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Sample records for iterative feedback tuning

  1. Iterative Feedback Tuning in district heating systems; Iterative Feedback Tuning i vaermeproduktionsanlaeggningar

    Energy Technology Data Exchange (ETDEWEB)

    Raaberg, Martin; Velut, Stephane; Bari, Siavosh Amanat

    2010-10-15

    The project goal is to evaluate and describe how Iterative Feedback Tuning (IFT) can be used to tune controllers in the typical control loops in heat- and power plants. There are only a few practical studies carried out for IFT and they are not really relevant for power and heat processes. It is the practical problems in implementing the IFT and the result of trimming that is the focus of this project. The project will start with theoretical studies of the IFT-method, then realization and simple simulations in scilab. The IFT equations are then implemented in Freelance 2000, an ABB control system, for practical tests on a SISO- and a MIMO-process. By performing reproducible experiments on the process and analyze the results IFT can adjust the controller parameters to minimize a cost function that represents the control goal. The project selected for SISO experiments a pressure controller in an oil transportation system. By controlling the valve position of a control valve for the reversal to the supply tank, the pressure in the oil transport system is regulated. A disturbance in oil pressure can be achieved by changing the position of a valve that lets oil through to the day tank. The selected MIMO-process is a pre-heater in a degassing process. In this process, a valve on the secondary side is utilized to control the flow in the secondary system. A valve on the primary side is utilized to control the district heating water flow through the heat exchanger to control the temperature on the secondary side. An increased secondary flow increases the heat demand and thus requiring an increase in primary flow to maintain the secondary side outlet temperature. This is the cross-coupling responsible for why it is an advantage to consider the process as multi-variable. Using the IFT method, the two original PID-controllers and a feed-forward controller is tuned simultaneously. IFT-method was difficult to implement but worked well in both simulations and in real processes

  2. Iterative feedback tuning of wind turbine controllers

    NARCIS (Netherlands)

    van Solingen, E.; Mulders, S.P.; van Wingerden, J.W.

    2017-01-01

    Traditionally, wind turbine controllers are designed using first principles or linearized or identified models. The aim of this paper is to show that with an automated, online, and model-free tuning strategy, wind turbine control performance can be significantly increased. For this purpose,

  3. A Design Algorithm using External Perturbation to Improve Iterative Feedback Tuning Convergence

    DEFF Research Database (Denmark)

    Huusom, Jakob Kjøbsted; Hjalmarsson, Håkan; Poulsen, Niels Kjølstad

    2011-01-01

    Iterative Feedback Tuning constitutes an attractive control loop tuning method for processes in the absence of process insight. It is a purely data driven approach for optimization of the loop performance. The standard formulation ensures an unbiased estimate of the loop performance cost function...... information content by introducing an optimal perturbation signal in the tuning algorithm. The theoretical analysis is supported by a simulation example where the proposed method is compared to an existing method for acceleration of the convergence by use of optimal prefilters....

  4. Simultaneous gains tuning in boiler/turbine PID-based controller clusters using iterative feedback tuning methodology.

    Science.gov (United States)

    Zhang, Shu; Taft, Cyrus W; Bentsman, Joseph; Hussey, Aaron; Petrus, Bryan

    2012-09-01

    Tuning a complex multi-loop PID based control system requires considerable experience. In today's power industry the number of available qualified tuners is dwindling and there is a great need for better tuning tools to maintain and improve the performance of complex multivariable processes. Multi-loop PID tuning is the procedure for the online tuning of a cluster of PID controllers operating in a closed loop with a multivariable process. This paper presents the first application of the simultaneous tuning technique to the multi-input-multi-output (MIMO) PID based nonlinear controller in the power plant control context, with the closed-loop system consisting of a MIMO nonlinear boiler/turbine model and a nonlinear cluster of six PID-type controllers. Although simplified, the dynamics and cross-coupling of the process and the PID cluster are similar to those used in a real power plant. The particular technique selected, iterative feedback tuning (IFT), utilizes the linearized version of the PID cluster for signal conditioning, but the data collection and tuning is carried out on the full nonlinear closed-loop system. Based on the figure of merit for the control system performance, the IFT is shown to deliver performance favorably comparable to that attained through the empirical tuning carried out by an experienced control engineer. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  5. Iterative Controller Tuning for Process with Fold Bifurcations

    DEFF Research Database (Denmark)

    Huusom, Jakob Kjøbsted; Poulsen, Niels Kjølstad; Jørgensen, Sten Bay

    2007-01-01

    Processes involving fold bifurcation are notoriously difficult to control in the vicinity of the fold where most often optimal productivity is achieved . In cases with limited process insight a model based control synthesis is not possible. This paper uses a data driven approach with an improved...... version of iterative feedback tuning to optimizing a closed loop performance criterion, as a systematic tool for tuning process with fold bifurcations....

  6. Feedback reliability calculation for an iterative block decision feedback equalizer

    OpenAIRE

    Huang, G; Nix, AR; Armour, SMD

    2009-01-01

    A new class of iterative block decision feedback equalizer (IB-DFE) was pioneered by Chan and Benvenuto. Unlike the conventional DFE, the IB-DFE is optimized according to the reliability of the feedback (FB) symbols. Since the use of the training sequence (TS) for feedback reliability (FBR) estimation lowers the bandwidth efficiency, FBR estimation without the need for additional TS is of considerable interest. However, prior FBR estimation is limited in the literature to uncoded M-ary phases...

  7. Design of fast tuning elements for the ITER ICH system

    International Nuclear Information System (INIS)

    Swain, D.W.; Goulding, R.H.

    1996-05-01

    The coupling between the ion cyclotron (IC) antenna and the ITER plasma (as expressed by the load resistance the antenna sees) will experience relatively fast variations due to plasma edge profile modifications. If uncompensated, these will cause an increase in the amount of power reflected back to the transmitter and ultimately a decrease in the amount of radio frequency (rf) power to the plasma caused by protective suppression of the amount of rf power generated by the transmitter. The goals of this task were to study several alternate designs for a tuning and matching (T ampersand M) system and to recommend some research and development (R ampersand D) tasks that could be carried out to test some of the most promising concepts. Analyses of five different T ampersand M configurations are presented in this report. They each have different advantages and disadvantages, and the choice among them must be made depending on the requirements for the IC system. Several general conclusions emerge from our study: The use of a hybrid splitter as a passive reflected-power dump [''edge localized mode (ELM)-dump''] appears very promising; this configuration will protect the rf power sources from reflected power during changes in plasma loading due to plasma motion or profile changes (e.g., ELM- induced changes in the plasma scrape-off region) and requires no active control of the rf system. Trade-offs between simplicity of design and capability of the system must be made. Simple system designs with few components near the antenna either have high voltages over considerable distances of transmission lines, or they are not easily tuned to operate at different frequencies. Designs using frequency shifts and/or fast tuning elements can provide fast matching over a wide range of plasma loading; however, the designs studied here require components near the antenna, complicating assembly and maintenance. Capacitor-tuned resonant systems may offer a good compromise

  8. Design of fast tuning elements for the ITER ICH system

    Energy Technology Data Exchange (ETDEWEB)

    Swain, D.W.; Goulding, R.H.

    1996-05-01

    The coupling between the ion cyclotron (IC) antenna and the ITER plasma (as expressed by the load resistance the antenna sees) will experience relatively fast variations due to plasma edge profile modifications. If uncompensated, these will cause an increase in the amount of power reflected back to the transmitter and ultimately a decrease in the amount of radio frequency (rf) power to the plasma caused by protective suppression of the amount of rf power generated by the transmitter. The goals of this task were to study several alternate designs for a tuning and matching (T&M) system and to recommend some research and development (R&D) tasks that could be carried out to test some of the most promising concepts. Analyses of five different T&M configurations are presented in this report. They each have different advantages and disadvantages, and the choice among them must be made depending on the requirements for the IC system. Several general conclusions emerge from our study: The use of a hybrid splitter as a passive reflected-power dump [``edge localized mode (ELM)-dump``] appears very promising; this configuration will protect the rf power sources from reflected power during changes in plasma loading due to plasma motion or profile changes (e.g., ELM- induced changes in the plasma scrape-off region) and requires no active control of the rf system. Trade-offs between simplicity of design and capability of the system must be made. Simple system designs with few components near the antenna either have high voltages over considerable distances of transmission lines, or they are not easily tuned to operate at different frequencies. Designs using frequency shifts and/or fast tuning elements can provide fast matching over a wide range of plasma loading; however, the designs studied here require components near the antenna, complicating assembly and maintenance. Capacitor-tuned resonant systems may offer a good compromise.

  9. High precision tune and coupling measurements and tune/coupling feedback in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Minty, M.; Curcio, A.; Dawson, C.; Degen, C.; Luo, Y.; Marr, G.; Martin, B.; Marusic, A.; Mernick, K.; Oddo, P.; Russo, T.; Schoefer, V.; Schroeder, R.; Schulthiess, C.; Wilinski, M.

    2010-08-01

    Precision measurement and control of the betatron tunes and betatron coupling in RHIC are required for establishing and maintaining both good operating conditions and, particularly during the ramp to high beam energies, high proton beam polarization. While the proof-of-principle for simultaneous tune and coupling feedback was successfully demonstrated earlier, routine application of these systems has only become possible recently. Following numerous modifications for improved measurement resolution and feedback control, the time required to establish full-energy beams with the betatron tunes and coupling regulated by feedback was reduced from several weeks to a few hours. A summary of these improvements, select measurements benefitting from the improved resolution and a review of system performance are the subject of this report.

  10. Tuning positive feedback for signal detection in noisy dynamic environments.

    Science.gov (United States)

    Johansson, Anders; Ramsch, Kai; Middendorf, Martin; Sumpter, David J T

    2012-09-21

    Learning from previous actions is a key feature of decision-making. Diverse biological systems, from neuronal assemblies to insect societies, use a combination of positive feedback and forgetting of stored memories to process and respond to input signals. Here we look how these systems deal with a dynamic two-armed bandit problem of detecting a very weak signal in the presence of a high degree of noise. We show that by tuning the form of positive feedback and the decay rate to appropriate values, a single tracking variable can effectively detect dynamic inputs even in the presence of a large degree of noise. In particular, we show that when tuned appropriately a simple positive feedback algorithm is Fisher efficient, in that it can track changes in a signal on a time of order L(h)=(|h|/σ)(-2), where |h| is the magnitude of the signal and σ the magnitude of the noise. Copyright © 2012. Published by Elsevier Ltd.

  11. Intelligent tuning method of PID parameters based on iterative learning control for atomic force microscopy.

    Science.gov (United States)

    Liu, Hui; Li, Yingzi; Zhang, Yingxu; Chen, Yifu; Song, Zihang; Wang, Zhenyu; Zhang, Suoxin; Qian, Jianqiang

    2018-01-01

    Proportional-integral-derivative (PID) parameters play a vital role in the imaging process of an atomic force microscope (AFM). Traditional parameter tuning methods require a lot of manpower and it is difficult to set PID parameters in unattended working environments. In this manuscript, an intelligent tuning method of PID parameters based on iterative learning control is proposed to self-adjust PID parameters of the AFM according to the sample topography. This method gets enough information about the output signals of PID controller and tracking error, which will be used to calculate the proper PID parameters, by repeated line scanning until convergence before normal scanning to learn the topography. Subsequently, the appropriate PID parameters are obtained by fitting method and then applied to the normal scanning process. The feasibility of the method is demonstrated by the convergence analysis. Simulations and experimental results indicate that the proposed method can intelligently tune PID parameters of the AFM for imaging different topographies and thus achieve good tracking performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Iterative learning control with sampled-data feedback for robot manipulators

    Directory of Open Access Journals (Sweden)

    Delchev Kamen

    2014-09-01

    Full Text Available This paper deals with the improvement of the stability of sampled-data (SD feedback control for nonlinear multiple-input multiple-output time varying systems, such as robotic manipulators, by incorporating an off-line model based nonlinear iterative learning controller. The proposed scheme of nonlinear iterative learning control (NILC with SD feedback is applicable to a large class of robots because the sampled-data feedback is required for model based feedback controllers, especially for robotic manipulators with complicated dynamics (6 or 7 DOF, or more, while the feedforward control from the off-line iterative learning controller should be assumed as a continuous one. The robustness and convergence of the proposed NILC law with SD feedback is proven, and the derived sufficient condition for convergence is the same as the condition for a NILC with a continuous feedback control input. With respect to the presented NILC algorithm applied to a virtual PUMA 560 robot, simulation results are presented in order to verify convergence and applicability of the proposed learning controller with SD feedback controller attached

  13. Non-parametric Tuning of PID Controllers A Modified Relay-Feedback-Test Approach

    CERN Document Server

    Boiko, Igor

    2013-01-01

    The relay feedback test (RFT) has become a popular and efficient  tool used in process identification and automatic controller tuning. Non-parametric Tuning of PID Controllers couples new modifications of classical RFT with application-specific optimal tuning rules to form a non-parametric method of test-and-tuning. Test and tuning are coordinated through a set of common parameters so that a PID controller can obtain the desired gain or phase margins in a system exactly, even with unknown process dynamics. The concept of process-specific optimal tuning rules in the nonparametric setup, with corresponding tuning rules for flow, level pressure, and temperature control loops is presented in the text.   Common problems of tuning accuracy based on parametric and non-parametric approaches are addressed. In addition, the text treats the parametric approach to tuning based on the modified RFT approach and the exact model of oscillations in the system under test using the locus of a perturbedrelay system (LPRS) meth...

  14. Two-Directional Tuning of Distributed Feedback Film Dye Laser Devices

    Directory of Open Access Journals (Sweden)

    Hongtao Feng

    2017-12-01

    Full Text Available We demonstrate a two-directional tuning method of distributed feedback (DFB film dye laser devices to achieve high quality lasing and a large tuning range. In this work, we proposed a simple method to fabricate a continuous tunable solid-state dye laser on a flexible Polydimethylsiloxane (PDMS film. In order to obtain stable and tunable output lasing, the stretching property of the gelatine host was improved by mixing with a certain ratio of glycerol to prevent DFB cavity destruction. We employed two different tuning strategies of the DFB film dye lasers, by stretching the PDMS film in two perpendicular directions, and a nearly 40 nm tuning range in each direction was achieved. The laser device maintained single mode lasing with 0.12 nm linewidth during the tuning process. The reported tunable DFB film dye laser devices have huge potential as coherent light sources for sensing and spectroscopy applications.

  15. A Real-Time Optimization Framework for the Iterative Controller Tuning Problem

    Directory of Open Access Journals (Sweden)

    Gene A. Bunin

    2013-09-01

    Full Text Available We investigate the general iterative controller tuning (ICT problem, where the task is to find a set of controller parameters that optimize some user-defined performance metric when the same control task is to be carried out repeatedly. Following a repeatability assumption on the system, we show that the ICT problem may be formulated as a real-time optimization (RTO problem, thus allowing for the ICT problem to be solved in the RTO framework, which is both very flexible and comes with strong theoretical guarantees. In particular, we propose the use of a recently released RTO solver and outline a simple procedure for how this solver may be configured to solve ICT problems. The effectiveness of the proposed method is illustrated by successfully applying it to four case studies—two experimental and two simulated—that cover the tuning of model-predictive, general fixed-order and PID controllers, as well as a system of controllers working in parallel.

  16. A novel chaotic block cryptosystem based on iterating map with output-feedback

    International Nuclear Information System (INIS)

    Yang Degang; Liao Xiaofeng; Wang Yong; Yang Huaqian; Wei Pengcheng

    2009-01-01

    A novel method for encryption based on iterating map with output-feedback is presented in this paper. The output-feedback, instead of simply mixing the chaotic signal of the proposed chaotic cryptosystem with the cipher-text, is relating to previous cipher-text that is obtained through the plaintext and key. Some simulated experiments are performed to substantiate that our method can make cipher-text more confusion and diffusion and that the proposed method is practical whenever efficiency, cipher-text length or security is concerned.

  17. Enhancing imaging contrast via weighted feedback for iterative multi-image phase retrieval

    Science.gov (United States)

    Guo, Cheng; Li, Qiang; Zhang, Xiaoqing; Tan, Jiubin; Liu, Shutian; Liu, Zhengjun

    2018-01-01

    Iterative phase retrieval (IPR) has developed into a feasible and simple computational method to retrieve a complex-valued sample. Due to coherent illumination, the reconstructed image quality is degraded by speckle noise arising from a laser. Accordingly, partially coherent illumination has been introduced to alleviate this restriction. We apply weighted feedback modality into multidistance and multiwavelength phase retrieval to realize high-contrast and fast imaging. In simulation, it is proved that IPR based on weighted feedback accelerates the convergence in partially coherent illumination and speckle illumination. In experiment, the resolution chart and biological specimen are reconstructed in lensless and lens-based systems, which also demonstrate the performance of weighted feedback. This work provides a simple and high-contrast imaging modality for IPR. Also, it facilitates compact and flexible experimental implementation for label-free imaging.

  18. Data Driven Tuning of Inventory Controllers

    DEFF Research Database (Denmark)

    Huusom, Jakob Kjøbsted; Santacoloma, Paloma Andrade; Poulsen, Niels Kjølstad

    2007-01-01

    A systematic method for criterion based tuning of inventory controllers based on data-driven iterative feedback tuning is presented. This tuning method circumvent problems with modeling bias. The process model used for the design of the inventory control is utilized in the tuning...... as an approximation to reduce time required on experiments. The method is illustrated in an application with a multivariable inventory control implementation on a four tank system....

  19. Low-Bit Rate Feedback Strategies for Iterative IA-Precoded MIMO-OFDM-Based Systems

    Science.gov (United States)

    Teodoro, Sara; Silva, Adão; Dinis, Rui; Gameiro, Atílio

    2014-01-01

    Interference alignment (IA) is a promising technique that allows high-capacity gains in interference channels, but which requires the knowledge of the channel state information (CSI) for all the system links. We design low-complexity and low-bit rate feedback strategies where a quantized version of some CSI parameters is fed back from the user terminal (UT) to the base station (BS), which shares it with the other BSs through a limited-capacity backhaul network. This information is then used by BSs to perform the overall IA design. With the proposed strategies, we only need to send part of the CSI information, and this can even be sent only once for a set of data blocks transmitted over time-varying channels. These strategies are applied to iterative MMSE-based IA techniques for the downlink of broadband wireless OFDM systems with limited feedback. A new robust iterative IA technique, where channel quantization errors are taken into account in IA design, is also proposed and evaluated. With our proposed strategies, we need a small number of quantization bits to transmit and share the CSI, when comparing with the techniques used in previous works, while allowing performance close to the one obtained with perfect channel knowledge. PMID:24678274

  20. Low-Bit Rate Feedback Strategies for Iterative IA-Precoded MIMO-OFDM-Based Systems

    Directory of Open Access Journals (Sweden)

    Sara Teodoro

    2014-01-01

    Full Text Available Interference alignment (IA is a promising technique that allows high-capacity gains in interference channels, but which requires the knowledge of the channel state information (CSI for all the system links. We design low-complexity and low-bit rate feedback strategies where a quantized version of some CSI parameters is fed back from the user terminal (UT to the base station (BS, which shares it with the other BSs through a limited-capacity backhaul network. This information is then used by BSs to perform the overall IA design. With the proposed strategies, we only need to send part of the CSI information, and this can even be sent only once for a set of data blocks transmitted over time-varying channels. These strategies are applied to iterative MMSE-based IA techniques for the downlink of broadband wireless OFDM systems with limited feedback. A new robust iterative IA technique, where channel quantization errors are taken into account in IA design, is also proposed and evaluated. With our proposed strategies, we need a small number of quantization bits to transmit and share the CSI, when comparing with the techniques used in previous works, while allowing performance close to the one obtained with perfect channel knowledge.

  1. The Research of Multiple Attenuation Based on Feedback Iteration and Independent Component Analysis

    Science.gov (United States)

    Xu, X.; Tong, S.; Wang, L.

    2017-12-01

    How to solve the problem of multiple suppression is a difficult problem in seismic data processing. The traditional technology for multiple attenuation is based on the principle of the minimum output energy of the seismic signal, this criterion is based on the second order statistics, and it can't achieve the multiple attenuation when the primaries and multiples are non-orthogonal. In order to solve the above problems, we combine the feedback iteration method based on the wave equation and the improved independent component analysis (ICA) based on high order statistics to suppress the multiple waves. We first use iterative feedback method to predict the free surface multiples of each order. Then, in order to predict multiples from real multiple in amplitude and phase, we design an expanded pseudo multi-channel matching filtering method to get a more accurate matching multiple result. Finally, we present the improved fast ICA algorithm which is based on the maximum non-Gauss criterion of output signal to the matching multiples and get better separation results of the primaries and the multiples. The advantage of our method is that we don't need any priori information to the prediction of the multiples, and can have a better separation result. The method has been applied to several synthetic data generated by finite-difference model technique and the Sigsbee2B model multiple data, the primaries and multiples are non-orthogonal in these models. The experiments show that after three to four iterations, we can get the perfect multiple results. Using our matching method and Fast ICA adaptive multiple subtraction, we can not only effectively preserve the effective wave energy in seismic records, but also can effectively suppress the free surface multiples, especially the multiples related to the middle and deep areas.

  2. Iter

    Science.gov (United States)

    Iotti, Robert

    2015-04-01

    ITER is an international experimental facility being built by seven Parties to demonstrate the long term potential of fusion energy. The ITER Joint Implementation Agreement (JIA) defines the structure and governance model of such cooperation. There are a number of necessary conditions for such international projects to be successful: a complete design, strong systems engineering working with an agreed set of requirements, an experienced organization with systems and plans in place to manage the project, a cost estimate backed by industry, and someone in charge. Unfortunately for ITER many of these conditions were not present. The paper discusses the priorities in the JIA which led to setting up the project with a Central Integrating Organization (IO) in Cadarache, France as the ITER HQ, and seven Domestic Agencies (DAs) located in the countries of the Parties, responsible for delivering 90%+ of the project hardware as Contributions-in-Kind and also financial contributions to the IO, as ``Contributions-in-Cash.'' Theoretically the Director General (DG) is responsible for everything. In practice the DG does not have the power to control the work of the DAs, and there is not an effective management structure enabling the IO and the DAs to arbitrate disputes, so the project is not really managed, but is a loose collaboration of competing interests. Any DA can effectively block a decision reached by the DG. Inefficiencies in completing design while setting up a competent organization from scratch contributed to the delays and cost increases during the initial few years. So did the fact that the original estimate was not developed from industry input. Unforeseen inflation and market demand on certain commodities/materials further exacerbated the cost increases. Since then, improvements are debatable. Does this mean that the governance model of ITER is a wrong model for international scientific cooperation? I do not believe so. Had the necessary conditions for success

  3. Implementation on a mock-up of the automatic feedback controlled matching options of the full ITER ICRH system

    International Nuclear Information System (INIS)

    Grine, D.; Vervier, M.; Messiaen, A.; Dumortier, P.

    2011-01-01

    The hybrid option has been chosen for the matching of the ITER ICRH system. Presently, the corresponding 3 dB hybrid matching circuit is being developed, and tested for optimization on a low-powered scaled mock-up. Impedance matching and antenna array current control of the hybrid option is provided by simultaneous feedback control of the decouplers and double stub tuners (23 actuators in total) and is being progressively implemented. Already half of the array has been successfully tested. The article goes into the details of the automatic feedback implementation and covers the developed control systems and algorithms. Feedback stability and starting conditions are also discussed.

  4. Attention to Color Sharpens Neural Population Tuning via Feedback Processing in the Human Visual Cortex Hierarchy.

    Science.gov (United States)

    Bartsch, Mandy V; Loewe, Kristian; Merkel, Christian; Heinze, Hans-Jochen; Schoenfeld, Mircea A; Tsotsos, John K; Hopf, Jens-Max

    2017-10-25

    Attention can facilitate the selection of elementary object features such as color, orientation, or motion. This is referred to as feature-based attention and it is commonly attributed to a modulation of the gain and tuning of feature-selective units in visual cortex. Although gain mechanisms are well characterized, little is known about the cortical processes underlying the sharpening of feature selectivity. Here, we show with high-resolution magnetoencephalography in human observers (men and women) that sharpened selectivity for a particular color arises from feedback processing in the human visual cortex hierarchy. To assess color selectivity, we analyze the response to a color probe that varies in color distance from an attended color target. We find that attention causes an initial gain enhancement in anterior ventral extrastriate cortex that is coarsely selective for the target color and transitions within ∼100 ms into a sharper tuned profile in more posterior ventral occipital cortex. We conclude that attention sharpens selectivity over time by attenuating the response at lower levels of the cortical hierarchy to color values neighboring the target in color space. These observations support computational models proposing that attention tunes feature selectivity in visual cortex through backward-propagating attenuation of units less tuned to the target. SIGNIFICANCE STATEMENT Whether searching for your car, a particular item of clothing, or just obeying traffic lights, in everyday life, we must select items based on color. But how does attention allow us to select a specific color? Here, we use high spatiotemporal resolution neuromagnetic recordings to examine how color selectivity emerges in the human brain. We find that color selectivity evolves as a coarse to fine process from higher to lower levels within the visual cortex hierarchy. Our observations support computational models proposing that feature selectivity increases over time by attenuating the

  5. Dynamic Output Feedback Power-Level Control for the MHTGR Based On Iterative Damping Assignment

    Directory of Open Access Journals (Sweden)

    Zhe Dong

    2012-06-01

    Full Text Available Because of its strong inherent safety features and high outlet temperature, the modular high temperature gas-cooled nuclear reactor (MHTGR is already seen as the central part of the next generation of nuclear plants. Such power plants are being considered for industrial applications with a wide range of power levels, and thus power-level control is an important technique for their efficient and stable operation. Stimulated by the high regulation performance provided by nonlinear controllers, a novel dynamic output-feedback nonlinear power-level regulator is developed in this paper based on the technique of iterative damping assignment (IDA. This control strategy can provide the L2 disturbance attenuation performance under modeling uncertainty or exterior disturbance, and can also guarantee the globally asymptotic closed-loop stability without uncertainty and disturbance. This newly built control strategy is then applied to the power-level regulation of the HTR-PM plant, and numerical simulation results show both the feasibility and high performance of this newly-built control strategy. Furthermore, the relationship between the values of the parameters and the performance of this controller is not only illustrated numerically but also analyzed theoretically.

  6. Tuning iteration space slicing based tiled multi-core code implementing Nussinov's RNA folding.

    Science.gov (United States)

    Palkowski, Marek; Bielecki, Wlodzimierz

    2018-01-15

    RNA folding is an ongoing compute-intensive task of bioinformatics. Parallelization and improving code locality for this kind of algorithms is one of the most relevant areas in computational biology. Fortunately, RNA secondary structure approaches, such as Nussinov's recurrence, involve mathematical operations over affine control loops whose iteration space can be represented by the polyhedral model. This allows us to apply powerful polyhedral compilation techniques based on the transitive closure of dependence graphs to generate parallel tiled code implementing Nussinov's RNA folding. Such techniques are within the iteration space slicing framework - the transitive dependences are applied to the statement instances of interest to produce valid tiles. The main problem at generating parallel tiled code is defining a proper tile size and tile dimension which impact parallelism degree and code locality. To choose the best tile size and tile dimension, we first construct parallel parametric tiled code (parameters are variables defining tile size). With this purpose, we first generate two nonparametric tiled codes with different fixed tile sizes but with the same code structure and then derive a general affine model, which describes all integer factors available in expressions of those codes. Using this model and known integer factors present in the mentioned expressions (they define the left-hand side of the model), we find unknown integers in this model for each integer factor available in the same fixed tiled code position and replace in this code expressions, including integer factors, with those including parameters. Then we use this parallel parametric tiled code to implement the well-known tile size selection (TSS) technique, which allows us to discover in a given search space the best tile size and tile dimension maximizing target code performance. For a given search space, the presented approach allows us to choose the best tile size and tile dimension in

  7. Influence of visual feedback on human task performance in ITER remote handling

    NARCIS (Netherlands)

    Schropp, Gwendolijn Y R; Heemskerk, Cock J M; Kappers, Astrid M L; Bergmann Tiest, Wouter M; Elzendoorn, Ben S Q; Bult, David

    In ITER, maintenance operations will be largely performed by remote handling (RH). Before ITER can be put into operation, safety regulations and licensing authorities require proof of maintainability for critical components. Part of the proof will come from using standard components and procedures.

  8. A Data-Driven Control Design Approach for Freeway Traffic Ramp Metering with Virtual Reference Feedback Tuning

    Directory of Open Access Journals (Sweden)

    Shangtai Jin

    2014-01-01

    Full Text Available ALINEA is a simple, efficient, and easily implemented ramp metering strategy. Virtual reference feedback tuning (VRFT is most suitable for many practical systems since it is a “one-shot” data-driven control design methodology. This paper presents an application of VRFT to a ramp metering problem of freeway traffic system. When there is not enough prior knowledge of the controlled system to select a proper parameter of ALINEA, the VRFT approach is used to optimize the ALINEA's parameter by only using a batch of input and output data collected from the freeway traffic system. The extensive simulations are built on both the macroscopic MATLAB platform and the microscopic PARAMICS platform to show the effectiveness and applicability of the proposed data-driven controller tuning approach.

  9. Adaptive Iterative Soft-Input Soft-Output Parallel Decision-Feedback Detectors for Asynchronous Coded DS-CDMA Systems

    Directory of Open Access Journals (Sweden)

    Zhang Wei

    2005-01-01

    Full Text Available The optimum and many suboptimum iterative soft-input soft-output (SISO multiuser detectors require a priori information about the multiuser system, such as the users' transmitted signature waveforms, relative delays, as well as the channel impulse response. In this paper, we employ adaptive algorithms in the SISO multiuser detector in order to avoid the need for this a priori information. First, we derive the optimum SISO parallel decision-feedback detector for asynchronous coded DS-CDMA systems. Then, we propose two adaptive versions of this SISO detector, which are based on the normalized least mean square (NLMS and recursive least squares (RLS algorithms. Our SISO adaptive detectors effectively exploit the a priori information of coded symbols, whose soft inputs are obtained from a bank of single-user decoders. Furthermore, we consider how to select practical finite feedforward and feedback filter lengths to obtain a good tradeoff between the performance and computational complexity of the receiver.

  10. INTELLIGENT FRACTIONAL ORDER ITERATIVE LEARNING CONTROL USING FEEDBACK LINEARIZATION FOR A SINGLE-LINK ROBOT

    Directory of Open Access Journals (Sweden)

    Iman Ghasemi

    2017-05-01

    Full Text Available In this paper, iterative learning control (ILC is combined with an optimal fractional order derivative (BBO-Da-type ILC and optimal fractional and proportional-derivative (BBO-PDa-type ILC. In the update law of Arimoto's derivative iterative learning control, a first order derivative of tracking error signal is used. In the proposed method, fractional order derivative of the error signal is stated in term of 'sa' where  to update iterative learning control law. Two types of fractional order iterative learning control namely PDa-type ILC and Da-type ILC are gained for different value of a. In order to improve the performance of closed-loop control system, coefficients of both  and  learning law i.e. proportional , derivative  and  are optimized using Biogeography-Based optimization algorithm (BBO. Outcome of the simulation results are compared with those of the conventional fractional order iterative learning control to verify effectiveness of BBO-Da-type ILC and BBO-PDa-type ILC

  11. Modified Newton-Raphson method to tune feedback gains of control system for standing by functional neuromuscular stimulation following spinal cord injury.

    Science.gov (United States)

    Nataraj, Raviraj; Audu, Musa L; Triolo, Ronald J

    2014-11-01

    Functional neuromuscular stimulation (FNS) can restore standing capabilities following spinal cord injury. Feedback control of these systems can optimize performance by reducing the required upper extremity support. However, tuning these control systems can be intensive and clinically inconvenient. This case study investigated a clinical method to efficiently tune feedback gains for a control system utilizing feedback of total body center of mass acceleration to modulate stimulation levels to targeted paralyzed musculature of the lower extremities and trunk. Gains for this control system were tuned to minimize the stabilization loading by one arm against internal postural perturbations volitionally-generated during manipulation of an object using the other arm. An algorithm based on a modified form of the Newton-Raphson method was employed to find the optimal feedback gains with lower subject effort than that to determine the original tuning curves. This method accurately (<6.2% error) approximated the optimal gains with 70% fewer manipulations by the subject. These results suggest that optimal feedback gains for the specific FNS control system can be determined systematically with considerably less effort than heuristic gain tuning. This demonstrates the potential for devising simple, convenient methods for effective system re-tuning during clinical usage.

  12. Frequency-feedback tuning for single-cell cavity under rf heating

    International Nuclear Information System (INIS)

    Stepp, J.D.; Bridges, J.F.

    1993-01-01

    A tuning system is described that is being used to match the source frequency of a high-power klystron on the resonant frequency of the prototype single-cell cavity for the 7-GeV Advance Photon Source (APS) storage ring. Typically a water-cooled piston tuner is required to adjust the reactive component of the cavity's impedance to minimize reflected power back to the RF drive source. As the cavity watts expand due to RF heating, the resonant frequency decreases. Adjusting the source frequency to follow the cavity resonant frequency is a convenient method used to condition the cavity (for vacuum) at high power levels, in this case, 1 MV gap voltage at 100 kW power level. The tuning system consists of two coupling ports, a phase detector, a digitizing I/O system, and a DC coupled FM-modulated RF source. Proportional Integral Derivative (PID) loop parameters for the Experimental Physics and Industrial Control System (EPICS) software are calculated, and data is presented showing the damped response to peturbations on the loop. The timing system presented here does not need water-cooling, has no moving parts to wear out, and has an inherently faster response time. Its one limitation is the digitizing sampling rate. The only limitation in tuning range is the bandwidth of the RF source

  13. Iterative feedback bio-printing-derived cell-laden hydrogel scaffolds with optimal geometrical fidelity and cellular controllability.

    Science.gov (United States)

    Wang, Ling; Xu, Ming-En; Luo, Li; Zhou, Yongyong; Si, Peijian

    2018-02-12

    For three-dimensional bio-printed cell-laden hydrogel tissue constructs, the well-designed internal porous geometry is tailored to obtain the desired structural and cellular properties. However, significant differences often exist between the designed and as-printed scaffolds because of the inherent characteristics of hydrogels and cells. In this study, an iterative feedback bio-printing (IFBP) approach based on optical coherence tomography (OCT) for the fabrication of cell-laden hydrogel scaffolds with optimal geometrical fidelity and cellular controllability was proposed. A custom-made swept-source OCT (SS-OCT) system was applied to characterize the printed scaffolds quantitatively. Based on the obtained empirical linear formula from the first experimental feedback loop, we defined the most appropriate design constraints and optimized the printing process to improve the geometrical fidelity. The effectiveness of IFBP was verified from the second run using gelatin/alginate hydrogel scaffolds laden with C3A cells. The mismatch of the morphological parameters greatly decreased from 40% to within 7%, which significantly optimized the cell viability, proliferation, and morphology, as well as the representative expression of hepatocyte markers, including CYP3A4 and albumin, of the printed cell-laden hydrogel scaffolds. The demonstrated protocol paves the way for the mass fabrication of cell-laden hydrogel scaffolds, engineered tissues, and scaled-up applications of the 3D bio-printing technique.

  14. Evaluation of physicians' professional performance: An iterative development and validation study of multisource feedback instruments

    Directory of Open Access Journals (Sweden)

    Overeem Karlijn

    2012-03-01

    Full Text Available Abstract Background There is a global need to assess physicians' professional performance in actual clinical practice. Valid and reliable instruments are necessary to support these efforts. This study focuses on the reliability and validity, the influences of some sociodemographic biasing factors, associations between self and other evaluations, and the number of evaluations needed for reliable assessment of a physician based on the three instruments used for the multisource assessment of physicians' professional performance in the Netherlands. Methods This observational validation study of three instruments underlying multisource feedback (MSF was set in 26 non-academic hospitals in the Netherlands. In total, 146 hospital-based physicians took part in the study. Each physician's professional performance was assessed by peers (physician colleagues, co-workers (including nurses, secretary assistants and other healthcare professionals and patients. Physicians also completed a self-evaluation. Ratings of 864 peers, 894 co-workers and 1960 patients on MSF were available. We used principal components analysis and methods of classical test theory to evaluate the factor structure, reliability and validity of instruments. We used Pearson's correlation coefficient and linear mixed models to address other objectives. Results The peer, co-worker and patient instruments respectively had six factors, three factors and one factor with high internal consistencies (Cronbach's alpha 0.95 - 0.96. It appeared that only 2 percent of variance in the mean ratings could be attributed to biasing factors. Self-ratings were not correlated with peer, co-worker or patient ratings. However, ratings of peers, co-workers and patients were correlated. Five peer evaluations, five co-worker evaluations and 11 patient evaluations are required to achieve reliable results (reliability coefficient ≥ 0.70. Conclusions The study demonstrated that the three MSF instruments produced

  15. Self-tuning pressure-feedback control by pole placement for vibration reduction of excavator with independent metering fluid power system

    Science.gov (United States)

    Ding, Ruqi; Xu, Bing; Zhang, Junhui; Cheng, Min

    2017-08-01

    Independent metering control systems are promising fluid power technologies compared with traditional valve controlled systems. By breaking the mechanical coupling between the inlet and outlet, the meter-out valve can open as large as possible to reduce energy consumptions. However, the lack of damping in outlet causes stronger vibrations. To address the problem, the paper designs a hybrid control method combining dynamic pressure-feedback and active damping control. The innovation resides in the optimization of damping by introducing pressure feedback to make trade-offs between high stability and fast response. To achieve this goal, the dynamic response pertaining to the control parameters consisting of feedback gain and cut-off frequency, are analyzed via pole-zero locations. Accordingly, these parameters are tuned online in terms of guaranteed dominant pole placement such that the optimal damping can be accurately captured under a considerable variation of operating conditions. The experiment is deployed in a mini-excavator. The results pertaining to different control parameters confirm the theoretical expectations via pole-zero locations. By using proposed self-tuning controller, the vibrations are almost eliminated after only one overshoot for different operation conditions. The overshoots are also reduced with less decrease of the response time. In addition, the energy-saving capability of independent metering system is still not affected by the improvement of controllability.

  16. Controller design for the improvement of feedback properties: A method for tuning the weight in the evaluation function of the LQG theory

    Science.gov (United States)

    Saeki, Masami; Li, Hui-Zhong; Ando, Kazuaki

    1987-01-01

    In the controller design of a linear time-invariant system, it is important to improve the feedback properties such as robust stability and sensitivity. In the multi-input multi-output case, these properties can be estimated by using the singular values of return difference matrix. The design method to obtain better singular-value-points is desired. How to tune the weight matrix of performance index and/or covariance matrix of noise in the Linear Quadratic Gaussian (LQC) theory to get a desired singular-value-plot was studied. First, the property of singular-value plots of return difference matrix of a system designed by LQG theory is examined from the viewpoint of tuning weight. Second, a distance between real singular-value-plots and a desired plot is defined, and the weight of performance index is numerically determined by quasi-Newton method so that the distance is minimized.

  17. Real-time control of divertor detachment in H-mode with impurity seeding using Langmuir probe feedback in JET-ITER-like wall

    Science.gov (United States)

    Guillemaut, C.; Lennholm, M.; Harrison, J.; Carvalho, I.; Valcarcel, D.; Felton, R.; Griph, S.; Hogben, C.; Lucock, R.; Matthews, G. F.; Perez Von Thun, C.; Pitts, R. A.; Wiesen, S.; contributors, JET

    2017-04-01

    Burning plasmas with 500 MW of fusion power on ITER will rely on partially detached divertor operation to keep target heat loads at manageable levels. Such divertor regimes will be maintained by a real-time control system using the seeding of radiative impurities like nitrogen (N), neon or argon as actuator and one or more diagnostic signals as sensors. Recently, real-time control of divertor detachment has been successfully achieved in Type I ELMy H-mode JET-ITER-like wall discharges by using saturation current (I sat) measurements from divertor Langmuir probes as feedback signals to control the level of N seeding. The degree of divertor detachment is calculated in real-time by comparing the outer target peak I sat measurements to the peak I sat value at the roll-over in order to control the opening of the N injection valve. Real-time control of detachment has been achieved in both fixed and swept strike point experiments. The system has been progressively improved and can now automatically drive the divertor conditions from attached through high recycling and roll-over down to a user-defined level of detachment. Such a demonstration is a successful proof of principle in the context of future operation on ITER which will be extensively equipped with divertor target probes.

  18. A rigorous model of reflex function indicates that position and force feedback are flexibly tuned to position and force tasks

    NARCIS (Netherlands)

    Mugge, W.; Abbink, D.A.; Schouten, A.C.; Dewald, J.P.A.; Van der Helm, F.C.T.

    2009-01-01

    This study aims to quantify the separate contributions of muscle force feedback, muscle spindle activity and co-contraction to the performance of voluntary tasks (‘‘reduce the influence of perturbations on maintained force or position’’). Most human motion control studies either isolate only one

  19. Development of a Newtron-Krylov Iterative Method to Address Strong Non-Linear Feedback Effect in BWR Core Simulators

    International Nuclear Information System (INIS)

    Doddy Kastanya; Paul Turinsky

    2002-01-01

    A Newton-BICGSTAB solver has been developed to reduce the CPU execution time of BWR core simulators. The new solver treats the strong non-linearities in the problem explicitly using the Newton's method, replacing the traditionally used nested iterative approach. The Newton's method provides the solver with a higher-than-linear convergence rate, assuming that a good initial estimate of the unknowns is provided. Within each Newton iteration, an appropriately preconditioned BICGSTAB method is utilized for solving the linearized system of equations. Taking advantage of the higher convergence rate provided by the Newton's method and utilizing an efficient preconditioned BICGSTAB solver, we have developed a computationally efficient Newton-BICGSTAB solver to evaluate the three-dimensional, two-group neutron diffusion equations coupled with a two-phase flow model within a BWR core simulator. The robustness of the solver has been tested against numerous BWR core configurations and consistent results have been observed each time. The Newton-BICGSTAB solver provides an overall speedup of around 1.7 to the core simulator, with reference to the traditional approach. Isolating the solver portion of the core simulator, one can see that the new algorithm actually provides a speedup of around 1.9, of which 48% can be attributed to the BICGSTAB solver and the remaining 52% to Newton's method

  20. A satellite digital controller or 'play that PID tune again, Sam'. [Position, Integral, Derivative feedback control algorithm for design strategy

    Science.gov (United States)

    Seltzer, S. M.

    1976-01-01

    The problem discussed is to design a digital controller for a typical satellite. The controlled plant is considered to be a rigid body acting in a plane. The controller is assumed to be a digital computer which, when combined with the proposed control algorithm, can be represented as a sampled-data system. The objective is to present a design strategy and technique for selecting numerical values for the control gains (assuming position, integral, and derivative feedback) and the sample rate. The technique is based on the parameter plane method and requires that the system be amenable to z-transform analysis.

  1. ITER...ation

    International Nuclear Information System (INIS)

    Troyon, F.

    1997-01-01

    Recurrent attacks against ITER, the new generation of tokamak are a mix of political and scientific arguments. This short article draws a historical review of the European fusion program. This program has allowed to build and manage several installations in the aim of getting experimental results necessary to lead the program forwards. ITER will bring together a fusion reactor core with technologies such as materials, superconductive coils, heating devices and instrumentation in order to validate and delimit the operating range. ITER will be a logical and decisive step towards the use of controlled fusion. (A.C.)

  2. Density control in ITER: an iterative learning control and robust control approach

    Science.gov (United States)

    Ravensbergen, T.; de Vries, P. C.; Felici, F.; Blanken, T. C.; Nouailletas, R.; Zabeo, L.

    2018-01-01

    Plasma density control for next generation tokamaks, such as ITER, is challenging because of multiple reasons. The response of the usual gas valve actuators in future, larger fusion devices, might be too slow for feedback control. Both pellet fuelling and the use of feedforward-based control may help to solve this problem. Also, tight density limits arise during ramp-up, due to operational limits related to divertor detachment and radiative collapses. As the number of shots available for controller tuning will be limited in ITER, in this paper, iterative learning control (ILC) is proposed to determine optimal feedforward actuator inputs based on tracking errors, obtained in previous shots. This control method can take the actuator and density limits into account and can deal with large actuator delays. However, a purely feedforward-based density control may not be sufficient due to the presence of disturbances and shot-to-shot differences. Therefore, robust control synthesis is used to construct a robustly stabilizing feedback controller. In simulations, it is shown that this combined controller strategy is able to achieve good tracking performance in the presence of shot-to-shot differences, tight constraints, and model mismatches.

  3. Iterating skeletons

    DEFF Research Database (Denmark)

    Dieterle, Mischa; Horstmeyer, Thomas; Berthold, Jost

    2012-01-01

    a particular skeleton ad-hoc for repeated execution turns out to be considerably complicated, and raises general questions about introducing state into a stateless parallel computation. In addition, one would strongly prefer an approach which leaves the original skeleton intact, and only uses it as a building...... block inside a bigger structure. In this work, we present a general framework for skeleton iteration and discuss requirements and variations of iteration control and iteration body. Skeleton iteration is expressed by synchronising a parallel iteration body skeleton with a (likewise parallel) state......Skeleton-based programming is an area of increasing relevance with upcoming highly parallel hardware, since it substantially facilitates parallel programming and separates concerns. When parallel algorithms expressed by skeletons involve iterations – applying the same algorithm repeatedly...

  4. Research and Teaching: Using Models from the Literature and Iterative Feedback to Teach Students to Construct Effective Data Figures for Poster Presentations

    Science.gov (United States)

    Gray, Christine E.; Contreras-Shannon, Veronica E.

    2017-01-01

    Analyzing, interpreting, and clearly presenting real data are skills we hope to develop in all students, majors and nonmajors alike. These process skills require lots of practice coupled with targeted feedback from instructors or mentors. Here we present a pedagogy implemented within a course-based research experience that is designed to help…

  5. ITER safety

    International Nuclear Information System (INIS)

    Raeder, J.; Piet, S.; Buende, R.

    1991-01-01

    As part of the series of publications by the IAEA that summarize the results of the Conceptual Design Activities for the ITER project, this document describes the ITER safety analyses. It contains an assessment of normal operation effluents, accident scenarios, plasma chamber safety, tritium system safety, magnet system safety, external loss of coolant and coolant flow problems, and a waste management assessment, while it describes the implementation of the safety approach for ITER. The document ends with a list of major conclusions, a set of topical remarks on technical safety issues, and recommendations for the Engineering Design Activities, safety considerations for siting ITER, and recommendations with regard to the safety issues for the R and D for ITER. Refs, figs and tabs

  6. A State Feedback Controller Used to Solve an Ill-posed Linear System by a GL(n, R Iterative Algorithm

    Directory of Open Access Journals (Sweden)

    Chein-Shan Liu

    2013-11-01

    Full Text Available Starting from a quadratic invariant manifold in terms of the residual vector ${extbf r}={extbf B}{extbf x}-{extbf b}$ for an $n$-dimensional ill-posed linear algebraic equations system ${extbf B}{extbf x}={extbf b}$, we derive an ODEs system for ${extbf x}$ which is equipped with a state feedback controller to enforce the orbit of the state vector ${extbf x}$ on a specified manifold, whose residual-norm is exponentially decayed. To realize the above idea we develop a very powerful implicit scheme based on the novel $GL(n,{mathbb R}$ Lie-group method to integrate the resultant differential algebraic equation (DAE. Through numerical tests of inverse problems we find that the present Lie-group DAE algorithm can significantly accelerate the convergence speed, and is robust enough against the random noise.

  7. The development of a thermal hydraulic feedback mechanism with a quasi-fixed point iteration scheme for control rod position modeling for the TRIGSIMS-TH application

    Science.gov (United States)

    Karriem, Veronica V.

    Nuclear reactor design incorporates the study and application of nuclear physics, nuclear thermal hydraulic and nuclear safety. Theoretical models and numerical methods implemented in computer programs are utilized to analyze and design nuclear reactors. The focus of this PhD study's is the development of an advanced high-fidelity multi-physics code system to perform reactor core analysis for design and safety evaluations of research TRIGA-type reactors. The fuel management and design code system TRIGSIMS was further developed to fulfill the function of a reactor design and analysis code system for the Pennsylvania State Breazeale Reactor (PSBR). TRIGSIMS, which is currently in use at the PSBR, is a fuel management tool, which incorporates the depletion code ORIGEN-S (part of SCALE system) and the Monte Carlo neutronics solver MCNP. The diffusion theory code ADMARC-H is used within TRIGSIMS to accelerate the MCNP calculations. It manages the data and fuel isotopic content and stores it for future burnup calculations. The contribution of this work is the development of an improved version of TRIGSIMS, named TRIGSIMS-TH. TRIGSIMS-TH incorporates a thermal hydraulic module based on the advanced sub-channel code COBRA-TF (CTF). CTF provides the temperature feedback needed in the multi-physics calculations as well as the thermal hydraulics modeling capability of the reactor core. The temperature feedback model is using the CTF-provided local moderator and fuel temperatures for the cross-section modeling for ADMARC-H and MCNP calculations. To perform efficient critical control rod calculations, a methodology for applying a control rod position was implemented in TRIGSIMS-TH, making this code system a modeling and design tool for future core loadings. The new TRIGSIMS-TH is a computer program that interlinks various other functional reactor analysis tools. It consists of the MCNP5, ADMARC-H, ORIGEN-S, and CTF. CTF was coupled with both MCNP and ADMARC-H to provide the

  8. On equivalence classes in iterative learning control

    NARCIS (Netherlands)

    Verwoerd, M.H.A.; Meinsma, Gjerrit; de Vries, Theodorus J.A.

    2003-01-01

    This paper advocates a new approach to study the relation between causal iterative learning control (ILC) and conventional feedback control. Central to this approach is the introduction of the set of admissible pairs (of operators) defined with respect to a family of iterations. Considered are two

  9. Physics fundamentals for ITER

    International Nuclear Information System (INIS)

    Rosenbluth, M.N.

    1999-01-01

    The design of an experimental thermonuclear reactor requires both cutting-edge technology and physics predictions precise enough to carry forward the design. The past few years of worldwide physics studies have seen great progress in understanding, innovation and integration. We will discuss this progress and the remaining issues in several key physics areas. (1) Transport and plasma confinement. A worldwide database has led to an 'empirical scaling law' for tokamaks which predicts adequate confinement for the ITER fusion mission, albeit with considerable but acceptable uncertainty. The ongoing revolution in computer capabilities has given rise to new gyrofluid and gyrokinetic simulations of microphysics which may be expected in the near future to attain predictive accuracy. Important databases on H-mode characteristics and helium retention have also been assembled. (2) Divertors, heat removal and fuelling. A novel concept for heat removal - the radiative, baffled, partially detached divertor - has been designed for ITER. Extensive two-dimensional (2D) calculations have been performed and agree qualitatively with recent experiments. Preliminary studies of the interaction of this configuration with core confinement are encouraging and the success of inside pellet launch provides an attractive alternative fuelling method. (3) Macrostability. The ITER mission can be accomplished well within ideal magnetohydrodynamic (MHD) stability limits, except for internal kink modes. Comparisons with JET, as well as a theoretical model including kinetic effects, predict such sawteeth will be benign in ITER. Alternative scenarios involving delayed current penetration or off-axis current drive may be employed if required. The recent discovery of neoclassical beta limits well below ideal MHD limits poses a threat to performance. Extrapolation to reactor scale is as yet unclear. In theory such modes are controllable by current drive profile control or feedback and experiments should

  10. Embodied Tuning

    DEFF Research Database (Denmark)

    Mortensen, Christian Hviid; Vestergaard, Vitus

    2014-01-01

    and explore the physical gallery space. We implemented a simple low-cost prototype system called Exaudimus allowing users to search for the audio streams using their own bodies as a metaphorical radio tuning dial. We tested the concept in a public exhibition at the Media Museum in Denmark. A small qualitative...

