion, allows for further optimization and an efficient implementation (`redundant STEFCAL'). We also investigated using the preconditioned conjugate gradient method as an alternative to the approximate matrix inverse, but found that its computational performance is not competitive with respect to `redundant STEFCAL'. The efficient implementation of this new algorithm is made publicly available.

Full load synthesis/design optimization of a hybrid SOFC-GT power plant

International Nuclear Information System (INIS)

Calise, F.; Dentice d' Accadia, M.; Vanoli, L.; Spakovsky, Michael R. von

2007-01-01

In this paper, the optimization of a hybrid solid oxide fuel cell-gas turbine (SOFC-GT) power plant is presented. The plant layout is based on an internal reforming SOFC stack; it also consists of a radial gas turbine, centrifugal compressors and plate-fin heat exchangers. In the first part of the paper, the bulk-flow model used to simulate the plant is presented. In the second part, a thermoeconomic model is developed by introducing capital cost functions. The whole plant is first simulated for a fixed configuration of the most important synthesis/design (S/D) parameters in order to establish a reference design configuration. Next a S/D optimization of the plant is carried out using a traditional single-level approach, based on a genetic algorithm. The optimization determined a set of S/D decision variable values with a capital cost significantly lower than that of the reference design, even though the net electrical efficiency for the optimal configuration was very close to that of the initial one. Furthermore, the optimization procedure dramatically reduced the SOFC active area and the compact heat exchanger areas

Neoclassical transport optimization of LHD

International Nuclear Information System (INIS)

Murakami, S.; Yamada, H.; Watanabe, K.Y.; Wakasa, A.; Maassberg, H.; Beidler, C.D.

2002-06-01

Neoclassical transport is studied for LHD configurations in which the magnetic axis has been shifted radially by determining the mono-energetic transport coefficient and the effective helical ripple. With respect to the transport in the long mean free path collisionality region - the so called 1/ν transport -, the optimum configuration is found when the magnetic axis has a major radius of 3.53m, which is 0.22m inward shifted from the standard'' configuration of LHD. In the optimized case, the effective helical ripple is very small, remaining below 2% inside 4/5 of the plasma radius. This indicates that a strong inward shift of the magnetic axis in the LHD can diminish the neoclassical transport to a level typical of so-called advanced stellarators''. (author)

Multi-objective optimization of an underwater compressed air energy storage system using genetic algorithm

International Nuclear Information System (INIS)

Cheung, Brian C.; Carriveau, Rupp; Ting, David S.K.

2014-01-01

This paper presents the findings from a multi-objective genetic algorithm optimization study on the design parameters of an underwater compressed air energy storage system (UWCAES). A 4 MWh UWCAES system was numerically simulated and its energy, exergy, and exergoeconomics were analysed. Optimal system configurations were determined that maximized the UWCAES system round-trip efficiency and operating profit, and minimized the cost rate of exergy destruction and capital expenditures. The optimal solutions obtained from the multi-objective optimization model formed a Pareto-optimal front, and a single preferred solution was selected using the pseudo-weight vector multi-criteria decision making approach. A sensitivity analysis was performed on interest rates to gauge its impact on preferred system designs. Results showed similar preferred system designs for all interest rates in the studied range. The round-trip efficiency and operating profit of the preferred system designs were approximately 68.5% and $53.5/cycle, respectively. The cost rate of the system increased with interest rates. - Highlights: • UWCAES system configurations were developed using multi-objective optimization. • System was optimized for energy efficiency, exergy, and exergoeconomics • Pareto-optimal solution surfaces were developed at different interest rates. • Similar preferred system configurations were found at all interest rates studied

Effects of work zone configurations and traffic density on performance variables and subjective workload.

Science.gov (United States)

Shakouri, Mahmoud; Ikuma, Laura H; Aghazadeh, Fereydoun; Punniaraj, Karthy; Ishak, Sherif

2014-10-01

This paper investigates the effect of changing work zone configurations and traffic density on performance variables and subjective workload. Data regarding travel time, average speed, maximum percent braking force and location of lane changes were collected by using a full size driving simulator. The NASA-TLX was used to measure self-reported workload ratings during the driving task. Conventional lane merge (CLM) and joint lane merge (JLM) were modeled in a driving simulator, and thirty participants (seven female and 23 male), navigated through the two configurations with two levels of traffic density. The mean maximum braking forces was 34% lower in the JLM configuration, and drivers going through the JLM configuration remained in the closed lane longer. However, no significant differences in speed were found between the two merge configurations. The analysis of self-reported workload ratings show that participants reported 15.3% lower total workload when driving through the JLM. In conclusion, the implemented changes in the JLM make it a more favorable merge configuration in both high and low traffic densities in terms of optimizing traffic flow by increasing the time and distance cars use both lanes, and in terms of improving safety due to lower braking forces and lower reported workload. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ferroelectric materials for piezoelectric actuators by optimal design

International Nuclear Information System (INIS)

Jayachandran, K.P.; Guedes, J.M.; Rodrigues, H.C.

2011-01-01

Research highlights: → Microstructure optimization of ferroelectric materials by stochastic optimization. → Polycrystalline ferroelectrics possess better piezo actuation than single crystals. → Randomness of the grain orientations would enhance the overall piezoelectricity. - Abstract: Optimization methods provide a systematic means of designing heterogeneous materials with tailored properties and microstructures focussing on a specific objective. An optimization procedure incorporating a continuum modeling is used in this work to identify the ideal orientation distribution of ferroelectrics (FEs) for application in piezoelectric actuators. Piezoelectric actuation is dictated primarily by the piezoelectric strain coefficients d iμ . Crystallographic orientation is inextricably related to the piezoelectric properties of FEs. This suggests that piezoelectric properties can be tailored by a proper choice of the parameters which control the orientation distribution. Nevertheless, this choice is complicated and it is impossible to analyze all possible combinations of the distribution parameters or the angles themselves. Stochastic optimization combined with a generalized Monte Carlo scheme is used to optimize the objective functions, the effective piezoelectric coefficients d 31 and d 15 . The procedure is applied to heterogeneous, polycrystalline, FE ceramics which are essentially an aggregate of variously oriented grains (crystallites). Global piezoelectric properties are calculated using the homogenization method at each grain configuration chosen by the optimization algorithm. Optimal design variables and microstructure that would generate polycrystalline configurations that multiply the macroscopic piezoelectricity are identified.

MICROCONTROLLER PIN CONFIGURATION TOOL

OpenAIRE

Bhaskar Joshi; F. Mohammed Rizwan; Dr. Rajashree Shettar

2012-01-01

Configuring the micro controller with large number of pins is tedious. Latest Infine on microcontroller contains more than 200 pins and each pin has classes of signals. Therefore the complexity of the microcontroller is growing. It evolves looking into thousands of pages of user manual. For a user it will take days to configure the microcontroller with the peripherals. We need an automated tool to configure the microcontroller so that the user can configure the microcontroller without having ...

Sensitivity analysis of nacelle lidar free stream wind speed measurements to wind-induction reconstruction model and lidar range configuration

DEFF Research Database (Denmark)

Svensson, Elin; Borraccino, Antoine; Meyer Forsting, Alexander Raul

The sensitivity of nacelle lidar wind speed measurements to wind-induction models and lidar range configurations is studied using experimental data from the Nørrekær Enge (NKE) measurement campaign and simulated lidar data from Reynold-Averaged Navier Stokes (RANS) aerodynamic computational fluid...... the ZDM was configured to measure at five distances. From the configured distances, a large number of range configurations were created and systematically tested to determine the sensitivity of the reconstructed wind speeds to the number of ranges, minimum range and maximum range in the range......) of the fitting residuals. The results demonstrate that it is not possible to use RANS CFD simulated lidar data to determine optimal range configurations for real-time nacelle lidars due to their perfect (unrealistic) representation of the simulated flow field. The recommended range configurations are therefore...

Optimization of aerodynamic efficiency for twist morphing MAV wing

Directory of Open Access Journals (Sweden)

N.I. Ismail

2014-06-01

Full Text Available Twist morphing (TM is a practical control technique in micro air vehicle (MAV flight. However, TM wing has a lower aerodynamic efficiency (CL/CD compared to membrane and rigid wing. This is due to massive drag penalty created on TM wing, which had overwhelmed the successive increase in its lift generation. Therefore, further CL/CDmax optimization on TM wing is needed to obtain the optimal condition for the morphing wing configuration. In this paper, two-way fluid–structure interaction (FSI simulation and wind tunnel testing method are used to solve and study the basic wing aerodynamic performance over (non-optimal TM, membrane and rigid wings. Then, a multifidelity data metamodel based design optimization (MBDO process is adopted based on the Ansys-DesignXplorer frameworks. In the adaptive MBDO process, Kriging metamodel is used to construct the final multifidelity CL/CD responses by utilizing 23 multi-fidelity sample points from the FSI simulation and experimental data. The optimization results show that the optimal TM wing configuration is able to produce better CL/CDmax magnitude by at least 2% than the non-optimal TM wings. The flow structure formation reveals that low TV strength on the optimal TM wing induces low CD generation which in turn improves its overall CL/CDmax performance.

Particle Swarm Optimization for Outdoor Lighting Design

Directory of Open Access Journals (Sweden)

Ana Castillo-Martinez

2017-01-01

Full Text Available Outdoor lighting is an essential service for modern life. However, the high influence of this type of facility on energy consumption makes it necessary to take extra care in the design phase. Therefore, this manuscript describes an algorithm to help light designers to get, in an easy way, the best configuration parameters and to improve energy efficiency, while ensuring a minimum level of overall uniformity. To make this possible, we used a particle swarm optimization (PSO algorithm. These algorithms are well established, and are simple and effective to solve optimization problems. To take into account the most influential parameters on lighting and energy efficiency, 500 simulations were performed using DIALux software (4.10.0.2, DIAL, Ludenscheid, Germany. Next, the relation between these parameters was studied using to data mining software. Subsequently, we conducted two experiments for setting parameters that enabled the best configuration algorithm in order to improve efficiency in the proposed process optimization.

