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Sample records for loading pattern optimisation

  1. Optimisation of load control

    Energy Technology Data Exchange (ETDEWEB)

    Koponen, P. [VTT Energy, Espoo (Finland)

    1998-08-01

    Electricity cannot be stored in large quantities. That is why the electricity supply and consumption are always almost equal in large power supply systems. If this balance were disturbed beyond stability, the system or a part of it would collapse until a new stable equilibrium is reached. The balance between supply and consumption is mainly maintained by controlling the power production, but also the electricity consumption or, in other words, the load is controlled. Controlling the load of the power supply system is important, if easily controllable power production capacity is limited. Temporary shortage of capacity causes high peaks in the energy price in the electricity market. Load control either reduces the electricity consumption during peak consumption and peak price or moves electricity consumption to some other time. The project Optimisation of Load Control is a part of the EDISON research program for distribution automation. The following areas were studied: Optimization of space heating and ventilation, when electricity price is time variable, load control model in power purchase optimization, optimization of direct load control sequences, interaction between load control optimization and power purchase optimization, literature on load control, optimization methods and field tests and response models of direct load control and the effects of the electricity market deregulation on load control. An overview of the main results is given in this chapter

  2. Reflector modelization in neutronic and optimization methods applied to fuel loading pattern; Modelisation du reflecteur en neutronique et methodes d`optimisation appliquees aux plans de rechargement

    Energy Technology Data Exchange (ETDEWEB)

    Argaud, J.P.

    1995-12-01

    I Physical description of P.W.R nuclear core can be handled by multigroup neutronic diffusion model. We are interested in two problems, using the same approach for the optimization aspect. To deal with some differences between calculations and measurements, the question of their reduction is then introduced. A reflector parameters identification from core measurements is then purposed, the reflector being at the present time the less known part of core diffusion model. This approach conducts to study the reflector model, in particular by an analysis of its transport origin. It leads finally to a new model of reflector described by boundary operators using an integral formulation on the core/reflector interface. That is on this new model that a parameter identification formulation of calculations-measurements differences reduction is given, using an adjoint state formulation to minimize errors by a gradient method. Furthermore, nuclear fuel reload of P.W.R core needs an optimal distribution of fuel assemblies, namely a loading pattern. This combinatorial optimization problem is then expressed as a cost function minimization, the cost function describing the power spatial distribution. Various methods (linear programming, simulated annealing,...), used to solve this problem, are detailed, given in particular a practical search example. A new approach is then proposed, using the gradient of the cost function to direct the search in the patterns discrete space. Final results of complete patterns search trials are presented, and compared to those obtained by other methods. In particular the results are obtained very quickly. (author). 81 refs., 55 figs., 5 appends.

  3. Stacking sequence optimisation of composite panels subjected to slamming impact loads using a genetic algorithm

    OpenAIRE

    Khedmati,Mohammad Reza; Sangtabi,Mohammad Rezai; Fakoori,Mehdi

    2013-01-01

    Optimisation of stacking sequence for composite panels under slamming impact loads using a genetic algorithm method is studied in this paper. For this purpose, slamming load is assumed to have a uniform distribution with a triangular-pulse type of intensity function. In order to perform optimisation based on a genetic algorithm, a special code is written in MATLAB software environment. The optimiser is coupled with the commercial software ANSYS in order to analyse the composite panel under st...

  4. Load optimised piezoelectric generator for powering battery-less TPMS

    Science.gov (United States)

    Blažević, D.; Kamenar, E.; Zelenika, S.

    2013-05-01

    The design of a piezoelectric device aimed at harvesting the kinetic energy of random vibrations on a vehicle's wheel is presented. The harvester is optimised for powering a Tire Pressure Monitoring System (TPMS). On-road experiments are performed in order to measure the frequencies and amplitudes of wheels' vibrations. It is hence determined that the highest amplitudes occur in an unperiodic manner. Initial tests of the battery-less TPMS are performed in laboratory conditions where tuning and system set-up optimization is achieved. The energy obtained from the piezoelectric bimorph is managed by employing the control electronics which converts AC voltage to DC and conditions the output voltage to make it compatible with the load (i.e. sensor electronics and transmitter). The control electronics also manages the sleep/measure/transmit cycles so that the harvested energy is efficiently used. The system is finally tested in real on-road conditions successfully powering the pressure sensor and transmitting the data to a receiver in the car cockpit.

  5. Smart meter deployment optimisation and its analysis for appliance load monitoring

    Directory of Open Access Journals (Sweden)

    Ahmed Shaharyar Khwaja

    2015-04-01

    Full Text Available In this study, the authors study the problem of smart meter deployment optimisation for appliance load monitoring, that is, to monitor a number of devices without any ambiguity using the minimum number of low-cost smart meters. The importance of this problem is due to the fact that the number of meters should be reduced to decrease the deployment cost, improve reliability and decrease congestion. In this way, in future, smart meters can provide additional information about the type and number of distinct devices connected, besides their normal functionalities concerned with providing overall energy measurements and their communication. The authors present two exact smart meter deployment optimisation algorithms, one based on exhaustive search and the other based on efficient implementation of the exhaustive search. They formulate the problem mathematically and present computational complexity analysis of their algorithms. Simulation scenarios show that for a typical number of home appliances, the efficient search method is significantly faster compared to the exhaustive search and can provide the same optimal solution. The authors also show the dependency of their method on the distribution of the load pattern that can potentially be in a typical household.

  6. Review: Optimising cognitive load and usability to improve the ...

    African Journals Online (AJOL)

    This is seldom the case when e-learning resources are developed, especially in ... resources, as learners experience difficulties with the technology interface while ... The fields of cognitive load theory and human-computer interaction share a ...

  7. Optimisation models and solution methods for load management

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Stig-Inge [Linkoeping Univ. (Sweden). Div. of Wood Science and Technology; Roennqvist, Mikael; Claesson, Marcus [Linkoeping Univ. (Sweden). Div. of Optimisation

    2001-02-01

    The electricity market in Sweden has changed during recent years. Electricity for industrial use can nowadays be purchased from a number of competing electricity suppliers. Hence, the price for each kilowatt-hour is significantly lower than just two years ago and the interest for electricity conservation measures has declined. Part of the electricity tariff is, however, almost the same as before, i.e. the demand cost expressed in Swedish Kronor, SEK, for each kilowatt. This has put focus on load management measures in order to decrease this specific cost. Saving one kWh might lead to monetary savings between 0.22 to 914 SEK and this paper shows how to save only those kWh which really save money. A load management system has been installed in a small carpentry factory and the device can turn off equipment due to a certain priority and for a number of minutes each hour. The question is now, what level on the electricity load is optimal in a strict mathematical sense, i.e. how many kW should be set in the load management computer in order to get the best profitability? In this paper we develop a mathematical model which can be used both as a tool to find a best profitable subscription level and as a tool to control the turn of choices. Numerical results from a case study are presented.

  8. Optimisation of the Crack Pattern in Continuously Reinforced Concrete Pavements

    NARCIS (Netherlands)

    Ren, D.

    2015-01-01

    Recent field investigations on several new Continuously Reinforced Concrete Pavements (CRCP) in Belgium indicate that its crack pattern is characterized by low mean crack spacing along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to si

  9. Optimisation of the Crack Pattern in Continuously Reinforced Concrete Pavements

    NARCIS (Netherlands)

    Ren, D.

    2015-01-01

    Recent field investigations on several new Continuously Reinforced Concrete Pavements (CRCP) in Belgium indicate that its crack pattern is characterized by low mean crack spacing along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to si

  10. Optimisation of the Crack Pattern in Continuously Reinforced Concrete Pavements

    NARCIS (Netherlands)

    Ren, D.

    2015-01-01

    Recent field investigations on several new Continuously Reinforced Concrete Pavements (CRCP) in Belgium indicate that its crack pattern is characterized by low mean crack spacing along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to

  11. Lateral load pattern in pushover analysis

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The seismic capacity curves of three types of buildings including frame, frame-shear wall and shear wall obtained by pushover analysis under different lateral load patterns are compared with those from nonlinear time history analysis. Based on the numerical results obtained a two-phase load pattern: an inverted triangle(first mode)load pattern until the base shear force reaches β times its maximum value,Vmax, followed by a(x/H)α form, here β and α being some coefficients depending on the type of the structures considered, is proposed in the paper, which can provide excellent approximation of the seismic capacity curve for low-to-mid-rise shear type buildings. Furthermore, it is shown both the two-phase load pattern proposed and the invariant uniform pattern can be used for low-to-mid-rise shear-bending type and low-rise bending type of buildings. No suitable load patterns have been found for high-rise buildings.

  12. Constrained optimisation in granular network flows: Games with a loaded dice

    Science.gov (United States)

    Lin, Qun; Tordesillas, Antoinette

    2013-06-01

    Flows in real world networks are rarely the outcome of unconditional random allocations as, say, the roll of a dice. Think, for example, of force transmission through a contact network in a quasistatically deforming granular material. Forces `flow' through this network in a highly conditional manner. How much force is transmitted between two contacting particles is always conditional not only on all the other forces acting between the particles in question but also on those acting on the other particles in the system. Broadly, we are interested in the nature and extent to which flows through a contact network favour certain pathways over others, and how the mechanisms that govern such biased flows for a given imposed loading history determine the future evolution of the contact network. Our first step is to solve a selection of fundamental combinatorial optimisation problems on the contact network from the perspective of force transmission. Here we report on solutions to the Maximum Flow Minimum Cost Problem for a weighted contact network where the weights assigned to the links of the contact network are varied according to their contact types. We found that those pathways through which the maximum flow of force is transmitted, in the direction of the maximum principal stress, at minimum cost - pass through the great majority of the force chains. Although the majority of the contacts in these pathways are elastic, the plastic contacts bear an undue influence on the minimum cost.

  13. Multigrid Implementation of Cellular Automata for Topology Optimisation of Continuum Structures with Design Dependent loads

    NARCIS (Netherlands)

    Zakhama, R.

    2009-01-01

    Topology optimisation of continuum structures has become mature enough to be often applied in industry and continues to attract the attention of researchers and software companies in various engineering fields. Traditionally, most available algorithms for solving topology optimisation problems are b

  14. Shape Optimisation of Holes in Loaded Plates by Minimisation of Multiple Stress Peaks

    Science.gov (United States)

    2015-04-01

    September, San Francisco , USA. Heller M, Burchill M, Wescott R, Waldman W, Kaye R, Evans R, McDonald M, 2009: Airframe life extension by optimised...9. TASK NUMBER AIR 07/283 10. TASK SPONSOR OIC- ASI -DGTA 11. NO. OF PAGES 123 12. NO. OF REFERENCES 35 13. DSTO PUBLICATIONS

  15. DC Motor Load Analysis and Cooling Consideration to Optimise the Power Consumption- Case Study

    Directory of Open Access Journals (Sweden)

    Mr. K.G. Bante

    2013-06-01

    Full Text Available The need of energy conservation is the increased requirement of all industries as the cost of the energy increasing day by day. DC motors have been the workhorse of variable speed drives in the continuous steel rolling mills for many years. DC motors in the steel rolling mills are usually separately ventilated by providing air blower, heat exchanger and water. Cooling air is circulated inside the motor by air blower. Water circulates through the heat exchanger and cools the air. Energy consumption by the air blower plays a vital role in optimizing the energy consumption. This article indicates that the loading pattern of the DC motor should decide the control strategy for effective and efficient cooling arrangement.

  16. Integration of part selection, machine loading and machining optimisation decisions for balanced workload in flexible manufacturing system

    Directory of Open Access Journals (Sweden)

    Mussa I. Mgwatu

    2011-10-01

    Full Text Available This paper demonstrates the importance of incorporating and solving the machining optimisation problem jointly with part selection and machine loading problems in order to avoid unbalanced workload in the FMS. Unbalanced workload renders to ineffective FMS such that some machines on the manufacturing shop floor become more occupied than others. Since CNC machine tools employed in the FMS are rather expensive, it is mostly important to balance the workload so that all machines can be effectively utilised. Therefore, in this study, two mathematical models are presented and solved in efforts to balance the workload and improve the performance of the FMS. A two-stage sequential approach is adopted whereby the first stage deals with the maximum throughput objective while the second stage deals with the minimum production cost objective. The results show that when part selection, machine loading and machining optimisation problems are jointly solved, more practical decisions can be made and a wide range of balanced workload in the FMS can be realised with minimum production cost objective. The results also show that the available machine time and tooling budget have enormous effects on throughput and production cost.

  17. CMP dummy pattern based on VSB writer load

    Science.gov (United States)

    Sakata, Wakahiko; Osawa, Isaku; Narukawa, Shogo; Takikawa, Tadahiko; Mohri, Hiroshi

    2010-05-01

    The load of VSB-EB mask writers has significantly increased since particularly RET/OPC and CMP dummy pattern generation technologies were widely adopted into designs at advanced nodes, with the result that the volume of mask data patterns was increased exponentially. In order to reduce the load of VSB mask writer, we've focused on CMP dummy patterns and developed a method of reducing CMP dummy pattern, which can smartly write CMP dummy patterns without not only deteriorating the CMP effects by them and also increasing the total number of the mask writer's shot count. To that end, we are aiming to establish a VSB-mask-writer-friendly CMP dummy pattern generation flow with CMP simulator developers by providing a mask writer parameter for them. This paper shows the first experimental results of our mask writer's load reduction work.

  18. Machine Learning of the Reactor Core Loading Pattern Critical Parameters

    Directory of Open Access Journals (Sweden)

    Krešimir Trontl

    2008-01-01

    Full Text Available The usual approach to loading pattern optimization involves high degree of engineering judgment, a set of heuristic rules, an optimization algorithm, and a computer code used for evaluating proposed loading patterns. The speed of the optimization process is highly dependent on the computer code used for the evaluation. In this paper, we investigate the applicability of a machine learning model which could be used for fast loading pattern evaluation. We employ a recently introduced machine learning technique, support vector regression (SVR, which is a data driven, kernel based, nonlinear modeling paradigm, in which model parameters are automatically determined by solving a quadratic optimization problem. The main objective of the work reported in this paper was to evaluate the possibility of applying SVR method for reactor core loading pattern modeling. We illustrate the performance of the solution and discuss its applicability, that is, complexity, speed, and accuracy.

  19. Preparation, optimisation and characterisation of novel wound healing film dressings loaded with streptomycin and diclofenac.

    Science.gov (United States)

    Pawar, H V; Tetteh, J; Boateng, J S

    2013-02-01

    Streptomycin (STP) and diclofenac (DLF) loaded film dressings were prepared by blending Polyox(®) (POL) with four hydrophilic polymers [hydroxypropylmethylcellulose (HPMC), carrageenan (CAR), sodium alginate (SA) or chitosan (CS)] using glycerol (GLY) as plasticiser. The films were characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, texture analysis (tensile and swelling characteristics) and in vitro dissolution profiles using Franz diffusion cell. SEM showed homogeneous morphology for both blank (BLK) and drug loaded (DL) films. Films prepared by blending of POL with the other polymers showed a reduction in the crystallisation of POL in descending order of SA>CS>HPMC>CAR respectively. DSC and XRD showed no crystalline peaks of STP and DLF suggesting molecular dispersion of both drugs as well as possible drug interaction with negatively charged sulphate ions present in CAR. The DL films did not show any IR bands of both drugs, confirming the DSC and XRD results. POL-CAR-BLK films showed higher tensile strength (12.32±1.40 MPa) than the POL-CAR-DL films (9.52±1.12 MPa). DL films plasticised with 25%w/w GLY revealed soft and tough (tensile strength 1.02±0.28 MPa, % elongation 1031.33±16.23) formulations. The swelling capacities of POL-CAR-BLK and POL-CAR-DL films were (733.17±25.78%) and (646.39±40.39%), increasing to (1072.71±80.30%) and (1051±86.68%) for POL-CAR-BLK-25% GLY and POL-CAR-DL-25% GLY respectively. POL-CAR-DL films showed significantly (n=3, p<0.0318) lower cumulative release of STP and DLF (52.11±1.34, 55.26±2.25) compared to POL-CAR-DL-25% GLY films (60.07±1.56, 63.39±1.92) respectively.

  20. Characteristics definition and optimisation of an integrated electromechanical battery under cyclic loading; Caracterisation et optimisation d'une batterie electromecanique sous chargement cyclique

    Energy Technology Data Exchange (ETDEWEB)

    Kerzreho, C.

    2002-01-15

    This work takes place into a multidisciplinary project, gathering mechanical and electromechanical specialists, with the aim to design a 3 kWh household electromechanical battery module. The energy is stored as kinetic one in a flywheel. The main characteristics of this battery are a high yield, a long life duration and a minimal discharge time over one hour. At a low cost, it could be used in conjunction with alternative electric sources and to secure and regulate home current supplies and consumption. Following a literature review of the available technologies, the flywheel similitude properties are demonstrated and capabilities design coefficients are defined taking into account the stress cycles. In order to define criterions to choose the flywheel material and geometry, the results are applied to the major literatures configurations including metals, composites or ceramics. They are brought together as graphical maps and, using optimal solution surfaces, they show the compromises between the design criterions such as specific energy, energy density, maximal rotational velocity and cost. A single suited structure is then defined which integrates into the flywheel some parts of the motor-generator and of the magnetic bearings. A global design process is conducted taking into account the specific properties and the interactions between the components. The geometry of the motor-generator rotor is optimised then, improving the battery performances. The feasibility of an auto-fitting process is proposed showing that endurance limit depends on flywheel slenderness. The build prototype is finally presented. (author)

  1. Capacitively Loaded Loop-Based Antennas with Reconfigurable Radiation Patterns

    Directory of Open Access Journals (Sweden)

    Saber Dakhli

    2015-01-01

    Full Text Available A class of metamaterial-inspired antennas having reconfigurable radiation patterns is proposed. They consist of a driven monopole antenna with one- and two-capacitively loaded loop (CLL, near field resonant parasitic elements. Two configurations are studied by considering the state of these CLL elements as being either open or closed configurations. Simulation results explain the design features and demonstrate that the structure can change its beam direction simply by controlling the switched states. Two prototypes with one- and two-CLL elements were fabricated and tested. The measured impedance mismatch and radiation pattern results are presented and compared to the corresponding simulated values.

  2. Demand Flexibility Time Intervals for Aggregate Residential Load Patterns

    OpenAIRE

    Sajjad, Intisar A.; CHICCO Gianfranco; Napoli, Roberto

    2015-01-01

    This paper deals with the definition of demand flexibility time intervals. These intervals are extracted from the binomial probability model of load variation patterns with the two possible categories of increase and non-increase in demand. These intervals along with the information on the coefficient of variation of the aggregate demand are used to assess the potential of demand flexibility exhibited by the aggregate residential demand in different periods of the day. The results of the prop...

  3. Aerosol loading impact on Asian monsoon precipitation patterns

    Science.gov (United States)

    Biondi, Riccardo; Cagnazzo, Chiara; Costabile, Francesca; Cairo, Francesco

    2017-04-01

    Solar light absorption by aerosols such as black carbon and dust assume a key role in driving the precipitation patterns in the Indian subcontinent. The aerosols stack up against the foothills of the Himalayas in the pre-monsoon season and several studies have already demonstrated that this can cause precipitation anomalies during summer. Despite its great significance in climate change studies, the link between absorbing aerosols loading and precipitation patterns remains highly uncertain. The main challenge for this kind of studies is to find consistent and reliable datasets. Several aerosol time series are available from satellite and ground based instruments and some precipitation datasets from satellite sensors, but they all have different time/spatial resolution and they use different assumptions for estimating the parameter of interest. We have used the aerosol estimations from the Ozone Monitoring Instrument (OMI), the Along-Track Scanning Radiometer (AATSR) and the MODerate resolution Imaging Spectroradiometer (MODIS) and validated them against the Aerosol Robotic Network (AERONET) measurements in the Indian area. The precipitation has been analyzed by using the Tropical Rainfall Measuring Mission (TRMM) estimations and the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). From our results it is evident the discrepancy between the aerosol loading on the area of interest from the OMI, AATSR, and MODIS, but even between 3 different algorithms applied to the MODIS data. This uncertainty does not allow to clearly distinguishing high aerosol loading years from low aerosol loading years except in a couple of cases where all the estimations agree. Similar issues are also present in the precipitation estimations from TRMM and MERRA-2. However, all the aerosol datasets agree in defining couples of consecutive years with a large gradient of aerosol loading. Based on this assumption we have compared the precipitation anomalies and

  4. [Economic impact of optimising antiretroviral treatment in human immunodeficiency virus-infected adults with suppressed viral load in Spain, by implementing the grade A-1 evidence recommendations of the 2015 GESIDA/National AIDS Plan].

    Science.gov (United States)

    Ribera, Esteban; Martínez-Sesmero, José Manuel; Sánchez-Rubio, Javier; Rubio, Rafael; Pasquau, Juan; Poveda, José Luis; Pérez-Mitru, Alejandro; Roldán, Celia; Hernández-Novoa, Beatriz

    2017-01-18

    The objective of this study is to estimate the economic impact associated with the optimisation of triple antiretroviral treatment (ART) in patients with undetectable viral load according to the recommendations from the GeSIDA/PNS (2015) Consensus and their applicability in the Spanish clinical practice. A pharmacoeconomic model was developed based on data from a National Hospital Prescription Survey on ART (2014) and the A-I evidence recommendations for the optimisation of ART from the GeSIDA/PNS (2015) consensus. The optimisation model took into account the willingness to optimise a particular regimen and other assumptions, and the results were validated by an expert panel in HIV infection (Infectious Disease Specialists and Hospital Pharmacists). The analysis was conducted from the NHS perspective, considering the annual wholesale price and accounting for deductions stated in the RD-Law 8/2010 and the VAT. The expert panel selected six optimisation strategies, and estimated that 10,863 (13.4%) of the 80,859 patients in Spain currently on triple ART, would be candidates to optimise their ART, leading to savings of €15.9M/year (2.4% of total triple ART drug cost). The most feasible strategies (>40% of patients candidates for optimisation, n=4,556) would be optimisations to ATV/r+3TC therapy. These would produce savings between €653 and €4,797 per patient per year depending on baseline triple ART. Implementation of the main optimisation strategies recommended in the GeSIDA/PNS (2015) Consensus into Spanish clinical practice would lead to considerable savings, especially those based in dual therapy with ATV/r+3TC, thus contributing to the control of pharmaceutical expenditure and NHS sustainability. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  5. Optimised Cockpit Heat Load Analysis using Skin Temperature Predicted by CFD and Validation by Thermal Mapping to Improve the Performance of Fighter Aircraft

    Directory of Open Access Journals (Sweden)

    Paresh Gupta

    2015-03-01

    Full Text Available Designing of optimum environmental control system (ECS plays a major role for increasing performance of fighter aircraft depending upon requirement of engine bleed air for running of ECS. Accurate estimation of cockpit skin temperature for obtaining optimised cockpit heat load helps in estimation of engine bleed air for ECS. Present research evolved a methodology for comparing the theoretically calculated skin temperature with computational fluid dynamics (CFD analysis to obtain optimum skin temperature. Results are validated by flight tests under critical flight conditions using thermal crayons. Based on which the optimized heat load and bleed air requirements has been computed. Uncertainty analysis of skin temperature measurement for thermal crayons have been undertaken. The results indicate that the theoretical skin temperature is -26.70 per cent as that of CFD estimated skin temperature. Optimized average cockpit heat load at critical flight profiles is 0.74 times the theoretical cockpit heat load, leading to reduction of bleed air requirement by 26 per cent as compared to theoretical. Due to this literature survey has pridicted the increase in performance parameters like increase in bleed air pressure by 78 per cent, increase in thrust by 60 per cent, and decrease in specific fuel consumption (SFC by 40 per cent to improve the endurance of aircraft. The research has generated governing equations for variation of cockpit heat loads w.r.t aircraft skin temperatures.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.12-24, DOI:http://dx.doi.org/10.14429/dsj.65.7200

  6. MTR core loading pattern optimization using burnup dependent group constants

    Directory of Open Access Journals (Sweden)

    Iqbal Masood

    2008-01-01

    Full Text Available A diffusion theory based MTR fuel management methodology has been developed for finding superior core loading patterns at any stage for MTR systems, keeping track of burnup of individual fuel assemblies throughout their history. It is based on using burnup dependent group constants obtained by the WIMS-D/4 computer code for standard fuel elements and control fuel elements. This methodology has been implemented in a computer program named BFMTR, which carries out detailed five group diffusion theory calculations using the CITATION code as a subroutine. The core-wide spatial flux and power profiles thus obtained are used for calculating the peak-to-average power and flux-ratios along with the available excess reactivity of the system. The fuel manager can use the BFMTR code for loading pattern optimization for maximizing the excess reactivity, keeping the peak-to-average power as well as flux-ratio within constraints. The results obtained by the BFMTR code have been found to be in good agreement with the corresponding experimental values for the equilibrium core of the Pakistan Research Reactor-1.

  7. Optimisation of ITER Nb3Sn CICCs for coupling loss, transverse electromagnetic load and axial thermal contraction

    CERN Document Server

    Nijhuis, A; Rolando, G

    2011-01-01

    The ITER cable-in-conduit conductors (CICCs) are built up from sub-cable bundles, wound in different stages, which are twisted to counter coupling loss caused by time-changing external magnet fields. The selection of the twist pitch lengths has major implications for the performance of the cable in the case of strain sensitive superconductors, i.e. Nb3Sn, as the electromagnetic and thermal contraction loads are large but also for the heat load from the AC coupling loss. Reduction of the transverse load and warm-up cool-down degradation can be reached by applying longer twist pitches in a particular sequence for the sub-stages, offering a large cable transverse stiffness, adequate axial flexibility and maximum allowed lateral strand support. Analysis of short sample (TF conductor) data reveals that increasing the twist pitch can lead to a gain of the effective axial compressive strain of more than 0.3 % with practically no degradation from bending. For reduction of the coupling loss, specific choices of the ca...

  8. Evolution of anthropoid jaw loading and kinematic patterns.

    Science.gov (United States)

    Ravosa, M J; Vinyard, C J; Gagnon, M; Islam, S A

    2000-08-01

    Major transformations in the skull and masticatory system characterized the evolution of crown anthropoids. To offer further insight into the phylogenetic and arguably adaptive significance of specific primate mandibular loading and kinematic patterns, allometric analyses of metric parameters linked to masticatory function are performed within and between 47 strepsirhine and 45 recent anthropoid species. When possible, basal anthropoids are considered. These results are subsequently integrated with prior experimental and morphological work on primate skull form. As compared to strepsirhines, crown anthropoids have a vertically longer ascending ramus linked to a glenoid and condyle positioned relatively higher above the occlusal plane. Interestingly, anthropoids and strepsirhines do not exhibit different mean ratios of condylar to glenoid height, which suggests that both clades are similar in their ability to evenly distribute occlusal contacts and perhaps forces along the postcanine teeth. Thus, given the considerable suborder differences in the scaling of both glenoid and condylar height, we argue that much of this variation in jaw-joint height is linked to suborder differences in relative facial height due in turn to increased encephalization, basicranial flexion, and facial kyphosis in anthropoids. Due to a more elongate ascending ramus, anthropoids evince more vertically oriented masseters than like-sized strepsirhines. Having a relatively longer ramus and a more medially displaced lateral pterygoid plate, crown anthropoids exhibit medial pterygoids oriented similar to those of strepsirhines, but with a variably longer lever arm. As anthropoid masseters are less advantageously placed to effect transverse movements/forces, we argue that balancing-side deep-masseter activity underlying a wishboning loading regime serves to increase, or at least maintain, transverse levels of jaw movement and occlusal force at the end of the masticatory power stroke. Crown

  9. Distinct loading conditions reveal various patterns of right ventricular adaptation

    NARCIS (Netherlands)

    Borgdorff, Marinus A. J.; Bartelds, Beatrijs; Dickinson, Michael G.; Steendijk, Paul; de Vroomen, Maartje; Berger, Rolf M. F.

    2013-01-01

    Right ventricular (RV) failure due to chronically abnormal loading is a main determinant of outcome in pulmonary hypertension (PH) and congenital heart disease. However, distinct types of RV loading have been associated with different outcomes. To determine whether the adaptive RV response depends o

  10. Biocompatible lidocaine and prilocaine loaded-nanoemulsion system for enhanced percutaneous absorption: QbD-based optimisation, dermatokinetics and in vivo evaluation.

    Science.gov (United States)

    Negi, Poonam; Singh, Bhupinder; Sharma, Gajanand; Beg, Sarwar; Katare, Om Prakash

    2015-01-01

    Barrier properties of the skin and physicochemical properties of the drugs are the main hiccups in delivering local anaesthetic molecules topically. The present work endeavours for systematic optimisation and evaluation of nanoemulsions (NEs) of local anaesthetic drugs, lidocaine and prilocaine, employing the systematic approach of Quality by Design. A 3(3) Box-Behnken design was employed for systematic optimisation of the factors obtained from screening studies employing Plackett-Burman design and risk assessment studies. The superior permeation rates, and higher concentrations of the drugs in skin layers from the optimised NE carriers, were achieved in permeation and dermatokinetic studies, when compared to marketed cream. Furthermore, rapid onset of action was demonstrated by the NE system in rabbit eye corneal reflex model and biocompatibility was confirmed from the absence of any marked skin change(s) in the normal skin histology. The developed NE systems demonstrated it as a promising carrier for topical delivery of lidocaine and prilocaine.

  11. Wounding patterns and human performance in knife attacks: optimising the protection provided by knife-resistant body armour

    OpenAIRE

    Bleetman, A; Watson, Celia H.; Horsfall, Ian; Champion, Steve M.

    2016-01-01

    Stab attacks generate high loads,1 and to defeat them, armour needs to be of a certain thickness and stiffness.2,3 Slash attacks produce much lower loads and armour designed to defeat them can be far lighter and more flexible.Methods and subjects: Phase 1: Human performance in slash attacks: 87 randomly selected students at the Royal Military College of Science were asked to make one slash attack with an instrumented blade on a vertically mounted target. No instructions on how to slash the...

  12. Landing pattern and vertical loading rates during first attempt of barefoot running in habitual shod runners.

    Science.gov (United States)

    Cheung, Roy T H; Rainbow, Michael J

    2014-04-01

    There is evidence supporting that habitual barefoot runners are able to disperse impact loading rates by landing pattern modification. Yet, case studies suggested that barefoot running may result in severe running injuries, such as metatarsal and calcaneal stress fractures. Injuries may be due to a difference in biomechanical response between habitual and novice barefoot runners. This study investigated the initial effects of barefoot running in habitual shod runners in terms of landing pattern modification and vertical loading rates. Thirty habitual shod runners (mean age 25.5±5.2years; 18 men; with a minimum running mileage of 30km per week for at least one year) ran on an instrumented treadmill at 10km/h shod and barefoot in a randomized order. Vertical average (VALR) and instantaneous loading rates (VILR) were obtained by established methods. Landing pattern was presented as a ratio between the number of footfalls with a heelstrike and the total step number. Twenty participants demonstrated an automatic transition to a non-heelstrike landing during barefoot running, whereas a mixed landing pattern was observed in 10 participants. Compared to shod running, both VALR and VILR were significantly reduced during barefoot running (pbarefoot running, regardless of the landing pattern. VALR for the non-heelstrike pattern during barefoot running was significantly lower than participants with a mixed landing pattern. Conversely, we observed two participants who completely altered their landing patterns, presented high VALR and VILR values. Habitual shod runners presented lower loading rates during barefoot running but their landing pattern transitions were not uniform. Novice barefoot runners with a mixed landing pattern may sustain higher loading rates, compared with those who completely avoided heelstrike pattern. However, a complete landing pattern modification may not guarantee lower loading rates.

  13. Optimisation of Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    H. El Hamchary

    1996-04-01

    Full Text Available When choosing the most appropriate microstrip antenna configuration for particular applications, the kind of excitation of the radiating element is an essential factor that requires careful considerations. For controlling the distribution of energy of the linear or planar array of elements and for coupling energy to the individual elements, a wide variety of feed mechanisms are available. In this paper, the coaxial antenna feeding is assumed and the best (optimised feeding is found. Then, antenna characteristics such as radiation pattern, return loss, input impedance, and VSWR are obtained.

  14. The muscle activation patterns of lower limb during stair climbing at different backpack load.

    Science.gov (United States)

    Yali, Han; Aiguo, Song; Haitao, Gao; Songqing, Zhu

    2015-01-01

    Stair climbing under backpack load condition is a challenging task. Understanding muscle activation patterns of lower limb during stair climbing with load furthers our understanding of the factors involved in joint pathology and the effects of treatment. At the same time, stair climbing under backpack load requires adjustments of muscle activations and increases joint moment compared to level walking, which with muscle activation patterns are altered as a result of using an assistive technology, such as a wearable exoskeleton leg for human walking power augmentation. Therefore, the aim of this study was to analyze lower limb muscles during stair climbing under different backpack load. Nine healthy volunteers ascended a four-step staircase at different backpack load (0 kg, 10 kg, 20 kg, 30 kg). Electromyographic (EMG) signals were recorded from four lower limb muscles (gastrocnemius, tibialis anterior, hamstring, rectus femoris). The results showed that muscle activation amplitudes of lower limb increase with increasing load during stair climbing, the maximum RMS of gastrocnemius are greater than tibialis anterior, hamstring and rectus femoris whether stair climbing or level walking under the same load condition. However, the maximum RMS of hamstring are smaller than gastrocnemius, tibialis anterior and rectus femoris. The study of muscle activation under different backpack load during stair climbing can be used to design biomechanism and explore intelligent control based on EMG for a wearable exoskeleton leg for human walking power augmentation.

  15. Influences of load pattern selection and higher modes on pushover analysis for R.C. structures

    Institute of Scientific and Technical Information of China (English)

    HOU Shuang; OU Jin-ping

    2008-01-01

    Load pattern selection is one of the critical issues in pushover analysis (POA) when the influence of higher modes is evident. In terms of interstory drift, comparisons between the nonlinear time history analysis (NL-THA) and the pushover analysis (POA) were conducted for three typical RC frame buildings under a va-riety of ground motion levels. Eight typical earthquake inputs, including four earthquake records and four artifi-cial earthquake waves, were employed as the input of NL-THA; five typical lateral load patterns were consid-ered in POA. By means of modal participation factor, the higher mode effect in POA was quantified considering floor numbers and the ground motion intensity. Suggestions about load pattern selection in POA were provided when higher mode influence was found evident.

  16. Parameter uncertainty-based pattern identification and optimization for robust decision making on watershed load reduction

    Science.gov (United States)

    Jiang, Qingsong; Su, Han; Liu, Yong; Zou, Rui; Ye, Rui; Guo, Huaicheng

    2017-04-01

    Nutrients loading reduction in watershed is essential for lake restoration from eutrophication. The efficient and optimal decision-making on loading reduction is generally based on water quality modeling and the quantitative identification of nutrient sources at the watershed scale. The modeling process is influenced inevitably by inherent uncertainties, especially by uncertain parameters due to equifinality. Therefore, the emerging question is: if there is parameter uncertainty, how to ensure the robustness of the optimal decisions? Based on simulation-optimization models, an integrated approach of pattern identification and analysis of robustness was proposed in this study that focuses on the impact of parameter uncertainty in water quality modeling. Here the pattern represents the discernable regularity of solutions for load reduction under multiple parameter sets. Pattern identification is achieved by using a hybrid clustering analysis (i.e., Ward-Hierarchical and K-means), which was flexible and efficient in analyzing Lake Bali near the Yangtze River in China. The results demonstrated that urban domestic nutrient load is the most potential source that should be reduced, and there are two patterns for Total Nitrogen (TN) reduction and three patterns for Total Phosphorus (TP) reduction. The patterns indicated different total reduction of nutrient loads, which reflect diverse decision preferences. The robust solution was identified by the highest accomplishment with the water quality at monitoring stations that were improved uniformly with this solution. We conducted a process analysis of robust decision-making that was based on pattern identification and uncertainty, which provides effective support for decision-making with preference under uncertainty.

  17. Electromyographic and Neuromuscular Force Patterns Associated with Unexpectedly Loaded Rapid Limb Movements.

    Science.gov (United States)

    Richardson, Charles; Simmons, Roger W.

    Bi-articular, unidirectional arm movements were studied to evaluate the electromyographic (EMG) and neuromuscular force patterns that occur when a limb is unexpectedly perturbed. A series of training trials were continued with a control load spring attached to the apparatus until a pre-specified criterion for learning was attained. The limb was…

  18. Chemotherapy affects the pattern of failure after shear loading of the proximal tibial growth plate.

    NARCIS (Netherlands)

    Leeuwen, B.L.; Hartel, R.M.; Jansen, H.W.B.; Verkerke, G.J.; Veth, R.P.H.; Kamps, W.A.; Hoekstra, H.J.

    2004-01-01

    INTRODUCTION: Tibial bones are shorter and less resistant to shear forces after treatment with doxorubicin, methotrexate, or cisplatin. We investigated the pattern of failure after shear loading of the proximal tibial growth plate in rats treated with these chemotherapeutic agents. MATERIALS AND MET

  19. The influence of impact direction and axial loading on the bone fracture pattern.

    Science.gov (United States)

    Cohen, Haim; Kugel, Chen; May, Hila; Medlej, Bahaa; Stein, Dan; Slon, Viviane; Brosh, Tamar; Hershkovitz, Israel

    2017-08-01

    The effect of the direction of the impact and the presence of axial loading on fracture patterns have not yet been established in experimental 3-point bending studies. To reveal the association between the direction of the force and the fracture pattern, with and without axial loading. A Dynatup Model POE 2000 (Instron Co.) low energy pendulum impact machine was utilized to apply impact loading on fresh pig femoral bones (n=50). The bone clamp shaft was adjusted to position the bone for three-point bending with and without additional bone compression. Four different directions of the force were applied: anterior, posterior, lateral, and medial. The impacted aspect can be distinguished from the non-impacted aspects based on the fracture pattern alone (the most fractured one); the impact point can be identified on bare bones (the area from which all oblique lines radiate and/or the presence of a chip fragment). None of our experiments (with and without compression) yielded a "true" butterfly fracture, but instead, oblique radiating lines emerged from the point of impact (also known as "false" butterfly). Impacts on the lateral and anterior aspects of the bones produce more and longer fracture lines than impacts on the contralateral side; bones subjected to an impact with axial loading are significantly more comminuted and fragmented. Under axial loading, the number of fracture lines is independent of the impact direction. Our study presents an experimental model for fracture analysis and shows that the impact direction and the presence of axial loading during impact significantly affect the fracture pattern obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Dynamical prediction and pattern mapping in short-term load forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, Luis Antonio; Rodrigues, Daniela D.; Lima, Silvio T. [Departamento de Engenharia Eletronica, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG (Brazil); Martinez, Carlos Barreira [Departamento de Engenharia Hidraulica e Recursos Hidricos, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, MG (Brazil)

    2008-01-15

    This work will not put forward yet another scheme for short-term load forecasting but rather will provide evidences that may improve our understanding about fundamental issues which underlay load forecasting problems. In particular, load forecasting will be decomposed into two main problems, namely dynamical prediction and pattern mapping. It is argued that whereas the latter is essentially static and becomes nonlinear when weekly features in the data are taken into account, the former might not be deterministic at all. In such cases there is no determinism (serial correlations) in the data apart from the average cycle and the best a model can do is to perform pattern mapping. Moreover, when there is determinism in addition to the average cycle, the underlying dynamics are sometimes linear, in which case there is no need to resort to nonlinear models to perform dynamical prediction. Such conclusions were confirmed using real load data and surrogate data analysis. In a sense, the paper details and organizes some general beliefs found in the literature on load forecasting. This sheds some light on real model-building and forecasting problems and helps understand some apparently conflicting results reported in the literature. (author)

  1. Optimising Code Generation with haggies

    OpenAIRE

    Reiter, Thomas

    2009-01-01

    This article describes haggies, a program for the generation of optimised programs for the efficient numerical evaluation of mathematical expressions. It uses a multivariate Horner-scheme and Common Subexpression Elimination to reduce the overall number of operations. The package can serve as a back-end for virtually any general purpose computer algebra program. Built-in type inference that allows to deal with non-standard data types in strongly typed languages and a very flexible, pattern-ba...

  2. A Simplified Short Term Load Forecasting Method Based on Sequential Patterns

    DEFF Research Database (Denmark)

    Kouzelis, Konstantinos; Bak-Jensen, Birgitte; Mahat, Pukar

    2014-01-01

    , require considerable expertise for model construction and re-construction. Consequently, they might be impractical to use in case multiple regional forecasts are to be conducted. In this perspective, a simplified hour-ahead load forecasting algorithm was created so as to provide an automated approach...... to the problem as an alternative to other established forecasting techniques. This algorithm is based on sequential patterns and, hence, the continuous data are discretized in order to compare recent to past patterns. Although some error due to discretization is introduced, the method performs adequately well...... in comparison with an ARIMA model....

  3. Load Distribution Patterns for Displacement-based Seismic Design of RC Framed Buildings

    Science.gov (United States)

    Varughese, Jiji Anna; Menon, Devdas; Meher Prasad, A.

    2014-12-01

    The behaviour of tall frames is characterized by the influence of higher modes in addition to the fundamental mode and thus the design procedures for Displacement-based Design (DBD) adopt several measures to control higher mode effects. The performances of 4, 9 and 15-storeyed frames, designed by DBD were verified using non-linear time history analyses. Higher values of inter-storey drift and damage index were seen near the top of tall frames, which shows the inefficiency of the design method in accounting for higher mode effect. As the principle of damage-limiting aseismic design is to get uniform damage along the height of the frame, several load distribution patterns were examined and the storey shear distributions were compared to identify the best pattern to get uniform damage. The Chao load distribution was found to give higher storey shear at top and thus the frames were redesigned using this load distribution. The efficiency of Chao load distribution in reducing higher mode effects is demonstrated using non-linear time history analyses.

  4. Advanced and flexible genetic algorithms for BWR fuel loading pattern optimization

    Energy Technology Data Exchange (ETDEWEB)

    Martin-del-Campo, Cecilia [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, Jiutepec, Mor., 62550 (Mexico)], E-mail: cmcm@fi-b.unam.mx; Palomera-Perez, Miguel-Angel [Instituto de Investigaciones en Matematicas Aplicadas y Sistemas, Universidad Nacional Autonoma de Mexico, Circuito Escolar, Ciudad Universitaria, 04510 DF (Mexico)], E-mail: mapp@uxmcc2.iimas.unam.mx; Francois, Juan-Luis [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, Jiutepec, Mor., 62550 (Mexico)], E-mail: jlfl@fi-b.unam.mx

    2009-10-15

    This work proposes advances in the implementation of a flexible genetic algorithm (GA) for fuel loading pattern optimization for Boiling Water Reactors (BWRs). In order to avoid specific implementations of genetic operators and to obtain a more flexible treatment, a binary representation of the solution was implemented; this representation had to take into account that a little change in the genotype must correspond to a little change in the phenotype. An identifier number is assigned to each assembly by means of a Gray Code of 7 bits and the solution (the loading pattern) is represented by a binary chain of 777 bits of length. Another important contribution is the use of a Fitness Function which includes a Heuristic Function and an Objective Function. The Heuristic Function which is defined to give flexibility on the application of a set of positioning rules based on knowledge, and the Objective Function that contains all the parameters which qualify the neutronic and thermal hydraulic performances of each loading pattern. Experimental results illustrating the effectiveness and flexibility of this optimization algorithm are presented and discussed.

  5. Computer Based Optimisation Rutines

    DEFF Research Database (Denmark)

    Dragsted, Birgitte; Olsen, Flemmming Ove

    1996-01-01

    In this paper the need for optimisation methods for the laser cutting process has been identified as three different situations. Demands on the optimisation methods for these situations are presented, and one method for each situation is suggested. The adaptation and implementation of the methods...

  6. Computer Based Optimisation Rutines

    DEFF Research Database (Denmark)

    Dragsted, Birgitte; Olsen, Flemmming Ove

    1996-01-01

    In this paper the need for optimisation methods for the laser cutting process has been identified as three different situations. Demands on the optimisation methods for these situations are presented, and one method for each situation is suggested. The adaptation and implementation of the methods...

  7. Optimal optimisation in chemometrics

    NARCIS (Netherlands)

    Hageman, Joseph Albert

    2004-01-01

    The use of global optimisation methods is not straightforward, especially for the more difficult optimisation problems. Solutions have to be found for items such as the evaluation function, representation, step function and meta-parameters, before any useful results can be obtained. This thesis aims

  8. Simple models of district heating systems for load and demand side management and operational optimisation; Simple modeller for fjernvarmesystemer med henblik pae belastningsudjaevning og driftsoptimering

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, B. [Technical Univ. of Denmark, Dept. of Mechanical Engineering, Kgs. Lyngby (Denmark); Larsen, H.V. [Risoe National Lab., System Analysis Dept., Roskilde (DK)

    2004-12-01

    The purpose of this research project has been to further develop and test simple (aggregated) models of district heating (DH) systems for simulation and operational optimization, and to investigate the influence of Load Management and Demand Side Management (DMS) on the total operational costs. The work is based on physical-mathematical modelling and simulation of DH systems, and is a continuation of previous EFP-96 work. In the present EFP-2001 project the goals have been to improve the Danish method of aggregation by addressing the problem of aggregation of pressure losses, and to test the methods on a much larger data set than in the EFP-1996 project. In order to verify the models it is crucial to have good data at disposal. Full information on the heat loads and temperatures not only at the DH plant but also at every consumer (building) is needed, and therefore only a few DH systems in Denmark can supply such data. (BA)

  9. Impact of Thresholds and Load Patterns when Executing HPC Applications with Cloud Elasticity

    Directory of Open Access Journals (Sweden)

    Vinicius Facco Rodrigues

    2016-04-01

    Full Text Available Elasticity is one of the most known capabilities related to cloud computing, being largely deployed reactively using thresholds. In this way, maximum and minimum limits are used to drive resource allocation and deallocation actions, leading to the following problem statements: How can cloud users set the threshold values to enable elasticity in their cloud applications? And what is the impact of the application’s load pattern in the elasticity? This article tries to answer these questions for iterative high performance computing applications, showing the impact of both thresholds and load patterns on application performance and resource consumption. To accomplish this, we developed a reactive and PaaS-based elasticity model called AutoElastic and employed it over a private cloud to execute a numerical integration application. Here, we are presenting an analysis of best practices and possible optimizations regarding the elasticity and HPC pair. Considering the results, we observed that the maximum threshold influences the application time more than the minimum one. We concluded that threshold values close to 100% of CPU load are directly related to a weaker reactivity, postponing resource reconfiguration when its activation in advance could be pertinent for reducing the application runtime.

  10. Loading Patterns of the Posterior Cruciate Ligament in the Healthy Knee: A Systematic Review

    Science.gov (United States)

    List, Renate; Oberhofer, Katja; Fucentese, Sandro F.; Snedeker, Jess G.; Taylor, William R.

    2016-01-01

    Background The posterior cruciate ligament (PCL) is the strongest ligament of the knee, serving as one of the major passive stabilizers of the tibio-femoral joint. However, despite a number of experimental and modelling approaches to understand the kinematics and kinetics of the ligament, the normal loading conditions of the PCL and its functional bundles are still controversially discussed. Objectives This study aimed to generate science-based evidence for understanding the functional loading of the PCL, including the anterolateral and posteromedial bundles, in the healthy knee joint through systematic review and statistical analysis of the literature. Data sources MEDLINE, EMBASE and CENTRAL Eligibility criteria for selecting studies Databases were searched for articles containing any numerical strain or force data on the healthy PCL and its functional bundles. Studied activities were as follows: passive flexion, flexion under 100N and 134N posterior tibial load, walking, stair ascent and descent, body-weight squatting and forward lunge. Method Statistical analysis was performed on the reported load data, which was weighted according to the number of knees tested to extract average strain and force trends of the PCL and identify deviations from the norms. Results From the 3577 articles retrieved by the initial electronic search, only 66 met all inclusion criteria. The results obtained by aggregating data reported in the eligible studies indicate that the loading patterns of the PCL vary with activity type, knee flexion angle, but importantly also the technique used for assessment. Moreover, different fibres of the PCL exhibit different strain patterns during knee flexion, with higher strain magnitudes reported in the anterolateral bundle. While during passive flexion the posteromedial bundle is either lax or very slightly elongated, it experiences higher strain levels during forward lunge and has a synergetic relationship with the anterolateral bundle. The strain

  11. Detection of load application onto an optical fiber through changes in speckle patterns in an output light spot

    Science.gov (United States)

    Hasegawa, Makoto; Takeda, Ryo; Fujioka, Yuki

    2016-10-01

    For the purpose of investigating possibilities of utilizing, for sensing application, changes in speckle patterns to be observed in an output light spot from an optical fiber due to external disturbance, a certain level of load was applied onto an optical fiber through which laser beams emitted from a laser diode were propagating, and changes in the speckle patterns in the output light spot were investigated. In order to realize effective load application onto the optical fiber, a load application section was provided in which several ridges were intentionally provided onto opposite flat plates. A jacket-covered communication-grade multi-mode glass optical fiber was placed in the load application section so that corrugated bending of the fiber was intentionally induced via load application due to the ridges. A PV cell panel was irradiated with the output light spot from the optical fiber containing the speckle patterns therein. When weights were placed in the load application section, an output voltage from the PV cell panel was changed, indicating that the load application onto the optical fiber can be detected with this detection setup. Removal of the once-placed weights was also detected via changes in the PV cell panel output. Then, the load application onto the optical fiber and its removal was successfully detected via turn-on/off operations of an LED which was controlled in accordance with the changes in the output voltage level from the PV cell panel, in other words, through the changes in the speckle patterns.

  12. The effect of motion patterns on edge-loading of metal-on-metal hip resurfacing.

    Science.gov (United States)

    Mellon, S J; Kwon, Y-M; Glyn-Jones, S; Murray, D W; Gill, H S

    2011-12-01

    The occurrence of pseudotumours (soft tissue masses relating to the hip joint) following metal-on-metal hip resurfacing arthroplasty (MoMHRA) has been associated with high serum metal ion levels and consequently higher than normal bearing wear. We investigated the relationship between serum metal ion levels and contact stress on the acetabular component of MoMHRA patients for two functional activities; gait and stair descent. Four subjects with MoMHRA, who had their serum metal ion levels measured, underwent motion analysis followed by CT scanning. Their motion capture data was combined with published hip contact forces and finite element models representing 14% (peak force) and 60% (end of stance) of the gait cycle and 52% (peak force) of stair descent activity were created. The inclination angle of the acetabular component was increased by 10° in 1° intervals and the contact stresses were determined at each interval for each subject. When the inclination angle was altered in such a way as to cause the hip contact force to pass through the edge of the acetabular component edge-loading occurred. Edge-loading increased the contact stress by at least 50%; the maximum increase was 108%. Patients with low serum metal ion levels showed no increase in contact stress at peak force during gait or stair descent. Patients with high serum metal ion levels exhibited edge-loading with an increase to the inclination angle of their acetabular components. The increase in inclination angle that induced edge-loading for these subjects was less than the inter-subject variability in the angle of published hip contact forces. The results of this study suggest that high serum metal ion levels are the result of inclination angle influenced edge-loading but that edge-loading cannot be attributed to inclination angle alone and that an individual's activity patterns can reduce or even override the influence of a steep acetabular component and prevent edge-loading. Copyright © 2011 IPEM

  13. Isogeometric design optimisation

    NARCIS (Netherlands)

    Nagy, A.P.

    2011-01-01

    Design optimisation is of paramount importance in most engineering, e.g. aeronautical, automotive, or naval, disciplines. Its interdisciplinary character is manifested in the synthesis of geometric modelling, numerical analysis, mathematical programming, and computer sciences. The evolution of the f

  14. Optimisation of the LHCb detector

    CERN Document Server

    Hierck, R

    2003-01-01

    This thesis describes a comparison of the LHCb classic and LHCb light concept from a tracking perspective. The comparison includes the detector occupancies, the various pattern recognition algorithms and the reconstruction performance. The final optimised LHCb setup is used to study the physics performance of LHCb for the Bs->DsK and Bs->DsPi decay channels. This includes both the event selection and a study of the sensitivity for the Bs oscillation frequency, delta m_s, the Bs lifetime difference, DGamma_s, and the CP parameter gamma-2delta gamma.

  15. Optimisation of the LHCb detector

    CERN Document Server

    Hierck, R H

    2003-01-01

    This thesis describes a comparison of the LHCb classic and LHCb light concept from a tracking perspective. The comparison includes the detector occupancies, the various pattern recognition algorithms and the reconstruction performance. The final optimised LHCb setup is used to study the physics performance of LHCb for the Bs->DsK and Bs->DsPi decay channels. This includes both the event selection and a study of the sensitivity for the Bs oscillation frequency, delta m_s, the Bs lifetime difference, DGamma_s, and the CP parameter gamma-2delta gamma.

  16. Study of power load pattern on EAST divertor using PFCFlux code

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bin, E-mail: binzhang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Firdaouss, Mehdi [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Gong, Xianzu [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Ekedahl, Annika [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Peng, Xuebing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhang, Xiaodong, E-mail: xdzhang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2016-06-15

    Highlights: • This paper demonstrates the modeling result of power load pattern on EAST graphite divertor by using the PFCFlux code. • The grazing angle varies both poloidally and toroidally, changing by half a degree over the distance of 50 mm away from the strike point. • The correlation between both grazing angle and flux expansion and the magnetic equilibrium parameters are found by using the linear regression method. • The modeling result indicates that the edges of graphite tiles of EAST divertor are perfectly shadowed. - Abstract: The power load pattern on an EAST divertor component, spanning six tiles in the poloidal direction, has been studied with the PFCFlux code. A total of 49 different EAST plasma equilibria in lower single null configuration are used in the study. It is found that the incidence angle, or grazing angle, varies both toroidally and poloidally on the target, changing by approximately half a degree over a distance of 50 mm from the strike point. Strong correlations between the triangularity of the magnetic equilibrium and both the grazing angle and the flux expansion are found by using linear regression. A smaller value of triangularity gives wider plasma-wetted region on the target in lower-outer configuration, and a narrower plasma-wetted region in lower-inner configuration.

  17. Optimisation of digester performance with increasing organic loading rate for mono- and co-digestion of grass silage and dairy slurry.

    Science.gov (United States)

    Wall, David M; Allen, Eoin; Straccialini, Barbara; O'Kiely, Padraig; Murphy, Jerry D

    2014-12-01

    This study investigated the feasibility of mono-digesting grass silage, dairy slurry and the co-digestion of the two substrates at a range of concentrations with a specific focus on digester performance while increasing organic loading rate (OLR). The results show that the higher the proportion of grass silage in the substrate mix the higher the specific methane yield (SMY) achieved. Optimum conditions were assessed for 100% grass silage at an OLR of 3.5 kg VS m(-3) d(-1) generating a SMY of 398 L CH4 kg(-1) VS equating to a biomethane efficiency of 1.0. For co-digestion of grass silage with 20% dairy slurry the optimum condition was noted at an OLR of 4.0 kg VS m(-3) d(-1) generating a SMY of 349L CH4 kg(-1) VS and a biomethane efficiency of 1.01. Hydraulic retention times of less than 20 days proved to be a limiting factor in the operation of farm digesters.

  18. Changes in running pattern due to fatigue and cognitive load in orienteering.

    Science.gov (United States)

    Millet, Guillaume Y; Divert, Caroline; Banizette, Marion; Morin, Jean-Benoit

    2010-01-01

    The aim of this study was to examine the influence of fatigue on running biomechanics in normal running, in normal running with a cognitive task, and in running while map reading. Nineteen international and less experienced orienteers performed a fatiguing running exercise of duration and intensity similar to a classic distance orienteering race on an instrumented treadmill while performing mental arithmetic, an orienteering simulation, and control running at regular intervals. Two-way repeated-measures analysis of variance did not reveal any significant difference between mental arithmetic and control running for any of the kinematic and kinetic parameters analysed eight times over the fatiguing protocol. However, these parameters were systematically different between the orienteering simulation and the other two conditions (mental arithmetic and control running). The adaptations in orienteering simulation running were significantly more pronounced in the elite group when step frequency, peak vertical ground reaction force, vertical stiffness, and maximal downward displacement of the centre of mass during contact were considered. The effects of fatigue on running biomechanics depended on whether the orienteers read their map or ran normally. It is concluded that adding a cognitive load does not modify running patterns. Therefore, all changes in running pattern observed during the orienteering simulation, particularly in elite orienteers, are the result of adaptations to enable efficient map reading and/or potentially prevent injuries. Finally, running patterns are not affected to the same extent by fatigue when a map reading task is added.

  19. Investigation of journal orbit and flow pattern in a dynamically loaded journal bearing

    DEFF Research Database (Denmark)

    Christiansen, Christian Kim; Walther, Jens Honore; Klit, Peder

    2017-01-01

    A hydrodynamic journal bearing has been investigated using both the traditional two-dimensional (2D) Reynolds equation, and the full solution being the three-dimensional (3D) Navier-Stokes equations. The two approaches are compared by performing an investigation of two inlet groove designs......: the axial and the circumferential groove, respectively, on a bearing with length-to-diameter ratio of 0.5 exposed to a sinusoidal load pattern. Pressure distributions, journal orbits and frictional losses are compared. The modelling of grooves by pressure boundary conditions versus geometric conditions...... is examined. It is investigated if the presence of a groove increases frictional losses and the increase relates to groove dimensions. Furthermore, the influence of the groove design on the flow field is studied using the 3D solution....