  11. ITER magnets

    International Nuclear Information System (INIS)

    Bottura, L.; Hasegawa, M.; Heim, J.

    1991-01-01

    As part of the summary of the Conceptual Design Activities (CDA) for the International Thermonuclear Experimental Reactor (ITER), this document describes the magnet systems for ITER, including the Toroidal Field (TF) and Poloidal Field (PF) Magnets, the Structural Support System and Cryostat, the Cryogenic System, the TF and PF Power and Protection Systems, and Coil Services and Diagnostics. After an Introduction and Summary, the document discusses the (i) Design Basis, including General Requirements, Design Criteria, Design Philosophy, and the Database (a.o., engineering data on key materials and components), and (ii) the Subsystem Design and Analysis, including Conductor Design, TF Coil and Structure Design, TF Structural Analysis, PF Coil and Structure Design, PF Structural Performance, Fatigue Assessment of Structures, AC Loss Performance, Thermohydraulic Performance, Stability, Cryogenic System, Power Supply Systems, and Coil Services. All magnets are superconducting, (based on Nb 3 Sn) except the Active Control Coils inside the Vacuum Vessel. The fault analysis has been taken to a level consistent with the design definition, showing that the present design meets the requirement for passive safety or can be made to meet it with only minor modifications. A more detailed assessment in this regard is needed but must await further development of the design. In conclusion, the magnet design concepts presently proposed can be developed into an engineering design. Refs, figs and tabs

  12. The ITER project technological challenges

    CERN Multimedia

    CERN. Geneva; Lister, Joseph; Marquina, Miguel A; Todesco, Ezio

    2005-01-01

    The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the designer approach and the available technologies are critically discussed. The fourth lecture is devoted to the issue of performance prediction, from a superconducting wire to a large size conductor. The role of scaling laws, self-field, current distribution, voltage-current characteristic and transposition are...

  13. ITER council proceedings: 2001

    International Nuclear Information System (INIS)

    2001-01-01

    Continuing the ITER EDA, two further ITER Council Meetings were held since the publication of ITER EDA documentation series no, 20, namely the ITER Council Meeting on 27-28 February 2001 in Toronto, and the ITER Council Meeting on 18-19 July in Vienna. That Meeting was the last one during the ITER EDA. This volume contains records of these Meetings, including: Records of decisions; List of attendees; ITER EDA status report; ITER EDA technical activities report; MAC report and advice; Final report of ITER EDA; and Press release

  14. MOS voltage automatic tuning circuit

    OpenAIRE

    李, 田茂; 中田, 辰則; 松本, 寛樹

    2004-01-01

    Abstract ###Automatic tuning circuit adjusts frequency performance to compensate for the process variation. Phase locked ###loop (PLL) is a suitable oscillator for the integrated circuit. It is a feedback system that compares the input ###phase with the output phase. It can make the output frequency equal to the input frequency. In this paper, PLL ###fomed of MOSFET's is presented.The presented circuit consists of XOR circuit, Low-pass filter and Relaxation ###Oscillator. On PSPICE simulation...

  15. Embodied Tuning

    DEFF Research Database (Denmark)

    Mortensen, Christian Hviid

    web accessible archives or through listening kiosks in the exhibition. Neither one takes advantage of the unique affordances of the physicality of an exhibition. Instead they most often rely on users clicking through menus, playlists and folders. We therefore propose an alternative way of exhibiting...... bodies as a metaphorical radio tuning dial. We tested the concept in a public exhibition at the Media Museum in Denmark. A small qualitative user study conducted in the exhibition shows promise for this type of immersive experience. The users however tend to perceive it as a unique and finite experience...... radio heritage where users move around and explore the physical room. We implemented a simple low-cost prototype system called Exaudimus that uses webcams to track visitors in a gallery. Using Exaudimus we position audio around the gallery allowing users to search for the audio streams using their own...

  16. Audio Feedback -- Better Feedback?

    Science.gov (United States)

    Voelkel, Susanne; Mello, Luciane V.

    2014-01-01

    National Student Survey (NSS) results show that many students are dissatisfied with the amount and quality of feedback they get for their work. This study reports on two case studies in which we tried to address these issues by introducing audio feedback to one undergraduate (UG) and one postgraduate (PG) class, respectively. In case study one…

  17. Tune variations in the Large Hadron Collider

    Science.gov (United States)

    Aquilina, N.; Giovannozzi, M.; Lamont, M.; Sammut, N.; Steinhagen, R.; Todesco, E.; Wenninger, J.

    2015-04-01

    The horizontal and vertical betatron tunes of the Large Hadron Collider (LHC) mainly depend on the strength of the quadrupole magnets, but are also affected by the quadrupole component in the main dipoles. In case of systematic misalignments, the sextupole component from the main dipoles and sextupole corrector magnets also affect the tunes due to the feed down effect. During the first years of operation of the LHC, the tunes have been routinely measured and corrected through either a feedback or a feed forward system. In this paper, the evolution of the tunes during injection, ramp and flat top are reconstructed from the beam measurements and the settings of the tune feedback loop and of the feed forward corrections. This gives the obtained precision of the magnetic model of the machine with respect to quadrupole and sextupole components. Measurements at the injection plateau show an unexpected large decay whose origin is not understood. This data is discussed together with the time constants and the dependence on previous cycles. We present results of dedicated experiments that show that this effect does not originate from the decay of the main dipole component. During the ramp, the tunes drift by about 0.022. It is shown that this is related to the precision of tracking the quadrupole field in the machine and this effect is reduced to about 0.01 tune units during flat top.

  18. ITER council proceedings: 1998

    International Nuclear Information System (INIS)

    1999-01-01

    This volume contains documents of the 13th and the 14th ITER council meeting as well as of the 1st extraordinary ITER council meeting. Documents of the ITER meetings held in Vienna and Yokohama during 1998 are also included. The contents include an outline of the ITER objectives, the ITER parameters and design overview as well as operating scenarios and plasma performance. Furthermore, design features, safety and environmental characteristics are given

  19. Buckling feedback of the spectral calculations

    International Nuclear Information System (INIS)

    Jing Xingqing; Shan Wenzhi; Luo Jingyu

    1992-01-01

    This paper studies the problems about buckling feedback of spectral calculations in physical calculations of the reactor and presents a useful method by which the buckling feedback of spectral calculations is implemented. The effect of the buckling feedback in spectra and the broad group cross section, convergence of buckling feedback iteration and the effect of the spectral zones dividing are discussed in the calculations. This method has been used for the physical design of HTR-10 MW Test Module

  20. Astronomical tunings of the Oligocene-Miocene transition from Pacific Ocean Site U1334 and implications for the carbon cycle

    Science.gov (United States)

    Beddow, Helen M.; Liebrand, Diederik; Wilson, Douglas S.; Hilgen, Frits J.; Sluijs, Appy; Wade, Bridget S.; Lourens, Lucas J.

    2018-03-01

    Astronomical tuning of sediment sequences requires both unambiguous cycle pattern recognition in climate proxy records and astronomical solutions, as well as independent information about the phase relationship between these two. Here we present two different astronomically tuned age models for the Oligocene-Miocene transition (OMT) from Integrated Ocean Drilling Program Site U1334 (equatorial Pacific Ocean) to assess the effect tuning has on astronomically calibrated ages and the geologic timescale. These alternative age models (roughly from ˜ 22 to ˜ 24 Ma) are based on different tunings between proxy records and eccentricity: the first age model is based on an aligning CaCO3 weight (wt%) to Earth's orbital eccentricity, and the second age model is based on a direct age calibration of benthic foraminiferal stable carbon isotope ratios (δ13C) to eccentricity. To independently test which tuned age model and associated tuning assumptions are in best agreement with independent ages based on tectonic plate-pair spreading rates, we assign the tuned ages to magnetostratigraphic reversals identified in deep-marine magnetic anomaly profiles. Subsequently, we compute tectonic plate-pair spreading rates based on the tuned ages. The resultant alternative spreading-rate histories indicate that the CaCO3 tuned age model is most consistent with a conservative assumption of constant, or linearly changing, spreading rates. The CaCO3 tuned age model thus provides robust ages and durations for polarity chrons C6Bn.1n-C7n.1r, which are not based on astronomical tuning in the latest iteration of the geologic timescale. Furthermore, it provides independent evidence that the relatively large (several 10 000 years) time lags documented in the benthic foraminiferal isotope records relative to orbital eccentricity constitute a real feature of the Oligocene-Miocene climate system and carbon cycle. The age constraints from Site U1334 thus indicate that the delayed responses of the

  1. ITER Council proceedings: 1993

    International Nuclear Information System (INIS)

    1994-01-01

    Records of the third ITER Council Meeting (IC-3), held on 21-22 April 1993, in Tokyo, Japan, and the fourth ITER Council Meeting (IC-4) held on 29 September - 1 October 1993 in San Diego, USA, are presented, giving essential information on the evolution of the ITER Engineering Design Activities (EDA), such as the text of the draft of Protocol 2 further elaborated in ''ITER EDA Agreement and Protocol 2'' (ITER EDA Documentation Series No. 5), recommendations on future work programmes: a description of technology R and D tasks; the establishment of a trust fund for the ITER EDA activities; arrangements for Visiting Home Team Personnel; the general framework for the involvement of other countries in the ITER EDA; conditions for the involvement of Canada in the Euratom Contribution to the ITER EDA; and other attachments as parts of the Records of Decision of the aforementioned ITER Council Meetings

  2. ITER council proceedings: 2000

    International Nuclear Information System (INIS)

    2001-01-01

    No ITER Council Meetings were held during 2000. However, two ITER EDA Meetings were held, one in Tokyo, January 19-20, and one in Moscow, June 29-30. The parties participating in these meetings were those that partake in the extended ITER EDA, namely the EU, the Russian Federation, and Japan. This document contains, a/o, the records of these meetings, the list of attendees, the agenda, the ITER EDA Status Reports issued during these meetings, the TAC (Technical Advisory Committee) reports and recommendations, the MAC Reports and Advice (also for the July 1999 Meeting), the ITER-FEAT Outline Design Report, the TAC Reports and Recommendations both meetings), Site requirements and Site Design Assumptions, the Tentative Sequence of technical Activities 2000-2001, Report of the ITER SWG-P2 on Joint Implementation of ITER, EU/ITER Canada Proposal for New ITER Identification

  3. ITER council proceedings: 1995

    International Nuclear Information System (INIS)

    1996-01-01

    Records of the 8. ITER Council Meeting (IC-8), held on 26-27 July 1995, in San Diego, USA, and the 9. ITER Council Meeting (IC-9) held on 12-13 December 1995, in Garching, Germany, are presented, giving essential information on the evolution of the ITER Engineering Design Activities (EDA) and the ITER Interim Design Report Package and Relevant Documents. Figs, tabs

  4. ITER EDA technical activities

    International Nuclear Information System (INIS)

    Aymar, R.

    1998-01-01

    Six years of technical work under the ITER EDA Agreement have resulted in a design which constitutes a complete description of the ITER device and of its auxiliary systems and facilities. The ITER Council commented that the Final Design Report provides the first comprehensive design of a fusion reactor based on well established physics and technology

  5. ITER radio frequency systems

    International Nuclear Information System (INIS)

    Bosia, G.

    1998-01-01

    Neutral Beam Injection and RF heating are two of the methods for heating and current drive in ITER. The three ITER RF systems, which have been developed during the EDA, offer several complementary services and are able to fulfil ITER operational requirements

  6. ITER council proceedings: 1999

    International Nuclear Information System (INIS)

    1999-01-01

    In 1999 the ITER meeting in Cadarache (10-11 March 1999) and the Programme Directors Meeting in Grenoble (28-29 July 1999) took place. Both meetings were exclusively devoted to ITER engineering design activities and their agendas covered all issues important for the development of ITER. This volume presents the documents of these two important meetings

  7. ITER council proceedings: 1996

    International Nuclear Information System (INIS)

    1997-01-01

    Records of the 10. ITER Council Meeting (IC-10), held on 26-27 July 1996, in St. Petersburg, Russia, and the 11. ITER Council Meeting (IC-11) held on 17-18 December 1996, in Tokyo, Japan, are presented, giving essential information on the evolution of the ITER Engineering Design Activities (EDA) and the cost review and safety analysis. Figs, tabs

  8. Musical experience sharpens human cochlear tuning.

    Science.gov (United States)

    Bidelman, Gavin M; Nelms, Caitlin; Bhagat, Shaum P

    2016-05-01

    The mammalian cochlea functions as a filter bank that performs a spectral, Fourier-like decomposition on the acoustic signal. While tuning can be compromised (e.g., broadened with hearing impairment), whether or not human cochlear frequency resolution can be sharpened through experiential factors (e.g., training or learning) has not yet been established. Previous studies have demonstrated sharper psychophysical tuning curves in trained musicians compared to nonmusicians, implying superior peripheral tuning. However, these findings are based on perceptual masking paradigms, and reflect engagement of the entire auditory system rather than cochlear tuning, per se. Here, by directly mapping physiological tuning curves from stimulus frequency otoacoustic emissions (SFOAEs)-cochlear emitted sounds-we show that estimates of human cochlear tuning in a high-frequency cochlear region (4 kHz) is further sharpened (by a factor of 1.5×) in musicians and improves with the number of years of their auditory training. These findings were corroborated by measurements of psychophysical tuning curves (PTCs) derived via simultaneous masking, which similarly showed sharper tuning in musicians. Comparisons between SFOAE and PTCs revealed closer correspondence between physiological and behavioral curves in musicians, indicating that tuning is also more consistent between different levels of auditory processing in trained ears. Our findings demonstrate an experience-dependent enhancement in the resolving power of the cochlear sensory epithelium and the spectral resolution of human hearing and provide a peripheral account for the auditory perceptual benefits observed in musicians. Both local and feedback (e.g., medial olivocochlear efferent) mechanisms are discussed as potential mechanisms for experience-dependent tuning. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. An automatically tuning intrusion detection system.

    Science.gov (United States)

    Yu, Zhenwei; Tsai, Jeffrey J P; Weigert, Thomas

    2007-04-01

    An intrusion detection system (IDS) is a security layer used to detect ongoing intrusive activities in information systems. Traditionally, intrusion detection relies on extensive knowledge of security experts, in particular, on their familiarity with the computer system to be protected. To reduce this dependence, various data-mining and machine learning techniques have been deployed for intrusion detection. An IDS is usually working in a dynamically changing environment, which forces continuous tuning of the intrusion detection model, in order to maintain sufficient performance. The manual tuning process required by current systems depends on the system operators in working out the tuning solution and in integrating it into the detection model. In this paper, an automatically tuning IDS (ATIDS) is presented. The proposed system will automatically tune the detection model on-the-fly according to the feedback provided by the system operator when false predictions are encountered. The system is evaluated using the KDDCup'99 intrusion detection dataset. Experimental results show that the system achieves up to 35% improvement in terms of misclassification cost when compared with a system lacking the tuning feature. If only 10% false predictions are used to tune the model, the system still achieves about 30% improvement. Moreover, when tuning is not delayed too long, the system can achieve about 20% improvement, with only 1.3% of the false predictions used to tune the model. The results of the experiments show that a practical system can be built based on ATIDS: system operators can focus on verification of predictions with low confidence, as only those predictions determined to be false will be used to tune the detection model.

  10. Giving feedback.

    Science.gov (United States)

    Thomas, Jane DeLima; Arnold, Robert M

    2011-02-01

    Giving feedback is a core element of medical education, one that is gaining attention but with a thin evidence base to guide medical educators. This review provides a definition of feedback and its purpose, selectively reviews the literature regarding educators' and learners' attitudes toward feedback, and provides an algorithm for giving feedback. The authors discuss the parallels between giving feedback and breaking bad news, emphasizing the importance of titrating the amount of information given, attending to affect, and making a plan for next steps. Special considerations for giving feedback in palliative care are highlighted, including the effect of heightened emotion in the clinical encounter and the difficulties of giving feedback about communication skills.

  11. ITER-FEAT safety

    International Nuclear Information System (INIS)

    Gordon, C.W.; Bartels, H.-W.; Honda, T.; Raeder, J.; Topilski, L.; Iseli, M.; Moshonas, K.; Taylor, N.; Gulden, W.; Kolbasov, B.; Inabe, T.; Tada, E.

    2001-01-01

    Safety has been an integral part of the design process for ITER since the Conceptual Design Activities of the project. The safety approach adopted in the ITER-FEAT design and the complementary assessments underway, to be documented in the Generic Site Safety Report (GSSR), are expected to help demonstrate the attractiveness of fusion and thereby set a good precedent for future fusion power reactors. The assessments address ITER's radiological hazards taking into account fusion's favourable safety characteristics. The expectation that ITER will need regulatory approval has influenced the entire safety design and assessment approach. This paper summarises the ITER-FEAT safety approach and assessments underway. (author)

  12. ITER council proceedings: 1997

    International Nuclear Information System (INIS)

    1997-01-01

    This volume of the ITER EDA Documentation Series presents records of the 12th ITER Council Meeting, IC-12, which took place on 23-24 July, 1997 in Tampere, Finland. The Council received from the Parties (EU, Japan, Russia, US) positive responses on the Detailed Design Report. The Parties stated their willingness to contribute to fulfil their obligations in contributing to the ITER EDA. The summary discussions among the Parties led to the consensus that in July 1998 the ITER activities should proceed for additional three years with a general intent to enable an efficient start of possible, future ITER construction

  13. Upgrades to PEP-II Tune Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Alan S.

    2002-07-30

    The tune monitors for the two-ring PEP-II collider convert signals from one set of four BPM-type pickup buttons per ring into horizontal and vertical differences, which are then downconverted from 952 MHz (twice the RF) to baseband. Two-channel 10-MHz FFT spectrum analyzers show spectra in X-window displays in the Control Room, to assist PEP operators. When operating with the original system near the beam-beam limit, collisions broadened and flattened the tune peaks, often bringing them near the noise floor. We recently installed new downconverters that increase the signal-to-noise ratio by about 5 dB. In addition, we went from one to two sets of pickups per ring, near focusing and defocusing quadrupoles, so that signals for both planes originate at locations with large amplitudes. We also have just installed a tune tracker, based on a digital lock-in amplifier (one per tune plane) that is controlled by an EPICS software feedback loop. The tracker monitors the phase of the beam's response to a sinusoidal excitation, and adjusts the drive frequency to track the middle of the 1 go-degree phase transition across the tune resonance. We plan next to test an outer loop controlling the tune quadrupoles based on this tune measurement.

  14. Upgrades to PEP-II Tune Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Alan S.

    2002-07-30

    The tune monitors for the two-ring PEP-II collider convert signals from one set of four BPM-type pickup buttons per ring into horizontal and vertical differences, which are then downconverted from 952 MHz (twice the RF) to baseband. Two-channel l0-MHz FFT spectrum analyzers show spectra in X-window displays in the Control Room, to assist PEP operators. When operating with the original system near the beam-beam limit, collisions broadened and flattened the tune peaks, often bringing them near the noise floor. We recently installed new downconverters that increase the signal-to-noise ratio by about 5 dB. In addition, we went from one to two sets of pickups per ring, near focusing and defocusing quadrupoles, so that signals for both planes originate at locations with large amplitudes. We also have just installed a tune tracker, based on a digital lock-in amplifier (one per tune plane) that is controlled by an EPICS software feedback loop. The tracker monitors the phase of the beam's response to a sinusoidal excitation, and adjusts the drive frequency to track the middle of the 180-degree phase transition across the tune resonance. We plan next to test an outer loop controlling the tune quadrupoles based on this tune measurement.

  15. Upgrades to PEP-II tune measurements

    International Nuclear Information System (INIS)

    Fisher, Alan S.; Petree, Mark; Wienands, Uli; Allison, Stephanie; Laznovsky, Michael; Seeman, Michael; Robin, Jolene

    2002-01-01

    The tune monitors for the two-ring PEP-II collider convert signals from one set of four BPM-type pickup buttons per ring into horizontal and vertical differences, which are then downconverted from 952 MHz (twice the RF) to baseband. Two-channel 10-MHz FFT spectrum analyzers show spectra in X-window displays in the Control Room, to assist PEP operators. When operating with the original system near the beam-beam limit, collisions broadened and flattened the tune peaks, often bringing them near the noise floor. We recently installed new downconverters that increase the signal-to-noise ratio by about 5 dB. In addition, we went from one to two sets of pickups per ring, near focusing and defocusing quadrupoles, so that signals for both planes originate at locations with large amplitudes. We also have just installed a tune tracker, based on a digital lock-in amplifier (one per tune plane) that is controlled by an EPICS software feedback loop. The tracker monitors the phase of the beam's response to a sinusoidal excitation, and adjusts the drive frequency to track the middle of the 180-degree phase transition across the tune resonance. We plan next to test an outer loop controlling the tune quadrupoles based on this tune measurement

  16. Practical tuning for Oracle

    International Nuclear Information System (INIS)

    Kwon, Sun Yong

    2005-02-01

    This book deals with tuning for oracle application, which consists of twenty two chapters. These are the contents of this book : what is tuning?, procedure of tuning, collection of performance data using stats pack, collection of performance data in real time, disk IO dispersion, architecture on Index, partition and IOT, optimization of cluster Factor, optimizer, analysis on plan of operation, selection of Index, tuning of Index, parallel processing architecture, DML, analytic function join method, join type, analysis of application, Lock architecture, SGA architecture and wait event and segment tuning.

  17. ITER test programme

    International Nuclear Information System (INIS)

    Abdou, M.; Baker, C.; Casini, G.

    1991-01-01

    ITER has been designed to operate in two phases. The first phase which lasts for 6 years, is devoted to machine checkout and physics testing. The second phase lasts for 8 years and is devoted primarily to technology testing. This report describes the technology test program development for ITER, the ancillary equipment outside the torus necessary to support the test modules, the international collaboration aspects of conducting the test program on ITER, the requirements on the machine major parameters and the R and D program required to develop the test modules for testing in ITER. 15 refs, figs and tabs

  18. United States rejoin ITER

    International Nuclear Information System (INIS)

    Roberts, M.

    2003-01-01

    Upon pressure from the United States Congress, the US Department of Energy had to withdraw from further American participation in the ITER Engineering Design Activities after the end of its commitment to the EDA in July 1998. In the years since that time, changes have taken place in both the ITER activity and the US fusion community's position on burning plasma physics. Reflecting the interest in the United States in pursuing burning plasma physics, the DOE's Office of Science commissioned three studies as part of its examination of the option of entering the Negotiations on the Agreement on the Establishment of the International Fusion Energy Organization for the Joint Implementation of the ITER Project. These were a National Academy Review Panel Report supporting the burning plasma mission; a Fusion Energy Sciences Advisory Committee (FESAC) report confirming the role of ITER in achieving fusion power production, and The Lehman Review of the ITER project costing and project management processes (for the latter one, see ITER CTA Newsletter, no. 15, December 2002). All three studies have endorsed the US return to the ITER activities. This historical decision was announced by DOE Secretary Abraham during his remarks to employees of the Department's Princeton Plasma Physics Laboratory. The United States will be working with the other Participants in the ITER Negotiations on the Agreement and is preparing to participate in the ITA

  19. PERI auto-tuning

    International Nuclear Information System (INIS)

    Bailey, D H; Williams, S; Chame, J; Chen, C; Hall, M; Dongarra, J; Moore, S; Seymour, K; You, H; Hollingsworth, J K; Tiwari, A; Hovland, P; Shin, J

    2008-01-01

    The enormous and growing complexity of today's high-end systems has increased the already significant challenges of obtaining high performance on equally complex scientific applications. Application scientists are faced with a daunting challenge in tuning their codes to exploit performance-enhancing architectural features. The Performance Engineering Research Institute (PERI) is working toward the goal of automating portions of the performance tuning process. This paper describes PERI's overall strategy for auto-tuning tools and recent progress in both building auto-tuning tools and demonstrating their success on kernels, some taken from large-scale applications

  20. ITER at Cadarache; ITER a Cadarache

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-06-15

    This public information document presents the ITER project (International Thermonuclear Experimental Reactor), the definition of the fusion, the international cooperation and the advantages of the project. It presents also the site of Cadarache, an appropriate scientifical and economical environment. The last part of the documentation recalls the historical aspect of the project and the today mobilization of all partners. (A.L.B.)

  1. ITER council proceedings: 1992

    International Nuclear Information System (INIS)

    1994-01-01

    At the signing of the ITER EDA Agreement on July, 1992, each of the Parties presented to the Director General the names of their designated members of the ITER Council. Upon receiving those names, the Director General stated that the ITER Engineering Design Activities were ''ready to begin''. The next step in this process was the convening of the first meeting of the ITER Council. The first meeting of the Council, held in Vienna, was opened by Director General Hans Blix. The second meeting was held in Moscow, the formal seat of the Council. This volume presents records of these first two Council meetings and, together with the previous volumes on the text of the Agreement and Protocol 1 and the preparations for their signing respectively, represents essential information on the evolution of the ITER EDA

  2. ITER CTA newsletter. No. 3

    International Nuclear Information System (INIS)

    2001-11-01

    This ITER CTA newsletter comprises reports of Dr. P. Barnard, Iter Canada Chairman and CEO, about the progress of the first formal ITER negotiations and about the demonstration of details of Canada's bid on ITER workshops, and Dr. V. Vlasenkov, Project Board Secretary, about the meeting of the ITER CTA project board

  3. Tuning of active vibration controllers for ACTEX by genetic algorithm

    Science.gov (United States)

    Kwak, Moon K.; Denoyer, Keith K.

    1999-06-01

    This paper is concerned with the optimal tuning of digitally programmable analog controllers on the ACTEX-1 smart structures flight experiment. The programmable controllers for each channel include a third order Strain Rate Feedback (SRF) controller, a fifth order SRF controller, a second order Positive Position Feedback (PPF) controller, and a fourth order PPF controller. Optimal manual tuning of several control parameters can be a difficult task even though the closed-loop control characteristics of each controller are well known. Hence, the automatic tuning of individual control parameters using Genetic Algorithms is proposed in this paper. The optimal control parameters of each control law are obtained by imposing a constraint on the closed-loop frequency response functions using the ACTEX mathematical model. The tuned control parameters are then uploaded to the ACTEX electronic control electronics and experiments on the active vibration control are carried out in space. The experimental results on ACTEX will be presented.

  4. Adaptable Iterative and Recursive Kalman Filter Schemes

    Science.gov (United States)

    Zanetti, Renato

    2014-01-01

    Nonlinear filters are often very computationally expensive and usually not suitable for real-time applications. Real-time navigation algorithms are typically based on linear estimators, such as the extended Kalman filter (EKF) and, to a much lesser extent, the unscented Kalman filter. The Iterated Kalman filter (IKF) and the Recursive Update Filter (RUF) are two algorithms that reduce the consequences of the linearization assumption of the EKF by performing N updates for each new measurement, where N is the number of recursions, a tuning parameter. This paper introduces an adaptable RUF algorithm to calculate N on the go, a similar technique can be used for the IKF as well.

  5. ITER days in Moscow

    International Nuclear Information System (INIS)

    Golubchikov, L.

    2001-01-01

    In connection with the successful completion of the Engineering Design of the International Thermonuclear Reactor (ITER) and the 50th anniversary of fusion research in the USSR, the Ministry of the Russian Federation for Atomic Energy (Minatom) with the participation of the Russian Academy of Sciences, organized the International Symposium 'ITER days in Moscow' on 7-8 June 2001. About 250 people from more than 20 states took part in the Meeting. The participants welcomed the R and D results of the ITER project and considered it as a necessary step to establish a basis for a fusion energy source. There were also some scientific presentations on the following topics: ITER physics basis; Effect of fusion research on general physics; Fusion power reactors; US interests in burning plasma

  6. ITER definition phase

    International Nuclear Information System (INIS)

    1989-01-01

    The International Thermonuclear Experimental Reactor (ITER) is envisioned as a fusion device which would demonstrate the scientific and technological feasibility of fusion power. As a first step towards achieving this goal, the European Community, Japan, the Soviet Union, and the United States of America have entered into joint conceptual design activities under the auspices of the International Atomic Energy Agency. A brief summary of the Definition Phase of ITER activities is contained in this report. Included in this report are the background, objectives, organization, definition phase activities, and research and development plan of this endeavor in international scientific collaboration. A more extended technical summary is contained in the two-volume report, ''ITER Concept Definition,'' IAEA/ITER/DS/3. 2 figs, 2 tabs

  7. Power converters for ITER

    CERN Document Server

    Benfatto, I

    2006-01-01

    The International Thermonuclear Experimental Reactor (ITER) is a thermonuclear fusion experiment designed to provide long deuterium– tritium burning plasma operation. After a short description of ITER objectives, the main design parameters and the construction schedule, the paper describes the electrical characteristics of the French 400 kV grid at Cadarache: the European site proposed for ITER. Moreover, the paper describes the main requirements and features of the power converters designed for the ITER coil and additional heating power supplies, characterized by a total installed power of about 1.8 GVA, modular design with basic units up to 90 MVA continuous duty, dc currents up to 68 kA, and voltages from 1 kV to 1 MV dc.

  8. Approximate iterative algorithms

    CERN Document Server

    Almudevar, Anthony Louis

    2014-01-01

    Iterative algorithms often rely on approximate evaluation techniques, which may include statistical estimation, computer simulation or functional approximation. This volume presents methods for the study of approximate iterative algorithms, providing tools for the derivation of error bounds and convergence rates, and for the optimal design of such algorithms. Techniques of functional analysis are used to derive analytical relationships between approximation methods and convergence properties for general classes of algorithms. This work provides the necessary background in functional analysis a

  9. ITER EDA and technology

    International Nuclear Information System (INIS)

    Baker, C.C.

    2001-01-01

    The year 1998 was the culmination of the six-year Engineering Design Activities (EDA) of the International Thermonuclear Experimental Reactor (ITER) Project. The EDA results in design and validating technology R and D, plus the associated effort in voluntary physics research, is a significant achievement and major milestone in the history of magnetic fusion energy development. Consequently, the ITER EDA was a major theme at this Conference, contributing almost 40 papers

  10. ITER explorations started

    International Nuclear Information System (INIS)

    Golubchikov, L.

    2000-01-01

    Opening this first Explorers' Meeting, Minister Adamov welcomed the participants, thanked the ITER parties for their positive response to his invitation and expressed the desire of the Russian Federation to see ITER realized, stressing the importance of continued progress with the project as an outstanding example of international scientific co-operation. During the meeting, the exploration tasks were discussed and agreed upon, as well as the work plan and schedule

  11. Formativ Feedback

    DEFF Research Database (Denmark)

    Hyldahl, Kirsten Kofod

    Denne bog undersøger, hvordan lærere kan anvende feedback til at forbedre undervisningen i klasselokalet. I denne sammenhæng har John Hattie, professor ved Melbourne Universitet, udviklet en model for feedback, hvilken er baseret på synteser af meta-analyser. I 2009 udgav han bogen "Visible...

  12. ITER Status and Plans

    Science.gov (United States)

    Greenfield, Charles M.

    2017-10-01

    The US Burning Plasma Organization is pleased to welcome Dr. Bernard Bigot, who will give an update on progress in the ITER Project. Dr. Bigot took over as Director General of the ITER Organization in early 2015 following a distinguished career that included serving as Chairman and CEO of the French Alternative Energies and Atomic Energy Commission and as High Commissioner for ITER in France. During his tenure at ITER the project has moved into high gear, with rapid progress evident on the construction site and preparation of a staged schedule and a research plan leading from where we are today through all the way to full DT operation. In an unprecedented international effort, seven partners ``China, the European Union, India, Japan, Korea, Russia and the United States'' have pooled their financial and scientific resources to build the biggest fusion reactor in history. ITER will open the way to the next step: a demonstration fusion power plant. All DPP attendees are welcome to attend this ITER town meeting.

  13. iTunes music

    CERN Document Server

    Katz, Bob

    2013-01-01

    Apple's exciting new Mastered for iTunes (MFiT) initiative, introduced in early 2012, introduces new possibilities for delivering high-quality audio. For the first time, record labels and program producers are encouraged to deliver audio materials to iTunes in a high resolution format, which can produce better-sounding masters. In iTunes Music, author and world-class mastering engineer Bob Katz starts out with the basics, surveys the recent past, and brings you quickly up to the present-where the current state of digital audio is bleak. Katz explains the evolution of

  14. Java performance tuning

    CERN Document Server

    Shirazi, Jack

    2003-01-01

    Performance has been an important issue for Java developers ever since the first version hit the streets. Over the years, Java performance has improved dramatically, but tuning is essential to get the best results, especially for J2EE applications. You can never have code that runs too fast. Java Peformance Tuning, 2nd edition provides a comprehensive and indispensable guide to eliminating all types of performance problems. Using many real-life examples to work through the tuning process in detail, JPT shows how tricks such as minimizing object creation and replacing strings with arrays can

  15. Robust Self Tuning Controllers

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad

    1985-01-01

    The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...... has several operation modes and a detector for controlling the mode. A special self tuning controller has been developed to regulate plant with changing time delay.......The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...

  16. TUNE: Compiler-Directed Automatic Performance Tuning

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Mary [University of Utah

    2014-09-18

    This project has developed compiler-directed performance tuning technology targeting the Cray XT4 Jaguar system at Oak Ridge, which has multi-core Opteron nodes with SSE-3 SIMD extensions, and the Cray XE6 Hopper system at NERSC. To achieve this goal, we combined compiler technology for model-guided empirical optimization for memory hierarchies with SIMD code generation, which have been developed by the PIs over the past several years. We examined DOE Office of Science applications to identify performance bottlenecks and apply our system to computational kernels that operate on dense arrays. Our goal for this performance-tuning technology has been to yield hand-tuned levels of performance on DOE Office of Science computational kernels, while allowing application programmers to specify their computations at a high level without requiring manual optimization. Overall, we aim to make our technology for SIMD code generation and memory hierarchy optimization a crucial component of high-productivity Petaflops computing through a close collaboration with the scientists in national laboratories.

  17. ITER CTA newsletter. No. 2

    International Nuclear Information System (INIS)

    2001-10-01

    This ITER CTA newsletter contains results of the ITER toroidal field model coil project presented by ITER EU Home Team (Garching) and an article in commemoration of the late Dr. Charles Maisonnier, one of the former leaders of ITER who made significant contributions to its development

  18. Betatron tune measurement

    International Nuclear Information System (INIS)

    Dinev, D.

    2001-01-01

    On the basis of the comparative review of the methods for the betatron tune measurement in cyclic accelerators of synchrotrons type, the research of these methods is carried out from the point of view of their applicability to Nuclotron. Both methods using measurement of the statistical fluctuations of the beam current (Schottky noise) and methods using coherent beam excitation have been discussed. The emphasis is on the final results of importance for the tune measurement practice. Signal processing is briefly discussed too

  19. RF Design and Tuning of Linac4 RFQ

    CERN Document Server

    France, A C; Piquet, O; Rossi, C

    2012-01-01

    Linac4 is scheduled to deliver 160 MeV H– beam to LHC injection chain by year 2015. The first stage of Linac4 is a 352 MHz, 3-meter long Radio Frequency Quadrupole (RFQ) accelerator [1]. It will accelerate the 70 mA, 45 keV H– beam from the RF source up to 3 MeV energy. Fabrication of RFQ, which started in 2009, is completed [2] and tuning operations are in progress. RF controls performed at each fabrication step have shown that RFQ electrical parameters are well within bounds specified after envelope of fabrication tolerances. Tuning operations have started with adjustment of so-called quadrupole rods inserted in end plates, in order to achieve adequate voltage boundary conditions at both RFQ ends. A preliminary slug tuning test demonstrates voltage percent accuracy after a few slug tuning iterations.

  20. ITER tokamak device

    International Nuclear Information System (INIS)

    Doggett, J.; Salpietro, E.; Shatalov, G.

    1991-01-01

    The results of the Conceptual Design Activities for the International Thermonuclear Experimental Reactor (ITER) are summarized. These activities, carried out between April 1988 and December 1990, produced a consistent set of technical characteristics and preliminary plans for co-ordinated research and development support of ITER; and a conceptual design, a description of design requirements and a preliminary construction schedule and cost estimate. After a description of the design basis, an overview is given of the tokamak device, its auxiliary systems, facility and maintenance. The interrelation and integration of the various subsystems that form the ITER tokamak concept are discussed. The 16 ITER equatorial port allocations, used for nuclear testing, diagnostics, fuelling, maintenance, and heating and current drive, are given, as well as a layout of the reactor building. Finally, brief descriptions are given of the major ITER sub-systems, i.e., (i) magnet systems (toroidal and poloidal field coils and cryogenic systems), (ii) containment structures (vacuum and cryostat vessels, machine gravity supports, attaching locks, passive loops and active coils), (iii) first wall, (iv) divertor plate (design and materials, performance and lifetime, a.o.), (v) blanket/shield system, (vi) maintenance equipment, (vii) current drive and heating, (viii) fuel cycle system, and (ix) diagnostics. 11 refs, figs and tabs

  1. Twelfth ITER negotiation meeting

    International Nuclear Information System (INIS)

    2006-01-01

    Delegations from China, European Union, Japan, the Republic of Korea, the Russian Federation and the United States of America gathered on Jeju Island, Korea, on 6 December 2005, to complete their negotiations on an Agreement on the joint implementation of the ITER international fusion energy project. At the start of the Meeting, the Delegations unanimously and enthusiastically welcomed India as a full Party to the ITER venture. A Delegation from India then joined the Meeting and participated fully in the discussions that followed. The seven ITER Delegations also welcomed to the Meeting the newly designated Nominee Director-General for the prospective ITER Organization, Ambassador Kaname Ikeda, who is to take up his duties as leader of the project. Based on the results of intensive working level meetings held throughout the previous week, the Delegations have succeeded in clearing the remaining key issues such as decision-making, intellectual property and management within the prospective ITER Organization and adjustments to the sharing of resources as a result of India's participation, including in particular cost sharing and in-kind contributions, leaving only a few legal points requiring resolution during the final lawyers' meeting to review the text for coherence and internal consistency

  2. Academic Training: The ITER project: technological challenges

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 31 May, 1, 2, 3, June from 11:00 to 12:00 on 31 May and 2, 3, June. From 10:00 to 12:00 on 1 June - Main Auditorium, bldg. 500 The ITER project: technological challenges J. LISTER / CRPP-EPFL, Lausanne, CH and P. BRUZZONE / CRPP-EPFL, Zürich, CH The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the...

  3. Academic Training: The ITER project: technological challenges

    CERN Multimedia

    Françoise Benz

    2005-01-01

    2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 31 May, 1, 2, 3, June from 11:00 to 12:00 on 31 May and 2, 3, June. From 10:00 to 12:00 on 1 June - Main Auditorium, bldg. 500 The ITER project: technological challenges J. LISTER / CRPP-EPFL, Lausanne and P. BRUZZONE / CRPP-EPFL, Zürich The first lecture reminds us of the ITER challenges, presents hard engineering problems, typically due to mechanical forces and thermal loads and identifies where the physics uncertainties play a significant role in the engineering requirements. The second lecture presents soft engineering problems of measuring the plasma parameters, feedback control of the plasma and handling the physics data flow and slow controls data flow from a large experiment like ITER. The last three lectures focus on superconductors for fusion. The third lecture reviews the design criteria and manufacturing methods for 6 milestone-conductors of large fusion devices (T-7, T-15, Tore Supra, LHD, W-7X, ITER). The evolution of the de...

  4. Designing a prototype of the ITER pulse scheduling system

    International Nuclear Information System (INIS)

    Yamamoto, T.; Yonekawa, I.; Ohta, K.; Hosoyama, H.; Hashimoto, Y.; Wallander, A.; Winter, A.; Sugie, T.; Kusama, Y.; Kawano, Y.; Yoshino, R.

    2012-01-01

    Highlights: ► We designed a prototype of the ITER pulse scheduling system. ► Structure of ITER pulse schedules was designed. ► Validation and automatic value assignment functions were adopted. ► A prototype will be implemented in 2011. - Abstract: A prototype of the ITER pulse scheduling system that prepares and manages parameters for ITER plasma operations has been designed. Based on the analyzed requirements on the system, structure of the parameters and necessary functions were determined. Segment and module structures were tuned to the ITER requirements. Three types of validations assure sanity of the parameters. The design limits check and the operation window check verify whether the values of the parameters do not exceed the limits. The consistency check calculates dependency among parameters in accordance with logics described in a scripting language. The ITER pulse scheduling system provides interface with a physics model and simulator. Some abstract physics parameters are converted to engineering parameters with the physics simulation. The results of simulation such as plasma characteristics of specified parameters are also shown to the researchers. The tool to specify the parameters is data-driven. Therefore, it is flexible for changes of number of the parameters. A prototype is being implemented in 2011. Using the prototype, this design will be verified and refined. The evaluation of the prototype will be a basis of the final production of the ITER pulse scheduling system.

  5. Earthly sun called ITER

    International Nuclear Information System (INIS)

    Pozdeyev, Mikhail

    2002-01-01

    Full text: Participating in the film are Academicians Velikhov and Glukhikh, Mr. Filatof, ITER Director from Russia, Mr. Sannikov from Kurchatov Institute. The film tells about the starting point of the project (Mr. Lavrentyev), the pioneers of the project (Academicians Tamme, Sakharov, Artsimovich) and about the situation the project is standing now. Participating in [ITER now are the US, Russia, Japan and the European Union. There are two associated members as well - Kazakhstan and Canada. By now the engineering design phase has been finished. Computer animation used in the video gives us the idea how the first thermonuclear reactor based on famous Russian TOKOMAK works. (author)

  6. Iterated multidimensional wave conversion

    International Nuclear Information System (INIS)

    Brizard, A. J.; Tracy, E. R.; Johnston, D.; Kaufman, A. N.; Richardson, A. S.; Zobin, N.

    2011-01-01

    Mode conversion can occur repeatedly in a two-dimensional cavity (e.g., the poloidal cross section of an axisymmetric tokamak). We report on two novel concepts that allow for a complete and global visualization of the ray evolution under iterated conversions. First, iterated conversion is discussed in terms of ray-induced maps from the two-dimensional conversion surface to itself (which can be visualized in terms of three-dimensional rooms). Second, the two-dimensional conversion surface is shown to possess a symplectic structure derived from Dirac constraints associated with the two dispersion surfaces of the interacting waves.

  7. ITER conceptual design

    International Nuclear Information System (INIS)

    Tomabechi, K.; Gilleland, J.R.; Sokolov, Yu.A.; Toschi, R.

    1991-01-01

    The Conceptual Design Activities of the International Thermonuclear Experimental Reactor (ITER) were carried out jointly by the European Community, Japan, the Soviet Union and the United States of America, under the auspices of the International Atomic Energy Agency. The European Community provided the site for joint work sessions at the Max-Planck-Institut fuer Plasmaphysik in Garching, Germany. The Conceptual Design Activities began in the spring of 1988 and ended in December 1990. The objectives of the activities were to develop the design of ITER, to perform a safety and environmental analysis, to define the site requirements as well as the future research and development needs, to estimate the cost and manpower, and to prepare a schedule for detailed engineering design, construction and operation. On the basis of the investigation and analysis performed, a concept of ITER was developed which incorporated maximum flexibility of the performance of the device and allowed a variety of operating scenarios to be adopted. The heart of the machine is a tokamak having a plasma major radius of 6 m, a plasma minor radius of 2.15 m, a nominal plasma current of 22 MA and a nominal fusion power of 1 GW. The conceptual design can meet the technical objectives of the ITER programme. Because of the success of the Conceptual Design Activities, the Parties are now considering the implementation of the next phase, called the Engineering Design Activities. (author). Refs, figs and tabs

  8. ITER power electrical networks

    International Nuclear Information System (INIS)

    Sejas Portela, S.

    2011-01-01

    The ITER project (International Thermonuclear Experimental Reactor) is an international effort to research and development to design, build and operate an experimental facility to demonstrate the scientific and technological possibility of obtaining useful energy from the physical phenomenon known as nuclear fusion.

  9. ITER-FEAT operation

    International Nuclear Information System (INIS)

    Shimomura, Y.; Huget, M.; Mizoguchi, T.; Murakami, Y.; Polevoi, A.; Shimada, M.; Aymar, R.; Chuyanov, V.; Matsumoto, H.

    2001-01-01

    ITER is planned to be the first fusion experimental reactor in the world operating for research in physics and engineering. The first 10 years' operation will be devoted primarily to physics issues at low neutron fluence and the following 10 years' operation to engineering testing at higher fluence. ITER can accommodate various plasma configurations and plasma operation modes such as inductive high Q modes, long pulse hybrid modes, non-inductive steady-state modes, with large ranges of plasma current, density, beta and fusion power, and with various heating and current drive methods. This flexibility will provide an advantage for coping with uncertainties in the physics database, in studying burning plasmas, in introducing advanced features and in optimizing the plasma performance for the different programme objectives. Remote sites will be able to participate in the ITER experiment. This concept will provide an advantage not only in operating ITER for 24 hours per day but also in involving the world-wide fusion communities and in promoting scientific competition among the Parties. (author)

  10. ITER conceptual design report

    International Nuclear Information System (INIS)

    1991-01-01

    Results of the International Thermonuclear Experimental Reactor (ITER) Conceptual Design Activity (CDA) are reported. This report covers the Terms of Reference for the project: defining the technical specifications, defining future research needs, define site requirements, and carrying out a coordinated research effort coincident with the CDA. Refs, figs and tabs

  11. US ITER Management Plan

    International Nuclear Information System (INIS)

    1991-12-01

    This US ITER Management Plan is the plan for conducting the Engineering Design Activities within the US. The plan applies to all design, analyses, and associated physics and technology research and development (R ampersand D) required to support the program. The plan defines the management considerations associated with these activities. The plan also defines the management controls that the project participants will follow to establish, implement, monitor, and report these activities. The activities are to be conducted by the project in accordance with this plan. The plan will be updated to reflect the then-current management approach required to meet the project objectives. The plan will be reviewed at least annually for possible revision. Section 2 presents the ITER objectives, a brief description of the ITER concept as developed during the Conceptual Design Activities, and comments on the Engineering Design Activities. Section 3 discusses the planned international organization for the Engineering Design Activities, from which the tasks will flow to the US Home Team. Section 4 describes the US ITER management organization and responsibilities during the Engineering Design Activities. Section 5 describes the project management and control to be used to perform the assigned tasks during the Engineering Design Activities. Section 6 presents the references. Several appendices are provided that contain detailed information related to the front material

  12. Iterative List Decoding

    DEFF Research Database (Denmark)

    Justesen, Jørn; Høholdt, Tom; Hjaltason, Johan

    2005-01-01

    We analyze the relation between iterative decoding and the extended parity check matrix. By considering a modified version of bit flipping, which produces a list of decoded words, we derive several relations between decodable error patterns and the parameters of the code. By developing a tree...

  13. ITER at Cadarache

    International Nuclear Information System (INIS)

    2005-06-01

    This public information document presents the ITER project (International Thermonuclear Experimental Reactor), the definition of the fusion, the international cooperation and the advantages of the project. It presents also the site of Cadarache, an appropriate scientifical and economical environment. The last part of the documentation recalls the historical aspect of the project and the today mobilization of all partners. (A.L.B.)

  14. Iterative software kernels

    Energy Technology Data Exchange (ETDEWEB)

    Duff, I.

    1994-12-31

    This workshop focuses on kernels for iterative software packages. Specifically, the three speakers discuss various aspects of sparse BLAS kernels. Their topics are: `Current status of user lever sparse BLAS`; Current status of the sparse BLAS toolkit`; and `Adding matrix-matrix and matrix-matrix-matrix multiply to the sparse BLAS toolkit`.

  15. Active tuned mass damper for damping of offshore wind turbine vibrations

    DEFF Research Database (Denmark)

    Brodersen, Mark Laier; Bjørke, Ann-Sofie; Høgsberg, Jan Becker

    2017-01-01

    An active tuned mass damper (ATMD) is employed for damping of tower vibrations of fixed offshore wind turbines, where the additional actuator force is controlled using feedback from the tower displacement and the relative velocity of the damper mass. An optimum tuning procedure equivalent to the ...

  16. Status of ITER

    International Nuclear Information System (INIS)

    Aymar, R.

    2002-01-01

    At the end of engineering design activities (EDA) in July 2001, all the essential elements became available to make a decision on construction of ITER. A sufficiently detailed and integrated engineering design now exists for a generic site, has been assessed for feasibility, and costed, and essential physics and technology R and D has been carried out to underpin the design choices. Formal negotiations have now begun between the current participants--Canada, Euratom, Japan, and the Russian Federation--on a Joint Implementation Agreement for ITER which also establishes the legal entity to run ITER. These negotiations are supported on technical aspects by Coordinated Technical Activities (CTA), which maintain the integrity of the project, for the good of all participants, and concentrate on preparing for procurement by industry of the longest lead items, and for formal application for a construction license with the host country. This paper highlights the main features of the ITER design. With cryogenically-cooled magnets close to neutron-generating plasma, the design of shielding with adequate access via port plugs for auxiliaries such as heating and diagnostics, and of remote replacement and refurbishing systems for in-vessel components, are particularly interesting nuclear technology challenges. Making a safety case for ITER to satisfy potential regulators and to demonstrate, as far as possible at this stage, the environmental attractiveness of fusion as an energy source, is also important. The paper gives illustrative details on this work, and an update on the progress of technical preparations for construction, as well as the status of the above negotiations

  17. Transverse feedback

    CERN Document Server

    Cornelis, K; Sladen, Jonathan P H; CERN. Geneva. SPS and LEP Division

    1997-01-01

    The aim of these MD's was to set up the transverse feedback for damping in both planes, and to test the charge normalization and gain compensation. The latter is intended to reduce the gain of the feedback for small oscillations in order to improve compatibility with the Q loop. All work was done with 2 x 4 bunches, family A. In the first two MD's the feedback was set up for damping in both planes with charge normalization. In the third, gain compensation was commissioned in the vertical plane with Qv' set to -2. It was found either to increase the level of the m = 0 mode or to leave it unchanged. Under these conditions 6mA total current was accumulated.

  18. Feedback mapping - The curricular cornerstone of an "educational alliance".

    OpenAIRE

    Murdoch-Eaton, D.; Bowen, L.

    2017-01-01

    PURPOSE: The "educational alliance" concept articulates a collaborative framework to facilitate effective feedback through transparency of opportunities aligned with learner stage and intended educational outcomes. Using this framework, we evaluated feedback across a 5 year undergraduate medical program to support embedding a successful learner - teacher "educational alliance". METHOD: A comprehensive mapping exercise used an iterative action research process of source documentary analysis, c...

  19. ITER EDA status

    International Nuclear Information System (INIS)

    Aymar, R.