Multi-fidelity optimization of horizontal axis wind turbines

DEFF Research Database (Denmark)

McWilliam, Michael; Zahle, Frederik; Pavese, Christian

2017-01-01

This paper is concerned with the numerical design optimization of wind turbines. Many examples of wind turbine design optimization in literature rely on simplified analysis in some form. This may lead to sub-optimal design, because the optimizer does not see the full fidelity of the problem....... Finally, AMMF was used in full aero-elastic wind turbine rotor design optimization problem based on the DTU 10 MW reference wind turbine design. Mixed results were achieved for the final study and further work is needed to find the best configuration for AMMF....

Gas/liquid flow configurations

International Nuclear Information System (INIS)

Bonin, Jacques; Fitremann, J.-M.

1978-01-01

Prediction of flow configurations (morphology) for gas/liquid or liquid/vapour mixtures is an important industrial problem which is not yet fully understood. The ''Flow Configurations'' Seminar of Societe Hydrotechnique de France has framed recommendations for investigation of potential industrial applications for flow configurations [fr

Is there an additional benefit of serial NT-proBNP measurements in patients with stable chronic heart failure receiving individually optimized therapy?

Science.gov (United States)

Franke, Jennifer; Frankenstein, Lutz; Schellberg, Dieter; Bajrovic, Amer; Wolter, Jan Sebastian; Ehlermann, Philipp; Doesch, Andreas O; Nelles, Manfred; Katus, Hugo A; Zugck, Christian

2011-12-01

The role of serial NT-proBNP measurements in patients suffering from chronic systolic heart failure (CHF) who already receive individually optimized pharmacotherapy is still unresolved. NT-proBNP was assessed at baseline and at 6 months follow-up in 504 stable CHF patients treated with individually optimized pharmacotherapy. After assessment of clinical stability at 6 months, patients were followed up for at least 1 year. The combined primary endpoint was defined as death, hospitalization due to cardiac reasons or heart transplantation in 1-year follow-up. We stratified our patients according to two principles: first, a percent change of value (CV) between the first and second measurement of NT-proBNP and secondly, the transformed logarithm of NT-proBNP measured at 6 months. During the follow-up period of 1 year, 50 patients (9.9%) reached the combined primary endpoint. Stratification according to percentage CV was less accurate in predicting endpoint-free survival compared to a classification in categories of lnNT-proBNP measured at 6 months (ROC AUC = 0.615; 95% CI 0.525-0.70 vs. ROC AUC = 0.790; 95% CI 0.721-0.856, respectively). When entered into proportional hazard regression analysis, lnNT-proBNP measured at 6 months remained an independent predictor of the combined primary endpoint with an associated HR of 2.53 (95% CI 1.385-4.280). To date, this is the largest analysis of serial NT-proBNP measurements in patients with CHF receiving individually optimized medical therapy. These data suggest that a single NT-proBNP measurement after 6 months in stable clinical conditions may have higher predictive value than stratification of change in serial measurements.

A configural dominant account of contextual cueing: Configural cues are stronger than colour cues.

Science.gov (United States)

Kunar, Melina A; John, Rebecca; Sweetman, Hollie

2014-01-01

Previous work has shown that reaction times to find a target in displays that have been repeated are faster than those for displays that have never been seen before. This learning effect, termed "contextual cueing" (CC), has been shown using contexts such as the configuration of the distractors in the display and the background colour. However, it is not clear how these two contexts interact to facilitate search. We investigated this here by comparing the strengths of these two cues when they appeared together. In Experiment 1, participants searched for a target that was cued by both colour and distractor configural cues, compared with when the target was only predicted by configural information. The results showed that the addition of a colour cue did not increase contextual cueing. In Experiment 2, participants searched for a target that was cued by both colour and distractor configuration compared with when the target was only cued by colour. The results showed that adding a predictive configural cue led to a stronger CC benefit. Experiments 3 and 4 tested the disruptive effects of removing either a learned colour cue or a learned configural cue and whether there was cue competition when colour and configural cues were presented together. Removing the configural cue was more disruptive to CC than removing colour, and configural learning was shown to overshadow the learning of colour cues. The data support a configural dominant account of CC, where configural cues act as the stronger cue in comparison to colour when they are presented together.

Design and development of an ultrasonic pulser-receiver unit for non-destructive testing of materials

International Nuclear Information System (INIS)

Patankar, V.H.; Joshi, V.M.

2002-11-01

The pulser/receiver constitutes the most vital part of an ultrasonic flaw detector or an ultrasonic imaging system used for inspection of materials. The ultrasonic properties of the material and resolution requirements govern the choice of the frequency of ultrasound that can be optimally used. The pulser/receiver in turn decides the efficiency of excitation of the transducer and the overall signal to noise ratio of the system for best sensitivity and resolution. A variety of pulsers are used in the ultrasonic instruments employed for materials inspection. This report describes a square wave type of an ultrasonic pulser-receiver unit developed at Ultrasonic Instrumentation Section, Electronics Division, BARC. It has been primarily designed for excitation of the transducer that is used with a multi-channel ultrasonic imaging system ULTIMA 100M targeted for inspection of SS403 billets, which are in turn used as the base material for fabrication of end fittings for coolant channels of pressurized heavy water nuclear reactors (PHWRs). The design of the pulser is based upon very fast MOSFETs, configured as electronic switches. The pulser is operated with a linear bipolar H.V. supply (+/- 500V max.). The receiver provides a 60 dB gain with a -3 dB BW of 40 MHz. This pulser/receiver unit has been successfully interfaced with a 4 channel ULTIMA 100 M4 multichannel ultrasonic C-scan imaging system, also designed and developed by the authors at Ultrasonic Instrumentation Section (Electronics Division, BARC) and supplied to Centre for Design and Manufacturer - CDM, BARC. This system is being regularly used in C-scan imaging mode for volumetric inspection of SS403 billets for end fittings of 500 MWe PHWRs. (author)

ZnO film deposition by DC magnetron sputtering: Effect of target configuration on the film properties

Energy Technology Data Exchange (ETDEWEB)

Arakelova, E.; Khachatryan, A.; Kteyan, A.; Avjyan, K.; Grigoryan, S.

2016-08-01

Ballistic transport model for target-to-substrate atom transfer during magnetron sputter deposition was used to develop zinc target (cathode) configuration that enabled growth of uniform zinc oxide films on extensive surfaces and provided reproducibility of films characteristics irrespective of the cathode wear-out. The advantage of the developed target configuration for high-quality ZnO film deposition was observed in the sputtering pressure range of 5− 50 mTorr, and in the range of cathode-to-substrate distances 7–20 cm. Characteristics of the deposited films were demonstrated by using X-ray diffraction analysis, as well as optical and electrical measurements. - Highlights: • Change of target configuration for optimization of magnetron sputtering deposition is proposed. • Improvement of ZnO film properties due to use of this target is demonstrated. • This configuration provided reproducibility of the deposited films properties.

Straight configuration saphenous vein transposition to popliteal artery for vascular access.

Science.gov (United States)

Caco, Gentian; Golemi, Dhurata; Likaj, Eriola

2017-03-21

The saphenous vein is commonly used as a vascular graft in peripheral artery surgery but rarely used for vascular access. The literature on straight configuration saphenous vein transposition to the popliteal artery is scarce. Here we present two cases of straight configuration saphenous vein transposition to the popliteal artery for vascular access, the surgical technique and respective follow-up. Two young men, aged 29 and 36 years, were chosen for lower-limb vascular access for hemodialysis. The first patient was paraplegic since birth. He used his arms to move so upper extremity vascular access was avoided. The second patient presented with an infected upper extremity arteriovenous graft (AVG) and after multiple closed AVFs he had no more available arm veins. Both patients received autologous lower extremity straight configuration saphenous vein transpositions to the popliteal artery under spinal anesthesia in May and October 2012, respectively. Cannulation of the fistula was allowed after one month. There were no early complications. Slight swelling on the leg appeared in one of the patients. Both fistulas were still functional after 36 and 32 months, respectively. The straight configuration saphenous vein transposition to popliteal artery is simple to perform, offers a long and straight segment for cannulation and may be a suitable autologous vascular access in selected patients.

Molecular Spectroscopy With a Compact 557-GHz Heterodyne Receiver

DEFF Research Database (Denmark)

Neumaier, Philipp F.-X.; Richter, Heiko; Stake, Jan

2014-01-01

We report on a heterodyne terahertz spectrometer based on a fully integrated 557-GHz receiver and a digital fast Fourier transform spectrometer. The receiver consists of a chain of multipliers and power amplifiers, followed by a heterostructure barrier varactor tripler that subharmonically pumps...... a membrane GaAs Schottky diode mixer. All sub-components are newly developed and optimized with regard to the overall receiver performance such as noise temperature, power consumption, weight and physical size. The receiver works at room temperature, has a double sideband noise temperature as low as 2000 K...

Configuration management at NEK

International Nuclear Information System (INIS)

Podhraski, M.