  20. Cognitive load and autonomic response patterns under negative priming demand in depersonalization-derealization disorder.

    Science.gov (United States)

    Lemche, Erwin; Sierra-Siegert, Mauricio; David, Anthony S; Phillips, Mary L; Gasston, David; Williams, Steven C R; Giampietro, Vincent P

    2016-04-01

    Previous studies have yielded evidence for cognitive processing abnormalities and alterations of autonomic functioning in depersonalization-derealization disorder (DPRD). However, multimodal neuroimaging and psychophysiology studies have not yet been conducted to test for functional and effective connectivity under cognitive stress in patients with DPRD. DPRD and non-referred control subjects underwent a combined Stroop/negative priming task, and the neural correlates of Stroop interference effect, negative priming effect, error rates, cognitive load span and average amplitude of skin conductance responses were ascertained for both groups. Evoked haemodynamic responses for basic Stroop/negative priming activations were compared. For basic Stroop to neutral contrast, patients with DPRD differed in the location (inferior vs. superior lobule) of the parietal region involved, but showed similar activations in the left frontal region. In addition, patients with DPRD also co-activated the dorsomedial prefrontal cortex (BA9) and posterior cingulate cortex (BA31), which were also found to be the main between-group difference regions. These regions furthermore showed connectivity with frequency of depersonalization states. Evoked haemodynamic responses drawn from regions of interest indicated significant between-group differences in 30-40% of time points. Brain-behaviour correlations differed mainly in laterality, yet only slightly in regions. A reversal of autonomic patterning became evident in patients with DPRD for cognitive load spans, indicating less effective arousal suppression under cognitive stress - patients with DPRD showed positive associations of cognitive load with autonomic responses, whereas controls exhibit respective inverse association. Overall, the results of the present study show only minor executive cognitive peculiarities, but further support the notion of abnormalities in autonomic functioning in patients with DPRD.

  1. Automatic boiling water reactor loading pattern design using ant colony optimization algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.-D. [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2 Kuang Fu Road, Hsinchu 30013, Taiwan (China); Nuclear Engineering Division, Institute of Nuclear Energy Research, No. 1000, Wenhua Rd., Jiaan Village, Longtan Township, Taoyuan County 32546, Taiwan (China)], E-mail: jdwang@iner.gov.tw; Lin Chaung [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2 Kuang Fu Road, Hsinchu 30013, Taiwan (China)

    2009-08-15

    An automatic boiling water reactor (BWR) loading pattern (LP) design methodology was developed using the rank-based ant system (RAS), which is a variant of the ant colony optimization (ACO) algorithm. To reduce design complexity, only the fuel assemblies (FAs) of one eight-core positions were determined using the RAS algorithm, and then the corresponding FAs were loaded into the other parts of the core. Heuristic information was adopted to exclude the selection of the inappropriate FAs which will reduce search space, and thus, the computation time. When the LP was determined, Haling cycle length, beginning of cycle (BOC) shutdown margin (SDM), and Haling end of cycle (EOC) maximum fraction of limit for critical power ratio (MFLCPR) were calculated using SIMULATE-3 code, which were used to evaluate the LP for updating pheromone of RAS. The developed design methodology was demonstrated using FAs of a reference cycle of the BWR6 nuclear power plant. The results show that, the designed LP can be obtained within reasonable computation time, and has a longer cycle length than that of the original design.

  2. Influence of a training session on postural stability and foot loading patterns in soccer players

    Directory of Open Access Journals (Sweden)

    Vanessa K.N. Petry

    2016-03-01

    Full Text Available Sport specific movements coming along with characteristic plantar pressure distribution and a fatigue of muscles result in an increasing postural sway and therefore lead to a decrease in balance control. Although single soccer specific movements were expatiated with respect to these parameters, no information is available for a complete training session. The objective of the present observational study was to analyze the direct influence of soccer training on postural stability and gait patterns and whether or not these outcomes were altered by age. One hundred and eighteen experienced soccer players participated in the study and were divided into two groups. Group 1 contained 64 soccer players (age 13.31±0.66 years and Group 2 contains 54 ones (age 16.74±0.73 years. Postural stability, static plantar pressure distribution and dynamic foot loading patterns were measured. Our results showed that the soccer training session, as well as the age, has relevant influence on postural stability, while the age only (excluding the training has an influence on static plantar pressure distribution. The parameters of dynamic assessment seem therefore to be affected by age, training and a combination of both. Training and young age correlate with a decreased postural stability; they lead to a significant increase of peak pressure in the previously most loaded areas, and, after reaching a certain age and magnitude of absolute values, to a change in terminal stance and preswing phase of the roll-over. Moreover, younger players show an inhomogenous static plantar pressure distribution which might be the result of the decreased postural control in the young age.

  3. Simulation versus Optimisation

    DEFF Research Database (Denmark)

    Lund, Henrik; Arler, Finn; Østergaard, Poul Alberg

    2017-01-01

    investment optimisation or optimal solutions approach. On the other hand the analytical simulation or alternatives assessment approach. Awareness of the dissimilar theoretical assumption behind the models clarifies differences between the models, explains dissimilarities in results, and provides...... a theoretical and methodological foundation for understanding and interpreting results from the two archetypes. Keywords: energy system analysis; investment optimisation models; simulations models; modelling theory;renewable energy......In recent years, several tools and models have been developed and used for the design and analysis of future national energy systems. Many of these models focus on the integration of various renewable energy resources and the transformation of existing fossil-based energy systems into future...

  4. Optimising AspectJ

    DEFF Research Database (Denmark)

    Avgustinov, Pavel; Christensen, Aske Simon; Hendren, Laurie

    2005-01-01

    AspectJ, an aspect-oriented extension of Java, is becoming increasingly popular. However, not much work has been directed at optimising compilers for AspectJ. Optimising AOP languages provides many new and interesting challenges for compiler writers, and this paper identifies and addresses three...... all of the techniques in this paper in abc, our AspectBench Compiler for AspectJ, and we demonstrate significant speedups with empirical results. Some of our techniques have already been integrated into the production AspectJ compiler, ajc 1.2.1....

  5. The Pattern as a Reusable Component to Adaptive Framework for Load Balancing Mobile Agent in Internet Banking

    Directory of Open Access Journals (Sweden)

    A. Meiappane

    2012-03-01

    Full Text Available In recent years, the Software Architecture (SA of an Internet banking has become one of the most challengeable and risky fields of modern technology. The advent of the Internet has revolutionized the way banking is being done. In Internet banking, we analyzed some attributes such as usage, security, availability, load balancing and so on. Among those attributes Load Balancing is a serious problem in the Internet and it is necessary to build new systems incorporating load balancing as integral part of their design. The use of patterns, which is of a reusable component, is a good tool to help designers build load balancing systems. In this paper we are going to propose cluster load balancing technique by using mobile agent.

  6. Optimising Magnetostatic Assemblies

    DEFF Research Database (Denmark)

    Insinga, Andrea Roberto; Smith, Anders

    the optimal remanence distribution with respect to a linear objective functional. Additionally, it is shown here that the same formalism can be applied to the optimisation of the geometry of magnetic systems. Specifically, the border separating the permanent magnet from regions occupied by air or soft...

  7. Performance evaluation of PSO and GA in PWR core loading pattern optimization

    Energy Technology Data Exchange (ETDEWEB)

    Khoshahval, F., E-mail: f_khoshahval@sbu.ac.i [Engineering Department, Shahid Beheshti University, G.C., P.O. Box 1983963113, Velenjak, Tehran (Iran, Islamic Republic of); Minuchehr, H. [Engineering Department, Shahid Beheshti University, G.C., P.O. Box 1983963113, Velenjak, Tehran (Iran, Islamic Republic of); Zolfaghari, A., E-mail: a-zolfaghari@sbu.ac.i [Engineering Department, Shahid Beheshti University, G.C., P.O. Box 1983963113, Velenjak, Tehran (Iran, Islamic Republic of)

    2011-03-15

    Research highlights: The performance of both GA and PSO methods in optimizing of a PWR core are adequate. It seems GA arrives to its final parameter value in a fewer generation than the PSO. The computation time for GA is higher than PSO. The GA-2 and PSO-CFA algorithms perform better in comparison to GA-1 and PSO-IWA. - Abstract: The efficient operation and fuel management of PWRs are of utmost importance. Recently, genetic algorithm (GA) and particle swarm optimization (PSO) techniques have attracted considerable attention among various modern heuristic optimization techniques. GA is a powerful optimization technique, based upon the principles of natural selection and species evolution. GA is finding popularity as design tools because of its versatility, intuitiveness and ability to solve highly non-linear, mixed integer optimization problems. PSO refers to a relatively new family of algorithms and is mainly inspired by social behavior patterns of organisms that live within large group. This study addresses the application and performance comparison of PSO and GA optimization methods for nuclear fuel loading pattern problem. Flattening of power inside the reactor core of Bushehr nuclear power plant (WWER-1000 type) is chosen as an objective function to prove the validity of algorithms. In addition the performance of both optimization techniques in terms of convergence rate and computational time is compared. It is found that, from an evolutionary point of view, the performance of both GA and PSO is quite adequate. But, GA seems to arrive at its final parameter value in a fewer generations than the PSO. It is also noticed that, the computation time for implemented GA in this work is too high in comparison to PSO.

  8. Microtrauma stimulates rat Achilles tendon healing via an early gene expression pattern similar to mechanical loading

    DEFF Research Database (Denmark)

    Hammerman, Malin; Aspenberg, Per; Eliasson, Pernilla

    2014-01-01

    . Sixteen of the 19 genes were regulated after 3 h, in the same way as after loading. In conclusion, needling increased strength, and there was a striking similarity between the gene expression response to needling and mechanical loading. This suggests that the response to loading in early tendon healing...

  9. The use of Electronic Speckle Pattern Interferometry (ESPI) to determine the displacements in thin adhesive layers under increasing loads (Posterpresentatie)

    NARCIS (Netherlands)

    Botter, H.; Wijen, H.L.M.; Berg, A. van den; Soetens, F.; Straalen, IJ.J. van; Vlot, A.

    2001-01-01

    Recent developments in hardware and software have allowed traditional speckle pattern. interferom.etry using photographic film to be replaced by digital video CCD cameras and sophisticated analysing software. Real-time in-situ displacement measurement of specimens under static or cyclic loads is now

  10. Optimisation by hierarchical search

    Science.gov (United States)

    Zintchenko, Ilia; Hastings, Matthew; Troyer, Matthias

    2015-03-01

    Finding optimal values for a set of variables relative to a cost function gives rise to some of the hardest problems in physics, computer science and applied mathematics. Although often very simple in their formulation, these problems have a complex cost function landscape which prevents currently known algorithms from efficiently finding the global optimum. Countless techniques have been proposed to partially circumvent this problem, but an efficient method is yet to be found. We present a heuristic, general purpose approach to potentially improve the performance of conventional algorithms or special purpose hardware devices by optimising groups of variables in a hierarchical way. We apply this approach to problems in combinatorial optimisation, machine learning and other fields.

  11. Efficient topology optimisation of multiscale and multiphysics problems

    DEFF Research Database (Denmark)

    Alexandersen, Joe

    The aim of this Thesis is to present efficient methods for optimising high-resolution problems of a multiscale and multiphysics nature. The Thesis consists of two parts: one treating topology optimisation of microstructural details and the other treating topology optimisation of conjugate heat...... transfer problems. Part I begins with an introduction to the concept of microstructural details in the context of topology optimisation. Relevant literature is briefly reviewed and problems with existing methodologies are identified. The proposed methodology and its strengths are summarised. Details...... the computational cost of treating structures with fully-resolved microstructural details. The methodology is further applied to examples, where it is shown that it ensures connectivity of the microstructural details and that forced periodicity of the microstructural details can yield an implicit robustness to load...

  12. Buckling optimisation of sandwich cylindrical panels

    Science.gov (United States)

    Abouhamzeh, M.; Sadighi, M.

    2016-06-01

    In this paper, the buckling load optimisation is performed on sandwich cylindrical panels. A finite element program is developed in MATLAB to solve the governing differential equations of the global buckling of the structure. In order to find the optimal solution, the genetic algorithm Toolbox in MATLAB is implemented. Verifications are made for both the buckling finite element code and also the results from the genetic algorithm by comparisons to the results available in literature. Sandwich cylindrical panels are optimised for the buckling strength with isotropic or orthotropic cores with different boundary conditions. Results are presented in terms of stacking sequence of fibers in the face sheets and core to face sheet thickness ratio.

  13. Axial loading verification method for small bones using carrier fringes in speckle pattern interferometry

    Science.gov (United States)

    Dávila, A.; Márquez, S.; Landgrave, E.; Vázquez, Z.; Vera, K.; Caudillo, C.

    2015-06-01

    A computerized system for real-time displacement visualization using carrier fringes in an electronic speckle in-plane sensitive interferometer allows force calibration for micro-displacement analysis of rat bones and verification of axial loading conditions. Once the force has been calibrated and the load is applied along the bone axis, the difference-of-phase method is used to obtain the phase map, which after phase unwrapping, allows the evaluation of the displacements produced by the bone deformation. The proposed method avoids common loading mistakes using first carrier fringes to assure that the loads are within the measuring capabilities of the in-plane interferometer and the Carré phase-stepping method to compensate for linear phase step miscalibration. The experimental results obtained with the calibration of loading forces and axial loading verification show the advantages of the system proposed here over a system which uses a cantilever configuration to make a similar bone deformation analysis.

  14. Dynamic Patterns of Forces and Loading Rate in Runners with Unilateral Plantar Fasciitis: A Cross-Sectional Study.

    Directory of Open Access Journals (Sweden)

    Ana Paula Ribeiro

    Full Text Available The etiology of plantar fasciitis (PF has been related to several risk factors, but the magnitude of the plantar load is the most commonly described factor. Although PF is the third most-common injury in runners, only two studies have investigated this factor in runners, and their results are still inconclusive regarding the injury stage.Analyze and compare the plantar loads and vertical loading rate during running of runners in the acute stage of PF to those in the chronic stage of the injury in relation to healthy runners.Forty-five runners with unilateral PF (30 acute and 15 chronic and 30 healthy control runners were evaluated while running at 12 km/h for 40 meters wearing standardized running shoes and Pedar-X insoles. The contact area and time, maximum force, and force-time integral over the rearfoot, midfoot, and forefoot were recorded and the loading rate (20-80% of the first vertical peak was calculated. Groups were compared by ANOVAs (p<0.05.Maximum force and force-time integral over the rearfoot and the loading rate was higher in runners with PF (acute and chronic compared with controls (p<0.01. Runners with PF in the acute stage showed lower loading rate and maximum force over the rearfoot compared to runners in the chronic stage (p<0.01.Runners with PF showed different dynamic patterns of plantar loads during running over the rearfoot area depending on the injury stage (acute or chronic. In the acute stage of PF, runners presented lower loading rate and forces over the rearfoot, possibly due to dynamic mechanisms related to pain protection of the calcaneal area.

  15. STUDY OF HIGHER MODE EFFECTS AND LATERAL LOAD PATTERNS IN PUSHOVER ANALYSIS OF STEEL FRAMES WITH STEEL SHEAR WALL

    Directory of Open Access Journals (Sweden)

    Mohammad Ghanoonibagha

    2016-03-01

    Full Text Available When an earthquake occurs, the structure will enter into a nonlinear stage; therefore, new approaches based on nonlinear analysis are needed to flourish with the purpose of more realistic investigations on seismic behavior and destruction mechanism of structures. According to the modern philosophy, “Performance-based Earthquake Engineering” is formed in which simple nonlinear static analyses are mostly used in order to determine the structure’s behavior in nonlinear stage. This method assumes that the structure response is only controlled by the main mode and the shape of this mode will remain the same, while it enters the nonlinear stage. Both of these assumptions are approximations, especially in high buildings, which have a long period. It seems that constant load pattern used in these methods cannot consider all of the effects properly. In this paper, an attempt was made to study the accuracy of these methods in comparison to nonlinear dynamic analysis, by considering various load patterns existing in FEMA, also load patterns proportional to higher modes in nonlinear static method, and employing an approximative method of MPA modal analysis, study the accuracy of these methods in comparison to nonlinear dynamic analysis. For this purpose, three steel frames of 4, 8, and 12-stories with steel shear wall have been studied.

  16. A Global Optimisation Toolbox for Massively Parallel Engineering Optimisation

    CERN Document Server

    Biscani, Francesco; Yam, Chit Hong

    2010-01-01

    A software platform for global optimisation, called PaGMO, has been developed within the Advanced Concepts Team (ACT) at the European Space Agency, and was recently released as an open-source project. PaGMO is built to tackle high-dimensional global optimisation problems, and it has been successfully used to find solutions to real-life engineering problems among which the preliminary design of interplanetary spacecraft trajectories - both chemical (including multiple flybys and deep-space maneuvers) and low-thrust (limited, at the moment, to single phase trajectories), the inverse design of nano-structured radiators and the design of non-reactive controllers for planetary rovers. Featuring an arsenal of global and local optimisation algorithms (including genetic algorithms, differential evolution, simulated annealing, particle swarm optimisation, compass search, improved harmony search, and various interfaces to libraries for local optimisation such as SNOPT, IPOPT, GSL and NLopt), PaGMO is at its core a C++ ...

  17. Parents need support to find ways to optimise their own sleep without seeing their preterm infant's sleeping patterns as a problem.

    Science.gov (United States)

    Blomqvist, Ylva Thernström; Nyqvist, Kerstin Hedberg; Rubertsson, Christine; Funkquist, Eva-Lotta

    2017-02-01

    This study described how parents perceived their own sleep, and their infants', during neonatal intensive care unit (NICU) admission and after discharge. It also explored the infants' sleeping location at home. The study was conducted in the NICUs of two Swedish university hospitals. The parents of 86 infants - 86 mothers and 84 fathers - answered questionnaires during their infants' hospital stay, at discharge and at the infants' corrected ages of two, six and 12 months. The parents' own sleep was explored with the Insomnia Severity Index. Mothers reported more severe insomnia than fathers during their infants' hospitalisation, and these higher insomnia severity scores were associated with more severe infant sleep problems at discharge (p = 0.027) and at two months (p = 0.006) and 12 months (p = 0.002) of corrected age. During the study period, 4%-10% of the parents reported severe or very severe infant sleeping problems. The bed-sharing rate was 75% after discharge and about 60% at the corrected age of 12 months. Maternal insomnia during an infant's hospital stay was associated with later perceptions of sleep problems in their children. Parents need support to find solutions for optimal sleep without seeing their child's sleeping patterns as a problem. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  18. Different knee joint loading patterns in ACL deficient copers and non-copers during walking

    DEFF Research Database (Denmark)

    Alkjaer, Tine; Henriksen, Marius; Simonsen, Erik B

    2011-01-01

    Rupture of the anterior cruciate ligament (ACL) causes changes in the walking pattern. ACL deficient subjects classified as copers and non-copers have been observed to adopt different post-injury walking patterns. How these different patterns affect the knee compression and shear forces is unreso......Rupture of the anterior cruciate ligament (ACL) causes changes in the walking pattern. ACL deficient subjects classified as copers and non-copers have been observed to adopt different post-injury walking patterns. How these different patterns affect the knee compression and shear forces...... is unresolved. Thus, the aim of the present study was to investigate how different walking patterns observed between copers, non-copers, and controls affect the knee compression and shear forces during walking....

  19. Simple Combinatorial Optimisation Cost Games

    NARCIS (Netherlands)

    van Velzen, S.

    2005-01-01

    In this paper we introduce the class of simple combinatorial optimisation cost games, which are games associated to {0, 1}-matrices.A coalitional value of a combinatorial optimisation game is determined by solving an integer program associated with this matrix and the characteristic vector of the

  20. Distance-decay patterns of nutrient loading at watershed scale: Regression modeling with a special spatial aggregation strategy

    Science.gov (United States)

    Zhang, Tao

    2011-05-01

    SummaryThe effect of distance-decay on nutrient flux usually plays an important role in nutrient retention from non-point sources to surface waters. However, the distance-decay effect has been inappropriately neglected in many studies that adopted regression modeling method to quantify the relationship between watershed landscape and in-stream nutrient loading level. The goal of this study was to develop non-linear regression models that better quantify the role of distance on non-point source nutrient loads in rivers by using simulation results of a spatially-explicit model applied to the watersheds in the Upper Chattahoochee River Basin, Georgia. Because a detailed spatially-explicit modeling approach typically simulates the nutrient flux across the entire watershed, it provides opportunities to examine the nutrient decay patterns at watershed scale. The simulation results confirmed that regarding the effect of flow distance on nutrient loading, the exponential decay setting in the spatially-explicit model performs well. Other heterogeneous factors including slope and soil conditions do affect the decay results but not strongly enough to change the general exponential patterns. The nutrient contribution from areas that were greater than 300 meters to the river network was negligible. It was also found that the decay rate for urban lands is lower than that for other land-covers. Based on these findings, a spatial aggregation strategy in the lateral dimension of the river network was adopted and eight non-linear regression models which explicitly addressed the effects of distance-decay were designed to estimate the nutrient annual average loads. The model validation results showed that three of them can well estimate the nutrient loads. This study shows the usage of stream-lateral-dimension aggregation strategy in addressing nutrient distance-decay patterns and developing simple regression models of nutrient loading. This study also illustrates the advantages of

  1. Non-spherical voids and lattice reorientation patterning in a shock-loaded Al single crystal

    DEFF Research Database (Denmark)

    Hong, Chuanshi; Fæster, Søren; Hansen, Niels

    2017-01-01

    An Al single crystal shock loaded in the direction and captured at incipient spallation was examined by combining X-ray tomography, electron backscatter diffraction on a scanning electron microscope, and transmission electron microscopy (TEM). Octahedral voids with {1 1 1} faces were...

  2. Optimising a shaft's geometry by applying genetic algorithms

    Directory of Open Access Journals (Sweden)

    María Alejandra Guzmán

    2010-04-01

    Full Text Available Many engnieering design tasks involve optimising several conflicting goals; these types of problem are known as Multiobjective Optimisation Problems (MOPs. Evolutionary techniques have proved to be an effective tool for finding solutions to these MOPs during the last decade, Variations on the basic generic algorithm have been particulary proposed by different researchers for finding rapid optimal solutions to MOPs. The NSGA (Non-dominated Sorting Generic Algorithm has been implemented in this paper for finding an optimal design for a shaft subjected to cyclic loads, the conflycting goals being minimum weight and minimum lateral deflection.

  3. Relationships between the Definition of the Hyperplane Width to the Fidelity of Principal Component Loading Patterns.

    Science.gov (United States)

    Richman, Michael B.; Gong, Xiaofeng

    1999-06-01

    When applying eigenanalysis, one decision analysts make is the determination of what magnitude an eigenvector coefficient (e.g., principal component (PC) loading) must achieve to be considered as physically important. Such coefficients can be displayed on maps or in a time series or tables to gain a fuller understanding of a large array of multivariate data. Previously, such a decision on what value of loading designates a useful signal (hereafter called the loading `cutoff') for each eigenvector has been purely subjective. The importance of selecting such a cutoff is apparent since those loading elements in the range of zero to the cutoff are ignored in the interpretation and naming of PCs since only the absolute values of loadings greater than the cutoff are physically analyzed. This research sets out to objectify the problem of best identifying the cutoff by application of matching between known correlation/covariance structures and their corresponding eigenpatterns, as this cutoff point (known as the hyperplane width) is varied.A Monte Carlo framework is used to resample at five sample sizes. Fourteen different hyperplane cutoff widths are tested, bootstrap resampled 50 times to obtain stable results. The key findings are that the location of an optimal hyperplane cutoff width (one which maximized the information content match between the eigenvector and the parent dispersion matrix from which it was derived) is a well-behaved unimodal function. On an individual eigenvector, this enables the unique determination of a hyperplane cutoff value to be used to separate those loadings that best reflect the relationships from those that do not. The effects of sample size on the matching accuracy are dramatic as the values for all solutions (i.e., unrotated, rotated) rose steadily from 25 through 250 observations and then weakly thereafter. The specific matching coefficients are useful to assess the penalties incurred when one analyzes eigenvector coefficients of a

  4. Topology optimised wavelength dependent splitters

    DEFF Research Database (Denmark)

    Hede, K. K.; Burgos Leon, J.; Frandsen, Lars Hagedorn

    A photonic crystal wavelength dependent splitter has been constructed by utilising topology optimisation1. The splitter has been fabricated in a silicon-on-insulator material (Fig. 1). The topology optimised wavelength dependent splitter demonstrates promising 3D FDTD simulation results....... This complex photonic crystal structure is very sensitive against small fabrication variations from the expected topology optimised design. A wavelength dependent splitter is an important basic building block for high-performance nanophotonic circuits. 1J. S. Jensen and O. Sigmund, App. Phys. Lett. 84, 2022...

  5. Engineering Optimisation by Cuckoo Search

    CERN Document Server

    Yang, Xin-She

    2010-01-01

    A new metaheuristic optimisation algorithm, called Cuckoo Search (CS), was developed recently by Yang and Deb (2009). This paper presents a more extensive comparison study using some standard test functions and newly designed stochastic test functions. We then apply the CS algorithm to solve engineering design optimisation problems, including the design of springs and welded beam structures. The optimal solutions obtained by CS are far better than the best solutions obtained by an efficient particle swarm optimiser. We will discuss the unique search features used in CS and the implications for further research.

  6. Topology optimised wavelength dependent splitters

    DEFF Research Database (Denmark)

    Hede, K. K.; Burgos Leon, J.; Frandsen, Lars Hagedorn;

    A photonic crystal wavelength dependent splitter has been constructed by utilising topology optimisation1. The splitter has been fabricated in a silicon-on-insulator material (Fig. 1). The topology optimised wavelength dependent splitter demonstrates promising 3D FDTD simulation results....... This complex photonic crystal structure is very sensitive against small fabrication variations from the expected topology optimised design. A wavelength dependent splitter is an important basic building block for high-performance nanophotonic circuits. 1J. S. Jensen and O. Sigmund, App. Phys. Lett. 84, 2022...

  7. Age-related worm load and worm fecundity patterns in human populations, as indicated by schistosome circulating antigens

    Directory of Open Access Journals (Sweden)

    Polman Katja

    1998-01-01

    Full Text Available Recently, our group determined the relationship between serum CAA levels and fecal egg counts in two foci with very intense Schistosoma mansoni transmission: Maniema (Zaire, an area endemic for S. mansoni since several decades, and Ndombo (Senegal, where transmission has only been established since a few years. The objective was to study and compare age-related worm load and worm fecundity patterns in these two different endemic settings. Here, we will summarize the most important findings and conclusions of this study.

  8. Optimisation of the Laser Cutting Process

    DEFF Research Database (Denmark)

    Dragsted, Birgitte; Olsen, Flemmming Ove

    1996-01-01

    The problem in optimising the laser cutting process is outlined. Basic optimisation criteria and principles for adapting an optimisation method, the simplex method, are presented. The results of implementing a response function in the optimisation are discussed with respect to the quality as well...

  9. Isogeometric Analysis and Shape Optimisation

    DEFF Research Database (Denmark)

    Gravesen, Jens; Evgrafov, Anton; Gersborg, Allan Roulund

    obtained and also some of the problems we have encountered. One of these problems is that the geometry of the shape is given by the boundary alone. And, it is the parametrisation of the boundary which is changed by the optimisation procedure. But isogeometric analysis requires a parametrisation......One of the attractive features of isogeometric analysis is the exact representation of the geometry. The geometry is furthermore given by a relative low number of control points and this makes isogeometric analysis an ideal basis for shape optimisation. I will describe some of the results we have...... of the whole domain. So in every optimisation cycle we need to extend a parametrisation of the boundary of a domain to the whole domain. It has to be fast in order not to slow the optimisation down but it also has to be robust and give a parametrisation of high quality. These are conflicting requirements so we...

  10. Turbulence optimisation in stellarator experiments

    Energy Technology Data Exchange (ETDEWEB)

    Proll, Josefine H.E. [Max-Planck/Princeton Center for Plasma Physics (Germany); Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstr. 1, 17491 Greifswald (Germany); Faber, Benjamin J. [HSX Plasma Laboratory, University of Wisconsin-Madison, Madison, WI 53706 (United States); Helander, Per; Xanthopoulos, Pavlos [Max-Planck/Princeton Center for Plasma Physics (Germany); Lazerson, Samuel A.; Mynick, Harry E. [Plasma Physics Laboratory, Princeton University, P.O. Box 451 Princeton, New Jersey 08543-0451 (United States)

    2015-05-01

    Stellarators, the twisted siblings of the axisymmetric fusion experiments called tokamaks, have historically suffered from confining the heat of the plasma insufficiently compared with tokamaks and were therefore considered to be less promising candidates for a fusion reactor. This has changed, however, with the advent of stellarators in which the laminar transport is reduced to levels below that of tokamaks by shaping the magnetic field accordingly. As in tokamaks, the turbulent transport remains as the now dominant transport channel. Recent analytical theory suggests that the large configuration space of stellarators allows for an additional optimisation of the magnetic field to also reduce the turbulent transport. In this talk, the idea behind the turbulence optimisation is explained. We also present how an optimised equilibrium is obtained and how it might differ from the equilibrium field of an already existing device, and we compare experimental turbulence measurements in different configurations of the HSX stellarator in order to test the optimisation procedure.

  11. Investigating Theoretical PV Energy Generation Patterns with Their Relation to the Power Load Curve in Poland

    Directory of Open Access Journals (Sweden)

    Jakub Jurasz

    2016-01-01

    Full Text Available Polish energy sector is (almost from its origin dominated by fossil fuel feed power. This situation results from an abundance of relatively cheap coal (hard and lignite. Brown coal due to its nature is the cheapest energy source in Poland. However, hard coal which fuels 60% of polish power plants is picking up on prices and is susceptible to the coal imported from neighboring countries. Forced by the European Union (EU regulations, Poland is struggling at achieving its goal of reaching 15% of energy consumption from renewable energy sources (RES by 2020. Over the year 2015, RES covered 11.3% of gross energy consumption but this generation was dominated by solid biomass (over 80%. The aim of this paper was to answer the following research questions: What is the relation of irradiation values to the power load on a yearly and daily basis? and how should photovoltaics (PV be integrated in the polish power system? Conducted analysis allowed us to state that there exists a negative correlation between power demand and irradiation values on a yearly basis, but this is likely to change in the future. Secondly, on average, daily values of irradiation tend to follow power load curve over the first hours of the day.

  12. Changes in the drug release pattern of fresh and set simvastatin-loaded brushite cement.

    Science.gov (United States)

    Mestres, Gemma; Kugiejko, Karol; Pastorino, David; Unosson, Johanna; Öhman, Caroline; Karlsson Ott, Marjam; Ginebra, Maria-Pau; Persson, Cecilia

    2016-01-01

    Calcium phosphate cements are synthetic bone graft substitutes able to set at physiological conditions. They can be applied by minimally invasive surgery and can also be used as drug delivery systems. Consequently, the drug release pattern from the cement paste (fresh cement) is of high clinical interest. However, previous studies have commonly evaluated the drug release using pre-set cements only. Therefore, the aim of this work was to determine if the time elapsed from cement preparation until immersion in the solution (3 min for fresh cements, and 1h and 15 h for pre-set cements) had an influence on its physical properties, and correlating these to the drug release profile. Simvastatin was selected as a model drug, while brushite cement was used as drug carrier. This study quantified how the setting of a material reduces the accessibility of the release media to the material, thus preventing drug release. A shift in the drug release pattern was observed, from a burst-release for fresh cements to a sustained release for pre-set cements.

  13. Exercise Alters Gait Pattern but Not Knee Load in Patients with Knee Osteoarthritis

    Science.gov (United States)

    Lin, Yi-Jia; Chang, Chao-Chin; Chou, You-Cai

    2016-01-01

    Six female patients with bilateral medial knee OA and 6 healthy controls were recruited. Patients with knee OA received a 6-week physiotherapist-supervised and home-based exercise program. Outcome measures, including the Western Ontario and McMaster Universities Arthritis Index and Short Form-36 Health Survey as well as objective biomechanical indices were obtained at baseline and follow-up. After treatment, no significant difference was observed in the knee abductor moment (KAM), lever arm, and ground reaction force. We, however, observed significantly improved pain and physical function as well as altered gait patterns, including a higher hip flexor moment and hip extension angle with a faster walking speed. Although KAM was unchanged, patients with bilateral knee OA showed an improved walking speed and altered the gait pattern after 6 weeks of supervised exercise. This finding suggests that the exercise intervention improves proximal joint mechanics during walking and can be considered for patients with bilateral knee OA. Non-weight-bearing strengthening without external resistance combined with stretching exercise may be an option to improve pain and function in individuals with OA who cannot perform high resistance exercises owing to pain or other reasons. PMID:27725941

  14. Exercise Alters Gait Pattern but Not Knee Load in Patients with Knee Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Ssu-Yu Chang

    2016-01-01

    Full Text Available Six female patients with bilateral medial knee OA and 6 healthy controls were recruited. Patients with knee OA received a 6-week physiotherapist-supervised and home-based exercise program. Outcome measures, including the Western Ontario and McMaster Universities Arthritis Index and Short Form-36 Health Survey as well as objective biomechanical indices were obtained at baseline and follow-up. After treatment, no significant difference was observed in the knee abductor moment (KAM, lever arm, and ground reaction force. We, however, observed significantly improved pain and physical function as well as altered gait patterns, including a higher hip flexor moment and hip extension angle with a faster walking speed. Although KAM was unchanged, patients with bilateral knee OA showed an improved walking speed and altered the gait pattern after 6 weeks of supervised exercise. This finding suggests that the exercise intervention improves proximal joint mechanics during walking and can be considered for patients with bilateral knee OA. Non-weight-bearing strengthening without external resistance combined with stretching exercise may be an option to improve pain and function in individuals with OA who cannot perform high resistance exercises owing to pain or other reasons.

  15. Is Lumbo-Sacral Angle Related to Plantar Loading Patterns in Patients with Ankylosing Spondylitis?

    Directory of Open Access Journals (Sweden)

    Elif Aydın

    2016-08-01

    Full Text Available Objective: Loss of lumbar lordosis is a clinical feature of ankylosing spondylitis (AS. Pedobarographic analysis assesses the interaction between the foot and the supporting surface. Postural abnormalities can reflect as pressure distribution deviations on pedobarography. The objective of the present study was to assess whether loss of lumbar lordosis detected with lumbo-sacral angle measurement is related to postural control assessed by plantar loading distribution in patients with AS. Materials and Methods: Thirty-two patients (two female, 30 male, mean age: 43.06±7.8 years with the diagnosis of AS, who already had a lateral lumbo-sacral X-ray performed within the past one year, were included in the study. Static and dynamic pedobarographic analyses of the patients were performed. The radiographic measurement of lumbo-sacral angle was done from lateral lumbo-sacral X-rays of the patients. Results: The static pedobarographic measurement revealed that lumbo-sacral angle was significantly correlated with forefoot plantar pressure (p=0.042; r=0.361. In the dynamic assessment, the maximum pressures were lower under the first metatarsal area in patients with lower lumbo-sacral angle (p=0.352; r=0.048. Conclusion: These findings suggest that foot joints may contribute to the compensation mechanism against the postural changes in patients with AS, statically and dynamically.

  16. AN EXPLORATORY ANALYSIS ON HALF-HOURLY ELECTRICITY LOAD PATTERNS LEADING TO HIGHER PERFORMANCES IN NEU

    Directory of Open Access Journals (Sweden)

    K.A.D. Deshani

    2014-05-01

    Full Text Available Accurate prediction of electricity demand can bring extensive benefits to any country as the forecasted values help the relevant authorities to take decisions regarding electricity generation, transmission and distribution appropriately. The literature reveals that, when compared to conventional time series techniques, the improved artificial intelligent approaches provide better prediction accuracies. However, the accuracy of predictions using intelligent approaches like neural networks are strongly influenced by the correct selection of inputs and the number of neuro-forecasters used for prediction. Deshani, Hansen, Attygalle, & Karunarathne (2014 suggested that a cluster analysis could be performed to group similar day types, which contribute towards selecting a better set of neuro-forecasters in neural networks. The cluster analysis was based on the daily total electricity demands as their target was to predict the daily total demands using neural networks. However, predicting half-hourly demand seems more appropriate due to the considerable changes of electricity demand observed during a particular day. As such clusters are identified considering half-hourly data within the daily load distribution curves. Thus, this paper is an improvement to Deshani et. al. (2014, which illustrates how the half hourly demand distribution within a day, is incorporated when selecting the inputs for the neuro-forecasters.

  17. Optimising Antibiotic Usage to Treat Bacterial Infections

    Science.gov (United States)

    Paterson, Iona K.; Hoyle, Andy; Ochoa, Gabriela; Baker-Austin, Craig; Taylor, Nick G. H.

    2016-11-01

    The increase in antibiotic resistant bacteria poses a threat to the continued use of antibiotics to treat bacterial infections. The overuse and misuse of antibiotics has been identified as a significant driver in the emergence of resistance. Finding optimal treatment regimens is therefore critical in ensuring the prolonged effectiveness of these antibiotics. This study uses mathematical modelling to analyse the effect traditional treatment regimens have on the dynamics of a bacterial infection. Using a novel approach, a genetic algorithm, the study then identifies improved treatment regimens. Using a single antibiotic the genetic algorithm identifies regimens which minimise the amount of antibiotic used while maximising bacterial eradication. Although exact treatments are highly dependent on parameter values and initial bacterial load, a significant common trend is identified throughout the results. A treatment regimen consisting of a high initial dose followed by an extended tapering of doses is found to optimise the use of antibiotics. This consistently improves the success of eradicating infections, uses less antibiotic than traditional regimens and reduces the time to eradication. The use of genetic algorithms to optimise treatment regimens enables an extensive search of possible regimens, with previous regimens directing the search into regions of better performance.

  18. Levels and patterns of HIV RNA viral load in untreated pregnant women

    DEFF Research Database (Denmark)

    NN, NN; Patel, Deven; Thorne, Claire;

    2008-01-01

    OBJECTIVE: To assess pregnancy levels and patterns of HIV RNA in the absence of antiretroviral therapy, while appropriately adjusting for potential confounders, including maternal immune status and race. METHODS: Data on > or = 1 antenatal HIV RNA measurements were available for 333 untreated HIV......-infected pregnant women enrolled in the European Collaborative Study. CD4 counts and HIV RNA measurements were routinely collected from 1992 and 1998, respectively. Linear mixed effects models based on 246 women for whom complete data were available examined changes in HIV RNA levels over pregnancy, with a nested...... random effects term accounting for measurement variability within women and period of sample collection. RESULTS: The change in HIV RNA over pregnancy varied significantly by race (p=0.005): from the second trimester until delivery, HIV RNA decreased significantly by an estimated 0.019 log(10) copies...

  19. Spatial and temporal patterns of turbidity, sediment concentration and load across nested scales in an urban watershed

    Science.gov (United States)

    Kemper, J. T.; Welty, C.; Miller, A. J.

    2016-12-01

    In a highly regulated area such as the Chesapeake Bay watershed, suspended sediment is a matter of primary concern. However, there are few continuous sediment-concentration records available to quantify urban sediment loads. Near real-time turbidity and discharge data have been collected continuously for more than three years at six stream gages representing three nested watershed scales (1-2 sq km, 5-6 sq km, 14 sq km) in the highly impervious Dead Run watershed, located in Baltimore County, MD. Suspended sediment point samples have been collected for multiple storm events at five of the six sites, to establish provisional relationships between turbidity and suspended sediment concentrations. Using these calculated relationships and USGS discharge data, we can quantify sediment loads at each station. Turbidity-discharge relationships vary both spatially and temporally, highlighting the extreme heterogeneity of an urban watershed. Spatially, relationships change from headwaters to mouth, potentially suggesting a variation in sediment sources. Temporally, relationships change both seasonally and annually. The lowest turbidity values are consistently seen in the fall, while values in winter, spring, and summer display a high inter-annual variability. Sediment loads and yields calculated for four representative storms are compared across nested watershed scales to assess evidence for sources or sinks at different locations within the drainage network. Yields at the mouth of the watershed (DRKR) for large storms were higher than an area-weighted average of the two contributing sites (DR3, DR4), potentially suggesting additional source areas of sediment within the watershed. This highlights the ability of near real-time data to assist in developing more effective approaches in mitigating sediment transport by helping to identifying consistent trends, locations of hot spots, and patterns of sediment arrival.

  20. TEM turbulence optimisation in stellarators

    CERN Document Server

    Proll, J H E; Xanthopoulos, P; Lazerson, S A; Faber, B J

    2015-01-01

    With the advent of neoclassically optimised stellarators, optimising stellarators for turbulent transport is an important next step. The reduction of ion-temperature-gradient-driven turbulence has been achieved via shaping of the magnetic field, and the reduction of trapped-electron mode (TEM) turbulence is adressed in the present paper. Recent analytical and numerical findings suggest TEMs are stabilised when a large fraction of trapped particles experiences favourable bounce-averaged curvature. This is the case for example in Wendelstein 7-X [C.D. Beidler $\\textit{et al}$ Fusion Technology $\\bf{17}$, 148 (1990)] and other Helias-type stellarators. Using this knowledge, a proxy function was designed to estimate the TEM dynamics, allowing optimal configurations for TEM stability to be determined with the STELLOPT [D.A. Spong $\\textit{et al}$ Nucl. Fusion $\\bf{41}$, 711 (2001)] code without extensive turbulence simulations. A first proof-of-principle optimised equilibrium stemming from the TEM-dominated stella...

  1. Water consumption patterns in rural Bangladesh: are we underestimating total arsenic load?

    Science.gov (United States)

    Milton, Abul Hasnat; Rahman, Habibur; Smith, Wayne; Shrestha, Rupendra; Dear, Keith

    2006-12-01

    Risk related to the ingestion of any water contaminants depends on many factors, including the daily per capita amount of consumed water relative to body weight. This study explored the water consumption pattern of a rural arsenic-affected population in Bangladesh. The study findings are likely to contribute to the risk estimation attributable to ingestion of arsenic and other drinking water contaminants. A total of 640 individuals participated in this cross-sectional study carried out in an arsenic-affected rural population in Bangladesh. In this study daily per capita water consumption for drinking purposes was found to be 73.04 ml/kg/d (range = 71.24-74.84 ml/kg/d), which is higher than for both the US and Taiwan populations. This difference in per capita drinking water consumption might contribute to much higher lifetime cancer mortality and other morbidity risks from arsenic among the Bangladesh population compared to either the US or Taiwan populations. Arsenic is also ingested through cooking water which, if considered, might increase the risk further. The findings of this study highlight the urgent need for a holistic water supply programme for Bangladesh, with special emphasis on the arsenic-affected population.

  2. Evaluation of Effect of Fuel Assembly Loading Patterns on Thermal and Shielding Performance of a Spent Fuel Storage/Transportation Cask

    Energy Technology Data Exchange (ETDEWEB)

    Cuta, Judith M.; Jenquin, Urban P.; McKinnon, Mikal A.

    2001-11-20

    The licensing of spent fuel storage casks is generally based on conservative analyses that assume a storage system being uniformly loaded with design basis fuel. The design basis fuel typically assumes a maximum assembly enrichment, maximum burn up, and minimum cooling time. These conditions set the maximum decay heat loads and radioactive source terms for the design. Recognizing that reactor spent fuel pools hold spent fuel with an array of initial enrichments, burners, and cooling times, this study was performed to evaluate the effect of load pattern on peak cladding temperature and cask surface dose rate. Based on the analysis, the authors concluded that load patterns could be used to reduce peak cladding temperatures in a cask without adversely impacting the surface dose rates.

  3. Comparable cerebral oxygenation patterns in younger and older adults during dual-task walking with increasing load

    Directory of Open Access Journals (Sweden)

    Sarah A. Fraser

    2016-10-01

    Full Text Available The neuroimaging literature on dual-task gait clearly demonstrates increased prefrontal cortex (PFC involvement when performing a cognitive task while walking. However, findings from direct comparisons of the cerebral oxygenation patterns of younger (YA and older (OA adults during dual-task walking are mixed and it is unclear how YA and OA respond to increasing cognitive load (difficulty while walking. This functional near infra-red (fNIRS study examined cerebral oxygenation of YA and OA during self-paced dual-task treadmill walking at two different levels of cognitive load (auditory n-back. Changes in accuracy (% as well as oxygenated (HbO and deoxygenated (HbR hemoglobin were examined. For the HbO and HbR measures, eight regions of interest (ROIs were assessed: the anterior and posterior dorsolateral and ventrolateral PFC (aDLPFC, pDLPFC, aVLPFC, pVLPFC in each hemisphere. Nineteen YA (M = 21.83 yrs and 14 OA (M = 66.85 yrs walked at a self-selected pace while performing auditory 1-back and 2-back tasks. Walking alone (single motor: SM and performing the cognitive tasks alone (single cognitive: SC were compared to dual-task walking (DT = SM + SC. In the behavioural data, participants were more accurate in the lowest level of load (1-back compared to the highest (2-back; p ˂ .001. YA were more accurate than OA overall (p = .009, and particularly in the 2-back task (p = .048. In the fNIRS data, both younger and older adults had task effects (SM < DT in specific ROIs for ∆HbO (3 YA, 1 OA and ∆HbR (7 YA, 8 OA. After controlling for walk speed differences, direct comparisons between YA and OA did not reveal significant age differences, but did reveal a difficulty effect in HbO in the left aDLPFC (p = .028 and significant task effects (SM < DT in HbR for 6 of the 8 ROIs. Findings suggest that YA and OA respond similarly to manipulations of cognitive load when walking on a treadmill at a self-selected pace.

  4. The effect of fibre layering pattern in resisting bending loads of natural fibre-based hybrid composite materials

    Directory of Open Access Journals (Sweden)

    Jusoh Muhamad Shahirul Mat

    2016-01-01

    Full Text Available The effect of fibre layering pattern and hybridization on the flexural properties of composite hybrid laminates between natural fibres of basalt, jute and flax with synthetic fibre of E-glass reinforced epoxy have been investigated experimentally. Results showed that the effect fibre layering pattern was highly significant on the flexural strength and modulus, which were strongly dependent on the hybrid configuration between sandwich-like (SL and intercalation (IC sequence of fibre layers. In addition, specific modulus based on the variation densities of the hybrid laminates was used to discover the best combination either basalt, jute or flax with E-glass exhibits superior properties concerning on the strength to weight-ratio. Generally, SL sequence of glass/basalt exhibited superior strength and stiffness compared with glass/jute and glass/flax in resisting bending loads. In terms of hybridization effect, glass/jute was found to be the best combination with E-glass compared to the rest of natural fibres investigated in the present study. Hence, the proper stacking sequences and material selection are among predominant factors that influence on mechanical properties and very crucial in designing composite hybrid system to meet the desired requirements.

  5. Sustainable management of a coupled groundwater-agriculture hydrosystem using multi-criteria simulation based optimisation.

    Science.gov (United States)

    Grundmann, Jens; Schütze, Niels; Lennartz, Franz

    2013-01-01

    In this paper we present a new simulation-based integrated water management tool for sustainable water resources management in arid coastal environments. This tool delivers optimised groundwater withdrawal scenarios considering saltwater intrusion as a result of agricultural and municipal water abstraction. It also yields a substantially improved water use efficiency of irrigated agriculture. To allow for a robust and fast operation we unified process modelling with artificial intelligence tools and evolutionary optimisation techniques. The aquifer behaviour is represented using an artificial neural network (ANN) which emulates a numerical density-dependent groundwater flow model. The impact of agriculture is represented by stochastic crop water production functions (SCWPF). Simulation-based optimisation techniques together with the SCWPF and ANN deliver optimal groundwater abstraction and cropping patterns. To address contradicting objectives, e.g. profit-oriented agriculture vs. sustainable abstraction scenarios, we performed multi-objective optimisations using a multi-criteria optimisation algorithm.

  6. Cogeneration technologies, optimisation and implementation

    CERN Document Server

    Frangopoulos, Christos A

    2017-01-01

    Cogeneration refers to the use of a power station to deliver two or more useful forms of energy, for example, to generate electricity and heat at the same time. This book provides an integrated treatment of cogeneration, including a tour of the available technologies and their features, and how these systems can be analysed and optimised.

  7. Optimisation of solar synoptic observations

    Science.gov (United States)

    Klvaña, Miroslav; Sobotka, Michal; Švanda, Michal

    2012-09-01

    The development of instrumental and computer technologies is connected with steadily increasing needs for archiving of large data volumes. The current trend to meet this requirement includes the data compression and growth of storage capacities. This approach, however, has technical and practical limits. A further reduction of the archived data volume can be achieved by means of an optimisation of the archiving that consists in data selection without losing the useful information. We describe a method of optimised archiving of solar images, based on the selection of images that contain a new information. The new information content is evaluated by means of the analysis of changes detected in the images. We present characteristics of different kinds of image changes and divide them into fictitious changes with a disturbing effect and real changes that provide a new information. In block diagrams describing the selection and archiving, we demonstrate the influence of clouds, the recording of images during an active event on the Sun, including a period before the event onset, and the archiving of long-term history of solar activity. The described optimisation technique is not suitable for helioseismology, because it does not conserve the uniform time step in the archived sequence and removes the information about solar oscillations. In case of long-term synoptic observations, the optimised archiving can save a large amount of storage capacities. The actual capacity saving will depend on the setting of the change-detection sensitivity and on the capability to exclude the fictitious changes.

  8. For Time-Continuous Optimisation

    DEFF Research Database (Denmark)

    Heinrich, Mary Katherine; Ayres, Phil

    2016-01-01

    Strategies for optimisation in design normatively assume an artefact end-point, disallowing continuous architecture that engages living systems, dynamic behaviour, and complex systems. In our Flora Robotica investigations of symbiotic plant-robot bio-hybrids, we re- quire computational tools...

  9. For Time-Continuous Optimisation

    DEFF Research Database (Denmark)

    Heinrich, Mary Katherine; Ayres, Phil

    2016-01-01

    Strategies for optimisation in design normatively assume an artefact end-point, disallowing continuous architecture that engages living systems, dynamic behaviour, and complex systems. In our Flora Robotica investigations of symbiotic plant-robot bio-hybrids, we re- quire computational tools...

  10. A Bayesian Approach for Sensor Optimisation in Impact Identification

    Directory of Open Access Journals (Sweden)

    Vincenzo Mallardo

    2016-11-01

    Full Text Available This paper presents a Bayesian approach for optimizing the position of sensors aimed at impact identification in composite structures under operational conditions. The uncertainty in the sensor data has been represented by statistical distributions of the recorded signals. An optimisation strategy based on the genetic algorithm is proposed to find the best sensor combination aimed at locating impacts on composite structures. A Bayesian-based objective function is adopted in the optimisation procedure as an indicator of the performance of meta-models developed for different sensor combinations to locate various impact events. To represent a real structure under operational load and to increase the reliability of the Structural Health Monitoring (SHM system, the probability of malfunctioning sensors is included in the optimisation. The reliability and the robustness of the procedure is tested with experimental and numerical examples. Finally, the proposed optimisation algorithm is applied to a composite stiffened panel for both the uniform and non-uniform probability of impact occurrence.

  11. Pattern of aerosol mass loading and chemical composition over the atmospheric environment of an urban coastal station

    Science.gov (United States)

    Bindu, G.; Nair, Prabha R.; Aryasree, S.; Hegde, Prashant; Jacob, Salu

    2016-02-01

    Aerosol sampling was carried out at four locations in and around Cochin (9°58‧ N, 76°17‧ E), an urban area, located on the southwest coast of India. The gravimetric estimates of aerosol mass loading showed wide range from 78 μg m-3 to >450 μg m-3, occasionally reaching values >500 μg m-3, associated with regional source characteristics. Most of the values were above the air quality standard. Both boundary layer and synoptic scale airflow pattern play role in the temporal features in aerosol mass loading and chemical composition. Chemical analysis of the aerosol samples were done for anionic species viz; F-, Cl-, Br-, NO2-,   NO3-,   PO43-,   SO42- and metallic/cationic species viz; Na, Ca, K, Mg, NH4+, Fe, Al, Cu, Mg, Pb, etc using Ion Chromatography, Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma- Atomic Emission Spectroscopy (ICP-AES). At all the locations, extremely high mass concentration of SO42- was observed with the mean value of 13±6.4 μg m-3 indicating the strong anthropogenic influence. Statistical analysis of the chemical composition data was carried out and the principal factors presented. Seasonal variation of these chemical species along with their percentage contributions and regional variations were also examined. Increase in level of Na in aerosol samples indicated the influence of monsoonal activity. Most of the species showed mass concentrations well above those measured over another coastal site Thiruvananthapuram (8°29‧ N, 76°57‧ E) situated ~220 km south of Cochin revealing the highly localized aerosol features.

  12. Exercises for the torso performed in a standing posture: spine and hip motion and motor patterns and spine load.

    Science.gov (United States)

    McGill, Stuart M; Karpowicz, Amy; Fenwick, Chad M J; Brown, Stephen H M

    2009-03-01

    The purpose of this study was to document the muscle activity, spine motion, spine load, and stiffness during several movement-based or "functional" exercises and to assess the effect of technique change. Eight subjects, all healthy men from a university population, were instrumented to obtain surface electromyography of selected trunk and hip muscles, together with video analysis and electromagnetic lumbar spine position sensor to track spine posture. Exercises included a walkout in the sagittal plane that compared an upright form against a wall with those performed on the floor, overhead cable pushes, lateral cable walkouts, the good morning exercise, and the bowler's squat. Generally, muscle activation levels were quite modest even though the tasks were quite strenuous in many cases. Even though similar joint moments were required in different exercises, the pattern of activity between muscles was different. Abdominal bracing increased spine stiffness at the expense of more spine load. Thus, muscle activity seems to be constrained in "functional" exercises. There are several possible reasons for this. Single muscles cannot be activated to 100% of the maximum voluntary contraction in functional exercises because this would upset the balance of moments about the 3 orthopedic axes of the spine, or it would upset the balance of stiffening muscles around the spine required to ensure stability of the spinal column. The one exception was the floor walkout, which resulted in full activation of the rectus abdominis; however, this was a sagittal plane task without the joint moment constraints of multiplanar exercise. Therefore, maximal muscle activity is observed during single-plane tasks, but muscle activation levels were constrained during functional tasks. Thus, strength training muscles may not help in "functional multiplanar" tasks. These data can be used to assist decisions regarding the selection of exercises, specifically choices regarding the starting challenge

  13. Simulation and optimisation of turbulence in stellarators

    Energy Technology Data Exchange (ETDEWEB)

    Xanthopoulos, Pavlos; Helander, Per; Turkin, Yuriy; Plunk, Gabriel G.; Bird, Thomas; Proll, Josefine H.E. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); Mynick, Harry [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Jenko, Frank; Goerler, Tobias; Told, Daniel [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2014-07-01

    In tokamaks and stellarators - two leading types of devices used in fusion research - magnetic field lines trace out toroidal surfaces on which the plasma density and temperature are constant, but turbulent fluctuations carry energy across these surfaces to the wall, thus degrading the plasma confinement. Using petaflop-scale simulations, we calculate for the first time the pattern of turbulent structures forming on stellarator magnetic surfaces, and find striking differences relative to tokamaks. The observed sensitivity of the turbulence to the magnetic geometry suggests that there is room for further confinement improvement, in addition to measures already taken to minimise the laminar transport. With an eye towards fully optimised stellarators, we present a proof-of-principle configuration with substantially reduced turbulence compared to an existing design.

  14. Design of an Adaptive Human-Machine System Based on Dynamical Pattern Recognition of Cognitive Task-Load

    Science.gov (United States)

    Zhang, Jianhua; Yin, Zhong; Wang, Rubin

    2017-01-01

    This paper developed a cognitive task-load (CTL) classification algorithm and allocation strategy to sustain the optimal operator CTL levels over time in safety-critical human-machine integrated systems. An adaptive human-machine system is designed based on a non-linear dynamic CTL classifier, which maps a set of electroencephalogram (EEG) and electrocardiogram (ECG) related features to a few CTL classes. The least-squares support vector machine (LSSVM) is used as dynamic pattern classifier. A series of electrophysiological and performance data acquisition experiments were performed on seven volunteer participants under a simulated process control task environment. The participant-specific dynamic LSSVM model is constructed to classify the instantaneous CTL into five classes at each time instant. The initial feature set, comprising 56 EEG and ECG related features, is reduced to a set of 12 salient features (including 11 EEG-related features) by using the locality preserving projection (LPP) technique. An overall correct classification rate of about 80% is achieved for the 5-class CTL classification problem. Then the predicted CTL is used to adaptively allocate the number of process control tasks between operator and computer-based controller. Simulation results showed that the overall performance of the human-machine system can be improved by using the adaptive automation strategy proposed. PMID:28367110

  15. Concurrent assessments of lower limb loading patterns, mechanical muscle strength and functional performance in ACL-patients - A cross-sectional study

    DEFF Research Database (Denmark)

    Holsgaard-Larsen, Anders; Jensen, C; Mortensen, N H M

    2014-01-01

    Full recovery in muscle strength and functional performance may not be achieved after ACL-injury. Aim: The aim of this study is to investigate loading patterns during jumping, muscle function and functional performance in ACL-reconstructed patients and to investigate the origin of between-limb...