    2001-01-01

    The Project has focused on drafting the Plant Description Document (PDD), which will be published as the Technical Basis for the ITER Final Design Report (FDR), and its related documentation in time for the ITER review process. The preparations have involved continued intensive detailed design work, analyses and assessments by the Home Teams and the Joint Central Team, who have co-operated closely and efficiently. The main technical document has been completed in time for circulation, as planned, to TAC members for their review at TAC-17 (19-22 February 2001). Some of the supporting documents, such as the Plant Design Specification (PDS), Design Requirements and Guidelines (DRG1 and DRG2), and the Plant Safety Requirement (PSR) are also available for reference in draft form. A summary paper of the PDD for the Council's information is available as a separate document. A new documentation structure for the Project has been established. This hierarchical structure for documentation facilitates the entire organization in a way that allows better change control and avoids duplications. The initiative was intended to make this documentation system valid for the construction and operation phases of ITER. As requested, the Director and the JCT have been assisting the Explorations to plan for future joint technical activities during the Negotiations, and to consider technical issues important for ITER construction and operation for their introduction in the draft of a future joint implementation agreement. As charged by the Explorers, the Director has held discussions with the Home Team Leaders in order to prepare for the staffing of the International Team and Participants Teams during the Negotiations (Co-ordinated Technical Activities, CTA) and also in view of informing all ITER staff about their future directions in a timely fashion. One important element of the work was the completion by the Parties' industries of costing studies of about 83 ''procurement packages

  20. Iterative Algorithms for Nonexpansive Mappings

    Directory of Open Access Journals (Sweden)

    Yao Yonghong

    2008-01-01

    Full Text Available Abstract We suggest and analyze two new iterative algorithms for a nonexpansive mapping in Banach spaces. We prove that the proposed iterative algorithms converge strongly to some fixed point of .

  1. Tuning the Blend

    Science.gov (United States)

    Schaffhauser, Dian

    2012-01-01

    "Tuning the blend" is a phrase that educators hear a lot these days. It refers to finding the correct balance of online activities and face-to-face instruction in hybrid--or blended--courses. Finding a mix that meets the needs of both faculty and students requires experimentation, experience, and constant tweaking. And, as with coffee, the same…

  2. SC tuning fork

    CERN Multimedia

    The tuning fork used to modulate the radiofrequency system of the synchro cyclotron (SC) from 1957 to 1973. This piece is an unused spare part. The SC was the 1st accelerator built at CERN. It operated from August 1957 until it was closed down at the end of 1990. In the SC the magnetic field did not change with time, and the particles were accelerated in successive pulses by a radiofrequency voltage of some 20kV which varied in frequency as they spiraled outwards towards the extraction radius. The frequency varied from 30MHz to about 17Mz in each pulse. The tuning fork vibrated at 55MHz in vacuum in an enclosure which formed a variable capacitor in the tuning circuit of the RF system, allowing the RF to vary over the appropriate range to accelerate protons from the centre of the macine up to 600Mev at extraction radius. In operation the tips of the tuning fork blade had an amplitude of movement of over 1 cm. The SC accelerator underwent extensive improvements from 1973 to 1975, including the installation of a...

  3. Learning to rank from relevance feedback for e-discovery

    NARCIS (Netherlands)

    Lubell-Doughtie, P.; Hofmann, K.

    2012-01-01

    In recall-oriented search tasks retrieval systems are privy to a greater amount of user feedback. In this paper we present a novel method of combining relevance feedback with learning to rank. Our experiments use data from the 2010 TREC Legal track to demonstrate that learning to rank can tune

  4. Resource Usage Protocols for Iterators

    NARCIS (Netherlands)

    Huisman, Marieke; Haack, C.; Müller, P.; Hurlin, C.

    We discuss usage protocols for iterator objects that prevent concurrent modifications of the underlying collection while iterators are in progress. We formalize these protocols in Java-like object interfaces, enriched with separation logic contracts. We present examples of iterator clients and

  5. ITER CTA newsletter. No. 4

    International Nuclear Information System (INIS)

    2001-12-01

    This ITER CTA Newsletter contains information about the organization of the ITER Co-ordinated Technical Activities (CTA) International Team as the follow-up of the ITER CTA project board meeting in Toronto on 7 November 2001. It also includes a summary on the start of the international tokamak physics activity by Dr. D. Campbell, Chair of the ITPA Co-ordinating Committee

  6. Status of the ITER EDA

    International Nuclear Information System (INIS)

    Aymar, R.

    2000-01-01

    This article summarizes progress made in the ITER Engineering Design Activities in the period between the ITER Meeting in Tokyo (January 2000) and June 2000. Topics: Termination of EDA, Joint Central Team and Support, Task Assignments, ITER Physics, Urgent and High Priority Physics Research Areas

  7. Iterative supervirtual refraction interferometry

    KAUST Repository

    Al-Hagan, Ola

    2014-05-02

    In refraction tomography, the low signal-to-noise ratio (S/N) can be a major obstacle in picking the first-break arrivals at the far-offset receivers. To increase the S/N, we evaluated iterative supervirtual refraction interferometry (ISVI), which is an extension of the supervirtual refraction interferometry method. In this method, supervirtual traces are computed and then iteratively reused to generate supervirtual traces with a higher S/N. Our empirical results with both synthetic and field data revealed that ISVI can significantly boost up the S/N of far-offset traces. The drawback is that using refraction events from more than one refractor can introduce unacceptable artifacts into the final traveltime versus offset curve. This problem can be avoided by careful windowing of refraction events.

  8. ITER technical basis

    International Nuclear Information System (INIS)

    2002-01-01

    Following on from the Final Report of the EDA(DS/21), and the summary of the ITER Final Design report(DS/22), the technical basis gives further details of the design of ITER. It is in two parts. The first, the Plant Design specification, summarises the main constraints on the plant design and operation from the viewpoint of engineering and physics assumptions, compliance with safety regulations, and siting requirements and assumptions. The second, the Plant Description Document, describes the physics performance and engineering characteristics of the plant design, illustrates the potential operational consequences foe the locality of a generic site, gives the construction, commissioning, exploitation and decommissioning schedule, and reports the estimated lifetime costing based on data from the industry of the EDA parties

  9. Iterative participatory design

    DEFF Research Database (Denmark)

    Simonsen, Jesper; Hertzum, Morten

    2010-01-01

    The theoretical background in this chapter is information systems development in an organizational context. This includes theories from participatory design, human-computer interaction, and ethnographically inspired studies of work practices. The concept of design is defined as an experimental...... iterative process of mutual learning by designers and domain experts (users), who aim to change the users’ work practices through the introduction of information systems. We provide an illustrative case example with an ethnographic study of clinicians experimenting with a new electronic patient record...... system, focussing on emergent and opportunity-based change enabled by appropriating the system into real work. The contribution to a general core of design research is a reconstruction of the iterative prototyping approach into a general model for sustained participatory design....

  10. Conformable variational iteration method

    Directory of Open Access Journals (Sweden)

    Omer Acan

    2017-02-01

    Full Text Available In this study, we introduce the conformable variational iteration method based on new defined fractional derivative called conformable fractional derivative. This new method is applied two fractional order ordinary differential equations. To see how the solutions of this method, linear homogeneous and non-linear non-homogeneous fractional ordinary differential equations are selected. Obtained results are compared the exact solutions and their graphics are plotted to demonstrate efficiency and accuracy of the method.

  11. Neutron cameras for ITER

    International Nuclear Information System (INIS)

    Johnson, L.C.; Barnes, C.W.; Batistoni, P.

    1998-01-01

    Neutron cameras with horizontal and vertical views have been designed for ITER, based on systems used on JET and TFTR. The cameras consist of fan-shaped arrays of collimated flight tubes, with suitably chosen detectors situated outside the biological shield. The sight lines view the ITER plasma through slots in the shield blanket and penetrate the vacuum vessel, cryostat, and biological shield through stainless steel windows. This paper analyzes the expected performance of several neutron camera arrangements for ITER. In addition to the reference designs, the authors examine proposed compact cameras, in which neutron fluxes are inferred from 16 N decay gammas in dedicated flowing water loops, and conventional cameras with fewer sight lines and more limited fields of view than in the reference designs. It is shown that the spatial sampling provided by the reference designs is sufficient to satisfy target measurement requirements and that some reduction in field of view may be permissible. The accuracy of measurements with 16 N-based compact cameras is not yet established, and they fail to satisfy requirements for parameter range and time resolution by large margins

  12. ITER concept definition. V.2

    International Nuclear Information System (INIS)

    1989-01-01

    Volume II of the two volumes describing the concept definition of the International Thermonuclear Experimental Reactor deals with the ITER concept in technical depth, and covers all areas of design of the ITER tokamak. Included are an assessment of the current database for design, scoping studies, rationale for concepts selection, performance flexibility, the ITER concept, the operations and experimental/testing program, ITER parameters and design phase schedule, and research and development specific to ITER. This latter includes a definition of specific research and development tasks, a division of tasks among members, specific milestones, required results, and schedules. Figs and tabs

  13. ITER CTA newsletter. No. 10

    International Nuclear Information System (INIS)

    2002-07-01

    This ITER CTA newsletter issue comprises the ITER backgrounder, which was approved as an official document by the participants in the Negotiations on the ITER Implementation agreement at their fourth meeting, held in Cadarache from 4-6 June 2002, and information about two ITER meetings: one is the third meeting of the ITER parties' designated Safety Representatives, which took place in Cadarache, France from 6-7 June 2002, and the other is the second meeting of the International Tokamak Physics Activity (ITPA) topical group on diagnostics, which was held at General Atomics, San Diego, USA, from 4-8 March 2002

  14. Model-Free Primitive-Based Iterative Learning Control Approach to Trajectory Tracking of MIMO Systems With Experimental Validation.

    Science.gov (United States)

    Radac, Mircea-Bogdan; Precup, Radu-Emil; Petriu, Emil M

    2015-11-01

    This paper proposes a novel model-free trajectory tracking of multiple-input multiple-output (MIMO) systems by the combination of iterative learning control (ILC) and primitives. The optimal trajectory tracking solution is obtained in terms of previously learned solutions to simple tasks called primitives. The library of primitives that are stored in memory consists of pairs of reference input/controlled output signals. The reference input primitives are optimized in a model-free ILC framework without using knowledge of the controlled process. The guaranteed convergence of the learning scheme is built upon a model-free virtual reference feedback tuning design of the feedback decoupling controller. Each new complex trajectory to be tracked is decomposed into the output primitives regarded as basis functions. The optimal reference input for the control system to track the desired trajectory is next recomposed from the reference input primitives. This is advantageous because the optimal reference input is computed straightforward without the need to learn from repeated executions of the tracking task. In addition, the optimization problem specific to trajectory tracking of square MIMO systems is decomposed in a set of optimization problems assigned to each separate single-input single-output control channel that ensures a convenient model-free decoupling. The new model-free primitive-based ILC approach is capable of planning, reasoning, and learning. A case study dealing with the model-free control tuning for a nonlinear aerodynamic system is included to validate the new approach. The experimental results are given.

  15. Differential Resonant Ring YIG Tuned Oscillator

    Science.gov (United States)

    Parrott, Ronald A.

    2010-01-01

    A differential SiGe oscillator circuit uses a resonant ring-oscillator topology in order to electronically tune the oscillator over multi-octave bandwidths. The oscillator s tuning is extremely linear, because the oscillator s frequency depends on the magnetic tuning of a YIG sphere, whose resonant frequency is equal to a fundamental constant times the DC magnetic field. This extremely simple circuit topology uses two coupling loops connecting a differential pair of SiGe bipolar transistors into a feedback configuration using a YIG tuned filter creating a closed-loop ring oscillator. SiGe device technology is used for this oscillator in order to keep the transistor s 1/f noise to an absolute minimum in order to achieve minimum RF phase noise. The single-end resonant ring oscillator currently has an advantage in fewer parts, but when the oscillation frequency is greater than 16 GHz, the package s parasitic behavior couples energy to the sphere and causes holes and poor phase noise performance. This is because the coupling to the YIG is extremely low, so that the oscillator operates at near the unloaded Q. With the differential resonant ring oscillator, the oscillation currents are just in the YIG coupling mechanisms. The phase noise is even better, and the physical size can be reduced to permit monolithic microwave integrated circuit oscillators. This invention is a YIG tuned oscillator circuit making use of a differential topology to simultaneously achieve an extremely broadband electronic tuning range and ultra-low phase noise. As a natural result of its differential circuit topology, all reactive elements, such as tuning stubs, which limit tuning bandwidth by contributing excessive open loop phase shift, have been eliminated. The differential oscillator s open-loop phase shift is associated with completely non-dispersive circuit elements such as the physical angle of the coupling loops, a differential loop crossover, and the high-frequency phase shift of the n

  16. ITER EDA newsletter. V. 7, no. 7

    International Nuclear Information System (INIS)

    1998-07-01

    This newsletter contains the articles: 'Extraordinary ITER council meeting', 'ITER EDA final safety meeting' and 'Summary report of the 3rd combined workshop of the ITER confinement and transport and ITER confinement database and modeling expert groups'

  17. PID controller tuning using metaheuristic optimization algorithms for benchmark problems

    Science.gov (United States)

    Gholap, Vishal; Naik Dessai, Chaitali; Bagyaveereswaran, V.

    2017-11-01

    This paper contributes to find the optimal PID controller parameters using particle swarm optimization (PSO), Genetic Algorithm (GA) and Simulated Annealing (SA) algorithm. The algorithms were developed through simulation of chemical process and electrical system and the PID controller is tuned. Here, two different fitness functions such as Integral Time Absolute Error and Time domain Specifications were chosen and applied on PSO, GA and SA while tuning the controller. The proposed Algorithms are implemented on two benchmark problems of coupled tank system and DC motor. Finally, comparative study has been done with different algorithms based on best cost, number of iterations and different objective functions. The closed loop process response for each set of tuned parameters is plotted for each system with each fitness function.

  18. A fast iterative scheme for the linearized Boltzmann equation

    Science.gov (United States)

    Wu, Lei; Zhang, Jun; Liu, Haihu; Zhang, Yonghao; Reese, Jason M.

    2017-06-01

    Iterative schemes to find steady-state solutions to the Boltzmann equation are efficient for highly rarefied gas flows, but can be very slow to converge in the near-continuum flow regime. In this paper, a synthetic iterative scheme is developed to speed up the solution of the linearized Boltzmann equation by penalizing the collision operator L into the form L = (L + Nδh) - Nδh, where δ is the gas rarefaction parameter, h is the velocity distribution function, and N is a tuning parameter controlling the convergence rate. The velocity distribution function is first solved by the conventional iterative scheme, then it is corrected such that the macroscopic flow velocity is governed by a diffusion-type equation that is asymptotic-preserving into the Navier-Stokes limit. The efficiency of this new scheme is assessed by calculating the eigenvalue of the iteration, as well as solving for Poiseuille and thermal transpiration flows. We find that the fastest convergence of our synthetic scheme for the linearized Boltzmann equation is achieved when Nδ is close to the average collision frequency. The synthetic iterative scheme is significantly faster than the conventional iterative scheme in both the transition and the near-continuum gas flow regimes. Moreover, due to its asymptotic-preserving properties, the synthetic iterative scheme does not need high spatial resolution in the near-continuum flow regime, which makes it even faster than the conventional iterative scheme. Using this synthetic scheme, with the fast spectral approximation of the linearized Boltzmann collision operator, Poiseuille and thermal transpiration flows between two parallel plates, through channels of circular/rectangular cross sections and various porous media are calculated over the whole range of gas rarefaction. Finally, the flow of a Ne-Ar gas mixture is solved based on the linearized Boltzmann equation with the Lennard-Jones intermolecular potential for the first time, and the difference

  19. ITER EDA newsletter. V. 10, special issue

    International Nuclear Information System (INIS)

    2001-07-01

    This ITER EDA Newsletter includes summaries of the reports of ITER EDA JCT Physics unit about ITER physics R and D during the Engineering Design Activities (EDA), ITER EDA JCT Naka JWC ITER technology R and D during the EDA, and Safety, Environment and Health group of ITER EDA JCT, Garching JWS on EDA activities related to safety

  20. Combining experimental observation and modelling in investigating feedback and emotions in repeated selection tasks

    NARCIS (Netherlands)

    Fischer, A.R.H.; Blommaert, F.J.J.; Midden, C.J.H.

    2005-01-01

    People seem to learn tasks even without formal training. This can be modelled as the outcome of a feedback system that accumulates experience. In this paper we investigate such a feedback system, following an iterative research approach. A feedback loop is specified that is detailed using

  1. Pulsed feedback defers cellular differentiation.

    Directory of Open Access Journals (Sweden)

    Joe H Levine

    2012-01-01

    Full Text Available Environmental signals induce diverse cellular differentiation programs. In certain systems, cells defer differentiation for extended time periods after the signal appears, proliferating through multiple rounds of cell division before committing to a new fate. How can cells set a deferral time much longer than the cell cycle? Here we study Bacillus subtilis cells that respond to sudden nutrient limitation with multiple rounds of growth and division before differentiating into spores. A well-characterized genetic circuit controls the concentration and phosphorylation of the master regulator Spo0A, which rises to a critical concentration to initiate sporulation. However, it remains unclear how this circuit enables cells to defer sporulation for multiple cell cycles. Using quantitative time-lapse fluorescence microscopy of Spo0A dynamics in individual cells, we observed pulses of Spo0A phosphorylation at a characteristic cell cycle phase. Pulse amplitudes grew systematically and cell-autonomously over multiple cell cycles leading up to sporulation. This pulse growth required a key positive feedback loop involving the sporulation kinases, without which the deferral of sporulation became ultrasensitive to kinase expression. Thus, deferral is controlled by a pulsed positive feedback loop in which kinase expression is activated by pulses of Spo0A phosphorylation. This pulsed positive feedback architecture provides a more robust mechanism for setting deferral times than constitutive kinase expression. Finally, using mathematical modeling, we show how pulsing and time delays together enable "polyphasic" positive feedback, in which different parts of a feedback loop are active at different times. Polyphasic feedback can enable more accurate tuning of long deferral times. Together, these results suggest that Bacillus subtilis uses a pulsed positive feedback loop to implement a "timer" that operates over timescales much longer than a cell cycle.

  2. Searching with iterated maps.

    Science.gov (United States)

    Elser, V; Rankenburg, I; Thibault, P

    2007-01-09

    In many problems that require extensive searching, the solution can be described as satisfying two competing constraints, where satisfying each independently does not pose a challenge. As an alternative to tree-based and stochastic searching, for these problems we propose using an iterated map built from the projections to the two constraint sets. Algorithms of this kind have been the method of choice in a large variety of signal-processing applications; we show here that the scope of these algorithms is surprisingly broad, with applications as diverse as protein folding and Sudoku.

  3. Design of PID controllers in double feedback loops for SISO systems with set-point filters.

    Science.gov (United States)

    Vijayan, V; Panda, Rames C

    2012-07-01

    A PID controller is widely used to control industrial processes that are mostly open loop stable or unstable. Selection of proper feedback structure and controller tuning helps to improve the performance of the loop. In this paper a double-feedback loop/method is used to achieve stability and better performance of the process. The internal feedback is used for stabilizing the process and the outer loop is used for good setpoint tracking. An internal model controller (IMC) based PID method is used for tuning the outer loop controller. Autotuning based on relay feedback or the Ziegler-Nichols method can be used for tuning an inner loop controller. A tuning parameter (λ) that is used to tune IMC-PID is used as a time constant of a setpoint filter that is used for reducing the peak overshoot. The method has been tested successfully on many low order processes. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  4. MARTe at FTU: The new feedback control

    Energy Technology Data Exchange (ETDEWEB)

    Boncagni, Luca, E-mail: luca.boncagni@enea.it [EURATOM - ENEA Fusion Association, Frascati Research Centre, Division of Fusion Physics, Rome, Frascati (Italy); Sadeghi, Yahya; Carnevale, Daniele; Di Geronimo, Andrea; Varano, Gianluca; Vitelli, Riccardo [Department of Computer Science, Systems and Production, University of Rome Tor Vergata, Rome (Italy); Galperti, Critsian [Istituto di Fisica del Plasma, CNR, EURATOM-ENEA Association, Milan (Italy); Zarfati, Emanuele; Pucci, Daniele [Department Antonio Ruberti, University of Rome La Sapienza, Rome (Italy)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer We show that the MARTe is a candidate for ITER PSH. Black-Right-Pointing-Pointer We replace the old real-time feedback software using the MARTe framework. Black-Right-Pointing-Pointer We describe all the work done for the integration. - Abstract: Keeping in mind the necessities of a modern control system for fusion devices, such as modularity and a distributed architecture, an upgrade of the present FTU feedback control system was planned, envisaging also a possible reutilization in the proposed FAST experiment [1]. For standardization and efficiency purposes we decided to adopt a pre-existent ITER-relevant framework called MARTe [2], already used with success in other European Tokamak devices [3]. Following the developments shown in [4], in this paper we report on the structure of the new feedback system, and how it was integrated in the current control structure and pulse programming interface, and in the other MARTe systems already in FTU: RT-ODIN [5] and the ECRH and LH [6] satellite stations. The new feedback system has been installed in the FTU backup station (known as 'Feedback B'), which shares the input signals with the actual feedback system, in order to simplify the validation and debug of the new controller by testing it in parallel with the current one. Experimental results are then presented.

  5. Simulation of neoclassical tearing mode stabilization via minimum seeking method on ITER

    Energy Technology Data Exchange (ETDEWEB)

    Park, M. H.; Kim, K.; Na, D. H.; Byun, C. S.; Na, Y. S. [Seoul National Univ., Seoul (Korea, Republic of); Kim, M. [FNC Technology Co. Ltd, Yongin (Korea, Republic of)

    2016-10-15

    Neoclassical tearing modes (NTMs) are well known resistive magnetohydrodynamic (MHD) instabilities. These instabilities are sustained by a helically perturbed bootstrap current. NTMs produce magnetic islands in tokamak plasmas that can degrade confinement and lead to plasma disruption. Because of this, the stabilization of NTMs is one of the key issues for tokamaks that achieve high fusion performance such as ITER. Compensating for the lack of bootstrap current by an Electron Cyclotron Current Drive (ECCD) has been proved experimentally as an effective method to stabilize NTMs. In order to stabilize NTMs, it is important to reduce misalignment. So that even ECCD can destabilize the NTMs when misalignment is large. Feedback control method that does not fully require delicate and accurate real-time measurements and calculations, such as equilibrium reconstruction and EC ray-tracing, has also been proposed. One of the feedback control methods is minimum seeking method. This control method minimizes the island width by tuning the misalignment, assuming that the magnetic island width is a function of the misalignment. As a robust and simple method of controlling NTM, minimum 'island width growth rate' seeking control is purposed and compared with performance of minimum ' island width' seeking control. At the integrated numerical system, simulations of the NTM suppression are performed with two types of minimum seeking controllers; one is a FDM based minimum seeking controller and the other is a sinusoidal perturbation based minimum seeking method. The full suppression is achieved both types of controller. The controllers adjust poloidal angle of EC beam and reduce misalignment to zero. The sinusoidal perturbation based minimum seeking control need to modify the adaptive gain.

  6. Iterative group splitting algorithm for opportunistic scheduling systems

    KAUST Repository

    Nam, Haewoon

    2014-05-01

    An efficient feedback algorithm for opportunistic scheduling systems based on iterative group splitting is proposed in this paper. Similar to the opportunistic splitting algorithm, the proposed algorithm adjusts (or lowers) the feedback threshold during a guard period if no user sends a feedback. However, when a feedback collision occurs at any point of time, the proposed algorithm no longer updates the threshold but narrows down the user search space by dividing the users into multiple groups iteratively, whereas the opportunistic splitting algorithm keeps adjusting the threshold until a single user is found. Since the threshold is only updated when no user sends a feedback, it is shown that the proposed algorithm significantly alleviates the signaling overhead for the threshold distribution to the users by the scheduler. More importantly, the proposed algorithm requires a less number of mini-slots than the opportunistic splitting algorithm to make a user selection with a given level of scheduling outage probability or provides a higher ergodic capacity given a certain number of mini-slots. © 2013 IEEE.

  7. Feedback control of the neuromusculoskeletal system in a forward dynamics simulation of stair locomotion.

    Science.gov (United States)

    Selk Ghafari, A; Meghdari, A; Vossoughi, G

    2009-08-01

    The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional-integral-derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of pressure during locomotion. The parameters of the proposed controller were determined by employing the iterative feedback tuning approach to minimize tracking errors during forward dynamics simulation. Simultaneously, an inverse-dynamics-based optimization was employed to compute a set of desired musculotendon forces in the closed-loop simulation to resolve muscle redundancy. Quantitative comparisons of the simulation results with the experimental measurements and the reference muscles' activities illustrate the accuracy and efficiency of the proposed method during the stable ascending simulation.

  8. Rokkasho: Japanese site for ITER

    International Nuclear Information System (INIS)

    Ohtake, S.; Yamaguchi, V.; Matsuda, S.; Kishimoto, H.

    2003-01-01

    The Atomic Energy Commission of Japan authorized ITER as the core machine of the Third Phase Basic Program of Fusion Energy Development. After a series of discussions in the Atomic Energy Commission and the Council of Science and Technology Policy, Japanese Government concluded formally with the Cabinet Agreement on 31 May 2002 that Japan should participate in the ITER Project and offer the Rokkasho-Mura site for construction of ITER to the Negotiations among Canada (CA), the European Union (EU), Japan (JA), and the Russian Federation (RF). The JA site proposal is now under the international assessment in the framework of the ITER Negotiations. (author)

  9. ITER CTA newsletter. No. 13, October 2002

    International Nuclear Information System (INIS)

    2002-11-01

    This ITER CTA newsletter issue comprises concise information about an ITER related meeting concerning the joint implementation of ITER - the fifth ITER Negotiations Meeting - which was held in Toronto, Canada, 19-20 September, 2002, and information about assessment of the possible ITER site in Clarington, Ontario, Canada, which was the subject of the first official stage of the Joint Assessment of Specific Sites (JASS) for the ITER Project. This assessment was completed just before the Fifth ITER Negotiations Meeting

  10. ITER cooling systems

    International Nuclear Information System (INIS)

    Natalizio, A.; Hollies, R.E.; Sochaski, R.O.; Stubley, P.H.

    1992-06-01

    The ITER reference system uses low-temperature water for heat removal and high-temperature helium for bake-out. As these systems share common equipment, bake-out cannot be performed until the cooling system is drained and dried, and the reactor cannot be started until the helium has been purged from the cooling system. This study examines the feasibility of using a single high-temperature fluid to perform both heat removal and bake-out. The high temperature required for bake-out would also be in the range for power production. The study examines cost, operational benefits, and impact on reactor safety of two options: a high-pressure water system, and a low-pressure organic system. It was concluded that the cost savings and operational benefits are significant; there are no significant adverse safety impacts from operating either the water system or the organic system; and the capital costs of both systems are comparable

  11. Iterated crowdsourcing dilemma game

    Science.gov (United States)

    Oishi, Koji; Cebrian, Manuel; Abeliuk, Andres; Masuda, Naoki

    2014-02-01

    The Internet has enabled the emergence of collective problem solving, also known as crowdsourcing, as a viable option for solving complex tasks. However, the openness of crowdsourcing presents a challenge because solutions obtained by it can be sabotaged, stolen, and manipulated at a low cost for the attacker. We extend a previously proposed crowdsourcing dilemma game to an iterated game to address this question. We enumerate pure evolutionarily stable strategies within the class of so-called reactive strategies, i.e., those depending on the last action of the opponent. Among the 4096 possible reactive strategies, we find 16 strategies each of which is stable in some parameter regions. Repeated encounters of the players can improve social welfare when the damage inflicted by an attack and the cost of attack are both small. Under the current framework, repeated interactions do not really ameliorate the crowdsourcing dilemma in a majority of the parameter space.

  12. Applying principles of Design For Assembly to ITER maintenance operations

    International Nuclear Information System (INIS)

    Heemskerk, Cock; de Baar, Marco; Elzendoorn, Ben; Koning, Jarich; Verhoeven, Toon; Vreede, Fred de

    2009-01-01

    In ITER, maintenance operations in the vessel and in the Hot Cell will be largely done by Remote Handling (RH). Remotely performed maintenance actions tend to be more time-costly than actions performed by direct human access. With a human operator in the control loop and adequate situational feedback, a two-armed master slave manipulator system can mimic direct access with dexterous manipulation, tactile feedback and vision. But even then, turnaround times are still very high. Adapting the design for simplified maintenance operations can yield significant time savings. One of the methods known to produce a simpler, more robust design, which is also better suited for handling with robots, is Design For Assembly (DFA). This paper discusses whether and how the principles of DFA can be applied to simplify maintenance operations for ITER. While DFA is normally used with series-production and ITER is a unique product, it is possible to apply the principles of DFA to ITER maintenance operations. Furthermore, DFA's principles can be applied at different abstraction levels. Combining principles of DFA with Virtual Reality leads to new insights and provides additional value.

  13. ITER-FEAT - outline design report. Report by the ITER Director. ITER meeting, Tokyo, January 2000

    International Nuclear Information System (INIS)

    2001-01-01

    It is now possible to define the key elements of ITER-FEAT. This report provides the results, to date, of the joint work of the Special Working Group in the form of an Outline Design Report on the ITER-FEAT design which, subject to the views of ITER Council and of the Parties, will be the focus of further detailed design work and analysis in order to provide to the Parties a complete and fully integrated engineering design within the framework of the ITER EDA extension

  14. LCLS Undulator Tuning And Fiducialization

    International Nuclear Information System (INIS)

    Wolf, Zachary; Kaplounenko, Vsevolod; Levashov, Yury; Weidemann, Achim

    2007-01-01

    The LCLS project at SLAC requires 40 undulators: 33 in the beam line, 6 spares, and one reference undulator. A new facility was constructed at SLAC for tuning and fiducializing the undulators. The throughput of the facility must be approximately one undulator per week. The undulator tuning has been partially automated. Fiducialization techniques have been devised. The new facility, the tuning techniques, and the fiducialization techniques will be discussed

  15. Beam tuning and stabilization using beam phase measurements at GANIL

    International Nuclear Information System (INIS)

    Chabert, A.; Loyer, F.; Sauret, J.

    1984-06-01

    Owing to the great sensitivity of the beam phase to the various parameters, on line beam phase measurements proved to be a very efficient way of tuning and stabilizing the beam of the multi-accelerator complex. We recall the system which allows to obtain the different kinds of accurate measurements we need and describe the main applications: - tuning process (buncher and SSC's RF phase determination, setting of the required radial beam phase law in the SSC's); - stabilization of the beam by loops, the basic principle of which being to keep constant the beam central phase all along the machine by adjusting RF voltages or magnetic fields. Feedback loops are described and comparative results with and without feedback are given

  16. ITER CTA newsletter. No. 7

    International Nuclear Information System (INIS)

    2002-04-01

    This issue of ITER CTA newsletter contains information about the meeting of the ITER CTA project board, which took place in Moscow, Russian Federation on 22 April 2002 on the occasion of the Third Negotiators Meeting (N3), and about the meeting 'EU divertor celebration day' organized on 16 January 2002 at Plansee AG, Reutte, Austria

  17. Realtime tune measurements in slow-cycling accelerators

    International Nuclear Information System (INIS)

    Herrup, D.

    1997-01-01

    Measurement and control of the tunes, coupling, and chromaticities in storage rings is essential to efficient operation of these accelerators. Yet it has been very difficult to make reliable realtime measurements of these quantities. We have built and commissioned the microprocessor-based Generic Finite State Data Acquisition (GFSDA) system. GFSDA provides turn-by-turn data acquisition and analysis of accelerator signals in a way that can be easily related to accelerator operations. The microprocessor is capable of calculating FFTs and correlations in real time. Both the Fermilab Main Ring and Tevatron use open loop tune, chromaticity, and coupling control, and the GFSDA measurements can easily be used to improve the open loop tables. We can add realtime feedback control with simple extensions of the system. We have used this system to make tune measurements closely spaced in time over an entire Tevatron ramp cycle

  18. Plasma control concepts for ITER

    International Nuclear Information System (INIS)

    Lister, J.B.; Nieswand, C.

    1997-01-01

    This overview paper skims over a wide range of issues related to the control of ITER plasmas. Although operation of the ITER project will require extensive developmental work to achieve the degree of control required, there is no indication that any of the identified problems will present overwhelming difficulties compared with the operation of present tokamaks. However, the precision of control required and the degree of automation of the final ITER plasma control system will present a challenge which is somewhat greater than for present tokamaks. In order to operate ITER optimally, integrated use of a large amount of diagnostic information will be necessary, evaluated and interpreted automatically. This will challenge both the diagnostics themselves and their supporting interpretation codes. The intervening years will provide us with the opportunity to implement and evaluate most of the new features required for ITER on existing tokamaks, with the exception of the control of an ignited plasma. (author) 7 figs., 7 refs

  19. ITER EDA Newsletter. V. 3, no. 8

    International Nuclear Information System (INIS)

    1994-08-01

    This ITER EDA (Engineering Design Activities) Newsletter issue reports on the sixth ITER council meeting; introduces the newly appointed ITER director and reports on his address to the ITER council. The vacuum tank for the ITER model coil testing, installed at JAERI, Naka, Japan is also briefly described

  20. ITER interim design report package documents

    International Nuclear Information System (INIS)

    1996-01-01

    This publication contains the Excerpt from the ITER Council (IC-8), the ITER Interim Design Report, Cost Review and Safety Analysis, ITER Site Requirements and ITER Site Design Assumptions and the Excerpt from the ITER Council (IC-9). 8 figs, 2 tabs

  1. ITER ITA newsletter. No. 8, September 2003

    International Nuclear Information System (INIS)

    2003-10-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related activities including Robert Aymar's leaving ITER for CERN, ITER related issues at the IAEA General Conference and status and prospects of thermonuclear power and activity during the ITA on materials foe vessel and in-vessel components

  2. Operational status of the transverse multibunch feedback system at Diamond

    International Nuclear Information System (INIS)

    Uzun, I.; Abbott, M.; Heron, M.T.; Morgan, A.F.D.; Rehm, G.

    2012-01-01

    A transverse multibunch feedback (TMBF) system is in operation at Diamond Light Source to damp coupled-bunch instabilities up to 250 MHz in both the vertical and horizontal planes. It comprises an in-house designed and built analogue front end combined with a Libera Bunch-by-Bunch feedback processor and output stripline kickers. FPGA-based feedback electronics is used to implement several diagnostic features in addition to the basic feedback functionality. This paper reports on the current operational status of the TMBF system along with its characteristics. Also discussed are operational diagnostic functionalities including continuous measurement of the betatron tune and chromaticity. (authors)

  3. Magnetic Configuration Control of ITER Plasmas

    International Nuclear Information System (INIS)

    Albanese, R.; Artaserse, G.; Mattei, M.; Ambrosino, G.; Crisanti, F.; Tommasi, G. de; Fresa, R.; Portone, A.; Sartori, F.; Villone, F.

    2006-01-01

    The aim of this paper is to review the capability of the ITER Poloidal Field (PF) system of controlling the broad range of plasma configurations presently forecasted during ITER operation. The attention is focused on the axi-symmetric aspects of plasma magnetic configuration control since they pose the greatest challenges in terms of control power and they have the largest impact on machine capital cost. The paper is broadly divided in two main sections devoted, respectively, to open loop (feed-forward) and closed loop (feedback) control. In the first part of the study the PF system is assessed with respect to the initiation, ramp-up, sustained burn, ramp-down phases of the main plasma inductive scenario. The limiter-to-divertor configuration transition phase is considered in detail with the aim of assessing the PF capability to form an X-point at the lowest possible current and, therefore, to relax the thermal load on the limiter surfaces. Moreover, during the sustained burn it is important to control plasmas with a broad range of current density profiles. In the second part of the study the plasma vertical feedback control requirements are assessed in details, in particular for the high elongation configurations achievable during the early limiter-to-X point transition phase. Non-rigid plasma displacement models are used to assess the control system voltage and current requirements of different radial field control circuits obtained, for example, by connecting the outermost PF coils, some CS coils, coils sub-sections etc. At last, the main 3D effects of the vessel ports are modeled and their impact of vertical stabilization evaluated. (author)

  4. PID control with robust disturbance feedback control

    DEFF Research Database (Denmark)

    Kawai, Fukiko; Vinther, Kasper; Andersen, Palle

    2015-01-01

    Disturbance Feedback Control (DFC) is a technique, originally proposed by Fuji Electric, for augmenting existing control systems with an extra feedback for attenuation of disturbances and model errors. In this work, we analyze the robustness and performance of a PID-based control system with DFC...... and performance (if such gains exist). Finally, two different simulation case studies are evaluated and compared. Our numerical studies indicate that better performance can be achieved with the proposed method compared with a conservatively tuned PID controller and comparable performance can be achieved when...... compared with an H-infinity controller....

  5. Baseline Architecture of ITER Control System

    Science.gov (United States)

    Wallander, A.; Di Maio, F.; Journeaux, J.-Y.; Klotz, W.-D.; Makijarvi, P.; Yonekawa, I.

    2011-08-01

    The control system of ITER consists of thousands of computers processing hundreds of thousands of signals. The control system, being the primary tool for operating the machine, shall integrate, control and coordinate all these computers and signals and allow a limited number of staff to operate the machine from a central location with minimum human intervention. The primary functions of the ITER control system are plant control, supervision and coordination, both during experimental pulses and 24/7 continuous operation. The former can be split in three phases; preparation of the experiment by defining all parameters; executing the experiment including distributed feed-back control and finally collecting, archiving, analyzing and presenting all data produced by the experiment. We define the control system as a set of hardware and software components with well defined characteristics. The architecture addresses the organization of these components and their relationship to each other. We distinguish between physical and functional architecture, where the former defines the physical connections and the latter the data flow between components. In this paper, we identify the ITER control system based on the plant breakdown structure. Then, the control system is partitioned into a workable set of bounded subsystems. This partition considers at the same time the completeness and the integration of the subsystems. The components making up subsystems are identified and defined, a naming convention is introduced and the physical networks defined. Special attention is given to timing and real-time communication for distributed control. Finally we discuss baseline technologies for implementing the proposed architecture based on analysis, market surveys, prototyping and benchmarking carried out during the last year.

  6. Performance Analysis of Iterative Channel Estimation and Multiuser Detection in Multipath DS-CDMA Channels

    OpenAIRE

    Li, Husheng; Betz, Sharon M.; Poor, H. Vincent

    2006-01-01

    This paper examines the performance of decision feedback based iterative channel estimation and multiuser detection in channel coded aperiodic DS-CDMA systems operating over multipath fading channels. First, explicit expressions describing the performance of channel estimation and parallel interference cancellation based multiuser detection are developed. These results are then combined to characterize the evolution of the performance of a system that iterates among channel estimation, multiu...

  7. Robust Course Keeping Control of a Fully Submerged Hydrofoil Vessel without Velocity Measurement: An Iterative Learning Approach

    Directory of Open Access Journals (Sweden)

    Sheng Liu

    2017-01-01

    Full Text Available This paper proposes a novel robust output feedback control methodology for the course keeping control of a fully submerged hydrofoil vessel. Based on a sampled-data iterative learning strategy, an iterative learning observer is established for the estimation of system states and the generalized disturbances. With the state observer, a feedback linearized iterative sliding mode controller is designed for the stabilization of the lateral dynamics of the fully submerged hydrofoil vessel. The stability of the overall closed-loop system is analyzed based on Lyapunov stability theory. Comparative simulation results verify the effectiveness of the proposed control scheme and show the dominance of the disturbance rejection performance.

  8. The ITER cryostat

    International Nuclear Information System (INIS)

    Bourque, R.F.; Wykes, M.E.P.

    1995-01-01

    The ITER cryostat is the vacuum chamber containing the tokamak reactor. Its functions are (1) to provide a high vacuum environment to limit thermal loads to the superconducting magnet system by gas conduction and convection; (2) to be part of the second radioactivity confinement boundary; and (3) provide passive removal of decay heat for beyond design basis accidents. A separate thermal shield along the inside wall limits thermal radiation to the coils. An external concrete shield provides radiological protection. The cryostat consists of a cylindrical section bolted to torispherical heads at top and bottom. The vessel is made up of two concentric walls connected by horizontal and vertical ribs. The space between the walls can be filled with helium gas at slightly above one atmosphere for thermal coupling of the two walls, to block inbound air microleaks, and for leak detection. The cryostat has many penetrations, some as large as four meters diameter, providing various types of access from the outside to the tokamak. These include heat transport system cooling pipes, cryogenic feeds, auxiliary heating, diagnostics, and blanket and divertor removal ports. Large bellows are used between the cryostat and the tokamak to accommodate differential thermal expansion

  9. ITER plasma facing components

    International Nuclear Information System (INIS)

    Kuroda, T.; Vieider, G.; Akiba, M.

    1991-01-01

    This document summarizes results of the Conceptual Design Activities (1988-1990) for the International Thermonuclear Experimental Reactor (ITER) project, namely those that pertain to the plasma facing components of the reactor vessel, of which the main components are the first wall and the divertor plates. After an introduction and an executive summary, the principal functions of the plasma-facing components are delineated, i.e., (i) define the low-impurity region within which the plasma is produced, (ii) absorb the electromagnetic radiation and charged-particle flux from the plasma, and (iii) protect the blanket/shield components from the plasma. A list of critical design issues for the divertor plates and the first wall is given, followed by discussions of the divertor plate design (including the issues of material selection, erosion lifetime, design concepts, thermal and mechanical analysis, operating limits and overall lifetime, tritium inventory, baking and conditioning, safety analysis, manufacture and testing, and advanced divertor concepts) and the first wall design (armor material and design, erosion lifetime, overall design concepts, thermal and mechanical analysis, lifetime and operating limits, tritium inventory, baking and conditioning, safety analysis, manufacture and testing, an alternative first wall design, and the limiters used instead of the divertor plates during start-up). Refs, figs and tabs

  10. ITER cooling system

    International Nuclear Information System (INIS)

    Kveton, O.K.

    1990-11-01

    The present specification of the ITER cooling system does not permit its operation with water above 150 C. However, the first wall needs to be heated to higher temperatures during conditioning at 250 C and bake-out at 350 C. In order to use the cooling water for these operations the cooling system would have to operate during conditioning at 37 Bar and during bake-out at 164 Bar. This is undesirable from the safety analysis point of view, and alternative heating methods are to be found. This review suggests that superheated steam or gas heating can be used for both baking and conditioning. The blanket design must consider the use of dual heat transfer media, allowing for change from one to another in both directions. Transfer from water to gas or steam is the most intricate and risky part of the entire heating process. Superheated steam conditioning appears unfavorable. The use of inert gas is recommended, although alternative heating fluids such as organic coolant should be investigated

  11. ITER EDA newsletter. V. 9, no. 2

    International Nuclear Information System (INIS)

    2000-02-01

    This ITER EDA Newsletter reports on the seventh ITER technical meeting on safety and environment and contains the executive summary of the eleventh ITER scrape-off layer and divertor physics expert group meeting. Individual abstracts have been prepared

  12. ITER EDA newsletter. V. 7, no. 6

    International Nuclear Information System (INIS)

    1998-06-01

    This newsletter contains the articles: 'ITER representation at the 11th Pacific Basin Nuclear Conference', 'Summary of discussion points and further deliberations in the special committee on the ITER project in the Atomic Energy Commission', and 'ITER radio frequency systems'

  13. ITER safety challenges and opportunities

    International Nuclear Information System (INIS)

    Piet, S.J.

    1992-01-01

    This paper reports on results of the Conceptual Design Activity (CDA) for the International Thermonuclear Experimental Reactor (ITER) suggest challenges and opportunities. ITER is capable of meeting anticipated regulatory dose limits, but proof is difficult because of large radioactive inventories needing stringent radioactivity confinement. Much research and development (R ampersand D) and design analysis is needed to establish that ITER meets regulatory requirements. There is a further oportunity to do more to prove more of fusion's potential safety and environmental advantages and maximize the amount of ITER technology on the path toward fusion power plants. To fulfill these tasks, three programmatic challenges and three technical challenges must be overcome. The first step is to fund a comprehensive safety and environmental ITER R ampersand D plan. Second is to strengthen safety and environment work and personnel in the international team. Third is to establish an external consultant group to advise the ITER Joint Team on designing ITER to meet safety requirements for siting by any of the Parties. The first of three key technical challenges is plasma engineering - burn control, plasma shutdown, disruptions, tritium burn fraction, and steady state operation. The second is the divertor, including tritium inventory, activation hazards, chemical reactions, and coolant disturbances. The third technical challenge is optimization of design requirements considering safety risk, technical risk, and cost

  14. ITER EDA Newsletter. V. 10, no. 7

    International Nuclear Information System (INIS)

    2001-07-01

    This ITER EDA Newsletter presents an overview of meetings held at IAEA Headquarters in Vienna during the week 16-20 July 2001 related to the successful completion of the ITER Engineering Design Activities (EDA). Among them were the final meeting of the ITER Council, the closing ceremony to commemorate the EDA completion, the final meeting of the ITER Management Advisory Committee, a briefing of issues related to ITER developments, and discussions on the possible joint implementation of ITER

  15. Neuromechanical tuning of nonlinear postural control dynamics

    Science.gov (United States)

    Ting, Lena H.; van Antwerp, Keith W.; Scrivens, Jevin E.; McKay, J. Lucas; Welch, Torrence D. J.; Bingham, Jeffrey T.; DeWeerth, Stephen P.

    2009-06-01

    Postural control may be an ideal physiological motor task for elucidating general questions about the organization, diversity, flexibility, and variability of biological motor behaviors using nonlinear dynamical analysis techniques. Rather than presenting "problems" to the nervous system, the redundancy of biological systems and variability in their behaviors may actually be exploited to allow for the flexible achievement of multiple and concurrent task-level goals associated with movement. Such variability may reflect the constant "tuning" of neuromechanical elements and their interactions for movement control. The problem faced by researchers is that there is no one-to-one mapping between the task goal and the coordination of the underlying elements. We review recent and ongoing research in postural control with the goal of identifying common mechanisms underlying variability in postural control, coordination of multiple postural strategies, and transitions between them. We present a delayed-feedback model used to characterize the variability observed in muscle coordination patterns during postural responses to perturbation. We emphasize the significance of delays in physiological postural systems, requiring the modulation and coordination of both the instantaneous, "passive" response to perturbations as well as the delayed, "active" responses to perturbations. The challenge for future research lies in understanding the mechanisms and principles underlying neuromechanical tuning of and transitions between the diversity of postural behaviors. Here we describe some of our recent and ongoing studies aimed at understanding variability in postural control using physical robotic systems, human experiments, dimensional analysis, and computational models that could be enhanced from a nonlinear dynamics approach.

  16. Iterative optimization in inverse problems

    CERN Document Server

    Byrne, Charles L

    2014-01-01

    Iterative Optimization in Inverse Problems brings together a number of important iterative algorithms for medical imaging, optimization, and statistical estimation. It incorporates recent work that has not appeared in other books and draws on the author's considerable research in the field, including his recently developed class of SUMMA algorithms. Related to sequential unconstrained minimization methods, the SUMMA class includes a wide range of iterative algorithms well known to researchers in various areas, such as statistics and image processing. Organizing the topics from general to more

  17. Remote maintenance development for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Eisuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Shibanuma, Kiyoshi

    1998-04-01

    This paper describes the overall ITER remote maintenance design concept developed mainly for in-vessel components such as diverters and blankets, and outlines the ITER R and D program to develop remote handling equipment and radiation hard components. Reactor structures inside the ITER cryostat must be maintained remotely due to DT operation, making remote handling technology basic to reactor design. The overall maintenance scenario and design concepts have been developed, and maintenance design feasibility, including fabrication and testing of full-scale in-vessel remote maintenance handling equipment and tool, is being verified. (author)

  18. Iterative nonlinear unfolding code: TWOGO

    International Nuclear Information System (INIS)

    Hajnal, F.

    1981-03-01

    a new iterative unfolding code, TWOGO, was developed to analyze Bonner sphere neutron measurements. The code includes two different unfolding schemes which alternate on successive iterations. The iterative process can be terminated either when the ratio of the coefficient of variations in terms of the measured and calculated responses is unity, or when the percentage difference between the measured and evaluated sphere responses is less than the average measurement error. The code was extensively tested with various known spectra and real multisphere neutron measurements which were performed inside the containments of pressurized water reactors

  19. ITER containment structures

    International Nuclear Information System (INIS)

    Sadakov, S.; Fauser, F.; Nelson, B.

    1991-01-01

    This document describes the results and recommendations of the Containment Structures Design Unit (CSDU) on the containment structures for ITER, made in the context of the Conceptual Design Phase. The document describes the following subsystems: (1) the primary vacuum vessel (VV), (2) the attaching locks (AL) of the invessel components, (3) the plasma passive and active stabilizers, (4) the cryostat vessel, and (5) the machine gravity supports. Although for most components reference designs were selected, for some of these alternative design options were described, because unresolved problems necessitate further research and development. Conclusions and future needs are summarized for each of the above subsystems: (1) a reference VV design was selected, while most critical VV future needs are the feasibility studies of manufacturing, assembly, and the repair/disassembly/reassembly by remote handling. Alternative, thin-wall options appear attractive and should be studied further during the Engineering Design Activities; (2) no reference design solution was selected for the AL system, as AL design requirements are extremely difficult and internally contradictory, while there is no existing tokamak precedent, but instead, five different approaches will be further researched early in the Engineering Design Phase; (3) significant progress is reported on passive loops, for which the ''twin-loops'' concept is ready to be advanced into the Engineering Design Phase, and on active coils, where a new coil positioning prevents interference with the blanket removal paths, and the current joints are located in a secondary vacuum or in the atmosphere of the reactor hall, repairable by remote handling; (4) a full metallic welded cryostat design with increased toroidal resistance was chosen, but with a design based on concrete with a thin inner metallic liner as a back-up in case detailed nuclear shielding requirements would force the cryostat to act as biological shield; (5) out

  20. Cooperation between CERN and ITER

    CERN Multimedia

    2008-01-01

    CERN and the International Fusion Organisation ITER have just signed a first cooperation agreeement. Kaname Ikeda, the Director-General of the International Fusion Energy Organisation (ITER) (on the right) and Robert Aymar, Director-General of CERN, signing the agreement.The Director-General of the International Fusion Energy Organization, Mr Kaname Ikeda, and CERN Director-General, Robert Aymar, signed a cooperation agreement at a meeting on the Meyrin site on Thursday 6 March. One of the main purposes of this agreement is for CERN to give ITER the benefit of its experience in the field of technology as well as in administrative domains such as finance, procurement, human resources and informatics through the provision of consultancy services. Currently in its start-up phase at its Cadarache site, 70 km from Marseilles (France), ITER will focus its research on the scientific and technical feasibility of using fusion energy as a fu...

  1. Rollout sampling approximate policy iteration

    NARCIS (Netherlands)

    Dimitrakakis, C.; Lagoudakis, M.G.