1999-01-01

Configuration Management (CM) objectives at NEK are to ensure consistency between Design Requirements, Physical Plant Configuration and Configuration Information. Software applications, supporting Design Change, Work Control and Document Control Processes, are integrated in one module-oriented Management Information System (MIS). Master Equipment Component List (MECL) database is central MIS module. Through a combination of centralized database and process migrated activities it is ensured that the CM principles and requirements (accurate, current design data matching plant's physical configuration while complying to applicable requirements), are followed and fulfilled.(author)

Clinical implementation of stereotaxic brain implant optimization

International Nuclear Information System (INIS)

Rosenow, U.F.; Wojcicka, J.B.

1991-01-01

This optimization method for stereotaxic brain implants is based on seed/strand configurations of the basic type developed for the National Cancer Institute (NCI) atlas of regular brain implants. Irregular target volume shapes are determined from delineation in a stack of contrast enhanced computed tomography scans. The neurosurgeon may then select up to ten directions, or entry points, of surgical approach of which the program finds the optimal one under the criterion of smallest target volume diameter. Target volume cross sections are then reconstructed in 5-mm-spaced planes perpendicular to the implantation direction defined by the entry point and the target volume center. This information is used to define a closed line in an implant cross section along which peripheral seed strands are positioned and which has now an irregular shape. Optimization points are defined opposite peripheral seeds on the target volume surface to which the treatment dose rate is prescribed. Three different optimization algorithms are available: linear least-squares programming, quadratic programming with constraints, and a simplex method. The optimization routine is implemented into a commercial treatment planning system. It generates coordinate and source strength information of the optimized seed configurations for further dose rate distribution calculation with the treatment planning system, and also the coordinate settings for the stereotaxic Brown-Roberts-Wells (BRW) implantation device

Optimizing a physical security configuration using a highly detailed simulation model

NARCIS (Netherlands)

Marechal, T.M.A.; Smith, A.E.; Ustun, V.; Smith, J.S.; Lefeber, A.A.J.; Badiru, A.B.; Thomas, M.U.

2009-01-01

This research is focused on using a highly detailed simulation model to create a physical security system to prevent intrusions in a building. Security consists of guards and security cameras. The problem is represented as a binary optimization problem. A new heuristic is proposed to do the security

Design Optimization of Vena Cava Filters: An application to dual filtration devices

Energy Technology Data Exchange (ETDEWEB)

Singer, M A; Wang, S L; Diachin, D P

2009-12-03

Pulmonary embolism (PE) is a significant medical problem that results in over 300,000 fatalities per year. A common preventative treatment for PE is the insertion of a metallic filter into the inferior vena cava that traps thrombi before they reach the lungs. The goal of this work is to use methods of mathematical modeling and design optimization to determine the configuration of trapped thrombi that minimizes the hemodynamic disruption. The resulting configuration has implications for constructing an optimally designed vena cava filter. Computational fluid dynamics is coupled with a nonlinear optimization algorithm to determine the optimal configuration of trapped model thrombus in the inferior vena cava. The location and shape of the thrombus are parameterized, and an objective function, based on wall shear stresses, determines the worthiness of a given configuration. The methods are fully automated and demonstrate the capabilities of a design optimization framework that is broadly applicable. Changes to thrombus location and shape alter the velocity contours and wall shear stress profiles significantly. For vena cava filters that trap two thrombi simultaneously, the undesirable flow dynamics past one thrombus can be mitigated by leveraging the flow past the other thrombus. Streamlining the shape of thrombus trapped along the cava wall reduces the disruption to the flow, but increases the area exposed to abnormal wall shear stress. Computer-based design optimization is a useful tool for developing vena cava filters. Characterizing and parameterizing the design requirements and constraints is essential for constructing devices that address clinical complications. In addition, formulating a well-defined objective function that quantifies clinical risks and benefits is needed for designing devices that are clinically viable.

Effectiveness of noncoplanar IMRT planning using a parallelized multiresolution beam angle optimization method for paranasal sinus carcinoma

International Nuclear Information System (INIS)

Wang Xiaochun; Zhang Xiaodong; Dong Lei; Liu, Helen; Gillin, Michael; Ahamad, Anesa; Ang Kian; Mohan, Radhe

2005-01-01

Purpose: To determine the effectiveness of noncoplanar beam configurations and the benefit of plans using fewer but optimally placed beams designed by a parallelized multiple-resolution beam angle optimization (PMBAO) approach. Methods and Materials: The PMBAO approach uses a combination of coplanar and noncoplanar beam configurations for intensity-modulated radiation therapy (IMRT) treatment planning of paranasal sinus cancers. A smaller number of beams (e.g. 3) are first used to explore the solution space to determine the best and worst beam directions. The results of this exploration are then used as a starting point for determining an optimum beam orientation configuration with more beams (e.g. 5). This process is parallelized using a message passing interface, which greatly reduces the overall computation time for routine clinical practice. To test this approach, treatment for 10 patients with paranasal sinus cancer was planned using a total of 5 beams from a pool of 46 possible beam angles. The PMBAO treatment plans were also compared with IMRT plans designed using 9 equally spaced coplanar beams, which is the standard approach in our clinic. Plans with these two different beam configurations were compared with respect to dose conformity, dose heterogeneity, dose-volume histograms, and doses to organs at risk (i.e., eyes, optic nerve, optic chiasm, and brain). Results: The noncoplanar beam configuration was superior in most paranasal sinus carcinoma cases. The target dose homogeneity was better using a PMBAO 5-beam configuration. However, the dose conformity using PMBAO was not improved and was case dependent. Compared with the 9-beam configuration, the PMBAO configuration significantly reduced the mean dose to the eyes and optic nerves and the maximum dose to the contralateral optical path (e.g. the contralateral eye and optic nerve). The maximum dose to the ipsilateral eye and optic nerve was also lower using the PMBAO configuration than using the 9-beam

A fast inverse treatment planning strategy facilitating optimized catheter selection in image-guided high-dose-rate interstitial gynecologic brachytherapy.

Science.gov (United States)

Guthier, Christian V; Damato, Antonio L; Hesser, Juergen W; Viswanathan, Akila N; Cormack, Robert A

2017-12-01

Interstitial high-dose rate (HDR) brachytherapy is an important therapeutic strategy for the treatment of locally advanced gynecologic (GYN) cancers. The outcome of this therapy is determined by the quality of dose distribution achieved. This paper focuses on a novel yet simple heuristic for catheter selection for GYN HDR brachytherapy and their comparison against state of the art optimization strategies. The proposed technique is intended to act as a decision-supporting tool to select a favorable needle configuration. The presented heuristic for catheter optimization is based on a shrinkage-type algorithm (SACO). It is compared against state of the art planning in a retrospective study of 20 patients who previously received image-guided interstitial HDR brachytherapy using a Syed Neblett template. From those plans, template orientation and position are estimated via a rigid registration of the template with the actual catheter trajectories. All potential straight trajectories intersecting the contoured clinical target volume (CTV) are considered for catheter optimization. Retrospectively generated plans and clinical plans are compared with respect to dosimetric performance and optimization time. All plans were generated with one single run of the optimizer lasting 0.6-97.4 s. Compared to manual optimization, SACO yields a statistically significant (P ≤ 0.05) improved target coverage while at the same time fulfilling all dosimetric constraints for organs at risk (OARs). Comparing inverse planning strategies, dosimetric evaluation for SACO and "hybrid inverse planning and optimization" (HIPO), as gold standard, shows no statistically significant difference (P > 0.05). However, SACO provides the potential to reduce the number of used catheters without compromising plan quality. The proposed heuristic for needle selection provides fast catheter selection with optimization times suited for intraoperative treatment planning. Compared to manual optimization, the

Energy consumption optimization of a continuous ice cream process

International Nuclear Information System (INIS)

González-Ramírez, J.E.; Leducq, D.; Arellano, M.; Alvarez, G.

2013-01-01

Highlights: • This work investigates potential energy savings of an ice cream freezer. • From a full load compressor to a variable speed compressor one in freezer. • 30% less of energy consumption. • It is possible to save between 11 and 14 MWh per year by optimizing freezers. - Abstract: This work investigates potential energy saves in an ice cream freezer by using a variable speed compressor and optimization’s methodology for operating conditions during the process. Two configurations to control the refrigeration capacity were analyzed, the first one, modifies the pressure through the pilot control valve (conventional refrigeration system) and the second one with a variable speed compressor, both with a float expansion valve. Variable speed compressor configuration has showed the highest coefficient of performance and around of 30% less of energy consumption than the conventional one. The optimization of operating conditions in order to minimize the energy consumption is also presented. It was calculated only in France, for all ice cream and sorbet production, it is possible to save energy between 11 and 14 MWh per year by optimizing the operation of the refrigeration system through a variable speed compressor configuration

Neoclassical transport optimization of LHD

Energy Technology Data Exchange (ETDEWEB)

Murakami, S.; Yamada, H.; Watanabe, K.Y. [National Inst. for Fusion Science, Toki, Gifu (Japan); Wakasa, A. [Hokkaido Univ., Graduate School of Engineering, Sapporo, Hokkaido (Japan); Maassberg, H.; Beidler, C.D. [Teilinstitut Greifswald, Max-Planck-Institut fuer Plasmaphysik, Greifswald (Germany)

2002-06-01

Neoclassical transport is studied for LHD configurations in which the magnetic axis has been shifted radially by determining the mono-energetic transport coefficient and the effective helical ripple. With respect to the transport in the long mean free path collisionality region - the so called 1/{nu} transport -, the optimum configuration is found when the magnetic axis has a major radius of 3.53m, which is 0.22m inward shifted from the standard'' configuration of LHD. In the optimized case, the effective helical ripple is very small, remaining below 2% inside 4/5 of the plasma radius. This indicates that a strong inward shift of the magnetic axis in the LHD can diminish the neoclassical transport to a level typical of so-called advanced stellarators''. (author)

Hybrid configurations via percutaneous access for extracorporeal membrane oxygenation: a single-center experience.