  16. CAE process to simulate and optimise engine noise and vibration

    Science.gov (United States)

    Junhong, Zhang; Jun, Han

    2006-08-01

    The vibratory and acoustic behaviour of the internal combustion engine is a highly complex one, consisting of many components that are subject to loads that vary greatly in magnitude and which operate at wide range of speed. CAE tools development will lead to a significant reduction in the duration of the development period for engine as well as ensure a dramatic increase in product quality. This paper presents today's state-of-the-art CAE capabilities in the simulation of the dynamic and acoustic behaviour of engine and focuses on the relative merits of modification and full-scale structural/acoustic optimisation of engine, together with the creation of new low-noise designs. Modern CAE tools allow the analysis, assessment and acoustic optimisation of the engine.

  17. Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners.

    Science.gov (United States)

    An, W; Rainbow, M J; Cheung, R T H

    2015-01-01

    Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; -10°) with and without their usual running shoes. Vertical average rate (VALR) and instantaneous loading rate (VILR) were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p barefoot condition (p > 0.382). There was no difference (p > 0.413) in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p > 0.15). Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p < 0.011).

  18. Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners

    Directory of Open Access Journals (Sweden)

    W. An

    2015-01-01

    Full Text Available Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; −10° with and without their usual running shoes. Vertical average rate (VALR and instantaneous loading rate (VILR were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p0.382. There was no difference (p>0.413 in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p>0.15. Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p<0.011.

  19. Robust optimisation of railway crossing geometry

    Science.gov (United States)

    Wan, Chang; Markine, Valeri; Dollevoet, Rolf

    2016-05-01

    This paper presents a methodology for improving the crossing (frog) geometry through the robust optimisation approach, wherein the variability of the design parameters within a prescribed tolerance is included in the optimisation problem. Here, the crossing geometry is defined by parameterising the B-spline represented cross-sectional shape and the longitudinal height profile of the nose rail. The dynamic performance of the crossing is evaluated considering the variation of wheel profiles and track alignment. A multipoint approximation method (MAM) is applied in solving the optimisation problem of minimising the contact pressure during the wheel-rail contact and constraining the location of wheel transition at the crossing. To clarify the difference between the robust optimisation and the normal deterministic optimisation approaches, the optimisation problems are solved in both approaches. The results show that the deterministic optimum fails under slight change of the design variables; the robust optimum, however, has improved and robust performance.

  20. An Optimisation Approach for Room Acoustics Design

    DEFF Research Database (Denmark)

    Holm-Jørgensen, Kristian; Kirkegaard, Poul Henning; Andersen, Lars

    2005-01-01

    This paper discuss on a conceptual level the value of optimisation techniques in architectural acoustics room design from a practical point of view. It is chosen to optimise one objective room acoustics design criterium estimated from the sound field inside the room. The sound field is modeled...... using the boundary element method where absorption is incorporated. An example is given where the geometry of a room is defined by four design modes. The room geometry is optimised to get a uniform sound pressure....

  1. Advanced treatment planning using direct 4D optimisation for pencil-beam scanned particle therapy

    Science.gov (United States)

    Bernatowicz, Kinga; Zhang, Ye; Perrin, Rosalind; Weber, Damien C.; Lomax, Antony J.

    2017-08-01

    We report on development of a new four-dimensional (4D) optimisation approach for scanned proton beams, which incorporates both irregular motion patterns and the delivery dynamics of the treatment machine into the plan optimiser. Furthermore, we assess the effectiveness of this technique to reduce dose to critical structures in proximity to moving targets, while maintaining effective target dose homogeneity and coverage. The proposed approach has been tested using both a simulated phantom and a clinical liver cancer case, and allows for realistic 4D calculations and optimisation using irregular breathing patterns extracted from e.g. 4DCT-MRI (4D computed tomography-magnetic resonance imaging). 4D dose distributions resulting from our 4D optimisation can achieve almost the same quality as static plans, independent of the studied geometry/anatomy or selected motion (regular and irregular). Additionally, current implementation of the 4D optimisation approach requires less than 3 min to find the solution for a single field planned on 4DCT of a liver cancer patient. Although 4D optimisation allows for realistic calculations using irregular breathing patterns, it is very sensitive to variations from the planned motion. Based on a sensitivity analysis, target dose homogeneity comparable to static plans (D5-D95  <5%) has been found only for differences in amplitude of up to 1 mm, for changes in respiratory phase  <200 ms and for changes in the breathing period of  <20 ms in comparison to the motions used during optimisation. As such, methods to robustly deliver 4D optimised plans employing 4D intensity-modulated delivery are discussed.

  2. Optimisation combinatoire Theorie et algorithmes

    CERN Document Server

    Korte, Bernhard; Fonlupt, Jean

    2010-01-01

    Ce livre est la traduction fran aise de la quatri me et derni re dition de Combinatorial Optimization: Theory and Algorithms crit par deux minents sp cialistes du domaine: Bernhard Korte et Jens Vygen de l'universit de Bonn en Allemagne. Il met l accent sur les aspects th oriques de l'optimisation combinatoire ainsi que sur les algorithmes efficaces et exacts de r solution de probl mes. Il se distingue en cela des approches heuristiques plus simples et souvent d crites par ailleurs. L ouvrage contient de nombreuses d monstrations, concises et l gantes, de r sultats difficiles. Destin aux tudia

  3. Optimising resource management in neurorehabilitation.

    Science.gov (United States)

    Wood, Richard M; Griffiths, Jeff D; Williams, Janet E; Brouwers, Jakko

    2014-01-01

    To date, little research has been published regarding the effective and efficient management of resources (beds and staff) in neurorehabilitation, despite being an expensive service in limited supply. To demonstrate how mathematical modelling can be used to optimise service delivery, by way of a case study at a major 21 bed neurorehabilitation unit in the UK. An automated computer program for assigning weekly treatment sessions is developed. Queue modelling is used to construct a mathematical model of the hospital in terms of referral submissions to a waiting list, admission and treatment, and ultimately discharge. This is used to analyse the impact of hypothetical strategic decisions on a variety of performance measures and costs. The project culminates in a hybridised model of these two approaches, since a relationship is found between the number of therapy hours received each week (scheduling output) and length of stay (queuing model input). The introduction of the treatment scheduling program has substantially improved timetable quality (meaning a better and fairer service to patients) and has reduced employee time expended in its creation by approximately six hours each week (freeing up time for clinical work). The queuing model has been used to assess the effect of potential strategies, such as increasing the number of beds or employing more therapists. The use of mathematical modelling has not only optimised resources in the short term, but has allowed the optimality of longer term strategic decisions to be assessed.

  4. Dose optimisation in single plane interstitial brachytherapy

    DEFF Research Database (Denmark)

    Tanderup, Kari; Hellebust, Taran Paulsen; Honoré, Henriette Benedicte;

    2006-01-01

    BACKGROUND AND PURPOSE: Brachytherapy dose distributions can be optimised       by modulation of source dwell times. In this study dose optimisation in       single planar interstitial implants was evaluated in order to quantify the       potential benefit in patients. MATERIAL AND METHODS: In 14...

  5. Self-optimising control of sewer systems

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Montero-Castro, Ignacio; Mollerup, Ane Loft;

    The design of sewer system control is a complex task given the large size of the sewer networks, the transient dynamics of the water flows and the stochastic nature of rainfall. This contribution presents a generic methodology for the design of a self-optimising controller in sewer systems...... to design an optimising control strategy for a subcathcment area in Copenhagen....

  6. An Optimisation Approach for Room Acoustics Design

    DEFF Research Database (Denmark)

    Holm-Jørgensen, Kristian; Kirkegaard, Poul Henning; Andersen, Lars

    2005-01-01

    This paper discuss on a conceptual level the value of optimisation techniques in architectural acoustics room design from a practical point of view. It is chosen to optimise one objective room acoustics design criterium estimated from the sound field inside the room. The sound field is modeled...

  7. Haemodynamic optimisation in lower limb arterial surgery

    DEFF Research Database (Denmark)

    Bisgaard, J; Gilsaa, T; Rønholm, E;

    2012-01-01

    index was optimised by administering 250 ml aliquots of colloid intraoperatively and during the first 6 h post-operatively. Following surgery, fluid optimisation was supplemented with dobutamine, if necessary, targeting an oxygen delivery index level ≥ 600 ml/min(/) m(2) in the intervention group...

  8. Comparison of Anchorage Pattern under Two Types of Orthodontic Mini- Implant Loading During Retraction in Type A Anchorage Cases

    Science.gov (United States)

    Khan, B. Imran; Mandava, Prasad; Reddy, G. Vivek; Nettam, Venkatesh; Bhavikati, Venkat Naidu

    2016-01-01

    Introduction The orthodontic mini-screws are the mainstay of direct skeletal anchorage which requires minimal compliance and provides maximal anchorage control. However, the timing of initiation of orthodontic loading of these mini-screws is not clearly established in the available studies. Aim The purpose of this study was to determine the reciprocal effects on mini-screw implant with immediate loading in comparison to that of delayed loading during retraction. Materials and Methods The prospective clinical study included a sample of 25 orthodontic patients in the age range of 18-25 years. All the cases were of bi-maxillary proclination with Type-A anchorage demands. All the first premolars were indicated for extraction. A split mouth technique for each patient was utilized by loading mini-implant immediately after its placement on one side and the opposite side implant was loaded after a time lag of two weeks post-insertion. Retraction force of 150g was applied for three months on each side. The displacement of the head and tail of the implant, molar anterior tooth retraction was measured on Orthopantomograph (OPG) taken at T1 (initial) and T2 (after three months). A grid method with each 1mm magnified to 500 pixels was superimposed on OPG and the relative displacements were evaluated. Student’s unpaired ‘t’ test was used for comparison between left and right side and paired ‘t’ test for the parameters on the same side. The p-value equal to or less than 0.05 was taken as statistically significant. Results The mean displacement of head of the implant on the immediate loading is 0.57mm where as the tail exhibited 0.75 mm. The head and tail of the implant on the delayed loading displaced by 0.35mm and 0.38mm respectively, on an average when data was analysed. Significant difference between the two types of loading was noted. Conclusion Delayed loading is beneficial as compared to immediate loading during extraction space closure. PMID:27891469

  9. Evolutionary programming for neutron instrument optimisation

    Science.gov (United States)

    Bentley, Phillip M.; Pappas, Catherine; Habicht, Klaus; Lelièvre-Berna, Eddy

    2006-11-01

    Virtual instruments based on Monte-Carlo techniques are now integral part of novel instrumentation development and the existing codes (McSTAS and Vitess) are extensively used to define and optimise novel instrumental concepts. Neutron spectrometers, however, involve a large number of parameters and their optimisation is often a complex and tedious procedure. Artificial intelligence algorithms are proving increasingly useful in such situations. Here, we present an automatic, reliable and scalable numerical optimisation concept based on the canonical genetic algorithm (GA). The algorithm was used to optimise the 3D magnetic field profile of the NSE spectrometer SPAN, at the HMI. We discuss the potential of the GA which combined with the existing Monte-Carlo codes (Vitess, McSTAS, etc.) leads to a very powerful tool for automated global optimisation of a general neutron scattering instrument, avoiding local optimum configurations.

  10. Evolutionary programming for neutron instrument optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Bentley, Phillip M. [Hahn-Meitner Institut, Glienicker Strasse 100, D-14109 Berlin (Germany)]. E-mail: phillip.bentley@hmi.de; Pappas, Catherine [Hahn-Meitner Institut, Glienicker Strasse 100, D-14109 Berlin (Germany); Habicht, Klaus [Hahn-Meitner Institut, Glienicker Strasse 100, D-14109 Berlin (Germany); Lelievre-Berna, Eddy [Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France)

    2006-11-15

    Virtual instruments based on Monte-Carlo techniques are now integral part of novel instrumentation development and the existing codes (McSTAS and Vitess) are extensively used to define and optimise novel instrumental concepts. Neutron spectrometers, however, involve a large number of parameters and their optimisation is often a complex and tedious procedure. Artificial intelligence algorithms are proving increasingly useful in such situations. Here, we present an automatic, reliable and scalable numerical optimisation concept based on the canonical genetic algorithm (GA). The algorithm was used to optimise the 3D magnetic field profile of the NSE spectrometer SPAN, at the HMI. We discuss the potential of the GA which combined with the existing Monte-Carlo codes (Vitess, McSTAS, etc.) leads to a very powerful tool for automated global optimisation of a general neutron scattering instrument, avoiding local optimum configurations.

  11. Optimising costs in WLCG operations

    CERN Document Server

    Pradillo, Mar; Flix, Josep; Forti, Alessandra; Sciabà, Andrea

    2015-01-01

    The Worldwide LHC Computing Grid project (WLCG) provides the computing and storage resources required by the LHC collaborations to store, process and analyse the 50 Petabytes of data annually generated by the LHC. The WLCG operations are coordinated by a distributed team of managers and experts and performed by people at all participating sites and from all the experiments. Several improvements in the WLCG infrastructure have been implemented during the first long LHC shutdown to prepare for the increasing needs of the experiments during Run2 and beyond. However, constraints in funding will affect not only the computing resources but also the available effort for operations. This paper presents the results of a detailed investigation on the allocation of the effort in the different areas of WLCG operations, identifies the most important sources of inefficiency and proposes viable strategies for optimising the operational cost, taking into account the current trends in the evolution of the computing infrastruc...

  12. Optimising Comprehensibility in Interlingual Translation

    DEFF Research Database (Denmark)

    Nisbeth Jensen, Matilde

    2015-01-01

    . It is argued that Plain Language writing is a type of intralingual translation as it involves rewriting or translating a complex monolingual text into comprehensible language. Based on Plain Language literature, a comprehensibility framework is elaborated, which is subsequently exemplified through...... the functional text type of Patient Information Leaflet. Finally, the usefulness of applying the principles of Plain Language and intralingual translation for optimising comprehensibility in interlingual translation is discussed....... information on medication and tax information. Such texts are often written by experts and received by lay people, and, in today’s globalised world, they are often translated as well. In these functional texts, the receiver is not a mere recipient of information, but s/he needs to be able to act upon it...

  13. Using the internet of things to enable electrical load optimisation

    CSIR Research Space (South Africa)

    Butgereit, L

    2012-05-01

    Full Text Available . When a Resource Adaptor receives a message, it converts the message to a common format and forwards it to the Beachcomber routing facility. The routing facility refers to configuration tables and forwards the information to a... business process. The business processes are implemented as Mobicents Service Building Blocks (SBBs). These SBBs process the information and then send replies back to the routing facility which then forwards the replies to one or more...

  14. Real Time Load Optimisation of Cable Based Transmission Grids

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdottir, Unnur Stella

    2011-01-01

    Energinet.dk has launched an investigation of dynamic current ratings of cable based transmission grids, where both internal and external parameters are variables. The first topic was to investigate state of the art within calculating the current carrying capacity (ampacity or loadability...

  15. Evaluation of stress pattern generated through various thread designs of dental implants loaded in a condition of immediately after placement and on osseointegration--an FEA study.

    Science.gov (United States)

    Chowdhary, Ramesh; Halldin, Anders; Jimbo, Ryo; Wennerberg, Ann

    2013-02-01

    To determine the stress pattern generated through various thread design in experimental simulation models, when loaded immediately after placement and after osseointegration. Three-dimensional (3D) models were designed using CATIA, computer-aided design modeling software. The study was planned in 2 stages. Eight 2D models were constructed of different thread forms, one set with frictionless and other with bonded for bone to implant interface and loaded vertically with 100 N. In Stage II, 6 3D models of the different threads embedded in the cortical bone were constructed and loaded vertically and obliquely. In 2D models, the von Mises stress concentrated at the crest in the bonded connection thread designs. The stress levels were in the range of 7 to 13 MPa. In the frictional implant bone interface, the thread designs had a clear effect on the stress levels in the bone. In the 3D analysis, the complete implant design affected the stress levels. The thread design affects the magnitude of the stress peak in the bone more effectively in immediately loaded (frictionless) implants than the osseointegrated (bonded) implants. Maximum stress was observed at the first thread in most of the osseointegrated implants.

  16. Systematic delay-driven power optimisation and power-driven delay optimisation of combinational circuits

    OpenAIRE

    Mehrotra, Rashmi

    2013-01-01

    With the proliferation of mobile wireless communication and embedded systems, the energy efficiency becomes a major design constraint. The dissipated energy is often referred as the product of power dissipation and the input-output delay. Most of electronic design automation techniques focus on optimising only one of these parameters either power or delay. Industry standard design flows integrate systematic methods of optimising either area or timing while for power consumption optimisation o...

  17. Quantify work load and muscle functional activation patterns in neck-shoulder muscles of female sewing machine operators using surface electromyogram.

    Science.gov (United States)

    Zhang, Fei-Ruo; He, Li-Hua; Wu, Shan-Shan; Li, Jing-Yun; Ye, Kang-Pin; Wang, Sheng

    2011-11-01

    Work-related musculoskeletal disorders (WMSDs) have high prevalence in sewing machine operators employed in the garment industry. Long work duration, sustained low level work and precise hand work are the main risk factors of neck-shoulder disorders for sewing machine operators. Surface electromyogram (sEMG) offers a valuable tool to determine muscle activity (internal exposure) and quantify muscular load (external exposure). During sustained and/or repetitive muscle contractions, typical changes of muscle fatigue in sEMG, as an increase in amplitude or a decrease as a shift in spectrum towards lower frequencies, can be observed. In this paper, we measured and quantified the muscle load and muscular activity patterns of neck-shoulder muscles in female sewing machine operators during sustained sewing machine operating tasks using sEMG. A total of 18 healthy women sewing machine operators volunteered to participate in this study. Before their daily sewing machine operating task, we measured the maximal voluntary contractions (MVC) and 20%MVC of bilateral cervical erector spinae (CES) and upper trapezius (UT) respectively, then the sEMG signals of bilateral UT and CES were monitored and recorded continuously during 200 minutes of sustained sewing machine operating simultaneously which equals to 20 time windows with 10 minutes as one time window. After 200 minutes' work, we retest 20%MVC of four neck-shoulder muscles and recorded the sEMG signals. Linear analysis, including amplitude probability distribution frequency (APDF), amplitude analysis parameters such as roof mean square (RMS) and spectrum analysis parameter as median frequency (MF), were used to calculate and indicate muscle load and muscular activity of bilateral CES and UT. During 200 minutes of sewing machine operating, the median load for the left cervical erector spinae (LCES), right cervical erector spinae (RCES), left upper trapezius (LUT) and right upper trapezius (RUT) were 6.78%MVE, 6.94%MVE, 6

  18. Modeling of plug-in electric vehicle travel patterns and charging load based on trip chain generation

    Science.gov (United States)

    Wang, Dai; Gao, Junyu; Li, Pan; Wang, Bin; Zhang, Cong; Saxena, Samveg

    2017-08-01

    Modeling PEV travel and charging behavior is the key to estimate the charging demand and further explore the potential of providing grid services. This paper presents a stochastic simulation methodology to generate itineraries and charging load profiles for a population of PEVs based on real-world vehicle driving data. In order to describe the sequence of daily travel activities, we use the trip chain model which contains the detailed information of each trip, namely start time, end time, trip distance, start location and end location. A trip chain generation method is developed based on the Naive Bayes model to generate a large number of trips which are temporally and spatially coupled. We apply the proposed methodology to investigate the multi-location charging loads in three different scenarios. Simulation results show that home charging can meet the energy demand of the majority of PEVs in an average condition. In addition, we calculate the lower bound of charging load peak on the premise of lowest charging cost. The results are instructive for the design and construction of charging facilities to avoid excessive infrastructure.

  19. Benchmarks for dynamic multi-objective optimisation

    CSIR Research Space (South Africa)

    Helbig, M

    2013-06-01

    Full Text Available When algorithms solve dynamic multi-objective optimisation problems (DMOOPs), benchmark functions should be used to determine whether the algorithm can overcome specific difficulties that can occur in real-world problems. However, for dynamic multi...

  20. Topology optimisation for natural convection problems

    CERN Document Server

    Alexandersen, Joe; Andreasen, Casper Schousboe; Sigmund, Ole

    2014-01-01

    This paper demonstrates the application of the density-based topology optimisation approach for the design of heat sinks and micropumps based on natural convection effects. The problems are modelled under the assumptions of steady-state laminar flow using the incompressible Navier-Stokes equations coupled to the convection-diffusion equation through the Boussinesq approximation. In order to facilitate topology optimisation, the Brinkman approach is taken to penalise velocities inside the solid domain and the effective thermal conductivity is interpolated in order to accommodate differences in thermal conductivity of the solid and fluid phases. The governing equations are discretised using stabilised finite elements and topology optimisation is performed for two different problems using discrete adjoint sensitivity analysis. The study shows that topology optimisation is a viable approach for designing heat sink geometries cooled by natural convection and micropumps powered by natural convection.

  1. Topology Optimisation for Coupled Convection Problems

    DEFF Research Database (Denmark)

    Alexandersen, Joe

    This thesis deals with topology optimisation for coupled convection problems. The aim is to extend and apply topology optimisation to steady-state conjugate heat transfer problems, where the heat conduction equation governs the heat transfer in a solid and is coupled to thermal transport...... in a surrounding uid, governed by a convection-diffusion equation, where the convective velocity field is found from solving the isothermal incompressible steady-state Navier-Stokes equations. Topology optimisation is also applied to steady-state natural convection problems. The modelling is done using stabilised...... finite elements, the formulation and implementation of which was done partly during a special course as prepatory work for this thesis. The formulation is extended with a Brinkman friction term in order to facilitate the topology optimisation of fluid flow and convective cooling problems. The derived...

  2. An optimisation method for complex product design

    Science.gov (United States)

    Li, Ni; Yi, Wenqing; Bi, Zhuming; Kong, Haipeng; Gong, Guanghong

    2013-11-01

    Designing a complex product such as an aircraft usually requires both qualitative and quantitative data and reasoning. To assist the design process, a critical issue is how to represent qualitative data and utilise it in the optimisation. In this study, a new method is proposed for the optimal design of complex products: to make the full use of available data, information and knowledge, qualitative reasoning is integrated into the optimisation process. The transformation and fusion of qualitative and qualitative data are achieved via the fuzzy sets theory and a cloud model. To shorten the design process, parallel computing is implemented to solve the formulated optimisation problems. A parallel adaptive hybrid algorithm (PAHA) has been proposed. The performance of the new algorithm has been verified by a comparison with the results from PAHA and two other existing algorithms. Further, PAHA has been applied to determine the shape parameters of an aircraft model for aerodynamic optimisation purpose.

  3. User perspectives in public transport timetable optimisation

    DEFF Research Database (Denmark)

    Jensen, Jens Parbo; Nielsen, Otto Anker; Prato, Carlo Giacomo

    2014-01-01

    The present paper deals with timetable optimisation from the perspective of minimising the waiting time experienced by passengers when transferring either to or from a bus. Due to its inherent complexity, this bi-level minimisation problem is extremely difficult to solve mathematically, since...... on the large-scale public transport network in Denmark. The timetable optimisation approach yielded a yearly reduction in weighted waiting time equivalent to approximately 45 million Danish kroner (9 million USD)....

  4. Analysing bone regeneration using topological optimisation

    Directory of Open Access Journals (Sweden)

    Diego Alexander Garzón Alvarado

    2010-04-01

    Full Text Available The present article's object is to present the mathematical foundations of topological optimisation aimed at carrying out a study of bone regeneration. Bone structure can be economically adopted to different mechanical demands responding to topological optimisation models (having "minimum" mass and "high" resistance. Such analysis is essential for formulating physical therapy in patients needing partial or total strengthening of a particular bone's tissue structure. A mathematical model is formulated, as are the methods for resolving it.

  5. Optimisation of Fabric Reinforced Polymer Composites Using a Variant of Genetic Algorithm

    Science.gov (United States)

    Axinte, Andrei; Taranu, Nicolae; Bejan, Liliana; Hudisteanu, Iuliana

    2017-03-01

    Fabric reinforced polymeric composites are high performance materials with a rather complex fabric geometry. Therefore, modelling this type of material is a cumbersome task, especially when an efficient use is targeted. One of the most important issue of its design process is the optimisation of the individual laminae and of the laminated structure as a whole. In order to do that, a parametric model of the material has been defined, emphasising the many geometric variables needed to be correlated in the complex process of optimisation. The input parameters involved in this work, include: widths or heights of the tows and the laminate stacking sequence, which are discrete variables, while the gaps between adjacent tows and the height of the neat matrix are continuous variables. This work is one of the first attempts of using a Genetic Algorithm (GA) to optimise the geometrical parameters of satin reinforced multi-layer composites. Given the mixed type of the input parameters involved, an original software called SOMGA (Satin Optimisation with a Modified Genetic Algorithm) has been conceived and utilised in this work. The main goal is to find the best possible solution to the problem of designing a composite material which is able to withstand to a given set of external, in-plane, loads. The optimisation process has been performed using a fitness function which can analyse and compare mechanical behaviour of different fabric reinforced composites, the results being correlated with the ultimate strains, which demonstrate the efficiency of the composite structure.

  6. A multiobjective scatter search algorithm for fault-tolerant NoC mapping optimisation

    Science.gov (United States)

    Le, Qianqi; Yang, Guowu; Hung, William N. N.; Zhang, Xinpeng; Fan, Fuyou

    2014-08-01

    Mapping IP cores to an on-chip network is an important step in Network-on-Chip (NoC) design and affects the performance of NoC systems. A mapping optimisation algorithm and a fault-tolerant mechanism are proposed in this article. The fault-tolerant mechanism and the corresponding routing algorithm can recover NoC communication from switch failures, while preserving high performance. The mapping optimisation algorithm is based on scatter search (SS), which is an intelligent algorithm with a powerful combinatorial search ability. To meet the requests of the NoC mapping application, the standard SS is improved for multiple objective optimisation. This method helps to obtain high-performance mapping layouts. The proposed algorithm was implemented on the Embedded Systems Synthesis Benchmarks Suite (E3S). Experimental results show that this optimisation algorithm achieves low-power consumption, little communication time, balanced link load and high reliability, compared to particle swarm optimisation and genetic algorithm.

  7. System optimisation for automatic wood-fired heating systems; Systemoptimierung automatischer Holzheizung - Projektphase 1

    Energy Technology Data Exchange (ETDEWEB)

    Good, J.; Nussbaumer, T. [Verenum, Zuerich (Switzerland); Jenni, A. [Ardens GmbH, Liestal (Switzerland); Buehler, R. [Umwelt und Energie, Maschwanden (Switzerland)

    2002-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of the first phase of a project that is to optimise the performance of existing automatic wood-fired heating systems in the range 330 kW to 1 MW from the ecological and economical points of view. The report presents the results of an initial phase of the project in which five selected installations were optimised in order to be able to assess the potential for optimisation in general. The study looks at the efficiency of the plant as far as heat generation and distribution are concerned. The report presents details on various factors measured such as operating hours, heat distribution, control strategies, fuel-quality requirements, integration in heating systems and safety aspects and compares power delivered with rated power. The authors consider the potential for optimisation to be high and suggest optimisation targets concerning consumer density in district heating schemes, full-load operating hours, minimum yearly operational efficiency and the control of heating power.

  8. Optimising costs in WLCG operations

    Science.gov (United States)

    Alandes Pradillo, María; Dimou, Maria; Flix, Josep; Forti, Alessandra; Sciabà, Andrea

    2015-12-01

    The Worldwide LHC Computing Grid project (WLCG) provides the computing and storage resources required by the LHC collaborations to store, process and analyse the 50 Petabytes of data annually generated by the LHC. The WLCG operations are coordinated by a distributed team of managers and experts and performed by people at all participating sites and from all the experiments. Several improvements in the WLCG infrastructure have been implemented during the first long LHC shutdown to prepare for the increasing needs of the experiments during Run2 and beyond. However, constraints in funding will affect not only the computing resources but also the available effort for operations. This paper presents the results of a detailed investigation on the allocation of the effort in the different areas of WLCG operations, identifies the most important sources of inefficiency and proposes viable strategies for optimising the operational cost, taking into account the current trends in the evolution of the computing infrastructure and the computing models of the experiments.

  9. Implications of MODIS impression of aerosol loading over urban and rural settlements in Nigeria: Possible links to energy consumption patterns in the country

    Science.gov (United States)

    Dom Onyeuwaoma, Nnaemeka

    2016-07-01

    A study of aerosol loading patterns in some selected cities in Nigeria was carried out using MODIS, TOMS/OMI AND AIRS satellite imageries for a period of 10 years. The results showed that an aerosol optical depth (AOD) loading obtained ranged from 0.02-0.9, UV aerosol index (AI) and carbon monoxide (CO) results ranged from 1.32- 2.43 and 2.22-2.6 molecule/cm2, respectively. The CO data was used to infer the presence of carbonecous aerosols from biomass, fossil combustion and industrial activities. This result indicates that areas with higher AOD and AI do not correspond in high CO loading. From the HYSPLIT and HAT analysis conducted it showed that advection plays important role in the dispersion of aerosols. This implies that aerosols can reside in a place remote from where they are generated. Also, the high concentration of CO aerosol in the southern cities suggests a high rate of industrial pollution as a result of fossil fuel burning, vehicular emissions, high population density and gas flaring. Therefore, emphasis should be on the need to switch to renewable energy options as an alternative to fossil fuel. Furthermore, plans for mitigations should not be limited to industrialized cities only but extended to other cities which might be bearing the real brunt of industrial emissions as shown in this work.

  10. Seasonal patterns in immune indices reflect microbial loads on birds but not microbes in the wider environment

    NARCIS (Netherlands)

    Horrocks, N.P.C.; Matson, K.D.; Shobrak, M.; Tinbergen, J.M.; Tieleman, B.I.

    2012-01-01

    Documenting patterns in immune function is a first step to understanding immune variation, but to comprehend causes and consequences, antigen and parasite exposure that may drive such variation must be determined. We measured host-independent microbial exposure in five species of larks (Alaudidae) i

  11. Assessment of wind turbine load measurement instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Morfiadakis, E.; Papadopoulos, K. [CRES (Greece); Borg, N. van der [ECN, Petten (Netherlands); Petersen, S.M. [Risoe, Roskilde (Denmark); Seifert, H. [DEWI, Wilhelmshaven (Germany)

    1999-03-01

    In the framework of Sub-Task3 `Wind turbine load measurement instrumentation` of EU-project `European Wind Turbine Testing Procedure Development`, the load measurement techniques have been assessed by laboratory, full scale and numerical tests. The existing methods have been reviewed with emphasis on the strain gage application techniques on composite materials and recommendations are provided for the optimisation of load measurement techniques. (au) EU. 14 refs.

  12. Photovoltaic array capacity determined by considering the environmental factors for load patterns; Fuka pattern ni taisuru kankyo inshi wo koryoshita taiyo denchi array yoryo no kettei

    Energy Technology Data Exchange (ETDEWEB)

    Kameyama, N.; Higuchi, T.; Yamagami, Y.; Tani, T. [Science University of Tokyo, Tokyo (Japan). Faculty of Engineering

    1997-01-30

    Effectiveness of the spectral method was confirmed for system interconnection type photovoltaic (PV) power generation systems, and PV array capacity determined in harmony with the power load was investigated. In this study, system interconnection type PV power generation systems with polycrystalline Si and amorphous Si PV cell modules were discussed. The output electric energy evaluated by the spectral method was compared with that evaluated by the conventional method only considering the cell temperature. Obtained results are as follows. For the polycrystalline Si, the differences between solar supply rates in summer evaluated by the both methods and measured value were less than 2%, which resulted in the accurate determination. For the amorphous Si, however, the difference less than 3% was obtained by the spectral method and that less than 11% was obtained by the conventional method. The spectral method provided higher accuracy. When constructing a system with large array capacity, it was found that the optimum design of PV power generation system can be performed using the spectral method with less array capacity than using the conventional method. 4 refs., 9 figs., 4 tabs.

  13. Photovoltaic array capacity determined by considering the environmental factors for load patterns; Fuka pattern ni taisuru kankyo inshi wo koryoshita taiyo denchi array yoryo no kettei

    Energy Technology Data Exchange (ETDEWEB)

    Kameyama, N.; Higuchi, T.; Yamagami, Y.; Tani, T. [Science University of Tokyo, Tokyo (Japan). Faculty of Engineering

    1997-01-30

    Effectiveness of the spectral method was confirmed for system interconnection type photovoltaic (PV) power generation systems, and PV array capacity determined in harmony with the power load was investigated. In this study, system interconnection type PV power generation systems with polycrystalline Si and amorphous Si PV cell modules were discussed. The output electric energy evaluated by the spectral method was compared with that evaluated by the conventional method only considering the cell temperature. Obtained results are as follows. For the polycrystalline Si, the differences between solar supply rates in summer evaluated by the both methods and measured value were less than 2%, which resulted in the accurate determination. For the amorphous Si, however, the difference less than 3% was obtained by the spectral method and that less than 11% was obtained by the conventional method. The spectral method provided higher accuracy. When constructing a system with large array capacity, it was found that the optimum design of PV power generation system can be performed using the spectral method with less array capacity than using the conventional method. 4 refs., 9 figs., 4 tabs.

  14. Shape optimisation and performance analysis of flapping wings

    KAUST Repository

    Ghommem, Mehdi

    2012-09-04

    -averaged thrust, while the average aerodynamic power is increased. Furthermore, increasing the number of variables (i.e., providing the wing shape with greater degrees of spatial freedom) is observed to enable superior designs. To gain a better understanding of the reasons for which the obtained optimised shapes produce efficient flapping flights, the wake pattern and its vorticity strength are examined. This work described in this paper should facilitate better guidance for shape design of engineered flying systems.

  15. HYBRID GREY WOLF OPTIMIZATION-PATTERN SEARCH (hGWO-PS OPTIMIZED 2DOF-PID CONTROLLERS FOR LOAD FREQUENCY CONTROL (LFC IN INTERCONNECTED THERMAL POWER PLANTS

    Directory of Open Access Journals (Sweden)

    V Soni

    2016-04-01

    Full Text Available The combination of Grey Wolf Optimization and Pattern Search Technique (hGWO-PS has been introduced to optimize the parameters of two Degree of Freedom Proportional-Integral-Derivative Controller (2DOF-PID for controlling the load frequency in Automatic Generation Control (AGC for interconnected power system. The interconnected two area power system of non-reheat thermal power plants consisting of 2DOF-PID controller in each area has been considered for design and analysis. Firstly, the proposed approach has been implemented in the aforementioned standard test system and thereafter, the robustness of the system consisting 2DOF-PID controller optimized by proposed technique has been estimated using the sensitivity analysis for the same. The robustness of the system consisting of 2DOF-PID controller optimized by proposed scheme is examined by varying the parameters of standard test system, loading conditions during operation, size and location of the disturbances. The performance of the 2DOF-PID controller optimized by proposed approach has also been compared with recently published approaches in the literature. The simulation results show that the proposed hGWOPS optimized 2DOF-PID controller shows far better performance than recently published approaches in the literature in terms of dynamic response. The simulation results also show that system performances hardly change when the operating load condition and system parameters are changed by ±50% from their nominal values, i.e. the proposed controllers are quite robust for a wide range of the system parameters and operating load conditions from their nominal values.

  16. Sizing Combined Heat and Power Units and Domestic Building Energy Cost Optimisation

    Directory of Open Access Journals (Sweden)

    Dongmin Yu

    2017-06-01

    Full Text Available Many combined heat and power (CHP units have been installed in domestic buildings to increase energy efficiency and reduce energy costs. However, inappropriate sizing of a CHP may actually increase energy costs and reduce energy efficiency. Moreover, the high manufacturing cost of batteries makes batteries less affordable. Therefore, this paper will attempt to size the capacity of CHP and optimise daily energy costs for a domestic building with only CHP installed. In this paper, electricity and heat loads are firstly used as sizing criteria in finding the best capacities of different types of CHP with the help of the maximum rectangle (MR method. Subsequently, the genetic algorithm (GA will be used to optimise the daily energy costs of the different cases. Then, heat and electricity loads are jointly considered for sizing different types of CHP and for optimising the daily energy costs through the GA method. The optimisation results show that the GA sizing method gives a higher average daily energy cost saving, which is 13% reduction compared to a building without installing CHP. However, to achieve this, there will be about 3% energy efficiency reduction and 7% input power to rated power ratio reduction compared to using the MR method and heat demand in sizing CHP.

  17. Optimisation of Transmission Systems by use of Phase Shifting Transformers

    Energy Technology Data Exchange (ETDEWEB)

    Verboomen, J.

    2008-10-13

    In this thesis, transmission grids with PSTs (Phase Shifting Transformers) are investigated. In particular, the following goals are put forward: (a) The analysis and quantification of the impact of a PST on a meshed grid. This includes the development of models for the device; (b) The development of methods to obtain optimal coordination of several PSTs in a meshed grid. An objective function should be formulated, and an optimisation method must be adopted to solve the problem; and (c) The investigation of different strategies to use a PST. Chapter 2 gives a short overview of active power flow controlling devices. In chapter 3, a first step towards optimal PST coordination is taken. In chapter 4, metaheuristic optimisation methods are discussed. Chapter 5 introduces DC load flow approximations, leading to analytically closed equations that describe the relation between PST settings and active power flows. In chapter 6, some applications of the methods that are developed in earlier chapters are presented. Chapter 7 contains the conclusions of this thesis, as well as recommendations for future work.

  18. Variabilidad del patrón respiratorio durante la carga elástica inspiratoria Variability of breathing pattern during inspiratory elastic load

    Directory of Open Access Journals (Sweden)

    Carlos E. D´Negri

    2009-06-01

    Full Text Available La ventilación pulmonar en humanos tiene una variabilidad respiración a respiración no lineal, compleja y caótica. El objetivo del trabajo fue: caracterizar la variabilidad del patrón respiratorio en perros (n: 8 anestesiados respirando bajo carga elástica umbral (CEU inspiratoria (7 a 50 cm H2O. Con el flujo, presión traqueal y esofágica, se analizaron: tiempo inspiratorio (Ti, ritmo [tiempo espiratorio (Te; tiempo total (Ttot, y Ti/Ttot] e impulso central (Vt/Ti, variables relacionadas [volumen corriente (Vt y ventilación pulmonar (Ve]. Se determinaron: variabilidad grosera (varianzas, oscilaciones de baja frecuencia (análisis espectral y memoria a corto plazo (análisis de autocorrelación. La CEU produjo disminución de la varianza de medias en Te, Ttot, Vt y Vt/Ti (p In humans, lung ventilation exhibits breath-to-breath variability and dynamics that are nonlinear, complex and chaotic. Our objective was to characterize the breathing pattern variational activity in anesthetized dogs (n: 8 breathing through threshold inspiratory elastic load (7 to 50 cm H2O. Starting from flow signal and tracheal and esophageal pressures, we analyzed inspiratory time (Ti, timing (expiratory time, Te; total time, Ttot; and Ti/Ttot and central drive (Vt/Ti and variables related to it (tidal volume, Vt and pulmonary ventilation, Ve. We measured gross variability (variances, low frequency oscillations (spectral analysis, and short term memory (autocorrelation analysis. Loading decreased variance of the mean values of Te, Ttot, Vt and Vt/Ti (p < 0.05; the mean of variances for Ti/Ttot increased (p < 0.005 while it decreased for Vt and Vt/Ti (p < 0.05. In general, percent of data recordings with low frequency oscillations (OB% decreased (p < 0.02. During heavy load, timing parameters percent of data recordings with autocorrelations (AU% did not change, but Vt and its related parameters decreased their AU% (p < 0.005. There was a positive correlation (r: 0

  19. Optimisation Modelling of Efficiency of Enterprise Restructuring

    Directory of Open Access Journals (Sweden)

    Yefimova Hanna V.

    2014-03-01

    Full Text Available The article considers issues of optimisation of the use of resources directed at restructuring of a shipbuilding enterprise, which is the main prerequisite of its efficiency. Restructuring is considered as a process of complex and interconnected change in the structure of assets, liabilities, enterprise functions, initiated by dynamic environment, which is based on the strategic concept of its development and directed at increase of efficiency of its activity, which is expressed in the growth of cost. The task of making a decision to restructure a shipbuilding enterprise and selection of a specific restructuring project refers to optimisation tasks of prospective planning. Enterprise resources that are allocated for restructuring serve as constraints of the mathematical model. Main criteria of optimisation are maximisation of pure discounted income or minimisation of expenditures on restructuring measures. The formed optimisation model is designed for assessment of volumes of attraction of own and borrowed funds for restructuring. Imitation model ensures development of cash flows. The task solution is achieved on the basis of the complex of interrelated optimisation and imitation models and procedures on formation, selection and co-ordination of managerial decisions.

  20. Optimisation of Investment Resources at Small Enterprises

    Directory of Open Access Journals (Sweden)

    Shvets Iryna B.

    2014-03-01

    Full Text Available The goal of the article lies in the study of the process of optimisation of the structure of investment resources, development of criteria and stages of optimisation of volumes of investment resources for small enterprises by types of economic activity. The article characterises the process of transformation of investment resources into assets and liabilities of the balances of small enterprises and conducts calculation of the structure of sources of formation of investment resources in Ukraine at small enterprises by types of economic activity in 2011. On the basis of the conducted analysis of the structure of investment resources of small enterprises the article forms main groups of criteria of optimisation in the context of individual small enterprises by types of economic activity. The article offers an algorithm and step-by-step scheme of optimisation of investment resources at small enterprises in the form of a multi-stage process of management of investment resources in the context of increase of their mobility and rate of transformation of existing resources into investments. The prospect of further studies in this direction is development of a structural and logic scheme of optimisation of volumes of investment resources at small enterprises.

  1. Development of a model for optimisation of a power plant mix by means of evolution strategy; Modellentwicklung zur Kraftwerksparkoptimierung mit Hilfe von Evolutionsstrategien

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Hans

    2008-09-17

    Within the scope of this thesis a model based on evolution strategy is depicted, which optimises the upgrade of an existing power plant mix. In doing so the optimisation problem is divided in two sections covering the building of new power plants as well as their ideal usage within the persisting power plant mix. The building of new power plants is optimised by means of mutations, while their ideal usage is specified by a heuristic classification according to the merit order of the power plant mix. By applying a residual yearly load curve the consumer load can be modelled, incorporating the impact of fluctuating power generation and its probability of occurrence. Power plant failures and the duration of revisions are adequately considered by means of a power reduction factor. The optimisation furthermore accommodates a limiting threshold for yearly carbon dioxide emissions as well as a premature decommissioning of power plants. (orig.)

  2. Multicriteria Optimisation in Logistics Forwarder Activities

    Directory of Open Access Journals (Sweden)

    Tanja Poletan Jugović

    2007-05-01

    Full Text Available Logistics forwarder, as organizer and planner of coordinationand integration of all the transport and logistics chains elements,uses adequate ways and methods in the process of planningand decision-making. One of these methods, analysed inthis paper, which could be used in optimisation of transportand logistics processes and activities of logistics forwarder, isthe multicriteria optimisation method. Using that method, inthis paper is suggested model of multicriteria optimisation of logisticsforwarder activities. The suggested model of optimisationis justified in keeping with method principles of multicriteriaoptimization, which is included in operation researchmethods and it represents the process of multicriteria optimizationof variants. Among many different processes of multicriteriaoptimization, PROMETHEE (Preference Ranking OrganizationMethod for Enrichment Evaluations and Promcalc& Gaia V. 3.2., computer program of multicriteria programming,which is based on the mentioned process, were used.

  3. Topology Optimisation for Coupled Convection Problems

    DEFF Research Database (Denmark)

    Alexandersen, Joe; Andreasen, Casper Schousboe; Aage, Niels

    conduction governs in the solid parts of the design domain and couples to convection-dominated heat transfer to a surrounding fluid. Both loosely coupled and tightly coupled problems are considered. The loosely coupled problems are convection-diffusion problems, based on an advective velocity field from......The work focuses on applying topology optimisation to forced and natural convection problems in fluid dynamics and conjugate (fluid-structure) heat transfer. To the authors' knowledge, topology optimisation has not yet been applied to natural convection flow problems in the published literature...... and the current work is thus seen as contributing new results to the field. In the literature, most works on the topology optimisation of weakly coupled convection-diffusion problems focus on the temperature distribution of the fluid, but a selection of notable exceptions also focusing on the temperature...

  4. Optimisation of arbitrary light beam generation with spatial light modulators

    Science.gov (United States)

    Radwell, Neal; Offer, Rachel F.; Selyem, Adam; Franke-Arnold, Sonja

    2017-09-01

    Phase only spatial light modulators (SLMs) have become the tool of choice for shaped light generation, allowing the creation of arbitrary amplitude and phase patterns. These patterns are generated using digital holograms and are useful for a wide range of applications as well as for fundamental research. There have been many proposed methods for optimal generation of the digital holograms, all of which perform well under ideal conditions. Here we test a range of these methods under specific experimental constraints, by varying grating period, filter size, hologram resolution, number of phase levels, phase throw and phase nonlinearity. We model beam generation accuracy and efficiency and show that our results are not limited to the specific beam shapes, but should hold for general beam shaping. Our aim is to demonstrate how to optimise and improve the performance of phase-only SLMs for experimentally relevant implementations.

  5. Quantify work load and muscle functional activation patterns in neck-shoulder muscles of female sewing machine operators using surface electromyogram

    Institute of Scientific and Technical Information of China (English)

    ZHANG Fei-ruo; HE Li-hua; WU Shan-shan; LI Jing-yun; YE Kang-pin; WANG Sheng

    2011-01-01

    Background Work-related musculoskeletal disorders (WMSDs) have high prevalence in sewing machine operators employed in the garment industry.Long work duration,sustained low level work and precise hand work are the main risk factors of neck-shoulder disorders for sewing machine operators.Surface electromyogram (sEMG) offers a valuable tool to determine muscle activity (internal exposure) and quantify muscular load (external exposure).During sustained and/or repetitive muscle contractions,typical changes of muscle fatigue in sEMG,as an increase in amplitude or a decrease as a shift in spectrum towards lower frequencies,can be observed.In this paper,we measured and quantified the muscle load and muscular activity patterns of neck-shoulder muscles in female sewing machine operators during sustained sewing machine operating tasks using sEMG.Methods A total of 18 healthy women sewing machine operators volunteered to participate in this study.Before their daily sewing machine operating task,we measured the maximal voluntary contractions (MVC) and 20%MVC of bilateral cervical erector spinae (CES) and upper trapezius (UT) respectively,then the sEMG signals of bilateral UT and CES were monitored and recorded continuously during 200 minutes of sustained sewing machine operating simultaneously which equals to 20 time windows with 10 minutes as one time window.After 200 minutes' work,we retest 20%MVC of four neck-shoulder muscles and recorded the sEMG signals.Linear analysis,including amplitude probability distribution frequency (APDF),amplitude analysis parameters such as roof mean square (RMS) and spectrum analysis parameter as median frequency (MF),were used to calculate and indicate muscle load and muscular activity of bilateral CES and UT.Results During 200 minutes of sewing machine operating,the median load for the left cervical erector spinae (LCES),right cervical erector spinae (RCES),left upper trapezius (LUT) and right upper trapezius (RUT) were 6.78%MVE,6.94

  6. Differential Patterns and Determinants of Cardiac Autonomic Nerve Dysfunction during Endotoxemia and Oral Fat Load in Humans.

    Directory of Open Access Journals (Sweden)

    Dan Ziegler

    Full Text Available The autonomic nervous system (ANS plays an important role in regulating the metabolic homeostasis and controlling immune function. ANS alterations can be detected by reduced heart rate variability (HRV in conditions like diabetes and sepsis. We determined the effects of experimental conditions mimicking inflammation and hyperlipidemia on HRV and heart rate (HR in relation to the immune, metabolic, and hormonal responses resulting from these interventions. Sixteen lean healthy subjects received intravenous (i.v. low-dose endotoxin (lipopolysaccharide [LPS], i.v. fat, oral fat, and i.v. glycerol (control for 6 hours, during which immune, metabolic, hormonal, and five HRV parameters (pNN50, RMSSD, low-frequency (LF and high-frequency (HF power, and LF/HF ratio were monitored and energy metabolism and insulin sensitivity (M-value were assessed. LPS infusion induced an increase (AUC in HR and LF/HF ratio and decline in pNN50 and RMSSD, while oral fat resulted in elevated HR and a transient (hours 1-2 decrease in pNN50, RMSSD, and HF power. During LPS infusion, ΔIL-1ra levels and ΔIL-1ra and ΔIL-1ß gene expression correlated positively with ΔLF/HF ratio and inversely with ΔRMSSD. During oral fat intake, ΔGLP-1 tended to correlate positively with ΔHR and inversely with ΔpNN50 and ΔRMSSD. Following LPS infusion, lipid oxidation correlated positively with HR and inversely with pNN50 and RMSSD, whereas HRV was not related to M-value. In conclusion, suppression of vagal tone and sympathetic predominance during endotoxemia are linked to anti-inflammatory processes and lipid oxidation but not to insulin resistance, while weaker HRV changes in relation to the GLP-1 response are noted during oral fat load.ClinicalTrials.gov NCT01054989.

  7. Differential Patterns and Determinants of Cardiac Autonomic Nerve Dysfunction during Endotoxemia and Oral Fat Load in Humans

    Science.gov (United States)

    Ziegler, Dan; Strom, Alexander; Strassburger, Klaus; Nowotny, Bettina; Zahiragic, Lejla; Nowotny, Peter J.; Carstensen-Kirberg, Maren; Herder, Christian; Szendroedi, Julia; Roden, Michael

    2015-01-01

    The autonomic nervous system (ANS) plays an important role in regulating the metabolic homeostasis and controlling immune function. ANS alterations can be detected by reduced heart rate variability (HRV) in conditions like diabetes and sepsis. We determined the effects of experimental conditions mimicking inflammation and hyperlipidemia on HRV and heart rate (HR) in relation to the immune, metabolic, and hormonal responses resulting from these interventions. Sixteen lean healthy subjects received intravenous (i.v.) low-dose endotoxin (lipopolysaccharide [LPS]), i.v. fat, oral fat, and i.v. glycerol (control) for 6 hours, during which immune, metabolic, hormonal, and five HRV parameters (pNN50, RMSSD, low-frequency (LF) and high-frequency (HF) power, and LF/HF ratio) were monitored and energy metabolism and insulin sensitivity (M-value) were assessed. LPS infusion induced an increase (AUC) in HR and LF/HF ratio and decline in pNN50 and RMSSD, while oral fat resulted in elevated HR and a transient (hours 1-2) decrease in pNN50, RMSSD, and HF power. During LPS infusion, ΔIL-1ra levels and ΔIL-1ra and ΔIL-1ß gene expression correlated positively with ΔLF/HF ratio and inversely with ΔRMSSD. During oral fat intake, ΔGLP-1 tended to correlate positively with ΔHR and inversely with ΔpNN50 and ΔRMSSD. Following LPS infusion, lipid oxidation correlated positively with HR and inversely with pNN50 and RMSSD, whereas HRV was not related to M-value. In conclusion, suppression of vagal tone and sympathetic predominance during endotoxemia are linked to anti-inflammatory processes and lipid oxidation but not to insulin resistance, while weaker HRV changes in relation to the GLP-1 response are noted during oral fat load. Trial Registration ClinicalTrials.gov NCT01054989 PMID:25893426

  8. Do Orientation-Based Differences in Nestbox Temperature Cause Differential Ectoparasite Load and Explain Patterns of Nest-Site Selection and Offspring Condition in Great Tits?

    Directory of Open Access Journals (Sweden)

    Anne E. Goodenough

    2011-01-01

    Full Text Available Nest ectoparasites have been linked previously to patterns of nest-site choice and breeding success in birds. Recent research has shown nestboxes facing south-southwest are occupied less frequently by great tits (Parus major than identical boxes facing other directions, and are associated with reduced offspring condition. Here, we investigate the hypothesis that these findings are due to ectoparasite load being directionally nonuniform, possibly because of nonuniformity in nestbox internal temperature. Nests contained, in order of prevalence, hen fleas (Ceratophyllus gallinae, haematophagous blowflies (Protocalliphora spp., biting lice (Ischnocera, and ticks/mites (Acari. Although southwest-facing nestboxes were significantly warmer than other boxes, there was no directional difference in total ectoparasite load or abundance of particular species. Similarly, there was no relationship between abundance of any ectoparasite species (either per-nest or per-chick and avian offspring condition determined using wing length or relative mass. We discuss several possible, nonmutually exclusive, explanations for this, including compensatory responses, costs of parasitism being transferred to parents, and condition-dependent effects.

  9. [Process optimisation: from theory to practical implementation].

    Science.gov (United States)

    Töpfer, Armin

    2010-01-01

    Today process optimisation is an indispensable approach to mastering the current challenges of modern health care management. The objective is to design business processes free of defects and free of waste as well as their monitoring and controlling with meaningful test statistics. Based on the identification of essential key performance indicators, key success factors and value cash generators two basic approaches to process optimisation, which are well-established and widely used in the industry, are now being implemented in the health care sector as well: Lean Management and Six Sigma.

  10. Simulating stem growth using topological optimisation

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Narváez

    2010-04-01

    Full Text Available Engineers are currently resorting to observations of nature for making new designs. Studying the functioning of bodies of plants and animals has required them to be modelled and simulated; however, some models born from engineering problems could be used for such purposes. This article shows how topological optimisation (a mathematical model for optimising designing structural elements can be used for modeling and simulating the way a stem grows in terms of carrying out its funtion of providing support for the leaves and a plant's other upper organs.

  11. Bat Algorithm for Multi-objective Optimisation

    CERN Document Server

    Yang, Xin-She

    2012-01-01

    Engineering optimization is typically multiobjective and multidisciplinary with complex constraints, and the solution of such complex problems requires efficient optimization algorithms. Recently, Xin-She Yang proposed a bat-inspired algorithm for solving nonlinear, global optimisation problems. In this paper, we extend this algorithm to solve multiobjective optimisation problems. The proposed multiobjective bat algorithm (MOBA) is first validated against a subset of test functions, and then applied to solve multiobjective design problems such as welded beam design. Simulation results suggest that the proposed algorithm works efficiently.

  12. Topology Optimisation of Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Thike Aye Min

    2016-01-01

    Full Text Available Wireless sensor networks are widely used in a variety of fields including industrial environments. In case of a clustered network the location of cluster head affects the reliability of the network operation. Finding of the optimum location of the cluster head, therefore, is critical for the design of a network. This paper discusses the optimisation approach, based on the brute force algorithm, in the context of topology optimisation of a cluster structure centralised wireless sensor network. Two examples are given to verify the approach that demonstrate the implementation of the brute force algorithm to find an optimum location of the cluster head.

  13. Viral Load Pattern Among Hepatitis B Surface Antigen-positive Patients: Laboratory Perspective and Implications for Therapy

    Science.gov (United States)

    Iregbu, KC; Nwajiobi-Princewill, PI

    2016-01-01

    Background: Hepatitis B viral infection is an old medical problem with worldwide distribution. It is usually diagnosed using serologic methods. However, the decision as to which patient to treat or not remains challenging due to the poor sensitivity of serologic markers as prognostic or severity markers. Viral load (VL) determination using polymerase chain reaction techniques is a useful tool in decision-making. Aim: To determine the proportion of hepatitis B-positive patients who fall into different care groups based on the Society for Gastroenterology and Hepatology in Nigeria (SOGHIN) and National Institute for Health and Care Excellence guidelines, respectively, using result of hepatitis B virus (HBV) DNA determination. Materials and Methods: This is a retrospective and descriptive study. Data from all patients sent to the medical microbiology laboratory, National Hospital Abuja over a period of 28 months (November 2012 to February 2015) for hepatitis B DNA VL determinations were analyzed using Microsoft Excel 2010 (Microsoft Corporation, Redmond, WA, USA) and IBM SPSS version 20.0 (IBM SPSS, Inc., Chicago, IL, USA). Results: A total 666 patients, with mean age of 33.2 years, were tested. For those whose ages were known 36.2% (100/276) were below 30 years and 63.8% (176/276) 30 years and above. Exactly 66.7% (444/666) were males and the remaining 33.3% (222/666) were females. The VL of the patients varied from 20 to 1.7 × 108 IU/ml, with an average of 3.5 × 106 IU/ml. Around 76.1% (507/666) had measurable assay levels (20 − 1.7 × 108 IU/ml); 10.8% (76/666) had below 20 IU/ml and 3.8% (25/666) above 1.7 × 108 IU/ml. About 9.3% (62/666) had no detectable HBV DNA in their samples. About 46.8% (312/666) of the patients had levels between 20 and 2 × 103 IU/ml; 16.4% (109/666) had between 2001 and 2 × 104 IU/ml while 16.7% (111/666) had VL of between 20,001 and 1.7 × 108 IU/ml. Males tended to have detectable and higher VLs than females (P = 0

  14. Optimisation of interventional cardiology procedures; Optimisation des procedures en cardiologie interventionnelle

    Energy Technology Data Exchange (ETDEWEB)

    Bar, Olivier [SELARL, Cardiologie Interventionnelle Imagerie Cardiaque - CIIC, 8, place de la Cathedrale - 37042 Tours (France)

    2011-07-15

    Radiation-guided procedures in interventional cardiology include diagnostic and/or therapeutic procedures, primarily coronary catheterization and coronary angioplasty. Application of the principles of radiation protection and the use of optimised procedures are contributing to dose reduction while maintaining the radiological image quality necessary for performance of the procedures. The mandatory training in patient radiation protection and technical training in the use of radiology devices mean that implementing continuous optimisation of procedures is possible in practice. This optimisation approach is the basis of patient radiation protection; when associated with the wearing of protective equipment it also contributes to the radiation protection of the cardiologists. (author)

  15. Extending Particle Swarm Optimisers with Self-Organized Criticality

    DEFF Research Database (Denmark)

    Løvbjerg, Morten; Krink, Thiemo

    2002-01-01

    Particle swarm optimisers (PSOs) show potential in function optimisation, but still have room for improvement. Self-organized criticality (SOC) can help control the PSO and add diversity. Extending the PSO with SOC seems promising reaching faster convergence and better solutions.......Particle swarm optimisers (PSOs) show potential in function optimisation, but still have room for improvement. Self-organized criticality (SOC) can help control the PSO and add diversity. Extending the PSO with SOC seems promising reaching faster convergence and better solutions....