    2008-01-01

    Several researchers have recently investigated the connection between reinforcement learning and classification. We are motivated by proposals of approximate policy iteration schemes without value functions, which focus on policy representation using classifiers and address policy learning as a

  2. ITER Conceptual design: Interim report

    International Nuclear Information System (INIS)

    1990-01-01

    This interim report describes the results of the International Thermonuclear Experimental Reactor (ITER) Conceptual Design Activities after the first year of design following the selection of the ITER concept in the autumn of 1988. Using the concept definition as the basis for conceptual design, the Design Phase has been underway since October 1988, and will be completed at the end of 1990, at which time a final report will be issued. This interim report includes an executive summary of ITER activities, a description of the ITER device and facility, an operation and research program summary, and a description of the physics and engineering design bases. Included are preliminary cost estimates and schedule for completion of the project

  3. ITER leader to head CERN

    CERN Document Server

    Feder, Toni

    2003-01-01

    After successfully chairing an external review committee for CERN last year, Robert Aymar will leave ITER to become director general of the European particle physics laboratory rom 2004. Before ITER he also successfully managed the startup or Tore Supra. He will attempt to ensure that the LHC begins operating in 2007 - two years late - and is paid for by 2010 and will also start the planning for life after the LHC (1 page)

  4. The ITER reduced cost design

    International Nuclear Information System (INIS)

    Aymar, R.

    2000-01-01

    Six years of joint work under the international thermonuclear experimental reactor (ITER) EDA agreement yielded a mature design for ITER which met the objectives set for it (ITER final design report (FDR)), together with a corpus of scientific and technological data, large/full scale models or prototypes of key components/systems and progress in understanding which both validated the specific design and are generally applicable to a next step, reactor-oriented tokamak on the road to the development of fusion as an energy source. In response to requests from the parties to explore the scope for addressing ITER's programmatic objective at reduced cost, the study of options for cost reduction has been the main feature of ITER work since summer 1998, using the advances in physics and technology databases, understandings, and tools arising out of the ITER collaboration to date. A joint concept improvement task force drawn from the joint central team and home teams has overseen and co-ordinated studies of the key issues in physics and technology which control the possibility of reducing the overall investment and simultaneously achieving the required objectives. The aim of this task force is to achieve common understandings of these issues and their consequences so as to inform and to influence the best cost-benefit choice, which will attract consensus between the ITER partners. A report to be submitted to the parties by the end of 1999 will present key elements of a specific design of minimum capital investment, with a target cost saving of about 50% the cost of the ITER FDR design, and a restricted number of design variants. Outline conclusions from the work of the task force are presented in terms of physics, operations, and design of the main tokamak systems. Possible implications for the way forward are discussed

  5. ITER diagnostic system: Vacuum interface

    International Nuclear Information System (INIS)

    Patel, K.M.; Udintsev, V.S.; Hughes, S.; Walker, C.I.; Andrew, P.; Barnsley, R.; Bertalot, L.; Drevon, J.M.; Encheva, A.; Kashchuk, Y.; Maquet, Ph.; Pearce, R.; Taylor, N.; Vayakis, G.; Walsh, M.J.

    2013-01-01

    Diagnostics play an essential role for the successful operation of the ITER tokamak. They provide the means to observe control and to measure plasma during the operation of ITER tokamak. The components of the diagnostic system in the ITER tokamak will be installed in the vacuum vessel, in the cryostat, in the upper, equatorial and divertor ports, in the divertor cassettes and racks, as well as in various buildings. Diagnostic components that are placed in a high radiation environment are expected to operate for the life of ITER. There are approx. 45 diagnostic systems located on ITER. Some diagnostics incorporate direct or independently pumped extensions to maintain their necessary vacuum conditions. They require a base pressure less than 10 −7 Pa, irrespective of plasma operation, and a leak rate of less than 10 −10 Pa m 3 s −1 . In all the cases it is essential to maintain the ITER closed fuel cycle. These directly coupled diagnostic systems are an integral part of the ITER vacuum containment and are therefore subject to the same design requirements for tritium and active gas confinement, for all normal and accidental conditions. All the diagnostics, whether or not pumped, incorporate penetration of the vacuum boundary (i.e. window assembly, vacuum feedthrough etc.) and demountable joints. Monitored guard volumes are provided for all elements of the vacuum boundary that are judged to be vulnerable by virtue of their construction, material, load specification etc. Standard arrangements are made for their construction and for the monitoring, evacuating and leak testing of these volumes. Diagnostic systems are incorporated at more than 20 ports on ITER. This paper will describe typical and particular arrangements of pumped diagnostic and monitored guard volume. The status of the diagnostic vacuum systems, which are at the start of their detailed design, will be outlined and the specific features of the vacuum systems in ports and extensions will be described

  6. The ITER remote maintenance system

    International Nuclear Information System (INIS)

    Tesini, A.

    2007-01-01

    Full text of publication follows: ITER is a joint international research and development project that aims to demonstrate the scientific and technological feasibility of fusion power. As soon as the plasma operation begins using tritium, the replacement of the vacuum vessel internal components will need to be done with remote handling techniques. To accomplish these operations ITER has equipped itself with a Remote Maintenance System; this includes the Remote Handling equipment set and the Hot Cell facility. Both need to work in a cooperative way, with the aim of minimizing the machine shutdown periods and to maximize the machine availability. The ITER Remote Handling equipment set is required to be available, robust, reliable and retrievable. The machine components, to be remotely handle-able, are required to be designed simply so as to ease their maintenance. The baseline ITER Remote Handling equipment is described. The ITER Hot Cell Facility is required to provide a controlled and shielded area for the execution of repair operations (carried out using dedicated remote handling equipment) on those activated components which need to be returned to service, inside the vacuum vessel. The Hot Cell provides also the equipment and space for the processing and temporary storage of the operational and decommissioning rad-waste. A conceptual ITER Hot Cell Facility is described. (authors)

  7. ITER concept definition. V.1

    International Nuclear Information System (INIS)

    1989-01-01

    Under the auspices of the International Atomic Energy Agency (IAEA), an agreement among the four parties representing the world's major fusion programs resulted in a program for conceptual design of the next logical step in the fusion program, the International Thermonuclear Experimental Reactor (ITER). The definition phase, which ended in November, 1989, is summarized in two reports: a brief summary is contained in the ITER Definition Phase Report (IAEA/ITER/DS/2); the extended technical summary and technical details of ITER are contained in this two-volume report. The first volume of this report contains the Introduction and Summary, and the remainder will appear in Volume II. In the Conceptual Design Activities phase, ITER has been defined as being a tokamak device. The basic performance parameters of ITER are given in Volume I of this report. In addition, the rationale for selection of this concept, the performance flexibility, technical issues, operations, safety, reliability, cost, and research and development needed to proceed with the design are discussed. Figs and tabs

  8. The ITER remote maintenance system

    International Nuclear Information System (INIS)

    Tesini, A.; Palmer, J.

    2007-01-01

    ITER is a joint international research and development project that aims to demonstrate the scientific and technological feasibility of fusion power. As soon as the plasma operation begins using tritium, the replacement of the vacuum vessel internal components will need to be done with remote handling techniques. To accomplish these operations ITER has equipped itself with a Remote Maintenance System; this includes the Remote Handling equipment set and the Hot Cell facility. Both need to work in a cooperative way, with the aim of minimizing the machine shutdown periods and to maximize the machine availability. The ITER Remote Handling equipment set is required to be available, robust, reliable and retrievable. The machine components, to be remotely handle-able, are required to be designed simply so as to ease their maintenance. The baseline ITER Remote Handling equipment is described. The ITER Hot Cell Facility is required to provide a controlled and shielded area for the execution of repair operations (carried out using dedicated remote handling equipment) on those activated components which need to be returned to service, inside the vacuum vessel. The Hot Cell provides also the equipment and space for the processing and temporary storage of the operational and decommissioning radwaste. A conceptual ITER Hot Cell Facility is described. (orig.)

  9. Ideal and conventional feedback systems for RWM suppression

    Energy Technology Data Exchange (ETDEWEB)

    Pustovitov, V.D.

    2002-01-01

    Feedback suppression of resistive wall modes (RWM) is studied analytically using a model based on a standard cylindrical approximation. Two feedback systems are compared: 'ideal', creating only the field necessary for RMW suppression, and 'conventional', like that used in the DIII-D tokamak and considered as a candidate for ITER. The widespread opinion that the feedback with poloidal sensors is better than that with radial sensors is discussed. It is shown that the 'conventional' feedback with radial sensors can be effective only in a limited range, while using the input signal from internal poloidal sensors allows easy fulfilment of the stability criterion. This is a property of the 'conventional' feedback, but the 'ideal' feedback would stabilise RWM in both cases. (author)

  10. ITER Central Solenoid Module Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Smith, John [General Atomics, San Diego, CA (United States)

    2016-09-23

    The fabrication of the modules for the ITER Central Solenoid (CS) has started in a dedicated production facility located in Poway, California, USA. The necessary tools have been designed, built, installed, and tested in the facility to enable the start of production. The current schedule has first module fabrication completed in 2017, followed by testing and subsequent shipment to ITER. The Central Solenoid is a key component of the ITER tokamak providing the inductive voltage to initiate and sustain the plasma current and to position and shape the plasma. The design of the CS has been a collaborative effort between the US ITER Project Office (US ITER), the international ITER Organization (IO) and General Atomics (GA). GA’s responsibility includes: completing the fabrication design, developing and qualifying the fabrication processes and tools, and then completing the fabrication of the seven 110 tonne CS modules. The modules will be shipped separately to the ITER site, and then stacked and aligned in the Assembly Hall prior to insertion in the core of the ITER tokamak. A dedicated facility in Poway, California, USA has been established by GA to complete the fabrication of the seven modules. Infrastructure improvements included thick reinforced concrete floors, a diesel generator for backup power, along with, cranes for moving the tooling within the facility. The fabrication process for a single module requires approximately 22 months followed by five months of testing, which includes preliminary electrical testing followed by high current (48.5 kA) tests at 4.7K. The production of the seven modules is completed in a parallel fashion through ten process stations. The process stations have been designed and built with most stations having completed testing and qualification for carrying out the required fabrication processes. The final qualification step for each process station is achieved by the successful production of a prototype coil. Fabrication of the first

  11. Skriftlig feedback i engelskundervisningen

    DEFF Research Database (Denmark)

    Kjærgaard, Hanne Wacher

    2017-01-01

    The article describes useful feedback strategies in language teaching and describes the feedback practices of lower-seconday teachers in Denmark. The article is aimed at language teahcers in secondary schools.......The article describes useful feedback strategies in language teaching and describes the feedback practices of lower-seconday teachers in Denmark. The article is aimed at language teahcers in secondary schools....

  12. Student Engagement with Feedback

    Science.gov (United States)

    Scott, Jon; Shields, Cathy; Gardner, James; Hancock, Alysoun; Nutt, Alex

    2011-01-01

    This report considers Biological Sciences students' perceptions of feedback, compared with those of the University as a whole, this includes what forms of feedback were considered most useful and how feedback used. Compared with data from previous studies, Biological Sciences students gave much greater recognition to oral feedback, placing it on a…

  13. Evaluating performance of MARTe as a real-time framework for feed-back control system at tokamak device

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Sangwon; Lee, Woongryol; Lee, Taegu; Park, Mikyung; Lee, Sangil [National Fusion Research Institute (NFRI), Gwahangno 169-148, Yuseong-Gu, Daejeon 305-806 (Korea, Republic of); Neto, André C. [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, P-1049-001 Lisboa (Portugal); Wallander, Anders [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Kim, Young-Kuk, E-mail: ykim@cnu.ac.kr [Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2013-10-15

    Highlights: •We measured the performance of MARTe by measuring response time and jitter. •We compared the performance of application with and without MARTe. •We compared the performance of MARTe application on different O/Ss. -- Abstract: The Korea Super conducting Tokamak Advanced Research (KSTAR) is performing the task of “Demonstration and Evaluation of ITER CODAC Technologies at KSTAR” whose objective is the evaluation of real-time technologies for decision making on real-time operating systems (RTOS), real-time frameworks and 10 GbE networks. In this task, the Multi-threaded Application Real-Time executor (MARTe) has been evaluated as a real-time framework for real-time feedback control system. The performance of MARTe has been verified by measuring response time and jitter in a path of feedback control from an analog input of a monitoring system to an analog output of an actuator system. In addition, the evaluation has been performed in terms of applicability of MARTe and its performance depending on types of operating system and tuning of CPU affinity and priority. This paper describes the overview of MARTe as a real-time framework, the results of evaluation performance and its implementation.

  14. Evaluating performance of MARTe as a real-time framework for feed-back control system at tokamak device

    International Nuclear Information System (INIS)

    Yun, Sangwon; Lee, Woongryol; Lee, Taegu; Park, Mikyung; Lee, Sangil; Neto, André C.; Wallander, Anders; Kim, Young-Kuk

    2013-01-01

    Highlights: •We measured the performance of MARTe by measuring response time and jitter. •We compared the performance of application with and without MARTe. •We compared the performance of MARTe application on different O/Ss. -- Abstract: The Korea Super conducting Tokamak Advanced Research (KSTAR) is performing the task of “Demonstration and Evaluation of ITER CODAC Technologies at KSTAR” whose objective is the evaluation of real-time technologies for decision making on real-time operating systems (RTOS), real-time frameworks and 10 GbE networks. In this task, the Multi-threaded Application Real-Time executor (MARTe) has been evaluated as a real-time framework for real-time feedback control system. The performance of MARTe has been verified by measuring response time and jitter in a path of feedback control from an analog input of a monitoring system to an analog output of an actuator system. In addition, the evaluation has been performed in terms of applicability of MARTe and its performance depending on types of operating system and tuning of CPU affinity and priority. This paper describes the overview of MARTe as a real-time framework, the results of evaluation performance and its implementation

  15. Operation of the PEP transverse beam feedback

    International Nuclear Information System (INIS)

    Olson, C.W.; Paterson, J.M.; Pellegrin, J.L.; Rees, J.R.

    1981-02-01

    The PEP Storage Ring has been equipped with a wide band beam feedback system capable of damping the vertical and horizontal motion of six bunches. The oscillation detection is done at a symmetry point on the Storage Ring and feedback is applied at the same location one orbital period later. The signal is synchronously gated and the system appears as twelve independent feedback loops, operating on the two coordinates of each of the six bunches. Two beam deflection electrodes are driven each by a low-Q push-pull amplifier which is tuned at the 72nd harmonic of the revolution frequency and suppressed-carrier modulation is generated by a sequence of the detected bunch oscillations. The design parameters are reviewed as well as the salient features of the hardware, and the impact of this system on the machine operation is evaluated in the light of experimental results

  16. Oracle SQL Tuning pocket Reference

    CERN Document Server

    Gurry, Mark

    2002-01-01

    One of the most important challenges faced by Oracle database administrators and Oracle developers is the need to tune SQL statements so that they execute efficiently. Poorly tuned SQL statements are one of the leading causes of substandard database performance and poor response time. SQL statements that perform poorly result in frustration for users, and can even prevent a company from serving its customers in a timely manner

  17. ITER EDA newsletter. V. 5, no. 9

    International Nuclear Information System (INIS)

    1996-09-01

    This issue of the Newsletter on the Engineering Design Activities (EDA) for the ITER project contains an overview of one of the seven large ITER Research and Development Projects identified by the ITER Director, namely the Vacuum Vessel Sector, as well as an account of computer animation created for ITER

  18. ITER EDA newsletter. V. 4, no. 9

    International Nuclear Information System (INIS)

    1995-09-01

    This issue of the ITER EDA (Engineering Design Activities) Newsletter contains reports on the first meeting of the ITER Test Blanket Working Group held 19-21 July 1995 at the ITER Garching Joint Work Site, and on the second workshop of the ITER Expert Group on Confinement and Transport

  19. ITER ITA newsletter. No. 22, May 2005

    International Nuclear Information System (INIS)

    2005-06-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about Japanese Participant Team's recent activities in the ITER Transitional Arrangements(ITA) phase and ITER related meeting the Fourth IAEA Technical Meeting (IAEA-TM) on Negative Ion Based Neutral Beam Injectors which was held in Padova, Italy from 9-11 May 2005

  20. ITER EDA newsletter. V. 10, no. 6

    International Nuclear Information System (INIS)

    2001-06-01

    This ITER EDA Newsletter issue includes information about the ITER Management Advisory Committee Meeting held in Vienna on 16 July 2001 and also a summary of the ninth ITER Technical Meeting on safety and environment held at the ITER Garching Joint Work site, 8 to 10 May, 2001

  1. ITER EDA Newsletter. V. 4, no. 5

    International Nuclear Information System (INIS)

    1995-05-01

    This issue of the ITER EDA (Engineering Design Activities) Newsletter contains comments on the ITER project by the Permanent Representative of the Russian Federation to the International Organizations in Vienna; a report on the ITER Magnet Technical Meeting held at the Joint Work Site at Naka, Japan, April 19-21, 1995; and a contribution entitled ''ITER spouses cross the cultures''

  2. ITER EDA newsletter. V. 8, no. 9

    International Nuclear Information System (INIS)

    1999-09-01

    This edition of the ITER EDA Newsletter contains a contribution by the ITER Director, R. Aymar, on the subject of developments in ITER Physics R and D report on the completion of the ITER central solenoid model coils installation by H. Tsuji, Head fo the Superconducting Magnet Laboratory at JAERI in Naka, Japan. Individual abstracts are prepared for each of the two articles

  3. ITER EDA newsletter. V. 7, no. 1

    International Nuclear Information System (INIS)

    1998-01-01

    This issue of the ITER Newsletter contains a summary report on the Thirteenth meeting of the ITER Management Advisory Committee (MAC), a report on ITER at the International Conference on Fusion Reactor Materials and a report of a Russian scientist working at ITER Garching JWS

  4. ITER ITA newsletter. No. 5, June 2003

    International Nuclear Information System (INIS)

    2003-08-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related activities, one of them retirement of Dr. Michel Huguet, deputy director of the ITER central team and the Head of Naka joint work site and another about 10.5 years of his activities at this site

  5. ITER EDA Newsletter. V.3, no.3

    International Nuclear Information System (INIS)

    1994-03-01

    This ITER EDA Newsletter issue contains reports on (i) the completion of the ITER EDA Protocol 1, (ii) the signing of ITER EDA Protocol 2, (iii) a technical meeting on pumping and fuelling and (iv) a technical meeting on the ITER Tritium Plant

  6. ITER EDA newsletter. V. 8, no. 12

    International Nuclear Information System (INIS)

    1999-12-01

    This ITER EDA Newsletter reports about the ITER Management Advisory Committee Meeting in Naka, the ITER Technical Advisory Committee Meeting in Naka and the meeting of the ITER SWG-P2 in Vienna. A separate abstract is prepared for each meeting

  7. ITER safety challenges and opportunities

    International Nuclear Information System (INIS)

    Piet, S.J.

    1991-01-01

    Results of the Conceptual Design Activity (CDA) for the International Thermonuclear Experimental Reactor (ITER) suggest challenges and opportunities. ''ITER is capable of meeting anticipated regulatory dose limits,'' but proof is difficult because of large radioactive inventories needing stringent radioactivity confinement. We need much research and development (R ampersand D) and design analysis to establish that ITER meets regulatory requirements. We have a further opportunity to do more to prove more of fusion's potential safety and environmental advantages and maximize the amount of ITER technology on the path toward fusion power plants. To fulfill these tasks, we need to overcome three programmatic challenges and three technical challenges. The first programmatic challenge is to fund a comprehensive safety and environmental ITER R ampersand D plan. Second is to strengthen safety and environment work and personnel in the international team. Third is to establish an external consultant group to advise the ITER Joint Team on designing ITER to meet safety requirements for siting by any of the Parties. The first of the three key technical challenges is plasma engineering -- burn control, plasma shutdown, disruptions, tritium burn fraction, and steady state operation. The second is the divertor, including tritium inventory, activation hazards, chemical reactions, and coolant disturbances. The third technical challenge is optimization of design requirements considering safety risk, technical risk, and cost. Some design requirements are now too strict; some are too lax. Fuel cycle design requirements are presently too strict, mandating inappropriate T separation from H and D. Heat sink requirements are presently too lax; they should be strengthened to ensure that maximum loss of coolant accident temperatures drop

  8. Fusion Power measurement at ITER

    International Nuclear Information System (INIS)

    Bertalot, L.; Barnsley, R.; Krasilnikov, V.; Stott, P.; Suarez, A.; Vayakis, G.; Walsh, M.

    2015-01-01

    Nuclear fusion research aims to provide energy for the future in a sustainable way and the ITER project scope is to demonstrate the feasibility of nuclear fusion energy. ITER is a nuclear experimental reactor based on a large scale fusion plasma (tokamak type) device generating Deuterium - Tritium (DT) fusion reactions with emission of 14 MeV neutrons producing up to 700 MW fusion power. The measurement of fusion power, i.e. total neutron emissivity, will play an important role for achieving ITER goals, in particular the fusion gain factor Q related to the reactor performance. Particular attention is given also to the development of the neutron calibration strategy whose main scope is to achieve the required accuracy of 10% for the measurement of fusion power. Neutron Flux Monitors located in diagnostic ports and inside the vacuum vessel will measure ITER total neutron emissivity, expected to range from 1014 n/s in Deuterium - Deuterium (DD) plasmas up to almost 10 21 n/s in DT plasmas. The neutron detection systems as well all other ITER diagnostics have to withstand high nuclear radiation and electromagnetic fields as well ultrahigh vacuum and thermal loads. (authors)

  9. ITER safety and licensing update

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Neill, E-mail: neill.taylor@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Ciattaglia, Sergio; Cortes, Pierre; Iseli, Markus; Rosanvallon, Sandrine; Topilski, Leonid [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer The ITER preliminary safety report has been submitted to the French nuclear regulator. Black-Right-Pointing-Pointer Safety analyses have shown how the key safety functions will be achieved. Black-Right-Pointing-Pointer The design contains multiple provisions for the confinement of radioactive material. Black-Right-Pointing-Pointer Analyses have addressed external hazards (e.g. earthquake) and loss of all power. - Abstract: Safety files were submitted by the ITER Organization to the French nuclear safety authorities in March 2010 as a part of the licensing process. These included the preliminary safety report (RPrS) which presents the extensive safety analyses performed for ITER. The report has been the subject of examination by the authorities and their advisors, and discussions with them have been held on many topics. In the light of this process, this paper discusses some of the topics that remain prominent in the safety analysis of ITER. In particular, the provision of the two safety functions, confinement of radioactive material and limitation of exposure to radiation, is explained and some of the potential challenges to them are identified. Amongst these are the risks of fire and explosion, and external events such as earthquake and loss of all electric power. Provisions in the ITER design, together with the characteristics of fusion, ensure that a very good safety performance will be achieved.

  10. Iterative near-term ecological forecasting: Needs, opportunities, and challenges.

    Science.gov (United States)

    Dietze, Michael C; Fox, Andrew; Beck-Johnson, Lindsay M; Betancourt, Julio L; Hooten, Mevin B; Jarnevich, Catherine S; Keitt, Timothy H; Kenney, Melissa A; Laney, Christine M; Larsen, Laurel G; Loescher, Henry W; Lunch, Claire K; Pijanowski, Bryan C; Randerson, James T; Read, Emily K; Tredennick, Andrew T; Vargas, Rodrigo; Weathers, Kathleen C; White, Ethan P

    2018-02-13

    Two foundational questions about sustainability are "How are ecosystems and the services they provide going to change in the future?" and "How do human decisions affect these trajectories?" Answering these questions requires an ability to forecast ecological processes. Unfortunately, most ecological forecasts focus on centennial-scale climate responses, therefore neither meeting the needs of near-term (daily to decadal) environmental decision-making nor allowing comparison of specific, quantitative predictions to new observational data, one of the strongest tests of scientific theory. Near-term forecasts provide the opportunity to iteratively cycle between performing analyses and updating predictions in light of new evidence. This iterative process of gaining feedback, building experience, and correcting models and methods is critical for improving forecasts. Iterative, near-term forecasting will accelerate ecological research, make it more relevant to society, and inform sustainable decision-making under high uncertainty and adaptive management. Here, we identify the immediate scientific and societal needs, opportunities, and challenges for iterative near-term ecological forecasting. Over the past decade, data volume, variety, and accessibility have greatly increased, but challenges remain in interoperability, latency, and uncertainty quantification. Similarly, ecologists have made considerable advances in applying computational, informatic, and statistical methods, but opportunities exist for improving forecast-specific theory, methods, and cyberinfrastructure. Effective forecasting will also require changes in scientific training, culture, and institutions. The need to start forecasting is now; the time for making ecology more predictive is here, and learning by doing is the fastest route to drive the science forward.

  11. ITER ITA newsletter. No. 1, February 2003

    International Nuclear Information System (INIS)

    2003-04-01

    This first issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related meetings including eighth ITER Negotiations meeting, held on 18-19 February, 2003 in St. Petersburg, Russia, first meeting of the ITER preparatory committee, held on 17 February, 2003 in St. Petersburg, Russia and the third meeting of the ITPA (International Tokamak Physics Activity) coordinating committee, held on 24-25 October 2002 at the Max-Planck-Institut fuer Plasmaphysik, Garching

  12. ITER ITA newsletter. Special issue - December 2006

    International Nuclear Information System (INIS)

    2006-12-01

    This issue of ITER ITA (ITER transitional arrangements) newsletter contains information about signing ITER Agreement, which took place on 21 November 2006 in Paris, France. It was great day for fusion research as Ministers from the seven ITER Parties in the presence of President Jacques Chirac and President of European Commission Jose Barroso and some 400 invited guests signed the Agreement setting up the ITER International Fusion Energy Organization. This issues contains the speeches, statements and remarks of Presidents and Ministers

  13. ITER ITA newsletter. No. 11, December 2003

    International Nuclear Information System (INIS)

    2003-12-01

    This issue of the ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER including information from the editor about ITER update, about progress in ITER magnet design and preparation of procurement packages and about 25th anniversary of the First Steering Committee Meeting of the International Tokamak Reactor (INTOR) Workshop, organized under the auspices of the IAEA, took place at the IAEA Headquarters in Vienna

  14. ITER EDA newsletter. V. 5, no. 7

    International Nuclear Information System (INIS)

    1996-07-01

    This issue of the Newsletter on the Engineering Design Activities (EDA) for the ITER Tokamak project contains a report on the Tenth ITER Council Meeting, held July 24-25, 1996, in St. Petersburg, Russia; a description of the Status of the ITER EDA by the ITER Director, Dr. R. Aymar; and a report on the so-called Task Number One by the ITER Special Working Group (Basis for the Start of Explorations, presenting possible scenarios toward siting, licensing and host support)

  15. ITER ITA newsletter No. 33, August-September-October 2006

    International Nuclear Information System (INIS)

    2006-11-01

    This issue of ITER ITA (ITER transitional arrangements) newsletter contains concise information about ITER related events such as public debate on ITER in Provence and fiftieth annual General Conference of the IAEA. Eight ITER related statements were made during Conference

  16. Controlling localized spatiotemporal chaos using feedback control method

    International Nuclear Information System (INIS)

    Li Yan; Zhang Xu

    2006-01-01

    Suppression of localized spatiotemporal chaos observed in one-dimensional coupled map lattice system is achieved using feedback control [P. Parmananda, Yu. Jiang, Phys. Lett. A 231 (1997) 159; P. Parmananda, M. Hildebrand, M. Eiswirth, Phys. Rev. E 56 (1997) 239]. The control is successful both for the frozen random pattern and defect chaotic diffusion pattern. This Letter introduces a new improved feedback control method. To compare with other methods of feedback control, this method can achieve stable state with less iteration steps and more simple calculation process. We prove the stability of the controlled result by calculating maximal Lyapunov exponent. And we also find that this method is robust to small disturbance

  17. Establishment of ITER: Relevant documents

    International Nuclear Information System (INIS)

    1988-01-01

    At the Geneva Summit Meeting in November, 1985, a proposal was made by the Soviet Union to build a next-generation tokamak experiment on a collaborative basis involving the world's four major fusion blocks. In October, 1986, after consulting with Japan and the European Community, the United States responded with a proposal on how to implement such an activity. Ensuing diplomatic and technical discussions resulted in the establishment, under the auspices of the IAEA, of the International Thermonuclear Experimental Reactor Conceptual Design Activities. This tome represents a collection of all documents relating to the establishment of ITER, beginning with the initial meeting of the ITER Quadripartite Initiative Committee in Vienna on 15-16 March, 1987, through the meeting of the Provisional ITER Council, also in Vienna, on 8-9 February, 1988

  18. Remote maintenance development for ITER

    International Nuclear Information System (INIS)

    Tada, Eisuke; Shibanuma, Kiyoshi

    1997-01-01

    This paper both describes the overall design concept of the ITER remote maintenance system, which has been developed mainly for use with in-vessel components such as divertor and blanket, and outlines of the ITER R and D program, which has been established to develop remote handling equipment/tools and radiation hard components. In ITER, the reactor structures inside cryostat have to be maintained remotely because of activation due to DT operation. Therefore, remote-handling technology is fundamental, and the reactor-structure design must be made consistent with remote maintainability. The overall maintenance scenario and design concepts of the required remote handling equipment/tools have been developed according to their maintenance classification. Technologies are also being developed to verify the feasibility of the maintenance design and include fabrication and testing of a fullscale remote-handling equipment/tools for in-vessel maintenance. (author)

  19. The danger of iteration methods

    International Nuclear Information System (INIS)

    Villain, J.; Semeria, B.

    1983-01-01

    When a Hamiltonian H depends on variables phisub(i), the values of these variables which minimize H satisfy the equations deltaH/deltaphisub(i) = O. If this set of equations is solved by iteration, there is no guarantee that the solution is the one which minimizes H. In the case of a harmonic system with a random potential periodic with respect to the phisub(i)'s, the fluctuations have been calculated by Efetov and Larkin by means of the iteration method. The result is wrong in the case of a strong disorder. Even in the weak disorder case, it is wrong for a one-dimensional system and for a finite system of 2 particles. It is argued that the results obtained by iteration are always wrong, and that between 2 and 4 dimensions, spin-pair correlation functions decay like powers of the distance, as found by Aharony and Pytte for another model

  20. Spectrally Compatible Iterative Water Filling

    Science.gov (United States)

    Verlinden, Jan; Bogaert, Etienne Vanden; Bostoen, Tom; Zanier, Francesca; Luise, Marco; Cendrillon, Raphael; Moonen, Marc

    2006-12-01

    Until now static spectrum management has ensured that DSL lines in the same cable are spectrally compatible under worst-case crosstalk conditions. Recently dynamic spectrum management (DSM) has been proposed aiming at an increased capacity utilization by adaptation of the transmit spectra of DSL lines to the actual crosstalk interference. In this paper, a new DSM method for downstream ADSL is derived from the well-known iterative water-filling (IWF) algorithm. The amount of boosting of this new DSM method is limited, such that it is spectrally compatible with ADSL. Hence it is referred to as spectrally compatible iterative water filling (SC-IWF). This paper focuses on the performance gains of SC-IWF. This method is an autonomous DSM method (DSM level 1) and it will be investigated together with two other DSM level-1 algorithms, under various noise conditions, namely, iterative water-filling algorithm, and flat power back-off (flat PBO).

  1. Spectrally Compatible Iterative Water Filling

    Directory of Open Access Journals (Sweden)

    Cendrillon Raphael

    2006-01-01

    Full Text Available Until now static spectrum management has ensured that DSL lines in the same cable are spectrally compatible under worst-case crosstalk conditions. Recently dynamic spectrum management (DSM has been proposed aiming at an increased capacity utilization by adaptation of the transmit spectra of DSL lines to the actual crosstalk interference. In this paper, a new DSM method for downstream ADSL is derived from the well-known iterative water-filling (IWF algorithm. The amount of boosting of this new DSM method is limited, such that it is spectrally compatible with ADSL. Hence it is referred to as spectrally compatible iterative water filling (SC-IWF. This paper focuses on the performance gains of SC-IWF. This method is an autonomous DSM method (DSM level 1 and it will be investigated together with two other DSM level-1 algorithms, under various noise conditions, namely, iterative water-filling algorithm, and flat power back-off (flat PBO.

  2. Utilization of Short-Simulations for Tuning High-Resolution Climate Model

    Science.gov (United States)

    Lin, W.; Xie, S.; Ma, P. L.; Rasch, P. J.; Qian, Y.; Wan, H.; Ma, H. Y.; Klein, S. A.

    2016-12-01

    Many physical parameterizations in atmospheric models are sensitive to resolution. Tuning the models that involve a multitude of parameters at high resolution is computationally expensive, particularly when relying primarily on multi-year simulations. This work describes a complementary set of strategies for tuning high-resolution atmospheric models, using ensembles of short simulations to reduce the computational cost and elapsed time. Specifically, we utilize the hindcast approach developed through the DOE Cloud Associated Parameterization Testbed (CAPT) project for high-resolution model tuning, which is guided by a combination of short (global mean statistics and many spatial features are consistent between Atmospheric Model Intercomparison Project (AMIP)-type simulations and CAPT-type hindcasts, with just a small number of short-term simulations for the latter over the corresponding season. The use of CAPT hindcasts to find parameter choice for the reduction of large model biases dramatically improves the turnaround time for the tuning at high resolution. Improvement seen in CAPT hindcasts generally translates to improved AMIP-type simulations. An iterative CAPT-AMIP tuning approach is therefore adopted during each major tuning cycle, with the former to survey the likely responses and narrow the parameter space, and the latter to verify the results in climate context along with assessment in greater detail once an educated set of parameter choice is selected. Limitations on using short-term simulations for tuning climate model are also discussed.

  3. Phase tuning by length contraction.

    Science.gov (United States)

    Jin, Warren; Polcawich, Ronald G; Morton, Paul A; Bowers, John E

    2018-02-05

    Typical integrated optical phase tuners alter the effective index. In this paper, we explore tuning by geometric deformation. We show that tuning efficiency, Vπ L, improves as the device size shrinks down to the optimal bend radius, contrary to conventional index-shift based approaches where Vπ L remains constant. We demonstrate that this approach is capable of ultra-low power tuning across a full FSR in a low-confinement silicon nitride based ring resonator of 580 μm radius. We demonstrate record performance with V FSR = 16 V, Vπ L = 3.6 V dB, Vπ Lα = 1.1 V dB, tuning current below 10 nA, and unattenuated tuning response up to 1 MHz. We also present optimized designs for high confinement silicon nitride and silicon based platforms with radius down to 80 μm and 45 μm, respectively, with performance well beyond current state-of-the-art. Applications include narrow-linewidth tunable diode lasers for spectroscopy and non-linear optics, optical phased array beamforming networks for RF antennas and LIDAR, and optical filters for WDM telecommunication links.

  4. Feedback on Feedback--Does It Work?

    Science.gov (United States)

    Speicher, Oranna; Stollhans, Sascha

    2015-01-01

    It is well documented that providing assessment feedback through the medium of screencasts is favourably received by students and encourages deeper engagement with the feedback given by the language teacher (inter alia Abdous & Yoshimura, 2010; Brick & Holmes, 2008; Cann, 2007; Stannard, 2007). In this short paper we will report the…

  5. ITER ITA newsletter No. 31, June 2006

    International Nuclear Information System (INIS)

    2006-07-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about initialling the ITER Agreement and its related instruments by seven ITER parties, which too place in Brussels on 24 May 2006. The initialling constituted the final act of the ITER negotiations. It confirmed the Parties' common acceptance of the negotiated texts, ad referendum, and signalled their intentions to move forward towards the entry into force of the ITER Agreement as soon as possible. 'ITER - Uniting science today, global energy tomorrow' was the theme of a number of media events timed to accompany a remarkable day in the history of the ITER international venture, May 24th 2006, initialling of the ITER international agreement

  6. Integrated unaligned resonant modulator tuning

    Science.gov (United States)

    Zortman, William A.; Lentine, Anthony L.

    2017-10-03

    Methods and systems for tuning a resonant modulator are disclosed. One method includes receiving a carrier signal modulated by the resonant modulator with a stream of data having an approximately equal number of high and low bits, determining an average power of the modulated carrier signal, comparing the average power to a predetermined threshold, and operating a tuning device coupled to the resonant modulator based on the comparison of the average power and the predetermined threshold. One system includes an input structure, a plurality of processing elements, and a digital control element. The input structure is configured to receive, from the resonant modulator, a modulated carrier signal. The plurality of processing elements are configured to determine an average power of the modulated carrier signal. The digital control element is configured to operate a tuning device coupled to the resonant modulator based on the average power of the modulated carrier signal.

  7. ITER Neutral Beam Injection System

    International Nuclear Information System (INIS)

    Ohara, Yoshihiro; Tanaka, Shigeru; Akiba, Masato

    1991-03-01

    A Japanese design proposal of the ITER Neutral Beam Injection System (NBS) which is consistent with the ITER common design requirements is described. The injection system is required to deliver a neutral deuterium beam of 75MW at 1.3MeV to the reactor plasma and utilized not only for plasma heating but also for current drive and current profile control. The injection system is composed of 9 modules, each of which is designed so as to inject a 1.3MeV, 10MW neutral beam. The most important point in the design is that the injection system is based on the utilization of a cesium-seeded volume negative ion source which can produce an intense negative ion beam with high current density at a low source operating pressure. The design value of the source is based on the experimental values achieved at JAERI. The utilization of the cesium-seeded volume source is essential to the design of an efficient and compact neutral beam injection system which satisfies the ITER common design requirements. The critical components to realize this design are the 1.3MeV, 17A electrostatic accelerator and the high voltage DC acceleration power supply, whose performances must be demonstrated prior to the construction of ITER NBI system. (author)

  8. Status of the ITER EDA

    International Nuclear Information System (INIS)

    Aymar, R.

    1999-01-01

    This article summarises progress made in the ITER Design Activities between October 1998 and February 1999. The three main focusses of the activity were on design work, on R and D work and on the physics basis. The consequences of diminishing financial funds and personnel are discussed and the state of the individual R and D projects is given briefly

  9. Informal meeting on ITER developments

    International Nuclear Information System (INIS)

    Canobbio, E.

    2000-01-01

    The International Fusion Research Council (IFRC), advisory body of the IAEA, organized an informal meeting on the general status and outlook for ITER, held October 9 at Sorrento, Italy, in conjunction with the 18th IAEA Fusion Energy Conference. This article describes the main events at the meeting

  10. Iterative Specialisation of Horn Clauses

    DEFF Research Database (Denmark)

    Nielsen, Christoffer Rosenkilde; Nielson, Flemming; Nielson, Hanne Riis

    2008-01-01

    We present a generic algorithm for solving Horn clauses through iterative specialisation. The algorithm is generic in the sense that it can be instantiated with any decidable fragment of Horn clauses, resulting in a solution scheme for general Horn clauses that guarantees soundness and termination...

  11. ITER Council tour of Clarington site

    International Nuclear Information System (INIS)

    Dautovich, D.

    2001-01-01

    The ITER Council meeting was recently held in Toronto on 27 and 28 February. ITER Canada provided local arrangements for the Council meeting on behalf of Europe as the Official host. Following the meeting, on 1 March, ITER Canada conducted a tour of the proposed ITER construction site at Charington, and the ITER Council members attended a luncheon followed by a speech by Dr. Peter Barnard, Chairman and CEO of ITER Canada, at the Empire Club of Canada. The official invitation to participate in these events came from Dr. Peter Harrison, Deputy Minister of Natural Resources Canada. This report provides a brief summary of the events on 1 March

  12. ITER ITA Newsletter. No. 29, March 2006

    International Nuclear Information System (INIS)

    2006-05-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related activities and meetings, namely, the ITER Director-General Nominee, Dr. Kaname Ikeda, took up his position as ITER Project Leader in Cadarache on 13 March, the consolidation of information technology infrastructure for ITER and about he Thirty-Fifth Meeting of the Fusion Power Co-ordinating Committee (FPCC), which was held on 28 February-1 March 2006 at the headquarters of the International Energy Agency (IEA) in Paris

  13. ITER EDA Newsletter. V. 4, no. 7

    International Nuclear Information System (INIS)

    1995-07-01

    This ITER EDA (Engineering Design Activities) Newsletter issue contains reports on (i) the 8th meeting of the ITER Technical Advisory Committee (TAC-8) held on June 29 - July 7, 1995 at the ITER San Diego Work Site, (ii) the 8th meeting of the ITER Management Advisory Committee (MAC-8) held at the ITER San Diego Work Site on July 9-10, 1995, (iii) the 33rd meeting of the International Fusion Research Council (FRC), held July 11, 1995 at the IAEA Headquarters in Vienna, Austria, and (iv) the ITER participation in the fifth topical meeting on Tritium Technology in Fission, Fusion and Isotopic Applications

  14. Iterative Sparse Channel Estimation and Decoding for Underwater MIMO-OFDM

    Directory of Open Access Journals (Sweden)

    Berger ChristianR

    2010-01-01

    Full Text Available We propose a block-by-block iterative receiver for underwater MIMO-OFDM that couples channel estimation with multiple-input multiple-output (MIMO detection and low-density parity-check (LDPC channel decoding. In particular, the channel estimator is based on a compressive sensing technique to exploit the channel sparsity, the MIMO detector consists of a hybrid use of successive interference cancellation and soft minimum mean-square error (MMSE equalization, and channel coding uses nonbinary LDPC codes. Various feedback strategies from the channel decoder to the channel estimator are studied, including full feedback of hard or soft symbol decisions, as well as their threshold-controlled versions. We study the receiver performance using numerical simulation and experimental data collected from the RACE08 and SPACE08 experiments. We find that iterative receiver processing including sparse channel estimation leads to impressive performance gains. These gains are more pronounced when the number of available pilots to estimate the channel is decreased, for example, when a fixed number of pilots is split between an increasing number of parallel data streams in MIMO transmission. For the various feedback strategies for iterative channel estimation, we observe that soft decision feedback slightly outperforms hard decision feedback.

  15. Incoherent and coherent tune shifts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.Y. [Brookhaven National Lab., Upton, NY (United States). AGS Dept.

    1995-12-31

    The longitudinal and transverse microwave instabilities are the two important limiting factors for the performance of an accelerator. Comparing with the fairly unified approach for the longitudinal microwave instabilities, different approaches have been used to define the transverse microwave instabilities. One reason of this is related to the role played by the space charge incoherent and coherent tune shifts. In this article, the transverse microwave instabilities will be discussed by defining separately the roles of the space charge incoherent and coherent tunes, which are represented by the space charge transverse impedances. Preliminary results for the AGS as proton driver are presented by using this approach.

  16. A linear iterative unfolding method

    International Nuclear Information System (INIS)

    László, András

    2012-01-01

    A frequently faced task in experimental physics is to measure the probability distribution of some quantity. Often this quantity to be measured is smeared by a non-ideal detector response or by some physical process. The procedure of removing this smearing effect from the measured distribution is called unfolding, and is a delicate problem in signal processing, due to the well-known numerical ill behavior of this task. Various methods were invented which, given some assumptions on the initial probability distribution, try to regularize the unfolding problem. Most of these methods definitely introduce bias into the estimate of the initial probability distribution. We propose a linear iterative method (motivated by the Neumann series / Landweber iteration known in functional analysis), which has the advantage that no assumptions on the initial probability distribution is needed, and the only regularization parameter is the stopping order of the iteration, which can be used to choose the best compromise between the introduced bias and the propagated statistical and systematic errors. The method is consistent: 'binwise' convergence to the initial probability distribution is proved in absence of measurement errors under a quite general condition on the response function. This condition holds for practical applications such as convolutions, calorimeter response functions, momentum reconstruction response functions based on tracking in magnetic field etc. In presence of measurement errors, explicit formulae for the propagation of the three important error terms is provided: bias error (distance from the unknown to-be-reconstructed initial distribution at a finite iteration order), statistical error, and systematic error. A trade-off between these three error terms can be used to define an optimal iteration stopping criterion, and the errors can be estimated there. We provide a numerical C library for the implementation of the method, which incorporates automatic

  17. Low Complexity V-BLAST MIMO-OFDM Detector by Successive Iterations Reduction

    Directory of Open Access Journals (Sweden)

    AHMED, K.

    2015-02-01

    Full Text Available V-BLAST detection method suffers large computational complexity due to its successive detection of symbols. In this paper, we propose a modified V-BLAST algorithm to decrease the computational complexity by reducing the number of detection iterations required in MIMO communication systems. We begin by showing the existence of a maximum number of iterations, beyond which, no significant improvement is obtained. We establish a criterion for the number of maximum effective iterations. We propose a modified algorithm that uses the measured SNR to dynamically set the number of iterations to achieve an acceptable bit-error rate. Then, we replace the feedback algorithm with an approximate linear function to reduce the complexity. Simulations show that significant reduction in computational complexity is achieved compared to the ordinary V-BLAST, while maintaining a good BER performance.

  18. Analysis of ITER upper port plug remote handling maintenance scenarios

    International Nuclear Information System (INIS)

    Koning, J.F.; Baar, M.R. de; Elzendoorn, B.S.Q.; Heemskerk, C.J.M.; Ronden, D.M.S.; Schuth, W.J.

    2012-01-01

    Highlights: ► Remote Handling Study Centre: providing RH compatibility analysis. ► Simulation: virtual reality including kinematics and realtime physics simulator. ► Applied on analysis of RH compatibility of Upper Launcher component replacement. ► Resulting in lowered maintenance procedure time and lessons learned. - Abstract: The ITER tokamak has a modular design, with port plugs, blanket modules and divertor cassettes. This set-up allows for maintenance of diagnostics, heating systems and first wall elements. The maintenance can be done in situ, or in the Hot Cell. Safe and effective remote handling (RH) will be ensured by the RH requirements and standards. Compliance is verified through remote handling compatibility assessments at the ITER Design Review milestones. The Remote Handling Study Centre at FOM Institute DIFFER is created to study ITER RH maintenance processes at different levels of complexity, from relatively simple situational awareness checks using snap-shots in the CAD system, time studies using virtual reality (VR) animations, to extensive operational sequence validation with multiple operators in real-time. The multi-operator facility mimics an RH work-cell as presently foreseen in the ITER RH control room. Novel VR technology is used to create a realistic setting in which a team of RH operators can interact with virtual ITER environments. A physics engine is used to emulate real-time contact interaction as to provide realistic haptic feed-back. Complex interactions between the RH operators and the control room system software are tested. RH task performance is quantified and operational resource usage estimated. The article provides a description and lessons learned from a recent study on replacement of the Steering Mirror Assembly on the ECRH (Electron Cyclotron Resonance Heating) Upper Launcher port plug.

  19. Rateless feedback codes

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Koike-Akino, Toshiaki; Orlik, Philip

    2012-01-01

    This paper proposes a concept called rateless feedback coding. We redesign the existing LT and Raptor codes, by introducing new degree distributions for the case when a few feedback opportunities are available. We show that incorporating feedback to LT codes can significantly decrease both...... the coding overhead and the encoding/decoding complexity. Moreover, we show that, at the price of a slight increase in the coding overhead, linear complexity is achieved with Raptor feedback coding....

  20. ITER EDA Newsletter. Vol. 1, No. 1

    International Nuclear Information System (INIS)

    1992-11-01

    After the ITER Engineering Design Activities (EDA) Agreement and Protocol 1 had been signed by the four ITER parties on July 21, 1992 and had entered into force, the ITER Council suggested at its first meeting (Vienna, September 10-11, 1992) that the publication of the ITER Newsletter be continued during the EDA with assistance of the International Atomic Energy Agency. This suggestion was supported by the Agency and subsequently the ITER office in Vienna assumed its responsibilities for planning and executing activities related to the publication of the Newsletter. The ITER EDA Newsletter is planned to be a monthly publication aimed at disseminating broad information and understanding, including the description of the personal and institutional involvements in the ITER project in addition to technical facts about it. The responsibility for the Newsletter rests with the ITER council. In this first issue the signing of the ITER EDA Activities and Protocol 1 is reported. The EDA organizational structure is described. This issue also reports on the first ITER EDA council meeting, the opening of the ITER EDA NAKA Co-Centre, the first meeting of the ITER Technical Advisory Committee, activities of special working groups, an ITER Technical Meeting, as well as ''News in Brief'' and ''Coming Events''

  1. The Mythology of Feedback

    Science.gov (United States)

    Adcroft, Andy

    2011-01-01

    Much of the general education and discipline-specific literature on feedback suggests that it is a central and important element of student learning. This paper examines feedback from a social process perspective and suggests that feedback is best understood through an analysis of the interactions between academics and students. The paper argues…

  2. Remote tuning of NMR probe circuits.

    Science.gov (United States)

    Kodibagkar, V D; Conradi, M S

    2000-05-01

    There are many circumstances in which the probe tuning adjustments cannot be located near the rf NMR coil. These may occur in high-temperature NMR, low-temperature NMR, and in the use of magnets with small diameter access bores. We address here circuitry for connecting a fixed-tuned probe circuit by a transmission line to a remotely located tuning network. In particular, the bandwidth over which the probe may be remotely tuned while keeping the losses in the transmission line acceptably low is considered. The results show that for all resonant circuit geometries (series, parallel, series-parallel), overcoupling of the line to the tuned circuit is key to obtaining a large tuning bandwidth. At equivalent extents of overcoupling, all resonant circuit geometries have nearly equal remote tuning bandwidths. Particularly for the case of low-loss transmission line, the tuning bandwidth can be many times the tuned circuit's bandwidth, f(o)/Q. Copyright 2000 Academic Press.

  3. How does culture affect experiential training feedback in exported Canadian health professional curricula?

    Science.gov (United States)

    Wilbur, Kerry; Mousa Bacha, Rasha; Abdelaziz, Somaia

    2017-03-17

    To explore feedback processes of Western-based health professional student training curricula conducted in an Arab clinical teaching setting. This qualitative study employed document analysis of in-training evaluation reports (ITERs) used by Canadian nursing, pharmacy, respiratory therapy, paramedic, dental hygiene, and pharmacy technician programs established in Qatar. Six experiential training program coordinators were interviewed between February and May 2016 to explore how national cultural differences are perceived to affect feedback processes between students and clinical supervisors. Interviews were recorded, transcribed, and coded according to a priori cultural themes. Document analysis found all programs' ITERs outlined competency items for students to achieve. Clinical supervisors choose a response option corresponding to their judgment of student performance and may provide additional written feedback in spaces provided. Only one program required formal face-to-face feedback exchange between students and clinical supervisors. Experiential training program coordinators identified that no ITER was expressly culturally adapted, although in some instances, modifications were made for differences in scopes of practice between Canada and Qatar.  Power distance was recognized by all coordinators who also identified both student and supervisor reluctance to document potentially negative feedback in ITERs. Instances of collectivism were described as more lenient student assessment by clinical supervisors of the same cultural background. Uncertainty avoidance did not appear to impact feedback processes. Our findings suggest that differences in specific cultural dimensions between Qatar and Canada have implications on the feedback process in experiential training which may be addressed through simple measures to accommodate communication preferences.

  4. Meeting of the ITER Council

    International Nuclear Information System (INIS)

    Drew, M.

    2001-01-01

    Full text: A meeting of the ITER Council took place in Toronto, Canada, on 27-28 February 2001 (Canada participates in the ITER EDA as an associate of the EU Party). The delegations to the Council were led by Dr. U. Finzi, Principal Advisor in charge of Fusion R and D in the Directorate-General for Research of the European Commission, Mr. T. Sugawa, Deputy Director-General of the Research and Development Bureau of the Ministry of Education, Culture, Sport, Science and Technology of Japan, and Academician E. Velikhov, President of the RRC ''Kurchatov Institute''. The European delegation was joined by Canadian experts including a representative from the Canadian Department of Natural Resources. The Council heard presentations from Dr. H. Kishimoto on the successful completion of the Explorations concerning future joint implementation of ITER, and from Dr. J.-P. Rager on the ITER International Industry Liaison Meeting held in Toronto in November 2000. Having noted statements of Parties' status, in particular concerning the readiness to start negotiations and the progress toward site offers, the Council encouraged the Parties to pursue preparations toward future implementation of ITER along the general lines proposed in the Explorers' final report. The Council also noted the readiness the of the RF and EU Parties to instruct specified current JCT members to remain at their places of assignment after the end of the EDA, in preparation for a transition to the Co-ordinated Technical Activities foreseen as support to ITER negotiations. The Council was pleased to hear that meetings with the Director of the ITER Parties' Designated Safety Representatives had started, and commended the progress toward achieving timely licensing processes with a good common understanding. The Council noted with appreciation the Director's view that no difficulties of principle in the licensing approach had been identified during the informal discussions with the regulatory representatives and

  5. Political Tunings of the Piano

    DEFF Research Database (Denmark)

    Højlund, Marie Koldkjær; Riis, Morten S.