Science.gov (United States)

Biscotti, Mauer; Lee, Alison; Basner, Robert C; Agerstrand, Cara; Abrams, Darryl; Brodie, Daniel; Bacchetta, Matthew

2014-01-01

Use of extracorporeal membrane oxygenation (ECMO) in adults has surged in recent years. Typical configurations are venovenous (VV), which provides respiratory support, or venoarterial (VA), which provides both respiratory and circulatory support. In patients supported with VV ECMO who develop hemodynamic compromise, an arterial limb can be added (venovenous-arterial ECMO) to provide additional circulatory support. For patients on VA ECMO who develop concomitant respiratory failure in the setting of some residual cardiac function, an oxygenated reinfusion limb can be added to the internal jugular vein (venoarterial-venous ECMO) to improve oxygen delivery to the cerebral and coronary circulation. Such hybrid configurations can provide differential support for various forms of cardiopulmonary failure. We describe 21 patients who ultimately received a hybrid configuration at our institution between 2012 and 2013. Eight patients (38.1%) died during ECMO support, four patients (19.0%) died after decannulation but before hospital discharge, and nine patients (42.9%) survived to hospital discharge. Our modest survival rate is likely related to the complexity and severity of illness of these patients, and this relative success suggests that hybrid configurations can be effective. It serves patients well to maintain a flexible and adaptable approach to ECMO configurations for their variable cardiopulmonary needs.

Optimization of a phased-array transducer for multiple harmonic imaging in medical applications: frequency and topology.

Science.gov (United States)

Matte, Guillaume M; Van Neer, Paul L M J; Danilouchkine, Mike G; Huijssen, Jacob; Verweij, Martin D; de Jong, Nico

2011-03-01

Second-harmonic imaging is currently one of the standards in commercial echographic systems for diagnosis, because of its high spatial resolution and low sensitivity to clutter and near-field artifacts. The use of nonlinear phenomena mirrors is a great set of solutions to improve echographic image resolution. To further enhance the resolution and image quality, the combination of the 3rd to 5th harmonics--dubbed the superharmonics--could be used. However, this requires a bandwidth exceeding that of conventional transducers. A promising solution features a phased-array design with interleaved low- and high-frequency elements for transmission and reception, respectively. Because the amplitude of the backscattered higher harmonics at the transducer surface is relatively low, it is highly desirable to increase the sensitivity in reception. Therefore, we investigated the optimization of the number of elements in the receiving aperture as well as their arrangement (topology). A variety of configurations was considered, including one transmit element for each receive element (1/2) up to one transmit for 7 receive elements (1/8). The topologies are assessed based on the ratio of the harmonic peak pressures in the main and grating lobes. Further, the higher harmonic level is maximized by optimization of the center frequency of the transmitted pulse. The achievable SNR for a specific application is a compromise between the frequency-dependent attenuation and nonlinearity at a required penetration depth. To calculate the SNR of the complete imaging chain, we use an approach analogous to the sonar equation used in underwater acoustics. The generated harmonic pressure fields caused by nonlinear wave propagation were modeled with the iterative nonlinear contrast source (INCS) method, the KZK, or the Burger's equation. The optimal topology for superharmonic imaging was an interleaved design with 1 transmit element per 6 receive elements. It improves the SNR by ~5 dB compared with

Evaluation and Optimization of Electrode Configuration of Multi-Channel Corona Discharge Plasma for Dye-Containing Wastewater Treatment

International Nuclear Information System (INIS)

Ren Jingyu; Qu Guangzhou; Liang Dongli; Hu Shibin; Wang Tiecheng

2015-01-01

A discharge plasma reactor with a point-to-plane structure was widely studied experimentally in wastewater treatment. In order to improve the utilization efficiency of active species and the energy efficiency of this kind of discharge plasma reactor during wastewater treatment, the electrode configuration of the point-to-plane corona discharge reactor was studied by evaluating the effects of discharge spacing and adjacent point distance on discharge power and discharge energy density, and then dye-containing wastewater decoloration experiments were conducted on the basis of the optimum electrode configuration. The experimental results of the discharge characteristics showed that high discharge power and discharge energy density were achieved when the ratio of discharge spacing to adjacent point distance (d/s) was 0.5. Reactive Brilliant Blue (RBB) wastewater treatment experiments presented that the highest RBB decoloration efficiency was observed at d/s of 0.5, which was consistent with the result obtained in the discharge characteristics experiments. In addition, the biodegradability of RBB wastewater was enhanced greatly after discharge plasma treatment under the optimum electrode configuration. RBB degradation processes were analyzed by GC-MS and IC, and the possible mechanism for RBB decoloration was also discussed. (paper)

Influence of land use configurations on river sediment pollution.

Science.gov (United States)

Liu, An; Duodu, Godfred O; Goonetilleke, Ashantha; Ayoko, Godwin A

2017-10-01

Land use is an influential factor in river sediment pollution. However, land use type alone is found to be inadequate to explain pollutant contributions to the aquatic environment since configurations within the same land use type such as land cover and development layout could also exert an important influence. Consequently, this paper discusses a research study, which consisted of an in-depth investigation into the relationship between land use type and river sediment pollution by introducing robust parameters that represent configurations within the primary land use types. Urban water pollutants, namely, nutrients, total carbon, polycyclic aromatic hydrocarbons and metals were investigated in the study. The outcomes show that higher patch density and more diverse land use development forms contribute relatively greater pollutant loads to receiving waters and consequently leading to higher sediment pollution. The study outcomes are expected to contribute essential knowledge for creating robust management strategies to minimise waterway pollution and thereby protect the health of aquatic ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Local random configuration-tree theory for string repetition and facilitated dynamics of glass

Science.gov (United States)

Lam, Chi-Hang

2018-02-01

We derive a microscopic theory of glassy dynamics based on the transport of voids by micro-string motions, each of which involves particles arranged in a line hopping simultaneously displacing one another. Disorder is modeled by a random energy landscape quenched in the configuration space of distinguishable particles, but transient in the physical space as expected for glassy fluids. We study the evolution of local regions with m coupled voids. At a low temperature, energetically accessible local particle configurations can be organized into a random tree with nodes and edges denoting configurations and micro-string propagations respectively. Such trees defined in the configuration space naturally describe systems defined in two- or three-dimensional physical space. A micro-string propagation initiated by a void can facilitate similar motions by other voids via perturbing the random energy landscape, realizing path interactions between voids or equivalently string interactions. We obtain explicit expressions of the particle diffusion coefficient and a particle return probability. Under our approximation, as temperature decreases, random trees of energetically accessible configurations exhibit a sequence of percolation transitions in the configuration space, with local regions containing fewer coupled voids entering the non-percolating immobile phase first. Dynamics is dominated by coupled voids of an optimal group size, which increases as temperature decreases. Comparison with a distinguishable-particle lattice model (DPLM) of glass shows very good quantitative agreements using only two adjustable parameters related to typical energy fluctuations and the interaction range of the micro-strings.

Application of Configurators in Networks

DEFF Research Database (Denmark)

Malis, Martin; Hvam, Lars

2003-01-01

Shorter lead-time, improved quality of product specifications and better communication with customers and suppliers are benefits derived from the application of configurators. Configurators are knowledge-based IT-systems that can be applied to deal with product knowledge and to support different...... processes in a company. Traditionally, configurators have been used as an internal tool. In this paper focus will be on the application of configurators in a network of companies, and a procedure for developing product configurators in a network of companies will be presented. The aim is to present...... a structured guideline, tools and methods on how to successfully develop configurators in a network perspective. Findings presented in this paper are supported by research in a case company. The results from the empirical work show a huge potential for the application of configurators in networks of companies....

A qualitative examination of wheelchair configuration for optimal mobility performance in wheelchair sports : a pilot study

NARCIS (Netherlands)

Mason, Barry S.; Porcellato, Lorna; van der Woude, Lucas H. V.; Goosey-Tolfrey, Victoria L.

Objective: To examine wheelchair athletes' perceptions of wheelchair configuration in relation to aspects of mobility performance. Methods: Nine elite wheelchair athletes from wheelchair basketball, wheelchair rugby and wheelchair tennis were interviewed using a semi-structured format. Interview

CFD optimization of continuous stirred-tank (CSTR) reactor for biohydrogen production.

Science.gov (United States)

Ding, Jie; Wang, Xu; Zhou, Xue-Fei; Ren, Nan-Qi; Guo, Wan-Qian

2010-09-01

There has been little work on the optimal configuration of biohydrogen production reactors. This paper describes three-dimensional computational fluid dynamics (CFD) simulations of gas-liquid flow in a laboratory-scale continuous stirred-tank reactor used for biohydrogen production. To evaluate the role of hydrodynamics in reactor design and optimize the reactor configuration, an optimized impeller design has been constructed and validated with CFD simulations of the normal and optimized impeller over a range of speeds and the numerical results were also validated by examination of residence time distribution. By integrating the CFD simulation with an ethanol-type fermentation process experiment, it was shown that impellers with different type and speed generated different flow patterns, and hence offered different efficiencies for biohydrogen production. The hydrodynamic behavior of the optimized impeller at speeds between 50 and 70 rev/min is most suited for economical biohydrogen production. Copyright 2010 Elsevier Ltd. All rights reserved.