  16. Metabolic approaches for the optimisation of recombinant fermentation processes.

    Science.gov (United States)

    Cserjan-Puschmann, M; Kramer, W; Duerrschmid, E; Striedner, G; Bayer, K

    1999-12-01

    The aim of this work was the establishment of a novel method to determine the metabolic load on host-cell metabolism resulting from recombinant protein production in Escherichia coli. This tool can be used to develop strategies to optimise recombinant fermentation processes through adjustment of recombinant-protein expression to the biosynthetic capacity of the host-cell. The signal molecule of the stringent-response network, guanosine tetraphosphate (ppGpp), and its precursor nucleotides were selected for the estimation of the metabolic load relating to recombinant-protein production. An improved analytical method for the quantification of nucleotides by ion-pair, high-performance liquid chromatography was established. The host-cell response upon overexpression of recombinant protein in fed-batch fermentations was investigated using the production of human superoxide dismutase (rhSOD) as a model system. E. coli strains with different recombinant systems (the T7 and pKK promoter system) exerting different loads on host-cell metabolism were analysed with regard to intracellular nucleotide concentration, rate of product formation and plasmid copy number.

  17. Particle Swarm Optimisation with Spatial Particle Extension

    DEFF Research Database (Denmark)

    Krink, Thiemo; Vesterstrøm, Jakob Svaneborg; Riget, Jacques

    2002-01-01

    In this paper, we introduce spatial extension to particles in the PSO model in order to overcome premature convergence in iterative optimisation. The standard PSO and the new model (SEPSO) are compared w.r.t. performance on well-studied benchmark problems. We show that the SEPSO indeed managed...

  18. Topology optimisation of natural convection problems

    DEFF Research Database (Denmark)

    Alexandersen, Joe; Aage, Niels; Andreasen, Casper Schousboe

    2014-01-01

    This paper demonstrates the application of the density-based topology optimisation approach for the design of heat sinks and micropumps based on natural convection effects. The problems are modelled under the assumptions of steady-state laminar flow using the incompressible Navier-Stokes equation...

  19. Thermodynamic optimisation of a heat exchanger

    NARCIS (Netherlands)

    Cornelissen, R.L.; Hirs, G.G.

    1999-01-01

    The objective of this paper is to show that for the optimal design of an energy system, where there is a trade-off between exergy saving during operation and exergy use during construction of the energy system, exergy analysis and life cycle analysis should be combined. An exergy optimisation of a h

  20. Optimised Design of Transparent Optical Domains

    DEFF Research Database (Denmark)

    Hanik, N.; Caspar, C.; Schmidt, F.;

    2000-01-01

    Three different design concepts for transparent, dispersion compensated, optical WDM transmission links are optimised numerically and experimentally for 10 Gbit/s data rate per channel. It is shown that robust transparent domains of 1,500 km in diameter can be realised using simple design rutes....

  1. Minimisation of the wall shear stress gradients in bypass grafts anastomoses using meshless CFD and genetic algorithms optimisation.

    Science.gov (United States)

    El Zahab, Zaher; Divo, Eduardo; Kassab, Alain

    2010-02-01

    The wall shear stress (WSS) spatial and temporal gradients are two hemodynamics parameters correlated with endothelial damage. Those two gradients become well pronounced in a bypass graft anastomosis geometry where the blood flow patterns are quite disturbed. The WSS gradient minimisation on the host artery floor can be achieved by optimising the anastomosis shape and hence may lead to an improved long-term post-surgical performance of the graft. The anastomosis shape optimisation can be executed via an integrated computational tool comprised of a meshless computational fluid dynamics (CFD) solver and a genetic algorithm (GA) shape optimiser. The meshless CFD solver serves to evaluate the WSS gradients and the GA optimiser serves to search for the end-to-side distal anastomosis (ETSDA) optimal shape that best minimises those gradients. We utilise a meshless CFD method to resolve hemodynamics and a GA for the purpose of optimisation. We consider three different anastomotic models: the conventional ETSDA, the Miller Cuff ETSDA and the hood ETSDA. The results reported herein demonstrate that the graft calibre should always be maximised whether a conventional or Miller Cuff ETSDA model is utilised. Also, it was noted that the Miller Cuff height should be minimised. The choice of an optimal anastomotic angle should be optimised to achieve a compromise between the concurrent minimisations of both the spatial WSS gradient and the temporal WSS gradient.

  2. The Okinawan diet: health implications of a low-calorie, nutrient-dense, antioxidant-rich dietary pattern low in glycemic load.

    Science.gov (United States)

    Willcox, D Craig; Willcox, Bradley J; Todoriki, Hidemi; Suzuki, Makoto

    2009-08-01

    Residents of Okinawa, the southernmost prefecture of Japan, are known for their long average life expectancy, high numbers of centenarians, and accompanying low risk of age-associated diseases. Much of the longevity advantage in Okinawa is thought to be related to a healthy lifestyle, particularly the traditional diet, which is low in calories yet nutritionally dense, especially with regard to phytonutrients in the form of antioxidants and flavonoids. Research suggests that diets associated with a reduced risk of chronic diseases are similar to the traditional Okinawan diet, that is, vegetable and fruit heavy (therefore phytonutrient and antioxidant rich) but reduced in meat, refined grains, saturated fat, sugar, salt, and full-fat dairy products. Many of the characteristics of the diet in Okinawa are shared with other healthy dietary patterns, such as the traditional Mediterranean diet or the modern DASH (Dietary Approaches to Stop Hypertension) diet. Features such as the low levels of saturated fat, high antioxidant intake, and low glycemic load in these diets are likely contributing to a decreased risk for cardiovascular disease, some cancers, and other chronic diseases through multiple mechanisms, including reduced oxidative stress. A comparison of the nutrient profiles of the three dietary patterns shows that the traditional Okinawan diet is the lowest in fat intake, particularly in terms of saturated fat, and highest in carbohydrate intake, in keeping with the very high intake of antioxidant-rich yet calorie-poor orange-yellow root vegetables, such as sweet potatoes, and green leafy vegetables. Deeper analyses of the individual components of the Okinawan diet reveal that many of the traditional foods, herbs, or spices consumed on a regular basis could be labeled "functional foods" and, indeed, are currently being explored for their potential health-enhancing properties.

  3. GIS-based approach for optimised collection of household waste in Mostaganem city (Western Algeria).

    Science.gov (United States)

    Abdelli, I S; Abdelmalek, F; Djelloul, A; Mesghouni, K; Addou, A

    2016-05-01

    This work proposes an optimisation of municipal solid waste collection in terms of collection cost and polluting emissions (carbon oxides, carbon dioxides, nitrogen oxides and particulate matter). This method is based on a simultaneous optimisation of the vehicles routing (distance and time travelled) and the routing system for household wastes collection based on the existing network of containers, the capacity of vehicles and the quantities generated in every collecting point. The process of vehicle routing optimisation involves a geographical information system. This optimisation has enabled a reduction of travelled distances, collection time, fuel consumption and polluting emissions. Pertinent parameters affecting the fuel consumption have been utilised, such as the state of the road, the vehicles speed in the different paths, the vehicles load and collection frequencies. Several scenarios have been proposed. The results show the importance of the construction of a waste transfer station that can reduce the cost of household waste collection and emissions of waste transfer pollutants. Among the proposed five scenarios, we have noticed that the fourth scenario (by constructing a waste transfer centre) was the most performing. So, the routes of optimised travelled distance of the new circuits have been reduced by 71.81%. The fuel consumption has been reduced by 72.05% and the total cost of the collection has been reduced by 46.8%. For the polluting emissions, the reduction has been by 60.2% for carbon oxides, by 67.9% for carbon dioxides, by 74.2% for nitrogen oxides and by 65% for particulate matter.

  4. Differential neural activation patterns in patients with Parkinson's disease and freezing of gait in response to concurrent cognitive and motor load.

    Directory of Open Access Journals (Sweden)

    James M Shine

    Full Text Available Freezing of gait is a devastating symptom of Parkinson's disease (PD that is exacerbated by the processing of cognitive information whilst walking. To date, no studies have explored the neural correlates associated with increases in cognitive load whilst performing a motor task in patients with freezing. In this experiment, 14 PD patients with and 15 PD patients without freezing of gait underwent 3T fMRI while performing a virtual reality gait task. Directions to walk and stop were presented on the viewing screen as either direct cues or as more cognitively indirect pre-learned cues. Both groups showed a consistent pattern of BOLD response within the Cognitive Control Network during performance of the paradigm. However, a between group comparison revealed that those PD patients with freezing of gait were less able to recruit the bilateral anterior insula, ventral striatum and the pre-supplementary motor area, as well as the left subthalamic nucleus when responding to indirect cognitive cues whilst maintaining a motor output. These results suggest that PD patients with freezing of gait are unable to properly recruit specific cortical and subcortical regions within the Cognitive Control Network during the performance of simultaneous motor and cognitive functions.

  5. Differential Neural Activation Patterns in Patients with Parkinson's Disease and Freezing of Gait in Response to Concurrent Cognitive and Motor Load

    Science.gov (United States)

    Shine, James M.; Matar, Elie; Ward, Philip B.; Bolitho, Samuel J.; Pearson, Mark; Naismith, Sharon L.; Lewis, Simon J. G.

    2013-01-01

    Freezing of gait is a devastating symptom of Parkinson's disease (PD) that is exacerbated by the processing of cognitive information whilst walking. To date, no studies have explored the neural correlates associated with increases in cognitive load whilst performing a motor task in patients with freezing. In this experiment, 14 PD patients with and 15 PD patients without freezing of gait underwent 3T fMRI while performing a virtual reality gait task. Directions to walk and stop were presented on the viewing screen as either direct cues or as more cognitively indirect pre-learned cues. Both groups showed a consistent pattern of BOLD response within the Cognitive Control Network during performance of the paradigm. However, a between group comparison revealed that those PD patients with freezing of gait were less able to recruit the bilateral anterior insula, ventral striatum and the pre-supplementary motor area, as well as the left subthalamic nucleus when responding to indirect cognitive cues whilst maintaining a motor output. These results suggest that PD patients with freezing of gait are unable to properly recruit specific cortical and subcortical regions within the Cognitive Control Network during the performance of simultaneous motor and cognitive functions. PMID:23382821

  6. The Pattern of Brain Amyloid Load in Posterior Cortical Atrophy Using 18F-AV45: Is Amyloid the Principal Actor in the Disease

    Directory of Open Access Journals (Sweden)

    Emilie Beaufils

    2014-11-01

    Full Text Available Background: Posterior cortical atrophy (PCA is characterized by progressive higher-order visuoperceptual dysfunction and praxis declines. This syndrome is related to a number of underlying diseases, including, in most cases, Alzheimer's disease (AD. The aim of this study was to compare the amyloid load with 18F-AV45 positron emission tomography (PET between PCA and AD subjects. Methods: We performed 18F-AV45 PET, cerebrospinal fluid (CSF biomarker analysis and a neuropsychological assessment in 11 PCA patients and 12 AD patients. Results: The global and regional 18F-AV45 uptake was similar in the PCA and AD groups. No significant correlation was observed between global 18F-AV45 uptake and CSF biomarkers or between regional 18F-AV45 uptake and cognitive and affective symptoms. Conclusion: This 18F-AV45 PET amyloid imaging study showed no specific regional pattern of cortical 18F-AV45 binding in PCA patients. These results confirm that a distinct clinical phenotype in amnestic AD and PCA is not related to amyloid distribution.

  7. Public transport optimisation emphasising passengers’ travel behaviour

    DEFF Research Database (Denmark)

    Jensen, Jens Parbo

    to enhance the operations of public transport while explicitly emphasising passengers’ travel behaviour and preferences. Similar to economic theory, interactions between supply and demand are omnipresent in the context of public transport operations. In public transport, the demand is represented...... the published performance measures and what passengers actually experience, a large academic contribution of the current PhD study is the explicit consideration of passengers’ travel behaviour in optimisation studies and in the performance assessment. Besides the explicit passenger focus in transit planning...... at as the motivator for delay-robust railway timetables. Interestingly, passenger oriented optimisation studies considering robustness in railway planning typically limit their emphasis on passengers to the consideration of transfer maintenance. Clearly, passengers’ travel behaviour is more complex and multifaceted...

  8. Topology optimised planar photonic crystal building blocks

    DEFF Research Database (Denmark)

    Frandsen, Lars Hagedorn; Hede, K. K.; Borel, Peter Ingo

    A photonic crystal waveguide (PhCW) 1x4 splitter has been constructed from PhCW 60° bends1 and Y-splitters2 that have been designed individually by utilising topology optimisation3. The splitter has been fabricated in a silicon-on-insulator material (Fig. 1) and exhibits a broadband splitting...... for the TE-polarisation with an average excess loss of 1.55±0.54 dB for a 110 nm bandwidth. The 1x4 splitter demonstrates that individual topology-optimised parts can be used as building blocks to realise high-performance nanophotonic circuits. 1L. H. Frandsen et al., Opt. Express 12, 5916-5921 (2004) 2P. I...

  9. Self-optimising control of sewer systems

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Montero-Castro, I.; Mollerup, Ane Loft

    2013-01-01

    Self-optimising control is a useful concept to select optimal controlled variables from a set of candidate measurements in a systematic manner. In this study, use self-optimizing control tools and apply them to the specific features of sewer systems, e.g. the continuously transient dynamics......, the availability of a large number of measurements, the stochastic and unforeseeable character of the disturbances (rainfall). Using a subcatchment area in the Copenhagen sewer system as a case study we demonstrate, step by step, the formulation of the self-optimising control problem. The final result...... is an improved control structure aimed at optimizing the losses for a given control objective, here the minimization of the combined sewer overflows despite rainfall variations....

  10. Improved Squeaky Wheel Optimisation for Driver Scheduling

    CERN Document Server

    Aickelin, Uwe; Li, Jingpeng

    2008-01-01

    This paper presents a technique called Improved Squeaky Wheel Optimisation for driver scheduling problems. It improves the original Squeaky Wheel Optimisations effectiveness and execution speed by incorporating two additional steps of Selection and Mutation which implement evolution within a single solution. In the ISWO, a cycle of Analysis-Selection-Mutation-Prioritization-Construction continues until stopping conditions are reached. The Analysis step first computes the fitness of a current solution to identify troublesome components. The Selection step then discards these troublesome components probabilistically by using the fitness measure, and the Mutation step follows to further discard a small number of components at random. After the above steps, an input solution becomes partial and thus the resulting partial solution needs to be repaired. The repair is carried out by using the Prioritization step to first produce priorities that determine an order by which the following Construction step then schedul...

  11. Applying the Theory of Optimising Professional Life

    Directory of Open Access Journals (Sweden)

    Lesley Margaret Piko

    2014-12-01

    Full Text Available Glaser (2014 wrote that “the application of grounded theory (GT is a relatively neglected topic” (p. 1 in the literature. Applying GT to purposely intervene and improve a situation is an important adjunct to our knowledge and understanding of GT. A recent workshop of family doctors and general practitioners provides a useful example. The theory of optimising professional life explains that doctors are concerned about sustainment in their career and, to resolve this concern, they implement solutions to optimise their personal situation. Sustainment is a new, overarching concept of three needs: the need for self-care to sustain well-being, the need for work interest to sustain motivation, and the need for income to sustain lifestyle. The objective of the workshop was to empower doctors to reinvent their careers using this theory. Working individually and in small groups, participants were able to analyse a problem and to identify potential solutions.

  12. Fermionic orbital optimisation in tensor network states

    CERN Document Server

    Krumnow, C; Eisert, J

    2015-01-01

    Tensor network states and specifically matrix-product states have proven to be a powerful tool for simulating ground states of strongly correlated spin models. Recently, they have also been applied to interacting fermionic problems, specifically in the context of quantum chemistry. A new freedom arising in such non-local fermionic systems is the choice of orbitals, it being far from clear what choice of fermionic orbitals to make. In this work, we propose a way to overcome this challenge. We suggest a method intertwining the optimisation over matrix product states with suitable fermionic Gaussian mode transformations, hence bringing the advantages of both approaches together. The described algorithm generalises basis changes in the spirit of the Hartree-Fock methods to matrix-product states, and provides a black box tool for basis optimisations in tensor network methods.

  13. Adaptive Java Optimisation using machine learning techniques

    OpenAIRE

    Long, Shun

    2004-01-01

    There is a continuing demand for higher performance, particularly in the area of scientific and engineering computation. In order to achieve high performance in the context of frequent hardware upgrading, software must be adaptable for portable performance. What is required is an optimising compiler that evolves and adapts itself to environmental change without sacrificing performance. Java has emerged as a dominant programming language widely used in a variety of application areas. Howeve...

  14. ATLAS software configuration and build tool optimisation

    Science.gov (United States)

    Rybkin, Grigory; Atlas Collaboration

    2014-06-01

    ATLAS software code base is over 6 million lines organised in about 2000 packages. It makes use of some 100 external software packages, is developed by more than 400 developers and used by more than 2500 physicists from over 200 universities and laboratories in 6 continents. To meet the challenge of configuration and building of this software, the Configuration Management Tool (CMT) is used. CMT expects each package to describe its build targets, build and environment setup parameters, dependencies on other packages in a text file called requirements, and each project (group of packages) to describe its policies and dependencies on other projects in a text project file. Based on the effective set of configuration parameters read from the requirements files of dependent packages and project files, CMT commands build the packages, generate the environment for their use, or query the packages. The main focus was on build time performance that was optimised within several approaches: reduction of the number of reads of requirements files that are now read once per package by a CMT build command that generates cached requirements files for subsequent CMT build commands; introduction of more fine-grained build parallelism at package task level, i.e., dependent applications and libraries are compiled in parallel; code optimisation of CMT commands used for build; introduction of package level build parallelism, i. e., parallelise the build of independent packages. By default, CMT launches NUMBER-OF-PROCESSORS build commands in parallel. The other focus was on CMT commands optimisation in general that made them approximately 2 times faster. CMT can generate a cached requirements file for the environment setup command, which is especially useful for deployment on distributed file systems like AFS or CERN VMFS. The use of parallelism, caching and code optimisation significantly-by several times-reduced software build time, environment setup time, increased the efficiency of

  15. Optimised polarisation measurements on Bragg peaks

    Energy Technology Data Exchange (ETDEWEB)

    Lelievre-Berna, E. [Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)]. E-mail: lelievre@ill.fr; Brown, P.J. [Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Tasset, F. [Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2007-07-15

    Experimentally the asymmetry A (or the flipping ratio R) is deduced from the two count rates observed for |+> and |-> neutron spin states. Since the count rates for the two spin states may be quite different and both require to be corrected for background, the optimum strategy for the measurement is important. We present here the theory for optimisation of the accuracy of measurement of A (or R) within the constraint of a fixed total measuring time.

  16. Exploration of automatic optimisation for CUDA programming

    KAUST Repository

    Al-Mouhamed, Mayez

    2014-09-16

    © 2014 Taylor & Francis. Writing optimised compute unified device architecture (CUDA) program for graphic processing units (GPUs) is complex even for experts. We present a design methodology for a restructuring tool that converts C-loops into optimised CUDA kernels based on a three-step algorithm which are loop tiling, coalesced memory access and resource optimisation. A method for finding possible loop tiling solutions with coalesced memory access is developed and a simplified algorithm for restructuring C-loops into an efficient CUDA kernel is presented. In the evaluation, we implement matrix multiply (MM), matrix transpose (M-transpose), matrix scaling (M-scaling) and matrix vector multiply (MV) using the proposed algorithm. We present the analysis of the execution time and GPU throughput for the above applications, which favourably compare to other proposals. Evaluation is carried out while scaling the problem size and running under a variety of kernel configurations. The obtained speedup is about 28-35% for M-transpose compared to NVIDIA Software Development Kit, 33% speedup for MV compared to general purpose computation on graphics processing unit compiler, and more than 80% speedup for MM and M-scaling compared to CUDA-lite.

  17. Designing Lead Optimisation of MMP-12 Inhibitors

    Directory of Open Access Journals (Sweden)

    Matteo Borrotti

    2014-01-01

    Full Text Available The design of new molecules with desired properties is in general a very difficult problem, involving heavy experimentation with high investment of resources and possible negative impact on the environment. The standard approach consists of iteration among formulation, synthesis, and testing cycles, which is a very long and laborious process. In this paper we address the so-called lead optimisation process by developing a new strategy to design experiments and modelling data, namely, the evolutionary model-based design for optimisation (EDO. This approach is developed on a very small set of experimental points, which change in relation to the response of the experimentation according to the principle of evolution and insights gained through statistical models. This new procedure is validated on a data set provided as test environment by Pickett et al. (2011, and the results are analysed and compared to the genetic algorithm optimisation (GAO as a benchmark. The very good performance of the EDO approach is shown in its capacity to uncover the optimum value using a very limited set of experimental points, avoiding unnecessary experimentation.

  18. Optimisation of substrate blends in anaerobic co-digestion using adaptive linear programming.

    Science.gov (United States)

    García-Gen, Santiago; Rodríguez, Jorge; Lema, Juan M

    2014-12-01

    Anaerobic co-digestion of multiple substrates has the potential to enhance biogas productivity by making use of the complementary characteristics of different substrates. A blending strategy based on a linear programming optimisation method is proposed aiming at maximising COD conversion into methane, but simultaneously maintaining a digestate and biogas quality. The method incorporates experimental and heuristic information to define the objective function and the linear restrictions. The active constraints are continuously adapted (by relaxing the restriction boundaries) such that further optimisations in terms of methane productivity can be achieved. The feasibility of the blends calculated with this methodology was previously tested and accurately predicted with an ADM1-based co-digestion model. This was validated in a continuously operated pilot plant, treating for several months different mixtures of glycerine, gelatine and pig manure at organic loading rates from 1.50 to 4.93 gCOD/Ld and hydraulic retention times between 32 and 40 days at mesophilic conditions.

  19. Procedure for Application-Oriented Optimisation of Marine Propellers

    Directory of Open Access Journals (Sweden)

    Florian Vesting

    2016-11-01

    Full Text Available The use of automated optimisation in engineering applications is emerging. In particular, nature inspired algorithms are frequently used because of their variability and robust application in constraints and multi-objective optimisation problems. The purpose of this paper is the comparison of four different algorithms and several optimisation strategies on a set of seven test propellers in realistic industrial design setting. The propellers are picked from real commercial projects and the manual final designs were delivered to customers. The different approaches are evaluated and final results of the automated optimisation toolbox are compared with designs generated in a manual design process. We identify a two-stage optimisation for marine propellers, where the geometry is first modified by parametrised geometry distribution curves to gather knowledge of the test case. Here we vary the optimisation strategy in terms of applied algorithms, constraints and objectives. A second supporting optimisation aims to improve the design by locally changing the geometry, based on the results of the first optimisation. The optimisation algorithms and strategies yield propeller designs that are comparable to the manually designed propeller blade geometries, thus being suitable as robust and advanced design support tools. The supporting optimisation, with local modification of the blade geometry and the proposed cavity shape constraints, features particular good performance in modifying cavitation on the blade and is, with the AS NSGA-II (adaptive surrogate-assisted NSGA-II, superior in lead time.

  20. Railway vehicle performance optimisation using virtual homologation

    Science.gov (United States)

    Magalhães, H.; Madeira, J. F. A.; Ambrósio, J.; Pombo, J.

    2016-09-01

    Unlike regular automotive vehicles, which are designed to travel in different types of roads, railway vehicles travel mostly in the same route during their life cycle. To accept the operation of a railway vehicle in a particular network, a homologation process is required according to local standard regulations. In Europe, the standards EN 14363 and UIC 518, which are used for railway vehicle acceptance, require on-track tests and/or numerical simulations. An important advantage of using virtual homologation is the reduction of the high costs associated with on-track tests by studying the railway vehicle performance in different operation conditions. This work proposes a methodology for the improvement of railway vehicle design with the objective of its operation in selected railway tracks by using optimisation. The analyses required for the vehicle improvement are performed under control of the optimisation method global and local optimisation using direct search. To quantify the performance of the vehicle, a new objective function is proposed, which includes: a Dynamic Performance Index, defined as a weighted sum of the indices obtained from the virtual homologation process; the non-compensated acceleration, which is related to the operational velocity; and a penalty associated with cases where the vehicle presents an unacceptable dynamic behaviour according to the standards. Thus, the optimisation process intends not only to improve the quality of the vehicle in terms of running safety and ride quality, but also to increase the vehicle availability via the reduction of the time for a journey while ensuring its operational acceptance under the standards. The design variables include the suspension characteristics and the operational velocity of the vehicle, which are allowed to vary in an acceptable range of variation. The results of the optimisation lead to a global minimum of the objective function in which the suspensions characteristics of the vehicle are

  1. Automatic optimisation of gamma dose rate sensor networks: The DETECT Optimisation Tool

    DEFF Research Database (Denmark)

    Helle, K.B.; Müller, T.O.; Astrup, Poul;

    2014-01-01

    chosen using regular grids or according to administrative constraints. Nowadays, however, the choice can be based on more realistic risk assessment, as it is possible to simulate potential radioactive plumes. To support sensor planning, we developed the DETECT Optimisation Tool (DOT) within the scope...... monitoring network for early detection of radioactive plumes or for the creation of dose maps. The DOT is implemented as a stand-alone easy-to-use JAVA-based application with a graphical user interface and an R backend. Users can run evaluations and optimisations, and display, store and download the results...

  2. Real-time optimisation of the Hoa Binh reservoir, Vietnam

    DEFF Research Database (Denmark)

    Richaud, Bertrand; Madsen, Henrik; Rosbjerg, Dan

    2011-01-01

    -time optimisation. First, the simulation-optimisation framework is applied for optimising reservoir operating rules. Secondly, real-time and forecast information is used for on-line optimisation that focuses on short-term goals, such as flood control or hydropower generation, without compromising the deviation......Multi-purpose reservoirs often have to be managed according to conflicting objectives, which requires efficient tools for trading-off the objectives. This paper proposes a multi-objective simulation-optimisation approach that couples off-line rule curve optimisation with on-line real...... of the forecast is addressed. The results illustrate the importance of a sufficient forecast lead time to start pre-releasing water in flood situations....

  3. Methods for Optimisation of the Laser Cutting Process

    DEFF Research Database (Denmark)

    Dragsted, Birgitte

    This thesis deals with the adaptation and implementation of various optimisation methods, in the field of experimental design, for the laser cutting process. The problem in optimising the laser cutting process has been defined and a structure for at Decision Support System (DSS......) for the optimisation of the laser cutting process has been suggested. The DSS consists of a database with the currently used and old parameter settings. Also one of the optimisation methods has been implemented in the DSS in order to facilitate the optimisation procedure for the laser operator. The Simplex Method has...... been adapted in two versions. A qualitative one, that by comparing the laser cut items optimise the process and a quantitative one that uses a weighted quality response in order to achieve a satisfactory quality and after that maximises the cutting speed thus increasing the productivity of the process...

  4. Fuzzy Pattern Recognition Technique for Moving Train Loads Identification According to Bridge Responses%根据响应识别桥上列车荷载的模糊模式识别方法

    Institute of Scientific and Technical Information of China (English)

    瞿伟廉; 王仪

    2011-01-01

    为准确快速地获知通过桥梁的列车荷载大小,将模糊模式识别的方法引入桥梁列车荷载识别问题,将列车荷载识别过程转变为与列车荷载响应标准模式库的模式匹配过程.采用数值分析方法,分别基于桥梁位移、速度和加速度响应对鄱阳湖连续钢桁桥列车荷载进行识别,结果表明利用加速度响应获得的识别结果精度要明显好于采用位移和速度响应获得的识别精度,同时通过对在噪声干扰下列车荷载识别结果的分析,验证论文所述方法对桥上移动列车荷载进行识别的可行性和准确性.%A fuzzy pattern recognition method is presented to realize the accurate and efficient identification of moving train loads according to bridge responses. The moving loads identification process is translated into a procedure of pattern match with those in the load-response pattern library. Numerical simulations based on the responses of displacement,velocity and acceleration are carried out for Poyang Lake continuous steel-truss girder, and the train loads on the bridge are identified. It is shown that the results of identification by using acceleration response have higher accuracy than those obtained by using the others. Through the identification of the train loads with noise disturbance, this method is proved to be feasible and accurate for moving train loads identification.

  5. Low Proviral Load is Associated with Indeterminate Western Blot Patterns in Human T-Cell Lymphotropic Virus Type 1 Infected Individuals: Could Punctual Mutations be Related?

    Science.gov (United States)

    Cánepa, Camila; Salido, Jimena; Ruggieri, Matías; Fraile, Sindy; Pataccini, Gabriela; Berini, Carolina; Biglione, Mirna

    2015-10-28

    indeterminate Western blot (WB) patterns are a major concern for diagnosis of human T-cell lymphotropic virus type 1 (HTLV-1) infection, even in non-endemic areas. (a) to define the prevalence of indeterminate WB among different populations from Argentina; (b) to evaluate if low proviral load (PVL) is associated with indeterminate WB profiles; and (c) to describe mutations in LTR and tax sequence of these cases. Among 2031 samples, 294 were reactive by screening. Of them, 48 (16.3%) were WB indeterminate and of those 15 (31.3%) were PCR+. Quantitative real-time PCR (qPCR) was performed to 52 HTLV-1+ samples, classified as Group 1 (G1): 25 WB+ samples from individuals with pathologies; Group 2 (G2): 18 WB+ samples from asymptomatic carriers (AC); and Group 3 (G3): 9 seroindeterminate samples from AC. Median PVL was 4.78, 2.38, and 0.15 HTLV-1 copies/100 PBMCs, respectively; a significant difference (p=0.003) was observed. Age and sex were associated with PVL in G1 and G2, respectively. Mutations in the distal and central regions of Tax Responsive Elements (TRE) 1 and 2 of G3 were observed, though not associated with PVL.The 8403A>G mutation of the distal region, previously related to high PVL, was absent in G3 but present in 50% of WB+ samples (p = 0.03). indeterminate WB results confirmed later as HTLV-1 positive may be associated with low PVL levels. Mutations in LTR and tax are described; their functional relevance remains to be determined.

  6. Cumulative viral load and virologic decay patterns after antiretroviral therapy in HIV-infected subjects influence CD4 recovery and AIDS.

    Directory of Open Access Journals (Sweden)

    Vincent C Marconi

    Full Text Available BACKGROUND: The impact of viral load (VL decay and cumulative VL on CD4 recovery and AIDS after highly-active antiretroviral therapy (HAART is unknown. METHODS AND FINDINGS: Three virologic kinetic parameters (first year and overall exponential VL decay constants, and first year VL slope and cumulative VL during HAART were estimated for 2,278 patients who initiated HAART in the U.S. Military HIV Natural History Study. CD4 and VL trajectories were computed using linear and nonlinear Generalized Estimating Equations models. Multivariate Poisson and linear regression models were used to determine associations of VL parameters with CD4 recovery, adjusted for factors known to correlate with immune recovery. Cumulative VL higher than the sample median was independently associated with an increased risk of AIDS (relative risk 2.38, 95% confidence interval 1.56-3.62, p<0.001. Among patients with VL suppression, first year VL decay and slope were independent predictors of early CD4 recovery (p = 0.001 and overall gain (p<0.05. Despite VL suppression, those with slow decay during the first year of HAART as well as during the entire therapy period (overall, in general, gained less CD4 cells compared to the other subjects (133 vs. 195.4 cells/µL; p = 0.001 even after adjusting for potential confounders. CONCLUSIONS: In a cohort with free access to healthcare, independent of established predictors of AIDS and CD4 recovery during HAART, cumulative VL and virologic decay patterns were associated with AIDS and distinct aspects of CD4 reconstitution.

  7. Low Proviral Load is Associated with Indeterminate Western Blot Patterns in Human T-Cell Lymphotropic Virus Type 1 Infected Individuals: Could Punctual Mutations be Related?

    Directory of Open Access Journals (Sweden)

    Camila Cánepa

    2015-10-01

    Full Text Available Background: indeterminate Western blot (WB patterns are a major concern for diagnosis of human T-cell lymphotropic virus type 1 (HTLV-1 infection, even in non-endemic areas. Objectives: (a to define the prevalence of indeterminate WB among different populations from Argentina; (b to evaluate if low proviral load (PVL is associated with indeterminate WB profiles; and (c to describe mutations in LTR and tax sequence of these cases. Results: Among 2031 samples, 294 were reactive by screening. Of them, 48 (16.3% were WB indeterminate and of those 15 (31.3% were PCR+. Quantitative real-time PCR (qPCR was performed to 52 HTLV-1+ samples, classified as Group 1 (G1: 25 WB+ samples from individuals with pathologies; Group 2 (G2: 18 WB+ samples from asymptomatic carriers (AC; and Group 3 (G3: 9 seroindeterminate samples from AC. Median PVL was 4.78, 2.38, and 0.15 HTLV-1 copies/100 PBMCs, respectively; a significant difference (p=0.003 was observed. Age and sex were associated with PVL in G1 and G2, respectively. Mutations in the distal and central regions of Tax Responsive Elements (TRE 1 and 2 of G3 were observed, though not associated with PVL.The 8403A>G mutation of the distal region, previously related to high PVL, was absent in G3 but present in 50% of WB+ samples (p = 0.03. Conclusions: indeterminateWBresults confirmed later as HTLV-1 positive may be associated with low PVL levels. Mutations in LTR and tax are described; their functional relevance remains to be determined.

  8. Design Optimisation and Conrol of a Pilot Operated Seat Valve

    DEFF Research Database (Denmark)

    Nielsen, Brian; Andersen, Torben Ole; Hansen, Michael Rygaard

    2004-01-01

    The paper gives an approach for optimisation of the bandwidth of a pilot operated seat valve for mobile applications. Physical dimensions as well as parameters of the implemented control loop are optimised simultaneously. The frequency response of the valve varies as a function of the pressure drop...... across the valve, and it is found to be necessary to scale the controller parameters in the optimised design as a function of pressure drop....

  9. Mechatronic System Design Based On An Optimisation Approach

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Pedersen, Henrik Clemmensen; Hansen, Michael Rygaard

    The envisaged objective of this paper project is to extend the current state of the art regarding the design of complex mechatronic systems utilizing an optimisation approach. We propose to investigate a novel framework for mechatronic system design. The novelty and originality being the use...... of optimisation techniques. The methods used to optimise/design within the classical disciplines will be identified and extended to mechatronic system design....

  10. Topology optimisation for energy management in underwater sensor networks

    Science.gov (United States)

    Jha, Devesh K.; Wettergren, Thomas A.; Ray, Asok; Mukherjee, Kushal

    2015-09-01

    In general, battery-powered sensors in a sensor network are operable as long as they can communicate sensed data to a processing node. In this context, a sensor network has two competing objectives: (1) maximisation of the network performance with respect to the probability of successful search for a specified upper bound on the probability of false alarms, and (2) maximisation of the network's operable life. As both sensing and communication of data consume battery energy at the sensing nodes of the sensor network, judicious use of sensing power and communication power is needed to improve the lifetime of the sensor network. This paper presents an adaptive energy management policy that will optimally allocate the available energy between sensing and communication at each sensing node to maximise the network performance subject to specified constraints. Under the assumptions of fixed total energy allocation for a sensor network operating for a specified time period, the problem is reduced to synthesis of an optimal network topology that maximises the probability of successful search (of a target) over a surveillance region. In a two-stage optimisation, a genetic algorithm-based meta-heuristic search is first used to efficiently explore the global design space, and then a local pattern search algorithm is used for convergence to an optimal solution. The results of performance optimisation are generated on a simulation test bed to validate the proposed concept. Adaptation to energy variations across the network is shown to be manifested as a change in the optimal network topology by using sensing and communication models for underwater environment. The approximate Pareto-optimal surface is obtained as a trade-off between network lifetime and probability of successful search over the surveillance region.

  11. Improving Vector Evaluated Particle Swarm Optimisation by incorporating nondominated solutions.

    Science.gov (United States)

    Lim, Kian Sheng; Ibrahim, Zuwairie; Buyamin, Salinda; Ahmad, Anita; Naim, Faradila; Ghazali, Kamarul Hawari; Mokhtar, Norrima

    2013-01-01

    The Vector Evaluated Particle Swarm Optimisation algorithm is widely used to solve multiobjective optimisation problems. This algorithm optimises one objective using a swarm of particles where their movements are guided by the best solution found by another swarm. However, the best solution of a swarm is only updated when a newly generated solution has better fitness than the best solution at the objective function optimised by that swarm, yielding poor solutions for the multiobjective optimisation problems. Thus, an improved Vector Evaluated Particle Swarm Optimisation algorithm is introduced by incorporating the nondominated solutions as the guidance for a swarm rather than using the best solution from another swarm. In this paper, the performance of improved Vector Evaluated Particle Swarm Optimisation algorithm is investigated using performance measures such as the number of nondominated solutions found, the generational distance, the spread, and the hypervolume. The results suggest that the improved Vector Evaluated Particle Swarm Optimisation algorithm has impressive performance compared with the conventional Vector Evaluated Particle Swarm Optimisation algorithm.

  12. Robust Optimisation Approach for Vehicle Routing Problems with Uncertainty

    Directory of Open Access Journals (Sweden)

    Liang Sun

    2015-01-01

    Full Text Available We formulated a solution procedure for vehicle routing problems with uncertainty (VRPU for short with regard to future demand and transportation cost. Unlike E-SDROA (expectation semideviation robust optimisation approach for solving the proposed problem, the formulation focuses on robust optimisation considering situations possibly related to bidding and capital budgets. Besides, numerical experiments showed significant increments in the robustness of the solutions without much loss in solution quality. The differences and similarities of the robust optimisation model and existing robust optimisation approaches were also compared.

  13. Biorefinery plant design, engineering and process optimisation

    DEFF Research Database (Denmark)

    Holm-Nielsen, Jens Bo; Ehimen, Ehiazesebhor Augustine

    2014-01-01

    applicable for the planning and upgrading of intended biorefinery systems, and includes discussions on the operation of an existing lignocellulosic-based biorefinery platform. Furthermore, technical considerations and tools (i.e., process analytical tools) which could be applied to optimise the operations......Before new biorefinery systems can be implemented, or the modification of existing single product biomass processing units into biorefineries can be carried out, proper planning of the intended biorefinery scheme must be performed initially. This chapter outlines design and synthesis approaches...

  14. SIROCCO. Silent rotors by acoustic optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Schepers, J.G.; Curvers, A. [ECN Wind Energy, Petten (Netherlands); Oerlemans, S. [National Aerospace Laboratory NLR, Amsterdam (Netherlands); Braun, K.; Lutz, T.; Herrig, A.; Wuerz, W. [University of Stuttgart, Stuttgart (Germany); Matesanz, A.; Garcillan, L. [Gamesa Eolica, Madrid (Spain); Fisher, M.; Koegler, K.; Maeder, T. [GE Wind Energy/GE Global Research (United States)

    2007-07-15

    In this paper the results from the European 5th Framework project 'SIROCCO' are described. The project started in January 2003 and will end in August 2007. The main aim of the SIROCCO project is to reduce wind-turbine aerodynamic noise significantly while maintaining the aerodynamic performance. This is achieved by designing new acoustically and aerodynamically optimised airfoils for the outer part of the blade. The project focussed primarily on reducing trailing edge noise, which was broadly believed to be the dominant noise mechanism of modern wind turbines.

  15. Bionic Optimisation of the Earthquake Resistance of High Buildings by Tuned Mass Dampers

    Institute of Scientific and Technical Information of China (English)

    Rolf Steinbuch

    2011-01-01

    The optimisation of earthquake resistance of high buildings by multi-tuned mass dampers was investigated using bionic algorithms. In bionic or evolutionary optimisation studies the properties of parents are crossed and mutated to produce a new generation with slightly different properties. The kids which best satisfy the object of the study, become the parents of the next generation. After a series of generations essential improvements of the object may be observed. Tuned mass dampers are widely used to reduce the impact of dynamic excitations on structures. A single mass system and multi-mass oscillators help to explain the mechanics of the dampers. To apply the bionic optimisation strategy to high buildings with passive tuned mass dampers subject to seismic loading a special beam element has been developed. In addition to the 6 degrees of freedom of a conventional beam element, it has 2 degrees of freedom for the displacements of the dampers. It allows for fast studies of many variants. As central result, efficient designs for damping systems along the height of an edifice are found. The impact on the structure may be reduced essentially by the use of such dampers designed to interact in an optimal way.

  16. Multi-parameter building thermal analysis using the lattice method for global optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Saporito, A. [Fire and Environmental Modelling Centre, Building Research Establishment, Watford (United Kingdom); Day, A.R.; Karayiannis, T.G. [School of Engineering Systems and Design, South Bank University, London (United Kingdom); Parand, F. [Centre for Construction IT, Building Research Establishment, Watford (United Kingdom)

    2000-07-01

    The energy performance in buildings is a complex function of the building form and structure, heating system, occupancy pattern, operating schedules, and external climatic conditions. Computer simulations can help understand the dynamic interactions of these parameters. However, to carry out a multi-parameter analysis for the optimisation of the building energy performance, it is necessary to reduce the large number of tests resulting from all possible parameter combinations. In this paper, the lattice method for global optimisation (LMGO) for reducing the number of tests was used. A multi-parameter study was performed to investigate the heating energy use in office buildings using the thermal simulation code APACHE (IES-FACET). From the results of the sensitivity analysis it was possible to estimate the relative importance of various energy saving features. (author)

  17. Ant Colony Optimisation for Backward Production Scheduling

    Directory of Open Access Journals (Sweden)

    Leandro Pereira dos Santos

    2012-01-01

    Full Text Available The main objective of a production scheduling system is to assign tasks (orders or jobs to resources and sequence them as efficiently and economically (optimised as possible. Achieving this goal is a difficult task in complex environment where capacity is usually limited. In these scenarios, finding an optimal solution—if possible—demands a large amount of computer time. For this reason, in many cases, a good solution that is quickly found is preferred. In such situations, the use of metaheuristics is an appropriate strategy. In these last two decades, some out-of-the-shelf systems have been developed using such techniques. This paper presents and analyses the development of a shop-floor scheduling system that uses ant colony optimisation (ACO in a backward scheduling problem in a manufacturing scenario with single-stage processing, parallel resources, and flexible routings. This scenario was found in a large food industry where the corresponding author worked as consultant for more than a year. This work demonstrates the applicability of this artificial intelligence technique. In fact, ACO proved to be as efficient as branch-and-bound, however, executing much faster.

  18. Noise aspects at aerodynamic blade optimisation projects

    Energy Technology Data Exchange (ETDEWEB)

    Schepers, J.G. [Netherlands Energy Research Foundation, Petten (Netherlands)

    1997-12-31

    This paper shows an example of an aerodynamic blade optimisation, using the program PVOPT. PVOPT calculates the optimal wind turbine blade geometry such that the maximum energy yield is obtained. Using the aerodynamic optimal blade design as a basis, the possibilities of noise reduction are investigated. The aerodynamic optimised geometry from PVOPT is the `real` optimum (up to the latest decimal). The most important conclusion from this study is, that it is worthwhile to investigate the behaviour of the objective function (in the present case the energy yield) around the optimum: If the optimum is flat, there is a possibility to apply modifications to the optimum configuration with only a limited loss in energy yield. It is obvious that the modified configurations emits a different (and possibly lower) noise level. In the BLADOPT program (the successor of PVOPT) it will be possible to quantify the noise level and hence to assess the reduced noise emission more thoroughly. At present the most promising approaches for noise reduction are believed to be a reduction of the rotor speed (if at all possible), and a reduction of the tip angle by means of low lift profiles, or decreased twist at the outboard stations. These modifications were possible without a significant loss in energy yield. (LN)

  19. Multi-objective evolutionary optimisation for product design and manufacturing

    CERN Document Server

    2011-01-01

    Presents state-of-the-art research in the area of multi-objective evolutionary optimisation for integrated product design and manufacturing Provides a comprehensive review of the literature Gives in-depth descriptions of recently developed innovative and novel methodologies, algorithms and systems in the area of modelling, simulation and optimisation

  20. Optimisation of GnRH antagonist use in ART

    NARCIS (Netherlands)

    Hamdine, O.

    2014-01-01

    This thesis focuses on the optimisation of controlled ovarian stimulation for IVF using exogenous FSH and GnRH antagonist co-treatment, by studying the timing of the initiation of GnRH antagonist co-medication and the role of ovarian reserve markers in optimising ovarian response and reproductive ou

  1. Aerodynamic shape parameterisation and optimisation of novel configurations

    NARCIS (Netherlands)

    Straathof, M.H.; Van Tooren, M.J.L.; Voskuijl, M.; Koren, B.

    2008-01-01

    The Multi-Disciplinary Design Optimisation (MDO) process can be supported by partial automation of analysis and optimisation steps. Design and Engineering Engines (DEE) are useful concepts to structure this type of automation. Within the DEE, a product can be parameterically defined using Knowledge

  2. DACIA LOGAN LIVE AXLE OPTIMISATION USING COMPUTER GRAPHICS

    Directory of Open Access Journals (Sweden)

    KIRALY Andrei

    2017-05-01

    Full Text Available The paper presents some contributions to the calculus and optimisation of a live axle used at Dacia Logan using computer graphics software for creating the model and afterwards using FEA evaluation to determine the effectiveness of the optimisation. Thus using specialized computer software, a simulation is made and the results were compared to the measured real prototype.

  3. There, and Back Again Quantum Theory and Global Optimisation

    CERN Document Server

    Audenaert, K M R

    2004-01-01

    We consider a problem in quantum theory that can be formulated as an optimisation problem and present a global optimisation algorithm for solving it, the foundation of which relies in turn on a theorem from quantum theory. To wit, we consider the maximal output purity $\

  4. Kriging based robust optimisation algorithm for minimax problems in electromagnetics

    Directory of Open Access Journals (Sweden)

    Li Yinjiang

    2016-12-01

    Full Text Available The paper discusses some of the recent advances in kriging based worst-case design optimisation and proposes a new two-stage approach to solve practical problems. The efficiency of the infill points allocation is improved significantly by adding an extra layer of optimisation enhanced by a validation process.

  5. GAOS: Spatial optimisation of crop and nature within agricultural fields

    NARCIS (Netherlands)

    Bruin, de S.; Janssen, H.; Klompe, A.; Lerink, P.; Vanmeulebrouk, B.

    2010-01-01

    This paper proposes and demonstrates a spatial optimiser that allocates areas of inefficient machine manoeuvring to field margins thus improving the use of available space and supporting map-based Controlled Traffic Farming. A prototype web service (GAOS) allows farmers to optimise tracks within the

  6. Parameter Optimisation for the Behaviour of Elastic Models over Time

    DEFF Research Database (Denmark)

    Mosegaard, Jesper

    2004-01-01

    Optimisation of parameters for elastic models is essential for comparison or finding equivalent behaviour of elastic models when parameters cannot simply be transferred or converted. This is the case with a large range of commonly used elastic models. In this paper we present a general method...... that will optimise parameters based on the behaviour of the elastic models over time....

  7. Multi-criterion scantling optimisation of cruise ships

    OpenAIRE

    2010-01-01

    A numerical tool for the optimisation of the scantlings of a ship is extended by considering production cost, weight and moment of iner tia in the objective function. A multi-criteria optimisation of a passenger ship is conducted to illustrate the analysis process. Pareto frontiers are obtained and results are verified with Bureau Veritas rules.

  8. Modified cuckoo search: A new gradient free optimisation algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Walton, S., E-mail: 512465@swansea.ac.uk [College of Engineering, Swansea University, Swansea SA2 8PP, Wales (United Kingdom); Hassan, O.; Morgan, K.; Brown, M.R. [College of Engineering, Swansea University, Swansea SA2 8PP, Wales (United Kingdom)

    2011-09-15

    Highlights: > Modified cuckoo search (MCS) is a new gradient free optimisation algorithm. > MCS shows a high convergence rate, able to outperform other optimisers. > MCS is particularly strong at high dimension objective functions. > MCS performs well when applied to engineering problems. - Abstract: A new robust optimisation algorithm, which can be regarded as a modification of the recently developed cuckoo search, is presented. The modification involves the addition of information exchange between the top eggs, or the best solutions. Standard optimisation benchmarking functions are used to test the effects of these modifications and it is demonstrated that, in most cases, the modified cuckoo search performs as well as, or better than, the standard cuckoo search, a particle swarm optimiser, and a differential evolution strategy. In particular the modified cuckoo search shows a high convergence rate to the true global minimum even at high numbers of dimensions.

  9. Optimisation of a Crossdocking Distribution Centre Simulation Model

    CERN Document Server

    Adewunmi, Adrian

    2010-01-01

    This paper reports on continuing research into the modelling of an order picking process within a Crossdocking distribution centre using Simulation Optimisation. The aim of this project is to optimise a discrete event simulation model and to understand factors that affect finding its optimal performance. Our initial investigation revealed that the precision of the selected simulation output performance measure and the number of replications required for the evaluation of the optimisation objective function through simulation influences the ability of the optimisation technique. We experimented with Common Random Numbers, in order to improve the precision of our simulation output performance measure, and intended to use the number of replications utilised for this purpose as the initial number of replications for the optimisation of our Crossdocking distribution centre simulation model. Our results demonstrate that we can improve the precision of our selected simulation output performance measure value using C...

  10. Open Cut resource Optimisation as applied to coal

    Institute of Scientific and Technical Information of China (English)

    Martin L.Smith

    2007-01-01

    Pit optimisation is the earliest and most established application of its kind in the minerals industry,but this has been primarily driven by metal,not coal.Coal has the same financiaI drivers for resource optimisation as does the metalliferous industry,yet pit optimisation is not common practice.Why? The following discussion presents the basics of pit optimisation as they relate to coal and illustrates how a technology developed for massive deposits is not suitable for thin.multi-seam deposits where mine planning is often driven more by product quality than by value drivers such as Net Present Value.An alternative methodology is presented that takes advantage of the data structure of bedded deposits to optimise resource recovery in terms of a production schedule that meets constraints on coal quality.

  11. Preparation, characterisation and optimisation of lithium battery anodes consisting of silicon synthesised using Laser assisted Chemical Vapour Pyrolysis

    Science.gov (United States)

    Veliscek, Ziga; Perse, Lidija Slemenik; Dominko, Robert; Kelder, Erik; Gaberscek, Miran

    2015-01-01

    Suitability of silicon prepared using Laser assisted Chemical Vapour Pyrolysis (LaCVP) as a potential anode material in lithium batteries is systematically investigated. Its compositional, morphological, physical-chemical and electrochemical properties are compared to a current benchmark commercial silicon. Important differences in particle size and particle composition are found which, as shown, affect critically the rheological properties of the corresponding electrode slurries. In order to overcome the rheological problems of prepared nanosilicon, we introduce and optimise a spraying method instead of using the usual casting technique for slurry application. Interestingly, the optimised electrodes show similar electrochemical performance, regardless of the particle size or composition of nanosilicon. This unexpected result is explained by the unusually high resistance of electrochemical wiring in silicon-based electrodes (about 60 Ohm per 1 mg cm-2 of active material loading). Despite that, the optimised material still shows a capacity up to 1200 mA h g-1 at a relatively high loading of 1.6 mg cm-2 and after 20 cycles. On the other hand, by decreasing the loading to below ca. 0.9 mg cm-2 the wiring problems are effectively overcome and capacities close to theoretical values can be obtained.

  12. Optimisation of Ag loading and alumina characteristics to give sulphur-tolerant Ag/Al2O3 catalyst for H2-assisted NH3-SCR of NOx

    DEFF Research Database (Denmark)

    Fogel, Sebastian; Doronkin, Dmitry E.; Gabrielsson, Pär;

    2012-01-01

    A series of Ag/Al2O3 catalysts with different alumina precursors and different Ag loadings were tested for H2 assisted NH3-SCR of NO. The catalysts were characterised (BET, XRD, NH3-TPD, ICP-OES, TEM and UV–vis spectroscopy) and tested as fresh catalyst, during long-term cycling tests with SO2...

  13. ATLAS software configuration and build tool optimisation

    CERN Document Server

    Rybkin, G; The ATLAS collaboration

    2014-01-01

    ATLAS software code base is over 6 million lines organised in about 2000 packages. It makes use of some 100 external software packages, is developed by more than 400 developers and used by more than 2500 physicists from over 200 universities and laboratories in 6 continents. To meet the challenge of configuration and building of this software, the Configuration Management Tool (CMT) is used. CMT expects each package to describe its build targets, build and environment setup parameters, dependencies on other packages in a text file called requirements, and each project (group of packages) to describe its policies and dependencies on other projects in a text project file. Based on the effective set of configuration parameters read from the requirements files of dependent packages and project files, CMT commands build the packages, generate the environment for their use, or query the packages. The main focus was on build time performance that was optimised within several approaches: reduction of the number of re...

  14. ATLAS software configuration and build tool optimisation

    CERN Document Server

    Rybkin, G; The ATLAS collaboration

    2013-01-01

    ATLAS software code base is over 6 million lines organised in about 2000 packages. It makes use of some 100 external software packages, is developed by more than 400 developers and used by more than 2500 physicists from over 200 universities and laboratories in 6 continents. To meet the challenge of configuration and building of this software, the Configuration Management Tool (CMT) is used. CMT expects each package to describe its build targets, build and environment setup parameters, dependencies on other packages in a text file called requirements, and each project (group of packages) to describe its policies and dependencies on other projects in a text project file. Based on the effective set of configuration parameters read from the requirements files of dependent packages and project files, CMT commands build the packages, generate the environment for their use, or query the packages. The main focus was on build time performance that was optimised within several approaches: reduction of the number of re...

  15. Specification, Verification and Optimisation of Business Processes

    DEFF Research Database (Denmark)

    Herbert, Luke Thomas

    to model checking. This allows for a rich set of both qualitative and quantitative properties of a business process to be precisely determined in an automated fashion directly from the model of the business process. A number of advanced applications of this framework are presented which allow for automated...... Model and Notation (BPMN). The automated analysis of business processes is done by means of quantitative probabilistic model checking which allows verification of validation and performance properties through use of an algorithm for the translation of business process models into a format amenable......This thesis develops a unified framework wherein to specify, verify and optimise stochastic business processes. This framework provides for the modelling of business processes via a mathematical structure which captures business processes as a series of connected activities. This structure...

  16. FEM Optimisation of Spark Plasma Sintering Furnace

    CERN Document Server

    Kellari, Demetrios Vasili

    2013-01-01

    Coupled electro-thermal FEM analysis has been carried out on a sintering furnace used to produce new materials for LHC collimators. The analysis showed there exist margins for improvement of the current process and equipment through minor changes. To optimise the design of the furnace several design changes have been proposed including: optimization of material selection using copper cooling plates, control of convection in cooling plates by lowering the water flow rate, modifying the electrode shape using unsymmetrical electrodes and upgrading the thermal shielding to make use of multilayer graphite shields. The results show that we have a significant improvement in temperature gradient on the plate, from 453 to 258 °C and a reduction in power requirement from 62 to 44 kW.

  17. Niobium Cavity Electropolishing Modelling and Optimisation

    CERN Document Server

    Ferreira, L M A; Forel, S; Shirra, J A

    2013-01-01

    It’s widely accepted that electropolishing (EP) is the most suitable surface finishing process to achieve high performance bulk Nb accelerating cavities. At CERN and in preparation for the processing of the 704 MHz high-beta Superconducting Proton Linac (SPL) cavities a new vertical electropolishing facility has been assembled and a study is on-going for the modelling of electropolishing on cavities with COMSOL® software. In a first phase, the electrochemical parameters were taken into account for a fixed process temperature and flow rate, and are presented in this poster as well as the results obtained on a real SPL single cell cavity. The procedure to acquire the data used as input for the simulation is presented. The modelling procedure adopted to optimise the cathode geometry, aimed at a uniform current density distribution in the cavity cell for the minimum working potential and total current is explained. Some preliminary results on fluid dynamics is also briefly described.

  18. Improving and optimising road pricing in Copenhagen

    DEFF Research Database (Denmark)

    Nielsen, Otto Anker; Larsen, Marie Karen

    2008-01-01

    though quite a number of proposed charging systems have been examined only a few pricing strategies have been investigated. This paper deals with the optimisation of different designs for a road pricing system in the Greater Copenhagen area with respect to temporal and spatial differentiation......The question whether to introduce toll rings or road pricing in Copenhagen has been discussed intensively during the last 10 years. The main results of previous analyses are that none of the systems would make a positive contribution at present, when considered from a socio-economic view. Even...... of the pricing levels. A detailed transport model was used to describe the demand effects. The model was based on data from a real test of road pricing on 500 car drivers. The paper compares the price systems with regard to traffic effects and generalised costs for users and society. It is shown how important...