    According to Timothy Morton the creation of ambient art posses an inherent critical potential similar to the ambiguity of the dialectical image found in the writings of Walter Benjamin. Subscribing to an object-oriented ontological understanding of how objects are riven between essence and appear......) as unfolding the ambiguity of various political tunings of the piano....

  6. Tuning History in Latin America

    Science.gov (United States)

    Velázquez Albo, Marco

    2017-01-01

    This article analyses the development and achievements of the area of History in the Tuning-Latin America Project from its launch in 2004 to its completion in 2013. Through two phases and nine general meetings, academics from Argentina, Brazil, Chile, Colombia, Costa Rica, Cuba, Guatemala, Mexico and Peru, along with academics from Spain, Portugal…

  7. ITER EDA newsletter. V. 2, no. 11

    International Nuclear Information System (INIS)

    1993-11-01

    This issue of the ITER EDA (Engineering Design Activities) Newsletter contains an ITER EDA Status Report, and a report on the Fourth International Fusion Neutronics Workshop at the University of California, Los Angeles Campus, October 20-21, 1993

  8. Iterative perceptual learning for social behavior synthesis

    NARCIS (Netherlands)

    de Kok, I.A.; Poppe, Ronald Walter; Heylen, Dirk K.J.

    We introduce Iterative Perceptual Learning (IPL), a novel approach to learn computational models for social behavior synthesis from corpora of human–human interactions. IPL combines perceptual evaluation with iterative model refinement. Human observers rate the appropriateness of synthesized

  9. Iterative Perceptual Learning for Social Behavior Synthesis

    NARCIS (Netherlands)

    de Kok, I.A.; Poppe, Ronald Walter; Heylen, Dirk K.J.

    We introduce Iterative Perceptual Learning (IPL), a novel approach for learning computational models for social behavior synthesis from corpora of human-human interactions. The IPL approach combines perceptual evaluation with iterative model refinement. Human observers rate the appropriateness of

  10. ITER EDA newsletter. V. 5, no. 8

    International Nuclear Information System (INIS)

    1996-08-01

    This issue of the Newsletter on the Engineering Design Activities (EDA) for the ITER Tokamak project contains a report on the divertor remote handling development (and of a summer party at the ITER Joint Work Site in Garching, Germany)

  11. ITER EDA newsletter. V. 7, special issue

    International Nuclear Information System (INIS)

    1998-07-01

    In conjunction with the ITER Council Meeting, a ceremony was held at the IAEA Headquarters in Vienna on 22 July 1998 to celebrate the achievements of the ITER Engineering Design Activities during the period 1992-1998

  12. ITER EDA newsletter. V. 6, no. 12

    International Nuclear Information System (INIS)

    1997-12-01

    This issue of the ITER Newsletter contains summary reports (i) on the Sixth ITER Technical Meeting on Safety and Environment and (ii) on JAERI's Annual Public Seminar on Fusion Research and Development

  13. ITER EDA newsletter. V. 8, no. 7

    International Nuclear Information System (INIS)

    1999-07-01

    This newsletter contains an article concerning the ITER divertor cassette project meeting in Bologna, Italy (May 26-28, 1999), and an emotional outburst, concerning the closure of the ITER site in San Diego, USA

  14. Fault Tolerant Feedback Control

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2001-01-01

    An architecture for fault tolerant feedback controllers based on the Youla parameterization is suggested. It is shown that the Youla parameterization will give a residual vector directly in connection with the fault diagnosis part of the fault tolerant feedback controller. It turns out...... that there is a separation be-tween the feedback controller and the fault tolerant part. The closed loop feedback properties are handled by the nominal feedback controller and the fault tolerant part is handled by the design of the Youla parameter. The design of the fault tolerant part will not affect the design...

  15. ITER EDA newsletter. V. 5, no. 10

    International Nuclear Information System (INIS)

    1996-10-01

    This issue of the newsletter on the Engineering Design Activities (EDA) for the ITER Tokamak project contains a report on the Fifth ITER Technical Meeting on Safety, Environment, and Regulatory Approval, held September 29 - October 7, 1996 at the ITER San Diego Joint Work Site; and a report on the Fifth ITER Diagnostics Expert Group Workshop and Technical Meeting on Diagnostics held in Montreal, Canada, 12-13 October 1996

  16. ITER EDA newsletter. V. 9, no. 8

    International Nuclear Information System (INIS)

    2000-08-01

    This ITER EDA Newsletter reports on the ITER meeting on 29-30 June 2000 in Moscow, summarizes the status report on the ITER EDA by R. Aymar, the ITER Director, and gives overviews of the expert group workshop on transport and internal barrier physics, confinement database and modelling and edge and pedestal physics, and the IEA workshop on transport barriers at edge and core. Individual abstracts have been prepared

  17. ITER EDA newsletter. V. 5, no. 5

    International Nuclear Information System (INIS)

    1996-05-01

    This issues of the ITER Engineering Design Activities Newsletter contains a report on the Tenth Meeting of the ITER Management Advisory Committee held at JAERI Headquarters, Tokyo, June 5-6, 1996; on the Fourth ITER Divertor Physics and Divertor Modelling and Database Expert Group Workshop, held at the San Diego ITER Joint Worksite, March 11-15, 1996, and on the Agenda for the 16th IAEA Fusion Energy Conference (7-11 October 1996)

  18. ITER EDA newsletter. V. 9, no. 11

    International Nuclear Information System (INIS)

    2000-11-01

    This issue of the ITER EDA Newsletter contains discussions of three meetings, i.e., (1) the Third ITER International Industry Liaison Meeting held in Toronto, Canada (November 7-9, 2000), (2) an informal meeting on ITER developments held in Sorrento, Italy (October 9, 2000), and (3) the Thirteenth Meeting of the ITER Physics Expert Group on Diagnostics held in Naka, Japan (September 21-22, 2000)

  19. Colorado Conference on iterative methods. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The conference provided a forum on many aspects of iterative methods. Volume I topics were:Session: domain decomposition, nonlinear problems, integral equations and inverse problems, eigenvalue problems, iterative software kernels. Volume II presents nonsymmetric solvers, parallel computation, theory of iterative methods, software and programming environment, ODE solvers, multigrid and multilevel methods, applications, robust iterative methods, preconditioners, Toeplitz and circulation solvers, and saddle point problems. Individual papers are indexed separately on the EDB.

  20. Tuning a microcavity-coupled terahertz laser

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, Fabrizio; Bianchi, Vezio; Vitiello, Miriam S., E-mail: miriam.vitiello@sns.it [NEST, CNR-Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa (Italy); Li, Lianhe; Zhu, Jingxuan; Linfield, Edmund H.; Giles Davies, A. [School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Tredicucci, Alessandro [Dipartimento di Fisica, Università degli Studi di Pisa, Largo Pontecorvo 6, 56127 Pisa (Italy)

    2015-12-28

    Tunable oscillators are a key component of almost all electronic and photonic systems. Yet, a technology capable of operating in the terahertz (THz)-frequency range and fully suitable for widescale implementation is still lacking. This issue is significantly limiting potential THz applications in gas sensing, high-resolution spectroscopy, hyper-spectral imaging, and optical communications. The THz quantum cascade laser is arguably the most promising solution in terms of output power and spectral purity. In order to achieve reliable, repeatable, and broad tunability, here we exploit the strong coupling between two different cavity mode concepts: a distributed feedback one-dimensional photonic resonator (providing gain) and a mechanically actuated wavelength-size microcavity (providing tuning). The result is a continuously tunable, single-mode emitter covering a 162 GHz spectral range, centered on 3.2 THz. Our source has a few tens of MHz resolution, extremely high differential efficiency, and unprecedented compact and simple design architecture. By unveiling the large potential that lies in this technique, our results provide a robust platform for radically different THz systems exploiting broadly tunable semiconductor lasers.

  1. Feedback and Incentives

    DEFF Research Database (Denmark)

    Eriksson, Tor Viking; Poulsen, Anders; Villeval, Marie Claire

    2009-01-01

    This paper experimentally investigates the impact of different pay schemes and relative performance feedback policies on employee effort. We explore three feedback rules: no feedback on relative performance, feedback given halfway through the production period, and continuously updated feedback. We...... use two pay schemes, a piece rate and a tournament. We find that overall feedback does not improve performance. In contrast to the piece-rate pay scheme there is some evidence of positive peer effects in tournaments since the underdogs almost never quit the competition even when lagging significantly...... behind, and front runners do not slack off. But in both pay schemes relative performance feedback reduces the quality of the low performers' work; we refer to this as a "negative quality peer effect"....

  2. ITER EDA newsletter. V. 7, no. 12

    International Nuclear Information System (INIS)

    1998-12-01

    This edition of the ITER EDA Newsletter is dedicated to celebrate the achievements of the ITER activities at the San Diego Joint Work Site. Articles by E. Velikhov, A. Davies and R. Aymar mark the final days of American participation in the ITER program

  3. ITER ITA newsletter. No. 21, April 2005

    International Nuclear Information System (INIS)

    2005-05-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about Russian federation Participant Team's activity in the area of preparation for ITER construction and information about International Fusion materials irradiation Facility(IRMIF) project and prospects for implementation

  4. ITER EDA newsletter. V. 2, no. 12

    International Nuclear Information System (INIS)

    1993-12-01

    This issue of the ITER EDA (Engineering Design Activities) Newsletter contains a report of the Second ITER Technical Committee Meeting on Safety, Environment, and Regulatory Approval, San Diego, USA, November 3-12, 1993, and a summary report on an ITER Magnet Technical Meeting, Naka, Japan, October 5-8, 1993

  5. ITER EDA newsletter. V. 7, no. 10

    International Nuclear Information System (INIS)

    1998-10-01

    This newsletter contains three articles, namely a report on an ITER meeting (October 20-21,1998) in Yokohama, Japan, a short note on the 17th IAEA Fusion Energy Conference (October 19-24, 1998) in Yokohama and a monograph by ITER Director R. Aymar on 'the Legacy of Artsimovitch and the lessons of ITER'

  6. ITER EDA newsletter. V. 8, no. 11

    International Nuclear Information System (INIS)

    1999-11-01

    This ITER EDA Newsletter contains summary reports on the eleventh meeting of the ITER diagnostic expert group in Cadarache, France, on the ITER JCT presentation at the international conference on fusion reactor materials in Colorado Springs, USA and on the seventh workshop on plasma edge theory in fusion devices in Tajimi, Japan. Individual abstracts are prepared for the three contributions

  7. ITER EDA newsletter. V. 6, no. 2

    International Nuclear Information System (INIS)

    1997-02-01

    This issue of the ITER EDA (Engineering Design Activities) Newsletter reports on the ITER divertor development project and its objectives; contains a report on the 16th Energy IAEA Fusion Conference (ITER and other Tokamak Issues) held in Montreal, Canada; 287 papers were selected by the Programme Committee for presentation and 178 posters were presented. 3 figs

  8. ITER EDA newsletter. V. 9, no. 9

    International Nuclear Information System (INIS)

    2000-09-01

    This ITER EDA Newsletter contains the following 5 contributions: CSMC and CSIC charging tests successfully completed; The ITER divertor cassette project meeting; Blanket R and D and design task meeting; IAEA technical committee meeting on fusion safety; ITER L-6 large project ''blanket remote handling and maintenance''

  9. Final ITER CTA project board meeting

    International Nuclear Information System (INIS)

    Vlasenkov, V.

    2003-01-01

    The final ITER CTA Project Board Meeting (PB) took place in Barcelona, Spain on 8 December 2002. The PB took notes of the comments concerning the status of the International Team and the Participants Teams, including Dr. Aymar's report 'From ITER to a FUSION Power Reactor' and the assessment of the ITER project cost estimate

  10. ITER EDA newsletter. V. 10, no. 3

    International Nuclear Information System (INIS)

    2001-03-01

    This issue contains a report on the meeting of the ITER Council (M. Drew), a report on the ITER EDA status (Dr. R. Aymar), a report on the ITER Council tour of the Clarington Site (Dr. D. Dautovich) . Abstracts of the indivdual reports have been included in the database

  11. ITER EDA newsletter. V. 2, no. 9

    International Nuclear Information System (INIS)

    1993-09-01

    This ITER EDA (Engineering Design Activities) Newsletter issue contains a report on the third meeting of the ITER Technical Advisory Committee, a summary report for the ITER Magnetic Technical Meeting, a brief account of the International Workshop on Nuclear Data for Fusion Reactor Technology, and a description of approved arrangements for visiting home team personnel

  12. ITER EDA Newsletter. V. 2, no. 1

    International Nuclear Information System (INIS)

    1993-01-01

    This ITER EDA (Engineering Design Activities) Newsletter issue is dedicated to the description of the ITER EDA Home Teams (European Community, Japan, Russian Federation, USA), in particular their composition, tasks, responsibilities, national support and activities, aimed to design the ITER tokamak

  13. The international thermonuclear reactor (ITER)

    International Nuclear Information System (INIS)

    Fowler, T.K.; Henning, C.D.

    1987-01-01

    Four governmental groups, representing Europe, Japan, USSR and U.S. met in March 1987 to consider a new international design of a magnetic fusion device for the 1990's. An interim group was appointed. The author gives a brief synopsis of what might be thought of as a draft charter. The starting point is the objective of the ITER device, which is summarized as demonstrating both scientific and technical feasibility of fusion. The paper presents an update on the current thinking and technical aspects for the International Thermonuclear Experimental Reactor (ITER). This covers not only what is happening in the U.S. but also some reports of preliminary thinking of the last technical work that occurred in Vienna

  14. ITER-FEAT outline design report

    International Nuclear Information System (INIS)

    2001-01-01

    In July 1998 the ITER Parties were unable, for financial reasons, to proceed with construction of the ITER design proposed at that time, to meet the detailed technical objectives and target cost set in 1992. It was therefore decided to investigate options for the design of ITER with reduced technical objectives and with possibly decreased technical margins, whose target construction cost was one half that of the 1998 ITER design, while maintaining the overall programmatic objective. To identify designs that might meet the revised objectives, task forces involving the JCT and Home Teams met during 1998 and 1999 to analyse and compare a range of options for the design of such a device. This led at the end of 1999 to a single configuration for the ITER design with parameters considered to be the most credible consistent with technical limitations and the financial target, yet meeting fully the objectives with appropriate margins. This new design of ITER, called ''ITER-FEAT'', was submitted to the ITER Director to the ITER Parties as the ''ITER-FEAT Outline Design Report'' (ODR) in January 2000, at their meeting in Tokyo. The Parties subsequently conducted their domestic assessments of this report and fed the resulting comments back into the progressing design. The progress on the developing design was reported to the ITER Technical Advisory Committee (TAC) in June 2000 in the report ''Progress in Resolving Open Design Issues from the ODR'' alongside a report on Progress in Technology R and D for ITER. In addition, the progress in the ITER-FEAT Design and Validating R and D was reported to the ITER Parties. The ITER-FEAT design was subsequently approved by the governing body of ITER in Moscow in June 2000 as the basis for the preparation of the Final Design Report, recognising it as a single mature design for ITER consistent with its revised objectives. This volume contains the documents pertinent to the process described above. More detailed technical information

  15. US ITER limiter module design

    International Nuclear Information System (INIS)

    Mattas, R.F.; Billone, M.; Hassanein, A.

    1996-08-01

    The recent U.S. effort on the ITER (International Thermonuclear Experimental Reactor) shield has been focused on the limiter module design. This is a multi-disciplinary effort that covers design layout, fabrication, thermal hydraulics, materials evaluation, thermo- mechanical response, and predicted response during off-normal events. The results of design analyses are presented. Conclusions and recommendations are also presented concerning, the capability of the limiter modules to meet performance goals and to be fabricated within design specifications using existing technology

  16. Truncated States Obtained by Iteration

    International Nuclear Information System (INIS)

    Cardoso, W. B.; Almeida, N. G. de

    2008-01-01

    We introduce the concept of truncated states obtained via iterative processes (TSI) and study its statistical features, making an analogy with dynamical systems theory (DST). As a specific example, we have studied TSI for the doubling and the logistic functions, which are standard functions in studying chaos. TSI for both the doubling and logistic functions exhibit certain similar patterns when their statistical features are compared from the point of view of DST

  17. Matlab modeling of ITER CODAC

    International Nuclear Information System (INIS)

    Pangione, L.; Lister, J.B.

    2008-01-01

    The ITER CODAC (COntrol, Data Access and Communication) conceptual design resulted from 2 years of activity. One result was a proposed functional partitioning of CODAC into different CODAC Systems, each of them partitioned into other CODAC Systems. Considering the large size of this project, simple use of human language assisted by figures would certainly be ineffective in creating an unambiguous description of all interactions and all relations between these Systems. Moreover, the underlying design is resident in the mind of the designers, who must consider all possible situations that could happen to each system. There is therefore a need to model the whole of CODAC with a clear and preferably graphical method, which allows the designers to verify the correctness and the consistency of their project. The aim of this paper is to describe the work started on ITER CODAC modeling using Matlab/Simulink. The main feature of this tool is the possibility of having a simple, graphical, intuitive representation of a complex system and ultimately to run a numerical simulation of it. Using Matlab/Simulink, each CODAC System was represented in a graphical and intuitive form with its relations and interactions through the definition of a small number of simple rules. In a Simulink diagram, each system was represented as a 'black box', both containing, and connected to, a number of other systems. In this way it is possible to move vertically between systems on different levels, to show the relation of membership, or horizontally to analyse the information exchange between systems at the same level. This process can be iterated, starting from a global diagram, in which only CODAC appears with the Plant Systems and the external sites, and going deeper down to the mathematical model of each CODAC system. The Matlab/Simulink features for simulating the whole top diagram encourage us to develop the idea of completing the functionalities of all systems in order to finally have a full

  18. ITER merges energies in Provence

    International Nuclear Information System (INIS)

    Barla, J.Ch.

    2009-01-01

    The works around the Cadarache site where the experimental nuclear fusion reactor ITER is to be built have already generated about 366 million euros of contracts and provisions with French companies by September 30, 2009. The advance of the project should bring 3000 to 4000 persons more around the site but the Provence region suffers from the lack of a real projected management of employment and skills. (J.S.)

  19. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    International Nuclear Information System (INIS)

    Farias, G.; Dormido-Canto, S.; Vega, J.; Santos, M.; Pastor, I.; Fingerhuth, S.; Ascencio, J.

    2014-01-01

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process

  20. Iterative noise removal from temperature and density profiles in the TJ-II Thomson scattering

    Energy Technology Data Exchange (ETDEWEB)

    Farias, G., E-mail: gonzalo.farias@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Dormido-Canto, S., E-mail: sebas@dia.uned.es [Departamento de Informática y Automática, UNED, 28040 Madrid (Spain); Vega, J., E-mail: jesus.vega@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Santos, M., E-mail: msantos@ucm.es [Departamento de Arquitectura de Computadores y Automática, Universidad Complutense de Madrid, 28040 Madrid (Spain); Pastor, I., E-mail: ignacio.pastor@ciemat.es [Asociación EURATOM/CIEMAT para Fusión, Avd. Complutense 22, 28040 Madrid (Spain); Fingerhuth, S., E-mail: sebastian.fingerhuth@ucv.cl [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile); Ascencio, J., E-mail: j_ascencio21@hotmail.com [Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso (Chile)

    2014-05-15

    TJ-II Thomson Scattering diagnostic provides temperature and density profiles of plasma. The CCD camera acquires images that are corrupted with some kind of noise called stray-light. This noise degrades both image contrast and measurement accuracy, which could produce unreliable profiles of the diagnostic. So far, several approaches have been applied in order to decrease the noise in the TJ-II Thomson scattering images. Since the presence of the noise is not global but located in some particular regions of the image, advanced processing techniques are needed. However such methods require of manual fine-tuning of parameters to reach a good performance. In this contribution, an iterative image processing approach is applied in order to reduce the stray light effects in the images of the TJ-II Thomson scattering diagnostic. The proposed solution describes how the noise can be iteratively reduced in the images when a key parameter is automatically adjusted during the iterative process.

  1. Convergence of SART + OS + TV iterative reconstruction algorithm for optical CT imaging of gel dosimeters

    International Nuclear Information System (INIS)

    Du, Yi; Yu, Gongyi; Xiang, Xincheng; Wang, Xiangang; De Deene, Yves

    2017-01-01

    Computational simulations are used to investigate the convergence of a hybrid iterative algorithm for optical CT reconstruction, i.e. the simultaneous algebraic reconstruction technique (SART) integrated with ordered subsets (OS) iteration and total variation (TV) minimization regularization, or SART+OS+TV for short. The influence of parameter selection to reach convergence, spatial dose gradient integrity, MTF and convergent speed are discussed. It’s shown that the results of SART+OS+TV algorithm converge to the true values without significant bias, and MTF and convergent speed are affected by different parameter sets used for iterative calculation. In conclusion, the performance of the SART+OS+TV depends on parameter selection, which also implies that careful parameter tuning work is required and necessary for proper spatial performance and fast convergence. (paper)

  2. Convergence of SART + OS + TV iterative reconstruction algorithm for optical CT imaging of gel dosimeters

    Science.gov (United States)

    Du, Yi; Yu, Gongyi; Xiang, Xincheng; Wang, Xiangang; De Deene, Yves

    2017-05-01

    Computational simulations are used to investigate the convergence of a hybrid iterative algorithm for optical CT reconstruction, i.e. the simultaneous algebraic reconstruction technique (SART) integrated with ordered subsets (OS) iteration and total variation (TV) minimization regularization, or SART+OS+TV for short. The influence of parameter selection to reach convergence, spatial dose gradient integrity, MTF and convergent speed are discussed. It’s shown that the results of SART+OS+TV algorithm converge to the true values without significant bias, and MTF and convergent speed are affected by different parameter sets used for iterative calculation. In conclusion, the performance of the SART+OS+TV depends on parameter selection, which also implies that careful parameter tuning work is required and necessary for proper spatial performance and fast convergence.

  3. ITER Plasma Control System Development

    Science.gov (United States)

    Snipes, Joseph; ITER PCS Design Team

    2015-11-01

    The development of the ITER Plasma Control System (PCS) continues with the preliminary design phase for 1st plasma and early plasma operation in H/He up to Ip = 15 MA in L-mode. The design is being developed through a contract between the ITER Organization and a consortium of plasma control experts from EU and US fusion laboratories, which is expected to be completed in time for a design review at the end of 2016. This design phase concentrates on breakdown including early ECH power and magnetic control of the poloidal field null, plasma current, shape, and position. Basic kinetic control of the heating (ECH, ICH, NBI) and fueling systems is also included. Disruption prediction, mitigation, and maintaining stable operation are also included because of the high magnetic and kinetic stored energy present already for early plasma operation. Support functions for error field topology and equilibrium reconstruction are also required. All of the control functions also must be integrated into an architecture that will be capable of the required complexity of all ITER scenarios. A database is also being developed to collect and manage PCS functional requirements from operational scenarios that were defined in the Conceptual Design with links to proposed event handling strategies and control algorithms for initial basic control functions. A brief status of the PCS development will be presented together with a proposed schedule for design phases up to DT operation.

  4. Feature-Specific Organization of Feedback Pathways in Mouse Visual Cortex.

    Science.gov (United States)

    Huh, Carey Y L; Peach, John P; Bennett, Corbett; Vega, Roxana M; Hestrin, Shaul

    2018-01-08

    Higher and lower cortical areas in the visual hierarchy are reciprocally connected [1]. Although much is known about how feedforward pathways shape receptive field properties of visual neurons, relatively little is known about the role of feedback pathways in visual processing. Feedback pathways are thought to carry top-down signals, including information about context (e.g., figure-ground segmentation and surround suppression) [2-5], and feedback has been demonstrated to sharpen orientation tuning of neurons in the primary visual cortex (V1) [6, 7]. However, the response characteristics of feedback neurons themselves and how feedback shapes V1 neurons' tuning for other features, such as spatial frequency (SF), remain largely unknown. Here, using a retrograde virus, targeted electrophysiological recordings, and optogenetic manipulations, we show that putatively feedback neurons in layer 5 (hereafter "L5 feedback") in higher visual areas, AL (anterolateral area) and PM (posteromedial area), display distinct visual properties in awake head-fixed mice. AL L5 feedback neurons prefer significantly lower SF (mean: 0.04 cycles per degree [cpd]) compared to PM L5 feedback neurons (0.15 cpd). Importantly, silencing AL L5 feedback reduced visual responses of V1 neurons preferring low SF (mean change in firing rate: -8.0%), whereas silencing PM L5 feedback suppressed responses of high-SF-preferring V1 neurons (-20.4%). These findings suggest that feedback connections from higher visual areas convey distinctly tuned visual inputs to V1 that serve to boost V1 neurons' responses to SF. Such like-to-like functional organization may represent an important feature of feedback pathways in sensory systems and in the nervous system in general. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Chatter suppression methods of a robot machine for ITER vacuum vessel assembly and maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Huapeng; Wang, Yongbo, E-mail: yongbo.wang@lut.fi; Li, Ming; Al-Saedi, Mazin; Handroos, Heikki

    2014-10-15

    Highlights: •A redundant 10-DOF serial-parallel hybrid robot for ITER assembly and maintains is presented. •A dynamic model of the robot is developed. •A feedback and feedforward controller is presented to suppress machining vibration of the robot. -- Abstract: In the process of assembly and maintenance of ITER vacuum vessel (ITER VV), various machining tasks including threading, milling, welding-defects cutting and flexible hose boring are required to be performed from inside of ITER VV by on-site machining tools. Robot machine is a promising option for these tasks, but great chatter (machine vibration) would happen in the machining process. The chatter vibration will deteriorate the robot accuracy and surface quality, and even cause some damages on the end-effector tools and the robot structure itself. This paper introduces two vibration control methods, one is passive and another is active vibration control. For the passive vibration control, a parallel mechanism is presented to increase the stiffness of robot machine; for the active vibration control, a hybrid control method combining feedforward controller and nonlinear feedback controller is introduced for chatter suppression. A dynamic model and its chatter vibration phenomena of a hybrid robot is demonstrated. Simulation results are given based on the proposed hybrid robot machine which is developed for the ITER VV assembly and maintenance.

  6. Chatter suppression methods of a robot machine for ITER vacuum vessel assembly and maintenance

    International Nuclear Information System (INIS)

    Wu, Huapeng; Wang, Yongbo; Li, Ming; Al-Saedi, Mazin; Handroos, Heikki

    2014-01-01

    Highlights: •A redundant 10-DOF serial-parallel hybrid robot for ITER assembly and maintains is presented. •A dynamic model of the robot is developed. •A feedback and feedforward controller is presented to suppress machining vibration of the robot. -- Abstract: In the process of assembly and maintenance of ITER vacuum vessel (ITER VV), various machining tasks including threading, milling, welding-defects cutting and flexible hose boring are required to be performed from inside of ITER VV by on-site machining tools. Robot machine is a promising option for these tasks, but great chatter (machine vibration) would happen in the machining process. The chatter vibration will deteriorate the robot accuracy and surface quality, and even cause some damages on the end-effector tools and the robot structure itself. This paper introduces two vibration control methods, one is passive and another is active vibration control. For the passive vibration control, a parallel mechanism is presented to increase the stiffness of robot machine; for the active vibration control, a hybrid control method combining feedforward controller and nonlinear feedback controller is introduced for chatter suppression. A dynamic model and its chatter vibration phenomena of a hybrid robot is demonstrated. Simulation results are given based on the proposed hybrid robot machine which is developed for the ITER VV assembly and maintenance

  7. ITER ITA newsletter. No. 7, August 2003

    International Nuclear Information System (INIS)

    2003-10-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related meetings including the ninth meeting of the ITER Negotiators' Standing Sub-Group (NSSG-9), which was held on 28 and 29 July 2003 at Mita International Conference Center in Tokyo and the Confinement Database and Modelling (CDB and M) and Transport and Internal Transport Barrier (T and ITB) Topical Groups (TGs) joint meeting, which was held in St. Petersburg, Russia from 8 to 12 April 2003 and about retirement of Boris Kuvshinnikov, senior information officer, after 13 years at the ITER office Vienna

  8. ITER EDA newsletter. V. 10, no. 5

    International Nuclear Information System (INIS)

    2001-05-01

    This issue of the ITER EDA Newsletter includes a review of the International Symposium 'ITER days in Moscow' and Canada's bid to host ITER at the Clarington site. In connection with the successful completion of the Engineering Design of the International Thermonuclear Reactor (ITER) and the 50th anniversary of fusion research in the USSR, the Ministry of the Russian Federation for Atomic Energy (Minatom) with the participation of the Russian Academy of Sciences, organized the International Symposium 'ITER days in Moscow' on 7-8 June 2001

  9. ITER EDA newsletter. V. 3, no. 2

    International Nuclear Information System (INIS)

    1994-02-01

    This issue of the ITER EDA (Engineering Design Activities) Newsletter contains reports on the Fifth ITER Council Meeting held in Garching, Germany, 27-28 January 1994, a visit (28 January 1994) of an international group of Harvard Fellows to the San Diego Joint Work Site, the Inauguration Ceremony of the EC-hosted ITER joint work site in Garching (28 January 1994), on an ITER Technical Meeting on Assembly and Maintenance held in Garching, Germany, January 19-26, 1994, and a report on a Technical Committee Meeting on radiation effects on in-vessel components held in Garching, Germany, November 15-19, 1993, as well as an ITER Status Report

  10. ITER CTA newsletter. No. 16, January 2003

    International Nuclear Information System (INIS)

    2003-04-01

    This ITER CTA newsletter contains information about some ITER related activities including ITER transitional arrangements (ITA) which will start on 1 January 2003, the USA rejoining ITER and People's Republic of China joining ITER, the visit of Mr. J. Koizumi, Prime Minister of Japan, to Kurchatov Institute, Moscow, Russian Federation on 11 January 2003, and the most recent meeting of the Scrape-Off Layer (SOL) and Divertor Physics Group of the International Tokamak Physics Activity (ITPA), which was held in Lausanne, Switzerland, on October 21-23, 2002 at the CRPP/EFL laboratory

  11. Follower-Centered Perspective on Feedback: Effects of Feedback Seeking on Identification and Feedback Environment

    OpenAIRE

    Gong, Zhenxing; Li, Miaomiao; Qi, Yaoyuan; Zhang, Na

    2017-01-01

    In the formation mechanism of the feedback environment, the existing research pays attention to external feedback sources and regards individuals as objects passively accepting feedback. Thus, the external source fails to realize the individuals’ need for feedback, and the feedback environment cannot provide them with useful information, leading to a feedback vacuum. The aim of this study is to examine the effect of feedback-seeking by different strategies on the supervisor-feedback environme...

  12. Optimization of Iter with Iter-89P scaling

    International Nuclear Information System (INIS)

    Johner, J.

    1991-10-01

    Ignition in the ITER baseline machine is studied in the frame of a 1/2-D model using the ITER-89P scaling of the energy confinement time. The required value of the enhancement factor f L with respect to the L-mode, allowing ignition with a total fusion power of 1100 MW, is found to be 1.9 at an optimum operating temperature of 11 keV. A sensitivity analysis shows that the critical f L =2 value can be exceeded with relatively small changes in the physical assumptions. It is concluded that the safety margin is not sufficient for this project. Optimization of a thermonuclear plasma in a tokamak is then performed with constraints of given maximum magnetic field B in the superconducting windings, given distance between the plasma and the maximum magnetic field point, imposed safety factor at the plasma edge, and given averaged neutron flux at the plasma surface. The minimum enhancement factor f L with respect to the L-mode, allowing ignition at a given value of the total fusion power P fus , is only a function of the torus aspect ratio A. Taking the ITER reference values for the above constraints, the required value of f L is practically independent of the aspect ratio but can be sensibly improved by increasing the total fusion power P fus . With P fus =1700 MW, a reasonable safety margin (f L ≅ 1.5) is obtained. Analytical expressions of the conditions resulting from the above optimization are also derived for an arbitrary monomial scaling of the energy confinement time, and shown to give excellent agreement with the numerical results

  13. ITER ITA newsletter No. 32, July 2006

    International Nuclear Information System (INIS)

    2006-07-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related activities. The ITER Parties, at their Ministerial Meeting in May 2006 in Brussels, initialled the draft text of the prospective Agreement on the Establishment of the ITER International Fusion Energy Organization for the Joint Implementation of the ITER Project as well as the draft text of the Agreement on the Privileges and Immunities of the ITER International Fusion Energy Organisation for the Joint Implementation of the ITER Project. The Parties have requested that the IAEA Director General serve as Depositary of the two aforementioned Agreements and that the IAEA establish a Trust Fund to Support Common Expenditures under the ITER Transitional Arrangements, pending entry into force of the prospective Agreement on the Establishment of the ITER International Fusion Energy Organization for the Joint Implementation of the ITER Project. At its June Meeting in Vienna, the IAEA Board of Governors approved these requests. There is also information about the Tenth Meeting of the International Tokamak Physics Activity (ITPA) Topical Group (TG) on Diagnostics was held at the Kurchatov Institute, Moscow, from 10-14 April 2006

  14. ITER EDA newsletter. V. 10, no. 1

    International Nuclear Information System (INIS)

    2001-01-01

    This article provides a summary of results of the ITER Physics Committee Meeting, which was held on 14 October 2000 at the ITER Garching Joint Work Site, Germany. The ITER Physics Committee is the body responsible for overseeing, through the seven specialized Expert Groups, the R and D activities contributed voluntarily by the ITER Parties. The Parties' Physics Designated Persons, the Chairs and Co-Chairs of ITER Physics Expert Groups and the JCT members involved attended the Meeting. As usual, the meeting was chaired by the ITER Director, Dr. R. Aymar, who reported on the status of the ITER EDA. Dr. Aymar described the steps being taken in preparing the ITER-FEAT Final Design Report (FDR), and further stated that the Report would be available in time to be of benefit to the Negotiations on the ITER Joint Implementation, expected to start around May 2001. All Parties recognize that the ITER Physics Expert Group structure has been useful in focusing the tokamak physics activity on the ITER-relevant issues and provides an efficient worldwide collaboration on confirming innovative solutions. The concept of an international workshop to be organized as a pre-meeting of each Expert Group meeting, in order to involve U.S. scientists in the discussion of generic tokamak physics issues, was introduced in 2000, with some success, and its goal should be pursued

  15. ITER on the road to fusion energy

    International Nuclear Information System (INIS)

    Ikeda, Kaname

    2010-01-01

    On 21 November 2006, the government representatives of China, the European Union, India, Japan, Korea, Russia and the United States firmly committed to building the International Thermonuclear Experimental Reactor (ITER) by signing the ITER Agreement. The ITER Organization, which was formally established on 24 October 2007 after ratification of the ITER Agreement in each Member country, is the outcome of a two-decade-long collaborative effort aimed at demonstrating the scientific and technical feasibility of fusion energy. Each ITER partner has established a Domestic Agency (DA) for the construction of ITER, and the ITER Organization, based in Cadarache, in Southern France, is growing at a steady pace. The total number of staff reached 398 people from more than 20 nations by the end of September 2009. ITER will be built largely (90%) through in-kind contribution by the seven Members. On site, the levelling of the 40 ha platform has been completed. The roadworks necessary for delivering the ITER components from Fos harbour, close to Marseille, to the site are in the final stage of completion. With the aim of obtaining First Plasma in 2018, a new reference schedule has been developed by the ITER Organization and the DAs. Rapid attainment of the ITER goals is critical to accelerate fusion development-a crucial issue today in a world of increasing competition for scarce resources.

  16. ITER on the road to fusion energy

    Science.gov (United States)

    Ikeda, Kaname

    2010-01-01

    On 21 November 2006, the government representatives of China, the European Union, India, Japan, Korea, Russia and the United States firmly committed to building the International Thermonuclear Experimental Reactor (ITER) [1] by signing the ITER Agreement. The ITER Organization, which was formally established on 24 October 2007 after ratification of the ITER Agreement in each Member country, is the outcome of a two-decade-long collaborative effort aimed at demonstrating the scientific and technical feasibility of fusion energy. Each ITER partner has established a Domestic Agency (DA) for the construction of ITER, and the ITER Organization, based in Cadarache, in Southern France, is growing at a steady pace. The total number of staff reached 398 people from more than 20 nations by the end of September 2009. ITER will be built largely (90%) through in-kind contribution by the seven Members. On site, the levelling of the 40 ha platform has been completed. The roadworks necessary for delivering the ITER components from Fos harbour, close to Marseille, to the site are in the final stage of completion. With the aim of obtaining First Plasma in 2018, a new reference schedule has been developed by the ITER Organization and the DAs. Rapid attainment of the ITER goals is critical to accelerate fusion development—a crucial issue today in a world of increasing competition for scarce resources.

  17. Distributed Tuning of Boundary Resources

    DEFF Research Database (Denmark)

    Eaton, Ben; Elaluf-Calderwood, Silvia; Sørensen, Carsten

    2015-01-01

    The digital age has seen the rise of service systems involving highly distributed, heterogeneous, and resource-integrating actors whose relationships are governed by shared institutional logics, standards, and digital technology. The cocreation of service within these service systems takes place...... in the context of a paradoxical tension between the logic of generative and democratic innovations and the logic of infrastructural control. Boundary resources play a critical role in managing the tension as a firm that owns the infrastructure can secure its control over the service system while independent...... firms can participate in the service system. In this study, we explore the evolution of boundary resources. Drawing on Pickering’s (1993) and Barrett et al.’s (2012) conceptualizations of tuning, the paper seeks to forward our understanding of how heterogeneous actors engage in the tuning of boundary...

  18. Computation of undulator tuning curves

    International Nuclear Information System (INIS)

    Dejus, Roger J.

    1997-01-01

    Computer codes for fast computation of on-axis brilliance tuning curves and flux tuning curves have been developed. They are valid for an ideal device (regular planar device or a helical device) using the Bessel function formalism. The effects of the particle beam emittance and the beam energy spread on the spectrum are taken into account. The applicability of the codes and the importance of magnetic field errors of real insertion devices are addressed. The validity of the codes has been experimentally verified at the APS and observed discrepancies are in agreement with predicted reduction of intensities due to magnetic field errors. The codes are distributed as part of the graphical user interface XOP (X-ray OPtics utilities), which simplifies execution and viewing of the results

  19. Tuning Properties in Silver Clusters

    KAUST Repository

    Joshi, Chakra Prasad

    2015-07-09

    The properties of Ag nanoclusters are not as well understood as those of their more precious Au cousins. However, a recent surge in the exploration of strategies to tune the physicochemical characteristics of Ag clusters addresses this imbalance, leading to new insights into their optical, luminescence, crystal habit, metal-core, ligand-shell and environmental properties. In this Perspective, we provide an overview of the latest strategies along with a brief introduction of the theoretical framework necessary to understand the properties of silver nanoclusters and the basis for their tuning. The advances in cluster research and the future prospects presented in this Perspective will eventually guide the next large systematic study of nanoclusters, resulting in a single collection of data similar to the periodic table of elements.

  20. ITER EDA newsletter. V. 1, no. 2

    International Nuclear Information System (INIS)

    1992-12-01

    This second issue of the ITER Newsletter during the EDA (Engineering Design Activities) reports on (i) the second ITER Council Meeting held in the Russian Research Centre (RRC) ''Kurchatov Institute'', Moscow, Russia, December 15-16, 1992, (ii) the opening ceremony of the ITER Council Office at the RRC, (iii) the first meeting of the ITER Management Advisory Committee (MAC), (iv) the start-up of the ITER EDA at Garching, Germany, (v) descriptions of the ITER Co-Centres at Naka, Japan, and (vi) San Diego, USA, (vii) contact persons activities, (viii) the adoption by the ITER Council of the recommendations by the Special Working Group 1 (SWG-1), (ix) news in brief, and (x) coming events

  1. Iterative optimization of xylose catabolism in Saccharomyces cerevisiae using combinatorial expression tuning.

    Science.gov (United States)

    Latimer, Luke N; Dueber, John E

    2017-06-01

    A common challenge in metabolic engineering is rapidly identifying rate-controlling enzymes in heterologous pathways for subsequent production improvement. We demonstrate a workflow to address this challenge and apply it to improving xylose utilization in Saccharomyces cerevisiae. For eight reactions required for conversion of xylose to ethanol, we screened enzymes for functional expression in S. cerevisiae, followed by a combinatorial expression analysis to achieve pathway flux balancing and identification of limiting enzymatic activities. In the next round of strain engineering, we increased the copy number of these limiting enzymes and again tested the eight-enzyme combinatorial expression library in this new background. This workflow yielded a strain that has a ∼70% increase in biomass yield and ∼240% increase in xylose utilization. Finally, we chromosomally integrated the expression library. This library enriched for strains with multiple integrations of the pathway, which likely were the result of tandem integrations mediated by promoter homology. Biotechnol. Bioeng. 2017;114: 1301-1309. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. Iterative tuning of feedforward IPC for two-bladed wind turbines

    NARCIS (Netherlands)

    Mulders, S.P.; van Solingen, E.; van Wingerden, J.W.; Beerens, J; Bossanyi, E.; Chaviaropoulos, T.; Cheng, P.W.

    2016-01-01

    At present, the cost of offshore wind energy does not meet the level of onshore wind and fossil-based energy sources. One way to extend the turbine lifetime, and thus reduce cost, is by reduction of the fatigue loads of blades and other turbine parts using Individual Pitch Control (IPC). This type

  3. An Iteration Scheme for Contraction Mappings with an Application to Synchronization of Discrete Logistic Maps

    Directory of Open Access Journals (Sweden)

    Ke Ding

    2017-01-01

    Full Text Available This paper deals with designing a new iteration scheme associated with a given scheme for contraction mappings. This new scheme has a similar structure to that of the given scheme, in which those two iterative schemes converge to the same fixed point of the given contraction mapping. The positive influence of feedback parameters on the convergence rate of this new scheme is investigated. Moreover, the derived convergence and comparison results can be extended to nonexpansive mappings. As an application, the derived results are utilized to study the synchronization of logistic maps. Two illustrated examples are used to reveal the effectiveness of our results.

  4. Eighth-Grade Violinists' Instrument Tuning Ability: A Comparison of Pitch Perception and Tuning Accuracy

    Science.gov (United States)

    Hopkins, Michael T.

    2015-01-01

    The purpose of this study was to explore the relationship between eighth-grade violinists' pitch perception and instrument tuning skill. The perceptual task was a researcher-developed computer-based Violin Tuning Perception Test. The instrument tuning task involved tuning two violins, one mistuned flat and the other mistuned sharp. Participants (N…

  5. RF feedback for KEKB

    Energy Technology Data Exchange (ETDEWEB)

    Ezura, Eizi; Yoshimoto, Shin-ichi; Akai, Kazunori [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1996-08-01

    This paper describes the present status of the RF feedback development for the KEK B-Factory (KEKB). A preliminary experiment concerning the RF feedback using a parallel comb-filter was performed through a choke-mode cavity and a klystron. The RF feedback has been tested using the beam of the TRISTAN Main Ring, and has proved to be effective in damping the beam instability. (author)

  6. Neural cryptography with feedback.

    Science.gov (United States)

    Ruttor, Andreas; Kinzel, Wolfgang; Shacham, Lanir; Kanter, Ido

    2004-04-01

    Neural cryptography is based on a competition between attractive and repulsive stochastic forces. A feedback mechanism is added to neural cryptography which increases the repulsive forces. Using numerical simulations and an analytic approach, the probability of a successful attack is calculated for different model parameters. Scaling laws are derived which show that feedback improves the security of the system. In addition, a network with feedback generates a pseudorandom bit sequence which can be used to encrypt and decrypt a secret message.

  7. Situated Formative Feedback

    DEFF Research Database (Denmark)

    Lukassen, Niels Bech; Wahl, Christian; Sorensen, Elsebeth Korsgaard

    This study addresses the conceptual challenge of providing students with good quality feedback to enhance student learning in an online community of practice (COP). The aim of the study is to identify feedback mechanisms in a virtual learning environment (VLE) and to create a full formative...... refer to this type of feedback as, Situated Formative Feedback (SFF). As a basis for exploring, identifying and discussing relevant aspects of SFF the paper analyses qualitative data from a Moodle dialogue. Data are embedded in the qualitative analytic program Nvivo and are analysed with a system...

  8. Feedback stabilization initiative

    International Nuclear Information System (INIS)

    1997-06-01

    Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes

  9. Feedback stabilization initiative

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-06-01

    Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes.

  10. Policy Feedback System (PFS)

    Data.gov (United States)

    Social Security Administration — The Policy Feedback System (PFS) is a web application developed by the Office of Disability Policy Management Information (ODPMI) team that gathers empirical data...

  11. ITER ITA newsletter. No. 20, February-March 2005

    International Nuclear Information System (INIS)

    2005-03-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related activities including interview on the occasion of Academician E.P. Velikhov' 70th birthday conducted by Dr. Lev Golubbchikov, former ITER Contact Person of the Russian Federation and a new document management system of ITER called IDM (ITER Document Management), which supersedes the old IDoMS

  12. Iterative near-term ecological forecasting: Needs, opportunities, and challenges

    Science.gov (United States)

    Dietze, Michael C.; Fox, Andrew; Beck-Johnson, Lindsay; Betancourt, Julio L.; Hooten, Mevin B.; Jarnevich, Catherine S.; Keitt, Timothy H.; Kenney, Melissa A.; Laney, Christine M.; Larsen, Laurel G.; Loescher, Henry W.; Lunch, Claire K.; Pijanowski, Bryan; Randerson, James T.; Read, Emily; Tredennick, Andrew T.; Vargas, Rodrigo; Weathers, Kathleen C.; White, Ethan P.

    2018-01-01

    Two foundational questions about sustainability are “How are ecosystems and the services they provide going to change in the future?” and “How do human decisions affect these trajectories?” Answering these questions requires an ability to forecast ecological processes. Unfortunately, most ecological forecasts focus on centennial-scale climate responses, therefore neither meeting the needs of near-term (daily to decadal) environmental decision-making nor allowing comparison of specific, quantitative predictions to new observational data, one of the strongest tests of scientific theory. Near-term forecasts provide the opportunity to iteratively cycle between performing analyses and updating predictions in light of new evidence. This iterative process of gaining feedback, building experience, and correcting models and methods is critical for improving forecasts. Iterative, near-term forecasting will accelerate ecological research, make it more relevant to society, and inform sustainable decision-making under high uncertainty and adaptive management. Here, we identify the immediate scientific and societal needs, opportunities, and challenges for iterative near-term ecological forecasting. Over the past decade, data volume, variety, and accessibility have greatly increased, but challenges remain in interoperability, latency, and uncertainty quantification. Similarly, ecologists have made considerable advances in applying computational, informatic, and statistical methods, but opportunities exist for improving forecast-specific theory, methods, and cyberinfrastructure. Effective forecasting will also require changes in scientific training, culture, and institutions. The need to start forecasting is now; the time for making ecology more predictive is here, and learning by doing is the fastest route to drive the science forward.

  13. Oracle SQL tuning with Oracle SQLTXPLAIN

    CERN Document Server

    Charalambides, Stelios

    2013-01-01

    Oracle SQL Tuning with SQLTXPLAIN is a practical guide to SQL tuning the way Oracle's own experts do it, using a freely downloadable tool called SQLTXPLAIN. Using this simple tool you'll learn how to tune even the most complex SQL, and you'll learn to do it quickly, without the huge learning curve usually associated with tuning as a whole.  Firmly based in real world problems, this book helps you reclaim system resources and avoid the most common bottleneck in overall performance, badly tuned SQL.  You'll learn how the optimizer works, how to take advantage of its latest features, and when it'

  14. What Are Our International Students Telling Us? Further Explorations of a Formative Feedback Intervention, to Support Academic Literacy

    Science.gov (United States)

    Burns, Caroline; Foo, Martin

    2014-01-01

    This study reports on a further iteration of an action research cycle, discussed in Burns and Foo (2012, 2013). It explores how formative feedback on academic literacy was used and acted upon, and if a Formative Feedback Intervention (FFI) increased the students' confidence in future assignments. It also considers whether the assignment of a grade…

  15. Cryogenic instrumentation for ITER magnets

    Science.gov (United States)

    Poncet, J.-M.; Manzagol, J.; Attard, A.; André, J.; Bizel-Bizellot, L.; Bonnay, P.; Ercolani, E.; Luchier, N.; Girard, A.; Clayton, N.; Devred, A.; Huygen, S.; Journeaux, J.-Y.

    2017-02-01

    Accurate measurements of the helium flowrate and of the temperature of the ITER magnets is of fundamental importance to make sure that the magnets operate under well controlled and reliable conditions, and to allow suitable helium flow distribution in the magnets through the helium piping. Therefore, the temperature and flow rate measurements shall be reliable and accurate. In this paper, we present the thermometric chains as well as the venturi flow meters installed in the ITER magnets and their helium piping. The presented thermometric block design is based on the design developed by CERN for the LHC, which has been further optimized via thermal simulations carried out by CEA. The electronic part of the thermometric chain was entirely developed by the CEA and will be presented in detail: it is based on a lock-in measurement and small signal amplification, and also provides a web interface and software to an industrial PLC. This measuring device provides a reliable, accurate, electromagnetically immune, and fast (up to 100 Hz bandwidth) system for resistive temperature sensors between a few ohms to 100 kΩ. The flowmeters (venturi type) which make up part of the helium mass flow measurement chain have been completely designed, and manufacturing is on-going. The behaviour of the helium gas has been studied in detailed thanks to ANSYS CFX software in order to obtain the same differential pressure for all types of flowmeters. Measurement uncertainties have been estimated and the influence of input parameters has been studied. Mechanical calculations have been performed to guarantee the mechanical strength of the venturis required for pressure equipment operating in nuclear environment. In order to complete the helium mass flow measurement chain, different technologies of absolute and differential pressure sensors have been tested in an applied magnetic field to identify equipment compatible with the ITER environment.

  16. Remote handling maintenance of ITER

    International Nuclear Information System (INIS)

    Haange, R.

    1999-01-01

    The remote maintenance strategy and the associated component design of the International Thermonuclear Experimental Reactor (ITER) have reached a high degree of completeness, especially with respect to those components that are expected to require frequent or occasional remote maintenance. Large-scale test stands, to demonstrate the principle feasibility of the remote maintenance procedures and to develop the required equipment and tools, were operational at the end of the Engineering Design Activities (EDA) phase. The initial results are highly encouraging: major remote equipment deployment and component replacement operations have been successfully demonstrated. (author)

  17. ITER fuel cycle systems layout

    International Nuclear Information System (INIS)

    Kveton, O.K.