Optimal control of gun recoil in direct fire using magnetorheological absorbers

International Nuclear Information System (INIS)

Singh, Harinder J; Wereley, Norman M

2014-01-01

Optimal control of a gun recoil absorber is investigated for minimizing recoil loads and maximizing rate of fire. A multi-objective optimization problem was formulated by considering the mechanical model of the recoil absorber employing a spring and a magnetorheological (MR) damper. The damper forces are predicted by evaluating pressure drops using a nonlinear Bingham-plastic model. The optimization methodology provides multiple optimal design configurations with a trade-off between recoil load minimization and increased rate of fire. The configurations with low or high recoil loads imply low or high rate of fire, respectively. The gun recoil absorber performance is also analyzed for perturbations in the firing forces. The adaptive control of the MR damper for varying gun firing forces provides a smooth operation by returning the recoil mass to its battery position (ready to reload and fire) without incurring an end-stop impact. Furthermore, constant load transmissions are observed with respect to the recoil stroke by implementing optimal control during the simulated firing events. (paper)

Optimal control of gun recoil in direct fire using magnetorheological absorbers

Science.gov (United States)

Singh, Harinder J.; Wereley, Norman M.

2014-05-01

Optimal control of a gun recoil absorber is investigated for minimizing recoil loads and maximizing rate of fire. A multi-objective optimization problem was formulated by considering the mechanical model of the recoil absorber employing a spring and a magnetorheological (MR) damper. The damper forces are predicted by evaluating pressure drops using a nonlinear Bingham-plastic model. The optimization methodology provides multiple optimal design configurations with a trade-off between recoil load minimization and increased rate of fire. The configurations with low or high recoil loads imply low or high rate of fire, respectively. The gun recoil absorber performance is also analyzed for perturbations in the firing forces. The adaptive control of the MR damper for varying gun firing forces provides a smooth operation by returning the recoil mass to its battery position (ready to reload and fire) without incurring an end-stop impact. Furthermore, constant load transmissions are observed with respect to the recoil stroke by implementing optimal control during the simulated firing events.

The Design and Analysis of Virtual Network Configuration for a Wireless Mobile ATM Network

Science.gov (United States)

Bush, Stephen F.

1999-05-01

This research concentrates on the design and analysis of an algorithm referred to as Virtual Network Configuration (VNC) which uses predicted future states of a system for faster network configuration and management. VNC is applied to the configuration of a wireless mobile ATM network. VNC is built on techniques from parallel discrete event simulation merged with constraints from real-time systems and applied to mobile ATM configuration and handoff. Configuration in a mobile network is a dynamic and continuous process. Factors such as load, distance, capacity and topology are all constantly changing in a mobile environment. The VNC algorithm anticipates configuration changes and speeds the reconfiguration process by pre-computing and caching results. VNC propagates local prediction results throughout the VNC enhanced system. The Global Positioning System is an enabling technology for the use of VNC in mobile networks because it provides location information and accurate time for each node. This research has resulted in well defined structures for the encapsulation of physical processes within Logical Processes and a generic library for enhancing a system with VNC. Enhancing an existing system with VNC is straight forward assuming the existing physical processes do not have side effects. The benefit of prediction is gained at the cost of additional traffic and processing. This research includes an analysis of VNC and suggestions for optimization of the VNC algorithm and its parameters.

Optimization of doses received by the hospital staff and the members of the family of patients undergoing In - 111 pentetreotide therapy

International Nuclear Information System (INIS)

Kontogeorgakos, D.; Limouris, G.S.; Papanikolos, G.; Vlahos, L.; Carinou, E.; Kamenopoulou, V.; Dimitriou, P.

2005-01-01

Full text: According to the Euratom Directives (96/29, 97/43) the doses received by the workers as well as the family of patients and third persons during medical exposures, obey to the Dose Constraint Levels (DCLs), established by the authorities, in the content of optimization in radiation protection. The aim of this study is to present a radiation protection protocol, concerning the aforementioned group members, for patients undergoing treatment with 111 In pentetreotide, after intra-arterial infusion. The doses to the staff were measured by means of lithium fluoride detectors (TLDs). Two finger, one wrist and one whole body TLD by person were used during the therapy procedure. An electronic personal dosemeter for the monitoring of the dose and the dose rate during the procedure was also provided. The TLDs were calibrated in a SSDL. Measurements were simulated with a Monte Carlo code. The dose rate profile from the syringe in various distances was also simulated in order to estimate doses received by the fingers. The radiopharmaceutical infusion (mean value 5,5GBq/infusion) was performed with a shielded syringe (∼1.7 cm Pb) by the medical doctor standing behind a lead shielding (∼2 cm Pb). The labeling procedure was improved by using 20 ml evacuated vials in order to reduce the injection time of the isotope in the octreotide solution. Before treatment the patient was asked to fill in a questionnaire concerning its life conditions. The time of the release of the patient (48 to 72 hrs following infusion), as well as the content and the duration of the behavior instructions given, were determined by the patient's personal data (i.e. conditions at home and work, use of public transport) and the dose rate values. A direct reading personal dosemeter was used in order to confirm that the dose received by the person accompanying the patient is kept below the DC values. Doses received by the staff during the 111 In therapeutic procedures showed to exceed the

Optimization of levitation and guidance forces in a superconducting Maglev system

Science.gov (United States)

Yildizer, Irfan; Cansiz, Ahmet; Ozturk, Kemal

2016-09-01

Optimization of the levitation for superconducting Maglev systems requires effective use of vertical and guidance forces during the operation. In this respect the levitation and guidance forces in terms of various permanent magnet array configurations are analyzed. The arrangements of permanent magnet arrays interacting with the superconductor are configured for the purpose of increasing the magnetic flux density. According to configurations, modeling the interaction forces between the permanent magnet and the superconductor are established in terms of the frozen image model. The model is complemented with the analytical calculations and provides a reasonable agreement with the experiments. The agreement of the analytical calculation associated with the frozen image model indicates a strong case to establish an optimization, in which provides preliminary analysis before constructing more complex Maglev system.

Optimized Loading for Particle-in-cell Gyrokinetic Simulations

International Nuclear Information System (INIS)

Lewandowski, J.L.V.

2004-01-01

The problem of particle loading in particle-in-cell gyrokinetic simulations is addressed using a quadratic optimization algorithm. Optimized loading in configuration space dramatically reduces the short wavelength modes in the electrostatic potential that are partly responsible for the non-conservation of total energy; further, the long wavelength modes are resolved with good accuracy. As a result, the conservation of energy for the optimized loading is much better that the conservation of energy for the random loading. The method is valid for any geometry and can be coupled to optimization algorithms in velocity space

Compressor airfoil tip clearance optimization system

Science.gov (United States)

Little, David A.; Pu, Zhengxiang

2015-08-18

A compressor airfoil tip clearance optimization system for reducing a gap between a tip of a compressor airfoil and a radially adjacent component of a turbine engine is disclosed. The turbine engine may include ID and OD flowpath boundaries configured to minimize compressor airfoil tip clearances during turbine engine operation in cooperation with one or more clearance reduction systems that are configured to move the rotor assembly axially to reduce tip clearance. The configurations of the ID and OD flowpath boundaries enhance the effectiveness of the axial movement of the rotor assembly, which includes movement of the ID flowpath boundary. During operation of the turbine engine, the rotor assembly may be moved axially to increase the efficiency of the turbine engine.

Optimized molten salt receivers for ultimate trough solar fields

Science.gov (United States)

Riffelmann, Klaus-J.; Richert, Timo; Kuckelkorn, Thomas

2016-05-01

Today parabolic trough collectors are the most successful concentrating solar power (CSP) technology. For the next development step new systems with increased operation temperature and new heat transfer fluids (HTF) are currently developed. Although the first power tower projects have successfully been realized, up to now there is no evidence of an all-dominant economic or technical advantage of power tower or parabolic trough. The development of parabolic trough technology towards higher performance and significant cost reduction have led to significant improvements in competitiveness. The use of molten salt instead of synthetic oil as heat transfer fluid will bring down the levelized costs of electricity (LCOE) even further while providing dispatchable energy with high capacity factors. FLABEG has developed the Ultimate TroughTM (UT) collector, jointly with sbp Sonne GmbH and supported by public funds. Due to its validated high optical accuracy, the collector is very suitable to operate efficiently at elevated temperatures up to 550 °C. SCHOTT will drive the key-innovations by introducing the 4th generation solar receiver that addresses the most significant performance and cost improvement measures. The new receivers have been completely redesigned to provide a product platform that is ready for high temperature operation up to 550 °C. Moreover distinct product features have been introduced to reduce costs and risks in solar field assembly and installation. The increased material and design challenges incurred with the high temperature operation have been reflected in sophisticated qualification and validation procedures.

Project STOP (Spectral Thermal Optimization Program)

Science.gov (United States)

Goldhammer, L. J.; Opjorden, R. W.; Goodelle, G. S.; Powe, J. S.

1977-01-01

The spectral thermal optimization of solar cell configurations for various solar panel applications is considered. The method of optimization depends upon varying the solar cell configuration's optical characteristics to minimize panel temperatures, maximize power output and decrease the power delta from beginning of life to end of life. Four areas of primary investigation are: (1) testing and evaluation of ultraviolet resistant coverslide adhesives, primarily FEP as an adhesive; (2) examination of solar cell absolute spectral response and corresponding cell manufacturing processes that affect it; (3) experimental work with solar cell manufacturing processes that vary cell reflectance (solar absorptance); and (4) experimental and theoretical studies with various coverslide filter designs, mainly a red rejection filter. The Hughes' solar array prediction program has been modified to aid in evaluating the effect of each of the above four areas on the output of a solar panel in orbit.