  19. A code for optimising triplet layout

    CERN Document Server

    Van Riesen-Haupt, Leon; Abelleira, Jose; Cruz Alaniz, Emilia

    2017-01-01

    One of the main challenges when designing final focus systems of particle accelerators is maximising the beam stay clear in the strong quadrupole magnets of the inner triplet. Moreover it is desirable to keep the quadrupoles in the inner triplet as short as possible for space and costs reasons but also to reduce chromaticity and simplify corrections schemes. An algorithm that explores the triplet parameter space to optimise both these aspects was written. It uses thin lenses as a first approximation for a broad parameter scan and MADX for more precise calculations. The thin lens algorithm is significantly faster than a full scan using MADX and relatively precise at indicating the approximate area where the optimum solution lies.

  20. Optimising Signalised Intersection Using Wireless Vehicle Detectors

    DEFF Research Database (Denmark)

    Adjin, Daniel Michael Okwabi; Torkudzor, Moses; Asare, Jack

    Traffic congestion on roads wastes travel times. In this paper, we developed a vehicular traffic model to optimise a signalised intersection in Accra, using wireless vehicle detectors. Traffic volume gathered was extrapolated to cover 2011 and 2016 and were analysed to obtain the peak hour traffic...... volume causing congestion. The intersection was modelled and simulated in Synchro7 as an actuated signalised model using results from the analysed data. The model for morning peak periods gave optimal cycle lengths of 100s and 150s with corresponding intersection delay of 48.9s and 90.6s in 2011 and 2016...... respectively while that for the evening was 55s giving delay of 14.2s and 16.3s respectively. It is shown that the model will improve traffic flow at the intersection....

  1. Optimisation of Multilayer Insulation an Engineering Approach

    CERN Document Server

    Chorowski, M; Parente, C; Riddone, G

    2001-01-01

    A mathematical model has been developed to describe the heat flux through multilayer insulation (MLI). The total heat flux between the layers is the result of three distinct heat transfer modes: radiation, residual gas conduction and solid spacer conduction. The model describes the MLI behaviour considering a layer-to-layer approach and is based on an electrical analogy, in which the three heat transfer modes are treated as parallel thermal impedances. The values of each of the transfer mode vary from layer to layer, although the total heat flux remains constant across the whole MLI blanket. The model enables the optimisation of the insulation with regard to different MLI parameters, such as residual gas pressure, number of layers and boundary temperatures. The model has been tested with experimental measurements carried out at CERN and the results revealed to be in a good agreement, especially for insulation vacuum between 10-5 Pa and 10-3 Pa.

  2. Common mode chokes and optimisation aspects

    Science.gov (United States)

    Kut, T.; Lücken, A.; Dickmann, S.; Schulz, D.

    2014-11-01

    Due to the increasing electrification of modern aircraft, as a result of the More Electric Aircraft concept, new strategies and approaches are required to fulfil the strict EMC aircraft standards (DO-160/ED-14-Sec. 20). Common mode chokes are a key component of electromagnetic filters and often oversized because of the unknown impedance of the surrounding power electronic system. This oversizing results in an increase of weight and volume. It has to be avoided as far as possible for mobile applications. In this context, an advanced method is presented to measure these impedances under operating conditions. Furthermore, the different parameters of the inductance design is explained and an optimisation for weight and volume is introduced.

  3. Differences in lumbar spine load due to posture and upper limb external load.

    Science.gov (United States)

    Kamińska, Joanna; Roman-Liu, Danuta; Zagrajek, Tomasz; Borkowski, Paweł

    2010-01-01

    As the lumbar region of the spine is particularly predisposed to musculoskeletal disorders, the aim of this article was to assess lumbar spine load on the basis of an accurate model of this part of the body. The model was developed with the finite element method and the energy criterion for optimising muscle work. Computer calculations confirmed that stresses and compression forces in intervertebral discs increased with an increase in the load force and that they were significantly larger in the bent forwards posture than in the erect posture. This result clearly shows that lifting light objects and the erect posture are important elements in minimising spine load.

  4. Studies towards optimisation of the analog hadronic calorimeter for future linear collider detectors

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Huong Lan [Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg (Germany); Collaboration: CALICE-D-Collaboration

    2016-07-01

    The Analog Hadronic Calorimeter (AHCAL) is a highly granular calorimeter developed in the CALICE collaboration for future linear collider detectors. Its design concept is based on 3 x 3 cm{sup 2} scintillator tiles readout by Silicon Photomultipliers (SiPM). With this design the ambitious required jet energy resolution of 3-4 % can be achieved using the Pandora Particle Flow Algorithm (PandoraPFA). Recent discussions concerning the overall size and cost of the ILD detector has triggered new studies to optimise AHCAL cell size. A smaller number of cells can reduce the detector cost but the corresponding larger cell size can lead to a degradation of the jet energy resolution. The AHCAL optimisation study therefore has to achieve the best balance between physics performance and cost. Recent studies using the latest version of PandoraPFA with improved pattern recognition have shown significant improvement of jet energy resolution. Moreover, a better energy reconstruction of single particles, in which software compensation plays an important role, can lead to further improvements. This talk will discuss the software compensation technique and its impact on the final cell size optimisation.

  5. The optimisation, design and verification of feed horn structures for future Cosmic Microwave Background missions

    Science.gov (United States)

    McCarthy, Darragh; Trappe, Neil; Murphy, J. Anthony; O'Sullivan, Créidhe; Gradziel, Marcin; Doherty, Stephen; Huggard, Peter G.; Polegro, Arturo; van der Vorst, Maarten

    2016-05-01

    In order to investigate the origins of the Universe, it is necessary to carry out full sky surveys of the temperature and polarisation of the Cosmic Microwave Background (CMB) radiation, the remnant of the Big Bang. Missions such as COBE and Planck have previously mapped the CMB temperature, however in order to further constrain evolutionary and inflationary models, it is necessary to measure the polarisation of the CMB with greater accuracy and sensitivity than before. Missions undertaking such observations require large arrays of feed horn antennas to feed the detector arrays. Corrugated horns provide the best performance, however owing to the large number required (circa 5000 in the case of the proposed COrE+ mission), such horns are prohibitive in terms of thermal, mechanical and cost limitations. In this paper we consider the optimisation of an alternative smooth-walled piecewise conical profiled horn, using the mode-matching technique alongside a genetic algorithm. The technique is optimised to return a suitable design using efficient modelling software and standard desktop computing power. A design is presented showing a directional beam pattern and low levels of return loss, cross-polar power and sidelobes, as required by future CMB missions. This design is manufactured and the measured results compared with simulation, showing excellent agreement and meeting the required performance criteria. The optimisation process described here is robust and can be applied to many other applications where specific performance characteristics are required, with the user simply defining the beam requirements.

  6. Starch/polyester films: simultaneous optimisation of the properties for the production of biodegradable plastic bags

    Directory of Open Access Journals (Sweden)

    J. B. Olivato

    2013-01-01

    Full Text Available Blends of starch/polyester have been of great interest in the development of biodegradable packaging. A method based on multiple responses optimisation (Desirability was used to evaluate the properties of tensile strength, perforation force, elongation and seal strength of cassava starch/poly(butylene adipate-co-terephthalate (PBAT blown films produced via a one-step reactive extrusion using tartaric acid (TA as a compatibiliser. Maximum results for all the properties were set as more desirable, with an optimal formulation being obtained which contained (55:45 starch/PBAT (88.2 wt. (%, glycerol (11.0 wt. (% and TA (0.8 wt. (%. Biodegradable plastic bags were produced using the film with this formulation, and analysed according to the standard method of the Associação Brasileira de Normas Técnicas (ABNT. The bags exhibited a 45% failure rate in free-falling dart impact tests, a 10% of failure rate in dynamic load tests and no failure in static load tests. These results meet the specifications set by the standard. Thus, the biodegradable plastic bags fabricated with an optimised formulation could be useful as an alternative to those made from non-biodegradable materials if the nominal capacity declared for this material is considered.

  7. Risk Assessment and Optimisation of Blast Mitigation Strategies for Design and Strengthening of Built Infrastructure

    Institute of Scientific and Technical Information of China (English)

    STEWART Mark G

    2006-01-01

    A probabilistic risk assessment procedure is developed which can predict risks of explosive blast damage to built infrastructure,and when combined with life-cycle cost analysis,the procedure can be used to optimise blastmitigation strategies.The paper focuses on window glazing since this is a load-capacity system which,when subjected to blast loading,has caused significant damage and injury to building occupants.Structural reliability techniques are used to derive blast reliability curves for annealed and toughened glazing subjected to explosive blast for a variety of threat scenarios.The probabilistic analyses include the uncertainties associated with blast modelling,glazing response and glazing failure criteria.Damage risks are calculated for an individual window and for windows in the facade of a multi-storey commercial building.The paper shows an illustrative exampie of how this information,when combined with risk-based decision-making criteria,can be used to optimise blast mitigation strategies.

  8. Load Measurements

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regarding...... the fatigue loads, the rotor, blades and tower moments are presented. The fatigue loads are evaluated using rainflow counting described in detail in Ref. [1]. The 1Hz equivalent load ranges are calculated at different wind speeds. All information regarding the instrumentation is collected in [ref 4] and [ref...

  9. Profile control studies for JET optimised shear regime

    Energy Technology Data Exchange (ETDEWEB)

    Litaudon, X.; Becoulet, A.; Eriksson, L.G.; Fuchs, V.; Huysmans, G.; How, J.; Moreau, D.; Rochard, F.; Tresset, G.; Zwingmann, W. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee, DRFC, 13 - Saint-Paul-lez-Durance (France); Bayetti, P.; Joffrin, E.; Maget, P.; Mayorat, M.L.; Mazon, D.; Sarazin, Y. [JET Abingdon, Oxfordshire (United Kingdom); Voitsekhovitch, I. [Universite de Provence, LPIIM, Aix-Marseille 1, 13 (France)

    2000-03-01

    This report summarises the profile control studies, i.e. preparation and analysis of JET Optimised Shear plasmas, carried out during the year 1999 within the framework of the Task-Agreement (RF/CEA/02) between JET and the Association Euratom-CEA/Cadarache. We report on our participation in the preparation of the JET Optimised Shear experiments together with their comprehensive analyses and the modelling. Emphasis is put on the various aspects of pressure profile control (core and edge pressure) together with detailed studies of current profile control by non-inductive means, in the prospects of achieving steady, high performance, Optimised Shear plasmas. (authors)

  10. Application of optimisation techniques in groundwater quantity and quality management

    Indian Academy of Sciences (India)

    Amlan Das; Bithin Datta

    2001-08-01

    This paper presents the state-of-the-art on application of optimisation techniques in groundwater quality and quantity management. In order to solve optimisation-based groundwater management models, researchers have used various mathematical programming techniques such as linear programming (LP), nonlinear programming (NLP), mixed-integer programming (MIP), optimal control theory-based mathematical programming, differential dynamic programming (DDP), stochastic programming (SP), combinatorial optimisation (CO), and multiple objective programming for multipurpose management. Studies reported in the literature on the application of these methods are reviewed in this paper.

  11. Genetic Algorithm Optimisation of a Ship Navigation System

    Directory of Open Access Journals (Sweden)

    E. Alfaro-Cid

    2001-01-01

    Full Text Available The optimisation of the PID controllers' gains for separate propulsion and heading control systems of CyberShip I, a scale model of an oil platform supply ship, using Genetic Algorithms is considered. During the initial design process both PID controllers have been manually tuned to improve their performance. However this tuning approach is a tedious and time consuming process. A solution to this problem is the use of optimisation techniques based on Genetic Algorithms to optimise the controllers' gain values. This investigation has been carried out through computer-generated simulations based on a non-linear hydrodynamic model of CyberShip I.

  12. Variable EBV DNA Load Distributions and Heterogeneous EBV mRNA Expression Patterns in the Circulation of Solid Organ versus Stem Cell Transplant Recipients

    NARCIS (Netherlands)

    Greijer, A. E.; Stevens, S. J.; Verkuijlen, S. A.; Juwana, H.; Fleig, S. C.; Verschuuren, E. A.; Hepkema, B. G.; Cornelissen, J. J.; Brooimans, R. A.; Verdonck, L. F.; Middeldorp, J. M.

    2012-01-01

    Epstein-Barr virus (EBV) driven post-transplant lymphoproliferative disease (PTLD) is a heterogeneous and potentially life-threatening condition. Early identification of aberrant EBV activity may prevent progression to B-cell lymphoma. We measured EBV DNA load and RNA profiles in plasma and cellular

  13. Variable EBV DNA load distributions and heterogeneous EBV mRNA expression patterns in the circulation of solid organ versus stem cell transplant recipients

    NARCIS (Netherlands)

    A.E. Greijer; S.J. Stevens; S.A. Verkuijlen; H. Juwana; S.C. Fleig; E.A. Verschuuren; B.G. Hepkema (Bouke); J.J. Cornelissen (Jan); R.A. Brooimans (Rik); L.F. Verdonck (Leo); J.M. Middeldorp (Jaap)

    2012-01-01

    textabstractEpstein-Barr virus (EBV) driven post-transplant lymphoproliferative disease (PTLD) is a heterogeneous and potentially life-threatening condition. Early identification of aberrant EBV activity may prevent progression to B-cell lymphoma. We measured EBV DNA load and RNA profiles in plasma

  14. Optimisation of sanitary landfill leachate treatment in a sequencing batch reactor.

    Science.gov (United States)

    Spagni, A; Marsili-Libelli, S; Lavagnolo, M C

    2008-01-01

    A bench-scale SBR was operated for almost three years in an attempt to optimise the treatment of leachates generated in old landfill. The results of the first two years were used to design a monitoring and control system based on artificial intelligence concepts. Nitrogen removal was optimized via the nitrite shortcut. Nitrification and N removal were usually higher than 98% and 90%, respectively, whereas COD (of the leachate) removal was approximately 30-40%. The monitoring and control system was demonstrated capable of optimizing process operation, in terms of phase length and external COD addition, to the varying loading conditions. Using the control system developed, a significant improvement of the process was obtained: COD and N load were increased (HRT decrease) and a significant decrease (approximately 34%) of the ratio of COD added to N leachate content was observed.

  15. Use of Numerical Simulation at Optimisation of Technological Processes of Cold Bulk Forming

    Directory of Open Access Journals (Sweden)

    Stanislav RUSZ

    2012-06-01

    Full Text Available The paper deals with numerical and physical modelling aimed at optimisation of production technology and designing of manufacturing tools with use of finite-element method. For the topic of cold bulk forming a manufacture of pressed insert, used in industry as a component for damping system for passenger cars, was simulated. It is a rotationally symmetric component, which is subjected to high axial load, and strength and fatigue characteristics of which depend substantially on service life and reliability of the whole damping system. This component was subjected to analysis of distribution of flow stress and deformation intensity at combined extrusion from the viewpoint of their load with use of simulating software Simufact.Forming 10.0. The simulation process ran smoothly, without sudden changes of the shape leading to formation of possible internal defects.

  16. Design optimisation of a flywheel hybrid vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Kok, D.B.

    1999-11-04

    This thesis describes the design optimisation of a flywheel hybrid vehicle with respect to fuel consumption and exhaust gas emissions. The driveline of this passenger car uses two power sources: a small spark ignition internal combustion engine with three-way catalyst, and a highspeed flywheel system for kinetic energy storage. A custom-made continuously variable transmission (CVT) with so-called i{sup 2} control transports energy between these power sources and the vehicle wheels. The driveline includes auxiliary systems for hydraulic, vacuum and electric purposes. In this fully mechanical driveline, parasitic energy losses determine the vehicle's fuel saving potential to a large extent. Practicable energy loss models have been derived to quantify friction losses in bearings, gearwheels, the CVT, clutches and dynamic seals. In addition, the aerodynamic drag in the flywheel system and power consumption of auxiliaries are charted. With the energy loss models available, a calculation procedure is introduced to optimise the flywheel as a subsystem in which the rotor geometry, the safety containment, and the vacuum system are designed for minimum energy use within the context of automotive applications. A first prototype of the flywheel system was tested experimentally and subsequently redesigned to improve rotordynamics and safety aspects. Coast-down experiments with the improved version show that the energy losses have been lowered significantly. The use of a kinetic energy storage device enables the uncoupling of vehicle wheel power and engine power. Therefore, the engine can be smaller and it can be chosen to operate in its region of best efficiency in start-stop mode. On a test-rig, the measured engine fuel consumption was reduced with more than 30 percent when the engine is intermittently restarted with the aid of the flywheel system. Although the start-stop mode proves to be advantageous for fuel consumption, exhaust gas emissions increase temporarily

  17. Optimised Hybrid Integrated Renewable Energy System

    Directory of Open Access Journals (Sweden)

    Dr. Arun Sandilya

    2012-10-01

    Full Text Available A hybrid integrated renewable energy system for an isolated small community, where grid extension is considered uneconomical. This paper proposed cost optimization through dynamic matching between load and proper equipment sizing. The Matlab based computer program developed for determining the most cost effective energy source to supply required load any given time of the day. Integrated system based on green energy utilization and rural electricity development.

  18. Load Measurements

    DEFF Research Database (Denmark)

    Vesth, Allan; Kock, Carsten Weber

    The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regardi...

  19. Load Measurements

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regarding...

  20. Operational optimisation of water supply networks using a fuzzy ...

    African Journals Online (AJOL)

    Operational optimisation of water supply networks using a fuzzy system. ... This paper presents a fuzzy system to control the pressure in a water distribution network, by using valves and controlling the rotor speed of the ... Article Metrics.

  1. Exploring RSSI Dependency on Height in UHF for throughput optimisation

    CSIR Research Space (South Africa)

    Maliwatu, R

    2016-11-01

    Full Text Available International Conference on Advances in Computing & Communication Engineering (ICACCE), 28-29 November 2016, Durban, South Africa Exploring RSSI Dependency on Height in UHF for throughput optimisation Richard Maliwatu Albert Lysko David Johnson...

  2. Share-of-Surplus Product Line Optimisation with Price Levels

    Directory of Open Access Journals (Sweden)

    X. G. Luo

    2014-01-01

    Full Text Available Kraus and Yano (2003 established the share-of-surplus product line optimisation model and developed a heuristic procedure for this nonlinear mixed-integer optimisation model. In their model, price of a product is defined as a continuous decision variable. However, because product line optimisation is a planning process in the early stage of product development, pricing decisions usually are not very precise. In this research, a nonlinear integer programming share-of-surplus product line optimization model that allows the selection of candidate price levels for products is established. The model is further transformed into an equivalent linear mixed-integer optimisation model by applying linearisation techniques. Experimental results in different market scenarios show that the computation time of the transformed model is much less than that of the original model.

  3. Open Pit Optimisation and Design: A Stepwise Approach*

    African Journals Online (AJOL)

    Michael

    2015-12-02

    Dec 2, 2015 ... holes were used for the analysis. ... retrieval and analysis, using Surpac software. .... economic and technical parameters were used to produce a set of nested pits. Fig. 4 depicts a summarised flow chart for the pit optimisation.

  4. Optimisation of patient protection and image quality in diagnostic ...

    African Journals Online (AJOL)

    Optimisation of patient protection and image quality in diagnostic radiology. ... The study leads to the introduction of the concept of plan- do-check-act on QC results ... (QA) programme and continues to collect data for establishment of DRL's.

  5. A Comparison of Existing Optimisation Techniques with the ...

    African Journals Online (AJOL)

    ... Existing Optimisation Techniques with the Univariate Marginal Distribution Algorithm ... graph colouring, neural networks, genetic algorithms and tabu search. ... optimization techniques and we show how the proposed algorithm performs in ...

  6. Elliptical Antenna Array Synthesis Using Backtracking Search Optimisation Algorithm

    Directory of Open Access Journals (Sweden)

    Kerim Guney

    2016-04-01

    Full Text Available The design of the elliptical antenna arrays is relatively new research area in the antenna array community. Backtracking search optimisation algorithm (BSA is employed for the synthesis of elliptical antenna arrays having different number of array elements. For this aim, BSA is used to calculate the optimum angular position and amplitude values of the array elements. BSA is a population-based iterative evolutionary algorithm. The remarkable properties of BSA are that it has a good optimisation performance, simple implementation structure, and few control parameters. The results of BSA are compared with those of self-adaptive differential evolution algorithm, firefly algorithm, biogeography based optimisation algorithm, and genetic algorithm. The results show that BSA can reach better solutions than the compared optimisation algorithms. Iterative performances of BSA are also compared with those of bacterial foraging algorithm and differential search algorithm.

  7. Construction and optimisation of a cartridge filter for removing ...

    African Journals Online (AJOL)

    Construction and optimisation of a cartridge filter for removing fluoride in drinking water. ... It was found that the optimal conditions for the F- filter that gave the best results in removing of F- from water with minimum ... Article Metrics.

  8. Weight Optimisation of Steel Monopile Foundations for Offshore Windfarms

    DEFF Research Database (Denmark)

    Fog Gjersøe, Nils; Bouvin Pedersen, Erik; Kristensen, Brian;

    2015-01-01

    The potential for mass reduction of monopiles in offshore windfarms using current design practice is investigated. Optimisation by sensitivity analysis is carried out for the following important parameters: wall thickness distribution between tower and monopile, soil stiffness, damping ratio and ...

  9. Changes in distributional patterns of plaice Pleuronectes platessa in the central and eastern North Sea; do declining nutrient loadings play a role?

    DEFF Research Database (Denmark)

    Støttrup, Josianne Gatt; Munk, Peter; Kodama, Masashi

    2017-01-01

    . For the same time period available time series data on nutrient conditions in the coastalNorth Sea area showthat the freshwater nitrogen loading has decreased by about 50%. While nutrient concentrations in the ambient environment have been shown to influence growth in juvenile plaice through influence...... sandbank in a shallowoffshore area of the North Sea. The Dogger Bank, was used as a reference location assuming this area has been less influenced from coastal eutrophication but similar regional climate conditions, and here we found no changes in the abundances of juvenile plaice. The increase in the use...... of offshore habitats as nursery areas by juvenile plaice in the North Sea appears not related to water depth per se but driven by specific processes dominating in near-shore areas and may be related to changes in nutrient loadings. This point to the importance of separating more general depth-related factors...

  10. Biomolecular Cell-Signaling Mechanisms and Dental Implants: A Review on the Regulatory Molecular Biologic Patterns Under Functional and Immediate Loading.

    Science.gov (United States)

    Romanos, Georgios E

    2016-01-01

    Bone tissue adapts its structure and mass to the stresses of mechanical loading. The purpose of this review article was to summarize recent advances on cell signaling relating to the phenomenon of bone remodeling, focused on bone ossification and healing at the interface of dental implants and bone under loading conditions. When a dental implant is placed within an osteotomy, osteocytes, osteoblasts, and osteoclasts are all present. As functional loads are imposed, the remodeling processes adapt the peri-implant bony tissues to mechanical stimuli over time and reestablish a steady state. Based on the current literature, this article demonstrates fundamental information to these remodeling processes, such as the conversion of mechanical cues to electrical or biochemical signals. Multiple intracellular signals are involved in cellular mechanotransduction; the two Wnt signaling pathways (the canonical, β-catenin-dependent and the noncanonical, β-catenin-independent Wnt pathway) are particularly significant. Knowledge of how these molecular signaling pathways are translated into intracellular signals that regulate cell behavior may provide new therapeutic approaches to enhancing osteogenesis, especially around implants with immediate function or placed in areas of poor bone quality. New knowledge about the primary cilia as an organelle and bone cellular mechanosensor is critical for endochondral ossification and proper signal transduction. Other mechanisms, such as the expression of sclerostin as a negative regulator of bone formation (due to deactivation of the Wnt receptor) and downregulation of sclerostin under loading conditions, also present new understanding of the cellular and pericellular mechanics of bone. The complexity of the cell signaling pathways and the mechanisms involved in the mechanoregulation of the bone formation provide new technologies and perspectives for mechanically induced cellular response. Future novel therapeutic approaches based on the

  11. Variable EBV DNA Load Distributions and Heterogeneous EBV mRNA Expression Patterns in the Circulation of Solid Organ versus Stem Cell Transplant Recipients

    Directory of Open Access Journals (Sweden)

    A. E. Greijer

    2012-01-01

    Full Text Available Epstein-Barr virus (EBV driven post-transplant lymphoproliferative disease (PTLD is a heterogeneous and potentially life-threatening condition. Early identification of aberrant EBV activity may prevent progression to B-cell lymphoma. We measured EBV DNA load and RNA profiles in plasma and cellular blood compartments of stem cell transplant (SCT; n=5, solid organ transplant recipients (SOT; n=15, and SOT having chronic elevated EBV-DNA load (n=12. In SCT, EBV DNA was heterogeneously distributed, either in plasma or leukocytes or both. In SOT, EBV DNA load was always cell associated, predominantly in B cells, but occasionally in T cells (CD4 and CD8 or monocytes. All SCT with cell-associated EBV DNA showed BARTs and EBNA1 expression, while LMP1 and LMP2 mRNA was found in 1 and 3 cases, respectively. In SOT, expression of BARTs was detected in all leukocyte samples. LMP2 and EBNA1 mRNA was found in 5/15 and 2/15, respectively, but LMP1 mRNA in only 1, coinciding with severe PTLD and high EBV DNA. Conclusion: EBV DNA is differently distributed between white cells and plasma in SOT versus SCT. EBV RNA profiling in blood is feasible and may have added value for understanding pathogenic virus activity in patients with elevated EBV-DNA.

  12. optPBN: An Optimisation Toolbox for Probabilistic Boolean Networks

    Science.gov (United States)

    Trairatphisan, Panuwat; Mizera, Andrzej; Pang, Jun; Tantar, Alexandru Adrian; Sauter, Thomas

    2014-01-01

    Background There exist several computational tools which allow for the optimisation and inference of biological networks using a Boolean formalism. Nevertheless, the results from such tools yield only limited quantitative insights into the complexity of biological systems because of the inherited qualitative nature of Boolean networks. Results We introduce optPBN, a Matlab-based toolbox for the optimisation of probabilistic Boolean networks (PBN) which operates under the framework of the BN/PBN toolbox. optPBN offers an easy generation of probabilistic Boolean networks from rule-based Boolean model specification and it allows for flexible measurement data integration from multiple experiments. Subsequently, optPBN generates integrated optimisation problems which can be solved by various optimisers. In term of functionalities, optPBN allows for the construction of a probabilistic Boolean network from a given set of potential constitutive Boolean networks by optimising the selection probabilities for these networks so that the resulting PBN fits experimental data. Furthermore, the optPBN pipeline can also be operated on large-scale computational platforms to solve complex optimisation problems. Apart from exemplary case studies which we correctly inferred the original network, we also successfully applied optPBN to study a large-scale Boolean model of apoptosis where it allows identifying the inverse correlation between UVB irradiation, NFκB and Caspase 3 activations, and apoptosis in primary hepatocytes quantitatively. Also, the results from optPBN help elucidating the relevancy of crosstalk interactions in the apoptotic network. Summary The optPBN toolbox provides a simple yet comprehensive pipeline for integrated optimisation problem generation in the PBN formalism that can readily be solved by various optimisers on local or grid-based computational platforms. optPBN can be further applied to various biological studies such as the inference of gene regulatory

  13. A supportive architecture for CFD-based design optimisation

    Science.gov (United States)

    Li, Ni; Su, Zeya; Bi, Zhuming; Tian, Chao; Ren, Zhiming; Gong, Guanghong

    2014-03-01

    Multi-disciplinary design optimisation (MDO) is one of critical methodologies to the implementation of enterprise systems (ES). MDO requiring the analysis of fluid dynamics raises a special challenge due to its extremely intensive computation. The rapid development of computational fluid dynamic (CFD) technique has caused a rise of its applications in various fields. Especially for the exterior designs of vehicles, CFD has become one of the three main design tools comparable to analytical approaches and wind tunnel experiments. CFD-based design optimisation is an effective way to achieve the desired performance under the given constraints. However, due to the complexity of CFD, integrating with CFD analysis in an intelligent optimisation algorithm is not straightforward. It is a challenge to solve a CFD-based design problem, which is usually with high dimensions, and multiple objectives and constraints. It is desirable to have an integrated architecture for CFD-based design optimisation. However, our review on existing works has found that very few researchers have studied on the assistive tools to facilitate CFD-based design optimisation. In the paper, a multi-layer architecture and a general procedure are proposed to integrate different CFD toolsets with intelligent optimisation algorithms, parallel computing technique and other techniques for efficient computation. In the proposed architecture, the integration is performed either at the code level or data level to fully utilise the capabilities of different assistive tools. Two intelligent algorithms are developed and embedded with parallel computing. These algorithms, together with the supportive architecture, lay a solid foundation for various applications of CFD-based design optimisation. To illustrate the effectiveness of the proposed architecture and algorithms, the case studies on aerodynamic shape design of a hypersonic cruising vehicle are provided, and the result has shown that the proposed architecture

  14. Multiobjective optimisation of bogie suspension to boost speed on curves

    Science.gov (United States)

    Milad Mousavi-Bideleh, Seyed; Berbyuk, Viktor

    2016-01-01

    To improve safety and maximum admissible speed on different operational scenarios, multiobjective optimisation of bogie suspension components of a one-car railway vehicle model is considered. The vehicle model has 50 degrees of freedom and is developed in multibody dynamics software SIMPACK. Track shift force, running stability, and risk of derailment are selected as safety objective functions. The improved maximum admissible speeds of the vehicle on curves are determined based on the track plane accelerations up to 1.5 m/s2. To attenuate the number of design parameters for optimisation and improve the computational efficiency, a global sensitivity analysis is accomplished using the multiplicative dimensional reduction method (M-DRM). A multistep optimisation routine based on genetic algorithm (GA) and MATLAB/SIMPACK co-simulation is executed at three levels. The bogie conventional secondary and primary suspension components are chosen as the design parameters in the first two steps, respectively. In the last step semi-active suspension is in focus. The input electrical current to magnetorheological yaw dampers is optimised to guarantee an appropriate safety level. Semi-active controllers are also applied and the respective effects on bogie dynamics are explored. The safety Pareto optimised results are compared with those associated with in-service values. The global sensitivity analysis and multistep approach significantly reduced the number of design parameters and improved the computational efficiency of the optimisation. Furthermore, using the optimised values of design parameters give the possibility to run the vehicle up to 13% faster on curves while a satisfactory safety level is guaranteed. The results obtained can be used in Pareto optimisation and active bogie suspension design problems.

  15. Optimisation as a process for understanding and managing river ecosystems

    OpenAIRE

    Barbour, EJ; Holz, L; G. Kuczera; Pollino, CA; Jakeman, AJ; Loucks, DP

    2016-01-01

    Optimisation can assist in the management of riverine ecosystems through the exploration of multiple alternative management strategies, and the evaluation of trade-offs between conflicting objectives. In addition, it can facilitate communication and learning about the system. However, the effectiveness of optimisation in aiding decision making for ecological management is currently limited by four major challenges: identification and quantification of ecosystem objectives; representation of e...

  16. Optimisation of the Sekwa blended-wing-Body research UAV

    CSIR Research Space (South Africa)

    Broughton, BA

    2008-10-01

    Full Text Available candidate design to bring the total mass up to the target total mass of 3.2 kg. The location of the ballast mass could be adjusted by the design code, which allowed the static margin to be used as a design variable. Finally, a series of checks were.... Overview of optimisation process OPTIMISER Genetic Algorithms + Gradient Based Methods Natural FQ constraints Geometric constraints Control system constraints Stall behaviour Design with best cruise performance Design parameters Generate...

  17. Aerodynamic optimisation of an industrial axial fan blade

    OpenAIRE

    2006-01-01

    Numerical optimisation methods have successfully been used for a variety of aerodynamic design problems over quite a few years. However the application of these methods to the aerodynamic blade shape optimisation of industrial axial fans has received much less attention in the literature probably given the fact that the majority of resources available to develop these automated design approaches is to be found in the aerospace field. This work presents the develo...

  18. Spreadsheets In Function Of Optimisation Of Logistics Network

    OpenAIRE

    Drago Pupavac; Mimo Draskovic

    2007-01-01

    This scientific paper discusses how estimated spreadsheets functions in logistics networks optimisation. The suggested working hypothesis for efficacy of estimated spreadsheets in designing logistics networks is proved and a practical example. In this way the given model can be applied to all logistics networks of similar problem capacity. Logistics network model confronting estimated spreadsheets present a real world at a level needed for understanding the problem of optimisation of logistic...

  19. Optimisation study of a vehicle bumper subsystem with fuzzy parameters

    Science.gov (United States)

    Farkas, L.; Moens, D.; Donders, S.; Vandepitte, D.

    2012-10-01

    This paper deals with the design and optimisation for crashworthiness of a vehicle bumper subsystem, which is a key scenario for vehicle component design. The automotive manufacturers and suppliers have to find optimal design solutions for such subsystems that comply with the conflicting requirements of the regulatory bodies regarding functional performance (safety and repairability) and regarding the environmental impact (mass). For the bumper design challenge, an integrated methodology for multi-attribute design engineering of mechanical structures is set up. The integrated process captures the various tasks that are usually performed manually, this way facilitating the automated design iterations for optimisation. Subsequently, an optimisation process is applied that takes the effect of parametric uncertainties into account, such that the system level of failure possibility is acceptable. This optimisation process is referred to as possibility-based design optimisation and integrates the fuzzy FE analysis applied for the uncertainty treatment in crash simulations. This process is the counterpart of the reliability-based design optimisation used in a probabilistic context with statistically defined parameters (variabilities).

  20. Optimised control of coal-fired boilers

    Energy Technology Data Exchange (ETDEWEB)

    Owens, D.H.; MacConnell, P.F.A.; Neuffer, D.; Dando, R. [University of Exeter, Exeter (United Kingdom). Centre for System and Control Engineering

    1997-07-01

    The objective of the project is to develop and specify a control methodology that will enable existing coal combustion plant to take maximum advantage of modern control techniques. The research is specifically aimed at chain-grate stoker plant (such as the test facility at the Coal Research Establishment, Cheltenham) on which little work has been done for thirty years yet which still represents a large proportion of industrial coal-fired plant in operation worldwide. In detail, the project: reviewed existing control strategies for moving grate stokers, highlighting their limitations and areas for improvements; carried out plant trials to identify the system characteristics such as response time and input/output behaviour; developed a theoretical process based on physical and chemical laws and backed up by trial data; specified control strategies for a single boiler; simulated and evaluated the control strategies using model simulations; developed of an optimised. Control strategy for a single boiler; and assessed the applicability and effects of this control strategy on multiple boiler installations. 67 refs., 34 figs.

  1. Semantic Query Optimisation with Ontology Simulation

    CERN Document Server

    Gupta, Siddharth

    2010-01-01

    Semantic Web is, without a doubt, gaining momentum in both industry and academia. The word "Semantic" refers to "meaning" - a semantic web is a web of meaning. In this fast changing and result oriented practical world, gone are the days where an individual had to struggle for finding information on the Internet where knowledge management was the major issue. The semantic web has a vision of linking, integrating and analysing data from various data sources and forming a new information stream, hence a web of databases connected with each other and machines interacting with other machines to yield results which are user oriented and accurate. With the emergence of Semantic Web framework the na\\"ive approach of searching information on the syntactic web is clich\\'e. This paper proposes an optimised semantic searching of keywords exemplified by simulation an ontology of Indian universities with a proposed algorithm which ramifies the effective semantic retrieval of information which is easy to access and time sav...

  2. ENERGY OPTIMISATION SCHEMES FOR WIRELESS SENSOR NETWORK

    Directory of Open Access Journals (Sweden)

    Vivekanand Jha

    2012-05-01

    Full Text Available A sensor network is composed of a large number of sensor nodes, which are densely deployed either inside the phenomenon or very close to it. Sensor nodes have sensing, processing and transmitting capability . They however have limited energy and measures need to be taken to make op- timum usage of their energy and save them from task of only receiving and transmitting data without processing. Various techniques for energy utilization optimisation have been proposed Ma jor players are however clustering and relay node placement. In the research related to relay node placement, it has been proposed to deploy some relay nodes such that the sensors can transmit the sensed data to a nearby relay node, which in turn delivers the data to the base stations. In general, the relay node placement problems aim to meet certain connectivity and/or survivabil- ity requirements of the network by deploying a minimum number of relay nodes. The other approach is grouping sensor nodes into clusters with each cluster having a cluster head (CH. The CH nodes aggregate the data and transmit them to the base station (BS. These two approaches has been widely adopted by the research community to satisfy the scala- bility objective and generally achieve high energy efficiency and prolong network lifetime in large-scale WSN environments and hence are discussed here along with single hop and multi hop characteristic of sensor node.

  3. Topological optimisation of rod-stirring devices

    CERN Document Server

    Finn, Matthew D

    2011-01-01

    There are many industrial situations where rods are used to stir a fluid, or where rods repeatedly stretch a material such as bread dough or taffy. The goal in these applications is to stretch either material lines (in a fluid) or the material itself (for dough or taffy) as rapidly as possible. The growth rate of material lines is conveniently given by the topological entropy of the rod motion. We discuss the problem of optimising such rod devices from a topological viewpoint. We express rod motions in terms of generators of the braid group, and assign a cost based on the minimum number of generators needed to write the braid. We show that for one cost function -- the topological entropy per generator -- the optimal growth rate is the logarithm of the golden ratio. For a more realistic cost function,involving the topological entropy per operation where rods are allowed to move together, the optimal growth rate is the logarithm of the silver ratio, $1+\\sqrt{2}$. We show how to construct devices that realise th...

  4. Optimising preterm nutrition: present and future

    LENUS (Irish Health Repository)

    Brennan, Ann-Marie

    2016-04-01

    The goal of preterm nutrition in achieving growth and body composition approximating that of the fetus of the same postmenstrual age is difficult to achieve. Current nutrition recommendations depend largely on expert opinion, due to lack of evidence, and are primarily birth weight based, with no consideration given to gestational age and\\/or need for catch-up growth. Assessment of growth is based predominately on anthropometry, which gives insufficient attention to the quality of growth. The present paper provides a review of the current literature on the nutritional management and assessment of growth in preterm infants. It explores several approaches that may be required to optimise nutrient intakes in preterm infants, such as personalising nutritional support, collection of nutrient intake data in real-time, and measurement of body composition. In clinical practice, the response to inappropriate nutrient intakes is delayed as the effects of under- or overnutrition are not immediate, and there is limited nutritional feedback at the cot-side. The accurate and non-invasive measurement of infant body composition, assessed by means of air displacement plethysmography, has been shown to be useful in assessing quality of growth. The development and implementation of personalised, responsive nutritional management of preterm infants, utilising real-time nutrient intake data collection, with ongoing nutritional assessments that include measurement of body composition is required to help meet the individual needs of preterm infants.

  5. Optimisation of the formulation of a bubble bath by a chemometric approach market segmentation and optimisation.

    Science.gov (United States)

    Marengo, Emilio; Robotti, Elisa; Gennaro, Maria Carla; Bertetto, Mariella

    2003-03-01

    The optimisation of the formulation of a commercial bubble bath was performed by chemometric analysis of Panel Tests results. A first Panel Test was performed to choose the best essence, among four proposed to the consumers; the best essence chosen was used in the revised commercial bubble bath. Afterwards, the effect of changing the amount of four components (the amount of primary surfactant, the essence, the hydratant and the colouring agent) of the bubble bath was studied by a fractional factorial design. The segmentation of the bubble bath market was performed by a second Panel Test, in which the consumers were requested to evaluate the samples coming from the experimental design. The results were then treated by Principal Component Analysis. The market had two segments: people preferring a product with a rich formulation and people preferring a poor product. The final target, i.e. the optimisation of the formulation for each segment, was obtained by the calculation of regression models relating the subjective evaluations given by the Panel and the compositions of the samples. The regression models allowed to identify the best formulations for the two segments ofthe market.

  6. Method for optimising the energy of pumps

    NARCIS (Netherlands)

    Skovmose Kallesøe, Carsten; De Persis, Claudio

    2011-01-01

    The method involves determining whether pumps (pu1, pu5) are directly assigned to loads (v1, v3) as pilot pumps (pu2, pu3) and hydraulically connected upstream of the pilot pumps. The upstream pumps are controlled with variable speed for energy optimization. Energy optimization circuits are selected

  7. Generation of Domestic Hot Water, Space Heating and Driving Pattern Profiles for Integration Analysis of Active Loads in Low Voltage Grids

    DEFF Research Database (Denmark)

    Diaz de Cerio Mendaza, Iker; Pigazo, Alberto; Bak-Jensen, Birgitte

    2013-01-01

    demand and electric vehicle driving profiles, to be used for power grid calculations. The generated thermal profiles relied on a statistical analysis made from real domestic hot water and space heating data from 25 households of a typical Danish residential area. The driving profiles instead were formed......The changes in the Danish energy sector, consequence of political agreements, are expected to have direct impact in the actual power distribution systems. Large number of electric boiler, heat pumps and electric vehicles are planned and will cope large percentage of the future power consumption...... at household level. Despite of the well-known flexible service that this kind of loads can provide, their flexibility is highly dependent of the domestic hot water and space heating demand and the driving habits of each user. This paper presents two methodologies employed to randomly generate thermal power...

  8. Protein Considerations for Optimising Skeletal Muscle Mass in Healthy Young and Older Adults

    Directory of Open Access Journals (Sweden)

    Oliver C. Witard

    2016-03-01

    Full Text Available Skeletal muscle is critical for human health. Protein feeding, alongside resistance exercise, is a potent stimulus for muscle protein synthesis (MPS and is a key factor that regulates skeletal muscle mass (SMM. The main purpose of this narrative review was to evaluate the latest evidence for optimising the amino acid or protein source, dose, timing, pattern and macronutrient coingestion for increasing or preserving SMM in healthy young and healthy older adults. We used a systematic search strategy of PubMed and Web of Science to retrieve all articles related to this review objective. In summary, our findings support the notion that protein guidelines for increasing or preserving SMM are more complex than simply recommending a total daily amount of protein. Instead, multifactorial interactions between protein source, dose, timing, pattern and macronutrient coingestion, alongside exercise, influence the stimulation of MPS, and thus should be considered in the context of protein recommendations for regulating SMM. To conclude, on the basis of currently available scientific literature, protein recommendations for optimising SMM should be tailored to the population or context of interest, with consideration given to age and resting/post resistance exercise conditions.

  9. Algorithme intelligent d'optimisation d'un design structurel de grande envergure

    Science.gov (United States)

    Dominique, Stephane

    genetic algorithm that prevents new individuals to be born too close to previously evaluated solutions. The restricted area becomes smaller or larger during the optimisation to allow global or local search when necessary. Also, a new search operator named Substitution Operator is incorporated in GATE. This operator allows an ANN surrogate model to guide the algorithm toward the most promising areas of the design space. The suggested CBR approach and GATE were tested on several simple test problems, as well as on the industrial problem of designing a gas turbine engine rotor's disc. These results are compared to other results obtained for the same problems by many other popular optimisation algorithms, such as (depending of the problem) gradient algorithms, binary genetic algorithm, real number genetic algorithm, genetic algorithm using multiple parents crossovers, differential evolution genetic algorithm, Hookes & Jeeves generalized pattern search method and POINTER from the software I-SIGHT 3.5. Results show that GATE is quite competitive, giving the best results for 5 of the 6 constrained optimisation problem. GATE also provided the best results of all on problem produced by a Maximum Set Gaussian landscape generator. Finally, GATE provided a disc 4.3% lighter than the best other tested algorithm (POINTER) for the gas turbine engine rotor's disc problem. One drawback of GATE is a lesser efficiency for highly multimodal unconstrained problems, for which he gave quite poor results with respect to its implementation cost. To conclude, according to the preliminary results obtained during this thesis, the suggested CBR process, combined with GATE, seems to be a very good candidate to automate and accelerate the structural design of mechanical devices, potentially reducing significantly the cost of industrial preliminary design processes.

  10. Optimisation of Ionic Models to Fit Tissue Action Potentials: Application to 3D Atrial Modelling

    Directory of Open Access Journals (Sweden)

    Amr Al Abed

    2013-01-01

    Full Text Available A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN, intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.

  11. OPTIMISATION OF RESIDENTIAL ROOF INSULATION LAYER THICKNESS BASED ON ECONOMIC ANALYSIS BY GREY RELATION METHOD

    Directory of Open Access Journals (Sweden)

    D. PRAKASH

    2015-12-01

    Full Text Available This study is focussed on the optimisation of residential building roof insulation layers that includes weathering tile, wood wool and phase change material through grey relation analysis and numerical simulation techniques. The optimum thickness of insulation layers is determined for the quality objective of minimization of insulation material cost and energy consumption cost by air conditioning system over a life time of 10 years. For optimisation of roof insulation layer, the insulation layers are varied to five levels with reference to the height of concrete (HC layer and various combination of roof layers are obtained from Taguchi’s L25 orthogonal array. The 25 combination of roof structures are analysed by Numerical simulation technique to determine yearly heating transmission load and in turn used to calculate the cost of energy consumption for cooling a period of 10 years. As a result, the optimum thickness value of roof insulation layer - weathering tile, wood wool and phase change material are predicted as 0.33*HC, 0.33*HC and 0.066*HC respectively and this optimum value will have the cost of insulation and yearly electricity cost of cooling for 10 years as 92 $/m2 and 12.45$/m2 respectively.

  12. Optimisation of composite metallic fuel for minor actinide transmutation in an accelerator-driven system

    Science.gov (United States)

    Uyttenhove, W.; Sobolev, V.; Maschek, W.

    2011-09-01

    A potential option for neutralization of minor actinides (MA) accumulated in spent nuclear fuel of light water reactors (LWRs) is their transmutation in dedicated accelerator-driven systems (ADS). A promising fuel candidate dedicated to MA transmutation is a CERMET composite with Mo metal matrix and (Pu, Np, Am, Cm)O 2-x fuel particles. Results of optimisation studies of the CERMET fuel targeting to increasing the MA transmutation efficiency of the EFIT (European Facility for Industrial Transmutation) core are presented. In the adopted strategy of MA burning the plutonium (Pu) balance of the core is minimized, allowing a reduction in the reactivity swing and the peak power form-factor deviation and an extension of the cycle duration. The MA/Pu ratio is used as a variable for the fuel optimisation studies. The efficiency of MA transmutation is close to the foreseen theoretical value of 42 kg TW -1 h -1 when level of Pu in the actinide mixture is about 40 wt.%. The obtained results are compared with the reference case of the EFIT core loaded with the composite CERCER fuel, where fuel particles are incorporated in a ceramic magnesia matrix. The results of this study offer additional information for the EFIT fuel selection.

  13. A conceptual optimisation strategy for radiography in a digital environment.

    Science.gov (United States)

    Båth, Magnus; Håkansson, Markus; Hansson, Jonny; Månsson, Lars Gunnar

    2005-01-01

    Using a completely digital environment for the entire imaging process leads to new possibilities for optimisation of radiography since many restrictions of screen/film systems, such as the small dynamic range and the lack of possibilities for image processing, do not apply any longer. However, at the same time these new possibilities lead to a more complicated optimisation process, since more freedom is given to alter parameters. This paper focuses on describing an optimisation strategy that concentrates on taking advantage of the conceptual differences between digital systems and screen/film systems. The strategy can be summarised as: (a) always include the anatomical background during the optimisation, (b) perform all comparisons at a constant effective dose and (c) separate the image display stage from the image collection stage. A three-step process is proposed where the optimal setting of the technique parameters is determined at first, followed by an optimisation of the image processing. In the final step the optimal dose level-given the optimal settings of the image collection and image display stages-is determined.

  14. CT dose optimisation and reduction in osteoarticular disease.

    Science.gov (United States)

    Gervaise, A; Teixeira, P; Villani, N; Lecocq, S; Louis, M; Blum, A

    2013-04-01

    With an improvement in the temporal and spatial resolution, computed tomography (CT) is indicated in the evaluation of a great many osteoarticular diseases. New exploration techniques such as the dynamic CT and CT bone perfusion also provide new indications. However, CT is still an irradiating imaging technique and dose optimisation and reduction remains primordial. In this paper, the authors first present the typical doses delivered during CT in osteoarticular disease. They then discuss the different ways to optimise and reduce these doses by distinguishing the behavioural factors from the technical factors. Among the latter, the optimisation of the milliamps and kilovoltage is indispensable and should be adapted to the type of exploration and the morphotype of each individual. These technical factors also benefit from recent technological evolutions with the distribution of iterative reconstructions. In this way, the dose may be divided by two and provide an image of equal quality. With these dose optimisation and reduction techniques, it is now possible, while maintaining an excellent quality of the image, to obtain low-dose or even very low-dose acquisitions with a dose sometimes similar that of a standard X-ray assessment. Nevertheless, although these technical factors provide a major reduction in the dose delivered, behavioural factors, such as compliance with the indications, remain fundamental. Finally, the authors describe how to optimise and reduce the dose with specific applications in musculoskeletal imaging such as the dynamic CT, CT bone perfusion and dual energy CT.

  15. Hybrid Genetic Algorithm with PSO Effect for Combinatorial Optimisation Problems

    Directory of Open Access Journals (Sweden)

    M. H. Mehta

    2012-12-01

    Full Text Available In engineering field, many problems are hard to solve in some definite interval of time. These problems known as “combinatorial optimisation problems” are of the category NP. These problems are easy to solve in some polynomial time when input size is small but as input size grows problems become toughest to solve in some definite interval of time. Long known conventional methods are not able to solve the problems and thus proper heuristics is necessary. Evolutionary algorithms based on behaviours of different animals and species have been invented and studied for this purpose. Genetic Algorithm is considered a powerful algorithm for solving combinatorial optimisation problems. Genetic algorithms work on these problems mimicking the human genetics. It follows principle of “survival of the fittest” kind of strategy. Particle swarm optimisation is a new evolutionary approach that copies behaviour of swarm in nature. However, neither traditional genetic algorithms nor particle swarm optimisation alone has been completely successful for solving combinatorial optimisation problems. Here a hybrid algorithm is proposed in which strengths of both algorithms are merged and performance of proposed algorithm is compared with simple genetic algorithm. Results show that proposed algorithm works definitely better than the simple genetic algorithm.

  16. A modified lateral-load pattern for pushover analysis of torsion-irregular structures%扭转不规则结构水平侧向力分布模式与pushover分析

    Institute of Scientific and Technical Information of China (English)

    唐玉; 郑七振; 楼梦麟

    2012-01-01

    水平侧向力分布模式的施加问题是合理进行pushover分析的关键环节.对于可以简化为平面模型的结构,传统的水平侧向力分布模式表现出较好的适用性,但对于因扭转不规则而导致必须采用空间模型的结构则并不适用.为此,针对扭转不规则结构的水平侧向力分布模式问题,并基于该类结构的地震响应特征,通过引入水平侧向力调整系数和水平侧向力分配系数,提出了扭转不规则结构改进的水平侧向力分布模式.对一具有典型扭转不规则特性的空间钢框架结构分别进行改进分布模式下的pushover分析和IV类场地典型地震动作用下的弹塑性时程分析,计算结果显示:改进分布模式下的pushover分析体现出扭转效应对结构反应的影响,并在一定程度上反映出更多的结构抗震信息,验证了所格出模式的可行性,说明pushover分析法也同样适用于扭转不规则结构.%The influence of lateral-load pattern on models is a key to pushover analysis. For a structure which can be simplified to a plane model, the traditional lateral-load pattern shows a practical application. But it doesn' t work when it comes to those that must he simulaLed as a space model because of torsion-irregular. Aiming at finding an appropriate lateral-load pattern for pushover analysis of torsion-irregular structures, and based on the seismic response of torsi on-irregular structures, a modified lateral-lode pattern is produced by introducing the lateral-load adjustment coefficient and the lateral-load distribution coefficient. These two coefficients can consider the issue of uneven stiffness distribution and the influence of high order modes respectively. At last, an example using both SAP2000 for pushover analysis and dynamic time-history analysis testifies the feasibility and validity of the proposed model. The result shows that the modified pushover analysis can get more structural seismic information than

  17. Optimising a parallel conjugate gradient solver

    Energy Technology Data Exchange (ETDEWEB)

    Field, M.R. [O`Reilly Institute, Dublin (Ireland)

    1996-12-31

    This work arises from the introduction of a parallel iterative solver to a large structural analysis finite element code. The code is called FEX and it was developed at Hitachi`s Mechanical Engineering Laboratory. The FEX package can deal with a large range of structural analysis problems using a large number of finite element techniques. FEX can solve either stress or thermal analysis problems of a range of different types from plane stress to a full three-dimensional model. These problems can consist of a number of different materials which can be modelled by a range of material models. The structure being modelled can have the load applied at either a point or a surface, or by a pressure, a centrifugal force or just gravity. Alternatively a thermal load can be applied with a given initial temperature. The displacement of the structure can be constrained by having a fixed boundary or by prescribing the displacement at a boundary.

  18. Helminths infection patterns in a lizard (Tropidurus hispidus) population from a semiarid neotropical area: associations between female reproductive allocation and parasite loads.

    Science.gov (United States)

    Galdino, Conrado A B; Ávila, Robson W; Bezerra, Castiele H; Passos, Daniel C; Melo, Gabriela C; Zanchi-Silva, Djan

    2014-12-01

    This study reports helminth infection patterns of the lizard Tropidurus hispidus from an area of semiarid caatinga in northeastern Brazil (Ceará state). The lizard population was parasitized by 8 helminth species, and the species composition of the component community resembles that found for other Neotropical lizards. The prevalence of parasites was higher for males compared with females, whereas no relation was found between intensity of infection of 2 parasites (Parapharyngodon alvarengai and Physaloptera lutzi) and the lizards body size. For reproductive females, parasite infection intensity was negatively correlated to reproductive investment.

  19. Transmit Power Optimisation in Wireless Network

    Directory of Open Access Journals (Sweden)

    Besnik Terziu

    2011-09-01

    Full Text Available Transmit power optimisation in wireless networks based on beamforming have emerged as a promising technique to enhance the spectrum efficiency of present and future wireless communication systems. The aim of this study is to minimise the access point power consumption in cellular networks while maintaining a targeted quality of service (QoS for the mobile terminals. In this study, the targeted quality of service is delivered to a mobile station by providing a desired level of Signal to Interference and Noise Ratio (SINR. Base-stations are coordinated across multiple cells in a multi-antenna beamforming system. This study focuses on a multi-cell multi-antenna downlink scenario where each mobile user is equipped with a single antenna, but where multiple mobile users may be active simultaneously in each cell and are separated via spatial multiplexing using beamforming. The design criteria is to minimize the total weighted transmitted power across the base-stations subject to SINR constraints at the mobile users. The main contribution of this study is to define an iterative algorithm that is capable of finding the joint optimal beamformers for all basestations, based on a correlation-based channel model, the full-correlation model. Among all correlated channel models, the correlated channel model used in this study is the most accurate, giving the best performance in terms of power consumption. The environment here in this study is chosen to be Non-Light of- Sight (NLOS condition, where a signal from a wireless transmitter passes several obstructions before arriving at a wireless receiver. Moreover there are many scatterers local to the mobile, and multiple reflections can occur among them before energy arrives at the mobile. The proposed algorithm is based on uplink-downlink duality using the Lagrangian duality theory. Time-Division Duplex (TDD is chosen as the platform for this study since it has been adopted to the latest technologies in Fourth

  20. Multiobjective design optimisation of coronary stents.

    Science.gov (United States)

    Pant, Sanjay; Limbert, Georges; Curzen, Nick P; Bressloff, Neil W

    2011-11-01

    representative CYPHER stent are shown. The methodology and the results of this work could potentially be useful in further optimisation studies and development of a family of stents with increased resistance to in-stent restenosis and thrombosis.

  1. Topology Optimisation of Wideband Coaxial-to-Waveguide Transitions

    Science.gov (United States)

    Hassan, Emadeldeen; Noreland, Daniel; Wadbro, Eddie; Berggren, Martin

    2017-03-01

    To maximize the matching between a coaxial cable and rectangular waveguides, we present a computational topology optimisation approach that decides for each point in a given domain whether to hold a good conductor or a good dielectric. The conductivity is determined by a gradient-based optimisation method that relies on finite-difference time-domain solutions to the 3D Maxwell’s equations. Unlike previously reported results in the literature for this kind of problems, our design algorithm can efficiently handle tens of thousands of design variables that can allow novel conceptual waveguide designs. We demonstrate the effectiveness of the approach by presenting optimised transitions with reflection coefficients lower than -15 dB over more than a 60% bandwidth, both for right-angle and end-launcher configurations. The performance of the proposed transitions is cross-verified with a commercial software, and one design case is validated experimentally.

  2. Fabrication optimisation of carbon fiber electrode with Taguchi method.

    Science.gov (United States)

    Cheng, Ching-Ching; Young, Ming-Shing; Chuang, Chang-Lin; Chang, Ching-Chang

    2003-07-01

    In this study, we describe an optimised procedure for fabricating carbon fiber electrodes using Taguchi quality engineering method (TQEM). The preliminary results show a S/N ratio improvement from 22 to 30 db (decibel). The optimised parameter was tested by using a glass micropipette (0.3 mm outer/2.5 mm inner length of carbon fiber) dipped into PBS solution under 2.9 V triangle-wave electrochemical processing for 15 s, followed by coating treatment of micropipette on 2.6 V DC for 45 s in 5% Nafion solution. It is thus shown that Taguchi process optimisation can improve cost, manufacture time and quality of carbon fiber electrodes.