    1990-10-01

    The ITER fuel cycle building (FCB) will contain the following systems: fuel purification - permeator based; fuel purification - molecular sieves; impurity treatment; waste water storage and treatment; isotope separation; waste water tritium extraction; tritium extraction from solid breeder; tritium extraction from test modules; tritium storage, shipping and receiving; tritium laboratory; atmosphere detritiation systems; fuel cycle control centre; tritiated equipment maintenance space; control maintenance space; health physics laboratory; access, access control and facilities. The layout of the FCB and the requirements for these systems are described. (10 figs.)

  18. Distributed Video Coding: Iterative Improvements

    DEFF Research Database (Denmark)

    Luong, Huynh Van

    at the decoder side offering such benefits for these applications. Although there have been some advanced improvement techniques, improving the DVC coding efficiency is still challenging. The thesis addresses this challenge by proposing several iterative algorithms at different working levels, e.g. bitplane...... and noise modeling and also learn from the previous decoded Wyner-Ziv (WZ) frames, side information and noise learning (SING) is proposed. The SING scheme introduces an optical flow technique to compensate the weaknesses of the block based SI generation and also utilizes clustering of DCT blocks to capture...

  19. The physics role of ITER

    International Nuclear Information System (INIS)

    Rutherford, P.H.

    1997-04-01

    Experimental research on the International Thermonuclear Experimental Reactor (ITER) will go far beyond what is possible on present-day tokamaks to address new and challenging issues in the physics of reactor-like plasmas. First and foremost, experiments in ITER will explore the physics issues of burning plasmas--plasmas that are dominantly self-heated by alpha-particles created by the fusion reactions themselves. Such issues will include (i) new plasma-physical effects introduced by the presence within the plasma of an intense population of energetic alpha particles; (ii) the physics of magnetic confinement for a burning plasma, which will involve a complex interplay of transport, stability and an internal self-generated heat source; and (iii) the physics of very-long-pulse/steady-state burning plasmas, in which much of the plasma current is also self-generated and which will require effective control of plasma purity and plasma-wall interactions. Achieving and sustaining burning plasma regimes in a tokamak necessarily requires plasmas that are larger than those in present experiments and have higher energy content and power flow, as well as much longer pulse length. Accordingly, the experimental program on ITER will embrace the study of issues of plasma physics and plasma-materials interactions that are specific to a reactor-scale fusion experiment. Such issues will include (i) confinement physics for a tokamak in which, for the first time, the core-plasma and the edge-plasma are simultaneously in a reactor-like regime; (ii) phenomena arising during plasma transients, including so-called disruptions, in regimes of high plasma current and thermal energy; and (iii) physics of a radiative divertor designed for handling high power flow for long pulses, including novel plasma and atomic-physics effects as well as materials science of surfaces subject to intense plasma interaction. Experiments on ITER will be conducted by researchers in control rooms situated at major

  20. New tuning method for PID controller.

    Science.gov (United States)

    Shen, Jing-Chung

    2002-10-01

    In this paper, a tuning method for proportional-integral-derivative (PID) controller and the performance assessment formulas for this method are proposed. This tuning method is based on a genetic algorithm based PID controller design method. For deriving the tuning formula, the genetic algorithm based design method is applied to design PID controllers for a variety of processes. The relationship between the controller parameters and the parameters that characterize the process dynamics are determined and the tuning formula is then derived. Using simulation studies, the rules for assessing the performance of a PID controller tuned by the proposed method are also given. This makes it possible to incorporate the capability to determine if the PID controller is well tuned or not into an autotuner. An autotuner based on this new tuning method and the corresponding performance assessment rules is also established. Simulations and real-time experimental results are given to demonstrate the effectiveness and usefulness of these formulas.

  1. IHadoop: Asynchronous iterations for MapReduce

    KAUST Repository

    Elnikety, Eslam Mohamed Ibrahim

    2011-11-01

    MapReduce is a distributed programming frame-work designed to ease the development of scalable data-intensive applications for large clusters of commodity machines. Most machine learning and data mining applications involve iterative computations over large datasets, such as the Web hyperlink structures and social network graphs. Yet, the MapReduce model does not efficiently support this important class of applications. The architecture of MapReduce, most critically its dataflow techniques and task scheduling, is completely unaware of the nature of iterative applications; tasks are scheduled according to a policy that optimizes the execution for a single iteration which wastes bandwidth, I/O, and CPU cycles when compared with an optimal execution for a consecutive set of iterations. This work presents iHadoop, a modified MapReduce model, and an associated implementation, optimized for iterative computations. The iHadoop model schedules iterations asynchronously. It connects the output of one iteration to the next, allowing both to process their data concurrently. iHadoop\\'s task scheduler exploits inter-iteration data locality by scheduling tasks that exhibit a producer/consumer relation on the same physical machine allowing a fast local data transfer. For those iterative applications that require satisfying certain criteria before termination, iHadoop runs the check concurrently during the execution of the subsequent iteration to further reduce the application\\'s latency. This paper also describes our implementation of the iHadoop model, and evaluates its performance against Hadoop, the widely used open source implementation of MapReduce. Experiments using different data analysis applications over real-world and synthetic datasets show that iHadoop performs better than Hadoop for iterative algorithms, reducing execution time of iterative applications by 25% on average. Furthermore, integrating iHadoop with HaLoop, a variant Hadoop implementation that caches

  2. A Tuning Approach for Oset-free MPC with Conditional Reference Adaptation

    DEFF Research Database (Denmark)

    Waschl, Harald; Jørgensen, John Bagterp; Huusom, Jakob Kjøbsted

    2014-01-01

    addresses the performance targets in the nominal case, decouples the system and essentially leads to a rst order response. The second outer loop enables oset-free tracking in case of unknown disturbances and consists of feedback controllers adapting the reference. Due to the mentioned properties...... these controllers can be tuned separate and by known guidelines. To address conditions with active input constraints, additionally a conditional reference adaptation scheme is introduced. The tuning strategy is evaluated on a simulated linear Wood-Berry binary distillation column example....

  3. Effects of feedback reliability on feedback-related brain activity: A feedback valuation account.

    Science.gov (United States)

    Ernst, Benjamin; Steinhauser, Marco

    2018-04-06

    Adaptive decision making relies on learning from feedback. Because feedback sometimes can be misleading, optimal learning requires that knowledge about the feedback's reliability be utilized to adjust feedback processing. Although previous research has shown that feedback reliability indeed influences feedback processing, the underlying mechanisms through which this is accomplished remain unclear. Here we propose that feedback processing is adjusted by the adaptive, top-down valuation of feedback. We assume that unreliable feedback is devalued relative to reliable feedback, thus reducing the reward prediction errors that underlie feedback-related brain activity and learning. A crucial prediction of this account is that the effects of feedback reliability are susceptible to contrast effects. That is, the effects of feedback reliability should be enhanced when both reliable and unreliable feedback are experienced within the same context, as compared to when only one level of feedback reliability is experienced. To evaluate this prediction, we measured the event-related potentials elicited by feedback in two experiments in which feedback reliability was varied either within or between blocks. We found that the fronto-central valence effect, a correlate of reward prediction errors during reinforcement learning, was reduced for unreliable feedback. But this result was obtained only when feedback reliability was varied within blocks, thus indicating a contrast effect. This suggests that the adaptive valuation of feedback is one mechanism underlying the effects of feedback reliability on feedback processing.

  4. The ITER divertor cassette project

    International Nuclear Information System (INIS)

    Ulrickson, M.; Tivey, R.; Akiba, M.

    1999-01-01

    The divertor 'Large Project' was conceived with the aim of demonstrating the feasibility of meeting the lifetime requirements by employing the candidate armor materials of beryllium, tungsten (W) and carbon-fiber-composite (CFC). At the start, there existed only limited experience with constructing water-cooled high heat flux armored components for tokamaks. To this was added the complication posed by the need to use a silver-free joining technique that avoids the transmutation of n-irradiated silver to cadmium. The research project involving the four Home Teams (HTs) has focused on the design, development, manufacture and testing of full-scale Plasma Facing Components (PFCs) suitable for ITER. The task addressed all the issues facing ITER divertor design, such as providing adequate armor erosion lifetime, meeting the required armor-heat sink joint lifetime and heat sink fatigue life, sustaining thermal-hydraulic and electromechanical loads, and seeking to identify the most cost-effective manufacturing options. This paper will report the results of the divertor large project. (author)

  5. The ITER divertor cassette project

    International Nuclear Information System (INIS)

    Ulrickson, M.; Tivey, R.; Akiba, M.

    2001-01-01

    The divertor ''Large Project'' was conceived with the aim of demonstrating the feasibility of meeting the lifetime requirements by employing the candidate armor materials of beryllium, tungsten (W) and carbon-fiber-composite (CFC). At the start, there existed only limited experience with constructing water-cooled high heat flux armored components for tokamaks. To this was added the complication posed by the need to use a silver-free joining technique that avoids the transmutation of n-irradiated silver to cadmium. The research project involving the four Home Teams (HTs) has focused on the design, development, manufacture and testing of full-scale Plasma Facing Components (PFCs) suitable for ITER. The task addressed all the issues facing ITER divertor design, such as providing adequate armor erosion lifetime, meeting the required armor-heat sink joint lifetime and heat sink fatigue life, sustaining thermal-hydraulic and electromechanical loads, and seeking to identify the most cost-effective manufacturing options. This paper will report the results of the divertor large project. (author)

  6. ITER Port Interspace Pressure Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Carbajo, Juan J [ORNL; Van Hove, Walter A [ORNL

    2016-01-01

    The ITER Vacuum Vessel (VV) is equipped with 54 access ports. Each of these ports has an opening in the bioshield that communicates with a dedicated port cell. During Tokamak operation, the bioshield opening must be closed with a concrete plug to shield the radiation coming from the plasma. This port plug separates the port cell into a Port Interspace (between VV closure lid and Port Plug) on the inner side and the Port Cell on the outer side. This paper presents calculations of pressures and temperatures in the ITER (Ref. 1) Port Interspace after a double-ended guillotine break (DEGB) of a pipe of the Tokamak Cooling Water System (TCWS) with high temperature water. It is assumed that this DEGB occurs during the worst possible conditions, which are during water baking operation, with water at a temperature of 523 K (250 C) and at a pressure of 4.4 MPa. These conditions are more severe than during normal Tokamak operation, with the water at 398 K (125 C) and 2 MPa. Two computer codes are employed in these calculations: RELAP5-3D Version 4.2.1 (Ref. 2) to calculate the blowdown releases from the pipe break, and MELCOR, Version 1.8.6 (Ref. 3) to calculate the pressures and temperatures in the Port Interspace. A sensitivity study has been performed to optimize some flow areas.

  7. RAMI analysis of ITER CODAC

    International Nuclear Information System (INIS)

    Kitazawa, Sin-iti; Okayama, Katsumi; Neyatani, Yuzuru; Sagot, Francois; Houtte, Didier van; Abadie, Lana; Yonekawa, Izuru; Wallander, Anders; Klotz, Wolf-Dieter

    2012-01-01

    In the ITER project, Reliability, Availability, Maintainability and Inspectability (RAMI) approach has been adopted for technical risk control to guide the design of components and the preparation for operation and maintenance. RAMI analysis of the ITER CODAC System, the central plant control system, was performed in the current design available in the conceptual design phase. A functional breakdown was prepared, resulting in the system being divided into 5 main functions themselves divided into sub-functions. The Failure Modes, Effects and Critical Analysis were performed to initiate risk mitigation actions. Criticality matrices highlight the risks of the different failure modes with regard to their probability of occurrence and the impact on the availability. Identified risks exist on the effect on data storage hardware and for computer software. Reliability block diagrams were prepared to estimate the reliability and availability of each function under stipulated operating conditions. The inherent availability of the mandatory functions for the control of plasma experiments with mitigations was calculated to be 99.2% that is higher than the project required value of 98.8%. Compensating provisions are advocated in terms of design, testing, operation procedure and maintenance requirements in order to reduce risk levels.

  8. Feedback For Helpers

    Science.gov (United States)

    Stromer, Walter F.

    1975-01-01

    The author offers some feedback to those in the helping professions in three areas: (1) forms and letters; (2) jumping to conclusions; and (3) blaming and belittling, in hopes of stimulating more feedback as well as more positive ways of performing their services. (HMV)

  9. Feedback og interpersonel kommunikation

    DEFF Research Database (Denmark)

    Dindler, Camilla

    2016-01-01

    Som interpersonel kommunikationsform handler feedback om at observere, mærke og italesætte det, som handler om relationen mellem samtaleparterne mere end om samtaleemnet. Her er fokus på, hvad der siges og hvordan der kommunikeres sammen. Feedback er her ikke en korrigerende tilbagemelding til...

  10. Existence test for asynchronous interval iterations

    DEFF Research Database (Denmark)

    Madsen, Kaj; Caprani, O.; Stauning, Ole

    1997-01-01

    In the search for regions that contain fixed points ofa real function of several variables, tests based on interval calculationscan be used to establish existence ornon-existence of fixed points in regions that are examined in the course ofthe search. The search can e.g. be performed...... as a synchronous (sequential) interval iteration:In each iteration step all components of the iterate are calculatedbased on the previous iterate. In this case it is straight forward to base simple interval existence and non-existencetests on the calculations done in each step of the iteration. The search can also...... on thecomponentwise calculations done in the course of the iteration. These componentwisetests are useful for parallel implementation of the search, sincethe tests can then be performed local to each processor and only when a test issuccessful do a processor communicate this result to other processors....

  11. Feedback i matematik

    DEFF Research Database (Denmark)

    Sortkær, Bent

    2017-01-01

    Feedback bliver i litteraturen igen og igen fremhævet som et af de mest effektive midler til at fremme elevers præstationer i skolen (Hartberg, Dobson, & Gran, 2012; Hattie & Timperley, 2007; Wiliam, 2015). Dette på trods af, at flere forskere påpeger, at feedback ikke altid er læringsfremmende...... (Hattie & Gan, 2011), og nogle endda viser, at feedback kan have en negativ virkning i forhold til præstationer (Kluger & DeNisi, 1996). Artiklen vil undersøge disse tilsyneladende modstridende resultater ved at stille spørgsmålet: Under hvilke forudsætninger virker feedback i matematik læringsfremmende......? Dette gøres ved at dykke ned i forskningslitteraturen omhandlende feedback ud fra en række temaer for på den måde at besvare ovenstående spørgsmål....

  12. Feedback and Incentives:

    DEFF Research Database (Denmark)

    Eriksson, Tor Viking; Poulsen, Anders; Villeval, Marie-Claire

    This paper experimentally investigates the impact of different pay and relative performance information policies on employee effort. We explore three information policies: No feedback about relative performance, feedback given halfway through the production period, and continuously updated feedback....... The pay schemes are a piece rate payment scheme and a winner-takes-all tournament. We find that, regardless of the pay scheme used, feedback does not improve performance. There are no significant peer effects in the piece-rate pay scheme. In contrast, in the tournament scheme we find some evidence...... of positive peer effects since the underdogs almost never quit the competition even when lagging significantly behind, and frontrunners do not slack off. Moreover, in both pay schemes information feedback reduces the quality of the low performers' work....

  13. ITER EDA newsletter. V. 2, no. 10

    International Nuclear Information System (INIS)

    1993-10-01

    This issue of the ITER EDA (Engineering Design Activities) Newsletter contains progress reports on the Fourth ITER Council Meeting in San Diego, 29 September - 1 October 1993, on the Third Meeting of the ITER Management Advisory Committee (MAC) in Naka, Japan, 16-17 September 1993, and on the flag raising ceremony at the US hosted joint work site in San Diego, California, 1 October 1993

  14. On One-Point Iterations and DIIS

    DEFF Research Database (Denmark)

    Østerby, Ole; Sørensen, Hans Henrik Brandenborg

    2009-01-01

    We analyze various iteration procedures in many dimensions inspired by the SCF iteration used in first principles electronic structure calculations. We show that the simple mixing of densities can turn a divergent (or slowly convergent) iteration into a (faster) convergent process provided all th...... occur if the residual vectors are (nearly) linearly dependent. We show how to remove this linear dependence using the singular value decomposition (SVD)....

  15. ITER ITA newsletter. No. 19, January 2005

    International Nuclear Information System (INIS)

    2005-02-01

    This issue of the ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related meetings, namely, the 20th IAEA Fusion Energy Conference, which was held on 1-6 November 2004 in Vilamoura, Portugal and the seventh meeting of the ITPA topical group on diagnostics which was held at the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), Hefei, P. R. China, from 11-15 October 2004

  16. Iterative Splitting Methods for Differential Equations

    CERN Document Server

    Geiser, Juergen

    2011-01-01

    Iterative Splitting Methods for Differential Equations explains how to solve evolution equations via novel iterative-based splitting methods that efficiently use computational and memory resources. It focuses on systems of parabolic and hyperbolic equations, including convection-diffusion-reaction equations, heat equations, and wave equations. In the theoretical part of the book, the author discusses the main theorems and results of the stability and consistency analysis for ordinary differential equations. He then presents extensions of the iterative splitting methods to partial differential

  17. ITER EDA Newsletter. V. 6, no. 9

    International Nuclear Information System (INIS)

    1997-09-01

    This issue of the Newsletter reports on new ITER Home Page and contains a report on the combined workshop of the ITER confinement and transport expert group and of the confinement modeling and database expert group, by D. Boucher, V. Mukhavatov (both ITER JCT), J.G. Cordey, JET Joint Undertaking , M. Wakatani, Kyoto University held at the Max-Planck-Institut for Plasmaphysik, Garching, Germany on September 25 - 30 1997

  18. ITER EDA Newsletter. V. 2, no. 3

    International Nuclear Information System (INIS)

    1993-03-01

    This ITER EDA (Engineering Design Activities) Newsletter issue includes a description of the ITER Joint Central Team's management, the ITER Management System and supporting software progress, activities of the Special Working Group 2, a brief summary of a technical meeting on the experimental approach to the physics of the high density divertor, a summary on the status of the International Fusion Evaluated Nuclear Data Library (FENDL), and an obituary on Dr. Henry Seligman (IAEA)

  19. ITER EDA Newsletter. V.2, no.5

    International Nuclear Information System (INIS)

    1993-05-01

    This ITER EDA (Engineering Design Activities), Newsletter issue includes reports on the third ITER council meeting in Tokyo on the involvement of other countries, on an outline of the report by the Management Advisory Committee (MAC), on such involvement, and on the improvement by the MAC and the ITER Council to proceed with Task Agreements on the Research and Development programme of the Superconductor Coils and Structures Division

  20. Preconditioned iterations to calculate extreme eigenvalues

    Energy Technology Data Exchange (ETDEWEB)

    Brand, C.W.; Petrova, S. [Institut fuer Angewandte Mathematik, Leoben (Austria)

    1994-12-31

    Common iterative algorithms to calculate a few extreme eigenvalues of a large, sparse matrix are Lanczos methods or power iterations. They converge at a rate proportional to the separation of the extreme eigenvalues from the rest of the spectrum. Appropriate preconditioning improves the separation of the eigenvalues. Davidson`s method and its generalizations exploit this fact. The authors examine a preconditioned iteration that resembles a truncated version of Davidson`s method with a different preconditioning strategy.

  1. Performance and LHC beam stability issue related to Q/Q' diagnostics and feedback systems

    CERN Document Server

    Steinhagen, Ralph J

    2010-01-01

    The baseline tune (Q) and chromaticity (Q’) diagnostics and associated feedback systems played a crucial role during the LHC commissioning, in establishing circulating beam, the first ramps and their fill-to-fill feed-forward correction. Early on, they also allowed to identify issues such as the residual tune stability, beam spectrum interferences and beam-beam effects – all of which may impact beam lifetimes and thus need to be addressed in view of nominal LHC operation.

  2. Hearing aid fine-tuning based on Dutch descriptions.

    Science.gov (United States)

    Thielemans, Thijs; Pans, Donné; Chenault, Michelene; Anteunis, Lucien

    2017-07-01

    The aim of this study was to derive an independent fitting assistant based on expert consensus. Two questions were asked: (1) what (Dutch) terms do hearing impaired listeners use nowadays to describe their specific hearing aid fitting problems? (2) What is the expert consensus on how to resolve these complaints by adjusting hearing aid parameters? Hearing aid dispensers provided descriptors that impaired listeners use to describe their reactions to specific hearing aid fitting problems. Hearing aid fitting experts were asked "How would you adjust the hearing aid if its user reports that the aid sounds…?" with the blank filled with each of the 40 most frequently mentioned descriptors. 112 hearing aid dispensers and 15 hearing aid experts. The expert solution with the highest weight value was considered the best solution for that descriptor. Principal component analysis (PCA) was performed to identify a factor structure in fitting problems. Nine fitting problems could be identified resulting in an expert-based, hearing aid manufacturer independent, fine-tuning fitting assistant for clinical use. The construction of an expert-based, hearing aid manufacturer independent, fine-tuning fitting assistant to be used as an additional tool in the iterative fitting process is feasible.

  3. ITER EDA Newsletter. V. 3, no. 10

    International Nuclear Information System (INIS)

    1994-10-01

    This ITER EDA (Engineering Design Activities) Newsletter issue reports on (i) the ITER-relevant statements made at the occasion of the 15th IAEA fusion conference in Seville, Spain, September 26 - October 1, 1994; (ii) a comprehensive technical presentation of the ITER EDA developments at the same conference; (iii) the first Workshop of the ITER Expert Group on Confinement and Transport, held at the San Diego Joint Work Site on 22-25 August 1994; and (iv) the visit to the San Diego Work Site of the representatives of a local philanthropic group, the ARCS Foundation (Achievement Rewards for College Scientists)

  4. ITER ITA newsletter. No. 23, June 2005

    International Nuclear Information System (INIS)

    2005-06-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related meeting the Eighth Meeting of the ITPA Topical Group (TG) on Diagnostics was held at the Culham Science Centre, UKAEA, from 14-18 March 2005 and the Third International Atomic Energy Agency - Technical Meeting (TM) on Electron Cyclotron Resonance Heating (ECRH) in ITER, following those in Oharai, Japan in 1999, and in Kloster Seeon, Germany in 2003, was held in Como, Italy, from May 2 to May 5, 2005, in a two-and-half day intense workshop

  5. ITER EDA newsletter. V. 5, no. 6

    International Nuclear Information System (INIS)

    1996-06-01

    This issue of the ITER Engineering Design Activities Newsletter contains a report on the Tenth Meeting of the ITER Technical Advisory Committee; on the papers relevant to the ITER project that were presented during the 12th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices held at St. Raphael, France, on 20-24 May 1996; and a note on the interrelationship between ITER and the PSI Conference, initiated more than twenty years ago by surface and solid-state physicists

  6. ITER EDA newsletter. V. 10, no. 2

    International Nuclear Information System (INIS)

    2001-02-01

    In 2000, the Fusion Power Associates Awards were given, among others, to persons closely associated with the developments of ITER. These Awards are given annually for Distinguished Career, for Leadership, and for Excellence in Fusion Engineering. Distinguished Career Award to Ken Tomabechi, a leading fusion researcher and director of the Japan Atomic Energy Research Institute. Leadership Award to: Robert Aymar, a leading European fusion researcher and has been ITER Director since 1994. Excellence in Fusion Engineering to: Gianfrano Federici, a staff member of the ITER Joint Central Team, working at the ITER Joint Work Site at Garching, Germany

  7. ITER EDA Newsletter. V. 3, no. 9

    International Nuclear Information System (INIS)

    1994-09-01

    This ITER EDA (Engineering Design Activities) Newsletter issue contains a description of the ITER Physics Research and Development (F.Perkins), a report on the first meeting of the ITER Divertor Physics and Divertor Modelling and Database Expert Groups (D. Post, G. Janeschitz, R. Stambaugh, M. Shimada), a report on the first meeting of the ITER Physics Expert Group on Diagnostics (A.E. Costley and K.M. Young), and a contribution entitled ''to meet or not to meet? If yes, for how long?'' (L. Golubchikov)

  8. First formal ITER negotiations make excellent progress

    International Nuclear Information System (INIS)

    Barnard, P.

    2001-01-01

    November 8 and 9 2001 marked the historic beginning of formal negotiations meetings on the ITER project. Delegations from Canada, the European Union, Japan and the Russian Federation met in Toronto, Canada, for the first in a series of Negotiations that is expected to lead, by the end of 2002, to an agreement on the joint implementation of ITER. This agreement will govern, under international law, the construction, operation and decommissioning of ITER. The Negotiations concluded by issuing a joint news release, reflecting a commitment to share the progress reports on the efforts to implement ITER

  9. Iterative solution of the reduced eigenvalue problem

    International Nuclear Information System (INIS)

    Sauer, G.

    1991-01-01

    The Guyan method of reducing the stiffness and mass matrices of large linear structures introduces errors in the reduced mass matrix. These errors cannot be completely avoided even if the analysis coordinates are chosen optimally. However, they can be elimiated by iterating on the eigenvectors found from the Guyan reduced matrices. The necessary iteration steps follow directly from the eigenvalue problem. The resulting iteration procedures are presented and applied to two test problems showing that the iterations enable the exact eigensolutions to be extracted. All errors from the Guyan reduced matrices are removed or substantially decreased. (orig.)

  10. ITER EDA newsletter. V. 5, no. 12

    International Nuclear Information System (INIS)

    1996-12-01

    This issue of the newsletter on the Engineering Design Activities (EDA) for the ITER Tokamak project contains a report on the Eleventh ITER Council Meeting held on December 17-18, 1996 in Tokyo, Japan; a report on the Eleventh Meeting of the ITER Technical Advisory Committee (TAC-11) Meeting held 3-7 December, 1996, at the ITER Naka Joint Work Site, Japan; and a report on the Fifth Workshop of the Confinement Modelling and Database Expert Group held in Montreal, Canada, October 13-16, 1996

  11. Feedback Valence Affects Auditory Perceptual Learning Independently of Feedback Probability

    OpenAIRE

    Amitay, Sygal; Moore, David R.; Molloy, Katharine; Halliday, Lorna F.

    2015-01-01

    Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they wer...

  12. Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

    International Nuclear Information System (INIS)

    Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N.

    2014-01-01

    In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ–ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed

  13. Research at ITER towards DEMO: Specific reactor diagnostic studies to be carried out on ITER

    Energy Technology Data Exchange (ETDEWEB)

    Krasilnikov, A. V.; Kaschuck, Y. A.; Vershkov, V. A.; Petrov, A. A.; Petrov, V. G.; Tugarinov, S. N. [Institution Project center ITER, Moscow (Russian Federation)

    2014-08-21

    In ITER diagnostics will operate in the very hard radiation environment of fusion reactor. Extensive technology studies are carried out during development of the ITER diagnostics and procedures of their calibration and remote handling. Results of these studies and practical application of the developed diagnostics on ITER will provide the direct input to DEMO diagnostic development. The list of DEMO measurement requirements and diagnostics will be determined during ITER experiments on the bases of ITER plasma physics results and success of particular diagnostic application in reactor-like ITER plasma. Majority of ITER diagnostic already passed the conceptual design phase and represent the state of the art in fusion plasma diagnostic development. The number of related to DEMO results of ITER diagnostic studies such as design and prototype manufacture of: neutron and γ–ray diagnostics, neutral particle analyzers, optical spectroscopy including first mirror protection and cleaning technics, reflectometry, refractometry, tritium retention measurements etc. are discussed.

  14. Feedback - fra et elevperspektiv

    DEFF Research Database (Denmark)

    Petersen, Benedikte Vilslev; Pedersen, Bent Sortkær

    Feedback bliver i litteraturen igen og igen fremhævet som et af de mest effektive midler til at fremme elevers præstationer i skolen (Hattie og Timperley, 2007). Andre studier er dog inde på at feedback ikke altid er læringsfremmende og nogle viser endda at feedback kan have en negativ virkning i...... forhold til præstationer (Kluger & DeNisi, 1996). I forsøget på at forklare hvordan og hvorfor feedback virker (forskelligt), er der undersøgt flere dimensioner og forhold omkring feedback (se bl.a. Black og Wiliam, 1998; Hattie og Timperley, 2007; Shute, 2008). Dog er der få studier der undersøger...... hvordan feedback opleves fra et elevperspektiv (Ruiz-Primo og Li, 2013). Samtidig er der i feedbacklitteraturen en mangel på kvalitative studier, der kommer tæt på fænomenet feedback, som det viser sig i klasserummet (Ruiz-Primo og Li, 2013) i naturlige omgivelser (Black og Wiliam, 1998), og hvordan...

  15. Feedback Loop Gains and Feedback Behavior (1996)

    DEFF Research Database (Denmark)

    Kampmann, Christian Erik

    2012-01-01

    elasticities. For illustration, the method is applied to a well-known system: the simple long-wave model. Because this model exhibits highly nonlinear behavior, it sheds light on the usefulness of linear methods to nonlinear system. The analysis leads to a more thorough and deeper understanding of the system......Linking feedback loops and system behavior is part of the foundation of system dynamics, yet the lack of formal tools has so far prevented a systematic application of the concept, except for very simple systems. Having such tools at their disposal would be a great help to analysts in understanding...... large, complicated simulation models. The paper applies tools from graph theory formally linking individual feedback loop strengths to the system eigenvalues. The significance of a link or a loop gain and an eigenvalue can be expressed in the eigenvalue elasticity, i.e., the relative change...

  16. Training effectiveness feedback

    International Nuclear Information System (INIS)

    Wiggin, N.A.

    1987-01-01

    A formal method of getting feedback about the job performance of employees is a necessary part of all the authors training programs. The formal process may prove to be inadequate if it is the only process in use. There are many ways and many opportunities to get good feedback about employee performance. It is important to document these methods and specific instances to supplement the more formalized process. The key is to identify them, encourage them, use them, and document the training actions that result from them. This paper describes one plant's method of getting feedback about performance of technicians in the field

  17. Brugbar peer feedback

    DEFF Research Database (Denmark)

    Hvass, Helle; Heger, Stine

    Studerende kan være medskabere af undervisning i akademisk skrivning, når de modtager og giver feedback til hinandens ufærdige akademiske tekster. Det ser vi i et udviklingsprojekt, hvor vi afprøver kollektive vejledningsformater. Vi har dog erfaret: 1. at studerende mangler træning i at give og ...... modtage feedback 2. at den manglende træning kan stå i vejen for realiseringen af læringspotentialet ved peer feedback....

  18. An autoethnographic exploration of the use of goal oriented feedback to enhance brief clinical teaching encounters.

    Science.gov (United States)

    Farrell, Laura; Bourgeois-Law, Gisele; Ajjawi, Rola; Regehr, Glenn

    2017-03-01

    Supervision in the outpatient context is increasingly in the form of single day interactions between students and preceptors. This creates difficulties for effective feedback, which often depends on a strong relationship of trust between preceptor and student. Building on feedback theories focusing on the relational and dialogic aspects of feedback, this study explored the use of goal-oriented feedback in brief encounters with learners. This study used autoethnography to explore one preceptor's feedback interactions over an eight-month period both in the ambulatory setting and on the wards. Data included written narrative reflections on feedback interactions with twenty-three learners informed by discussions with colleagues and repeated reading of feedback literature. Thematic and narrative analyses of data were performed iteratively. Data analysis emphasized four recurrent themes. (1) Goal discussions were most effective when initiated early and integrated throughout the learning experience. (2) Both learner and preceptor goals were multiple and varied, and feedback needed to reflect this complexity. (3) Negotiation or co-construction of goals was important when considering the focus of feedback discussions in order to create safer, more effective interactions. (4) Goal oriented interactions offer potential benefits to the learner and preceptor. Goal oriented feedback promotes dialogue as it requires both preceptor and learner to acknowledge and negotiate learning goals throughout their interaction. In doing so, feedback becomes an explicit component of the preceptor-learner relationship. This enhances feedback interactions even in relatively brief encounters, and may begin an early educational alliance that can be elaborated with longer interactions.

  19. Installation of the ITER committee industry. Participants guide; Installation du Comite industrie ITER. Dossier des participants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    ITER is an international project to design and build an experimental fusion reactor based on the tokamak concept. This guide presents the ITER project and objectives and the associated organizations in France, the recommendations and actions for ITER, the industrial mobilization, the industrial committee and its members, technological sheets for the enterprises and the statistical document of the SESSI. (A.L.B.)

  20. Electrical tuning of mechanical characteristics in qPlus sensor: Active Q and resonance frequency control

    International Nuclear Information System (INIS)

    Lee, Manhee; Hwang, Jong Geun; Jahng, Junghoon; Kim, QHwan; Noh, Hanaul; An, Sangmin; Jhe, Wonho

    2016-01-01

    We present an electrical feedback method for independent and simultaneous tuning of both the resonance frequency and the quality factor of a harmonic oscillator, the so called “qPlus” configuration of quartz tuning forks. We incorporate a feedback circuit with two electronic gain parameters into the original actuation-detection system, and systematically demonstrate the control of the original resonance frequency of 32 592 Hz from 32 572 Hz to 32 610 Hz and the original quality factor 952 from 408 up to 20 000. This tunable module can be used for enhancing and optimizing the oscillator performance in compliance with specifics of applications.

  1. Iterative-Transform Phase Retrieval Using Adaptive Diversity

    Science.gov (United States)

    Dean, Bruce H.

    2007-01-01

    multiple intensity images are processed, each using a different defocus value. The processing is done by an iterative-transform method, yielding individual phase estimates corresponding to each image of the defocus-diversity data set. These individual phase estimates are combined in a weighted average to form a new phase estimate, which serves as the initial phase estimate for either the next iteration of the iterative-transform method or, if the maximum number of iterations has been reached, for the next several steps, which constitute the outerloop portion of the algorithm. The details of the next several steps must be omitted here for the sake of brevity. The overall effect of these steps is to adaptively update the diversity defocus values according to recovery of global defocus in the phase estimate. Aberration recovery varies with differing amounts as the amount of diversity defocus is updated in each image; thus, feedback is incorporated into the recovery process. This process is iterated until the global defocus error is driven to zero during the recovery process. The amplitude of aberration may far exceed one wavelength after completion of the inner-loop portion of the algorithm, and the classical iterative transform method does not, by itself, enable recovery of multi-wavelength aberrations. Hence, in the absence of a means of off-loading the multi-wavelength portion of the aberration, the algorithm would produce a wrapped phase map. However, a special aberration-fitting procedure can be applied to the wrapped phase data to transfer at least some portion of the multi-wavelength aberration to the diversity function, wherein the data are treated as known phase values. In this way, a multiwavelength aberration can be recovered incrementally by successively applying the aberration-fitting procedure to intermediate wrapped phase maps. During recovery, as more of the aberration is transferred to the diversity function following successive iterations around the ter loop

  2. Feedback Valence Affects Auditory Perceptual Learning Independently of Feedback Probability

    Science.gov (United States)

    Amitay, Sygal; Moore, David R.; Molloy, Katharine; Halliday, Lorna F.

    2015-01-01

    Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners’ responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability. PMID:25946173

  3. Iterative solvers in forming process simulations

    NARCIS (Netherlands)

    van den Boogaard, Antonius H.; Rietman, Bert; Huetink, Han

    1998-01-01

    The use of iterative solvers in implicit forming process simulations is studied. The time and memory requirements are compared with direct solvers and assessed in relation with the rest of the Newton-Raphson iteration process. It is shown that conjugate gradient{like solvers with a proper

  4. New concurrent iterative methods with monotonic convergence

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Qingchuan [Michigan State Univ., East Lansing, MI (United States)

    1996-12-31

    This paper proposes the new concurrent iterative methods without using any derivatives for finding all zeros of polynomials simultaneously. The new methods are of monotonic convergence for both simple and multiple real-zeros of polynomials and are quadratically convergent. The corresponding accelerated concurrent iterative methods are obtained too. The new methods are good candidates for the application in solving symmetric eigenproblems.

  5. The ITER Thomson scattering core LIDAR diagnostic

    NARCIS (Netherlands)

    Naylor, G.A.; Scannell, R.; Beurskens, M.; Walsh, M.J.; Pastor, I.; Donné, A.J.H.; Snijders, B.; Biel, W.; Meszaros, B.; Giudicotti, L.; Pasqualotto, R.; Marot, L.

    2012-01-01

    The central electron temperature and density of the ITER plasma may be determined by Thomson scattering. A LIDAR topology is proposed in order to minimize the port access required of the ITER vacuum vessel. By using a LIDAR technique, a profile of the electron temperature and density can be

  6. ITER ISS system alternative specification study

    International Nuclear Information System (INIS)

    Kveton, O.K.

    1990-08-01

    Recent comments suggested that the fuel systems, in particular the ISS, could be simplified if the ITER specifications were relaxed from the data specified for ITER. This interim report addresses the first part of the analysis, which considers the impact of design specifications on fuel systems design

  7. ITER jako živý

    Czech Academy of Sciences Publication Activity Database

    Řípa, Milan

    2010-01-01

    Roč. 10, č. 6 (2010), s. 18-19 Institutional research plan: CEZ:AV0Z20430508 Keywords : Fusion * ITER * magnetic field * ELMs * cryo pumps * central solenoid * correction coils * superconducting coils * toroidal field coils * poloidal field coils * divertor * Cadarache Subject RIV: BL - Plasma and Gas Discharge Physics http://www.tretipol.cz/900-iter-jako-zivy

  8. Iterative Brinkman penalization for remeshed vortex methods

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Koumoutsakos, Petros; Leonard, Anthony

    2015-01-01

    We introduce an iterative Brinkman penalization method for the enforcement of the no-slip boundary condition in remeshed vortex methods. In the proposed method, the Brinkman penalization is applied iteratively only in the neighborhood of the body. This allows for using significantly larger time...

  9. A note on some iterative roots

    Directory of Open Access Journals (Sweden)

    Paweł Solarz

    2009-04-01

    Full Text Available In this paper some orientation-preserving iterative roots of an orientation-preserving homeomorphism $Fcolon S^1o S^1$ which possess periodic points of order $n$ are considered. Namely, iterative roots with periodic points of order $n$. All orders of such roots are determined and their general construction is given.

  10. Controlled Iteration Grammars and Hyper-AFL's

    NARCIS (Netherlands)

    Asveld, P.R.J.

    1975-01-01

    We study $K$-iteration grammars equiped with a control on the application sequence of the substitutions, called $(\\Gamma,K)$-iteration grammars. In fact, the control is a language over the indices of the substitutions, prescribing the specific order in which one has to apply the different

  11. ITER Fast Ion Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Meo, Fernando; Korsholm, Søren Bang

    for measurements of the confined fusion alpha particles in ITER set by the ITER team. Then we outline the considerations, which enter into the selection and evaluation of CTS systems. System definition includes choice of probe frequency, geometry of probe and receiver beam patterns and probe power, but ultimately...

  12. Exponential Lower Bounds For Policy Iteration

    OpenAIRE

    Fearnley, John

    2010-01-01

    We study policy iteration for infinite-horizon Markov decision processes. It has recently been shown policy iteration style algorithms have exponential lower bounds in a two player game setting. We extend these lower bounds to Markov decision processes with the total reward and average-reward optimality criteria.

  13. TGV, hutě a tokamak ITER

    Czech Academy of Sciences Publication Activity Database

    Řípa, Milan

    Leden (2017) ISSN 2464-7888 Institutional support: RVO:61389021 Keywords : fusion * ITER * tokamak * TGV * Pulse Power Electrical Network * Steady State Electrical Network Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) http://www.3pol.cz/cz/rubriky/jaderna-fyzika-a-energetika/1954-tgv-hute-a-tokamak-iter

  14. Colorado Conference on iterative methods. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The conference provided a forum for many topics in iterative methods. Volume II presents sessions on these topics: nonsymmetric solvers, parallel computation, ODE solvers, multigrid and multilevel methods, applications, robust iterative methods, preconditioners, Toeplitz and circulant matrix solvers, and saddle point problems. Individual papers are indexed separately on the EDB.

  15. Iterative methods for weighted least-squares

    Energy Technology Data Exchange (ETDEWEB)

    Bobrovnikova, E.Y.; Vavasis, S.A. [Cornell Univ., Ithaca, NY (United States)

    1996-12-31

    A weighted least-squares problem with a very ill-conditioned weight matrix arises in many applications. Because of round-off errors, the standard conjugate gradient method for solving this system does not give the correct answer even after n iterations. In this paper we propose an iterative algorithm based on a new type of reorthogonalization that converges to the solution.

  16. ITER EDA newsletter. V. 7, no. 5

    International Nuclear Information System (INIS)

    1998-05-01

    This newsletter contains the articles 'The materials selection in ITER and the first materials workshop', 'US fusion community discussion on fusion strategies', 'ITER central solenoid model coil heat treatment complete and assembly started' and 'Programme of the 17th IAEA fusion energy conference'. There is also a note in memoriam of Hiroschi Shibata, who died on the 5th of June 1998

  17. NAIP 2015 Imagery Feedback

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — The NAIP 2015 Imagery Feedback web application allows users to make comments and observations about the quality of the 2015 National Agriculture Imagery Program...

  18. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  19. Feedback control for clinicians.

    Science.gov (United States)

    Dumont, Guy A

    2014-02-01

    Although feedback control and automation has revolutionized many fields of human activity, it has yet to have a significant impact on healthcare, particularly when a patient is in the loop. Although there have been a number of studies concerned with closed-loop control of anesthesia, they have yet to have an impact on clinical practice. For such systems to be successful, engineers and clinicians have to work hand in hand, for this they have to have a basic understanding of each other's fields. The goal of this paper is to introduce clinicians to basic concepts in control engineering, with an emphasis on the properties of feedback control. Concepts such as modelling for control, feedback and uncertainty, robustness, feedback controller such as proportional-integral-derivative control, predictive control and adaptive control are briefly reviewed. Finally we discuss the safety issues around closed-loop control and discuss ways by which safe control can be guaranteed.

  20. Mechanically stable tuning fork sensor with high quality factor for the atomic force microscope.

    Science.gov (United States)

    Kim, Kwangyoon; Park, Jun-Young; Kim, K B; Lee, Naesung; Seo, Yongho

    2014-01-01

    A quartz tuning fork was used instead of cantilever as a force sensor for the atomic force microscope. A tungsten tip was made by electrochemical etching from a wire of 50 µm diameter. In order to have mechanical stability of the tuning fork, it was attached on an alumina plate. The tungsten tip was attached on the inside end of a prong of a tuning fork. The phase shift was used as a feedback signal to control the distance between the tip and sample, and the amplitude was kept constant using a lock-in amplifier and a homemade automatic gain controller. Due to the mechanical stability, the sensor shows a high quality factor (∼10(3)), and the image quality obtained with this sensor was equivalent to that of the cantilever-based AFM. © 2014 Wiley Periodicals, Inc.

  1. Iterative learning control for electrical stimulation and stroke rehabilitation

    CERN Document Server

    Freeman, Chris T; Burridge, Jane H; Hughes, Ann-Marie; Meadmore, Katie L

    2015-01-01

    Iterative learning control (ILC) has its origins in the control of processes that perform a task repetitively with a view to improving accuracy from trial to trial by using information from previous executions of the task. This brief shows how a classic application of this technique – trajectory following in robots – can be extended to neurological rehabilitation after stroke. Regaining upper limb movement is an important step in a return to independence after stroke, but the prognosis for such recovery has remained poor. Rehabilitation robotics provides the opportunity for repetitive task-oriented movement practice reflecting the importance of such intense practice demonstrated by conventional therapeutic research and motor learning theory. Until now this technique has not allowed feedback from one practice repetition to influence the next, also implicated as an important factor in therapy. The authors demonstrate how ILC can be used to adjust external functional electrical stimulation of patients’ mus...

  2. ITER EDA newsletter. V. 4, no. 11

    International Nuclear Information System (INIS)

    1995-11-01

    This issue of the ITER EDA (Engineering Design Activities) Newsletter contains a report on the Ninth Meeting of the ITER Management Advisory Committee held in St. Petersburg, Russia, on November 3, 1995; a report on the Seventh International Conference on Fusion Reactor Materials held at Obninsk, Russia, 25-29 September, 1995; on the presentation of the ITER Project during a symposium on fusion energy held at Champaign, Illinois, USA, October 1-5, 1995; and on two meetings on ITER diagnostics, i.e., an international workshop on diagnostics for ITER held in Varenna, Italy, 28 August - 1 September, 1995; followed by the Third Diagnostics Expert Group Workshop held September 4-5 in the same location

  3. ITER EDA newsletter. V. 7, no. 9

    International Nuclear Information System (INIS)

    1998-09-01

    Newsletter containing the two articles 'Parties working on continuation of ITER EDA' and 'ITER exhibit at the Austria Centre, Vienna'. The first article describes efforts of the 4 ITER partners, the European Atomic Energy Community and the governments of Japan, the Russian Federation and the USA, to agree to continuation of the ITER EDA. While the former 3 partners signed an Extension to the EDA, the Americans were refused funding by the US Congress und will therefore be phased out within one year. Copies of the documents signed are provided. The second article reports on exhibition featuring a model of ITER and various other means of information on nuclear fusion which took place at the IAEA Headquarters from the 21st to 25th of September 1998. There is also an article in memoriam of Alexander V. Kashirski, who died on the 29th of September 1998

  4. Progress on Gyrotrons for ITER and Future Fusion Reactors

    Science.gov (United States)

    Thumm, Manfred K.

    2009-11-01

    The prototype of the Japan 170 GHz ITER gyrotron holds the energy and efficiency world record of 2.88 GJ (0.8 MW, 3600 s, 57%) with 55% efficiency at 1 MW, 800 s, whereas the Russian 170 GHz ITER prototype tube achieved 0.83 MW with a pulse duration of 203 s at 48% efficiency and 1 MW at 116 s and 52%. The record parameters of the European megawatt-class 140 GHz gyrotron for the Stellarator Wendelstein W7-X are: 0.92 MW output power at 1800 s pulse duration, almost 45% efficiency and 97.5% Gaussian mode purity. All these gyrotrons employ a cylindrical cavity, a quasi-optical output coupler, a synthetic diamond window and a single-stage depressed collector (SDC) for energy recovery. In coaxial cavities the existence of the longitudinally corrugated inner conductor reduces the problems of mode competition and limiting current, thus allowing one to use even higher order modes with lower Ohmic attenuation than in cylindrical cavities. Synthetic diamond windows with a transmission capability of 2 MW, continuous wave (CW) are feasible. In order to keep the number of the required gyrotrons and magnets as low as possible, to reduce the costs of the ITER 26 MW, 170 GHz ECRH system and to allow compact upper launchers for plasma stabilization, 2 MW mm-wave power per gyrotron tube is desirable. The FZK pre-prototype tube for an EU 170 GHz, 2 MW ITER gyrotron has achieved 1.8 MW at 28% efficiency (without depressed collector). Design studies for a 4 MW 170 GHz coaxial-cavity gyrotron with two synthetic diamond output windows and two 2 MW mm-wave output beams for future fusion reactors are currently being performed at FZK. The availability of sources with fast frequency tunability (several GHz s-1, tuning in 1.5-2.5% steps for about ten different frequencies) would permit the use of a simple, fixed, non-steerable mirror antenna for local current drive (ECCD) experiments and plasma stabilization. GYCOM in Russia develops in collaboration with IPP Garching and FZK an industrial

  5. RAMI analysis of the ITER CIS

    International Nuclear Information System (INIS)

    Kitazawa, Sin-iti; Okayama, Katsumi; Neyatani, Yuzuru; Sagot, Francois; Houtte, Didier van

    2014-01-01

    Highlights: • We performed the functional analysis of the ITER CIS. • We performed a failure mode analysis of the ITER CIS. • We estimated the reliability and availability of the ITER CIS. • The ITER RAMI approach was applied to the ITER CIS for technical risk control in the design phase. - Abstract: ITER is the first worldwide international project aiming to design a device that proves the physics and technological basis for fusion power plants to produce nuclear fusion energy. In the project, the RAMI approach (reliability, availability, maintainability and inspectability) has been adopted for technical risk control to guide the design of components in preparation for operation and maintenance. RAMI analysis of the ITER central interlock system (CIS), which shall provide investment protection for the ITER systems was performed on the conceptual design. A functional breakdown was prepared in a bottom-up approach, resulting in the system being divided into 5 main functions and 7 sub-functions which are described using the IDEFØ method. Reliability block diagrams (RBDs) were prepared to estimate the reliability and availability of each function under stipulated operating conditions. Initial and expected scenarios were analyzed to define risk-mitigation actions. The inherent availability of the ITER CIS expected after implementation of mitigating actions was calculated to be 99.86% over 2 years, which is the typical interval of the scheduled maintenance cycles. A failure modes, effects and criticality analysis (FMECA) was performed to initiate risk mitigation action. Criticality matrices highlight the risks of the different failure modes with regard to the probability of their occurrence and impact on operations. It was assessed that the availability of the ITER CIS, with appropriate mitigating actions applied, meets the project availability requirement for the system

  6. RAMI analysis of the ITER CIS

    Energy Technology Data Exchange (ETDEWEB)

    Kitazawa, Sin-iti, E-mail: kitazawa.siniti@jaea.go.jp [ITER Project unit, Japan Atomic Energy Agency (JAEA), Naka, Ibaraki (Japan); Okayama, Katsumi [ITER Organization, Route de Vinon sur Verdon, Saint Paul Lez Durance 13115 (France); Neyatani, Yuzuru [ITER Project unit, Japan Atomic Energy Agency (JAEA), Naka, Ibaraki (Japan); Sagot, Francois; Houtte, Didier van [ITER Organization, Route de Vinon sur Verdon, Saint Paul Lez Durance 13115 (France)

    2014-02-15

    Highlights: • We performed the functional analysis of the ITER CIS. • We performed a failure mode analysis of the ITER CIS. • We estimated the reliability and availability of the ITER CIS. • The ITER RAMI approach was applied to the ITER CIS for technical risk control in the design phase. - Abstract: ITER is the first worldwide international project aiming to design a device that proves the physics and technological basis for fusion power plants to produce nuclear fusion energy. In the project, the RAMI approach (reliability, availability, maintainability and inspectability) has been adopted for technical risk control to guide the design of components in preparation for operation and maintenance. RAMI analysis of the ITER central interlock system (CIS), which shall provide investment protection for the ITER systems was performed on the conceptual design. A functional breakdown was prepared in a bottom-up approach, resulting in the system being divided into 5 main functions and 7 sub-functions which are described using the IDEFØ method. Reliability block diagrams (RBDs) were prepared to estimate the reliability and availability of each function under stipulated operating conditions. Initial and expected scenarios were analyzed to define risk-mitigation actions. The inherent availability of the ITER CIS expected after implementation of mitigating actions was calculated to be 99.86% over 2 years, which is the typical interval of the scheduled maintenance cycles. A failure modes, effects and criticality analysis (FMECA) was performed to initiate risk mitigation action. Criticality matrices highlight the risks of the different failure modes with regard to the probability of their occurrence and impact on operations. It was assessed that the availability of the ITER CIS, with appropriate mitigating actions applied, meets the project availability requirement for the system.