Simulator configuration maintenance

International Nuclear Information System (INIS)

2006-01-01

Requirements and recommendations of this section defines NPP personnel activity aimed to the provision of the simulator configuration compliance with the current configuration of the power-generating unit-prototype, standard and technical requirements and describe a monitoring procedure for a set of simulator software and hardware, training, organizational and technical documents

A 850 GHz SIS receiver employing silicon micro-machining technology

Science.gov (United States)

Kooi, J. W.; Pety, J.; Schaffer, P. L.; Phillips, T. G.; Bumble, B.; LeDuc, H. G.; Walker, C. K.

1996-01-01

A 850 GHz superconductor-insulator-superconductor (SIS) heterodyne receiver which uses a radiofrequency tuned niobium tunnel junction fabricated on a 1 micron thick silicon nitrate membrane, is reported. From video and heterodyne measurements, it was calculated that the niobium film loss in the radiofrequency matching network is about 6.8 dB at 822 GHz. These results are approximately a factor of two higher than the theoretical loss predicted by the Mattis-Bardeen theory in the extreme anomalous limit. The junction design and the receiver configuration are described, including the mixer block, the membrane construction and the cooled optics. The performance tests using a Fourier transform spectrometer to measure the response of the radiofrequency matching network, and the SIS simulations of the receiver response to cold and hot loads, the infrared noise contribution and the overall mixer conversion efficiency, are reported. It is concluded that the receiver response is limited by the absorption loss in the radiofrequency matching network.

Phase calibration approaches for radar interferometry and imaging configurations: equatorial spread F results

Directory of Open Access Journals (Sweden)

J. L. Chau

2008-08-01

Full Text Available In recent years, more and more radar systems with multiple-receiver antennas are being used to study the atmospheric and ionospheric irregularities with either interferometric and/or imaging configurations. In such systems, one of the major challenges is to know the phase offsets between the different receiver channels. Such phases are intrinsic to the system and are due to different cable lengths, filters, attenuators, amplifiers, antenna impedance, etc. Moreover, such phases change as function of time, on different time scales, depending on the specific installation. In this work, we present three approaches using natural targets (radio stars, meteor-head and meteor trail echoes that allow either an absolute or relative phase calibration. In addition, we present the results of using an artificial source (radio beacon for a continuous calibration that complements the previous approaches. These approaches are robust and good alternatives to other approaches, e.g. self-calibration techniques using known data features, or for multiple-receiver configurations constantly changing their receiving elements. In order to show the good performance of the proposed phase calibration techniques, we present new radar imaging results of equatorial spread F (ESF irregularities. Finally we introduce a new way to represent range-time intensity (RTI maps color coded with the Doppler information. Such modified map allows the identification and interpretation of geophysical phenomena, previously hidden in conventional RTI maps, e.g. the time and altitude of occurrence of ESF irregularities pinching off from the bottomside and their respective Doppler velocity.

Application of a heuristic search method for generation of fuel reload configurations

International Nuclear Information System (INIS)

Galperin, A.; Nissan, E.

1988-01-01

A computerized heuristic search method for the generation and optimization of fuel reload configurations is proposed and investigated. The heuristic knowledge is expressed modularly in the form of ''IF-THEN'' production rules. The method was implemented in a program coded in the Franz LISP programming language and executed under the UNIX operating system. A test problem was formulated, based on a typical light water reactor reload problem with a few simplifications assumed, in order to allow formulation of the reload strategy into a relatively small number of rules. A computer run of the problem was performed with a VAX-780 machine. A set of 312 solutions was generated in -- 20 min of execution time. Testing of a few arbitrarily chosen configurations demonstrated reasonably good performance for the computer-generated solutions. A computerized generator of reload configurations may be used for the fast generation or modification of reload patterns and as a tool for the formulation, tuning, and testing of the heuristic knowledge rules used by an ''expert'' fuel manager

Dynamic airspace configuration method based on a weighted graph model

Directory of Open Access Journals (Sweden)

Chen Yangzhou

2014-08-01

Full Text Available This paper proposes a new method for dynamic airspace configuration based on a weighted graph model. The method begins with the construction of an undirected graph for the given airspace, where the vertices represent those key points such as airports, waypoints, and the edges represent those air routes. Those vertices are used as the sites of Voronoi diagram, which divides the airspace into units called as cells. Then, aircraft counts of both each cell and of each air-route are computed. Thus, by assigning both the vertices and the edges with those aircraft counts, a weighted graph model comes into being. Accordingly the airspace configuration problem is described as a weighted graph partitioning problem. Then, the problem is solved by a graph partitioning algorithm, which is a mixture of general weighted graph cuts algorithm, an optimal dynamic load balancing algorithm and a heuristic algorithm. After the cuts algorithm partitions the model into sub-graphs, the load balancing algorithm together with the heuristic algorithm transfers aircraft counts to balance workload among sub-graphs. Lastly, airspace configuration is completed by determining the sector boundaries. The simulation result shows that the designed sectors satisfy not only workload balancing condition, but also the constraints such as convexity, connectivity, as well as minimum distance constraint.

A Scalable and Highly Configurable Cache-Aware Hybrid Flash Translation Layer

Directory of Open Access Journals (Sweden)

Jalil Boukhobza

2014-03-01

Full Text Available This paper presents a cache-aware configurable hybrid flash translation layer (FTL, named CACH-FTL. It was designed based on the observation that most state-of­­-the-art flash-specific cache systems above FTLs flush groups of pages belonging to the same data block. CACH-FTL relies on this characteristic to optimize flash write operations placement, as large groups of pages are flushed to a block-mapped region, named BMR, whereas small groups are buffered into a page-mapped region, named PMR. Page group placement is based on a configurable threshold defining the limit under which it is more cost-effective to use page mapping (PMR and wait for grouping more pages before flushing to the BMR. CACH-FTL is scalable in terms of mapping table size and flexible in terms of Input/Output (I/O workload support. CACH-FTL performs very well, as the performance difference with the ideal page-mapped FTL is less than 15% in most cases and has a mean of 4% for the best CACH-FTL configurations, while using at least 78% less memory for table mapping storage on RAM.

Optimization of insulation of a linear Fresnel collector

Science.gov (United States)

Ardekani, Mohammad Moghimi; Craig, Ken J.; Meyer, Josua P.

2017-06-01

This study presents a simulation based optimization study of insulation around the cavity receiver of a Linear Fresnel Collector. This optimization study focuses on minimizing heat losses from a cavity receiver (maximizing plant thermal efficiency), while minimizing insulation cross-sectional area (minimizing material cost and cavity dead load), which leads to a cheaper and thermally more efficient LFC cavity receiver.

Low Complexity Receiver Design for MIMO-Radar

KAUST Repository

Ahmed, Sajid

2012-09-08

In this work, an algorithm for the multiple-input multiple-output (MIMO) radar is proposed. It has low computational complexity compared to the available schemes, and relatively low side-lobe-levels in the receive beampattern compared to the phased-array and MIMO-radar. In the proposed algorithm, the received signal vector of MIMO-radar is divided into sub-vectors, and each sub-vector is multiplied with the corresponding weight vector. The number of sub-vectors and weight vectors are optimally found to maximise the received signal power from the target of interest direction. The proposed scheme can be effectively applied in passive radars to minimise the side-lobe levels and place deep nulls for interferers in the receive beampattern. Simulation results show that the proposed scheme has relatively lower side lobe levels and better detection capabilities compared to MIMO-radar and phased-array.

Low Complexity Receiver Design for MIMO-Radar

KAUST Repository

Ahmed, Sajid; Alouini, Mohamed-Slim

2012-01-01

In this work, an algorithm for the multiple-input multiple-output (MIMO) radar is proposed. It has low computational complexity compared to the available schemes, and relatively low side-lobe-levels in the receive beampattern compared to the phased-array and MIMO-radar. In the proposed algorithm, the received signal vector of MIMO-radar is divided into sub-vectors, and each sub-vector is multiplied with the corresponding weight vector. The number of sub-vectors and weight vectors are optimally found to maximise the received signal power from the target of interest direction. The proposed scheme can be effectively applied in passive radars to minimise the side-lobe levels and place deep nulls for interferers in the receive beampattern. Simulation results show that the proposed scheme has relatively lower side lobe levels and better detection capabilities compared to MIMO-radar and phased-array.

Optimization of typical diffuse herbicide pollution control by soil amendment configurations under four levels of rainfall intensities.

Science.gov (United States)

Ouyang, Wei; Huang, Weijia; Wei, Peng; Hao, Fanghua; Yu, Yongyong

2016-06-15

Herbicides are a main source of agricultural diffuse pollution due to their wide application in tillage practices. The aim of this study is to optimize the control efficiency of the herbicide atrazine with the aid of modified soil amendments. The soil amendments were composed of a combination of biochar and gravel. The biochar was created from corn straw with a catalytic pyrolysis of ammonium dihydrogen phosphate. The leaching experiments under four rainfall conditions were measured for the following designs: raw soil, soil amended with gravel, biochar individually and together with gravel. The control efficiency of each design was also identified. With the designed equipment, the atrazine content in the contaminant load layer, gravel substrate layer, biochar amendment layer and soil layer was measured under four types of rainfall intensities (1.25 mm/h, 2.50 mm/h, 5.00 mm/h and 10.00 mm/h). Furthermore, the vertical distribution of atrazine in the soil sections was also monitored. The results showed that the herbicide leaching load increased under the highest rainfall intensity in all designs. The soil with the combination of gravel and biochar provided the highest control efficiency of 87.85% on atrazine when the additional proportion of biochar was 3.0%. The performance assessment under the four kinds of rainfall intensity conditions provided the guideline for the soil amendment configuration. The combination of gravel and biochar is recommended as an efficient method for controlling diffuse herbicide pollution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Post Pareto optimization-A case

Science.gov (United States)

Popov, Stoyan; Baeva, Silvia; Marinova, Daniela

2017-12-01

Simulation performance may be evaluated according to multiple quality measures that are in competition and their simultaneous consideration poses a conflict. In the current study we propose a practical framework for investigating such simulation performance criteria, exploring the inherent conflicts amongst them and identifying the best available tradeoffs, based upon multi-objective Pareto optimization. This approach necessitates the rigorous derivation of performance criteria to serve as objective functions and undergo vector optimization. We demonstrate the effectiveness of our proposed approach by applying it with multiple stochastic quality measures. We formulate performance criteria of this use-case, pose an optimization problem, and solve it by means of a simulation-based Pareto approach. Upon attainment of the underlying Pareto Frontier, we analyze it and prescribe preference-dependent configurations for the optimal simulation training.