  3. Quasi-combinatorial energy landscapes for nanoalloy structure optimisation.

    Science.gov (United States)

    Schebarchov, D; Wales, D J

    2015-11-14

    We formulate nanoalloy structure prediction as a mixed-variable optimisation problem, where the homotops can be associated with an effective, quasi-combinatorial energy landscape in permutation space. We survey this effective landscape for a representative set of binary systems modelled by the Gupta potential. In segregating systems with small lattice mismatch, we find that homotops have a relatively straightforward landscape with few local optima - a scenario well-suited for local (combinatorial) optimisation techniques that scale quadratically with system size. Combining these techniques with multiple local-neighbourhood structures yields a search for multiminima, and we demonstrate that generalised basin-hopping with a metropolis acceptance criterion in the space of multiminima can then be effective for global optimisation of binary and ternary nanoalloys.

  4. Microfluidic converging/diverging channels optimised for homogeneous extensional deformation

    Science.gov (United States)

    Zografos, K.; Oliveira, M. S. N.

    2016-01-01

    In this work, we optimise microfluidic converging/diverging geometries in order to produce constant strain-rates along the centreline of the flow, for performing studies under homogeneous extension. The design is examined for both two-dimensional and three-dimensional flows where the effects of aspect ratio and dimensionless contraction length are investigated. Initially, pressure driven flows of Newtonian fluids under creeping flow conditions are considered, which is a reasonable approximation in microfluidics, and the limits of the applicability of the design in terms of Reynolds numbers are investigated. The optimised geometry is then used for studying the flow of viscoelastic fluids and the practical limitations in terms of Weissenberg number are reported. Furthermore, the optimisation strategy is also applied for electro-osmotic driven flows, where the development of a plug-like velocity profile allows for a wider region of homogeneous extensional deformation in the flow field. PMID:27478523

  5. Analysis and optimisation of heterogeneous real-time embedded systems

    DEFF Research Database (Denmark)

    Pop, Paul; Eles, Petru; Peng, Zebo

    2005-01-01

    . The success of such new design methods depends on the availability of analysis and optimisation techniques. Analysis and optimisation techniques for heterogeneous real-time embedded systems are presented in the paper. The authors address in more detail a particular class of such systems called multi......An increasing number of real-time applications are today implemented using distributed heterogeneous architectures composed of interconnected networks of processors. The systems are heterogeneous, not only in terms of hardware components, but also in terms of communication protocols and scheduling......-clusters, composed of several networks interconnected via gateways. They present a schedulability analysis for safety-critical applications distributed on multi-cluster systems and briefly highlight characteristic design optimisation problems: the partitioning and mapping of functionality, and the packing...

  6. Analysis and optimisation of heterogeneous real-time embedded systems

    DEFF Research Database (Denmark)

    Pop, Paul; Eles, Petru; Peng, Zebo

    2006-01-01

    . The success of such new design methods depends on the availability of analysis and optimisation techniques. Analysis and optimisation techniques for heterogeneous real-time embedded systems are presented in the paper. The authors address in more detail a particular class of such systems called multi......An increasing number of real-time applications are today implemented using distributed heterogeneous architectures composed of interconnected networks of processors. The systems are heterogeneous, not only in terms of hardware components, but also in terms of communication protocols and scheduling......-clusters, composed of several networks interconnected via gateways. They present a schedulability analysis for safety-critical applications distributed on multi-cluster systems and briefly highlight characteristic design optimisation problems: the partitioning and mapping of functionality, and the packing...

  7. Effect of lifting height and load mass on low back loading.

    Science.gov (United States)

    Hoozemans, Marco J M; Kingma, Idsart; de Vries, Wiebe H K; van Dieën, Jaap H

    2008-07-01

    The objective of this study was to quantify the effect of lifting height and mass lifted on the peak low back load in terms of net moments, compression forces and anterior-posterior shear forces. Ten participants had to lift a box using four handle heights. Low back loading was quantified using a dynamic 3-D linked segment model and a detailed electromyographic driven model of the trunk musculature. The effects of lifting height and lifting mass were quantified using a regression technique (GEE) for correlated data. Results indicate that an increase in lifting height and a decrease in lifting mass were related to a decrease in low back load. It is argued that trunk flexion is a major contributor to low back load. For ergonomic interventions it can be advised to prioritise optimisation of the vertical location of the load to be lifted rather than decreasing the mass of the load for handle heights between 32 cm and 155 cm, and for load masses between 7.5 and 15 kg. Lifting height and load mass are important determinants of low back load during manual materials handling. This paper provides the quantitative effect of lifting height and mass lifted, the results of which can be used by ergonomists at the workplace to evaluate interventions regarding lifting height and load mass.

  8. Evaluation of morphology, aggregation pattern and size-dependent drug-loading efficiency of gold nanoparticles stabilised with poly (2-vinyl pyridine)

    Science.gov (United States)

    Rahim, Sana; Ali, Syed Abid; Ahmed, Farid; Imran, Muhammad; Shah, Muhammad Raza; Malik, Muhammad Imran

    2017-07-01

    Presence of basic nitrogen throughout the chain of poly(2-vinylpyridine) make them alluring candidate for applications requiring chelation of heavy metals. In this study, we report the use of poly (2-vinylpyridine) (P2VP) homopolymers of varying molar masses for the stabilization of gold nanoparticles for the first time. A study based on AFM, DLS and UV-visible spectroscopy was conducted to establish a correlation of the molar mass of P2VP with the size and distribution of the gold nanoparticles. Systematic and gradual change in the absorbance intensity and shift in SPR band of gold nanoparticles were also observed upon variations in treatment temperature, concentration of polymer, residence time, pH, and electrolyte concentration. The results obtained by UV-visible spectroscopy, AFM and DLS are complementary. The size of the P2VP-stabilised AuNPs was found to be in the range of 20-130 nms. At last, the effect of the size of P2VP-stabilised AuNPs (directly related to the molar mass of P2VP) on the drug-loading efficiency is evaluated. [Figure not available: see fulltext.

  9. Structure and weights optimisation of a modified Elman network emotion classifier using hybrid computational intelligence algorithms: a comparative study

    Science.gov (United States)

    Sheikhan, Mansour; Abbasnezhad Arabi, Mahdi; Gharavian, Davood

    2015-10-01

    Artificial neural networks are efficient models in pattern recognition applications, but their performance is dependent on employing suitable structure and connection weights. This study used a hybrid method for obtaining the optimal weight set and architecture of a recurrent neural emotion classifier based on gravitational search algorithm (GSA) and its binary version (BGSA), respectively. By considering the features of speech signal that were related to prosody, voice quality, and spectrum, a rich feature set was constructed. To select more efficient features, a fast feature selection method was employed. The performance of the proposed hybrid GSA-BGSA method was compared with similar hybrid methods based on particle swarm optimisation (PSO) algorithm and its binary version, PSO and discrete firefly algorithm, and hybrid of error back-propagation and genetic algorithm that were used for optimisation. Experimental tests on Berlin emotional database demonstrated the superior performance of the proposed method using a lighter network structure.

  10. Use of an electronic finger dosimeters in optimisation of finger doses

    Energy Technology Data Exchange (ETDEWEB)

    Martin, C. J.; Whitby, M.; Hilditch, T.; Anstee, D.

    2002-07-01

    Optimisation of radiation doses to the hands is problematic. Doses recorded by passive dosimeters include contributions from many different manipulations, so it is difficult to ascertain which actions make significant contributions to the doses received. A device for electronic monitoring of finger doses called and Advanced Extremity Gamma Instrumentation system (AEGIS), which records instantaneous dose rates at the finger, can assist in providing this information. AEGIS ha been employed in a number of hospital departments where radionuclides are used, including a large hospital radionuclide dispensary and nuclear medicine departments. Data were recorded throughout complete sessions and analysed to identify the actions which made the most significant contributions to doses. Study of the patterns of radiation dose rate has enabled finger doses in the radionuclide dispensary to be optimised through raising staff awareness of doses from each manipulation. Optimisation has been achieved through changes following evaluation of alternative manipulation techniques and use of shielding devices. AEGIS has also been used to determine dose distributions across the hand and establish a relationship between the dose to the most exposed part and that at the monitoring position. For radionuclide dispensary staff, the tip of the index finger on the dominant hand receives the highest dose. Studies carried out in nuclear medicine departments have shown that withdrawals of radiopharmaceutical into a syringe, where a shield is not used routinely, tend to make the largest contribution to the dose. This can vary from 5 to 500 {mu}Gy per manipulation. Doses for injections varied from 1.5 to 300{mu}Gy. (Author)

  11. Optimising location of unified power flow controllers by means of improved evolutionary programming

    Energy Technology Data Exchange (ETDEWEB)

    Hao, J.; Chen, C. [Shanghai Jiaotong Univ. (China). Dept. of Electrical Engineering; Shi, L.B. [Hong Kong Univ. (China). Dept. of Electrical and Electronic Engineering

    2004-11-01

    The unified power flow controller (UPFC) is one of the most promising Flexible AC Transmission Systems (FACTS) devices for the load flow control. Simultaneous optimisation of location and parameters for UPFCs is an important issue when the given number of UPFCs is applied to the power system with the purpose of increasing system loadability. This paper presents a mathematical model about optimal location and parameters of UPFCs to maximise the system loadability subject to the transmission line capacity limits and specified voltage level. An improved computational intelligence approach: self-adaptive evolutionary programming (SAEP) is used to solve the nonlinear programming problem presented above for better accuracy. Case studies of the IEEE 30- and 118-bus systems using the proposed model and technique demonstrate that the proposed mathematical model is corrective and efficient. Furthermore, steady-state performance of power system can be effectively enhanced due to the optimal location and parameters of UPFCs. (author)

  12. Numerical optimisation of friction stir welding: review of future challenges

    DEFF Research Database (Denmark)

    Tutum, Cem Celal; Hattel, Jesper Henri

    2011-01-01

    During the last decade, the combination of increasingly more advanced numerical simulation software with high computational power has resulted in models for friction stir welding (FSW), which have improved the understanding of the determining physical phenomena behind the process substantially....... This has made optimisation of certain process parameters possible and has in turn led to better performing friction stir welded products, thus contributing to a general increase in the popularity of the process and its applications. However, most of these optimisation studies do not go well beyond manual...

  13. Alternatives for optimisation of rumen fermentation in ruminants

    Directory of Open Access Journals (Sweden)

    T. Slavov

    2017-06-01

    Full Text Available Abstract. The proper knowledge on the variety of events occurring in the rumen makes possible their optimisation with respect to the complete feed conversion and increasing the productive performance of ruminants. The inclusion of various dietary additives (supplements, biologically active substances, nutritional antibiotics, probiotics, enzymatic preparations, plant extracts etc. has an effect on the intensity and specific pathway of fermentation, and thus, on the general digestion and systemic metabolism. The optimisation of rumen digestion is a method with substantial potential for improving the efficiency of ruminant husbandry, increasing of quality of their produce and health maintenance.

  14. Separative power of an optimised concurrent gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Bogovalov, Sergey; Boman, Vladimir [National Research Nuclear University (MEPHI), Moscow (Russian Federation)

    2016-06-15

    The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to δU = 12.7 (V/700 m/s)2(300 K/T)(L/1 m) kg·SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

  15. Separative Power of an Optimised Concurrent Gas Centrifuge

    Directory of Open Access Journals (Sweden)

    Sergey Bogovalov

    2016-06-01

    Full Text Available The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to δU = 12.7 (V/700 m/s2(300 K/T(L/1 m kg·SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

  16. Multiscale Analysis and Optimisation of Photosynthetic Solar Energy Systems

    CERN Document Server

    Ringsmuth, Andrew K

    2014-01-01

    This work asks how light harvesting in photosynthetic systems can be optimised for economically scalable, sustainable energy production. Hierarchy theory is introduced as a system-analysis and optimisation tool better able to handle multiscale, multiprocess complexities in photosynthetic energetics compared with standard linear-process analysis. Within this framework, new insights are given into relationships between composition, structure and energetics at the scale of the thylakoid membrane, and also into how components at different scales cooperate under functional objectives of the whole photosynthetic system. Combining these reductionistic and holistic analyses creates a platform for modelling multiscale-optimal, idealised photosynthetic systems in silico.

  17. Optimisation of BPMN Business Models via Model Checking

    DEFF Research Database (Denmark)

    Herbert, Luke Thomas; Sharp, Robin

    2013-01-01

    We present a framework for the optimisation of business processes modelled in the business process modelling language BPMN, which builds upon earlier work, where we developed a model checking based method for the analysis of BPMN models. We define a structure for expressing optimisation goals...... candidate improved processes based on the fittest of the previous generation. The evaluation of the fitness of each candidate in a generation is performed via model checking, detailed in previous work. At each iteration, this allows the determination of the precise numerical evaluation of the performance...

  18. Optimisation of beam-orientations in conformal radiotherapy treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Rowbottom, C.G

    1999-07-01

    Many synergistic advances have led to the beginnings of the routine use of conformal radiotherapy. These include advances in diagnostic imaging, in 3D treatment planning, in the technology for complex treatment delivery and in computer assessment of rival treatment plans. A conformal radiotherapy treatment plan more closely conforms the high-dose volume to the target volume, reducing the dose to normal healthy tissue. Traditionally, human planners have devised the treatment parameters used in radiotherapy treatment plans via a manually iterative process. Computer 'optimisation' algorithms have been shown to improve treatment plans as they can explore much more of the search space in a relatively short time. This thesis examines beam-orientation computer 'optimisation' in radiotherapy treatment planning and several new techniques were developed. Using these techniques a comparison was performed between treatment plans with 'standard', fixed beam-orientations and treatment plans with 'optimised' beam-orientations for patients with cancer of the prostate, oesophagus and brain. Plans were compared on the basis of dose-distributions and in some cases biological models for the probability of damage to the target volume and the major organs-at-risk (OARs) in each patient group. A cohort of patients was considered in each group to avoid bias from a specific patient geometry. In the case of the patient cohort with cancer of the prostate, a coplanar beam-orientation 'optimisation' scheme led to an average increase in the TCP of (5.7{+-}1.4)% compared to the standard plans after the dose to the isocentre had been scaled to produce a rectal NTCP of 1%. For the patient cohort with cancer of the oesophagus, the beam-orientation 'optimisation' scheme reduced the average lung NTCP by (0.7{+-}0.2)% at the expense of a modest increase in the average spinal cord NTCP of (0.1{+-}0.2)%. A non-coplanar beam-orientation 'optimisation

  19. Plant-wide performance optimisation – The refrigeration system case

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Green, Torben; Razavi-Far, Roozbeh

    2012-01-01

    This paper investigates the problem of plant-wide performance optimisation seen from an industrial perspective. The refrigeration system is used as a case study, because it has a distributed control architecture and operates in steady state conditions, which is common for many industrial applicat......This paper investigates the problem of plant-wide performance optimisation seen from an industrial perspective. The refrigeration system is used as a case study, because it has a distributed control architecture and operates in steady state conditions, which is common for many industrial...

  20. An Improved Lower Bound Limit State Optimisation Algorithm

    DEFF Research Database (Denmark)

    Frier, Christian; Damkilde, Lars

    2010-01-01

    Limit State analysis has been used in engineering practice for many years e.g. the yield-line method for concrete slabs and slip-line solutions in geotechnics. In the recent years there has been an increased interest in numerical Limit State analysis, and today algorithms take into account the non......-linear yield criteria. The aim of the paper is to refine an earlier presented effective method which reduces the number of optimisation variables considerably by eliminating the equilibrium equations a priori and improvements are made on the interior point optimisation algorithm....

  1. Robust eigenstructure clustering by non-smooth optimisation

    Science.gov (United States)

    Dao, Minh Ngoc; Noll, Dominikus; Apkarian, Pierre

    2015-08-01

    We extend classical eigenstructure assignment to more realistic problems, where additional performance and robustness specifications arise. Our aim is to combine time-domain constraints, as reflected by pole location and eigenvector structure, with frequency-domain objectives such as the H2, H∞ or Hankel norms. Using pole clustering, we allow poles to move in polydisks of prescribed size around their nominal values, driven by optimisation. Eigenelements, that is poles and eigenvectors, are allowed to move simultaneously and serve as decision variables in a specialised non-smooth optimisation technique. Two aerospace applications illustrate the power of the new method.

  2. 根据效率曲线及负载特点合理配置扶梯主机%Configuration of Escalator Machine Based on Efficiency Curve and Load Pattern

    Institute of Scientific and Technical Information of China (English)

    陈正

    2014-01-01

    叙述了扶梯的负载特点、扶梯主机效率曲线的应用、扶梯主机损耗和效率的影响因素、电机和减速箱的类型及其在扶梯中的应用特点,给扶梯主机的合理配置和节能应用提供了实用性的参考建议。%Describe escalator load pattern characters, escalator machine efficiency curve, escalator machine power loss and efficiency impact factors, analyze motor and gearbox type and respective application purpose for escalator, recommend practical reference comment for escalator machine reasonable configuration and energy-saving application.

  3. Optimisation of Oil Production in Two – Phase Flow Reservoir Using Simultaneous Method and Interior Point Optimiser

    DEFF Research Database (Denmark)

    2012-01-01

    in the reservoir. A promising decrease of these remained resources can be provided by smart wells applying water injections to sustain satisfactory pressure level in the reservoir throughout the whole process of oil production. Basically to enhance secondary recovery of the remaining oil after drilling, water...... fields, or closed loop optimisation, can be used for optimising the reservoir performance in terms of net present value of oil recovery or another economic objective. In order to solve an optimal control problem we use a direct collocation method where we translate a continuous problem into a discrete...... for large scale nonlinear optimisation was applied. Because of its versatile compatibility with programming technologies, a C++ programming language in Microsoft Visual Studio integrated development environment was used for modelling the optimal control problem. Thanks to object oriented features...

  4. Solving dynamic multi-objective problems with vector evaluated particle swarm optimisation

    CSIR Research Space (South Africa)

    Greeff, M

    2008-06-01

    Full Text Available Many optimisation problems are multi-objective and change dynamically. Many methods use a weighted average approach to the multiple objectives. This paper introduces the usage of the vector evaluated particle swarm optimiser (VEPSO) to solve dynamic...

  5. Agent-Based Decision Control—How to Appreciate Multivariate Optimisation in Architecture

    DEFF Research Database (Denmark)

    Negendahl, Kristoffer; Perkov, Thomas Holmer; Kolarik, Jakub

    2015-01-01

    in the early design stage. The main focus is to demonstrate the optimisation method, which is done in two ways. Firstly, the newly developed agent-based optimisation algorithm named Moth is tested on three different single objective search spaces. Here Moth is compared to two evolutionary algorithms. Secondly......, the method is applied to a multivariate optimisation problem. The aim is specifically to demonstrate optimisation for entire building energy consumption, daylight distribution and capital cost. Based on the demonstrations Moth’s ability to find local minima is discussed. It is concluded that agent-based...... optimisation algorithms like Moth open up for new uses of optimisation in the early design stage. With Moth the final outcome is less dependent on pre- and post-processing, and Moth allows user intervention during optimisation. Therefore, agent-based models for optimisation such as Moth can be a powerful...

  6. Optimising hydrogen bonding in solid wood

    DEFF Research Database (Denmark)

    Engelund, Emil Tang

    2009-01-01

    The chemical bonds of wood are both covalent bonds within the wood polymers and hydrogen bonds within and between the polymers. Both types of bonds are responsible for the coherence, strength and stiffness of the material. The hydrogen bonds are more easily modified by changes in load, moisture...... and temperature. The distribution of bond lengths was examined using infrared spectroscopy (ATR-FTIR) both prior to treatments and after. The results show that the absorbance bands of the spectra related to the hydroxyl and carboxyl stretching vibrations were changed by the treatments. Apparently, the first...

  7. Optimisation of component performance via structuring

    Directory of Open Access Journals (Sweden)

    Psyk Verena

    2015-01-01

    Full Text Available Ecological and economic reasons are forcing industry to improve efficiency and to save energy and resources by reducing product weight. In current product designs often insufficient geometric stiffness of the part prohibits exploiting the full potential of weight reduction offered by modern materials. Ideally adapting the geometry to the load profile by implementing appropriate structures often allows a wall thickness and weight reduction and improves the acoustic properties. To enable a target-oriented design, structures manufactured by working media and working energy based forming technologies were analysed.

  8. Load Carriage and the Female Soldier

    Directory of Open Access Journals (Sweden)

    Venerina Johnson

    2011-07-01

    Full Text Available This paper reviews the physiological, biomechanical and health impacts of load carriage on the female soldier and extends to include issues acknowledged as impacting on the female athlete and hence the female soldier. Physiological factors such as fat mass, strength, aerobic endurance and biomechanical factors such as stride length and forward lean have the potential to increase the energy cost of load carriage and cause injury. The female athlete triad, iron deficiency, pelvic floor muscle dysfunction and military equipment issues can likewise reduce female soldier performance and increase injury risk. Research evidence is presented to inform the development and implementation of performance optimisation and injury prevention strategies. Discussed strategies include structured physical conditioning, improving nutrition and hydration practices and modification of load carriage equipment to meet female soldier requirements.

  9. Hierarchical ZnO Nanowires-loaded Sb-doped SnO2-ZnO Micrograting Pattern via Direct Imprinting-assisted Hydrothermal Growth and Its Selective Detection of Acetone Molecules.

    Science.gov (United States)

    Choi, Hak-Jong; Choi, Seon-Jin; Choo, Soyoung; Kim, Il-Doo; Lee, Heon

    2016-01-08

    We propose a novel synthetic route by combining imprinting transfer of a Sb-doped SnO2 (ATO)-ZnO composite micrograting pattern (MP), i.e., microstrip lines, on a sensor substrate and subsequent hydrothermal growth of ZnO nanowires (NWs) for producing a hierarchical ZnO NW-loaded ATO-ZnO MP as an improved chemo-resistive sensing layer. Here, ATO-ZnO MP structure with 3-μm line width, 9-μm pitch, and 6-μm height was fabricated by direct transfer of mixed ATO and ZnO nanoparticle (NP)-dispersed resists, which are pre-patterned on a polydimethylsiloxane (PDMS) mold. ZnO NWs with an average diameter of less than 50 nm and a height of 250 nm were quasi-vertically grown on the ATO-ZnO MP, leading to markedly enhanced surface area and heterojunction composites between each ATO NP, ZnO NP, and ZnO NW. A ZnO NW-loaded MP sensor with a relative ratio of 1:9 between ATO and ZnO (1:9 ATO-ZnO), exhibited highly sensitive and selective acetone sensing performance with 2.84-fold higher response (R air/R gas = 12.8) compared to that (R air/R gas = 4.5) of pristine 1:9 ATO-ZnO MP sensor at 5 ppm. Our results demonstrate the processing advantages of direct imprinting-assisted hydrothermal growth for large-scale homogeneous coating of hierarchical oxide layers, particularly for applications in highly sensitive and selective chemical sensors.

  10. Iron load

    Directory of Open Access Journals (Sweden)

    Filippo Cassarà

    2013-03-01

    Full Text Available Recent research addressed the main role of hepcidin in the regulation of iron metabolism. However, while this mechanism could be relevant in causing iron load in Thalassemia Intermedia and Sickle-Cell Anemia, its role in Thalassemia Major (TM is marginal. This is mainly due to the high impact of transfusional requirement into the severe increase of body iron. Moreover, the damage of iron load may be worsened by infections, as HCV hepatitis, or liver and endocrinological damage. One of the most relevant associations was found between splenectomy and increase of risk for mortality due,probably, to more severe iron load. These issues suggest as morbidity and mortality of this group of patients they do not depend only by our ability in controlling heart damage but even in preventing or treating particular infections and complications. This finding is supported by the impairment of survival curves in patients with complications different from heart damage. However, because, during recent years different direct and indirect methods to detect iron overload in patients affected by secondary hemochromatosis have been implemented, our ability to maintain under control iron load is significantly improved. Anyway, the future in iron load management remains to be able to have an iron load map of our body for targeting chelation and other medical treatment according to the single organ damage.

  11. Non-linear Total Energy Optimisation of a Fleet of Power Plants

    Science.gov (United States)

    Nolle, Lars; Biegler-König, Friedrich; Deeskow, Peter

    In order to optimise the energy production in a fleet of power plants, it is necessary to solve a mixed integer optimisation problem. Traditionally, the continuous parts of the problem are linearized and a Simplex scheme is applied. Alternatively, heuristic "bionic" optimisation methods can be used without having to linearize the problem. Weare going to demonstrate this approach by modelling power plant blocks with fast Neural Networks and optimising the operation of multi-block power plants over one day with Simulated Annealing.

  12. Optimisation of a novel trailing edge concept for a high lift device

    CSIR Research Space (South Africa)

    Botha, JDM

    2014-09-01

    Full Text Available A novel concept (referred to as the flap extension) is implemented on the leading edge of the flap of a three element high lift device. The concept is optimised using two optimisation approaches based on Genetic Algorithm optimisations. A zero order...

  13. Modern multicore and manycore architectures: Modelling, optimisation and benchmarking a multiblock CFD code

    Science.gov (United States)

    Hadade, Ioan; di Mare, Luca

    2016-08-01

    Modern multicore and manycore processors exhibit multiple levels of parallelism through a wide range of architectural features such as SIMD for data parallel execution or threads for core parallelism. The exploitation of multi-level parallelism is therefore crucial for achieving superior performance on current and future processors. This paper presents the performance tuning of a multiblock CFD solver on Intel SandyBridge and Haswell multicore CPUs and the Intel Xeon Phi Knights Corner coprocessor. Code optimisations have been applied on two computational kernels exhibiting different computational patterns: the update of flow variables and the evaluation of the Roe numerical fluxes. We discuss at great length the code transformations required for achieving efficient SIMD computations for both kernels across the selected devices including SIMD shuffles and transpositions for flux stencil computations and global memory transformations. Core parallelism is expressed through threading based on a number of domain decomposition techniques together with optimisations pertaining to alleviating NUMA effects found in multi-socket compute nodes. Results are correlated with the Roofline performance model in order to assert their efficiency for each distinct architecture. We report significant speedups for single thread execution across both kernels: 2-5X on the multicore CPUs and 14-23X on the Xeon Phi coprocessor. Computations at full node and chip concurrency deliver a factor of three speedup on the multicore processors and up to 24X on the Xeon Phi manycore coprocessor.

  14. Mobile app and app store analysis, testing and optimisation

    OpenAIRE

    Harman, M.; Al-Subaihin, A.; Jia, Y.; Martin, W.; Sarro, F.; Zhang, Y.

    2016-01-01

    This talk presents results on analysis and testing of mobile apps and app stores, reviewing the work of the UCL App Analysis Group (UCLappA) on App Store Mining and Analysis. The talk also covers the work of the UCL CREST centre on Genetic Improvement, applicable to app improvement and optimisation.

  15. Optimisation of sampling windows design for population pharmacokinetic experiments.

    Science.gov (United States)

    Ogungbenro, Kayode; Aarons, Leon

    2008-08-01

    This paper describes an approach for optimising sampling windows for population pharmacokinetic experiments. Sampling windows designs are more practical in late phase drug development where patients are enrolled in many centres and in out-patient clinic settings. Collection of samples under the uncontrolled environment at these centres at fixed times may be problematic and can result in uninformative data. Population pharmacokinetic sampling windows design provides an opportunity to control when samples are collected by allowing some flexibility and yet provide satisfactory parameter estimation. This approach uses information obtained from previous experiments about the model and parameter estimates to optimise sampling windows for population pharmacokinetic experiments within a space of admissible sampling windows sequences. The optimisation is based on a continuous design and in addition to sampling windows the structure of the population design in terms of the proportion of subjects in elementary designs, number of elementary designs in the population design and number of sampling windows per elementary design is also optimised. The results obtained showed that optimal sampling windows designs obtained using this approach are very efficient for estimating population PK parameters and provide greater flexibility in terms of when samples are collected. The results obtained also showed that the generalized equivalence theorem holds for this approach.

  16. Plant-wide performance optimisation – The refrigeration system case

    DEFF Research Database (Denmark)

    Green, Torben; Razavi-Far, Roozbeh; Izadi-Zamanabadi, Roozbeh;

    2012-01-01

    This paper investigates the problem of plant-wide performance optimisation seen from an industrial perspective. The refrigeration system is used as a case study, because it has a distributed control architecture and operates in steady state conditions, which is common for many industrial applicat...

  17. Evaluation of a high throughput starch analysis optimised for wood.

    Directory of Open Access Journals (Sweden)

    Chandra Bellasio

    Full Text Available Starch is the most important long-term reserve in trees, and the analysis of starch is therefore useful source of physiological information. Currently published protocols for wood starch analysis impose several limitations, such as long procedures and a neutralization step. The high-throughput standard protocols for starch analysis in food and feed represent a valuable alternative. However, they have not been optimised or tested with woody samples. These have particular chemical and structural characteristics, including the presence of interfering secondary metabolites, low reactivity of starch, and low starch content. In this study, a standard method for starch analysis used for food and feed (AOAC standard method 996.11 was optimised to improve precision and accuracy for the analysis of starch in wood. Key modifications were introduced in the digestion conditions and in the glucose assay. The optimised protocol was then evaluated through 430 starch analyses of standards at known starch content, matrix polysaccharides, and wood collected from three organs (roots, twigs, mature wood of four species (coniferous and flowering plants. The optimised protocol proved to be remarkably precise and accurate (3%, suitable for a high throughput routine analysis (35 samples a day of specimens with a starch content between 40 mg and 21 µg. Samples may include lignified organs of coniferous and flowering plants and non-lignified organs, such as leaves, fruits and rhizomes.

  18. Evaluation of a high throughput starch analysis optimised for wood.

    Science.gov (United States)

    Bellasio, Chandra; Fini, Alessio; Ferrini, Francesco

    2014-01-01

    Starch is the most important long-term reserve in trees, and the analysis of starch is therefore useful source of physiological information. Currently published protocols for wood starch analysis impose several limitations, such as long procedures and a neutralization step. The high-throughput standard protocols for starch analysis in food and feed represent a valuable alternative. However, they have not been optimised or tested with woody samples. These have particular chemical and structural characteristics, including the presence of interfering secondary metabolites, low reactivity of starch, and low starch content. In this study, a standard method for starch analysis used for food and feed (AOAC standard method 996.11) was optimised to improve precision and accuracy for the analysis of starch in wood. Key modifications were introduced in the digestion conditions and in the glucose assay. The optimised protocol was then evaluated through 430 starch analyses of standards at known starch content, matrix polysaccharides, and wood collected from three organs (roots, twigs, mature wood) of four species (coniferous and flowering plants). The optimised protocol proved to be remarkably precise and accurate (3%), suitable for a high throughput routine analysis (35 samples a day) of specimens with a starch content between 40 mg and 21 µg. Samples may include lignified organs of coniferous and flowering plants and non-lignified organs, such as leaves, fruits and rhizomes.

  19. Evaluation of a High Throughput Starch Analysis Optimised for Wood

    Science.gov (United States)

    Bellasio, Chandra; Fini, Alessio; Ferrini, Francesco

    2014-01-01

    Starch is the most important long-term reserve in trees, and the analysis of starch is therefore useful source of physiological information. Currently published protocols for wood starch analysis impose several limitations, such as long procedures and a neutralization step. The high-throughput standard protocols for starch analysis in food and feed represent a valuable alternative. However, they have not been optimised or tested with woody samples. These have particular chemical and structural characteristics, including the presence of interfering secondary metabolites, low reactivity of starch, and low starch content. In this study, a standard method for starch analysis used for food and feed (AOAC standard method 996.11) was optimised to improve precision and accuracy for the analysis of starch in wood. Key modifications were introduced in the digestion conditions and in the glucose assay. The optimised protocol was then evaluated through 430 starch analyses of standards at known starch content, matrix polysaccharides, and wood collected from three organs (roots, twigs, mature wood) of four species (coniferous and flowering plants). The optimised protocol proved to be remarkably precise and accurate (3%), suitable for a high throughput routine analysis (35 samples a day) of specimens with a starch content between 40 mg and 21 µg. Samples may include lignified organs of coniferous and flowering plants and non-lignified organs, such as leaves, fruits and rhizomes. PMID:24523863

  20. Optimisation of Kinematics for Tracked Vehicle Hydro Gas Suspension System

    Directory of Open Access Journals (Sweden)

    S. Sridhar

    2006-11-01

    Full Text Available The modern-day armoured fighting vehicles (AFVs are basically tracked vehicles equippedwith hydro gas suspensions, in lieu of conventional mechanical suspensions like torsion barand coil spring bogie suspensions. The uniqueness of hydro gas suspension is that it offersa nonlinear spring rate, which is very much required for the cross-country moveability of atracked vehicle. The AFVs have to negotiate different cross-country terrains like sandy, rocky,riverbed, etc. and the road irregularities provide enumerable problems during dynamic loadingsto the design of hydro gas suspension system. Optimising various design parameters demandsinnovative design methodologies to achieve better ride performance. Hence, a comprehensivekinematic analysis is needed. In this study, a methodology has been derived to optimise thekinematics of the suspension by reorienting the cylinder axis and optimising the loadtransferringleverage factor so that the side thrust on the cylinder is minimised to a greaterextent. The optimisation ultimately increases the life of the high-pressure and high-temperaturepiston seals, resulting in enhanced system life for better dependability.

  1. Cluster Optimisation using Cgroups at a Tier-2

    Science.gov (United States)

    Qin, G.; Roy, G.; Crooks, D.; Skipsey, S. C.; Stewart, G. P.; Britton, D.

    2016-10-01

    The Linux kernel feature Control Groups (cgroups) has been used to gather metrics on the resource usage of single and eight-core ATLAS workloads. It has been used to study the effects on performance of a reduction in the amount of physical memory. The results were used to optimise cluster performance, and consequently increase cluster throughput by up to 10%.

  2. A comparative study of marriage in honey bees optimisation (MBO ...

    African Journals Online (AJOL)

    2012-02-15

    Feb 15, 2012 ... complicate water management decision-making. ... evolutionary algorithms, such as the genetic algorithm (GA), ant colony optimisation for continuous ... biological properties. ... and proposed a new algorithm,called the 'artificial bee colony' ... as a set of transitions in a state–space (the environment), where.

  3. Smart optimisation and sensitivity analysis in water distribution systems

    CSIR Research Space (South Africa)

    Page, Philip R

    2015-12-01

    Full Text Available stream_source_info Page_16028_2015.pdf.txt stream_content_type text/plain stream_size 1806 Content-Encoding ISO-8859-1 stream_name Page_16028_2015.pdf.txt Content-Type text/plain; charset=ISO-8859-1 SMART OPTIMISATION...

  4. Computational optimisation of targeted DNA sequencing for cancer detection

    DEFF Research Database (Denmark)

    Martinez, Pierre; McGranahan, Nicholas; Birkbak, Nicolai Juul

    2013-01-01

    circulating tumour DNA (ctDNA) might represent a non-invasive method to detect mutations in patients, facilitating early detection. In this article, we define reduced gene panels from publicly available datasets as a first step to assess and optimise the potential of targeted ctDNA scans for early tumour...

  5. Application of Surpac and Whittle Software in Open Pit Optimisation ...

    African Journals Online (AJOL)

    Michael

    2015-06-01

    Jun 1, 2015 ... Optimisation and Design”, Ghana Mining Journal, Vol. 15, No. 1, pp. 35 - 43. Abstract ... reduction in metal price in the market. The work involved in open .... also aided in viewing the model in graphics. A constraint is a logical ...

  6. Optimising Microbial Growth with a Bench-Top Bioreactor

    Science.gov (United States)

    Baker, A. M. R.; Borin, S. L.; Chooi, K. P.; Huang, S. S.; Newgas, A. J. S.; Sodagar, D.; Ziegler, C. A.; Chan, G. H. T.; Walsh, K. A. P.

    2006-01-01

    The effects of impeller size, agitation and aeration on the rate of yeast growth were investigated using bench-top bioreactors. This exercise, carried out over a six-month period, served as an effective demonstration of the importance of different operating parameters on cell growth and provided a means of determining the optimisation conditions…

  7. Deterministic and robust optimisation strategies for metal forming proceesses

    NARCIS (Netherlands)

    Bonte, M.H.A.; Boogaard, van den A.H.; Huetink, J.

    2007-01-01

    Product improvement and cost reduction have always been important goals in the metal forming industry. The rise of Finite Element simulations for metal forming processes has contributed to these goals in a major way. More recently, coupling FEM simulations to mathematical optimisation techniques has

  8. Optimising a fall out dust monitoring sampling programme at a ...

    African Journals Online (AJOL)

    GREG

    The aim of this study at the specific cement manufacturing plant and open cast mine was ... Key words: Fall out dust monitoring, cement plant, optimising, air pollution sampling, ..... meters as this is in line with the height of a typical fall out dust.

  9. Optimisation of searches for Supersymmetry with the ATLAS detector

    Energy Technology Data Exchange (ETDEWEB)

    Zvolsky, Milan

    2012-01-15

    The ATLAS experiment is one of the four large experiments at the Large Hadron Collider which is specifically designed to search for the Higgs boson and physics beyond the Standard Model. The aim of this thesis is the optimisation of searches for Supersymmetry in decays with two leptons and missing transverse energy in the final state. Two different optimisation studies have been performed for two important analysis aspects: The final signal region selection and the choice of the trigger selection. In the first part of the analysis, a cut-based optimisation of signal regions is performed, maximising the signal for a minimal background contamination. By this, the signal yield can in parts be more than doubled. The second approach is to introduce di-lepton triggers which allow to lower the lepton transverse momentum threshold, thus enhancing the number of selected signal events significantly. The signal region optimisation was considered for the choice of the final event selection in the ATLAS di-lepton analyses. The trigger study contributed to the incorporation of di-lepton triggers to the ATLAS trigger menu. (orig.)

  10. Optimised prefactored compact schemes for linear wave propagation phenomena

    Science.gov (United States)

    Rona, A.; Spisso, I.; Hall, E.; Bernardini, M.; Pirozzoli, S.

    2017-01-01

    A family of space- and time-optimised prefactored compact schemes are developed that minimise the computational cost for given levels of numerical error in wave propagation phenomena, with special reference to aerodynamic sound. This work extends the approach of Pirozzoli [1] to the MacCormack type prefactored compact high-order schemes developed by Hixon [2], in which their shorter Padé stencil from the prefactorisation leads to a simpler enforcement of numerical boundary conditions. An explicit low-storage multi-step Runge-Kutta integration advances the states in time. Theoretical predictions for spatial and temporal error bounds are derived for the cost-optimised schemes and compared against benchmark schemes of current use in computational aeroacoustic applications in terms of computational cost for a given relative numerical error value. One- and two-dimensional test cases are presented to examine the effectiveness of the cost-optimised schemes for practical flow computations. An effectiveness up to about 50% higher than the standard schemes is verified for the linear one-dimensional advection solver, which is a popular baseline solver kernel for computational physics problems. A substantial error reduction for a given cost is also obtained in the more complex case of a two-dimensional acoustic pulse propagation, provided the optimised schemes are made to operate close to their nominal design points.

  11. Using break quantities for tactical optimisation in multistage distribution systems

    NARCIS (Netherlands)

    M.J. Kleijn (Marcel); R. Dekker (Rommert)

    1997-01-01

    textabstractIn this chapter we discuss a tactical optimisation problem that arises in a multistage distribution system where customer orders can be delivered from any stockpoint. A simple rule to allocate orders to locations is a break quantity rule, which routes large orders to higher-stage stockpo

  12. Wear/comfort Pareto optimisation of bogie suspension

    Science.gov (United States)

    Milad Mousavi Bideleh, Seyed; Berbyuk, Viktor; Persson, Rickard

    2016-08-01

    Pareto optimisation of bogie suspension components is considered for a 50 degrees of freedom railway vehicle model to reduce wheel/rail contact wear and improve passenger ride comfort. Several operational scenarios including tracks with different curve radii ranging from very small radii up to straight tracks are considered for the analysis. In each case, the maximum admissible speed is applied to the vehicle. Design parameters are categorised into two levels and the wear/comfort Pareto optimisation is accordingly accomplished in a multistep manner to improve the computational efficiency. The genetic algorithm (GA) is employed to perform the multi-objective optimisation. Two suspension system configurations are considered, a symmetric and an asymmetric in which the primary or secondary suspension elements on the right- and left-hand sides of the vehicle are not the same. It is shown that the vehicle performance on curves can be significantly improved using the asymmetric suspension configuration. The Pareto-optimised values of the design parameters achieved here guarantee wear reduction and comfort improvement for railway vehicles and can also be utilised in developing the reference vehicle models for design of bogie active suspension systems.

  13. Adaptive optimisation of a generalised beam shaping system

    DEFF Research Database (Denmark)

    Kenny, F.; Choi, F. S.; Glückstad, Jesper

    2015-01-01

    filter were generated by the SLM. This provided extra flexibility and control over the parameters of the system including the phase step magnitude, shape, radius and position of the filter. A feedback method for the on-line optimisation of these properties was also developed. Using feedback from images...

  14. Multi-disciplinary design optimisation via dashboard portals

    NARCIS (Netherlands)

    Uijtenhaak, T.; Coenders, J.L.

    2012-01-01

    This paper will present the opportunities a dashboard-based system provides to gather information on alternatives and display this in such a way that it will help the user making decisions by making use of multi-disciplinary optimisation (MDO) technology. The multi-disciplinary set up of the program

  15. A metamodel based optimisation algorithm for metal forming processes

    NARCIS (Netherlands)

    Bonte, M.H.A.; Boogaard, van den A.H.; Huetink, J.; Banabic, Dorel

    2007-01-01

    Cost saving and product improvement have always been important goals in the metal forming industry. To achieve these goals, metal forming processes need to be optimised. During the last decades, simulation software based on the Finite Element Method (FEM) has significantly contributed to designing f

  16. Optimised cantilever biosensor with piezoresistive read-out

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Thaysen, J.; Hansen, Ole

    2003-01-01

    We present a cantilever-based biochemical sensor with piezoresistive read-out which has been optimised for measuring surface stress. The resistors and the electrical wiring on the chip are encapsulated in low-pressure chemical vapor deposition (LPCVD) silicon nitride, so that the chip is well sui...

  17. Optimisation of selective breeding program for Nile tilapia (Oreochromis niloticus)

    NARCIS (Netherlands)

    Trong, T.Q.

    2013-01-01

      The aim of this thesis was to optimise the selective breeding program for Nile tilapia in the Mekong Delta region of Vietnam. Two breeding schemes, the “classic” BLUP scheme following the GIFT method (with pair mating) and a rotational mating scheme with own performance selection

  18. SINGLE FIXED CRANE OPTIMISATION WITHIN A DISTRIBUTION CENTRE

    Directory of Open Access Journals (Sweden)

    J. Matthews

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: This paper considersthe optimisation of the movement of a fixed crane operating in a single aisle of a distribution centre. The crane must move pallets in inventory between docking bays, storage locations, and picking lines. Both a static and a dynamic approach to the problem are presented. The optimisation is performed by means of tabu search, ant colony metaheuristics,and hybrids of these two methods. All these solution approaches were tested on real life data obtained from an operational distribution centre. Results indicate that the hybrid methods outperform the other approaches.

    AFRIKAANSE OPSOMMING: Die optimisering van die beweging van 'n vaste hyskraan in 'n enkele gang van 'n distribusiesentrum word in hierdie artikel beskou. Die hyskraan moet pallette vervoer tussen dokhokke, stoorposisies, en opmaaklyne. Beide 'n statiese en 'n dinamiese benadering tot die probleem word aangebied. Die optimisering word gedoen met behulp van tabu-soektogte, mierkolonieoptimisering,en hibriede van hierdie twee metodes. Al die oplossingsbenaderings is getoets met werklike data wat van 'n operasionele distribusiesentrum verkry is. Die resultate toon aan dat die hibriedmetodes die beste oplossings lewer.

  19. Hierarchical optimisation on scissor seat suspension characteristic and structure

    Science.gov (United States)

    Wang, Chunlei; Zhang, Xinjie; Guo, Konghui; Lv, Jiming; Yang, Yi

    2016-11-01

    Scissor seat suspension has been applied widely to attenuate the cab vibrations of commercial vehicles, while its design generally needs a trade-off between the seat acceleration and suspension travel, which creates a typical optimisation issue. A complexity for this issue is that the optimal dynamics parameters are not easy to approach solutions fast and unequivocally. Hence, the hierarchical optimisation on scissor seat suspension characteristic and structure is proposed, providing a top-down methodology with the globally optimal and fast convergent solutions to compromise these design contradictions. In details, a characteristic-oriented non-parametric dynamics model of the scissor seat suspension is formulated firstly via databases, describing its vertical dynamics accurately. Then, the ideal vertical stiffness-damping characteristic is cascaded via the characteristic-oriented model, and the structure parameters are optimised in accordance with a structure-oriented multi-body dynamics model of the scissor seat suspension. Eventually, the seat effective amplitude transmissibility factor, suspension travel and the CPU time for solving are evaluated. The results show the seat suspension performance and convergent speed of the globally optimal solutions are improved well. Hence, the proposed hierarchical optimisation methodology regarding characteristic and structure of the scissor seat suspension is promising for its virtual development.

  20. Multi-disciplinary design optimisation via dashboard portals

    NARCIS (Netherlands)

    Uijtenhaak, T.; Coenders, J.L.

    2012-01-01

    This paper will present the opportunities a dashboard-based system provides to gather information on alternatives and display this in such a way that it will help the user making decisions by making use of multi-disciplinary optimisation (MDO) technology. The multi-disciplinary set up of the program

  1. Analysing the performance of dynamic multi-objective optimisation algorithms

    CSIR Research Space (South Africa)

    Helbig, M

    2013-06-01

    Full Text Available Congress on Evolutionary Computation, 20-23 June 2013, Cancún, México Analysing the Performance of Dynamic Multi-objective Optimisation Algorithms Marde Helbig CSIR: Meraka Institute, Brummeria, South Africa; and University of Pretoria Computer...

  2. Self-organising sensor web using cell-fate optimisation

    CSIR Research Space (South Africa)

    Van Zyl, TL

    2009-07-01

    Full Text Available may be doing so both dynamically and stochastically. When presented by a dynamic and stochastic changing environment, such as a sensor resource unexpectedly going down, a self-adaptive system should exhibit robustness. Cell-fate optimisation and signal...

  3. Hygrothermal optimisation of museum storage spaces

    DEFF Research Database (Denmark)

    Janssen, Hans; Christensen, Jørgen Erik

    2013-01-01

    Despite the large economic and ecologic costs, museum storage spaces are often equipped with extensive air conditioning, to provide the desired stable interior climate. The new “passive conditioning” paradigm aims at resolving these costs: a high-hygrothermal-inertia building with a high-hygrothermal-resistance...... envelope is to satisfactorily stabilise that interior climate, with no need for mechanical air conditioning hence.This paper first studies the reliability of full passive conditioning for museum storage spaces. It is shown to be an illusion, since it usually results in excessive interior humidities....... Auxiliary dehumidification is thus required to provide good conservation conditions, and it is secondly investigated how the dehumidification load can be diminished. The study reveals the crucial impact of air tightness, while thermal insulation only has a minor influence.To further reduce the economic...

  4. A structural study for the optimisation of functional motifs encoded in protein sequences

    Directory of Open Access Journals (Sweden)

    Helmer-Citterich Manuela

    2004-04-01

    Full Text Available Abstract Background A large number of PROSITE patterns select false positives and/or miss known true positives. It is possible that – at least in some cases – the weak specificity and/or sensitivity of a pattern is due to the fact that one, or maybe more, functional and/or structural key residues are not represented in the pattern. Multiple sequence alignments are commonly used to build functional sequence patterns. If residues structurally conserved in proteins sharing a function cannot be aligned in a multiple sequence alignment, they are likely to be missed in a standard pattern construction procedure. Results Here we present a new procedure aimed at improving the sensitivity and/ or specificity of poorly-performing patterns. The procedure can be summarised as follows: 1. residues structurally conserved in different proteins, that are true positives for a pattern, are identified by means of a computational technique and by visual inspection. 2. the sequence positions of the structurally conserved residues falling outside the pattern are used to build extended sequence patterns. 3. the extended patterns are optimised on the SWISS-PROT database for their sensitivity and specificity. The method was applied to eight PROSITE patterns. Whenever structurally conserved residues are found in the surface region close to the pattern (seven out of eight cases, the addition of information inferred from structural analysis is shown to improve pattern selectivity and in some cases selectivity and sensitivity as well. In some of the cases considered the procedure allowed the identification of functionally interesting residues, whose biological role is also discussed. Conclusion Our method can be applied to any type of functional motif or pattern (not only PROSITE ones which is not able to select all and only the true positive hits and for which at least two true positive structures are available. The computational technique for the identification of

  5. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  6. Carbohydrate Loading.

    Science.gov (United States)

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  7. Load sensor

    NARCIS (Netherlands)

    Van den Ende, D.; Almeida, P.M.R.; Dingemans, T.J.; Van der Zwaag, S.

    2007-01-01

    The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder for

  8. Carbohydrate Loading.

    Science.gov (United States)

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  9. A methodological approach to the design of optimising control strategies for sewer systems

    DEFF Research Database (Denmark)

    Mollerup, Ane Loft; Mikkelsen, Peter Steen; Sin, Gürkan

    2016-01-01

    This study focuses on designing an optimisation based control for sewer system in a methodological way and linking itto a regulatory control. Optimisation based design is found to depend on proper choice of a model, formulation of objective function and tuning of optimisation parameters. Accordin......This study focuses on designing an optimisation based control for sewer system in a methodological way and linking itto a regulatory control. Optimisation based design is found to depend on proper choice of a model, formulation of objective function and tuning of optimisation parameters...... control; a rule based expert system. On the other hand, compared with a regulatory control technique designed earlier in Mollerup et al. (2015), the optimisation showed similar performance with respect to minimising overflow volume. Hence for operation of small sewer systems, regulatory control strategies...... can offer promising potential and should be considered along more advanced strategies when identifying novel solutions....

  10. Mesh dependence in PDE-constrained optimisation an application in tidal turbine array layouts

    CERN Document Server

    Schwedes, Tobias; Funke, Simon W; Piggott, Matthew D

    2017-01-01

    This book provides an introduction to PDE-constrained optimisation using finite elements and the adjoint approach. The practical impact of the mathematical insights presented here are demonstrated using the realistic scenario of the optimal placement of marine power turbines, thereby illustrating the real-world relevance of best-practice Hilbert space aware approaches to PDE-constrained optimisation problems. Many optimisation problems that arise in a real-world context are constrained by partial differential equations (PDEs). That is, the system whose configuration is to be optimised follows physical laws given by PDEs. This book describes general Hilbert space formulations of optimisation algorithms, thereby facilitating optimisations whose controls are functions of space. It demonstrates the importance of methods that respect the Hilbert space structure of the problem by analysing the mathematical drawbacks of failing to do so. The approaches considered are illustrated using the optimisation problem arisin...

  11. IoT-based electricity load optimisation: initial results of a monitor and control system

    CSIR Research Space (South Africa)

    Smith, Andrew C

    2012-11-01

    Full Text Available The demand for electrical energy is increasing globally. Both the average as well as the anticipated peak demand must be considered by the supplier when designing an electrical supply. We present an Internet of Things – based system, and a concept...

  12. Class-modelling in food analytical chemistry: Development, sampling, optimisation and validation issues - A tutorial.

    Science.gov (United States)

    Oliveri, Paolo

    2017-08-22

    Qualitative data modelling is a fundamental branch of pattern recognition, with many applications in analytical chemistry, and embraces two main families: discriminant and class-modelling methods. The first strategy is appropriate when at least two classes are meaningfully defined in the problem under study, while the second strategy is the right choice when the focus is on a single class. For this reason, class-modelling methods are also referred to as one-class classifiers. Although, in the food analytical field, most of the issues would be properly addressed by class-modelling strategies, the use of such techniques is rather limited and, in many cases, discriminant methods are forcedly used for one-class problems, introducing a bias in the outcomes. Key aspects related to the development, optimisation and validation of suitable class models for the characterisation of food products are critically analysed and discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. A Review of the Optimisation of Photopolymer Materials for Holographic Data Storage

    Directory of Open Access Journals (Sweden)

    Jinxin Guo

    2012-01-01

    Full Text Available Photopolymers are very interesting as optically sensitive recording media due to the fact that they are inexpensive, self-processing materials with the ability to capture low-loss, high-fidelity volume recordings of 3D illuminating patterns. We have prepared this paper in part in order to enable the recognition of outstanding issues, which limit in particular the data storage capacity in holographic data storage media. In an attempt to further develop the data storage capacity and quality of the information stored, that is, the material sensitivity and resolution, a deeper understanding of such materials in order to improve them has become ever more crucial. In this paper a brief review of the optimisation of photopolymer materials for holographic data storage (HDS applications is described. The key contributions of each work examined and many of the suggestions made for the improvement of the different photopolymer material discussed are presented.

  14. Allocation of Power Meters for Online Load Distribution Estimation in Smart Grids

    DEFF Research Database (Denmark)

    Kouzelis, Konstantinos; Diaz de Cerio Mendaza, Iker; Bak-Jensen, Birgitte

    2015-01-01

    observability of the load distribution in their grid throughout the day. This paper investigates the possibility of improving the observability by allocating a minimum number of additional online operated power meters in the distribution grid. This allocation, driven by optimisation, clustering, and forecasting...

  15. Experimental study on the structural and mooring loads of the WEPTOS Wave Energy Converter

    DEFF Research Database (Denmark)

    Pecher, Arthur Francois Serge; Kofoed, Jens Peter

    This report presents the results of an experimental study that was performed on small scale model that was a replication of the full-scale Weptos WEC intended for DanWEC. During these tests, after optimising the mooring solution, various loads were measured that occur in the structure and mooring...

  16. A novel microwave synthesis of calcium hydroxyapatite. Optimisation and investigation of a microwave assisted reaction route

    CERN Document Server

    Zawahreh, Y

    2001-01-01

    Hydroxyapatite is a bioactive calcium phosphate used in non-load bearing applications, such as space-filling in maxillofacial reconstruction. As a coating, hydroxyapatite is used on load-bearing orthopaedic metal prostheses to improve fixation and/or biocompatibility. Conventional synthesis processes for the production of hydroxyapatite are time-consuming and labour-intensive. Microwave irradiation was investigated as a means to enhance the synthesis reaction using calcium hydroxide (Ca(OH) sub 2) and orthophosphoric acid (H sub 3 PO sub 4) as reactants. An initial set of reactions indicated the feasibility of the microwave synthesis route. Optimisation reactions were then performed followed by investigation sets of reactions. Parameters such as microwave power, irradiation time, and reactant concentrations were varied. Using 0.5M Ca(OH) sub 2 and 0.3M H sub 3 PO sub 4 , a phase-pure hydroxyapatite powder with a stoichiometric molar Ca/P ratio of 1.67 was produced in 60 seconds at 450W and 2.45GHz. The microw...

  17. Optimisation of post-weld heat treatment — A simple, practical method

    Indian Academy of Sciences (India)

    P Rodriguez; S K Ray; A K Bhaduri

    2003-06-01

    The authors have evolved an empirical method for characterizing resistance to ductile fracture using two parameters $\\Gamma _f$ and $\\eta_f$ that can be determined from tensile test data of smooth cylindrical specimens. This method stipulates that the post-necking regime during tensile deformation is dominated by microvoid growth and coalescence processes, and therefore the energy absorbed in this regime can be used to estimate the resistance of the necked region to ductile fracture. The test procedure employed is simple and does not require gauge-length extensometry, a distinct advantage at non-ambient temperatures. The tests are carried out in a screw-driven machine at a constant crosshead speed, with online computerized acquisition of load-time data; it is also necessary to have a prior precise calibration for the (nonlinear) elastic deformation of the load train. The method of computing $\\Gamma_f$ and $\\eta_f$ , from tensile data is described, and its engineering application demonstrated by characterizing the effect of ageing of two dissimilar metal welds, namely Alloy 800/2.25Cr–1Mo steel and Alloy 800/9Cr–1Mo steel. From these results, it has been established that this procedure of estimating the ductile fracture toughness from tensile tests can be used as a simple, practical method for optimisation of post-weld heat treatment of weld joints.

  18. Optimising steel production schedules via a hierarchical genetic algorithm

    Directory of Open Access Journals (Sweden)

    Worapradya, Kiatkajohn

    2014-08-01

    Full Text Available This paper presents an effective scheduling in a steel-making continuous casting (SCC plant. The main contribution of this paper is the formulation of a new optimisation model that more closely represents real-world situations, and a hierarchical genetic algorithm (HGA tailored particularly for searching for an optimal SCC schedule. The optimisation model is developed by integrating two main planning phases of traditional scheduling: (1 planning cast sequence, and (2 scheduling of steel-making and timing of all jobs. A novel procedure is given for genetic algorithm (GA chromosome coding that maps Gantt chart and hierarchical chromosomes. The performance of the proposed methodology is illustrated and compared with a two-phase traditional scheduling and a standard GA toolbox. Both qualitative and quantitative performance measures are investigated.