  7. ITER Fast Plant System Controller prototype based on PXIe platform

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, M., E-mail: mariano.ruiz@upm.es [Grupo de Investigacion en Instrumentacion y Acustica Aplicada, CAEND CSIC-UPM Universidad Politecnica de Madrid, Crta. Valencia Km-7, Madrid 28031 (Spain); Vega, J.; Castro, R. [Asociacion EURATOM/CIEMAT para Fusion, Madrid (Spain); Sanz, D.; Lopez, J.M.; Arcas, G. de; Barrera, E.; Nieto, J. [Grupo de Investigacion en Instrumentacion y Acustica Aplicada, CAEND CSIC-UPM Universidad Politecnica de Madrid, Crta. Valencia Km-7, Madrid 28031 (Spain); Goncalves, B.; Sousa, J.; Carvalho, B. [Associacao EURATOM/IST, Lisbon (Portugal); Utzel, N.; Makijarvi, P. [ITER Organization, CS 90 046, 13067 St. Paul lez Durance Cedex (France)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Implementation of Fast Plant System Controller (FPSC) for ITER CODAC. Black-Right-Pointing-Pointer Efficient data acquisition and data movement using EPICS. Black-Right-Pointing-Pointer Performance of PCIe technologies in the implementation of FPSC. - Abstract: The ITER Fast Plant System Controller (FPSC) is based on embedded technologies. The FPSC will be devoted to both data acquisition tasks (sampling rates higher than 1 kHz) and control purposes (feedback loop actuators). Some of the essential requirements of these systems are: (a) data acquisition and data preprocessing; (b) interfacing with different networks and high speed links (Plant Operation Network, timing network based on IEEE1588, synchronous data transference and streaming/archiving networks); and (c) system setup and operation using EPICS (Experimental Physics and Industrial Control System) process variables. CIEMAT and UPM have implemented a prototype of FPSC using a PXIe (PCI eXtension for Instrumentation) form factor in a R and D project developed in two phases. The paper presents the main features of the two prototypes developed that have been named alpha and beta. The former was implemented using LabVIEW development tools as it was focused on modeling the FPSC software modules, using the graphical features of LabVIEW applications, and measuring the basic performance in the system. The alpha version prototype implements data acquisition with time-stamping, EPICS monitoring using waveform process variables (PVs), and archiving. The beta version prototype is a complete IOC implemented using EPICS with different software functional blocks. These functional blocks are integrated and managed using an ASYN driver solution and provide the basic functionalities required by ITER FPSC such as data acquisition, data archiving, data pre-processing (using both CPU and GPU) and streaming.

  8. Development of the low-field side reflectometer for ITER

    Science.gov (United States)

    Muscatello, Christopher; Anderson, James; Gattuso, Anthony; Doyle, Edward; Peebles, William; Seraydarian, Raymond; Wang, Guiding; Kramer, Gerrit; Zolfaghari, Ali; Atomics Team, General; University of California Los Angeles Team; Princeton Plasma Physics Laboratory Team

    2017-10-01

    The Low-Field Side Reflectometer (LFSR) for ITER will provide real-time edge density profiles every 10 ms for feedback control and every 24 μs for physics evaluation. The spatial resolution will be better than 5 mm over 30 - 165 GHz, probing the scrape-off layer to the top of the pedestal in H-mode plasmas. An antenna configuration has been selected for measurements covering anticipated plasma elevations. Laboratory validation of diagnostic performance is underway using a LFSR transmission line (TL) mockup. The 40-meter TL includes circular corrugated waveguide, length calibration feature, Gaussian telescope, vacuum windows, containment membranes, and expansion joint. Transceiver modules coupled to the input of the TL provide frequency-modulated (FM) data for evaluation of performance as a monostatic reflectometer. Results from the mockup tests are presented and show that, with some further optimization, the LFSR will meet or exceed the measurement requirements for ITER. An update of the LFSR instrumentation design status is also presented with preliminary test results. Work supported by PPPL under subcontract S013252-A.

  9. ITER CTA newsletter. No. 14, November 2002

    International Nuclear Information System (INIS)

    2003-01-01

    The Sixth ITER Negotiations Meeting (N6) took place on 29-30 October 2002 at Rokkasho-mura in the Aomori Prefecture - the location of the site that Japan has offered to host the ITER project. Japan hosted the meeting, which was also attended by delegations from Canada, the European Union, and the Russian Federation. At the start of the meeting, Mr. Yoshiro Mori, the former Prime Minister of Japan said that energy issues are important to achieving human prosperity, world peace and conservation of the environment, and that therefore the Japanese Government as a whole should promote the ITER project under international collaboration to realize fusion energy. The JA delegation reported that JA had sent a letter to China on 22 October 2002 on behalf of the ITER Negotiators in response to a letter from Mr. Liu, Vice Minister of Science and Technology of China. The Canadian delegation reported on the special informal ITER session at the IAEA Fusion Energy Conference in Lyon, France, and noted that it raised the ITER profile in a positive way. The EU delegation reported on the adoption, within the Sixth Framework Programme, of the Specific Euratom Programme, which gives an explicit basis for continuing activities in the period up to the end of 2006, including a provision of up to Euro 200 million for a possible start of ITER construction. The RF delegation reported that the ITER activities in the Russian Federation are conducted in accordance with the Federal Program (2002-2005) approved by the Russian Government. Funding for ITER activities in 2003 is expected to be on the same level as in previous years. It was reported that the mandate of the Russian delegation to participate in the Negotiations in 2003 is expected to be approved soon by the Government. The RF delegation also reported that they had received informal enquiries from the Republic of Korea about possible participation in ITER. Significant progress was also made on a wide range of other issues, including

  10. Adaptive iterative learning control for a class of non-linearly parameterised systems with input saturations

    Science.gov (United States)

    Zhang, Ruikun; Hou, Zhongsheng; Ji, Honghai; Yin, Chenkun

    2016-04-01

    In this paper, an adaptive iterative learning control scheme is proposed for a class of non-linearly parameterised systems with unknown time-varying parameters and input saturations. By incorporating a saturation function, a new iterative learning control mechanism is presented which includes a feedback term and a parameter updating term. Through the use of parameter separation technique, the non-linear parameters are separated from the non-linear function and then a saturated difference updating law is designed in iteration domain by combining the unknown parametric term of the local Lipschitz continuous function and the unknown time-varying gain into an unknown time-varying function. The analysis of convergence is based on a time-weighted Lyapunov-Krasovskii-like composite energy function which consists of time-weighted input, state and parameter estimation information. The proposed learning control mechanism warrants a L2[0, T] convergence of the tracking error sequence along the iteration axis. Simulation results are provided to illustrate the effectiveness of the adaptive iterative learning control scheme.

  11. Bayesian networks: a combined tuning heuristic

    NARCIS (Netherlands)

    Bolt, J.H.

    2016-01-01

    One of the issues in tuning an output probability of a Bayesian network by changing multiple parameters is the relative amount of the individual parameter changes. In an existing heuristic parameters are tied such that their changes induce locally a maximal change of the tuned probability. This

  12. Tuning and History: A Personal Overview

    Science.gov (United States)

    Isaacs, Ann Katherine

    2017-01-01

    The text places Tuning History in the context of the rapidly developing international collaboration among historians which began in Europe in 1989, with the ECTS Pilot project, and continued, from 2000 on, with the European History Networks (for research and for curriculum development) working in parallel and in collaboration with Tuning, in…

  13. Efficient tuning in supervised machine learning

    NARCIS (Netherlands)

    Koch, Patrick

    2013-01-01

    The tuning of learning algorithm parameters has become more and more important during the last years. With the fast growth of computational power and available memory databases have grown dramatically. This is very challenging for the tuning of parameters arising in machine learning, since the

  14. Active beam spectroscopy for ITER

    International Nuclear Information System (INIS)

    Von Hellermann, M.; Giroud, C.; Jaspers, R.; Hawkes, N.C.; Mullane, M.O.; Zastrow, K.D.; Krasilnikov, A.; Tugarinov, S.; Lotte, P.; Malaquias, A.; Rachlew, E.

    2003-01-01

    The latest status of 'Active Beam' related spectroscopy aspects as part of the ITER diagnostic scenario is presented. A key issue of the proposed scheme is based on the concept that in order to achieve the ultimate goal of global data consistency, all particles involved, that is, intrinsic and seeded impurity ions as well as helium ash ions and bulk plasma ions and also the plasma background data (e.g. magnetic and electric fields, electron density and temperature profiles) need to be addressed. A further sensible step in this direction is the decision of exploiting both a dedicated low-energy, low-power diagnostic beam (DNB, 2.2 MW 100 keV/amu) as well as the high-power, high-energy heating beams (HNB, 17 MW 500 keV/amu) for maximum diagnostic information. The authors report some new aspects referring to the use of DNB for motional Stark effect (MSE) where the main idea is to treat both beams (HNB and DNB) as potential diagnostic tools with complementary roles. The equatorial ports for the DNB promise excellent spatial resolution, however, the angles are less favourable for a polarimetric MSE exploitation. HNB can be used as probe beam for diagnosing slowing-down fusion alpha with a birth energy of 3,5 MeV

  15. Advanced fuelling system for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Raman, Roger [University of Washington, Seattle, WA (United States)], E-mail: raman@aa.washington.edu

    2008-12-15

    Steady-state high-performance discharges in reactors, such as the Advanced Tokamak (AT) scenarios would rely on optimized density and pressure profiles that must be maintained. This maximizes the bootstrap current fraction, reduces reactor recycling power and reduces thermal stresses. Other than a system for the balance of current drive not provided by bootstrap current drive, no other sources of input power, such as from neutral beams, are allowed. For these systems, a precision fuelling system would be the ideal way to control the fusion burn by controlling and maintaining the required pressure profile. This requires a fuelling system that is capable of depositing fuel at any radial location within the plasma while at the same time not altering the density profile to a level that degrades the required pressure profile. Present fuelling systems are incapable of meeting these requirements. An advanced fuelling system based on Compact Toroid injection has the potential to meet these needs while simultaneously providing a source of toroidal momentum input. Description of a conceptual Compact Toroid fueller for ITER is presented in conjunction with a plan for developing this much needed technology.

  16. Magnetic fusion and project ITER

    International Nuclear Information System (INIS)

    Park, H.K.

    1992-01-01

    It has already been demonstrated that our economics and international relationship are impacted by an energy crisis. For the continuing prosperity of the human race, a new and viable energy source must be developed within the next century. It is evident that the cost will be high and will require a long term commitment to achieve this goal due to a high degree of technological and scientific knowledge. Energy from the controlled nuclear fusion is a safe, competitive, and environmentally attractive but has not yet been completely conquered. Magnetic fusion is one of the most difficult technological challenges. In modem magnetic fusion devices, temperatures that are significantly higher than the temperatures of the sun have been achieved routinely and the successful generation of tens of million watts as a result of scientific break-even is expected from the deuterium and tritium experiment within the next few years. For the practical future fusion reactor, we need to develop reactor relevant materials and technologies. The international project called ''International Thermonuclear Experimental Reactor (ITER)'' will fulfill this need and the success of this project will provide the most attractive long-term energy source for mankind

  17. Iterants, Fermions and Majorana Operators

    Science.gov (United States)

    Kauffman, Louis H.

    Beginning with an elementary, oscillatory discrete dynamical system associated with the square root of minus one, we study both the foundations of mathematics and physics. Position and momentum do not commute in our discrete physics. Their commutator is related to the diffusion constant for a Brownian process and to the Heisenberg commutator in quantum mechanics. We take John Wheeler's idea of It from Bit as an essential clue and we rework the structure of that bit to a logical particle that is its own anti-particle, a logical Marjorana particle. This is our key example of the amphibian nature of mathematics and the external world. We show how the dynamical system for the square root of minus one is essentially the dynamics of a distinction whose self-reference leads to both the fusion algebra and the operator algebra for the Majorana Fermion. In the course of this, we develop an iterant algebra that supports all of matrix algebra and we end the essay with a discussion of the Dirac equation based on these principles.

  18. Automatic tuning of free electron lasers

    International Nuclear Information System (INIS)

    Agapov, Ilya; Zagorodnov, Igor; Geloni, Gianluca; Tomin, Sergey

    2017-01-01

    Existing FEL facilities often suffer from stability issues: so electron orbit, transverse electron optics, electron bunch compression and other parameters have to be readjusted often to account for drifts in performance of various components. The tuning procedures typically employed in operation are often manual and lengthy. We have been developing a combination of model-free and model-based automatic tuning methods to meet the needs of present and upcoming XFEL facilities. Our approach has been implemented at FLASH to achieve automatic SASE tuning using empirical control of orbit, electron optics and bunch compression. In this paper we describe our approach to empirical tuning, the software which implements it, and the results of using it at FLASH.We also discuss the potential of using machine learning and model-based techniques in tuning methods.

  19. Block-Iterative Frequency-Domain Equalizations for SC-IDMA Systems

    Directory of Open Access Journals (Sweden)

    Salah Awad Salman

    2015-07-01

    Full Text Available In wireless broadband communications using single-carrier interleave division multiple access (SC-IDMA systems, efficient multiuser detection (MUD classes that make use of joint hybrid decision feedback equalization (HDFE/ frequency decision-feedback equalization (FDFE and interference cancellation (IC techniques, are proposed in conjunction with channel coding to deal with several users accessing the multipath fading channels. In FDFE-IDMA, the feedforward (FF and feedback (FB filtering operations of FDFE, which use to remove intersymbol interference (ISI, are implemented by Fast Fourier Transforms (FFTs, while in HDFE-IDMA the only FF filter is implemented by FFTs. Further, the parameters involved in the FDFE/HDFE filtering are derived according to the minimum mean square error (MMSE criteria, and the feedback symbol decisions are directly designed from soft detection of the decoded signals at the previous iteration. The simulation results including comparisons with those of frequency domain equalization (FDE, SC-FDE-IDMA and multi-carrier OFDM-IDMA schemes, with cyclic prefixing (CP and zero padding (ZP techniques, show that the combination of FDFE-IC/HDFE-IC provides an efficient solution with good performance for IDMA systems in ISI channels. Moreover, these iterative structures with block equalization yield a much lower complexity than equivalent existing structures, making them attractive for a wealth of applications.

  20. People's Republic of China joins ITER

    International Nuclear Information System (INIS)

    Huo Yuping

    2003-01-01

    The People's Republic of China is the largest developing country with a projected population of 1.6 - 2 billion people and an energy consumption growing from the current 1.3 Billion Tons Coal Equivalent (TCE) to more than 4 Billion TCE by 2050. This large demand needs to be accommodated in a sustainable way, requiring energy generation in an environmentally friendly way. Fusion is one of the most promising candidates to solve this important issue. This explains why in the second half of 2002, the ITER Participants' delegations to the ITER Negotiations received expression of interest from the People's Republic of China in the possibility of Chinese participation in ITER, including joining the ongoing Negotiations. The speed with which the Chinese authorities had made their decision to participate in the ITER Negotiations was impressive. The Prime Minister and the State Council had already confirmed their decision to apply to join ITER as soon as possible, and Mr. Xu Guanhua, Chinese Minister of Science and Technology, wrote on behalf of his government, on 10 January 2003, to the four heads of delegation in the ITER Negotiations, requesting that China participate in the present ITER Negotiations, pointing out that China intends to provide a substantial contribution to the Project, comparable to what is currently envisaged by some of the participants in the present Negotiations

  1. Iterative solutions of finite difference diffusion equations

    International Nuclear Information System (INIS)

    Menon, S.V.G.; Khandekar, D.C.; Trasi, M.S.

    1981-01-01

    The heterogeneous arrangement of materials and the three-dimensional character of the reactor physics problems encountered in the design and operation of nuclear reactors makes it necessary to use numerical methods for solution of the neutron diffusion equations which are based on the linear Boltzmann equation. The commonly used numerical method for this purpose is the finite difference method. It converts the diffusion equations to a system of algebraic equations. In practice, the size of this resulting algebraic system is so large that the iterative methods have to be used. Most frequently used iterative methods are discussed. They include : (1) basic iterative methods for one-group problems, (2) iterative methods for eigenvalue problems, and (3) iterative methods which use variable acceleration parameters. Application of Chebyshev theorem to iterative methods is discussed. The extension of the above iterative methods to multigroup neutron diffusion equations is also considered. These methods are applicable to elliptic boundary value problems in reactor design studies in particular, and to elliptic partial differential equations in general. Solution of sample problems is included to illustrate their applications. The subject matter is presented in as simple a manner as possible. However, a working knowledge of matrix theory is presupposed. (M.G.B.)

  2. Regularized iterative weighted filtered backprojection for helical cone-beam CT

    International Nuclear Information System (INIS)

    Sunnegaardh, Johan; Danielsson, Per-Erik

    2008-01-01

    Contemporary reconstruction methods employed for clinical helical cone-beam computed tomography (CT) are analytical (noniterative) but mathematically nonexact, i.e., the reconstructed image contains so called cone-beam artifacts, especially for higher cone angles. Besides cone artifacts, these methods also suffer from windmill artifacts: alternating dark and bright regions creating spiral-like patterns occurring in the vicinity of high z-direction derivatives. In this article, the authors examine the possibility to suppress cone and windmill artifacts by means of iterative application of nonexact three-dimensional filtered backprojection, where the analytical part of the reconstruction brings about accelerated convergence. Specifically, they base their investigations on the weighted filtered backprojection method [Stierstorfer et al., Phys. Med. Biol. 49, 2209-2218 (2004)]. Enhancement of high frequencies and amplification of noise is a common but unwanted side effect in many acceleration attempts. They have employed linear regularization to avoid these effects and to improve the convergence properties of the iterative scheme. Artifacts and noise, as well as spatial resolution in terms of modulation transfer functions and slice sensitivity profiles have been measured. The results show that for cone angles up to ±2.78 deg., cone artifacts are suppressed and windmill artifacts are alleviated within three iterations. Furthermore, regularization parameters controlling spatial resolution can be tuned so that image quality in terms of spatial resolution and noise is preserved. Simulations with higher number of iterations and long objects (exceeding the measured region) verify that the size of the reconstructible region is not reduced, and that the regularization greatly improves the convergence properties of the iterative scheme. Taking these results into account, and the possibilities to extend the proposed method with more accurate modeling of the acquisition process

  3. An Iterative Learning Control Technique for Point-to-Point Maneuvers Applied on an Overhead Crane

    Directory of Open Access Journals (Sweden)

    Khaled A. Alhazza

    2014-01-01

    Full Text Available An iterative learning control (ILC strategy is proposed, and implemented on simple pendulum and double pendulum models of an overhead crane undergoing simultaneous traveling and hoisting maneuvers. The approach is based on generating shaped commands using the full nonlinear equations of motion combined with the iterative learning control, to use as acceleration commands to the jib of the crane. These acceleration commands are tuned to eliminate residual oscillations in rest-to-rest maneuvers. The performance of the proposed strategy is tested using an experimental scaled model of an overhead crane with hoisting. The shaped command is derived analytically and validated experimentally. Results obtained showed that the proposed ILC control strategy is capable of eliminating travel and residual oscillations in simple and double pendulum models with hoisting. It is also shown, in all cases, that the proposed approach has a low sensitivity to the initial cable lengths.

  4. ITER Council proceedings: April 1988 - August 1989

    International Nuclear Information System (INIS)

    1990-01-01

    The ITER documentation series, of which this is the sixth report, began with a concise record of the decisions and actions taken in establishing ITER. The contents of that first report include the Terms of Reference Concerning Conceptual Design Activities for an International Thermonuclear Experimental Reactor. The Terms of Reference, which were part of the IAEA's invitation to the prospective parties, formally describe how the co-operative work of the four Parties in the specified activities is directed and managed. The first report in the series also covered activities from the initial meeting of the ITER Quadripartite Initiative Committee in March 1987 through March 1988. The present report is intended to make available in convenient form the essential information on ''landmark'' events in the direction of the ITER activities from the first meeting of the ITER Council (IC), in April 1988, through the letter report by the Council following their fourth meeting in July 1989. This report therefore covers approximately the first half of the Conceptual Design Activities, which are to be concluded in December 1990. THe next section of this report provides, for convenient reference, an overview of the organization and schedule that were adopted for the ITER activities through 1990. The sections that follow contain, for each of the four IC meetings during the period covered by this report, a copy of the official record of the transactions. The written reports of the ITER Management Committee (IMC) and the ITER Scientific and Technical Advisory Committee (ISTAC) to the IC in connection with the meetings are represented by summaries, prepared by the ITER Secretariat. These summaries include direct quotations of especially significant statements in the reports. In general, other supporting material is included only if it is of more than transitory significance. 1 fig and tabs

  5. Potential for Australian involvement in ITER

    International Nuclear Information System (INIS)

    O'Connor, D. J.; Collins, G. A.; Hole, M. J.

    2006-01-01

    Full text: Full text: Fusion, the process that powers the sun and stars, offers a solution to the world's long-term energy needs: providing large scale energy production with zero greenhouse gas emissions, short-lived radio-active waste compared to conventional nuclear fission cycles, and a virtually limitless supply of fuel. Almost three decades of fusion research has produced spectacular progress. Present-day experiments have a power gain ratio of approximately 1 (ratio of power out to power in), with a power output in the 10's of megawatts. The world's next major fusion experiment, the International Thermonuclear Experimental Reactor (ITER), will be a pre-prototype power plant. Since announcement of the ITER site in June 2005, the ITER project, has gained momentum and political support. Despite Australia's foundation role in the field of fusion science, through the pioneering work of Sir Mark Oliphant, and significant contributions to the international fusion program over the succeeding years, Australia is not involved in the ITER project. In this talk, the activities of a recently formed consortium of scientists and engineers, the Australian ITER Forum will be outlined. The Forum is drawn from five Universities, ANSTO (the Australian Nuclear Science and Technology Organisation) and AINSE (the Australian Institute for Nuclear Science and Engineering), and seeks to promote fusion energy in the Australian community and negotiate a role for Australia in the ITER project. As part of this activity, the Australian government recently funded a workshop that discussed the ways and means of engaging Australia in ITER. The workshop brought the research, industrial, government and general public communities, together with the ITER partners, and forged an opportunity for ITER engagement; with scientific, industrial, and energy security rewards for Australia. We will report on the emerging scope for Australian involvement

  6. A modular positive feedback-based gene amplifier

    Directory of Open Access Journals (Sweden)

    Bhalerao Kaustubh D

    2010-02-01

    Full Text Available Abstract Background Positive feedback is a common mechanism used in the regulation of many gene circuits as it can amplify the response to inducers and also generate binary outputs and hysteresis. In the context of electrical circuit design, positive feedback is often considered in the design of amplifiers. Similar approaches, therefore, may be used for the design of amplifiers in synthetic gene circuits with applications, for example, in cell-based sensors. Results We developed a modular positive feedback circuit that can function as a genetic signal amplifier, heightening the sensitivity to inducer signals as well as increasing maximum expression levels without the need for an external cofactor. The design utilizes a constitutively active, autoinducer-independent variant of the quorum-sensing regulator LuxR. We experimentally tested the ability of the positive feedback module to separately amplify the output of a one-component tetracycline sensor and a two-component aspartate sensor. In each case, the positive feedback module amplified the response to the respective inducers, both with regards to the dynamic range and sensitivity. Conclusions The advantage of our design is that the actual feedback mechanism depends only on a single gene and does not require any other modulation. Furthermore, this circuit can amplify any transcriptional signal, not just one encoded within the circuit or tuned by an external inducer. As our design is modular, it can potentially be used as a component in the design of more complex synthetic gene circuits.

  7. ITER technical term bilingual glossary year 2008 first half edition

    International Nuclear Information System (INIS)

    Sato, Koichi; Sengoku, Akio; Kitazawa, Sin-iti; Neyatani, Yuzuru; Koizumi, Koichi; Seki, Fumiko; Hasegawa, Shiori

    2008-09-01

    On October 24th, 2007, the Agreement on the Establishment of the ITER International Fusion Energy Organization for the Joint Implementation of the ITER Project (the 'ITER Agreement') came into force, and Japan Atomic Energy Agency (JAEA) was appointed to a Domestic Agency (DA). The DA will contribute to the ITER construction in cooperation with ITER Organization (IO) where many ITER-specific technical terms and abbreviations were used. This book is a collection of those terms and abbreviations translated to Japanese. (author)

  8. ITER EDA Newsletter. V. 4, no. 8

    International Nuclear Information System (INIS)

    1995-08-01

    This ITER EDA (Engineering Design Activities) Newsletter issue contains reports on the 8th meeting of the ITER council and on the first Special Review Group (SRG) meeting held 21-23 June, 1995, at the San Diego Joint Work Site, USA. The SWG was established in July 1994 to review the technical, social, and the safety and environmental requirements for siting ITER which will be prepared by the Director and the JCT, and to report the results of the review to the council. Furthermore, a description of the design office at the Garching Joint Work Site is given

  9. Iterated rippled noise discrimination at long durations

    OpenAIRE

    Yost, William A.

    2009-01-01

    Iterated rippled noise (IRN) was used to study discrimination of IRN stimuli with a lower number of iterations from IRN stimuli with a higher number of iterations as a function of stimulus duration (100–2000 ms). Such IRN stimuli differ in the strength of the repetition pitch. In some cases, the gain used to generate IRN stimuli was adjusted so that both IRN stimuli in the discrimination task had the same height of the first peak in the autocorrelation function or autocorrelogram. In previous...

  10. Studies for site preparation for ITER construction

    International Nuclear Information System (INIS)

    Fardeau, A.; Blanc, F.; Cardettini, J.D.; Mandine, J.R.; Guerin, R.; Patisson, L.; Bergegere, P.; Santagiustina, A.; Garin, P.

    2004-01-01

    The implantation of a nuclear facility such as ITER (about 20 buildings on 40 ha) requires many preparatory studies, particularly with respect to: Underground characteristics; Topography, layout; Deforestation, excavations; Networks, fences and roads; Impact of seismic hazard on design. This paper presents the main results of these studies, carried out within the European ITER Site Studies framework. A dedicated paper in the conference deals with the transport studies. To choose the site for ITER implantation, detailed geological, hydrogeological and geophysical investigations have been carried out. Taking into account the meteorological data (particularly the main wind direction), topography, access, electrical supply, fluids needs and constraints (gravity systems), buildings and roads have been implemented. (authors)

  11. Structural analysis of the ITER Vacuum Vessel regarding 2012 ITER Project-Level Loads

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.-M., E-mail: jean-marc.martinez@live.fr [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Jun, C.H.; Portafaix, C.; Choi, C.-H.; Ioki, K.; Sannazzaro, G.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); Cambazar, M.; Corti, Ph.; Pinori, K.; Sfarni, S.; Tailhardat, O. [Assystem EOS, 117 rue Jacquard, L' Atrium, 84120 Pertuis (France); Borrelly, S. [Sogeti High Tech, RE2, 180 rue René Descartes, Le Millenium – Bat C, 13857 Aix en Provence (France); Albin, V.; Pelletier, N. [SOM Calcul – Groupe ORTEC, 121 ancien Chemin de Cassis – Immeuble Grand Pré, 13009 Marseille (France)

    2014-10-15

    Highlights: • ITER Vacuum Vessel is a part of the first barrier to confine the plasma. • ITER Vacuum Vessel as Nuclear Pressure Equipment (NPE) necessitates a third party organization authorized by the French nuclear regulator to assure design, fabrication, conformance testing and quality assurance, i.e. Agreed Notified Body (ANB). • A revision of the ITER Project-Level Load Specification was implemented in April 2012. • ITER Vacuum Vessel Loads (seismic, pressure, thermal and electromagnetic loads) were summarized. • ITER Vacuum Vessel Structural Margins with regards to RCC-MR code were summarized. - Abstract: A revision of the ITER Project-Level Load Specification (to be used for all systems of the ITER machine) was implemented in April 2012. This revision supports ITER's licensing by accommodating requests from the French regulator to maintain consistency with the plasma physics database and our present understanding of plasma transients and electro-magnetic (EM) loads, to investigate the possibility of removing unnecessary conservatism in the load requirements and to review the list and definition of incidental cases. The purpose of this paper is to present the impact of this 2012 revision of the ITER Project-Level Load Specification (LS) on the ITER Vacuum Vessel (VV) loads and the main structural margins required by the applicable French code, RCC-MR.

  12. Pinhole Luminosity Monitor with Feedback

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, J

    2004-05-17

    Previously, the generalized luminosity L was defined and calculated for all incident channels based on an NLC e{sup +}e{sup -} design. Alternatives were then considered to improve the differing beam-beam e{sup -}e{sup -} e{gamma} and {gamma}{gamma} channels. Regardless of the channel, there was a large flux of outgoing, high energy photons that were produced from the beam-beam interaction e.g. beamsstrahlung that needs to be disposed of and whose flux depended on L. One approach to this problem is to consider it a resource and attempt to take advantage of it by disposing of these straight-ahead photons in more useful ways than simply dumping them. While there are many options for monitoring the luminosity, any method that allows feedback and optimization in real time and in a non-intercepting and non-interfering way during normal data taking is extremely important--especially if it provides other capabilities such as high resolution tuning of spot sizes and can be used for all incident channels without essential modifications to their setup. Our ''pin-hole'' camera appears to be such a device if it can be made to work with high energy photons in ways that are compatible with the many other constraints and demands on space around the interaction region. The basis for using this method is that it has, in principle, the inherent resolution and bandwidth to monitor the very small spot sizes and their stabilities that are required for very high, integrated luminosity. While there are many possible, simultaneous uses of these outgoing photon beams, we limit our discussion to a single, blind, proof-of-principle experiment that was done on the FFTB line at SLAC to certify the concept of a camera obscura for high energy photons.

  13. The Impact of the Immediate Feedback Assessment Technique on Course Evaluations

    Science.gov (United States)

    Maurer, Trent W.; Kropp, Jerri J.

    2015-01-01

    This project reports the results of two studies that investigated the impact on course evaluations of using partial credit iterative responding (PCIR) with the Immediate Feedback Assessment Technique (IF-AT) forms on summative course assessments. This project also quantifies grade inflation from utilizing different PCIR schemes and documents the…

  14. Guidelines : the do's, don'ts and don't knows of feedback for clinical education

    NARCIS (Netherlands)

    Lefroy, Janet; Watling, Chris; Teunissen, Pim W; Brand, Paul

    2015-01-01

    INTRODUCTION: The guidelines offered in this paper aim to amalgamate the literature on formative feedback into practical Do's, Don'ts and Don't Knows for individual clinical supervisors and for the institutions that support clinical learning. METHODS: The authors built consensus by an iterative

  15. Feedback Conversations: Creating Feedback Dialogues with a New Textual Tool for Industrial Design Student Feedback

    Science.gov (United States)

    Funk, Mathias; van Diggelen, Migchiel

    2017-01-01

    In this paper, the authors describe how a study of a large database of written university teacher feedback in the department of Industrial Design led to the development of a new conceptual framework for feedback and the design of a new feedback tool. This paper focuses on the translation of related work in the area of feedback mechanisms for…

  16. Progress of ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Ioki, K., E-mail: Kimihiro.Ioki@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Bayon, A. [F4E, c/ Josep Pla, No. 2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Choi, C.H.; Daly, E.; Dani, S.; Davis, J.; Giraud, B.; Gribov, Y.; Hamlyn-Harris, C.; Jun, C.; Levesy, B. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Kim, B.C. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Kuzmin, E. [NTC “Sintez”, Efremov Inst., 189631 Metallostroy, St. Petersburg (Russian Federation); Le Barbier, R.; Martinez, J.-M. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Pathak, H. [ITER-India, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382025 (India); Preble, J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Sa, J.W. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Terasawa, A.; Utin, Yu. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); and others

    2013-10-15

    Highlights: ► This covers the overall status and progress of the ITER vacuum vessel activities. ► It includes design, R and D, manufacturing and approval process of the regulators. ► The baseline design was completed and now manufacturing designs are on-going. ► R and D includes ISI, dynamic test of keys and lip-seal welding/cutting technology. ► The VV suppliers produced full-scale mock-ups and started VV manufacturing. -- Abstract: Design modifications were implemented in the vacuum vessel (VV) baseline design in 2011–2012 for finalization. The modifications are mostly due to interface components, such as support rails and feedthroughs for the in-vessel coils (IVC). Manufacturing designs are being developed at the domestic agencies (DAs) based on the baseline design. The VV support design was also finalized and tests on scale mock-ups are under preparation. Design of the in-wall shielding (IWS) has progressed, considering the assembly methods and the required tolerances. Further modifications are required to be consistent with the DAs’ manufacturing designs. Dynamic tests on the inter-modular and stub keys to support the blanket modules are being performed to measure the dynamic amplification factor (DAF). An in-service inspection (ISI) plan has been developed and R and D was launched for ISI. Conceptual design of the VV instrumentation has been developed. The VV baseline design was approved by the agreed notified body (ANB) in accordance with the French Nuclear Pressure Equipment Order procedure.

  17. Progress of ITER vacuum vessel

    International Nuclear Information System (INIS)

    Ioki, K.; Bayon, A.; Choi, C.H.; Daly, E.; Dani, S.; Davis, J.; Giraud, B.; Gribov, Y.; Hamlyn-Harris, C.; Jun, C.; Levesy, B.; Kim, B.C.; Kuzmin, E.; Le Barbier, R.; Martinez, J.-M.; Pathak, H.; Preble, J.; Sa, J.W.; Terasawa, A.; Utin, Yu.

    2013-01-01

    Highlights: ► This covers the overall status and progress of the ITER vacuum vessel activities. ► It includes design, R and D, manufacturing and approval process of the regulators. ► The baseline design was completed and now manufacturing designs are on-going. ► R and D includes ISI, dynamic test of keys and lip-seal welding/cutting technology. ► The VV suppliers produced full-scale mock-ups and started VV manufacturing. -- Abstract: Design modifications were implemented in the vacuum vessel (VV) baseline design in 2011–2012 for finalization. The modifications are mostly due to interface components, such as support rails and feedthroughs for the in-vessel coils (IVC). Manufacturing designs are being developed at the domestic agencies (DAs) based on the baseline design. The VV support design was also finalized and tests on scale mock-ups are under preparation. Design of the in-wall shielding (IWS) has progressed, considering the assembly methods and the required tolerances. Further modifications are required to be consistent with the DAs’ manufacturing designs. Dynamic tests on the inter-modular and stub keys to support the blanket modules are being performed to measure the dynamic amplification factor (DAF). An in-service inspection (ISI) plan has been developed and R and D was launched for ISI. Conceptual design of the VV instrumentation has been developed. The VV baseline design was approved by the agreed notified body (ANB) in accordance with the French Nuclear Pressure Equipment Order procedure

  18. A feedback microprocessor for hadron colliders

    International Nuclear Information System (INIS)

    Herrup, D.A.; Chapman, L.; Franck, A.; Groves, T.; Lublinsky, B.

    1992-12-01

    A feedback microprocessor has been built for the TEVATRON. It has been constructed to be applicable to hadron colliders in general. Its inputs are realtime accelerator measurements, data describing the state of the TEVATRON, and ramp tables. The microprocessor software includes a finite state machine. Each state corresponds to a specific TEVATRON operation and has a state-specific TEVATRON model. Transitions between states are initiated by the global TEVATRON clock. Each state includes a cyclic routine which is called periodically and where all calculations are performed. The output corrections are inserted onto a fast TEVATRON-wide link from which the power supplies will read the realtime corrections. We also store all of the input data and output corrections in a set of buffers which can easily be retrieved for diagnostic analysis. In this paper we will describe this device and its use to control the TEVATRON tunes as well as other possible applications

  19. Climate forcings and feedbacks

    Science.gov (United States)

    Hansen, James

    1993-01-01

    Global temperature has increased significantly during the past century. Understanding the causes of observed global temperature change is impossible in the absence of adequate monitoring of changes in global climate forcings and radiative feedbacks. Climate forcings are changes imposed on the planet's energy balance, such as change of incoming sunlight or a human-induced change of surface properties due to deforestation. Radiative feedbacks are radiative changes induced by climate change, such as alteration of cloud properties or the extent of sea ice. Monitoring of global climate forcings and feedbacks, if sufficiently precise and long-term, can provide a very strong constraint on interpretation of observed temperature change. Such monitoring is essential to eliminate uncertainties about the relative importance of various climate change mechanisms including tropospheric sulfate aerosols from burning of coal and oil smoke from slash and burn agriculture, changes of solar irradiance changes of several greenhouse gases, and many other mechanisms. The considerable variability of observed temperature, together with evidence that a substantial portion of this variability is unforced indicates that observations of climate forcings and feedbacks must be continued for decades. Since the climate system responds to the time integral of the forcing, a further requirement is that the observations be carried out continuously. However, precise observations of forcings and feedbacks will also be able to provide valuable conclusions on shorter time scales. For example, knowledge of the climate forcing by increasing CFC's relative to the forcing by changing ozone is important to policymakers, as is information on the forcing by CO2 relative to the forcing by sulfate aerosols. It will also be possible to obtain valuable tests of climate models on short time scales, if there is precise monitoring of all forcings and feedbacks during and after events such as a large volcanic eruption

  20. Learning culture and feedback: an international study of medical athletes and musicians.

    Science.gov (United States)

    Watling, Christopher; Driessen, Erik; van der Vleuten, Cees P M; Lingard, Lorelei

    2014-07-01

    Feedback should facilitate learning, but within medical education it often fails to deliver on its promise. To better understand why feedback is challenging, we explored the unique perspectives of doctors who had also trained extensively in sport or music, aiming to: (i) distinguish the elements of the response to feedback that are determined by the individual learner from those determined by the learning culture, and (ii) understand how these elements interact in order to make recommendations for improving feedback in medical education. Using a constructivist grounded theory approach, we conducted semi-structured interviews with 27 doctors or medical students who had high-level training and competitive or performance experience in sport (n = 15) or music (n = 12). Data were analysed iteratively using constant comparison. Key themes were identified and their relationships critically examined to derive a conceptual understanding of feedback and its impact. We identified three essential sources of influence on the meaning that feedback assumed: the individual learner; the characteristics of the feedback, and the learning culture. Individual learner traits, such as motivation and orientation toward feedback, appeared stable across learning contexts. Similarly, certain feedback characteristics, including specificity, credibility and actionability, were valued in sport, music and medicine alike. Learning culture influenced feedback in three ways: (i) by defining expectations for teachers and teacher-learner relationships; (ii) by establishing norms for and expectations of feedback, and (iii) by directing teachers' and learners' attention toward certain dimensions of performance. Learning culture therefore neither creates motivated learners nor defines 'good feedback'; rather, it creates the conditions and opportunities that allow good feedback to occur and learners to respond. An adequate understanding of feedback requires an integrated approach incorporating both

  1. Feedback-Driven Dynamic Invariant Discovery

    Science.gov (United States)

    Zhang, Lingming; Yang, Guowei; Rungta, Neha S.; Person, Suzette; Khurshid, Sarfraz

    2014-01-01

    Program invariants can help software developers identify program properties that must be preserved as the software evolves, however, formulating correct invariants can be challenging. In this work, we introduce iDiscovery, a technique which leverages symbolic execution to improve the quality of dynamically discovered invariants computed by Daikon. Candidate invariants generated by Daikon are synthesized into assertions and instrumented onto the program. The instrumented code is executed symbolically to generate new test cases that are fed back to Daikon to help further re ne the set of candidate invariants. This feedback loop is executed until a x-point is reached. To mitigate the cost of symbolic execution, we present optimizations to prune the symbolic state space and to reduce the complexity of the generated path conditions. We also leverage recent advances in constraint solution reuse techniques to avoid computing results for the same constraints across iterations. Experimental results show that iDiscovery converges to a set of higher quality invariants compared to the initial set of candidate invariants in a small number of iterations.

  2. Synchronous Databus Network in ITER: Open source real-time network for the next nuclear fusion experiment

    International Nuclear Information System (INIS)

    Boncagni, L.; Centioli, C.; Iannone, F.; Neri, C.; Panella, M.; Pangione, L.; Riva, M.; Scappaticci, M.; Vitale, V.; Zaccarian, L.

    2008-01-01

    The next nuclear fusion experiment, ITER, is providing the infrastructure for the optimal operation of a burning plasma, requiring feedback control of discharge parameters and on-line evaluation of computationally intensive models running in a cluster of controller nodes. Thus, the synchronization of the available information on the plasma and plant state variables among the controller nodes is a key issue for ITER. The ITER conceptual design aims to perform feedback control on a cluster of distributed controllers connected by a Synchronous Databus Network (SDN). Therefore it is mandatory to achieve a deterministic data exchange among the controller nodes with a refresh rate of at least 1 kHz and a jitter of at least 50 μs. Thus, a conservative estimate of the data flow within the controller network can be 3 kSample/ms. In this paper the open source RTnet project is evaluated to meet the requirements of the SDN of ITER. A testbed involving a cluster of eight nodes connected over a standard ethernet network has been set up to simulate a distributed real-time control system. The main goal of the test is to verify the compliance of the performance with the ITER SDN requirements

  3. Estimation of Graphite Dust Production in ITER TBM

    International Nuclear Information System (INIS)

    Kang, Ji Ho; Kim, Eung Seon

    2013-01-01

    This scheme uses simple equations and the calculation time is much less than others. However, the contact equation requires a specially tuned material properties and instability of system matrix were reported. Second, only a couple of pebbles were modeled using FEM(Finite Element Method) and appropriate boundary and loading conditions are imposed. This scheme gives a detailed information of stress distribution of the pebbles and the stability of calculation is well established. However, the calculation cost is fairly high and only a few pebble can be analyzed in detail at a time with specifically assigned contact conditions. In this study, a prediction model of graphite dust production in ITER(International Thermonuclear Experimental Reactor) TBM(Test Blanket Module) using FEM was introduced and the amount of dust production for an operation cycle was estimated. In this study, graphite dust generation in the reflector zone of ITER TBM was estimated using FE analysis. A unit-cell model was defined to simulate normal contact forces and slip distances on contact points between the center pebble and the surrounding pebbles. The dust production was calculated using Archard equation. The simulation was repeated with different friction coefficient of graphite material to investigate the effect of friction on the dust production. The calculation result showed that the amount of dust production was 2.22∼3.67e-4 g/m 3 which was almost linearly proportional to the friction coefficient of graphite material. The amount of graphite dust production was considered too much small for a dust explosion

  4. Selective enhancement of orientation tuning before saccades.

    Science.gov (United States)

    Ohl, Sven; Kuper, Clara; Rolfs, Martin

    2017-11-01

    Saccadic eye movements cause a rapid sweep of the visual image across the retina and bring the saccade's target into high-acuity foveal vision. Even before saccade onset, visual processing is selectively prioritized at the saccade target. To determine how this presaccadic attention shift exerts its influence on visual selection, we compare the dynamics of perceptual tuning curves before movement onset at the saccade target and in the opposite hemifield. Participants monitored a 30-Hz sequence of randomly oriented gratings for a target orientation. Combining a reverse correlation technique previously used to study orientation tuning in neurons and general additive mixed modeling, we found that perceptual reports were tuned to the target orientation. The gain of orientation tuning increased markedly within the last 100 ms before saccade onset. In addition, we observed finer orientation tuning right before saccade onset. This increase in gain and tuning occurred at the saccade target location and was not observed at the incongruent location in the opposite hemifield. The present findings suggest, therefore, that presaccadic attention exerts its influence on vision in a spatially and feature-selective manner, enhancing performance and sharpening feature tuning at the future gaze location before the eyes start moving.

  5. Overview and status of ITER internal components

    International Nuclear Information System (INIS)

    Merola, Mario; Escourbiac, Frederic; Raffray, René; Chappuis, Philippe; Hirai, Takeshi; Martin, Alex

    2014-01-01

    Highlights: • Manufacturing technologies for the ITER internal components have been developed. • The Blanket System successfully went through its Final Design Review in April 2013. • The decision to start operation with a Divertor with a full-W armour has been taken. - Abstract: The internal components of ITER are one of the most design and technically challenging components of the ITER machine, and include the Blanket System and the Divertor. The Blanket System successfully went through its Final Design Review in April 2013 and now it is entering into the procurement phase. The design and qualification of the Divertor with a full-tungsten armour was successfully completed and this enabled the decision in November 2013 to start operation with this material option. This paper summarizes the engineering design, the R and D, the technology qualification and procurement status of the Blanket System and of the Divertor of the ITER machine

  6. Status and verification strategy for ITER neutronics

    Energy Technology Data Exchange (ETDEWEB)

    Loughlin, Michael, E-mail: michael.loughlin@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Angelone, Maurizio [Associazione EURATOM-ENEA Sulla Fusione, Via E. Fermi 45, I-00044 Frascati, Roma (Italy); Batistoni, Paola [Associazione EURATOM-ENEA Sulla Fusione, Via E. Fermi 45, I-00044 Frascati, Roma (Italy); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Bertalot, Luciano [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Eskhult, Jonas [Studsvik Nuclear AB, SE-611 Nyköping (Sweden); Konno, Chikara [Japan Atomic Energy Agency Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Pampin, Raul [F4E Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, Barcelona 08019 (Spain); Polevoi, Alexei; Polunovskiy, Eduard [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2014-10-15

    The paper summarizes the current status of neutronics at ITER and a first set of proposals for experimental programmes to be conducted in the early operational life-time of ITER are described for the more crucial areas. These include a TF coils heating benchmark, a streaming benchmark and streaming measurements by activation on ITER itself. Also on ITER the measurement of activated water from triton burn-up should be planned and performed. This will require the measurement of triton burn-up in DD phase. Measurements of neutron flux in the tokamak building during DD operations should also be carried out. The use of JET for verification of shut down dose rate estimates is desirable. Other facilities to examine the production and behaviour of activated corrosion products and the shielding properties of concretes to high energy (6 MeV) gamma-rays are recommended.

  7. Overview and status of ITER internal components

    Energy Technology Data Exchange (ETDEWEB)

    Merola, Mario, E-mail: mario.merola@iter.org; Escourbiac, Frederic; Raffray, René; Chappuis, Philippe; Hirai, Takeshi; Martin, Alex

    2014-10-15

    Highlights: • Manufacturing technologies for the ITER internal components have been developed. • The Blanket System successfully went through its Final Design Review in April 2013. • The decision to start operation with a Divertor with a full-W armour has been taken. - Abstract: The internal components of ITER are one of the most design and technically challenging components of the ITER machine, and include the Blanket System and the Divertor. The Blanket System successfully went through its Final Design Review in April 2013 and now it is entering into the procurement phase. The design and qualification of the Divertor with a full-tungsten armour was successfully completed and this enabled the decision in November 2013 to start operation with this material option. This paper summarizes the engineering design, the R and D, the technology qualification and procurement status of the Blanket System and of the Divertor of the ITER machine.

  8. On the safety of ITER accelerators.

    Science.gov (United States)

    Li, Ge

    2013-01-01

    Three 1 MV/40A accelerators in heating neutral beams (HNB) are on track to be implemented in the International Thermonuclear Experimental Reactor (ITER). ITER may produce 500 MWt of power by 2026 and may serve as a green energy roadmap for the world. They will generate -1 MV 1 h long-pulse ion beams to be neutralised for plasma heating. Due to frequently occurring vacuum sparking in the accelerators, the snubbers are used to limit the fault arc current to improve ITER safety. However, recent analyses of its reference design have raised concerns. General nonlinear transformer theory is developed for the snubber to unify the former snubbers' different design models with a clear mechanism. Satisfactory agreement between theory and tests indicates that scaling up to a 1 MV voltage may be possible. These results confirm the nonlinear process behind transformer theory and map out a reliable snubber design for a safer ITER.

  9. Eighth ITER negotiations meeting (N-8)

    International Nuclear Information System (INIS)

    Korzhavin, V.

    2003-01-01

    The eighth ITER Negotiations meeting was held on 18-19 February, 2003 in St. Petersburg, Russia. The delegations of People's Republic of China and the USA joined those from Canada, The European Union, Japan and the Russian federation in their efforts to reach agreement on the implementation of the ITER project. The delegations took note of the progress of discussions on procurement allocations, ITER decommissioning issues, management structure and intellectual property rights. The Negotiators approved the report on the Joint Assessment of Specific Sites and noted the report on the start of the ITER Transitional Arrangements (ITA). The delegations also noted that China has stated its willingness to participate in ITA and that the USA is considering participation

  10. Anderson Acceleration for Fixed-Point Iterations

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Homer F. [Worcester Polytechnic Institute, MA (United States)

    2015-08-31

    The purpose of this grant was to support research on acceleration methods for fixed-point iterations, with applications to computational frameworks and simulation problems that are of interest to DOE.

  11. The Physics Basis of ITER Confinement

    International Nuclear Information System (INIS)

    Wagner, F.

    2009-01-01

    ITER will be the first fusion reactor and the 50 year old dream of fusion scientists will become reality. The quality of magnetic confinement will decide about the success of ITER, directly in the form of the confinement time and indirectly because it decides about the plasma parameters and the fluxes, which cross the separatrix and have to be handled externally by technical means. This lecture portrays some of the basic principles which govern plasma confinement, uses dimensionless scaling to set the limits for the predictions for ITER, an approach which also shows the limitations of the predictions, and describes briefly the major characteristics and physics behind the H-mode--the preferred confinement regime of ITER.

  12. Iterative roots of homeomorphisms possessing periodic points

    Directory of Open Access Journals (Sweden)

    Paweł Solarz

    2007-06-01

    Full Text Available In this paper we give necessary and sufficient conditions for the existence of orientation-preserving iterative roots of a homeomorphism with a nonempty set of periodic points. We also give a construction method for these roots.

  13. Iterative Adaptive Sampling For Accurate Direct Illumination

    National Research Council Canada - National Science Library

    Donikian, Michael

    2004-01-01

    This thesis introduces a new multipass algorithm, Iterative Adaptive Sampling, for efficiently computing the direct illumination in scenes with many lights, including area lights that cause realistic soft shadows...

  14. Modeling defect trends for iterative development

    Science.gov (United States)

    Powell, J. D.; Spanguolo, J. N.

    2003-01-01

    The Employment of Defects (EoD) approach to measuring and analyzing defects seeks to identify and capture trends and phenomena that are critical to managing software quality in the iterative software development lifecycle at JPL.

  15. Accountability and feedback, part IV: destructive feedback.

    Science.gov (United States)

    Harolds, Jay A

    2013-04-01

    There are times that feedback is destructive rather than helpful to the employee and the organization. Occasionally, this is deliberate, such as when a boss does not like someone for reasons that have nothing to do with his/her performance as an employee, or his/her character. More often, it is inadvertent. This could be due to erroneous information from others or the leader's failure to take the time to adequately observe or supervise others. It could also be due to a lack of understanding of the individual's communication style, or failure to take into account age, cultural, religious, or sex differences. This article addresses some of these issues and what to do about it.

  16. Closed-loop torque feedback for a universal field-oriented controller

    Science.gov (United States)

    De Doncker, R.W.A.A.; King, R.D.; Sanza, P.C.; Haefner, K.B.

    1992-11-24

    A torque feedback system is employed in a universal field-oriented (UFO) controller to tune a torque-producing current command and a slip frequency command in order to achieve robust torque control of an induction machine even in the event of current regulator errors and during transitions between pulse width modulated (PWM) and square wave modes of operation. 1 figure.