Multi-objective optimization under uncertainty for sheet metal forming

Directory of Open Access Journals (Sweden)

Lafon Pascal

2016-01-01

Full Text Available Aleatory uncertainties in material properties, blank thickness and friction condition are inherent and irreducible variabilities in sheet metal forming. Optimal design configurations, which are obtained by conventional design optimization methods, are not always able to meet the desired targets due to the effect of uncertainties. This paper proposes a multi-objective robust design optimization that aims to tackle this problem. Results obtained on a U shape draw bending benchmark show that spring-back effect can be controlled by optimizing process parameters.

Shape and topology optimization of enzymatic microreactors

DEFF Research Database (Denmark)

Pereira Rosinha, Ines

for effective and cost efficient reactors for pharmaceutical processes forces the industry to search for better technologies. In biochemical engineering, the used reactor design in a given process is usually limited to a range of well-established configurations and layouts. Usually the implemented reactors...... in a chemical process do not always yield in the best reaction conditions.This thesis develops an innovative application of topology and shape optimization methods to achemical engineering problem. The main goal is to design a reactor according to the limitations of the reaction system by modifying the reactor...... configuration. In this thesis structural optimization methods were exclusively applied to enzymatic microreactors. The case studies were chosen such that they can be experimentally tested afterwards. In this way, the design of the reactor is customized to the reaction system and itcontributes to the reduction...

Parsing the Dictionary of Modern Literary Russian Language with the Method of SCD Configurations. The Lexicographic Modeling

Directory of Open Access Journals (Sweden)

Neculai Curteanu

2012-05-01

Full Text Available This paper extends the experience of parsing other five, sensibly different, Romanian, French, and German largest dictionaries, to \\textbf{\\textit{DMLRL}} (Dictionary of Modern Literary Russian Language [18], using the optimal and portable parsing method of SCD (Segmentation-Cohesion-Dependency configurations [7], [11], [15]. The purpose of the present paper is to elaborate the lexicographic modeling of \\textbf{\\textit{DMLRL}}, which necessarily precedes the sense tree parsing dictionary entries. The following \\textbf{\\textit{three}} SCD configurations are described: the \\textbf{\\textit{first one}} has to separate the lexicographic segments in a \\textbf{\\textit{DMLRL}} entry, the \\textbf{\\textit{second}} SCD-configuration concentrates on the SCD marker classes and their hypergraph hierarchy for \\textbf{\\textit{DMLRL}} primary and secondary senses, while the \\textbf{\\textit{third}} SCD configuration hands down the same modeling process to the atomic sense definitions and their examples-to-definitions. The dependency hypergraph of the third SCD configuration, interconnected to the one of the second SCD configuration, is specified completely at the atomic sense level for the first time, exceeding the SCD configuration modeling for other five dictionaries [15], [14]. Numerous examples from \\textbf{\\textit{DMLRL}} and comparison to \\textbf{\\textit{DLR-DAR}} Romanian thesaurus-dictionary support the proposed \\textbf{\\textit{DMLRL}} lexicographic modeling.

Thermo-economic optimization of heat recovery steam generator for a range of gas turbine exhaust temperatures

International Nuclear Information System (INIS)

Nadir, Mahmoud; Ghenaiet, Adel; Carcasci, Carlo

2016-01-01

Highlights: • Thermo-economic optimization of HRSG configurations. • The maximum value of the net present value was targeted for the economic optimization. • Three level HRSG is the best option in respect of power output and high priced medium. • Two level HRSG is the best for net benefit in low and intermediate priced mediums. - Abstract: This paper illustrates the effect of selling price on the optimum design parameters of a heat recovery steam generator (HRSG) and the selection of its ideal configuration for an outlet temperature range of 350–650 °C. The Particle Swarm Optimization (PSO) method was used, considering the steam cycle specific work as an objective to be maximized, the net present value as another objective to be maximized for the economic optimization and a combination of both. Three configurations of heat recovery steam generators are considered with one, two and three pressure levels and a reheat. The results show that, the three pressure level system is the best configuration from a thermodynamic point of view, but with respect to the economical aspect the two pressure levels is the best configuration for the low and medium selling prices (0.04 $/kW h, 0.08 $/kW h and 0.2 $/kW h), whereas the three pressure level configuration would only be interesting for a high selling price of 0.3 $/kW h and a temperature range 450–600 °C. For a temperature of 650 °C, the high cost of the three level system leads to a decrease in the net present value. As the selling price increases the optimized design parameters of the three pressure level HRSG based on economic or thermodynamic optimization are similar. The obtained results are used to elaborate a new correlation relating the net present value with the gas turbine outlet temperature, gas mass flow rate, number of levels of HRSG and selling price.

Optimizing Stellarators for Turbulent Transport

International Nuclear Information System (INIS)

Mynick, H.E.; Pomphrey, N.; Xanthopoulos, P.

2010-01-01

Up to now, the term 'transport-optimized' stellarators has meant optimized to minimize neoclassical transport, while the task of also mitigating turbulent transport, usually the dominant transport channel in such designs, has not been addressed, due to the complexity of plasma turbulence in stellarators. Here, we demonstrate that stellarators can also be designed to mitigate their turbulent transport, by making use of two powerful numerical tools not available until recently, namely gyrokinetic codes valid for 3D nonlinear simulations, and stellarator optimization codes. A first proof-of-principle configuration is obtained, reducing the level of ion temperature gradient turbulent transport from the NCSX baseline design by a factor of about 2.5.

Spatial Rack Drives Pitch Configurations: Essence and Content

Science.gov (United States)

Abadjieva, Emilia; Abadjiev, Valentin; Naganawa, Akihiro

2018-03-01

The practical realization of all types of mechanical motions converters is preceded by solving the task of their kinematic synthesis. In this way, the determination of the optimal values of the constant geometrical parameters of the chosen structure of the created mechanical system is achieved. The searched result is a guarantee of the preliminary defined kinematic characteristics of the synthesized transmission and in the first place, to guarantee the law of motions transformation. The kinematic synthesis of mechanical transmissions is based on adequate mathematical modelling of the process of motions transformation and on the object, realizing this transformation. Basic primitives of the mathematical models for synthesis upon a pitch contact point are geometric and kinematic pitch configurations. Their dimensions and mutual position in space are the input parameters for the processes of design and elaboration of the synthesized mechanical device. The study presented here is a brief review of the theory of pitch configurations. It is an independent scientific branch of the spatial gearing theory (theory of hyperboloid gears). On this basis, the essence and content of the corresponding primitives, applicable to the synthesis of spatial rack drives, are defined.

Optimized biological nitrogen removal of high-strength ammonium wastewater by activated sludge modeling

Directory of Open Access Journals (Sweden)

Abdelsalam Elawwad

2018-09-01

Full Text Available Wastewater containing high ammonium concentrations is produced from various industrial activities. In this study, the author used a complex activated sludge model, improved by utilizing BioWin© (EnviroSim, Hamilton, Canada simulation software, to gain understanding of the problem of instability in biological nitrogen removal (BNR. Specifically, the study focused on BNR in an industrial wastewater treatment plant that receives high-strength ammonium wastewater. Using the data obtained from a nine-day sampling campaign and routinely measured data, the model was successfully calibrated and validated, with modifications to the sensitive stoichiometric and kinetic parameters. Subsequently, the calibrated model was employed to study various operating conditions in order to optimize the BNR. These operating conditions include alkalinity addition, sludge retention time, and the COD/N ratio. The addition of a stripping step and modifications to the configuration of the aerators are suggested by the author to increase the COD/N ratio and therefore enhance denitrification. It was found that the calibrated model could successfully represent and optimize the treatment of the high-strength ammonium wastewater.

Remembering facial configurations.

Science.gov (United States)

Bruce, V; Doyle, T; Dench, N; Burton, M

1991-02-01

Eight experiments are reported showing that subjects can remember rather subtle aspects of the configuration of facial features to which they have earlier been exposed. Subjects saw several slightly different configurations (formed by altering the relative placement of internal features of the face) of each of ten different faces, and they were asked to rate the apparent age and masculinity-femininity of each. Afterwards, subjects were asked to select from pairs of faces the configuration which was identical to one previously rated. Subjects responded strongly to the central or "prototypical" configuration of each studied face where this was included as one member of each test pair, whether or not it had been studied (Experiments 1, 2 and 4). Subjects were also quite accurate at recognizing one of the previously encountered extremes of the series of configurations that had been rated (Experiment 3), but when unseen prototypes were paired with seen exemplars subjects' performance was at chance (Experiment 5). Prototype learning of face patterns was shown to be stronger than that for house patterns, though both classes of patterns were affected equally by inversion (Experiment 6). The final two experiments demonstrated that preferences for the prototype could be affected by instructions at study and by whether different exemplars of the same face were shown consecutively or distributed through the study series. The discussion examines the implications of these results for theories of the representation of faces and for instance-based models of memory.