  19. Optimisation of metal charge material for electric arc furnace

    Directory of Open Access Journals (Sweden)

    T. Lis

    2011-10-01

    Full Text Available The analysis of the changes in the crude steel production volumes implies gradual increase of production since the mid 20th century. This tendency has been slightly hampered by the economic depression. At the same time, the market requirements enforce improvement of the quality of the products manufactured on simultaneous minimisation of the production costs. One of the tools applied to solve these problems is mathematical optimisation. The author of this paper has presented an example of application of the multi-criteria optimisation method to improvement of efficiency of steel smelting in an electric arc furnace (EAF through appropriate choice of the charge scrap. A measurable effect of applying such a methodology of choosing the metal charge is the ability to reduce the unit cost of steel smelting.

  20. Compressed Sensing with Nonlinear Observations and Related Nonlinear Optimisation Problems

    CERN Document Server

    Blumensath, Thomas

    2012-01-01

    Non-convex constraints have recently proven a valuable tool in many optimisation problems. In particular sparsity constraints have had a significant impact on sampling theory, where they are used in Compressed Sensing and allow structured signals to be sampled far below the rate traditionally prescribed. Nearly all of the theory developed for Compressed Sensing signal recovery assumes that samples are taken using linear measurements. In this paper we instead address the Compressed Sensing recovery problem in a setting where the observations are non-linear. We show that, under conditions similar to those required in the linear setting, the Iterative Hard Thresholding algorithm can be used to accurately recover sparse or structured signals from few non-linear observations. Similar ideas can also be developed in a more general non-linear optimisation framework. In the second part of this paper we therefore present related result that show how this can be done under sparsity and union of subspaces constraints, wh...

  1. Optimisation of VSC-HVDC Transmission for Wind Power Plants

    DEFF Research Database (Denmark)

    Silva, Rodrigo Da

    Connection of Wind Power Plants (WPP), typically oshore, using VSCHVDC transmission is an emerging solution with many benefits compared to the traditional AC solution, especially concerning the impact on control architecture of the wind farms and the grid. The VSC-HVDC solution is likely to meet...... more stringent grid codes than a conventional AC transmission connection. The purpose of this project is to analyse how HVDC solution, considering the voltage-source converter based technology, for grid connection of large wind power plants can be designed and optimised. By optimisation, the project...... the requirements established by the operators in the multiterminal VSC-HVDC transmission system. Moreover, the possibility in minimising the overall transmission losses can be a solution for small grids and the minimisation in the dispatch error is a new solution for power deliver maximisation. The second study...

  2. Comparing and Optimising Parallel Haskell Implementations for Multicore Machines

    DEFF Research Database (Denmark)

    Berthold, Jost; Marlow, Simon; Hammond, Kevin

    2009-01-01

    by our testing: for example, we implemented a work-stealing approach to task allocation. Our optimisations improved the performance of the shared-heap GpH implementation by as much as 30% on eight cores. Secondly, the shared heap approach is, rather surprisingly, not superior to a distributed heap......H implementation investigated here uses a physically-shared heap, which should be well-suited to multicore architectures. In contrast, the Eden implementation adopts an approach that has been designed for use on distributed-memory parallel machines: a system of multiple, independent heaps (one per core......), with inter-core communication handled by message-passing rather than through shared heap cells. We report two main results. Firstly, we report on the effect of a number of optimisations that we applied to the shared-memory GpH implementation in order to address some performance issues that were revealed...

  3. Optimising stroke volume and oxygen delivery in abdominal aortic surgery

    DEFF Research Database (Denmark)

    Bisgaard, J; Gilsaa, T; Rønholm, E

    2012-01-01

    group, stroke volume was optimised by 250 ml colloid boluses intraoperatively and for the first 6 h post-operatively. The optimisation aimed at an oxygen delivery of 600 ml/min/m(2) in the post-operative period. Haemodynamic data were collected at pre-defined time points, including baseline......BACKGROUND: Post-operative complications after open elective abdominal aortic surgery are common, and individualised goal-directed therapy may improve outcome in high-risk surgery. We hypothesised that individualised goal-directed therapy, targeting stroke volume and oxygen delivery, can reduce......, intraoperatively and post-operatively. Patients were followed up for 30 days. RESULTS: Stroke volume index and oxygen delivery index were both higher in the post-operative period in the intervention group. In this group, 27 of 32 achieved the post-operative oxygen delivery index target vs. 18 of 32 in the control...

  4. Eyes Wide Open - Optimising Cosmological Surveys in a Crowded Market

    CERN Document Server

    Bassett, B A

    2004-01-01

    Optimising the major next-generation cosmological surveys (such as SNAP, KAOS etc...) is a key problem given our ignorance of the physics underlying cosmic acceleration and the plethora of surveys planned. We propose a Bayesian design framework which (1) maximises the discrimination power of a survey without assuming any underlying dark energy model, (2) finds the best niche survey geometry given current data and future competing experiments, (3) maximises the cross-section for serendipitous discoveries and (4) can be adapted to answer specific questions (such as `is dark energy dynamical?'). Integrated Parameter Space Optimisation (IPSO) is a design framework that integrates projected parameter errors over an entire dark energy parameter space and then extremises a figure of merit (such as Shannon entropy gain wich we show is stable to off-diagonal covariance matrix perturbations) as a function of survey parameters using analytical, grid or MCMC techniques. IPSO is thus a flexible, model-independent and scal...

  5. Biomass supply chain optimisation for Organosolv-based biorefineries.

    Science.gov (United States)

    Giarola, Sara; Patel, Mayank; Shah, Nilay

    2014-05-01

    This work aims at providing a Mixed Integer Linear Programming modelling framework to help define planning strategies for the development of sustainable biorefineries. The up-scaling of an Organosolv biorefinery was addressed via optimisation of the whole system economics. Three real world case studies were addressed to show the high-level flexibility and wide applicability of the tool to model different biomass typologies (i.e. forest fellings, cereal residues and energy crops) and supply strategies. Model outcomes have revealed how supply chain optimisation techniques could help shed light on the development of sustainable biorefineries. Feedstock quality, quantity, temporal and geographical availability are crucial to determine biorefinery location and the cost-efficient way to supply the feedstock to the plant. Storage costs are relevant for biorefineries based on cereal stubble, while wood supply chains present dominant pretreatment operations costs.

  6. Optimised Calibration Method for Six-Port Junction

    Institute of Scientific and Technical Information of China (English)

    XIONG Xiang-zheng; LIAO Cheng; XIAO Hua-qing

    2008-01-01

    A dual-tone technique is used to produce multi-samples in optimising calibration of six-port junction. More accurate results are achieved by using the least-square method and excluding those samples which may cause bigger errors. A 0.80 1.10 GHz microwave integrated circuit (MIC) six-port reflectometer is constructed. Nine test samples are used in the measurement. With Engens calibration procedure, the difference between the HP8510 and the six-port reflectrometer is in the order of 0.20 dB/1.5° for most cases, above 0.50 dB/5.0° at boundary frequency . With the optimised method, the difference is less than 0.10 dB/1.0° for most cases, and the biggest error is 0.42 dB/2.1° for boundary frequencies.

  7. An Experimental Approach for Optimising Mobile Agent Migrations

    CERN Document Server

    Gavalas, Damianos

    2010-01-01

    The field of mobile agent (MA) technology has been intensively researched during the past few years, resulting in the phenomenal proliferation of available MA platforms, all sharing several common design characteristics. Research projects have mainly focused on identifying applications where the employment of MAs is preferable compared to centralised or alternative distributed computing models. Very little work has been made on examining how MA platforms design can be optimised so as the network traffic and latency associated with MA transfers are minimised. The work presented in this paper addresses these issues by investigating the effect of several optimisation ideas applied on our MA platform prototype. Furthermore, we discuss the results of a set of timing experiments that offers a better understanding of the agent migration process and recommend new techniques for reducing MA transfers delay.

  8. Topology Optimised Broadband Photonic Crystal Y-Splitter

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Frandsen, Lars Hagedorn; Harpøth, Anders

    2005-01-01

    A planar photonic crystal waveguide Y-splitter that exhibits large-bandwidth low-loss 3 dB splitting for TE-polarised light has been fabricated in silicon-on-insulator material. The high performance is achieved by utilising topology optimisation to design the Y-junction and by using topology...... optimised low-loss 60° bends. The average excess loss of the entire component is found to be 0.44±0.29 dB for a 100 nm bandwidth, and the excess loss due to the Y-junction is found to be 0.34±0.30 dB in a 175 nm bandwidth....

  9. Development and optimisation of electrodematerials in solid oxide fuel cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Solid oxide fuel cell (SOFC) is an all solid electrochemical device to convert fuels such as hydrogen and natural gas to electricity with high efficiency and very low greenhouse gas emission compared to traditional thermal power generation plants. Moreover, the reliability and efficiency of SOFC is critically dependent on the performance and stability of its components including anode, cathode and electrolyte. This in turn is largely dependent on the material selection and the fabrication processes. In this paper, specific examples are given to demonstrate strategy and process in the development and optimisation of electrode materials such as Ni/Y2O3-ZrO2 cermet anodes and (LaSr)MnO3 based cathodes. The results also demonstrate the importance of fabrication processes and that the understanding of the electrode process plays a very important role in the optimisation process of electrode materials.

  10. Computed tomography dose optimisation in cystic fibrosis: A review.

    LENUS (Irish Health Repository)

    Ferris, Helena

    2016-04-28

    Cystic fibrosis (CF) is the most common autosomal recessive disease of the Caucasian population worldwide, with respiratory disease remaining the most relevant source of morbidity and mortality. Computed tomography (CT) is frequently used for monitoring disease complications and progression. Over the last fifteen years there has been a six-fold increase in the use of CT, which has lead to a growing concern in relation to cumulative radiation exposure. The challenge to the medical profession is to identify dose reduction strategies that meet acceptable image quality, but fulfil the requirements of a diagnostic quality CT. Dose-optimisation, particularly in CT, is essential as it reduces the chances of patients receiving cumulative radiation doses in excess of 100 mSv, a dose deemed significant by the United Nations Scientific Committee on the Effects of Atomic Radiation. This review article explores the current trends in imaging in CF with particular emphasis on new developments in dose optimisation.

  11. Alginate microencapsulated hepatocytes optimised for transplantation in acute liver failure.

    Directory of Open Access Journals (Sweden)

    Suttiruk Jitraruch

    Full Text Available BACKGROUND AND AIM: Intraperitoneal transplantation of alginate-microencapsulated human hepatocytes is an attractive option for the management of acute liver failure (ALF providing short-term support to allow native liver regeneration. The main aim of this study was to establish an optimised protocol for production of alginate-encapsulated human hepatocytes and evaluate their suitability for clinical use. METHODS: Human hepatocyte microbeads (HMBs were prepared using sterile GMP grade materials. We determined physical stability, cell viability, and hepatocyte metabolic function of HMBs using different polymerisation times and cell densities. The immune activation of peripheral blood mononuclear cells (PBMCs after co-culture with HMBs was studied. Rats with ALF induced by galactosamine were transplanted intraperitoneally with rat hepatocyte microbeads (RMBs produced using a similar optimised protocol. Survival rate and biochemical profiles were determined. Retrieved microbeads were evaluated for morphology and functionality. RESULTS: The optimised HMBs were of uniform size (583.5±3.3 µm and mechanically stable using 15 min polymerisation time compared to 10 min and 20 min (p<0.001. 3D confocal microscopy images demonstrated that hepatocytes with similar cell viability were evenly distributed within HMBs. Cell density of 3.5×10(6 cells/ml provided the highest viability. HMBs incubated in human ascitic fluid showed better cell viability and function than controls. There was no significant activation of PBMCs co-cultured with empty or hepatocyte microbeads, compared to PBMCs alone. Intraperitoneal transplantation of RMBs was safe and significantly improved the severity of liver damage compared to control groups (empty microbeads and medium alone; p<0.01. Retrieved RMBs were intact and free of immune cell adherence and contained viable hepatocytes with preserved function. CONCLUSION: An optimised protocol to produce GMP grade alginate

  12. Integrated planning tool for optimisation in municipal home care

    OpenAIRE

    Røhne, Mette; Sandåker, Torjus; Ausen, Dag; Grut, Lisbet

    2016-01-01

    Purpose: The objective is to improve collaboration and enhance quality of care services in municipal, home care services by implementing and developing an integrated planning tool making use of optimisation technology for better decision support. The project will through piloting and action based research establish knowledge on change in work processes to improve collaboration and efficiency. Context: A planning tool called Spider has been piloted in home care in Horten municipality since 201...

  13. Topology Optimisation for Energy Management in Underwater Sensor Networks

    Science.gov (United States)

    2015-01-01

    International Journal of Control, 2015 http://dx.doi.org/10.1080/00207179.2015.1017006 Topology optimisation for energy management in underwater...State University, University Park , PA 16802-1412, USA; bNaval Undersea Warfare Center, Newport, RI 02841-1708, USA and Department of Mechanical & Nuclear...Engineering, Pennsylvania State University, University Park , PA 16802-1412, USA; cUnited Technology Research Center, Cork, Ireland (Received 28

  14. Optimising automation of a manual enzyme-linked immunosorbent assay

    OpenAIRE

    Corena de Beer; Monika Esser; Wolfgang Preiser

    2011-01-01

    Objective: Enzyme-linked immunosorbent assays (ELISAs) are widely used to quantify immunoglobulin levels induced by infection or vaccination. Compared to conventional manual assays, automated ELISA systems offer more accurate and reproducible results, faster turnaround times and cost effectiveness due to the use of multianalyte reagents.Design: The VaccZyme™ Human Anti-Haemophilus influenzae type B (Hib) kit (MK016) from The Binding Site Company was optimised to be used on an automated BioRad...

  15. Optimisation of brain SPET and portability of normal databases

    Energy Technology Data Exchange (ETDEWEB)

    Barnden, Leighton R.; Behin-Ain, Setayesh; Goble, Elizabeth A. [The Queen Elizabeth Hospital, Adelaide (Australia); Hatton, Rochelle L.; Hutton, Brian F. [Westmead Hospital, Sydney (Australia)

    2004-03-01

    Use of a normal database in quantitative regional analysis of brain single-photon emission tomography (SPET) facilitates the detection of functional defects in individual or group studies by accounting for inter-subject variability. Different reconstruction methods and suboptimal attenuation and scatter correction methods can introduce additional variance that will adversely affect such analysis. Similarly, processing differences across different instruments and/or institutions may invalidate the use of external normal databases. The object of this study was to minimise additional variance by comparing reconstructions of a physical phantom with its numerical template so as to optimise processing parameters. Age- and gender-matched normal scans acquired on two different systems were compared using SPM99 after processing with both standard and optimised parameters. For three SPET systems we have optimised parameters for attenuation correction, lower window scatter subtraction, reconstructed pixel size and fanbeam focal length for both filtered back-projection (FBP) and iterative (OSEM) reconstruction. Both attenuation and scatter correction improved accuracy for all systems. For single-iteration Chang attenuation correction the optimum attenuation coefficient (mu) was 0.45-0.85 of the narrow beam value (Nmu) before, and 0.75-0.85 Nmu after, scatter subtraction. For accurately modelled OSEM attenuation correction, optimum mu was 0.6-0.9 Nmu before and 0.9-1.1 Nmu after scatter subtraction. FBP appeared to change in-plane voxel dimensions by about 2% and this was confirmed by line phantom measurements. Improvement in accuracy with scatter subtraction was most marked for the highest spatial resolution system. Optimised processing reduced but did not remove highly significant regional differences between normal databases acquired on two different SPET systems. (orig.)

  16. Geometrical optimisation of a biochip microchannel fluidic separator.

    Science.gov (United States)

    Xue, Xiangdong; Patel, Mayur K; Bailey, Chris; Desmulliez, Marc P Y

    2012-01-01

    This article reports on the geometric optimisation of a T-shaped biochip microchannel fluidic separator aiming to maximise the separation efficiency of plasma from blood through the improvement of the unbalanced separation performance among different channel bifurcations. For this purpose, an algebraic analysis is firstly implemented to identify the key parameters affecting fluid separation. A numerical optimisation is then carried out to search the key parameters for improved separation performance of the biochip. Three parameters, the interval length between bifurcations, the main channel length from the outlet to the bifurcation region and the side channel geometry, are identified as the key characteristic sizes and defined as optimisation variables. A balanced flow rate ratio between the main and side channels, which is an indication of separation effectiveness, is defined as the objective. It is found that the degradation of the separation performance is caused by the unbalanced channel resistance ratio between the main and side channel routes from bifurcations to outlets. The effects of the three key parameters can be summarised as follows: (a) shortening the interval length between bifurcations moderately reduces the differences in the flow rate ratios; (b) extending the length of the main channel from the main outlet is effective for achieving a uniformity of flow rate ratio but ineffective in changing the velocity difference of the side channels and (c) decreasing the lengths of side channels from upstream to downstream is effective for both obtaining a uniform flow rate ratio and reducing the differences in the flow velocities between the side branch channels. An optimisation process combining the three parameters is suggested as this integration approach leads to fast convergent process and also offers flexible design options for satisfying different requirements.

  17. Using Lean principles to optimise inpatient phlebotomy services.

    Science.gov (United States)

    Le, Rachel D; Melanson, Stacy E F; Santos, Katherine S; Paredes, Jose D; Baum, Jonathan M; Goonan, Ellen M; Torrence-Hill, Joi N; Gustafson, Michael L; Tanasijevic, Milenko J

    2014-08-01

    In the USA, inpatient phlebotomy services are under constant operational pressure to optimise workflow, improve timeliness of blood draws, and decrease error in the context of increasing patient volume and complexity of work. To date, the principles of Lean continuous process improvement have been rarely applied to inpatient phlebotomy. To optimise supply replenishment and cart standardisation, communication and workload management, blood draw process standardisation, and rounding schedules and assignments using Lean principles in inpatient phlebotomy services. We conducted four Lean process improvement events and implemented a number of interventions in inpatient phlebotomy over a 9-month period. We then assessed their impact using three primary metrics: (1) percentage of phlebotomists drawing their first patient by 05:30 for 05:00 rounds, (2) percentage of phlebotomists completing 08:00 rounds by 09:30, and (3) number of errors per 1000 draws. We saw marked increases in the percentage of phlebotomists drawing their first patient by 05:30, and the percentage of phlebotomists completing rounds by 09:30 postprocess improvement. A decrease in the number of errors per 1000 draws was also observed. This study illustrates how continuous process improvement through Lean can optimise workflow, improve timeliness, and decrease error in inpatient phlebotomy. We believe this manuscript adds to the field of clinical pathology as it can be used as a guide for other laboratories with similar goals of optimising workflow, improving timeliness, and decreasing error, providing examples of interventions and metrics that can be tailored to specific laboratories with particular services and resources. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  18. Integrated planning tool for optimisation in municipal home care

    OpenAIRE

    Røhne, Mette; Sandåker, Torjus; Ausen, Dag; Grut, Lisbet

    2016-01-01

    Purpose: The objective is to improve collaboration and enhance quality of care services in municipal, home care services by implementing and developing an integrated planning tool making use of optimisation technology for better decision support. The project will through piloting and action based research establish knowledge on change in work processes to improve collaboration and efficiency. Context: A planning tool called Spider has been piloted in home care in Horten municipality since 201...

  19. Parameter Screening and Optimisation for ILP Using Designed Experiments

    Science.gov (United States)

    Srinivasan, Ashwin; Ramakrishnan, Ganesh

    Reports of experiments conducted with an Inductive Logic Programming system rarely describe how specific values of parameters of the system are arrived at when constructing models. Usually, no attempt is made to identify sensitive parameters, and those that are used are often given "factory-supplied" default values, or values obtained from some non-systematic exploratory analysis. The immediate consequence of this is, of course, that it is not clear if better models could have been obtained if some form of parameter selection and optimisation had been performed. Questions follow inevitably on the experiments themselves: specifically, are all algorithms being treated fairly, and is the exploratory phase sufficiently well-defined to allow the experiments to be replicated? In this paper, we investigate the use of parameter selection and optimisation techniques grouped under the study of experimental design. Screening and "response surface" methods determine, in turn, sensitive parameters and good values for these parameters. This combined use of parameter selection and response surface-driven optimisation has a long history of application in industrial engineering, and its role in ILP is investigated using two well-known benchmarks. The results suggest that computational overheads from this preliminary phase are not substantial, and that much can be gained, both on improving system performance and on enabling controlled experimentation, by adopting well-established procedures such as the ones proposed here.

  20. Statistical optimisation techniques in fatigue signal editing problem

    Energy Technology Data Exchange (ETDEWEB)

    Nopiah, Z. M.; Osman, M. H. [Fundamental Engineering Studies Unit Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM (Malaysia); Baharin, N.; Abdullah, S. [Department of Mechanical and Materials Engineering Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM (Malaysia)

    2015-02-03

    Success in fatigue signal editing is determined by the level of length reduction without compromising statistical constraints. A great reduction rate can be achieved by removing small amplitude cycles from the recorded signal. The long recorded signal sometimes renders the cycle-to-cycle editing process daunting. This has encouraged researchers to focus on the segment-based approach. This paper discusses joint application of the Running Damage Extraction (RDE) technique and single constrained Genetic Algorithm (GA) in fatigue signal editing optimisation.. In the first section, the RDE technique is used to restructure and summarise the fatigue strain. This technique combines the overlapping window and fatigue strain-life models. It is designed to identify and isolate the fatigue events that exist in the variable amplitude strain data into different segments whereby the retention of statistical parameters and the vibration energy are considered. In the second section, the fatigue data editing problem is formulated as a constrained single optimisation problem that can be solved using GA method. The GA produces the shortest edited fatigue signal by selecting appropriate segments from a pool of labelling segments. Challenges arise due to constraints on the segment selection by deviation level over three signal properties, namely cumulative fatigue damage, root mean square and kurtosis values. Experimental results over several case studies show that the idea of solving fatigue signal editing within a framework of optimisation is effective and automatic, and that the GA is robust for constrained segment selection.

  1. Optimising the Target and Capture Sections of the Neutrino Factory

    CERN Document Server

    Hansen, Ole Martin; Stapnes, Steinar

    The Neutrino Factory is designed to produce an intense high energy neutrino beam from stored muons. The majority of the muons are obtained from the decay of pions, produced by a proton beam impinging on a free-flowing mercury-jet target and captured by a high magnetic field. It is important to capture a large fraction of the produced pions to maximize the intensity of the neutrino beam. Various optimisation studies have been performed with the aim of maximising the muon influx to the accelerator and thus the neutrino beam intensity. The optimisation studies were performed with the use of Monte Carlo simulation tools. The production of secondary particles, by interactions between the incoming proton beam and the mercury target, was optimised by varying the proton beam impact position and impact angles on the target. The proton beam and target interaction region was studied and showed to be off the central axis of the capture section in the baseline configuration. The off-centred interaction region resulted in ...

  2. Direct and Indirect Gradient Control for Static Optimisation

    Institute of Scientific and Technical Information of China (English)

    Yi Cao

    2005-01-01

    Static "self-optimising" control is an important concept, which provides a link between static optimisation and control[1]. According to the concept, a dynamic control system could be configured in such a way that when a set of certain variables are maintained at their setpoints, the overall process operation is automatically optimal or near optimal at steadystate in the presence of disturbances. A novel approach using constrained gradient control to achieve "self-optimisation" has been proposed by Cao[2]. However, for most process plants, the information required to get the gradient measure may not be available in real-time. In such cases, controlled variable selection has to be carried out based on measurable candidates. In this work, the idea of direct gradient control has been extended to controlled variable selection based on gradient sensitivity analysis (indirect gradient control). New criteria, which indicate the sensitivity of the gradient function to disturbances and implementation errors, have been derived for selection. The particular case study shows that the controlled variables selected by gradient sensitivity measures are able to achieve near optimal performance.

  3. Optimisation of Lilla Edet Landslide GPS Monitoring Network

    Science.gov (United States)

    Alizadeh-Khameneh, M. A.; Eshagh, M.; Sjöberg, L. E.

    2015-06-01

    Since the year 2000, some periodic investigations have been performed in the Lilla Edet region to monitor and possibly determine the landslide of the area with GPS measurements. The responsible consultant has conducted this project by setting up some stable stations for GPS receivers in the risky areas of Lilla Edet and measured the independent baselines amongst the stations according to their observation plan. Here, we optimise the existing surveying network and determine the optimal configuration of the observation plan based on different criteria.We aim to optimise the current network to become sensitive to detect 5 mm possible displacements in each net point. The network quality criteria of precision, reliability and cost are used as object functions to perform single-, bi- and multi-objective optimisation models. It has been shown in the results that the single-objective model of reliability, which is constrained to the precision, provides much higher precision than the defined criterion by preserving almost all of the observations. However, in this study, the multi-objective model can fulfil all the mentioned quality criteria of the network by 17% less measurements than the original observation plan, meaning 17%of saving time, cost and effort in the project.

  4. Module detection in complex networks using integer optimisation

    Directory of Open Access Journals (Sweden)

    Tsoka Sophia

    2010-11-01

    Full Text Available Abstract Background The detection of modules or community structure is widely used to reveal the underlying properties of complex networks in biology, as well as physical and social sciences. Since the adoption of modularity as a measure of network topological properties, several methodologies for the discovery of community structure based on modularity maximisation have been developed. However, satisfactory partitions of large graphs with modest computational resources are particularly challenging due to the NP-hard nature of the related optimisation problem. Furthermore, it has been suggested that optimising the modularity metric can reach a resolution limit whereby the algorithm fails to detect smaller communities than a specific size in large networks. Results We present a novel solution approach to identify community structure in large complex networks and address resolution limitations in module detection. The proposed algorithm employs modularity to express network community structure and it is based on mixed integer optimisation models. The solution procedure is extended through an iterative procedure to diminish effects that tend to agglomerate smaller modules (resolution limitations. Conclusions A comprehensive comparative analysis of methodologies for module detection based on modularity maximisation shows that our approach outperforms previously reported methods. Furthermore, in contrast to previous reports, we propose a strategy to handle resolution limitations in modularity maximisation. Overall, we illustrate ways to improve existing methodologies for community structure identification so as to increase its efficiency and applicability.

  5. Customisable 3D printed microfluidics for integrated analysis and optimisation.

    Science.gov (United States)

    Monaghan, T; Harding, M J; Harris, R A; Friel, R J; Christie, S D R

    2016-08-16

    The formation of smart Lab-on-a-Chip (LOC) devices featuring integrated sensing optics is currently hindered by convoluted and expensive manufacturing procedures. In this work, a series of 3D-printed LOC devices were designed and manufactured via stereolithography (SL) in a matter of hours. The spectroscopic performance of a variety of optical fibre combinations were tested, and the optimum path length for performing Ultraviolet-visible (UV-vis) spectroscopy determined. The information gained in these trials was then used in a reaction optimisation for the formation of carvone semicarbazone. The production of high resolution surface channels (100-500 μm) means that these devices were capable of handling a wide range of concentrations (9 μM-38 mM), and are ideally suited to both analyte detection and process optimisation. This ability to tailor the chip design and its integrated features as a direct result of the reaction being assessed, at such a low time and cost penalty greatly increases the user's ability to optimise both their device and reaction. As a result of the information gained in this investigation, we are able to report the first instance of a 3D-printed LOC device with fully integrated, in-line monitoring capabilities via the use of embedded optical fibres capable of performing UV-vis spectroscopy directly inside micro channels.

  6. MOPTOP: a multi-colour optimised optical polarimeter

    Science.gov (United States)

    Jermak, Helen; Steele, Iain A.; Smith, Robert J.

    2016-08-01

    We present the design and science case for the Liverpool Telescope's fourth-generation polarimeter; MOPTOP: a Multicolour OPTimised Optical Polarimeter which is optimised for sensitivity and bi-colour observations. We introduce an optimised polarimeter which is as far as possible limited only by the photon counting efficiency of the detectors. Using a combination of CMOS cameras, a continuously rotating half-wave plate and a wire grid polarising beamsplitter, we predict we can accurately measure the polarisation of sources to 1% at 19th magnitude in 10 minutes on a 2 metre telescope. For brighter sources we anticipate much low systematics (design also gives the ability to measure polarization and photometric variability on timescales as short as a few seconds. Overall the instrument will allow accurate measurements of the intra-nightly variability of the polarisation of sources such as gamma-ray bursts and blazars (AGN orientated with the jet pointing toward the observer), allowing the constraint of magnetic field models revealing more information about the formation, ejection and collimation of jets.

  7. Crystal structure optimisation using an auxiliary equation of state.

    Science.gov (United States)

    Jackson, Adam J; Skelton, Jonathan M; Hendon, Christopher H; Butler, Keith T; Walsh, Aron

    2015-11-14

    Standard procedures for local crystal-structure optimisation involve numerous energy and force calculations. It is common to calculate an energy-volume curve, fitting an equation of state around the equilibrium cell volume. This is a computationally intensive process, in particular, for low-symmetry crystal structures where each isochoric optimisation involves energy minimisation over many degrees of freedom. Such procedures can be prohibitive for non-local exchange-correlation functionals or other "beyond" density functional theory electronic structure techniques, particularly where analytical gradients are not available. We present a simple approach for efficient optimisation of crystal structures based on a known equation of state. The equilibrium volume can be predicted from one single-point calculation and refined with successive calculations if required. The approach is validated for PbS, PbTe, ZnS, and ZnTe using nine density functionals and applied to the quaternary semiconductor Cu2ZnSnS4 and the magnetic metal-organic framework HKUST-1.

  8. Crystal structure optimisation using an auxiliary equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Adam J.; Skelton, Jonathan M.; Hendon, Christopher H.; Butler, Keith T. [Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Walsh, Aron, E-mail: a.walsh@bath.ac.uk [Centre for Sustainable Chemical Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Global E" 3 Institute and Department of Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2015-11-14

    Standard procedures for local crystal-structure optimisation involve numerous energy and force calculations. It is common to calculate an energy–volume curve, fitting an equation of state around the equilibrium cell volume. This is a computationally intensive process, in particular, for low-symmetry crystal structures where each isochoric optimisation involves energy minimisation over many degrees of freedom. Such procedures can be prohibitive for non-local exchange-correlation functionals or other “beyond” density functional theory electronic structure techniques, particularly where analytical gradients are not available. We present a simple approach for efficient optimisation of crystal structures based on a known equation of state. The equilibrium volume can be predicted from one single-point calculation and refined with successive calculations if required. The approach is validated for PbS, PbTe, ZnS, and ZnTe using nine density functionals and applied to the quaternary semiconductor Cu{sub 2}ZnSnS{sub 4} and the magnetic metal-organic framework HKUST-1.

  9. Numerical optimisation of an axial turbine; Numerische Optimierung einer Axialturbine

    Energy Technology Data Exchange (ETDEWEB)

    Welzel, B.

    1998-12-31

    The author presents a method for automatic shape optimisation of components with internal or external flow. The method combines a program for numerical calculation of frictional turbulent flow with an optimisation algorithm. Algorithms are a simplex search strategy and an evolution strategy. The shape of the component to be optimized is variable due to shape parameters modified by the algorithm. For each shape, a flow calculation is carried out on whose basis a functional value like performance, loss, lift or resistivity is calculated. For validation, the optimisation method is used in simple examples with known solutions. It is applied. It is applied to the components of a slow-running axial turbine. Components with accelerated and delayed rotationally symmetric flow and 2D blade profiles are optimized. [Deutsch] Es wird eine Methode zur automatischen Formoptimierung durchstroemter oder umstroemter Bauteile vorgestellt. Diese koppelt ein Programm zur numerischen Berechnung reibungsbehafteter turbulenter Stroemungen mit einem Optimierungsalgorithmus. Dabei kommen als Algorithmen eine Simplex-Suchstrategie und eine Evolutionsstrategie zum Einsatz. Die Form des zu optimierenden Koerpers ist durch Formparameter, die vom Algorithmus veraendert werden, variabel. Fuer jede Form wird eine Stroemungsberechnung durchgefuehrt und mit dieser ein Funktionswert wie Wirkungsgrad, Verlust, Auftrieb oder Widerstandskraft berechnet. Die Optimierungsmethode wird zur Validierung in einfachen Beispielen mit bekannter Loesung eingesetzt. Zur Anwendung kommt sie in den einzelnen Komponenten einer langsamlaeufigen Axialturbine. Es werden Bauteile mit beschleunigter und verzoegerter rotationssymmetrischer Stroemung und 2D-Schaufelprofile optimiert. (orig.)

  10. Honeybee economics: optimisation of foraging in a variable world.

    Science.gov (United States)

    Stabentheiner, Anton; Kovac, Helmut

    2016-06-20

    In honeybees fast and efficient exploitation of nectar and pollen sources is achieved by persistent endothermy throughout the foraging cycle, which means extremely high energy costs. The need for food promotes maximisation of the intake rate, and the high costs call for energetic optimisation. Experiments on how honeybees resolve this conflict have to consider that foraging takes place in a variable environment concerning microclimate and food quality and availability. Here we report, in simultaneous measurements of energy costs, gains, and intake rate and efficiency, how honeybee foragers manage this challenge in their highly variable environment. If possible, during unlimited sucrose flow, they follow an 'investment-guided' ('time is honey') economic strategy promising increased returns. They maximise net intake rate by investing both own heat production and solar heat to increase body temperature to a level which guarantees a high suction velocity. They switch to an 'economizing' ('save the honey') optimisation of energetic efficiency if the intake rate is restricted by the food source when an increased body temperature would not guarantee a high intake rate. With this flexible and graded change between economic strategies honeybees can do both maximise colony intake rate and optimise foraging efficiency in reaction to environmental variation.

  11. Milk bottom-up proteomics: method optimisation.

    Directory of Open Access Journals (Sweden)

    Delphine eVincent

    2016-01-01

    Full Text Available Milk is a complex fluid whose proteome displays a diverse set of proteins of high abundance such as caseins and medium to low abundance whey proteins such as ß-lactoglobulin, lactoferrin, immunoglobulins, glycoproteins, peptide hormones and enzymes. A sample preparation method that enables high reproducibility and throughput is key in reliably identifying proteins present or proteins responding to conditions such as a diet, health or genetics. Using skim milk samples from Jersey and Holstein-Friesian cows, we compared three extraction procedures which have not previously been applied to samples of cows’ milk. Method A (urea involved a simple dilution of the milk in a urea-based buffer, method B (TCA/acetone involved a trichloroacetic acid (TCA/acetone precipitation and method C (methanol/chloroform involved a tri-phasic partition method in chloroform/methanol solution. Protein assays, SDS-PAGE profiling, and trypsin digestion followed by nanoHPLC-electrospray ionisation-tandem mass spectrometry (nLC-ESI-MS/MS analyses were performed to assess their efficiency. Replicates were used at each analytical step (extraction, digestion, injection to assess reproducibility. Mass spectrometry (MS data are available via ProteomeXchange with identifier PXD002529. Overall 186 unique accessions, major and minor proteins, were identified with a combination of methods. Method C (methanol/chloroform yielded the best resolved SDS-patterns and highest protein recovery rates, method A (urea yielded the greatest number of accessions, and, of the three procedures, method B (TCA/acetone was the least compatible of all with a wide range of downstream analytical procedures. Our results also highlighted breed differences between the proteins in milk of Jersey and Holstein-Friesian cows.

  12. Techno-economic optimisation of energy systems; Contribution a l'optimisation technico-economique de systemes energetiques

    Energy Technology Data Exchange (ETDEWEB)

    Mansilla Pellen, Ch

    2006-07-15

    The traditional approach currently used to assess the economic interest of energy systems is based on a defined flow-sheet. Some studies have shown that the flow-sheets corresponding to the best thermodynamic efficiencies do not necessarily lead to the best production costs. A method called techno-economic optimisation was proposed. This method aims at minimising the production cost of a given energy system, including both investment and operating costs. It was implemented using genetic algorithms. This approach was compared to the heat integration method on two different examples, thus validating its interest. Techno-economic optimisation was then applied to different energy systems dealing with hydrogen as well as electricity production. (author)

  13. Optimisation of the Nonlinear Suspension Characteristics of a Light Commercial Vehicle

    Directory of Open Access Journals (Sweden)

    Dinçer Özcan

    2013-01-01

    Full Text Available The optimum functional characteristics of suspension components, namely, linear/nonlinear spring and nonlinear damper characteristic functions are determined using simple lumped parameter models. A quarter car model is used to represent the front independent suspension, and a half car model is used to represent the rear solid axle suspension of a light commercial vehicle. The functional shapes of the suspension characteristics used in the optimisation process are based on typical shapes supplied by a car manufacturer. The complexity of a nonlinear function optimisation problem is reduced by scaling it up or down from the aforementioned shape in the optimisation process. The nonlinear optimised suspension characteristics are first obtained using lower complexity lumped parameter models. Then, the performance of the optimised suspension units are verified using the higher fidelity and more realistic Carmaker model. An interactive software module is developed to ease the nonlinear suspension optimisation process using the Matlab Graphical User Interface tool.

  14. Software tools overview : process integration, modelling and optimisation for energy saving and pollution reduction

    OpenAIRE

    Lam, Hon Loong; Klemeš, Jiri; Kravanja, Zdravko; Varbanov, Petar

    2012-01-01

    This paper provides an overview of software tools based on long experience andapplications in the area of process integration, modelling and optimisation. The first part reviews the current design practice and the development of supporting software tools. Those are categorised as: (1) process integration and retrofit analysis tools, (2) general mathematical modelling suites with optimisation libraries, (3) flowsheeting simulation and (4) graph-based process optimisation tools. The second part...

  15. Optimisation of logistics processes of energy grass collection

    Science.gov (United States)

    Bányai, Tamás.

    2010-05-01

    The collection of energy grass is a logistics-intensive process [1]. The optimal design and control of transportation and collection subprocesses is a critical point of the supply chain. To avoid irresponsible decisions by right of experience and intuition, the optimisation and analysis of collection processes based on mathematical models and methods is the scientific suggestible way. Within the frame of this work, the author focuses on the optimisation possibilities of the collection processes, especially from the point of view transportation and related warehousing operations. However the developed optimisation methods in the literature [2] take into account the harvesting processes, county-specific yields, transportation distances, erosion constraints, machinery specifications, and other key variables, but the possibility of more collection points and the multi-level collection were not taken into consideration. The possible areas of using energy grass is very wide (energetically use, biogas and bio alcohol production, paper and textile industry, industrial fibre material, foddering purposes, biological soil protection [3], etc.), so not only a single level but also a multi-level collection system with more collection and production facilities has to be taken into consideration. The input parameters of the optimisation problem are the followings: total amount of energy grass to be harvested in each region; specific facility costs of collection, warehousing and production units; specific costs of transportation resources; pre-scheduling of harvesting process; specific transportation and warehousing costs; pre-scheduling of processing of energy grass at each facility (exclusive warehousing). The model take into consideration the following assumptions: (1) cooperative relation among processing and production facilties, (2) capacity constraints are not ignored, (3) the cost function of transportation is non-linear, (4) the drivers conditions are ignored. The

  16. Optimisation of fertiliser rates in crop production against energy use indicators

    DEFF Research Database (Denmark)

    Rossner, Helis; Ritz, Christian; Astover, Alar

    2014-01-01

    Optimising mineral nitrogen (N) use in crop production is inevitable target as mineral fertilisers reflectone of the highest inputs both in terms of economy and energy. The aim of the study was to comparethe relationship between the rate of N fertiliser application and different measures of energy.......05) optimisation. Both the new combined indices gave optimum N norms in between the rate ofER an EG. Composted cow manure background did not affect mineral N optimisation significantly. Wesuggest optimisation of mineral N according to bi-dimensional parameters as they capture important fea-tures of production...

  17. An Inverse Robust Optimisation Approach for a Class of Vehicle Routing Problems under Uncertainty

    Directory of Open Access Journals (Sweden)

    Liang Sun

    2016-01-01

    Full Text Available There is a trade-off between the total penalty paid to customers (TPC and the total transportation cost (TTC in depot for vehicle routing problems under uncertainty (VRPU. The trade-off refers to the fact that the TTC in depot inevitably increases when the TPC decreases and vice versa. With respect to this issue, the vehicle routing problem (VRP with uncertain customer demand and travel time was studied to optimise the TPC and the TTC in depot. In addition, an inverse robust optimisation approach was proposed to solve this kind of VRPU by combining the ideas of inverse optimisation and robust optimisation so as to improve both the TPC and the TTC in depot. The method aimed to improve the corresponding TTC of the robust optimisation solution under the minimum TPC through minimising the adjustment of benchmark road transportation cost. According to the characteristics of the inverse robust optimisation model, a genetic algorithm (GA and column generation algorithm are combined to solve the problem. Moreover, 39 test problems are solved by using an inverse robust optimisation approach: the results show that both the TPC and TTC obtained by using the inverse robust optimisation approach are less than those calculated using a robust optimisation approach.

  18. Optimisation of groundwater level monitoring networks using geostatistical modelling based on the Spartan family variogram and a genetic algorithm method

    Science.gov (United States)

    Parasyris, Antonios E.; Spanoudaki, Katerina; Kampanis, Nikolaos A.

    2016-04-01

    optimization problem (the best wells to retain in the monitoring network) depends on the total number of wells removed; this number is a management decision. The water level monitoring network of Mires basin has been optimized 6 times by removing 5, 8, 12, 15, 20 and 25 wells from the original network. In order to achieve the optimum solution in the minimum possible computational time, a stall generations criterion was set for each optimisation scenario. An improvement made to the classic genetic algorithm was the change of the mutation and crossover fraction in respect to the change of the mean fitness value. This results to a randomness in reproduction, if the solution converges, to avoid local minima, or, in a more educated reproduction (higher crossover ratio) when there is higher change in the mean fitness value. The choice of integer genetic algorithm in MATLAB 2015a poses the restriction of adding custom selection and crossover-mutation functions. Therefore, custom population and crossover-mutation-selection functions have been created to set the initial population type to custom and have the ability to change the mutation crossover probability in respect to the convergence of the genetic algorithm, achieving thus higher accuracy. The application of the network optimisation tool to Mires basin indicates that 25 wells can be removed with a relatively small deterioration of the groundwater level map. The results indicate the robustness of the network optimisation tool: Wells were removed from high well-density areas while preserving the spatial pattern of the original groundwater level map. Varouchakis, E. A. and D. T. Hristopulos (2013). "Improvement of groundwater level prediction in sparsely gauged basins using physical laws and local geographic features as auxiliary variables." Advances in Water Resources 52: 34-49.

  19. Co-optimisation of phosphorus and nitrogen removal in stormwater biofilters: the role of filter media, vegetation and saturated zone.

    Science.gov (United States)

    Glaister, Bonnie J; Fletcher, Tim D; Cook, Perran L M; Hatt, Belinda E

    2014-01-01

    Biofilters have been shown to effectively treat stormwater and achieve nutrient load reduction targets. However, effluent concentrations of nitrogen and phosphorus typically exceed environmental targets for receiving water protection. This study investigates the role of filter media, vegetation and a saturated zone (SZ) in achieving co-optimised nitrogen and phosphorus removal in biofilters. Twenty biofilter columns were monitored over a 12-month period of dosing with semi-synthetic stormwater. The frequency of dosing was altered seasonally to examine the impact of hydrologic variability. Very good nutrient removal (90% total phosphorus, 89% total nitrogen) could be achieved by incorporating vegetation, an SZ and Skye sand, a naturally occurring iron-rich filter medium. This design maintained nutrient removal at or below water quality guideline concentrations throughout the experiment, demonstrating resilience to wetting-drying fluctuations. The results also highlighted the benefit of including an SZ to maintain treatment performance over extended dry periods. These findings represent progress towards designing biofilters which co-optimise nitrogen and phosphorus removal and comply with water quality guidelines.

  20. New generation of pattern materials for investment casting

    Directory of Open Access Journals (Sweden)

    A. Karwiński

    2011-01-01

    Full Text Available Pattern mixtures (so-called soft mixtures currently used in investment casting are composed of paraffin, stearin, and - to a lesser extent –of ceresin, polyethylene wax and other natural and synthetic waxes. During studies, several types of soft pattern mixtures were developedby modifying the already existing compositions with appropriate additives. Based on the studies of physico-chemical and performanceproperties, the composition of pattern material was optimised.

  1. Challenges of additive manufacturing technologies from an optimisation perspective

    Directory of Open Access Journals (Sweden)

    Guessasma Sofiane

    2015-01-01

    Full Text Available Three-dimensional printing offers varied possibilities of design that can be bridged to optimisation tools. In this review paper, a critical opinion on optimal design is delivered to show limits, benefits and ways of improvement in additive manufacturing. This review emphasises on design constrains related to additive manufacturing and differences that may appear between virtual and real design. These differences are explored based on 3D imaging techniques that are intended to show defect related processing. Guidelines of safe use of the term “optimal design” are derived based on 3D structural information.

  2. Semiconductor lasers as integrated optical biosensors: sensitivity optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Coote, J; Sweeney, S J [Advanced Technology Institute, University of Surrey, Guildford, UK GU2 7XH (United Kingdom)

    2007-07-15

    Semiconductor lasers contain both a light source and waveguide, rendering them suitable for adaptation to evanescent field biosensing. One-dimensional simulations using the beam propagation method have been carried out for planar semiconductor waveguide structures, with a view to maximising sensitivity of the effective index to changes in the refractive index and thickness of a film on the waveguide surface. Various structural parameters are investigated and it is found that thinning the upper cladding layer maximises the sensitivity. Implications for laser operation are considered, and an optimised structure is proposed. Surface layer index and thickness resolutions of 0.2 and 2nm are predicted.

  3. Review of magnesium hydride-based materials: development and optimisation

    Science.gov (United States)

    Crivello, J.-C.; Dam, B.; Denys, R. V.; Dornheim, M.; Grant, D. M.; Huot, J.; Jensen, T. R.; de Jongh, P.; Latroche, M.; Milanese, C.; Milčius, D.; Walker, G. S.; Webb, C. J.; Zlotea, C.; Yartys, V. A.

    2016-02-01

    Magnesium hydride has been studied extensively for applications as a hydrogen storage material owing to the favourable cost and high gravimetric and volumetric hydrogen densities. However, its high enthalpy of decomposition necessitates high working temperatures for hydrogen desorption while the slow rates for some processes such as hydrogen diffusion through the bulk create challenges for large-scale implementation. The present paper reviews fundamentals of the Mg-H system and looks at the recent advances in the optimisation of magnesium hydride as a hydrogen storage material through the use of catalytic additives, incorporation of defects and an understanding of the rate-limiting processes during absorption and desorption.

  4. Adaptive optimisation of a generalised phase contrast beam shaping system

    Science.gov (United States)

    Kenny, F.; Choi, F. S.; Glückstad, J.; Booth, M. J.

    2015-05-01

    The generalised phase contrast (GPC) method provides versatile and efficient light shaping for a range of applications. We have implemented a generalised phase contrast system that used two passes on a single spatial light modulator (SLM). Both the pupil phase distribution and the phase contrast filter were generated by the SLM. This provided extra flexibility and control over the parameters of the system including the phase step magnitude, shape, radius and position of the filter. A feedback method for the on-line optimisation of these properties was also developed. Using feedback from images of the generated light field, it was possible to dynamically adjust the phase filter parameters to provide optimum contrast.

  5. Optimisation of biodiesel production by sunflower oil transesterification.

    Science.gov (United States)

    Antolín, G; Tinaut, F V; Briceño, Y; Castaño, V; Pérez, C; Ramírez, A I

    2002-06-01

    In this work the transformation process of sunflower oil in order to obtain biodiesel by means of transesterification was studied. Taguchi's methodology was chosen for the optimisation of the most important variables (temperature conditions, reactants proportion and methods of purification), with the purpose of obtaining a high quality biodiesel that fulfils the European pre-legislation with the maximum process yield. Finally, sunflower methyl esters were characterised to test their properties as fuels in diesel engines, such as viscosity, flash point, cold filter plugging point and acid value. Results showed that biodiesel obtained under the optimum conditions is an excellent substitute for fossil fuels.

  6. An optimisation framework for determination of capacity in railway networks

    DEFF Research Database (Denmark)

    Jensen, Lars Wittrup

    2015-01-01

    Within the railway industry, high quality estimates on railway capacity is crucial information, that helps railway companies to utilise the expensive (infrastructure) resources as efficiently as possible. This paper therefore proposes an optimisation framework to estimate the capacity of a railway...... to the train types. This is done using a mathematical model which is solved with a heuristic. The developed approach is used on a case network to obtain the capacity of the given railway system. Furthermore, we test different parameters to explore computation time, precision and sensitivity to input...

  7. Word Sense Disambiguation using Optimised Combinations of Knowledge Sources

    CERN Document Server

    Wilks, Y A; Wilks, Yorick; Stevenson, Mark

    1998-01-01

    Word sense disambiguation algorithms, with few exceptions, have made use of only one lexical knowledge source. We describe a system which performs unrestricted word sense disambiguation (on all content words in free text) by combining different knowledge sources: semantic preferences, dictionary definitions and subject/domain codes along with part-of-speech tags. The usefulness of these sources is optimised by means of a learning algorithm. We also describe the creation of a new sense tagged corpus by combining existing resources. Tested accuracy of our approach on this corpus exceeds 92%, demonstrating the viability of all-word disambiguation rather than restricting oneself to a small sample.

  8. Optimising performance in steady state for a supermarket refrigeration system

    DEFF Research Database (Denmark)

    Green, Torben; Kinnaert, Michel; Razavi-Far, Roozbeh

    2012-01-01

    Using a supermarket refrigeration system as an illustrative example, the paper postulates that by appropriately utilising knowledge of plant operation, the plant wide performance can be optimised based on a small set of variables. Focusing on steady state operations, the total system performance...... is shown to predominantly be influenced by the suction pressure. Employing appropriate performance function leads to conclusions on the choice of set-point for the suction pressure that are contrary to the existing practice. Analysis of the resulting data leads to a simple method for finding optimal...

  9. Optimisation is at the heart of the operation.

    Science.gov (United States)

    Jones, Darren

    2013-11-01

    In our other article based around operating theatres in this issue of HEJ (see pages 64-72), we examine how some of the latest technology is benefiting users, but in this article--with all areas of the NHS charged with reducing energy consumption and cutting carbon emissions--Darren Jones, MD at carbon and energy management specialist, Low Carbon Europe, takes a detailed look, with the help of a 'real-life' case study based on recent experience at London's Heart Hospital, at operating theatre optimisation and HTM 03-01 audits.

  10. Optimised quantum hacking of superconducting nanowire single-photon detectors

    CERN Document Server

    Tanner, Michael G; Hadfield, Robert H

    2013-01-01

    We explore optimised control of superconducting nanowire single-photon detectors (SNSPDs) through bright illumination. We consider the behaviour of the SNSPD in the shunted configuration (a practical measure to avoid latching) in long-running quantum key distribution experiments. We propose and demonstrate an effective bright-light attack on this realistic configuration, by applying transient blinding illumination lasting for a fraction of a microsecond and producing several deterministic fake clicks during this time. We show that this attack does not lead to elevated timing jitter in the spoofed output pulse, and is hence not introducing significant errors. Five different SNSPD chip designs were tested. We consider possible countermeasures to this attack.

  11. Operation, optimisation, and performance of the DELPHI RICH detectors

    CERN Document Server

    Albrecht, E; Augustinus, A; Baillon, Paul; Battaglia, Marco; Bloch, D; Boudinov, E; Brunet, J M; Carrié, P; Cavalli, P; Christophel, E; Davenport, M; Dracos, M; Eklund, L; Erzen, B; Fischer, P A; Fokitis, E; Fontanelli, F; Gracco, Valerio; Hallgren, A; Joram, C; Juillot, P; Kjaer, N J; Kluit, P M; Lenzen, G; Liko, D; Mahon, J R; Maltezos, S; Markou, A; Neufeld, N; Nielsen, B S; Petrolini, A; Podobnik, T; Polok, G; Sajot, G; Sannino, M; Schyns, E; Strub, R; Tegenfeldt, F; Thadome, J; Tristram, G; Ullaland, O; Vulpen, I V

    1999-01-01

    The Ring Imaging Cherenkov detectors of DELPHI represent a large-scale particle identification system which covers almost the full angular acceptance of DELPHI. The combination of liquid and gas radiators (C sub 4 F sub 1 sub 0 , C sub 5 F sub 1 sub 2 , and C sub 6 F sub 1 sub 4) provides particle identification over the whole secondary particle momentum spectrum at LEP I and LEP II. Continuing optimisation on the hardware as well as on the online and offline software level have resulted in a stable operation of the complete detector system for more than five years at full physics performance.

  12. Transmitter antenna placement in indoor environments using particle swarm optimisation

    Science.gov (United States)

    Talepour, Zeinab; Tavakoli, Saeed; Ahmadi-Shokouh, Javad

    2013-07-01

    The aim of this article is to suitably locate the minimum number of transmitter antennas in a given indoor environment to achieve good propagation coverage. To calculate the electromagnetic field in various points of the environment, we develop a software engine, named ray-tracing engine (RTE), in Matlab. To achieve realistic calculations, all parameters of geometry and material of building are considered. Particle swarm optimisation is employed to determine good location of transmitters. Simulation results show that a full coverage is obtained through suitably locating three transmitters.

  13. Optimising the Target and Capture Sections of the Neutrino Factory

    OpenAIRE

    Hansen, Ole Martin

    2016-01-01

    The Neutrino Factory is designed to produce an intense high energy neutrino beam from stored muons. The majority of the muons are obtained from the decay of pions, produced by a proton beam impinging on a free-flowing mercury-jet target and captured by a high magnetic field. It is important to capture a large fraction of the produced pions to maximize the intensity of the neutrino beam. Various optimisation studies have been performed with the aim of maximising the muon influx to the accel...

  14. Study of heuristics in ant system for nuclear reload optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Alan M.M. de; Schirru, Roberto; Silva, Fernando C. da; Machado, Marcelo D.; Medeiros, Jose A.C.C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mail: alan@lmp.ufrj.br; schirru@lmp.ufrj.br; fernando@con.ufrj.br; marcelo@lmp.ufrj.br; canedo@lmp.ufrj.br

    2007-07-01

    A Pressurized Water Reactor core must be reloaded every time the fuel burnup reaches a level when it is not possible to sustain nominal power operation. The nuclear core fuel reload optimization consists in finding a burned-up and fresh-fuel-assembly loading pattern that maximizes the number of effective full power days, minimizing the relationship cost/benefit. This problem is NP-hard, meaning that complexity grows exponentially with the number of fuel assemblies in the core. Besides that, the problem is non-linear and its search space is highly discontinual and multimodal. In this work a parallel computational system based on Ant Colony System (ACS) called Artificial-Ant-Colony Networks is used to solve the nuclear reactor core fuel reload optimization problem, with compatibles heuristics. ACS is a system based on artificial agents that uses the reinforcement learning technique and was originally developed to solve the Traveling Salesman Problem, which is conceptually similar to the nuclear fuel reload problem. (author)

  15. Load testing circuit

    DEFF Research Database (Denmark)

    2009-01-01

    A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...

  16. Finite Element Optimised Back Analysis of In Situ Stress Field and Stability Analysis of Shaft Wall in the Underground Gas Storage

    Directory of Open Access Journals (Sweden)

    Yifei Yan

    2016-01-01

    Full Text Available A novel optimised back analysis method is proposed in this paper. The in situ stress field of an underground gas storage (UGS reservoir in a Turkey salt cavern is analysed by the basic theory of elastic mechanics. A finite element method is implemented to optimise and approximate the objective function by systematically adjusting boundary loads. Optimising calculation is performed based on a novel method to reduce the error between measurement and calculation as much as possible. Compared with common back analysis methods such as regression method, the method proposed can further improve the calculation precision. By constructing a large circular geometric model, the effect of stress concentration is eliminated and a minimum difference between computed and measured stress can be guaranteed in the rectangular objective region. The efficiency of the proposed method is investigated and confirmed by its capability on restoring in situ stress field, which agrees well with experimental results. The characteristics of stress distribution of chosen UGS wells are obtained based on the back analysis results and by applying the corresponding fracture criterion, the shaft walls are proven safe.

  17. Design and manufacture of Portland cement - application of sensitivity analysis in exploration and optimisation Part II. Optimisation

    DEFF Research Database (Denmark)

    Svinning, K.; Høskuldsson, Agnar

    2006-01-01

    A program for a model-based optimisation has been developed. The program contains two subprograms. The first one does minimising or maximising constrained by one original PLS-component or one equal to a combination of several. The second one does searching for the optimal combination of PLS......-components, which gives max or min y. The program has proved to be applicable for achieving realistic results for implementation in the design of Portland cement with respect to performance and in the quality control during production....