Incorporating prior knowledge into beam orientation optimization in IMRT

International Nuclear Information System (INIS)

Pugachev, Andrei M.S.; Lei Xing

2002-01-01

Purpose: Selection of beam configuration in currently available intensity-modulated radiotherapy (IMRT) treatment planning systems is still based on trial-and-error search. Computer beam orientation optimization has the potential to improve the situation, but its practical implementation is hindered by the excessive computing time associated with the calculation. The purpose of this work is to provide an effective means to speed up the beam orientation optimization by incorporating a priori geometric and dosimetric knowledge of the system and to demonstrate the utility of the new algorithm for beam placement in IMRT. Methods and Materials: Beam orientation optimization was performed in two steps. First, the quality of each possible beam orientation was evaluated using beam's-eye-view dosimetrics (BEVD) developed in our previous study. A simulated annealing algorithm was then employed to search for the optimal set of beam orientations, taking into account the BEVD scores of different incident beam directions. During the calculation, sampling of gantry angles was weighted according to the BEVD score computed before the optimization. A beam direction with a higher BEVD score had a higher probability of being included in the trial configuration, and vice versa. The inclusion of the BEVD weighting in the stochastic beam angle sampling process made it possible to avoid spending valuable computing time unnecessarily at 'bad' beam angles. An iterative inverse treatment planning algorithm was used for beam intensity profile optimization during the optimization process. The BEVD-guided beam orientation optimization was applied to an IMRT treatment of paraspinal tumor. The advantage of the new optimization algorithm was demonstrated by comparing the calculation with the conventional scheme without the BEVD weighting in the beam sampling. Results: The BEVD tool provided useful guidance for the selection of the potentially good directions for the beams to incident and was used

A unix configuration engine

International Nuclear Information System (INIS)

Burgess, M.

1994-06-01

A high level description language is presented for the purpose of automatically configuring large heterogeneous networked unix environments, based on class-oriented abstractions. The configuration engine is portable and easily extensible

Weight optimization of an aerobrake structural concept for a lunar transfer vehicle

Science.gov (United States)

Bush, Lance B.; Unal, Resit; Rowell, Lawrence F.; Rehder, John J.

1992-01-01

An aerobrake structural concept for a lunar transfer vehicle was weight optimized through the use of the Taguchi design method, finite element analyses, and element sizing routines. Six design parameters were chosen to represent the aerobrake structural configuration. The design parameters included honeycomb core thickness, diameter-depth ratio, shape, material, number of concentric ring frames, and number of radial frames. Each parameter was assigned three levels. The aerobrake structural configuration with the minimum weight was 44 percent less than the average weight of all the remaining satisfactory experimental configurations. In addition, the results of this study have served to bolster the advocacy of the Taguchi method for aerospace vehicle design. Both reduced analysis time and an optimized design demonstrated the applicability of the Taguchi method to aerospace vehicle design.

Optimal oxygen feeding policy to maximize the production of Maleic anhydride in unsteady state fixed bed catalytic reactors

Directory of Open Access Journals (Sweden)

E. Ali

2017-07-01

Full Text Available The effect of different oxygen feeding scenarios in a fixed bed reactor for the production of Maleic anhydride (MA is studied. Two reactor configurations were examined. In the first configuration, a cross flow reactor (CFR with 4 discrete feeding points is considered. Another configuration is the conventional packed-bed reactor (PBR with a single feed. Nonlinear Model Predictive Controller (NLMPC was used as optimal controller to operate the CFR in dynamic mode and to optimize the multiple feed dosages in order to enhance the MA yield. The simulation results indicated that different combinations of the four feed ratios can operate the reactor at the best value for the yield provided the first feeding point is kept as low as possible. For the packed bed reactor configuration, a single oxygen feed is considered and is optimized transiently by NLMPC. The simulation outcomes showed that the reactor performance in terms of the produced MA mole fraction can also be enhanced to the same magnitude obtained by CFR configuration. This improvement requires decreasing the oxygen ratio in the reactor single feed by 70%.

Modeling and characterization of electret based vibration energy harvesters in slot-effect configuration

International Nuclear Information System (INIS)

Renaud, M; Altena, G; Elfrink, R; Goedbloed, M; De Nooijer, C; Van Schaijk, R

2015-01-01

The purpose of this article is to elaborate a model and the optimization guidelines for electret based harvesters with a specific electret/electrodes configuration, namely the slot-effect configuration. Slot-effect configured harvesters have been investigated experimentally by several research groups. A model describing their dynamic behavior has also been recently proposed in the literature. However, the simplifications used in the existing model can lead to inaccuracies and a refined analysis is elaborated in the present article. The model is compared with experimental measurements on MEMS fabricated devices with a corrugated electret. The electrodes dimensioning in the MEMS device are chosen so that the harvester behaves in a quasi-linear manner over its full range of displacement. This quasi-linearity simplifies greatly the device optimization. Indeed, the behavior of the developed electrostatic harvester is shown to be very comparable to that of piezoelectric harvesters, which are very well understood and documented. The influence of several design parameters on output power performance is investigated. As long as pull-in and breakdown voltage effects can be avoided, the electret surface potential should be maximized and the air gap minimized. We also investigate theoretically the influence of three types of electret on the generated power: planar, corrugated with partial charge coverage, and corrugated with full charge coverage. With the dimensions corresponding to our MEMS devices, the output power characteristics for the three types of electret are similar. However, it is shown that this is not always true. In some conditions, corrugated electrets with full charge coverage are detrimental for the generated power. (paper)

Parametric studies of target/moderator configurations for the Weapons Neutron Research (WNR) facility

International Nuclear Information System (INIS)

Russell, G.J.; Seeger, P.A.; Fluharty, R.G.

1977-03-01

Parametric studies, using continuous-energy Monte Carlo codes, were done to optimize the neutronics of the Weapons Neutron Research (WNR) target and three possible target/moderator configurations: slab target/slab moderators, cylindrical target/cylindrical moderator, and cylindrical target/double-wing moderators. The energy range was 0.5 eV to 800 MeV. A general figure-of-merit (FOM) approach was used. The WNR facility performance can be doubled or tripled by optimizing the target and target/moderator configurations; this approach is more efficient than increasing the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator power by an equivalent factor. A bare target should be used for neutron energies above approximately 100 keV. The FOM for the slab target/slab moderator configuration is the best by a factor of at least 2 to 3 below approximately 1 keV. The total neutron leakage from 0.5 eV to 100 keV through a 100- by 100-mm area centered at the peak leakage is largest for the slab moderator, exceeding that of the cylindrical moderator and double-wing moderator by factors of 1.7 and 3.4, respectively. The neutron leakage at 1 eV from one 300- by 150-mm surface of a slab moderator is 1.5 times larger than that from one 155- by 150-mm surface of a cylindrical moderator. When compared with the 1-eV leakage from two 100- by 150-mm surfaces of a double-wing moderator, that from the slab moderator is 3.4 times larger. 107 figures, 13 tables

Configuration management theory, practice, and application

CERN Document Server

Quigley, Jon M

2015-01-01

Configuration Management: Theory, Practice, and Application details a comprehensive approach to configuration management from a variety of product development perspectives, including embedded and IT. It provides authoritative advice on how to extend products for a variety of markets due to configuration options. The book also describes the importance of configuration management to other parts of the organization. It supplies an overview of configuration management and its process elements to provide readers with a contextual understanding of the theory, practice, and application of CM. Explaining what a configuration item is and what it implies, the book illustrates the interplay of configuration and data management with all enterprise resources during each phase of a product lifecycle. It also demonstrates the interrelationship of CM to functional resources. Shedding light on current practice, the book describes CM baselines, configuration identification, management baseline changes, and acceptance criteria ...

Optimal planning of gas turbine cogeneration system based on linear programming. Paper no. IGEC-1-ID09

International Nuclear Information System (INIS)

Oh, S.-D.; Kwak, H.-Y.

2005-01-01

An optimal planning for gas turbine cogeneration system has been studied. The planning problem considered in this study is to determine the optimal configuration of the system equipments and optimal operational policy of the system when the annual energy demands of electric power, heat and cooling are given a priori. The main benefit of the optimal planning is to minimize operational costs and to save energy by efficient energy utilization. A mixed-integer linear programming and the branch and bound algorithm have been adopted to obtain the optimal solution. Both the optimal configuration of the system equipments and the optimal operation policy has been obtained based on annual cost method. The planning method employed here may be applied to the planning problem of the cogeneration plant to any specific building or hotel. (author)

Wake-up receiver based ultra-low-power WBAN

CERN Document Server

Lont, Maarten; Roermund, Arthur van

2014-01-01

This book presents the cross-layer design and optimization of wake-up receivers for wireless body area networks (WBAN), with an emphasis on low-power circuit design. This includes the analysis of medium access control (MAC) protocols, mixer-first receiver design, and implications of receiver impairments on wideband frequency-shift-keying (FSK) receivers. Readers will learn how the overall power consumption is reduced by exploiting the characteristics of body area networks. Theoretical models presented are validated with two different receiver implementations, in 90nm and 40nm CMOS technology.   • Provides an overview of wireless body area network design from the network layer to the circuit implementation, and an overview of the cross-layer design trade-offs; • Discusses design at both the network or MAC-layer and circuit-level, with an emphasis on circuit design; • Covers the design of low-power frequency shift keying (FSK) wake-up-receivers; • Validates theory presented with two different recei...