  18. Scaling and kinematics optimisation of the scapula and thorax in upper limb musculoskeletal models.

    Science.gov (United States)

    Prinold, Joe A I; Bull, Anthony M J

    2014-08-22

    Accurate representation of individual scapula kinematics and subject geometries is vital in musculoskeletal models applied to upper limb pathology and performance. In applying individual kinematics to a model's cadaveric geometry, model constraints are commonly prescriptive. These rely on thorax scaling to effectively define the scapula's path but do not consider the area underneath the scapula in scaling, and assume a fixed conoid ligament length. These constraints may not allow continuous solutions or close agreement with directly measured kinematics. A novel method is presented to scale the thorax based on palpated scapula landmarks. The scapula and clavicle kinematics are optimised with the constraint that the scapula medial border does not penetrate the thorax. Conoid ligament length is not used as a constraint. This method is simulated in the UK National Shoulder Model and compared to four other methods, including the standard technique, during three pull-up techniques (n=11). These are high-performance activities covering a large range of motion. Model solutions without substantial jumps in the joint kinematics data were improved from 23% of trials with the standard method, to 100% of trials with the new method. Agreement with measured kinematics was significantly improved (more than 10° closer at pthorax scaling correction factor were shown to be key. Separation of the medial border of the scapula from the thorax was large, although this may be physiologically correct due to the high loads and high arm elevation angles. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Optimisation of Immobilisation Conditions of β-galactosidase onto Chitosan Beads Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    He Chen

    2014-06-01

    Full Text Available Response Surface Methodology (RSM was advantageously used to optimize production conditions of immobilization of &beta-galactosidase onto chitosan beads. The influence of immobilization conditions on the immobilized enzyme activity was studied by using Box–Behnken experimental design, resulting in the appropriate average values of OD420 and the maximum value of immobilized enzyme activity. This illustrated that the experimental model was reliable and the experimental results were of good stability. Analysis of variance was performed to determine the adequacy and significance of the quadratic model. Various model parameters also could be seen from F value that the interaction between three factors was not particularly obvious, but effects of X1, X12, X22 X32 on the activity of immobilized enzyme were very obvious. The optimisation parameters studied in accordance with the results were: the appropriate average values of OD420 loaded in the range from 0.713 to 0.721. Furthermore the immobilized enzyme activity reached about 162U/g when the adsorption time, adsorption pH and cross-linking pH were 4h, 7 and 7, respectively. Thus, the relative activity of &beta-galactosidase immobilized increased more than 37% compared with the previous single factor research.

  20. Optimisation of surface passivation for highly reliable angular AMR sensors

    Energy Technology Data Exchange (ETDEWEB)

    Isler, M.; Christoffer, B.; Schoer, G.; Philippsen, B.; Mahnke, M.; Thorns, A.; Riethmueller, W.; Matz, H.; Tobescu, C. [NXP Semiconductors, Stresemannallee 101, 22529 Hamburg (Germany); Vanhelmont, F.; Wolters, R. [NXP Semiconductors, High Tech Campus 4, 5656 AE Eindhoven (Netherlands); Engelen, R.; Opran, A. [Philips Applied Technologies, High Tech Campus 7, 5656 AE Eindhoven (Netherlands); Stolk, P. [NXP Semiconductors, Gerstweg 2, 6534 AE Nijmegen (Netherlands)

    2010-02-15

    For state-of-the-art angular sensors based on the anisotropic magnetoresistive (AMR) effect in NiFe layers, the angular accuracy over time is limited by a drift of the offset voltage of the Wheatstone bridge configuration. It is shown that the interaction of the passivation layer and the magnetic permalloy is crucial for the drift of the offset voltage. By investigating the time and temperature dependence, the offset drift is attributed to stress relief of the PECVD passivation layer due to microstructural changes. Hydrogen outdiffusion from the passivation layer is involved in the observed stress evolution. It is demonstrated that optimising the passivation layer composition as well as the time of the subsequent annealing is beneficial for stress stabilisation of the permalloy-passivation layer system. With this optimised passivation layer a significant offset drift reduction of the NiFe Wheatstone bridge has been achieved resulting in highly accurate and long-term stable angular AMR sensors. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. An optimisation approach for shallow lake restoration through macrophyte management

    Science.gov (United States)

    Xu, Z. H.; Yin, X. A.; Yang, Z. F.

    2014-06-01

    Lake eutrophication is a serious global environmental issue. Phytoremediation is a promising, cost-effective, and environmentally friendly technology for water quality restoration. However, besides nutrient removal, macrophytes also deeply affect the hydrologic cycle of a lake system through evapotranspiration. Changes in hydrologic cycle caused by macrophytes have a great influence on lake water quality restoration. As a result of the two opposite effects of macrophytes on water quality restoration (i.e. an increase in macrophytes can increase nutrient removal and improve water quality while also increasing evapotranspiration, reducing water volume and consequently decreasing water quality), rational macrophyte control through planting and harvest is very important. In this study, a new approach is proposed to optimise the initial planting area and monthly harvest scheme of macrophytes for water quality restoration. The month-by-month effects of macrophyte management on lake water quality are considered. Baiyangdian Lake serves as a case study, using the common reed. It was found that water quality was closest to Grade III on the Chinese water quality scale when the reed planting area was 123 km2 (40% of the lake surface area) and most reeds would be harvested at the end of June. The optimisation approach proposed in this study will be a useful reference for lake restoration.

  2. An optimisation approach for shallow lake restoration through macrophyte management

    Directory of Open Access Journals (Sweden)

    Z. H. Xu

    2014-01-01

    Full Text Available Lake eutrophication is a serious global environmental issue. Phytoremediation is a promising, cost-effective, and environmentally friendly technology for water quality restoration. However, besides nutrient removal, macrophytes also deeply affect the hydrologic cycle of lake system through evapotranspiration. Changes in hydrologic cycle caused by macrophytes have a great influence on lake water quality restoration. As a result of the two opposite effects of macrophytes on water quality restoration (i.e. an increase in macrophytes can increase nutrient removal and improve water quality while also increasing evapotranspiration, reducing water volume and consequently decreasing water quality, rational macrophyte control through planting and harvest is very important. In this study, a new approach is proposed to optimise the initial planting area and monthly harvest scheme of macrophytes for water quality restoration. The month-by-month effects of macrophyte management on lake water quality are considered. Baiyangdian Lake serves as a case study, using the common reed. It was found that water quality was closest to Grade III on the Chinese water quality scale when the reed planting area was 123 km2 (40% of the lake surface area and most reeds would be harvested at the end of June. The optimisation approach proposed in this study will be a useful reference for lake restoration.

  3. Optimisation of Storage for Concentrated Solar Power Plants

    Directory of Open Access Journals (Sweden)

    Luigi Cirocco

    2014-12-01

    Full Text Available The proliferation of non-scheduled generation from renewable electrical energy sources such concentrated solar power (CSP presents a need for enabling scheduled generation by incorporating energy storage; either via directly coupled Thermal Energy Storage (TES or Electrical Storage Systems (ESS distributed within the electrical network or grid. The challenges for 100% renewable energy generation are: to minimise capitalisation cost and to maximise energy dispatch capacity. The aims of this review article are twofold: to review storage technologies and to survey the most appropriate optimisation techniques to determine optimal operation and size of storage of a system to operate in the Australian National Energy Market (NEM. Storage technologies are reviewed to establish indicative characterisations of energy density, conversion efficiency, charge/discharge rates and costings. A partitioning of optimisation techniques based on methods most appropriate for various time scales is performed: from “whole of year”, seasonal, monthly, weekly and daily averaging to those best suited matching the NEM bid timing of five minute dispatch bidding, averaged on the half hour as the trading settlement spot price. Finally, a selection of the most promising research directions and methods to determine the optimal operation and sizing of storage for renewables in the grid is presented.

  4. Nuclear power plant maintenance optimisation SENUF network activity

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstrand, R.; Bieth, M.; Pla, P.; Rieg, C.; Trampus, P. [Inst. for Energy, EC DG Joint Research Centre, Petten (Netherlands)

    2004-07-01

    During providing scientific and technical support to TACIS and PHARE nuclear safety programs a large amount of knowledge related to Russian design reactor systems has accumulated and led to creation of a new Network concerning Nuclear Safety in Central and Eastern Europe called ''Safety of Eastern European type Nuclear Facilities'' (SENUF). SENUF contributes to bring together all stakeholders of TACIS and PHARE: beneficiaries, end users, Eastern und Western nuclear industries, and thus, to favour fruitful technical exchanges and feedback of experience. At present the main focus of SENUF is the nuclear power plant maintenance as substantial element of plant operational safety as well as life management. A Working Group has been established on plant maintenance. One of its major tasks in 2004 is to prepare a status report on advanced strategies to optimise maintenance. Optimisation projects have an interface with the plant's overall life management program. Today, almost all plants involved in SENUF network have an explicit policy to extend their service life, thus, component ageing management, modernization and refurbishment actions became much more important. A database is also under development, which intends to help sharing the available knowledge and specific equipment and tools. (orig.)

  5. Computed tomography dose optimisation in cystic fibrosis:A review

    Institute of Scientific and Technical Information of China (English)

    Helena Ferris; Maria Twomey; Fiachra Moloney; Siobhan B O’Neill; Kevin Murphy; Owen J O’Connor; Michael Maher

    2016-01-01

    Cystic fibrosis(CF)is the most common autosomal recessive disease of the Caucasian population worldwide,with respiratory disease remaining the most relevant source of morbidity and mortality.Computed tomography(CT)is frequently used for monitoring disease complications and progression.Over the last fifteen years there has been a six-fold increase in the use of CT,which has lead to a growing concern in relation to cumulative radiation exposure.The challenge to the medical profession is to identify dose reduction strategies that meet acceptable image quality,but fulfil the requirements of a diagnostic quality CT.Dose-optimisation,particularly in CT,is essential as it reduces the chances of patients receiving cumulative radiation doses in excess of 100 m Sv,a dose deemed significant by the United Nations Scientific Committee on the Effects of Atomic Radiation.This review article explores the current trends in imaging in CF with particular emphasis on new developments in dose optimisation.

  6. Power and delay optimisation in multi-hop wireless networks

    KAUST Repository

    Xia, Li

    2014-02-05

    In this paper, we study the optimisation problem of transmission power and delay in a multi-hop wireless network consisting of multiple nodes. The goal is to determine the optimal policy of transmission rates at various buffer and channel states in order to minimise the power consumption and the queueing delay of the whole network. With the assumptions of interference-free links and independently and identically distributed (i.i.d.) channel states, we formulate this problem using a semi-open Jackson network model for data transmission and a Markov model for channel states transition. We derive a difference equation of the system performance under any two different policies. The necessary and sufficient condition of optimal policy is obtained. We also prove that the system performance is monotonic with respect to (w.r.t.) the transmission rate and the optimal transmission rate can be either maximal or minimal. That is, the ‘bang-bang’ control is an optimal control. This optimality structure greatly reduces the problem complexity. Furthermore, we develop an iterative algorithm to find the optimal solution. Finally, we conduct the simulation experiments to demonstrate the effectiveness of our approach. We hope our work can shed some insights on solving this complicated optimisation problem.

  7. Merchandise and Replenishment Planning Optimisation for Fashion Retail

    Directory of Open Access Journals (Sweden)

    Raffaele Iannone

    2013-08-01

    Full Text Available The integration among different companies functions, collaborative planning and the elaboration of focused distribution plans are critical to the success of each kind of company working in the complex retail sector. In this contest, the present work proposes the description of a model able to support coordinated strategic choices continually made by Supply Chain (SC actors. The final objective is achievement of the full optimisation of Merchandise & Replenishment Planning phases, identifying the right replenishment quantities and periods. To test the proposed model’s effectiveness, it was applied to an important Italian fashion company in the complex field of fast-fashion, a sector in which promptness is a main competitive leverage and, therefore, the planning cannot exclude the time variable. The passage from a total push strategy, currently used by the company, to a push-pull one, suggested by the model, allowed us not only to estimate a reduction in goods quantities to purchase at the beginning of a sales period (with considerable economic savings, but also elaborate a focused replenishment plan that permits reduction and optimisation of departures from network warehouses to Points of Sale (POS.

  8. Optimising Performance of a Cantilever-type Micro Accelerometer Sensor

    Directory of Open Access Journals (Sweden)

    B.P. Joshi

    2007-05-01

    Full Text Available A technique for optimising performance of cantilever-type micro acceleration sensor hasbeen developed. Performance of a sensor is judged mainly by its sensitivity and bandwidth.Maximising product of these two important parameters of inertial sensors helps to optimise thesensor performance. It is observed that placement of a lumped mass (add-mass on the sensor'sproof-mass helps to control both sensitivity and the first resonant frequency of the cantileverstructure to the designer's choice. Simulation and modelling of various dimensions of rectangularstructures for acceleration sensor with this novel add-mass technique are discussed. CoventorwareMEMSCAD has been used to model, simulate, and carry out FEM analysis. A simple analyticalmodel is discussed to elaborate the mechanics of cantilever-type micro accelerometer. Thecomparison of the results obtained from analytical model and the finite element simulations revealthese to be in good agreement. The advantages of this technique for choosing the two mostimportant sensor parameters (i.e., sensitivity and bandwidth of an inertial sensor are brought out.

  9. Tanlock loop noise reduction using an optimised phase detector

    Science.gov (United States)

    Al-kharji Al-Ali, Omar; Anani, Nader; Al-Qutayri, Mahmoud; Al-Araji, Saleh

    2013-06-01

    This article proposes a time-delay digital tanlock loop (TDTL), which uses a new phase detector (PD) design that is optimised for noise reduction making it amenable for applications that require wide lock range without sacrificing the level of noise immunity. The proposed system uses an improved phase detector design which uses two phase detectors; one PD is used to optimise the noise immunity whilst the other is used to control the acquisition time of the TDTL system. Using the modified phase detector it is possible to reduce the second- and higher-order harmonics by at least 50% compared with the conventional TDTL system. The proposed system was simulated and tested using MATLAB/Simulink using frequency step inputs and inputs corrupted with varying levels of harmonic distortion. A hardware prototype of the system was implemented using a field programmable gate array (FPGA). The practical and simulation results indicate considerable improvement in the noise performance of the proposed system over the conventional TDTL architecture.

  10. Water distribution systems design optimisation using metaheuristics and hyperheuristics

    Directory of Open Access Journals (Sweden)

    DN Raad

    2011-06-01

    Full Text Available The topic of multi-objective water distribution systems (WDS design optimisation using metaheuristics is investigated, comparing numerous modern metaheuristics, including sev- eral multi-objective evolutionary algorithms, an estimation of distribution algorithm and a recent hyperheuristic named AMALGAM (an evolutionary framework for the simultaneous incorporation of multiple metaheuristics, in order to determine which approach is most capa- ble with respect to WDS design optimisation. Novel metaheuristics and variants of existing algorithms are developed, for a total of twenty-three algorithms examined. Testing with re- spect to eight small-to-large-sized WDS benchmarks from the literature reveal that the four top-performing algorithms are mutually non-dominated with respect to the various perfor- mance metrics used. These algorithms are NSGA-II, TAMALGAMJndu , TAMALGAMndu and AMALGAMSndp (the last three being novel variants of AMALGAM. However, when these four algorithms are applied to the design of a very large real-world benchmark, the AMALGAM paradigm outperforms NSGA-II convincingly, with AMALGAMSndp exhibiting the best performance overall.

  11. Track gauge optimisation of railway switches using a genetic algorithm

    Science.gov (United States)

    Pålsson, Björn A.; Nielsen, Jens C. O.

    2012-01-01

    A methodology for the optimisation of a prescribed track gauge variation (gauge widening) in the switch panel of a railway turnout (switch and crossing, S&C) is presented. The aim is to reduce rail profile degradation. A holistic approach is applied, where both routes and travel directions (moves) of traffic in the switch panel are considered simultaneously. The problem is formulated as a multi-objective minimisation problem which is solved using a genetic-type optimisation algorithm which provides a set of Pareto optimal solutions. The dynamic vehicle-turnout interaction is evaluated using a multi-body simulation tool and the energy dissipation in the wheel-rail contacts is used for the assessment of gauge parameters. Two different vehicle models are used, one freight car and one passenger train set, and a stochastic spread in wheel profile and wheel-rail friction coefficient is accounted for. It is found that gauge configurations with a large gauge-widening amplitude for the stock rail on the field side are optimal for both the through and diverging routes, while the results for the gauge side show a larger route dependence. The optimal gauge configurations are observed to be similar for both vehicle types.

  12. Fractures in sport: Optimising their management and outcome.

    Science.gov (United States)

    Robertson, Greg Aj; Wood, Alexander M

    2015-12-18

    Fractures in sport are a specialised cohort of fracture injuries, occurring in a high functioning population, in which the goals are rapid restoration of function and return to play with the minimal symptom profile possible. While the general principles of fracture management, namely accurate fracture reduction, appropriate immobilisation and timely rehabilitation, guide the treatment of these injuries, management of fractures in athletic populations can differ significantly from those in the general population, due to the need to facilitate a rapid return to high demand activities. However, despite fractures comprising up to 10% of all of sporting injuries, dedicated research into the management and outcome of sport-related fractures is limited. In order to assess the optimal methods of treating such injuries, and so allow optimisation of their outcome, the evidence for the management of each specific sport-related fracture type requires assessment and analysis. We present and review the current evidence directing management of fractures in athletes with an aim to promote valid innovative methods and optimise the outcome of such injuries. From this, key recommendations are provided for the management of the common fracture types seen in the athlete. Six case reports are also presented to illustrate the management planning and application of sport-focussed fracture management in the clinical setting.

  13. Optimising Gas Quenching Technology through Modelling of Heat Transfer

    Institute of Scientific and Technical Information of China (English)

    Florent Chaffotte; Linda L(e)fevre; Didier Domergue; Aymeric Goldsteinas; Xavier Doussot; Qingfei Zhang

    2004-01-01

    Gas Quenching represents an environmentally friendly alternative to more commonly-used oil quenching. Yet,the performances of this technology remain limited in terms of cooling rates reached compared to oil quenching. Distortion and process homogeneity also have to be controlled carefully. The efficiency of the gas quenching process fully depends on the heat transfer between the gas and the quenched parts. The goal of this study is the optimisation of the gas quenching process efficiency through a better understanding of the heat transfer phenomena involved. The study has been performed with modelling means and validated by an experimental approach. The configuration of the gas flow has a major influence on the heat transfer phenomena between the gas and the parts. The fluid dynamics modelling approach performed in this study allows to optimise the heat transfer phenomena. New gas quenching processes allowing enhanced gas quenching performance through higher cooling rates can be thereby identified. The new solutions have been validated in experimental and industrial conditions. Results obtained allow to expect significant improvement of high pressure gas quenching technology.

  14. Microstructure stability: Optimisation of 263 Ni-based superalloy

    Directory of Open Access Journals (Sweden)

    Crozet Coraline

    2014-01-01

    Full Text Available To reduce CO2 emissions on coal-fired power plant, A-ultra supercritical (A-USC power plant whose steam conditions exceed 700 °C are being developed. At these elevated temperatures, the use of Ni-base superalloys becomes necessary. In this context and within the European project NextGenPower, focus is made on commercial Nimonic C-263 as a candidate material for turbine rotors. Nimonic C-263 is known to have low sensitivity to segregation, high workability and high weldability which are major properties for the manufacture of large shafts. Long-term creep strength is also required for this application and unfortunately Nimonic C-263 shows η-phase precipitation after long-time exposure between 700 °C–900 °C which is detrimental for long-term creep properties. The composition of Nimonic C-263 was thus optimised to overcome the formation of η-phase. Trial tests were made in order to study the effect of hardening contribution elements on microstructural and mechanical properties. Then, a 500 mm diameter forged rotor was made from optimised 263 alloy and shows promising properties.

  15. Optimisation of a large WWTP thanks to mathematical modelling.

    Science.gov (United States)

    Printemps, C; Baudin, A; Dormoy, T; Zug, M; Vanrolleghem, P A

    2004-01-01

    Better controlling and optimising the plant's processes has become a priority for WWTP (Wastewater Treatment Plant) managers. The main objective of this project is to develop a simplified mathematical tool able to reproduce and anticipate the behaviour of the Tougas WWTP (Nantes, France). This tool is aimed to be used directly by the managers of the site. The mathematical WWTP model was created using the software WEST. This paper describes the studied site and the modelling results obtained during the stage of the model calibration and validation. The good simulation results have allowed to show that despite a first very simple description of the WWTP, the model was able to correctly predict the nitrogen composition (ammonia and nitrate) of the effluent and the daily sludge extraction. Then, a second more detailed configuration of the WWTP was implemented. It has allowed to independently study the behaviour of each of four biological trains. Once this first stage will be completely achieved, the remainder of the study will focus on the operational use of a simplified simulator with the purpose of optimising the Tougas WWTP operation.

  16. Dynamic Programming and Genetic Algorithm for Business Processes Optimisation

    Directory of Open Access Journals (Sweden)

    Mateusz Wibig

    2012-12-01

    Full Text Available There are many business process modelling techniques, which allow to capture features of those processes, but graphical, diagrammatic models seems to be used most in companies and organizations. Although the modelling notations are more and more mature and can be used not only to visualise the process idea but also to implement it in the workflow solution and although modern software allows us to gather a lot of data for analysis purposes, there is still not much commercial used business process optimisation methods. In this paper the scheduling / optimisation method for automatic task scheduling in business processes models is described. The Petri Net model is used, but it can be easily applied to any other modelling notation, where the process is presented as a set of tasks, i.e. BPMN (Business Process Modelling Notation. The method uses Petri Nets’, business processes’ scalability and dynamic programming concept to reduce the necessary computations, by revising only those parts of the model, to which the change was applied.

  17. Radiation protection optimisation techniques and their application in industry

    Energy Technology Data Exchange (ETDEWEB)

    Lefaure, C

    1996-12-31

    Since the International Commission on Radiation Protection (ICRP) recommendation 60, the optimisation principle appears to be the core of the radiation protection system. In practice applying it, means implementing an approach both predictive and evolutionary - that relies essentially on a prudent and responsible state of mind. the formal expression of this process, called optimization procedure, implies and indispensable tool for its implementation: the system of monetary values for the unit of collective dose. During the last few years, feed ALARA principle means that a global work management approach must be adopted, considering together all factors contributing to radiation dose. In the nuclear field, the ALARA approach appears to be more successful when implemented in the framework of a managerial approach through structure ALARA programmes. Outside the nuclear industry it is necessary to clearly define priorities through generic optimisation studies and ALARA audits. At the international level much efforts remain to be done to expand efficiently the ALARA process to internal exposure as well as to public exposure. (author) 2 graphs, 5 figs., 3 tabs.

  18. A Synchronous-Asynchronous Particle Swarm Optimisation Algorithm

    Directory of Open Access Journals (Sweden)

    Nor Azlina Ab Aziz

    2014-01-01

    Full Text Available In the original particle swarm optimisation (PSO algorithm, the particles’ velocities and positions are updated after the whole swarm performance is evaluated. This algorithm is also known as synchronous PSO (S-PSO. The strength of this update method is in the exploitation of the information. Asynchronous update PSO (A-PSO has been proposed as an alternative to S-PSO. A particle in A-PSO updates its velocity and position as soon as its own performance has been evaluated. Hence, particles are updated using partial information, leading to stronger exploration. In this paper, we attempt to improve PSO by merging both update methods to utilise the strengths of both methods. The proposed synchronous-asynchronous PSO (SA-PSO algorithm divides the particles into smaller groups. The best member of a group and the swarm’s best are chosen to lead the search. Members within a group are updated synchronously, while the groups themselves are asynchronously updated. Five well-known unimodal functions, four multimodal functions, and a real world optimisation problem are used to study the performance of SA-PSO, which is compared with the performances of S-PSO and A-PSO. The results are statistically analysed and show that the proposed SA-PSO has performed consistently well.

  19. Optimising Gas Quenching Technology through Modelling of Heat Transfer

    Institute of Scientific and Technical Information of China (English)

    FiorentChaffotte; LindaLefevre; DidierDomergue; AymericGoidsteinas; XavierDoussot; QingfeiZhang

    2004-01-01

    Gas Quenching represents an environmentally friendly alternative to more commonly-used oil quenching. Yet,the performances of this technology remain limited in terms of cooling rates reached compared to oil quenching. Distortion and process homogeneity also have to be controlled carefully. The efficiency of the gas quenching process fully depends on the heat transfer between the gas and the quenched parts. The goal of this study is the optimisation of the gas quenching process efficiency through a better understanding of the heat transfer phenomena involved. The study has been performed with modelling means and validated by an experimental approach. ThE configuration of the gas flow has a major influence on the heat transfer phenomena between the gas and the parts. The fluid dynamics modelling approach performed in this study allows to optimise the heat transfer phenomena. New gas quenching processes allowing enhanced gas quenching performance through higher cooling rates can be thereby identified. The new solutions have been validated in experimental and industrial conditions. Results obtained allow to expect significant improvement of high pressure gas quenching technology.

  20. Loads and loads and loads: The influence of prospective load, retrospective load, and ongoing task load in prospective memory

    Directory of Open Access Journals (Sweden)

    Beat eMeier

    2015-06-01

    Full Text Available In prospective memory tasks different kinds of load can occur. Adding a prospective memory task can impose a load on ongoing task performance. Adding ongoing task load can affect prospective memory performance. The existence of multiple target events increases prospective load and adding complexity to the to-be-remembered action increases retrospective load. In two experiments, we systematically examined the effects of these different types of load on prospective memory performance. Results showed an effect of prospective load on costs in the ongoing task for categorical targets (Experiment 2, but not for specific targets (Experiment 1. Retrospective load and ongoing task load both affected remembering the retrospective component of the prospective memory task. We suggest that prospective load can enhance costs in the ongoing task due to additional monitoring requirements. Retrospective load and ongoing task load seem to impact the division of resources between the ongoing task and retrieval of the retrospective component, which may affect disengagement from the ongoing task. In general, the results demonstrate that the different types of load affect prospective memory differentially.

  1. Extreme Value Predictions for Wave- and Wind-induced Loads on Floating Offshore Wind Turbines using FORM

    DEFF Research Database (Denmark)

    Joensen, Sunvard; Jensen, Jørgen Juncher; Mansour, Alaa E.

    2007-01-01

    The aim of the present paper is to advocate for a very effective stochastic procedure, based on the First Order Reliability Method (FORM), for extreme value predic-tions related to wave induced loads. Due to the efficient optimisation procedures implemented in standard FORM codes and the short du...

  2. SCOOP: A Tool for SymboliC Optimisations Of Probabilistic Processes

    NARCIS (Netherlands)

    Timmer, Mark; Palamidessi, C.; Riska, A.

    2011-01-01

    This paper presents SCOOP: a tool that symbolically optimises process-algebraic specifications of probabilistic processes. It takes specifications in the prCRL language (combining data and probabilities), which are linearised first to an intermediate format: the LPPE. On this format, optimisations s

  3. Asynchronous Adaptive Optimisation for Generic Data-Parallel Array Programming and Beyond

    NARCIS (Netherlands)

    Grelck, C.

    2011-01-01

    We present the concept of an adaptive compiler optimisation framework for the functional array programming language SaC, Single Assignment C. SaC advocates shape- and rank-generic programming with multidimensional arrays. A sophisticated, highly optimising compiler technology nonetheless achieves co

  4. Asynchronous Adaptive Optimisation for Generic Data-Parallel Array Programming and Beyond

    NARCIS (Netherlands)

    Grelck, C.

    2011-01-01

    We present the concept of an adaptive compiler optimisation framework for the functional array programming language SaC, Single Assignment C. SaC advocates shape- and rank-generic programming with multidimensional arrays. A sophisticated, highly optimising compiler technology nonetheless achieves co

  5. Optimisation of the $VH$ to $b\\bar{b} + X$ Selection

    CERN Document Server

    Wilk, Fabian

    2013-01-01

    This report presents results from two separated, yet related studies both using truth data: First a cut optimisation study and its results are presented. This study aims to provide a numerically optimised set of cuts for the current $8\\, \\mathrm{TeV}$ and the upcoming $14 \\, \\mathrm{TeV}$ analysis of the $WH \\to l\

  6. Optimisation of electrical system for offshore wind farms via genetic algorithm

    DEFF Research Database (Denmark)

    Chen, Zhe; Zhao, Menghua; Blaabjerg, Frede

    2009-01-01

    An optimisation platform based on genetic algorithm (GA) is presented, where the main components of a wind farm and key technical specifications are used as input parameters and the electrical system design of the wind farm is optimised in terms of both production cost and system reliability...

  7. Design of Circularly-Polarised, Crossed Drooping Dipole, Phased Array Antenna Using Genetic Algorithm Optimisation

    DEFF Research Database (Denmark)

    Larsen, Niels Vesterdal

    2007-01-01

    A printed drooping dipole array is designed and constructed. The design is based on a genetic algorithm optimisation procedure used in conjunction with the software programme AWAS. By optimising the array G/T for specific combinations of scan angles and frequencies an optimum design is obtained...

  8. Optimal Energy Consumption in Refrigeration Systems - Modelling and Non-Convex Optimisation

    DEFF Research Database (Denmark)

    Hovgaard, Tobias Gybel; Larsen, Lars F. S.; Skovrup, Morten J.

    2012-01-01

    that is somewhat more efficient than general purpose optimisation algorithms for NMPC and still near to optimal. Since the non-convex cost function has multiple extrema, standard methods for optimisation cannot be directly applied. A qualitative analysis of the system's constraints is presented and a unique...

  9. Design of Circularly-Polarised, Crossed Drooping Dipole, Phased Array Antenna Using Genetic Algorithm Optimisation

    DEFF Research Database (Denmark)

    Larsen, Niels Vesterdal

    2007-01-01

    A printed drooping dipole array is designed and constructed. The design is based on a genetic algorithm optimisation procedure used in conjunction with the software programme AWAS. By optimising the array G/T for specific combinations of scan angles and frequencies an optimum design is obtained...

  10. Ice load on offshore wind turbine foundations; Ice load on offshore wind turbine foundations

    Energy Technology Data Exchange (ETDEWEB)

    Voelund, P.; Joergensen, L.B. [Energi E2, Koebenhavn (Denmark); Gravesen, H.; Soerensen, S.L. [Carl Bro, Glostrup (Denmark); Pedersen, B.; Lorenz, R.S.; Miller, R.; Oestergaard, S.; Riber, H.J. [LIC Engineering, Hellerup (Denmark); Pedersen, J.; Gjerding, J.B. [Tripod, Soeborg (DK)

    2003-12-01

    Ice loading on wind turbine foundations in the inner Danish seas and straits is a design load. Relative conservative design requirement/guidelines have so far been used for prediction of ice loads. The aim of the present project is to improve knowledge of ice loads on wind turbine foundations and to identify improved prediction methods and possible ways of optimising the foundation design With respect to ice loads. Conference presentations and papers of ice theory have been collected and studied. International state of the art ice models and theories are described in the project documents and tested. Models have been made to investigate and compare predicted results with scaled model tests. Scaled model tests of conical and cylindrical foundations have been made at NRC at Canada. The test stand and tests are presented along with analysis of the data. To reduce ice loading on structures in the inner Danish seas and straits conical foundations are used. The conical foundation will reduce the ice loads, but slightly increase the wave load - the consequences have been investigated. Main activities of the project cover: (1) Review of publicly available literature on ice ridges. (2) Ice growth modelling in the open sea as well as in sheltered sea. (3) Modelling of ice floe interaction with an offshore wind turbine farm. (4) Modelling of structural response of a wind turbine to ice loads. (5) Implementation and test of two semi-empincal dynamic ice load models. (6) Modelling of ice load generated fatigue damage. (7) Review of the ice load design requirements in the inner Danish seas and straits. (8) Test bed measurements at NRC, Canada, of ice loads on sale-models of cylindrical, 55 deg. C and 65 deg. C conical and double conical foundations. (9) Analysis of these scaled model tests. (10) Generation of 10 min time series from short term scaled model tests. (11) Detailed design requirements for upwards and downwards bending cones. (12) Design requirements for a double

  11. Using response surface methodology in optimisation of biodiesel production via alkali catalysed transesterification of waste cooking oil

    CSIR Research Space (South Africa)

    Naidoo, R

    2016-03-01

    Full Text Available The report focuses on optimisation of alkali catalysis as a process for producing biodiesel from waste cooking oils. Biodiesel production parameters that were optimised were methanol to oil ratio, catalyst concentration, reaction temperature...

  12. Towards an unbiased metabolic profiling of protozoan parasites : optimisation of a Leishmania sampling protocol for HILIC-orbitrap analysis

    NARCIS (Netherlands)

    t'Kindt, Ruben; Jankevics, Andris; Scheltema, Richard A.; Zheng, Liang; Watson, David G.; Dujardin, Jean-Claude; Breitling, Rainer; Coombs, Graham H.; Decuypere, Saskia; Kindt, Ruben t’

    2010-01-01

    Comparative metabolomics of Leishmania species requires the simultaneous identification and quantification of a large number of intracellular metabolites. Here, we describe the optimisation of a comprehensive metabolite extraction protocol for Leishmania parasites and the subsequent optimisation of

  13. 采用钢结构加层的混凝土框架结构的侧向力分布比较%Load Pattern Compared of RC Frame Structures after Steel Adding Storey in Pushover Analysis

    Institute of Scientific and Technical Information of China (English)

    林敏

    2012-01-01

    Pushover analysis is a simplified method for structure seismic evaluation,which is extensively used gradually,and is recommended by the new national code of seismic design of buildings.The load pattern selection is one of the critical issues in pushover analysis,especially to the RC frame after steel adding storey,for the distribution of lateral force Pushover analysis result is more significant impact.Based on the three groups of six types of framework,different lateral force distribution was selected for pushover analysis,and the nonlinear time-history analysis results were compared.The results show that,for RC frame structure after steel adding storey directly,the results obtained of different lateral force distribution of pushover are different,and the time-history analysis results of deviation bigger also.%Pushover分析方法是逐渐得到广泛应用的一种评估结构抗震性能的简化方法,已被引入我国新的建筑结构抗震设计规范。侧向力分布的选取是结构Pushover分析中的一个关键问题,尤其是对于混凝土框架直接加层钢框架结构,由于上下层间刚度比差异较大,侧向力分布对其Pushover分析的结果影响更为显著。文章通过对3组共6榀加层框架,选取不同的侧向力分布进行了Pushover分析,并与非线性时程分析结果进行了比较。比较结果表明,对于混凝土框架结构直接加层钢框架结构,不同的侧向力分布得到的Pushover分析结果差异较大,与时程分析结果的偏差也较大。

  14. Simulation and optimisation modelling approach for operation of the Hoa Binh Reservoir, Vietnam

    DEFF Research Database (Denmark)

    Ngo, Long le; Madsen, Henrik; Rosbjerg, Dan

    2007-01-01

    Hoa Binh, the largest reservoir in Vietnam, plays an important role in flood control for the Red River delta and hydropower generation. Due to its multi-purpose character, conflicts and disputes in operating the reservoir have been ongoing since its construction, particularly in the flood season......, the hydro-meteorological conditions, and the time of the year. A heuristic global optimisation tool, the shuffled complex evolution (SCE) algorithm, is adopted for optimising the reservoir operation. The optimisation puts focus on the trade-off between flood control and hydropower generation for the Hoa....... This paper proposes to optimise the control strategies for the Hoa Binh reservoir operation by applying a combination of simulation and optimisation models. The control strategies are set up in the MIKE 11 simulation model to guide the releases of the reservoir system according to the current storage level...

  15. Large scale three-dimensional topology optimisation of heat sinks cooled by natural convection

    CERN Document Server

    Alexandersen, Joe; Aage, Niels

    2015-01-01

    This work presents the application of density-based topology optimisation to the design of three-dimensional heat sinks cooled by natural convection. The governing equations are the steady-state incompressible Navier-Stokes equations coupled to the thermal convection-diffusion equation through the Bousinessq approximation. The fully coupled non-linear multiphysics system is solved using stabilised trilinear equal-order finite elements in a parallel framework allowing for the optimisation of large scale problems with order of 40-330 million state degrees of freedom. The flow is assumed to be laminar and several optimised designs are presented for Grashof numbers between $10^3$ and $10^6$. Interestingly, it is observed that the number of branches in the optimised design increases with increasing Grashof numbers, which is opposite to two-dimensional optimised designs.

  16. The Influence of Lateral Load Patterns on the Results of Static Pushover Analysis in High-rise Building%侧向荷载分布方式对高层建筑静力弹塑性分析结果的影响

    Institute of Scientific and Technical Information of China (English)

    杨万

    2014-01-01

    Pushover方法作为一种建筑结构弹塑性地震响应的简化近似计算方法和抗震性能评价方法已得到广泛应用。但由于其理论基础不严密,其准确性需要给予必要确认,同时其适用性也受到一定的限值。就侧向荷载分布方式,对静力弹塑性pushover分析结果的影响进行了研究。用四种不同的侧向荷载分布方式,对一栋24层的高层结构进行了分析。分析结果表明:在不同侧向荷载分布方式作用下, pushover分析结果相差很大。就分析结果而言,选择实时模态的荷载分布方式更为合理。%The nonlinear static pushover analysis procedure is now widely used as a simple method to estimate the inelastic seismic response for building structures. However, the accuracy of the method still needs to be validated because of the inherent limitations in its theory. Besides, there are some limitations on the application of this method. In this paper, the influence of lateral load patterns on the results of static pushover analysis has been studied. The static pushover analysis with four different lateral load patterns was applied to a tall building of 24 stories. It is demonstrated that the analysis results may vary significantly under different lateral load patterns. In terms of the analysis results, feasibility load pattern is more reasonable.

  17. Electrical load detection aparatus

    DEFF Research Database (Denmark)

    2010-01-01

    A load detection technique for a load comprising multiple frequency-dependant sub-loads comprises measuring a representation of the impedance characteristic of the load; providing stored representations of a multiplicity of impedance characteristics of the load; each one of the stored representat...

  18. Contact analysis and load distribution of double-envelop hourglassworm gearing affected by errors and load

    Institute of Scientific and Technical Information of China (English)

    XU Wujiao; QIN Datong; SHI Wankai

    2003-01-01

    An approach for the contact analysis and load distribution of double-envelop hourglass worm gearing is presented,which is based on a 3-D elastic contact finite element method (FEM) model that 3ccommodates the influence of errors and load.As compared with existing tooth contact analysis model that assumes rigidity for the contacting surfaces, the proposed model provides a more realistic analysis on the contact patterns, the distribution of contact load and transmission errors. It is also capable of exploring the influence of different errors on meshing performances, the contact deformation, the shift of the contact zone and load share among the meshing tooth-pairs under different load.

  19. Energy efficiency analysis of reconfigured distribution system for practical loads

    Directory of Open Access Journals (Sweden)

    Pawan Kumar

    2016-09-01

    Full Text Available In deregulated rate structure, the performance evaluation of distribution system for energy efficiency includes; loss minimization, improved power quality, loadability limit, reliability and availability of supply. Energy efficiency changes with the variation in loading pattern and the load behaviour. Further, the nature of load at each node is not explicitly of any one type rather their characteristics depend upon the node voltages. In most cases, load is assumed to be constant power (real and reactive. In this paper voltage dependent practical loads are represented with composite load model and the energy efficiency performance of distribution system for practical loads is evaluated in different configurations of 33-node system.

  20. Analysis and Optimisation of Hierarchically Scheduled Multiprocessor Embedded Systems

    DEFF Research Database (Denmark)

    Pop, Traian; Pop, Paul; Eles, Petru;

    2008-01-01

    , they are organised in a hierarchy. In this paper, we first develop a holistic scheduling and schedulability analysis that determines the timing properties of a hierarchically scheduled system. Second, we address design problems that are characteristic to such hierarchically scheduled systems: assignment......We present an approach to the analysis and optimisation of heterogeneous multiprocessor embedded systems. The systems are heterogeneous not only in terms of hardware components, but also in terms of communication protocols and scheduling policies. When several scheduling policies share a resource...... of scheduling policies to tasks, mapping of tasks to hardware components, and the scheduling of the activities. We also present several algorithms for solving these problems. Our heuristics are able to find schedulable implementations under limited resources, achieving an efficient utilisation of the system...

  1. Optimisation of LHCb Applications for Multi- and Manycore Job Submission

    CERN Document Server

    Rauschmayr, Nathalie; Graciani Diaz, Ricardo; Charpentier, Philippe

    The Worldwide LHC Computing Grid (WLCG) is the largest Computing Grid and is used by all Large Hadron Collider experiments in order to process their recorded data. It provides approximately 400k cores and storages. Nowadays, most of the resources consist of multi- and manycore processors. Conditions at the Large Hadron Collider experiments will change and much larger workloads and jobs consuming more memory are expected in future. This has lead to a shift of paradigm which focuses on executing jobs as multiprocessor tasks in order to use multi- and manycore processors more efficiently. All experiments at CERN are currently investigating how such computing resources can be used more efficiently in terms of memory requirements and handling of concurrency. Until now, there are still many unsolved issues regarding software, scheduling, CPU accounting, task queues, which need to be solved by grid sites and experiments. This thesis develops a systematic approach to optimise the software of the LHCb experiment fo...

  2. Optimisation de contrôleurs par essaim particulaire

    OpenAIRE

    Fix, Jérémy; Geist, Matthieu

    2012-01-01

    http://cap2012.loria.fr/pub/Papers/10.pdf; National audience; Trouver des contrôleurs optimaux pour des systèmes stochastiques est un problème particulièrement difficile abordé dans les communautés d'apprentissage par renforcement et de contrôle optimal. Le paradigme classique employé pour résoudre ces problèmes est celui des processus décisionnel de Markov. Néanmoins, le problème d'optimisation qui en découle peut être difficile à résoudre. Dans ce papier, nous explorons l'utilisation de l'o...

  3. Optimised to Fail: Card Readers for Online Banking

    Science.gov (United States)

    Drimer, Saar; Murdoch, Steven J.; Anderson, Ross

    The Chip Authentication Programme (CAP) has been introduced by banks in Europe to deal with the soaring losses due to online banking fraud. A handheld reader is used together with the customer’s debit card to generate one-time codes for both login and transaction authentication. The CAP protocol is not public, and was rolled out without any public scrutiny. We reverse engineered the UK variant of card readers and smart cards and here provide the first public description of the protocol. We found numerous weaknesses that are due to design errors such as reusing authentication tokens, overloading data semantics, and failing to ensure freshness of responses. The overall strategic error was excessive optimisation. There are also policy implications. The move from signature to PIN for authorising point-of-sale transactions shifted liability from banks to customers; CAP introduces the same problem for online banking. It may also expose customers to physical harm.

  4. Optimised Iteration in Coupled Monte Carlo - Thermal-Hydraulics Calculations

    Science.gov (United States)

    Hoogenboom, J. Eduard; Dufek, Jan

    2014-06-01

    This paper describes an optimised iteration scheme for the number of neutron histories and the relaxation factor in successive iterations of coupled Monte Carlo and thermal-hydraulic reactor calculations based on the stochastic iteration method. The scheme results in an increasing number of neutron histories for the Monte Carlo calculation in successive iteration steps and a decreasing relaxation factor for the spatial power distribution to be used as input to the thermal-hydraulics calculation. The theoretical basis is discussed in detail and practical consequences of the scheme are shown, among which a nearly linear increase per iteration of the number of cycles in the Monte Carlo calculation. The scheme is demonstrated for a full PWR type fuel assembly. Results are shown for the axial power distribution during several iteration steps. A few alternative iteration method are also tested and it is concluded that the presented iteration method is near optimal.

  5. A Metric and Optimisation Scheme for Microlens Planet Searches

    CERN Document Server

    Horne, Keith; Tsapras, Yianni

    2009-01-01

    OGLE III and MOA II are discovering 600-1000 Galactic Bulge microlens events each year. This stretches the resources available for intensive follow-up monitoring of the lightcurves in search of anomalies caused by planets near the lens stars. We advocate optimizing microlens planet searches by using an automatic prioritization algorithm based on the planet detection zone area probed by each new data point. This optimization scheme takes account of the telescope and detector characteristics, observing overheads, sky conditions, and the time available for observing on each night. The predicted brightness and magnification of each microlens target is estimated by fitting to available data points. The optimisation scheme then yields a decision on which targets to observe and which to skip, and a recommended exposure time for each target, designed to maximize the planet detection capability of the observations. The optimal strategy maximizes detection of planet anomalies, and must be coupled with rapid data reduct...

  6. Optimisation of Resource Scheduling in VCIM Systems Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Son Duy Dao

    2012-11-01

    Full Text Available The concept of Virtual Computer-Integrated Manufacturing (VCIM has been proposed for one and a half decade with purpose of overcoming the limitation of traditional Computer-Integrated Manufacturing (CIM as it only works within an enterprise. VCIM system is a promising solution for enterprises to survive in the globally competitive market because it can exploit effectively locally as well as globally distributed resources. In this paper, a Genetic Algorithm (GA based approach for optimising resource scheduling in the VCIM system is proposed. Firstly, based on the latest concept of VCIM system, a class of resource scheduling problems in the system is modelled by using agent-based approach. Secondly, GA with new strategies of handling constraint, chromosome encoding, crossover and mutation is developed to search for optimal solution for the problem. Finally, a case study is given to demonstrate the robustness of the proposed approach.

  7. Analysis and Optimisation of Pulse Dynamics for Magnetic Stimulation

    CERN Document Server

    Goetz, Stefan M; Gerhofer, Manuel G; Weyh, Thomas; Herzog, Hans-Georg

    2011-01-01

    Magnetic stimulation is a standard tool in brain research and many fields of neurology, as well as psychiatry. From a physical perspective, one key aspect of this method is the inefficiency of available setups. Whereas the spatial field properties have been studied rather intensively with coil designs, the dynamics have been neglected almost completely for a long time. Instead, the devices and their technology defined the waveform. Here, an analysis of the waveform space is performed. Based on these data, an appropriate optimisation approach is outlined which makes use of a modern nonlinear axon description of a mammalian motor nerve. The approach is based on a hybrid global-local method; different coordinate systems for describing the continuous waveforms in a limited parameter space are defined for sufficient stability. The results of the numeric setup suggest that there is plenty of room for waveforms with higher efficiency than the traditional shapes. One class of such pulses is analysed further. Although...

  8. Pre-Industry-Optimisation of the Laser Welding Process

    DEFF Research Database (Denmark)

    Gong, Hui

    This dissertation documents the investigations into on-line monitoring the CO2 laser welding process and optimising the process parameters for achieving high quality welds. The requirements for realisation of an on-line control system are, first of all, a clear understanding of the dynamic...... phenomena of the laser welding process including the behaviour of the keyhole and plume, and the correlation between the adjustable process parameters: laser power, welding speed, focal point position, gas parameters etc. and the characteristics describing the quality of the weld: seam depth and width......, porosity etc. Secondly, a reliable monitoring system for sensing the laser-induced plasma and plume emission and detecting weld defects and process parameter deviations from the optimum conditions. Finally, an efficient control system with a fast signal processor and a precise feed-back controller...

  9. Analysis and Optimisation of Carcass Production for Flexible Pipes

    DEFF Research Database (Denmark)

    Nielsen, Peter Søe

    structure that provides mechanical and collapse strength for the flexible pipe. The manufacturing process of carcass is a combination of roll forming stainless steel strips and helical winding the profiles around a mandrel interlocking the profiles with themselves. The focus of the present project...... is the analysis and optimisation of the carcass manufacturing process by means of a fundamental investigation in the fields of formability, failure modes / mechanisms, Finite Element Analysis (FEA), simulative testing and tribology. A study of failure mechanisms in carcass production is performed by being present...... strip thickness deep. Simulative tribo-testing in the strip-reduction-test showed that biodegradable rapeseed oil is an acceptable lubricant for the carcass process. Testing of two lean duplex stainless steel surfaces showed that a EN 2E brushed surface had better lubricant entrapment capabilities than...

  10. Dose evaluation from multiple detector outputs using convex optimisation.

    Science.gov (United States)

    Hashimoto, Makoto; Iimoto, Takeshi; Kosako, Toshiso

    2011-07-01

    A dose evaluation using multiple radiation detectors can be improved by the convex optimisation method. It enables flexible dose evaluation corresponding to the actual radiation energy spectrum. An application to the neutron ambient dose equivalent evaluation is investigated using a mixed-gas proportional counter. The convex derives the certain neutron ambient dose with certain width corresponding to the true neutron energy spectrum. The range of the evaluated dose is comparable to the error of conventional neutron dose measurement equipments. An application to the neutron individual dose equivalent measurement is also investigated. Convexes of particular dosemeter combinations evaluate the individual dose equivalent better than the dose evaluation of a single dosemeter. The combinations of dosemeters with high orthogonality of their response characteristics tend to provide a good suitability for dose evaluation.

  11. Optimisation of geometrical ratchets for spin-current amplification

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Ranjdar M. [Department of Electronics, University of York, Heslington, York YO10 5DD (United Kingdom); Vick, Andrew J. [Department of Electronics, University of York, Heslington, York YO10 5DD (United Kingdom); Department of Physics, University of York, York YO10 5DD (United Kingdom); Murphy, Benedict A. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Hirohata, Atsufumi, E-mail: atsufumi.hirohata@york.ac.uk [Department of Electronics, University of York, Heslington, York YO10 5DD (United Kingdom); PRESTO, Japan Science and Technology Agency, Kawaguchi 332-0012 (Japan)

    2015-05-07

    A two-dimensional model is used to study the geometrical effects of a nonmagnetic (NM) nanowire upon a spin-polarised electron current in a lateral spin-valve structure. We found that the implemented ratchet shapes at the centre of the NM have a crucial effect on the diffusive rate for up- and down-spin electrons along the wire, which leads to the amplification of non-local spin-current signals. By using our simple model, the geometries have been optimised. The calculated spin-current signals are in good qualitative agreement with our recent experimental results [Abdullah et al., J. Phys. D: Appl. Phys. 47, 482001(FTC) (2014)]. Our model may be very useful to evaluate such a geometrical effect on spin-polarised electron transport.

  12. X-ray energy optimisation in computed microtomography.

    Science.gov (United States)

    Spanne, P

    1989-06-01

    Expressions describing the absorbed dose and the number of incident photons necessary for the detection of a contrasting detail in x-ray transmission CT imaging of a circular phantom are derived as functions of the linear attenuation coefficients of the materials comprising the object and the detail. A shell of a different material can be included to allow simulation of CT imaging of the skulls of small laboratory animals. The equations are used to estimate the optimum photon energy in x-ray transmission computed microtomography. The optimum energy depends on whether the number of incident photons or the absorbed dose at a point in the object is minimised. For a water object of 300 mm diameter the two optimisation criteria yield optimum photon energies differing by an order of magnitude.

  13. Symmetrisation schemes for global optimisation of atomic clusters.

    Science.gov (United States)

    Oakley, Mark T; Johnston, Roy L; Wales, David J

    2013-03-21

    Locating the global minima of atomic and molecular clusters can be a difficult optimisation problem. Here we report benchmarks for procedures that exploit approximate symmetry. This strategy was implemented in the GMIN program following a theoretical analysis, which explained why high-symmetry structures are more likely to have particularly high or particularly low energy. The analysis, and the corresponding algorithms, allow for approximate point group symmetry, and can be combined with basin-hopping and genetic algorithms. We report results for 38-, 75-, and 98-atom Lennard-Jones clusters, which are all multiple-funnel systems. Exploiting approximate symmetry reduces the mean time taken to locate the global minimum by up to two orders of magnitude, with smaller improvements in efficiency for LJ(55) and LJ(74), which correspond to simpler single-funnel energy landscapes.

  14. Optimisation-Based Solution Methods for Set Partitioning Models

    DEFF Research Database (Denmark)

    Rasmussen, Matias Sevel

    The scheduling of crew, i.e. the construction of work schedules for crew members, is often not a trivial task, but a complex puzzle. The task is complicated by rules, restrictions, and preferences. Therefore, manual solutions as well as solutions from standard software packages are not always su......_cient with respect to solution quality and solution time. Enhancement of the overall solution quality as well as the solution time can be of vital importance to many organisations. The _elds of operations research and mathematical optimisation deal with mathematical modelling of di_cult scheduling problems (among...... other topics). The _elds also deal with the development of sophisticated solution methods for these mathematical models. This thesis describes the set partitioning model which has been widely used for modelling crew scheduling problems. Integer properties for the set partitioning model are shown...

  15. Kinetic model of metabolic network for xiamenmycin biosynthetic optimisation.

    Science.gov (United States)

    Xu, Min-juan; Chen, Yong-cong; Xu, Jun; Ao, Ping; Zhu, Xiao-mei

    2016-02-01

    Xiamenmycins, a series of prenylated benzopyran compounds with anti-fibrotic bioactivities, were isolated from a mangrove-derived Streptomyces xiamenensis. To fulfil the requirements of pharmaceutical investigations, a high production of xiamenmycin is needed. In this study, the authors present a kinetic metabolic model to evaluate fluxes in an engineered Streptomyces lividans with xiamenmycin-oriented genetic modification based on generic enzymatic rate equations and stability constraints. Lyapunov function was used for a viability optimisation. From their kinetic model, the flux distributions for the engineered S. lividans fed on glucose and glycerol as carbon sources were calculated. They found that if the bacterium can utilise glucose simultaneously with glycerol, xiamenmycin production can be enhanced by 40% theoretically, while maintaining the same growth rate. Glycerol may increase the flux for phosphoenolpyruvate synthesis without interfering citric acid cycle. They therefore believe this study demonstrates a possible new direction for bioengineering of S. lividans.

  16. Optimising, generalising and integrating educational practice using neuroscience

    Science.gov (United States)

    Colvin, Robert

    2016-07-01

    Practical collaboration at the intersection of education and neuroscience research is difficult because the combined discipline encompasses both the activity of microscopic neurons and the complex social interactions of teachers and students in a classroom. Taking a pragmatic view, this paper discusses three education objectives to which neuroscience can be effectively applied: optimising, generalising and integrating instructional techniques. These objectives are characterised by: (1) being of practical importance; (2) building on existing education and cognitive research; and (3) being infeasible to address based on behavioural experiments alone. The focus of the neuroscientific aspect of collaborative research should be on the activity of the brain before, during and after learning a task, as opposed to performance of a task. The objectives are informed by literature that highlights possible pitfalls with educational neuroscience research, and are described with respect to the static and dynamic aspects of brain physiology that can be measured by current technology.

  17. Optimisation of a parallel ocean general circulation model

    Directory of Open Access Journals (Sweden)

    M. I. Beare

    Full Text Available This paper presents the development of a general-purpose parallel ocean circulation model, for use on a wide range of computer platforms, from traditional scalar machines to workstation clusters and massively parallel processors. Parallelism is provided, as a modular option, via high-level message-passing routines, thus hiding the technical intricacies from the user. An initial implementation highlights that the parallel efficiency of the model is adversely affected by a number of factors, for which optimisations are discussed and implemented. The resulting ocean code is portable and, in particular, allows science to be achieved on local workstations that could otherwise only be undertaken on state-of-the-art supercomputers.

  18. Optimisation of assembly scheduling in VCIM systems using genetic algorithm

    Science.gov (United States)

    Dao, Son Duy; Abhary, Kazem; Marian, Romeo

    2017-01-01

    Assembly plays an important role in any production system as it constitutes a significant portion of the lead time and cost of a product. Virtual computer-integrated manufacturing (VCIM) system is a modern production system being conceptually developed to extend the application of traditional computer-integrated manufacturing (CIM) system to global level. Assembly scheduling in VCIM systems is quite different from one in traditional production systems because of the difference in the working principles of the two systems. In this article, the assembly scheduling problem in VCIM systems is modeled and then an integrated approach based on genetic algorithm (GA) is proposed to search for a global optimised solution to the problem. Because of dynamic nature of the scheduling problem, a novel GA with unique chromosome representation and modified genetic operations is developed herein. Robustness of the proposed approach is verified by a numerical example.

  19. Target Loading from a Submerged Explosion

    Directory of Open Access Journals (Sweden)

    Andrew Wardlaw

    2010-01-01

    Full Text Available The pressure on a flat plate suspended over a submerged detonation is measured and simulated. Calculation and experiment are in relatively good agreement, although there is variation in experimental results and simulations are sensitive, near the centerline, to the computational details. This sensitivity is linked to the instability of the accelerating plume, typical of a Richtmyer-Meshkov instability. The plate loading features an initial force at plate center, followed by an expanding circular loading pattern. The initial load is due to plume impact, while the circular load arises from the impact of water transported up the edges of the explosion cavity.

  20. Optimisation of Sintering Factors of Titanium Foams Using Taguchi Method

    Directory of Open Access Journals (Sweden)

    S. Ahmad

    2010-06-01

    Full Text Available Metal foams have the potential to be used in the production of bipolar plates in Polymer Electron Membrane Fuel Cells (PEMFC. In this paper, pure titanium was used to prepare titanium foam using the slurry method. The electrical conductivity is the most important parameter to be considered in the production of good bipolar plates. To achieve a high conductivity of the titanium foam, the effects of various parameters including temperature, time profile and composition have to be characterised and optimised. This paper reports the use of the Taguchi method in optimising the processing parameters of pure titanium foams. The effects of four sintering factors, namely, composition, sintering temperature, heating rate and soaking time on the electrical conductivity has been studied. The titanium slurry was prepared by mixing titanium alloy powder, polyethylene glycol (PEG, methylcellulose and water. Polyurethane (PU foams were then impregnated into the slurry and later dried at room temperature. These were next sintered in a high temperature vacuum furnace. The various factors were assigned to an L9 orthogonal array. From the Analysis of Variance (ANOVA, the composition of titanium powder has the highest percentage of contribution (24.51 to the electrical conductivity followed by the heating rate (10.29. The optimum electrical conductivity was found to be 1336.227 ± 240.61 S/cm-1 for this titanium foam. It was achieved with a 70% composition of titanium, sintering temperature of 1200oC, a heating rate of 0.5oC/min and 2 hours soaking time. Confirmatory experiments have produced results that lay within the 90% confidence interval.