  17. Iterative Development of an Online Dietary Recall Tool: INTAKE24.

    Science.gov (United States)

    Simpson, Emma; Bradley, Jennifer; Poliakov, Ivan; Jackson, Dan; Olivier, Patrick; Adamson, Ashley J; Foster, Emma

    2017-02-09

    Collecting large-scale population data on dietary intake is challenging, particularly when resources and funding are constrained. Technology offers the potential to develop novel ways of collecting large amounts of dietary information while making it easier, more convenient, intuitive, and engaging for users. INTAKE24 is an online multiple pass 24 h dietary recall tool developed for use in national food and nutrition surveys. The development of INTAKE24 was a four-stage iterative process of user interaction and evaluation with the intended end users, 11-24 years old. A total of 80 11-24 years old took part in the evaluation, 20 at each stage. Several methods were used to elicit feedback from the users including, 'think aloud', 'eye tracking', semi-structured interviews, and a system usability scale. Each participant completed an interviewer led recall post system completion. Key system developments generated from the user feedback included a 'flat' interface, which uses only a single interface screen shared between all of the various activities (e.g., free text entry, looking up foods in the database, portion size estimation). Improvements to the text entry, search functionality, and navigation around the system were also influenced through feedback from users at each stage. The time to complete a recall using INTAKE24 almost halved from the initial prototype to the end system, while the agreement with an interviewer led recall improved. Further developments include testing the use of INTAKE24 with older adults and translation into other languages for international use. Our future aim is to validate the system with recovery biomarkers.

  18. Iterative Development of an Online Dietary Recall Tool: INTAKE24

    Directory of Open Access Journals (Sweden)

    Emma Simpson

    2017-02-01

    Full Text Available Collecting large-scale population data on dietary intake is challenging, particularly when resources and funding are constrained. Technology offers the potential to develop novel ways of collecting large amounts of dietary information while making it easier, more convenient, intuitive, and engaging for users. INTAKE24 is an online multiple pass 24 h dietary recall tool developed for use in national food and nutrition surveys. The development of INTAKE24 was a four-stage iterative process of user interaction and evaluation with the intended end users, 11–24 years old. A total of 80 11–24 years old took part in the evaluation, 20 at each stage. Several methods were used to elicit feedback from the users including, ‘think aloud’, ‘eye tracking’, semi-structured interviews, and a system usability scale. Each participant completed an interviewer led recall post system completion. Key system developments generated from the user feedback included a ‘flat’ interface, which uses only a single interface screen shared between all of the various activities (e.g., free text entry, looking up foods in the database, portion size estimation. Improvements to the text entry, search functionality, and navigation around the system were also influenced through feedback from users at each stage. The time to complete a recall using INTAKE24 almost halved from the initial prototype to the end system, while the agreement with an interviewer led recall improved. Further developments include testing the use of INTAKE24 with older adults and translation into other languages for international use. Our future aim is to validate the system with recovery biomarkers.

  19. Linear ideal MHD stability calculations for ITER

    International Nuclear Information System (INIS)

    Hogan, J.T.

    1988-01-01

    A survey of MHD stability limits has been made to address issues arising from the MHD--poloidal field design task of the US ITER project. This is a summary report on the results obtained to date. The study evaluates the dependence of ballooning, Mercier and low-n ideal linear MHD stability on key system parameters to estimate overall MHD constraints for ITER. 17 refs., 27 figs

  20. ITER activities status report: December 1989

    International Nuclear Information System (INIS)

    1990-01-01

    Beginning in 1988 and continuing through 1990, the four Parties involved, under the auspices of the IAEA, have been cooperating in the ITER Conceptual Design Activities. This activity resulted in a single conceptual design for a facility that could achieve the objectives established for ITER. This report is an interim report which gives a brief summary of the Conceptual Design Activities through December, 1989. 4 figs, 1 tab

  1. ITER EDA Newsletter. V.4, no.1

    International Nuclear Information System (INIS)

    1995-01-01

    This ITER EDA (Engineering Design Activities) Newsletter issue reports on (i) the seventh ITER Council Meeting held at the Naka Joint Work Site on 14-15 December 1994, (ii) the ''Confinement Modelling and Database Expert Group Workshop'' held in Seville, Spain, 3-4 October 1994, and (iii) the first meeting of the International Organizing Committee for the Seventh International Fusion Reactor Materials Conference

  2. Overview and status of ITER Cryostat manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, Anil K., E-mail: anil.bhardwaj@iter-india.org [ITER-India, Institute For Plasma Research, A-29, GIDC Electronics Estate, Sector-25, Gandhinagar 382016 (India); Gupta, Girish; Prajapati, Rajnikant; Joshi, Vaibhav; Patel, Mitul; Bhavsar, Jagrut; More, Vipul; Jindal, Mukesh; Bhattacharya, Avik; Jogi, Gourav; Palaliya, Amit; Jha, Saroj; Pandey, Manish; Shukla, Dileep [ITER-India, Institute For Plasma Research, A-29, GIDC Electronics Estate, Sector-25, Gandhinagar 382016 (India); Iyer, Ganesh; Jadhav, Pandurang; Goyal, Dipesh; Desai, Anish [Larsen & Toubro Limited, Heavy Engineering, Hazira Manufacturing Complex, Gujarat (India); Sekachev, I.; Vitupier, Guillaume [ITER Organization, Route de Vinon sur Verdon – CS 90046, 13067 Saint Paul Lez Durance Cedex (France); and others

    2016-11-01

    Highlights: • Manufacturing status of one of the largest and the heaviest fully welded stainless steel vacuum chambers in the world (ITER Cryostat). • Overview of manufacturing stages and its segmentation. • Overview of manufacturing procedures and assembly and installation. - Abstract: One of ITER-India's commitments to the ITER Organization is procurement of the ITER Cryostat. It is a large vacuum vessel (∼29 m dia. and ∼29 m height), which is made up of 304/304 L dual marked stainless steel and has a total mass over 3500 t. The thickness of the vessel wall varies from 50 mm to 190 mm. It is one of the largest and the heaviest fully welded stainless steel vacuum chambers in the world which provides vacuum thermal insulation for the superconducting magnets operating at 4.5 K and for the thermal shield operating at 80 K. It also mechanically supports the magnet system along with the vacuum vessel (VV). The cryostat is designed and constructed according to ASME Section-VIII Division-2 with additional ITER Vacuum Handbook requirements and it is classified as protection important component (PIC-2). Manufacturing of cryostat segments is ongoing in India; sub-assembly of four major sections of the cryostat from the segments will be done at the ITER site in a temporary workshop building and the final assembly will be done in the pit of the tokamak building, the final location. The cryostat manufacturing contract has been awarded to Larsen and Toubro Limited in August 2012 after completion of design [4] and signing of Procurement Arrangement [1] with ITER Organization. Manufacturing of the cryostat was started in January 2014 after approval of the manufacturing drawings and procedures. The temporary workshop of 44 m × 110 m × 26 m in height has been completed in November 2014 at the ITER site with a 200 t crane installed. This paper gives an overview and the status of the cryostat manufacturing.

  3. Gyrokinetic Simulations of the ITER Pedestal

    Science.gov (United States)

    Kotschenreuther, Mike

    2015-11-01

    It has been reported that low collisionality pedestals for JET parameters are strongly stable to Kinetic Ballooning Modes (KBM), and it is, as simulations with GENE show, the drift-tearing modes that produce the pedestal transport. It would seem, then, that gyrokinetic simulations may be a powerful, perhaps, indispensable tool for probing the characteristics of the H-mode pedestal in ITER especially since projected ITER pedestals have the normalized gyroradius ρ* smaller than the range of present experimental investigation; they do lie, however, within the regime of validity of gyrokinetics. Since ExB shear becomes small as ρ* approaches zero, strong drift turbulence will eventually be excited. Finding an answer to the question whether the ITER ρ* is small enough to place it in the high turbulence regime compels serious investigation. We begin with MHD equilibria (including pedestal bootstrap current) constructed using VMEC. Plasma profile shapes, very close to JET experimental profiles, are scaled to values expected on ITER (e.g., a 4 keV pedestal). The equilibrium ExB shear is computed using a neoclassical formula for the radial electric field. As with JET, the ITER pedestal is found to be strongly stable to KBM. Preliminary nonlinear simulations with GENE show that the turbulent drift transport is strong for ITER; the electrostatic transport has a highly unfavorable scaling from JET to ITER, going from being highly sub-dominant to electromagnetic transport on JET, to dominant on ITER. At burning plasma parameters, pedestals in spherical tokamak H-modes may have much stronger velocity shear, and hence more favorable transport; preliminary investigations will be reported. This research supported by U.S. Department of Energy, Office of Fusion Energy Science: Grant No. DE-FG02-04ER-54742.

  4. ITER EDA Newsletter. V. 3, no. 11

    International Nuclear Information System (INIS)

    1994-11-01

    This ITER EDA (Engineering Design Activities) Newsletter issue reports on (i) the third Technical Meeting on Safety and Environment held at the San Diego Joint Work Site, October 10-14, 1994; (ii) the ITER Expert Group Meeting on Disruptions, Plasma Control and MHD, held in Seville, Spain, September 29-30, 1994; in addition to a brief contribution on aspects of family life for foreigners at the Naka Joint Work Site

  5. ITER EDA Newsletter. V. 6, no. 5

    International Nuclear Information System (INIS)

    1997-05-01

    This issue of the newsletter on Engineering Design Activities (EDA) for the ITER Tokamak project contains a report on Second International Industries' Liaison meeting which was held in Tokyo on 2-4 April 1997 (by Y. Kaneki, JAIF, Japan); an overview report on the Blanket project (by A. Cardella, I.Ioki (ITER Central Team), W. Daenner (EU Home Team)); and a progress report on microwave reflectometry (by J. Sanchez, Madrid, Spain)

  6. ITER EDA newsletter. V. 8, no. 10

    International Nuclear Information System (INIS)

    1999-10-01

    This ITER EDA Newsletter contains summary reports on the seventh meeting of the ITER physics expert group on energetic particles, heating and steady state operations in Frascati, Italy, on the fifth international symposium on fusion nuclear technology in Rome, Italy and on the IAEA technical committee meeting on electron cyclotron resonance heating physics and technology for fusion devices in Oh-arai, Japan. Individual abstracts are prepared for the three contributions

  7. Overview and status of ITER Cryostat manufacturing

    International Nuclear Information System (INIS)

    Bhardwaj, Anil K.; Gupta, Girish; Prajapati, Rajnikant; Joshi, Vaibhav; Patel, Mitul; Bhavsar, Jagrut; More, Vipul; Jindal, Mukesh; Bhattacharya, Avik; Jogi, Gourav; Palaliya, Amit; Jha, Saroj; Pandey, Manish; Shukla, Dileep; Iyer, Ganesh; Jadhav, Pandurang; Goyal, Dipesh; Desai, Anish; Sekachev, I.; Vitupier, Guillaume

    2016-01-01

    Highlights: • Manufacturing status of one of the largest and the heaviest fully welded stainless steel vacuum chambers in the world (ITER Cryostat). • Overview of manufacturing stages and its segmentation. • Overview of manufacturing procedures and assembly and installation. - Abstract: One of ITER-India's commitments to the ITER Organization is procurement of the ITER Cryostat. It is a large vacuum vessel (∼29 m dia. and ∼29 m height), which is made up of 304/304 L dual marked stainless steel and has a total mass over 3500 t. The thickness of the vessel wall varies from 50 mm to 190 mm. It is one of the largest and the heaviest fully welded stainless steel vacuum chambers in the world which provides vacuum thermal insulation for the superconducting magnets operating at 4.5 K and for the thermal shield operating at 80 K. It also mechanically supports the magnet system along with the vacuum vessel (VV). The cryostat is designed and constructed according to ASME Section-VIII Division-2 with additional ITER Vacuum Handbook requirements and it is classified as protection important component (PIC-2). Manufacturing of cryostat segments is ongoing in India; sub-assembly of four major sections of the cryostat from the segments will be done at the ITER site in a temporary workshop building and the final assembly will be done in the pit of the tokamak building, the final location. The cryostat manufacturing contract has been awarded to Larsen and Toubro Limited in August 2012 after completion of design [4] and signing of Procurement Arrangement [1] with ITER Organization. Manufacturing of the cryostat was started in January 2014 after approval of the manufacturing drawings and procedures. The temporary workshop of 44 m × 110 m × 26 m in height has been completed in November 2014 at the ITER site with a 200 t crane installed. This paper gives an overview and the status of the cryostat manufacturing.

  8. ITER EDA Newsletter. V. 3, no. 12

    International Nuclear Information System (INIS)

    1994-12-01

    This ITER EDA (Engineering Design Activities) Newsletter issue reports on (i) the seventh Meeting of the Technical Advisory Committee (TAC-7) held at the Joint Work Site in Naka, Japan, 5-7 December 1994; (ii) the seventh Meeting of the ITER Management Advisory Committee (MAC-7) held at the Naka Joint Work Site, November 30 - December 1, 1994; (iii) the Magnet Technical Meeting, held at the Naka Joint Work Site on November 8-11, 1994

  9. ITER EDA newsletter. V. 7, no. 11

    International Nuclear Information System (INIS)

    1998-11-01

    This ITER EDA Newsletter contains a report on the delivery of the outer module of the CS model coil to Naka by K. Okuno et al, a special lecture by H. Yoshikawa, the president of the Science Council of Japan on the future outlook of nuclear fusion and a report on an ITER display during the 17th IAEA Fusion Energy Conference, held in Yokohama, Japan, from October 19 to 24, 1998

  10. Microphysics and Southern Ocean Cloud Feedback

    Science.gov (United States)

    McCoy, Daniel T.

    Global climate models (GCMs) change their cloud properties in the Southern Ocean (SO) with warming in a qualitatively consistent fashion. Cloud albedo increases in the mid-latitudes and cloud fraction decreases in the subtropics. This creates a distinctive 'dipole' structure in the SW cloud feedback. However, the shape of the dipole varies from model to model. In this thesis we discuss the microphysical mechanisms underlying the SW cloud feedback over the mid-latitude SO. We will focus on the negative lobe of the dipole. The negative SW cloud feedback in the mid-latitudes is created by transitions from ice to liquid in models. If ice transitions to liquid in mixed-phase clouds the cloud albedo increases because ice crystals are larger than liquid droplets and therefore more reflective for a constant mass of water. Decreases in precipitation efficiency further enhance this effect by decreasing sinks of cloud water. This transition is dependent on the mixed-phase cloud parameterization. Parameterizations vary wildly between models and GCMs disagree by up to 35 K on the temperature where ice and liquid are equally prevalent. This results in a wide spread in the model predictions of the increase in liquid water path (LWP, where the path is the vertically integrated mass of water) with warming that drives the negative optical depth cloud feedback. It is found that this disagreement also results in a wide array of climate mean-states as models that create liquid at lower temperatures have a higher mean-state LWP, lower ice water path (IWP), and higher condensed (ice and liquid) water path (CWP). This presents a problem in climate models. GCMs need to have a reasonable planetary albedo in their climate mean-state. We show evidence that GCMs have tuned cloud fraction to compensate for the variation in mid-latitude cloud albedo driven by the mixed-phase cloud parameterization. This tuning results in mid-latitude clouds that are both too few and too bright as well as a

  11. Parallel S/sub n/ iteration schemes

    International Nuclear Information System (INIS)

    Wienke, B.R.; Hiromoto, R.E.

    1986-01-01

    The iterative, multigroup, discrete ordinates (S/sub n/) technique for solving the linear transport equation enjoys widespread usage and appeal. Serial iteration schemes and numerical algorithms developed over the years provide a timely framework for parallel extension. On the Denelcor HEP, the authors investigate three parallel iteration schemes for solving the one-dimensional S/sub n/ transport equation. The multigroup representation and serial iteration methods are also reviewed. This analysis represents a first attempt to extend serial S/sub n/ algorithms to parallel environments and provides good baseline estimates on ease of parallel implementation, relative algorithm efficiency, comparative speedup, and some future directions. The authors examine ordered and chaotic versions of these strategies, with and without concurrent rebalance and diffusion acceleration. Two strategies efficiently support high degrees of parallelization and appear to be robust parallel iteration techniques. The third strategy is a weaker parallel algorithm. Chaotic iteration, difficult to simulate on serial machines, holds promise and converges faster than ordered versions of the schemes. Actual parallel speedup and efficiency are high and payoff appears substantial

  12. ITER driver blanket, European Community design

    International Nuclear Information System (INIS)

    Simbolotti, G.; Zampaglione, V.; Ferrari, M.; Gallina, M.; Mazzone, G.; Nardi, C.; Petrizzi, L.; Rado, V.; Violante, V.; Daenner, W.; Lorenzetto, P.; Gierszewski, P.; Grattarola, M.; Rosatelli, F.; Secolo, F.; Zacchia, F.; Caira, M.; Sorabella, L.

    1993-01-01

    Depending on the final decision on the operation time of ITER (International Thermonuclear Experimental Reactor), the Driver Blanket might become a basic component of the machine with the main function of producing a significant fraction (close to 0.8) of the tritium required for the ITER operation, the remaining fraction being available from external supplies. The Driver Blanket is not required to provide reactor relevant performance in terms of tritium self-sufficiency. However, reactor relevant reliability and safety are mandatory requirements for this component in order not to significantly afftect the overall plant availability and to allow the ITER experimental program to be safely and successfully carried out. With the framework of the ITER Conceptual Design Activities (CDA, 1988-1990), a conceptual design of the ITER Driver Blanket has been carried out by ENEA Fusion Dept., in collaboration with ANSALDO S.p.A. and SRS S.r.l., and in close consultation with the NET Team and CFFTP (Canadian Fusion Fuels Technology Project). Such a design has been selected as EC (European Community) reference design for the ITER Driver Blanket. The status of the design at the end of CDA is reported in the present paper. (orig.)

  13. Status and plans for US ITER studies

    International Nuclear Information System (INIS)

    Doggett, J.N.

    1992-01-01

    The United States' participation in the International Thermonuclear Experimental Reactor (ITER) began in later 1987 when the initiative to start a cooperative program among the four Parties -- the Soviet Union, Japan, the European Community, and the United States -- was initiated. Participation then continued through the start of Joint Work in May 1988 until the conclusion of the Conceptual Design Activities (CDA) in December 1990. In the period between the conclusion of the CDA and the agreement to execute the Engineering Design Activities (EDA), the US ITER Home Team continued to do work on the design, executed additional research and development, and participated in the preparations for the EDA. Activities included one major design study on a High-Aspect-Ratio Design and input to the National ITER Technical Review, the ITER Steering Committee -- US, Special Working Group 1, and the Fusion Energy Advisory Committee's Panel 1. Research and development was continued in areas of work that were identified as critical-path elements by an international panel chartered by the four ITER Parties near the end of the CDA. I will describe the conclusion of the CDA and the interim US ITER activities and will give an indication of our involvement in the EDA

  14. Student perceptions of assessment and feedback in longitudinal integrated clerkships.

    Science.gov (United States)

    Bates, Joanna; Konkin, Jill; Suddards, Carol; Dobson, Sarah; Pratt, Dan

    2013-04-01

    This study was conducted to elucidate how the learning environment and the student-preceptor relationship influence student experiences of being assessed and receiving feedback on performance. Thus, we examined how long-term clinical clerkship placements influence students' experiences of and views about assessment and feedback. We took a constructivist grounded approach, using authentic assessment and communities of practice as sensitising concepts. We recruited and interviewed 13 students studying in longitudinal integrated clerkships across two medical schools and six settings, using a semi-structured interview framework. We used an iterative coding process to code the data and arrive at a coding framework and themes. Students valued the unstructured assessment and informal feedback that arose from clinical supervision, and the sense of progress derived from their increasing responsibility for patients and acceptance into the health care community. Three themes emerged from the data. Firstly, students characterised their assessment and feedback as integrated, developmental and longitudinal. They reported authenticity in the monitoring and feedback that arose from the day-to-day delivery of patient care with their preceptors. Secondly, students described supportive and caring relationships and a sense of safety. These enabled them to reflect on their strengths and weaknesses and to interpret critical feedback as supportive. Students developed similar relationships across the health care team. Thirdly, the long-term placement provided for multiple indicators of progress for students. Patient outcomes were perceived as representing direct feedback about students' development as doctors. Taking increasing responsibility for patients over time is an indicator to students of their increasing competence and contributes to the developing of a doctor identity. Clerkship students studying for extended periods in one environment with one preceptor perceive assessment and

  15. Development and control towards a parallel water hydraulic weld/cut robot for machining processes in ITER vacuum vessel

    International Nuclear Information System (INIS)

    Wu Huapeng; Handroos, Heikki; Pessi, Pekka; Kilkki, Juha; Jones, Lawrence

    2005-01-01

    This paper presents a special robot, able to carry out welding and machining processes from inside the ITER vacuum vessel (VV), consisting of a five degree-of-freedom parallel mechanism, mounted on a carriage driven by two electric motors on a rack. The kinematic design of the robot has been optimised for ITER access and a hydraulically actuated pre-prototype built. A hybrid controller is designed for the robot, including position, speed and pressure feedback loops to achieve high accuracy and high dynamic performances. Finally, the experimental tests are given and discussed

  16. Portfolio, refleksion og feedback

    DEFF Research Database (Denmark)

    Hansen, Jens Jørgen; Qvortrup, Ane; Christensen, Inger-Marie F.

    2017-01-01

    Denne leder definerer indledningsvist begrebet portfolio og gør rede for anvendelsesmuligheder i en uddannelseskontekst. Dernæst behandles portfoliometodens kvalitet og effekt for læring og undervisning og de centrale begreber refleksion, progression og feedback præsenteres og diskuteres. Herefter...

  17. Feedback i undervisningen

    DEFF Research Database (Denmark)

    Kirkegaard, Preben Olund

    2015-01-01

    undervisningsdifferentiering, feedback på læreprocesser, formativ og summativ evaluering, observationer og analyse af undervisning samt lærernes teamsamarbejde herom. Praktikken udgør et særligt læringsrum i læreruddannelsen. Samspillet mellem studerende, praktiklærere og undervisere giver den studerende en unik mulighed...

  18. The Endogenous Feedback Network

    DEFF Research Database (Denmark)

    Augustenborg, Claudia Carrara

    2010-01-01

    proposals, it will first be considered the extents of their reciprocal compatibility, tentatively shaping an integrated, theoretical profile of consciousness. A new theory, the Endogenous Feedback Network (EFN) will consequently be introduced which, beside being able to accommodate the main tenets...

  19. Report of the international symposium for ITER. 'Burning plasma science and technology on ITER'

    International Nuclear Information System (INIS)

    2002-10-01

    This report contains the presentations on the International Symposium for ITER, held on Jan. 24, 2002 on the occasion of the ITER Governmental Negotiations in Tokyo. This symposium is organized by Japan Atomic Energy Research Institute with the support of the Ministry of Education, Culture, Sports, Science and Technology (MEXT). The meaningful results were obtained through this symposium especially on new frontiers of science and technology brought by ITER, accelerated road maps towards realizing fusion energy, and portfolio of other fusion configurations from ITER. The 5 of the presented papers are indexed individually (J.P.N.)

  20. Domain Tuning of Bilingual Lexicons for MT

    National Research Council Canada - National Science Library

    Ayan, Necip F; Dorr, Bonnie; Kolak, Okan

    2003-01-01

    ... (in this case, Chinese) to English. Using automatically induced domain-specific, comparable documents and language-independent clustering, we apply domain-tuning techniques to a bilingual lexicon for downstream translation of the input...

  1. Dynamic Performance Tuning Supported by Program Specification

    Directory of Open Access Journals (Sweden)

    Eduardo César

    2002-01-01

    Full Text Available Performance analysis and tuning of parallel/distributed applications are very difficult tasks for non-expert programmers. It is necessary to provide tools that automatically carry out these tasks. These can be static tools that carry out the analysis on a post-mortem phase or can tune the application on the fly. Both kind of tools have their target applications. Static automatic analysis tools are suitable for stable application while dynamic tuning tools are more appropriate to applications with dynamic behaviour. In this paper, we describe KappaPi as an example of a static automatic performance analysis tool, and also a general environment based on parallel patterns for developing and dynamically tuning parallel/distributed applications.

  2. Learning and Tuning of Fuzzy Rules

    Science.gov (United States)

    Berenji, Hamid R.

    1997-01-01

    In this chapter, we review some of the current techniques for learning and tuning fuzzy rules. For clarity, we refer to the process of generating rules from data as the learning problem and distinguish it from tuning an already existing set of fuzzy rules. For learning, we touch on unsupervised learning techniques such as fuzzy c-means, fuzzy decision tree systems, fuzzy genetic algorithms, and linear fuzzy rules generation methods. For tuning, we discuss Jang's ANFIS architecture, Berenji-Khedkar's GARIC architecture and its extensions in GARIC-Q. We show that the hybrid techniques capable of learning and tuning fuzzy rules, such as CART-ANFIS, RNN-FLCS, and GARIC-RB, are desirable in development of a number of future intelligent systems.

  3. Decentralized Feedback Controllers for Exponential Stabilization of Hybrid Periodic Orbits: Application to Robotic Walking*

    Science.gov (United States)

    Hamed, Kaveh Akbari; Gregg, Robert D.

    2016-01-01

    This paper presents a systematic algorithm to design time-invariant decentralized feedback controllers to exponentially stabilize periodic orbits for a class of hybrid dynamical systems arising from bipedal walking. The algorithm assumes a class of parameterized and nonlinear decentralized feedback controllers which coordinate lower-dimensional hybrid subsystems based on a common phasing variable. The exponential stabilization problem is translated into an iterative sequence of optimization problems involving bilinear and linear matrix inequalities, which can be easily solved with available software packages. A set of sufficient conditions for the convergence of the iterative algorithm to a stabilizing decentralized feedback control solution is presented. The power of the algorithm is demonstrated by designing a set of local nonlinear controllers that cooperatively produce stable walking for a 3D autonomous biped with 9 degrees of freedom, 3 degrees of underactuation, and a decentralization scheme motivated by amputee locomotion with a transpelvic prosthetic leg. PMID:27990059

  4. Adaptive tuning of elasto-plastic damper

    DEFF Research Database (Denmark)

    Høgsberg, Jan Riess; Krenk, Steen

    2007-01-01

    Hysteretic dampers are frequency independent, and thereby otentially effective for several structural vibration modes, provided that the inherent amplitude dependence can be controlled. An adaptive tuning procedure is proposed, aiming at elimination of the amplitude dependence by adjusting...... technique, and maximization leads to an amplitude dependent expression for the optimal yield level. The amplitude is predicted from the most recent extremum of the damper response, and simultaneously used to adjust the yield level. Numerical examples demonstrate that the adaptive tuning procedure succeeds...

  5. What higher education students do with teacher feedback: Feedback ...

    African Journals Online (AJOL)

    Feedback research, therefore, suggests a causal relationship between teacher feedback practices during text production, student attitude and writing performance. However, a four-year longitudinal study conducted at a higher education institution monitoring student perceptions of written feedback on essay drafts found that ...

  6. Online feedback op schriftelijk werk: betere feedback in minder tijd.

    NARCIS (Netherlands)

    van den Berg, B.A.M.; van der Hulst, M.E.

    2015-01-01

    Feedback is a powerful teaching technic to raise students’ performance, provided that the feedback is informative on how to improve, is given in a timely manner and students have the opportunity to act upon it. Therefore, many institutions want their students to receive feedback on their performance

  7. Efferent feedback can explain many hearing phenomena

    Science.gov (United States)

    Holmes, W. Harvey; Flax, Matthew R.

    2015-12-01

    The mixed mode cochlear amplifier (MMCA) model was presented at the last Mechanics of Hearing workshop [4]. The MMCA consists principally of a nonlinear feedback loop formed when an efferent-controlled outer hair cell (OHC) is combined with the cochlear mechanics and the rest of the relevant neurobiology. Essential elements of this model are efferent control of the OHC motility and a delay in the feedback to the OHC. The input to the MMCA is the passive travelling wave. In the MMCA amplification is localized where both the neural and tuned mechanical systems meet in the Organ of Corti (OoC). The simplest model based on this idea is a nonlinear delay line resonator (DLR), which is mathematically described by a nonlinear delay-differential equation (DDE). This model predicts possible Hopf bifurcations and exhibits its most interesting behaviour when operating near a bifurcation. This contribution presents some simulation results using the DLR model. These show that various observed hearing phenomena can be accounted for by this model, at least qualitatively, including compression effects, two-tone suppression and some forms of otoacoustic emissions (OAEs).

  8. ITER ITA newsletter. No. 18, October-November-December 2004

    International Nuclear Information System (INIS)

    2004-12-01

    This issue of ITER ITA (ITER Transitional Arrangements) newsletter contains concise information about ITER related meetings, namely, the fourth preparatory meeting for ITER decision making, which was held at the IAEA Headquarters in Vienna on 9 November 2004 and the 20th IAEA Fusion Energy Conference, which was held on 1-6 November 2004 in Vilamoura, Portugal

  9. An optimal tuning strategy for tidal turbines

    Science.gov (United States)

    2016-01-01

    Tuning wind and tidal turbines is critical to maximizing their power output. Adopting a wind turbine tuning strategy of maximizing the output at any given time is shown to be an extremely poor strategy for large arrays of tidal turbines in channels. This ‘impatient-tuning strategy’ results in far lower power output, much higher structural loads and greater environmental impacts due to flow reduction than an existing ‘patient-tuning strategy’ which maximizes the power output averaged over the tidal cycle. This paper presents a ‘smart patient tuning strategy’, which can increase array output by up to 35% over the existing strategy. This smart strategy forgoes some power generation early in the half tidal cycle in order to allow stronger flows to develop later in the cycle. It extracts enough power from these stronger flows to produce more power from the cycle as a whole than the existing strategy. Surprisingly, the smart strategy can often extract more power without increasing maximum structural loads on the turbines, while also maintaining stronger flows along the channel. This paper also shows that, counterintuitively, for some tuning strategies imposing a cap on turbine power output to limit loads can increase a turbine’s average power output. PMID:27956870

  10. An optimal tuning strategy for tidal turbines.

    Science.gov (United States)

    Vennell, Ross

    2016-11-01

    Tuning wind and tidal turbines is critical to maximizing their power output. Adopting a wind turbine tuning strategy of maximizing the output at any given time is shown to be an extremely poor strategy for large arrays of tidal turbines in channels. This 'impatient-tuning strategy' results in far lower power output, much higher structural loads and greater environmental impacts due to flow reduction than an existing 'patient-tuning strategy' which maximizes the power output averaged over the tidal cycle. This paper presents a 'smart patient tuning strategy', which can increase array output by up to 35% over the existing strategy. This smart strategy forgoes some power generation early in the half tidal cycle in order to allow stronger flows to develop later in the cycle. It extracts enough power from these stronger flows to produce more power from the cycle as a whole than the existing strategy. Surprisingly, the smart strategy can often extract more power without increasing maximum structural loads on the turbines, while also maintaining stronger flows along the channel. This paper also shows that, counterintuitively, for some tuning strategies imposing a cap on turbine power output to limit loads can increase a turbine's average power output.

  11. PREFACE: Progress in the ITER Physics Basis

    Science.gov (United States)

    Ikeda, K.

    2007-06-01

    I would firstly like to congratulate all who have contributed to the preparation of the `Progress in the ITER Physics Basis' (PIPB) on its publication and express my deep appreciation of the hard work and commitment of the many scientists involved. With the signing of the ITER Joint Implementing Agreement in November 2006, the ITER Members have now established the framework for construction of the project, and the ITER Organization has begun work at Cadarache. The review of recent progress in the physics basis for burning plasma experiments encompassed by the PIPB will be a valuable resource for the project and, in particular, for the current Design Review. The ITER design has been derived from a physics basis developed through experimental, modelling and theoretical work on the properties of tokamak plasmas and, in particular, on studies of burning plasma physics. The `ITER Physics Basis' (IPB), published in 1999, has been the reference for the projection methodologies for the design of ITER, but the IPB also highlighted several key issues which needed to be resolved to provide a robust basis for ITER operation. In the intervening period scientists of the ITER Participant Teams have addressed these issues intensively. The International Tokamak Physics Activity (ITPA) has provided an excellent forum for scientists involved in these studies, focusing their work on the high priority physics issues for ITER. Significant progress has been made in many of the issues identified in the IPB and this progress is discussed in depth in the PIPB. In this respect, the publication of the PIPB symbolizes the strong interest and enthusiasm of the plasma physics community for the success of the ITER project, which we all recognize as one of the great scientific challenges of the 21st century. I wish to emphasize my appreciation of the work of the ITPA Coordinating Committee members, who are listed below. Their support and encouragement for the preparation of the PIPB were

  12. ITER ITA newsletter. No. 24, July 2005

    International Nuclear Information System (INIS)

    2005-08-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about the Ministerial Meeting on the ITER site selection (MMI-2) took place in Moscow, Russian Federation, on 28 June 2005. About one hundred participants from the Parties to the ITER Negotiations and the IAEA attended at the Meeting. Mr. A.Yu. Rumyantsev, Director of Rosatom, welcomed the participants and pointed out that the goal of the meeting was to resolve the most difficult issue: to select the site for implementation of the ITER project. Once this decision had been taken, one could expect a swift and successful accomplishment of negotiations and beginning of work on the ITER constriction. Mr. A. Yu. Rumyantsev, Director of Rosatom, welcomed the participants and pointed out that the goal of the meeting was to resolve the most difficult issue: to select the site for implementation of the ITER project. Once this decision had been taken, one could expect a swift and successful accomplishment of negotiations and beginning of work on the ITER construction. Mr. Rumyantsev invited the Heads of Delegations of Japan, the European Union, the People's Republic of China, the Republic of Korea and the United States of America to express the positions of their Parties on the choice of a site. Mr. N. Nakayama, Japanese Minister of Education, Culture, Sports, Science and Technology, recognized that three years had passed since the start of Negotiations on the site issue and that a consensus on the roles of the Host Party and the Non-Host Party had been reached. It was therefore not desirable that both Japan and the EU still advocate their own sites and allow the Negotiations to continue with no prospect of coming to a conclusion. So, considering that the ITER project should be started as soon as possible for the future benefit of humankind, that the six-Party-framework for implementing the ITER project should not be broken, that the ITER project starting smoothly will be a major

  13. Picard iteration converges faster than Mann iteration for a class of quasi-contractive operators

    Directory of Open Access Journals (Sweden)

    Vasile Berinde

    2004-06-01

    Full Text Available In the class of quasi-contractive operators satisfying Zamfirescu's conditions, the most used fixed point iterative methods, that is, the Picard, Mann, and Ishikawa iterations, are all known to be convergent to the unique fixed point. In this paper, the comparison of the first two methods with respect to their convergence rate is obtained.

  14. Convergence rates for an iteratively regularized Newton–Landweber iteration in Banach space

    International Nuclear Information System (INIS)

    Kaltenbacher, Barbara; Tomba, Ivan

    2013-01-01

    In this paper, we provide convergence and convergence rate results for a Newton-type method with a modified version of Landweber iteration as an inner iteration in a Banach space setting. Numerical experiments illustrate the performance of the method. (paper)

  15. U.S. Contributions to ITER

    International Nuclear Information System (INIS)

    Sauthoff, Ned R.

    2005-01-01

    The United States participates in the ITER project and program to enable the study of the science and technology of burning plasmas, a key programmatic element missing from the world fusion program. The 2003 U.S. decision to enter the ITER negotiations followed an extensive series of community and governmental reviews of the benefits, readiness, and approaches to the study of burning plasmas. This paper describes both the technical and the organizational preparations and plans for U.S. participation in the ITER construction activity: in-kind contributions, staff contributions, and cash contributions as well as supporting physics and technology research. Near-term technical activities focus on the completion of R and D and design and mitigation of risks in the areas of the central solenoid magnet, shield/blanket, diagnostics, ion cyclotron system, electron cyclotron system, pellet fueling system, vacuum system, tritium processing system, and conventional systems. Outside the project, the U .S. is engaged in preparations for the test blanket module program. Organizational activities focus on preparations of the project management arrangements to maximize the overall success of the ITER Project; elements include refinement of U.S. directions on the international arrangements, the establishment of the U.S. Domestic Agency, progress along the path of the U.S. Department of Energy's Project Management Order, and overall preparations for commencement of the fabrication of major items of equipment and for provision of staff and cash as specified in the upcoming ITER agreement

  16. Study of neutron spectrometers for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Kaellne, Jan

    2005-11-15

    A review is presented of the developments in the field of neutron emission spectrometry (NES) which is of relevance for identifying the role of NES diagnostics on ITER and selecting suitable instrumentation. Neutron spectrometers will be part of the ITER neutron diagnostic complement and this study makes a special effort to examine which performance characteristics the spectrometers should possess to provide the best burning plasma diagnostic information together with neutron cameras and neutron yield monitors. The performance of NES diagnostics is coupled to how much interface space can be provided which has lead to an interest to find compact instruments and their NES capabilities. This study assesses all known spectrometer types of potential interest for ITER and makes a ranking of their performance (as demonstrated or projected), which, in turn, are compared with ITER measurement requirements as a reference; the ratio of diagnostic performance to interface cost for different spectrometers is also discussed for different spectrometer types. The overall result of the study is an assessment of which diagnostic functions neutron measurements can provide in burning plasma fusion experiments on ITER and the role that NES can play depending on the category of instrument installed. Of special note is the result that much higher quality diagnostic information can be obtained from neutron measurements with total yield monitors, profile flux cameras and spectrometers when the synergy in the data is considered in the analysis and interpretation.

  17. Intelligent algorithm tuning PID method of function electrical stimulation using knee joint angle.

    Science.gov (United States)

    Qiu, Shuang; He, Feng; Tang, Jiabei; Xu, Jiapeng; Zhang, Lixin; Zhao, Xin; Qi, Hongzhi; Zhou, Peng; Cheng, Xiaoman; Wan, Baikun; Ming, Dong

    2014-01-01

    Functional electrical stimulation (FES) could restore motor functions for individuals with spinal cord injury (SCI). By applying electric current pulses, FES system could produce muscle contractions, generate joint torques, and thus, achieve joint movements automatically. Since the muscle system is highly nonlinear and time-varying, feedback control is quite necessary for precision control of the preset action. In the present study, we applied two methods (Proportional Integral Derivative (PID) controller based on Back Propagation (BP) neural network and that based on Genetic Algorithm (GA)), to control the knee joint angle for the FES system, while the traditional Ziegler-Nichols method was used in the control group for comparison. They were tested using a muscle model of the quadriceps. The results showed that intelligent algorithm tuning PID controller displayed superior performance than classic Ziegler-Nichols method with constant parameters. More particularly, PID controller tuned by BP neural network was superior on controlling precision to make the feedback signal track the desired trajectory whose error was less than 1.2°±0.16°, while GA-PID controller, seeking the optimal parameters from multipoint simultaneity, resulted in shortened delay in the response. Both strategies showed promise in application of intelligent algorithm tuning PID methods in FES system.

  18. Synaptic and intrinsic homeostasis cooperate to optimize single neuron response properties and tune integrator circuits

    Science.gov (United States)

    2016-01-01

    Homeostatic processes that provide negative feedback to regulate neuronal firing rate are essential for normal brain function, and observations suggest that multiple such processes may operate simultaneously in the same network. We pose two questions: why might a diversity of homeostatic pathways be necessary, and how can they operate in concert without opposing and undermining each other? To address these questions, we perform a computational and analytical study of cell-intrinsic homeostasis and synaptic homeostasis in single-neuron and recurrent circuit models. We demonstrate analytically and in simulation that when two such mechanisms are controlled on a long time scale by firing rate via simple and general feedback rules, they can robustly operate in tandem to tune the mean and variance of single neuron's firing rate to desired goals. This property allows the system to recover desired behavior after chronic changes in input statistics. We illustrate the power of this homeostatic tuning scheme by using it to regain high mutual information between neuronal input and output after major changes in input statistics. We then show that such dual homeostasis can be applied to tune the behavior of a neural integrator, a system that is notoriously sensitive to variation in parameters. These results are robust to variation in goals and model parameters. We argue that a set of homeostatic processes that appear to redundantly regulate mean firing rate may work together to control firing rate mean and variance and thus maintain performance in a parameter-sensitive task such as integration. PMID:27306675

  19. Electron cyclotron power management for control of neoclassical tearing modes in the ITER baseline scenario

    Science.gov (United States)

    Poli, F. M.; Fredrickson, E. D.; Henderson, M. A.; Kim, S.-H.; Bertelli, N.; Poli, E.; Farina, D.; Figini, L.

    2018-01-01

    Time-dependent simulations are used to evolve plasma discharges in combination with a modified Rutherford equation for calculation of neoclassical tearing mode (NTM) stability in response to electron cyclotron (EC) feedback control in ITER. The main application of this integrated approach is to support the development of control algorithms by analyzing the plasma response with physics-based models and to assess how uncertainties in the detection of the magnetic island and in the EC alignment affect the ability of the ITER EC system to fulfill its purpose. Simulations indicate that it is critical to detect the island as soon as possible, before its size exceeds the EC deposition width, and that maintaining alignment with the rational surface within half of the EC deposition width is needed for stabilization and suppression of the modes, especially in the case of modes with helicity (2, 1) . A broadening of the deposition profile, for example due to wave scattering by turbulence fluctuations or not well aligned beams, could even be favorable in the case of the (2, 1)- NTM, by relaxing an over-focussing of the EC beam and improving the stabilization at the mode onset. Pre-emptive control reduces the power needed for suppression and stabilization in the ITER baseline discharge to a maximum of 5 MW, which should be reserved and available to the upper launcher during the entire flattop phase. Assuming continuous triggering of NTMs, with pre-emptive control ITER would be still able to demonstrate a fusion gain of Q=10 .

  20. ITER ITA newsletter No. 30, April-May 2006

    International Nuclear Information System (INIS)

    2006-06-01

    This issue of ITER ITA (ITER transitional Arrangements) newsletter contains concise information about ITER related activities including visit of Kaname Ikeda, director general nominee, to Naka; the common message from 6th preparatory meeting for ITER decision making; the eighth ITER preparatory committee and leaders meeting; principal deputy director-general Norbert Holtkamp and recollections of Dr. Michael Roberts on the occasion of his retirement

  1. ITER ITA newsletter. No. 25, August-September-October 2005

    International Nuclear Information System (INIS)

    2005-12-01

    This issue of the ITER ITA (ITER transitional arrangements) newsletter contains concise information about two ITER related meetings including the tenth ITER Negotiations and related meetings held in the period 7-12 September 2005 at Cadarache, France, the ITER Divertor meeting, which was held in Genova, Italy on 26-28 October 2005, and information about the forty-ninth regular session of IAEA General Conference and eighth Scientific Forum, 26-30 September 2005, Vienna, Austria

  2. Engaging Students with Audio Feedback

    Science.gov (United States)

    Cann, Alan

    2014-01-01

    Students express widespread dissatisfaction with academic feedback. Teaching staff perceive a frequent lack of student engagement with written feedback, much of which goes uncollected or unread. Published evidence shows that audio feedback is highly acceptable to students but is underused. This paper explores methods to produce and deliver audio…

  3. Student Perceptions of Classroom Feedback

    Science.gov (United States)

    Gamlem, Siv M.; Smith, Kari

    2013-01-01

    Feedback to students has been identified as a key strategy in learning and teaching, but we know less about how feedback is understood by students. The purpose of this study is to gain more insight into lower secondary students' perceptions of when and how they find classroom feedback useful. This article draws on data generated through individual…

  4. Det ved vi om Feedback

    DEFF Research Database (Denmark)

    Christensen, Vibeke; Bærenholdt, Jørgen

    Præsentation af forskningsviden om feedback i forskellige personkonstellationer i undervisningen: Feedback fra lærer til elev, fra elever til lærer, fra elev til elev og elevens eget arbejde med feedback til sig selv. De præsenterede forskningsresultater er udvalgt dels inden for en kognitivistisk...

  5. A Journey towards Sustainable Feedback

    Science.gov (United States)

    Mutch, Allyson; Young, Charlotte; Davey, Tamzyn; Fitzgerald, Lisa

    2018-01-01

    Meeting students' expectations associated with the provision of feedback is a perennial challenge for tertiary education. Efforts to provide comprehensive, timely feedback within our own first year undergraduate public health courses have not always met students' expectations. In response, we sought to develop peer feedback activities to support…

  6. Polarization feedback laser stabilization

    Science.gov (United States)

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  7. Regenerative feedback resonant circuit

    Science.gov (United States)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  8. Sand Dune Albedo Feedback

    Directory of Open Access Journals (Sweden)

    Yosef Ashkenazy

    2018-02-01

    Full Text Available Sand dunes cover substantial parts of desert areas. Fully active dunes are bare, while fixed dunes are stabilized by vegetation and biogenic crust, and the dune activity is affected by the wind. Here we suggest the following atmosphere-sand dune feedback: spatial differences in the dunes’ vegetation and biogenic crust cover lead to differences in albedo as the albedo of bare sand is larger than that of vegetation and biogenic crust. This leads to a higher temperature over the vegetated area, resulting in air flow from the bare dune area to the vegetated dune area, thus increasing the wind activity over the vegetated dune area. In turn, this leads to enhanced stress on the vegetation and enhanced dune activity and thus to a decrease in vegetation. These changes in vegetation cover affect the surface albedo, leading to a change in wind activity. We examined this feedback using an atmospheric general circulation model, Weather Research and Forecasting (WRF, in selected regions of the northwestern Negev Desert and the Sahara/Sahel region, and we show that changes in surface albedo do indeed lead to significantly enhanced wind activity over the lower albedo region. We then incorporated this feedback into a simple vegetated dune model, showing that the multiple states associated with active and fixed dunes can be obtained for a larger range of parameters and that the stables states become more extreme (i.e., the fixed dune state becomes more vegetated and the active dune state becomes less vegetated.

  9. Positive feedback promotes oscillations in negative feedback loops.

    Science.gov (United States)

    Ananthasubramaniam, Bharath; Herzel, Hanspeter

    2014-01-01

    A simple three-component negative feedback loop is a recurring motif in biochemical oscillators. This motif oscillates as it has the three necessary ingredients for oscillations: a three-step delay, negative feedback, and nonlinearity in the loop. However, to oscillate, this motif under the common Goodwin formulation requires a high degree of cooperativity (a measure of nonlinearity) in the feedback that is biologically "unlikely." Moreover, this recurring negative feedback motif is commonly observed augmented by positive feedback interactions. Here we show that these positive feedback interactions promote oscillation at lower degrees of cooperativity, and we can thus unify several common kinetic mechanisms that facilitate oscillations, such as self-activation and Michaelis-Menten degradation. The positive feedback loops are most beneficial when acting on the shortest lived component, where they function by balancing the lifetimes of the different components. The benefits of multiple positive feedback interactions are cumulative for a majority of situations considered, when benefits are measured by the reduction in the cooperativity required to oscillate. These positive feedback motifs also allow oscillations with longer periods than that determined by the lifetimes of the components alone. We can therefore conjecture that these positive feedback loops have evolved to facilitate oscillations at lower, kinetically achievable, degrees of cooperativity. Finally, we discuss the implications of our conclusions on the mammalian molecular clock, a system modeled extensively based on the three-component negative feedback loop.

  10. Auto-tuning systems for J-PARC LINAC RF cavities

    International Nuclear Information System (INIS)

    Fang, Z.; Kobayashi, T.; Fukui, Y.; Futatsukawa, K.; Michizono, S.; Yamaguchi, S.; Anami, S.; Suzuki, H.; Sato, F.; Shinozaki, S.; Chishiro, E.

    2014-01-01

    The 400-MeV proton linear accelerator (LINAC) at the Japan Proton Accelerator Research Complex (J-PARC) consists of 324-MHz low-β and 972-MHz high-β accelerator sections. From October 2006 to May 2013, only the 324-MHz low-β accelerator section was in operation. From the summer of 2013 the J-PARC LINAC was upgraded by installing the 972-MHz high-β accelerator section, and the proton beam was successfully accelerated to 400 MeV in January 2014. Auto-tuning systems for the J-PARC LINAC RF cavities have been successfully developed. A first generation design, an auto-tuning system using a mechanical tuner controller, was developed and operated for the first 3 years. Then the second-generation auto-tuning system was developed using a new approach to the RF cavity warm-up process, and this was applied to the accelerator operation for the subsequent 4 years. During the RF cavity warm-up process in this system, the mechanical tuner is constantly fixed and the input RF frequency is automatically tuned to the cavity resonance frequency using the FPGA (Field-Programmable Gate Array) of the digital feedback RF control system. After the input power level reaches the required value, input RF frequency tuning is stopped and it is switched to the operation frequency. Then, the mechanical tuner control begins operation. This second-generation auto-tuning system was extremely effective for the 324-MHz cavity operation. However, if we apply this approach to the 972-MHz RF cavities, an interlock due to the RF cavity reflection amplitude occasionally occurs at the end of the warm-up process. In order to solve this problem a third generation novel auto-tuning system was successfully developed in December 2013 and applied to the operation of the J-PARC LINAC, including the 972-MHz ACS RF cavities. During the warm-up process both the mechanical tuner controller and the input RF frequency tuning are in operation, and good matching between the input RF frequency and the RF cavity is

  11. Automatic Parameter Tuning for the Morpheus Vehicle Using Particle Swarm Optimization

    Science.gov (United States)

    Birge, B.

    2013-01-01

    A high fidelity simulation using a PC based Trick framework has been developed for Johnson Space Center's Morpheus test bed flight vehicle. There is an iterative development loop of refining and testing the hardware, refining the software, comparing the software simulation to hardware performance and adjusting either or both the hardware and the simulation to extract the best performance from the hardware as well as the most realistic representation of the hardware from the software. A Particle Swarm Optimization (PSO) based technique has been developed that increases speed and accuracy of the iterative development cycle. Parameters in software can be automatically tuned to make the simulation match real world subsystem data from test flights. Special considerations for scale, linearity, discontinuities, can be all but ignored with this technique, allowing fast turnaround both for simulation tune up to match hardware changes as well as during the test and validation phase to help identify hardware issues. Software models with insufficient control authority to match hardware test data can be immediately identified and using this technique requires very little to no specialized knowledge of optimization, freeing model developers to concentrate on spacecraft engineering. Integration of the PSO into the Morpheus development cycle will be discussed as well as a case study highlighting the tool's effectiveness.

  12. Physics basis of ITER-FEAT

    International Nuclear Information System (INIS)

    Shimada, M.; Campbell, D.J.; Wakatani, M.; Ninomiya, H.; Ivanov, N.V.; Mukhovatov, V.

    2001-01-01

    This paper reviews Physics R and D results obtained since the publication of the ITER Physics Basis document. The heating power required for the LH transition has been re-assessed, including recent results from C-Mod and JT-60U and it has been found that the predicted power is a factor of two lower than the previous projection. For predicting ITER-FEAT performance, a conservative scaling IPB98(y,2) has been adopted for the energy confinement, producing confinement times ∼20% lower than those derived from the IPB98(y,1) law. While energy confinement degradation at high density remains a serious issue, recent experiments suggest that good confinement is achievable in ITER at n/n G ∼0.85 with high triangularity. The estimated runaway electron energy has been reduced to ∼20MJ, since recent experiments show that runaway electrons disappear for q 95 leq2. (author)

  13. ITER Fast Ion Collective Thomson Scattering

    DEFF Research Database (Denmark)

    Bindslev, Henrik; Larsen, Axel Wright; Meo, Fernando

    2005-01-01

    The EFDA Contract 04-1213 with Risø National Laboratory concerning a detailed integrated design of a Fast Ion Collective Thomson Scattering (CTS) diagnostic for ITER was signed on 31 December 2004. In 2003 the Risø CTS group finished a feasibility study and a conceptual design of an ITER Fast Ion...... Collective Thomson Scattering System (Contract 01.654) [1, 2]. The purpose of the CTS diagnostic is to measure the distribution function of fast ions in the plasma. The feasibility study demonstrated that the only system that can fully meet the ITER measurement requirements for confined fusion alphas is a 60...... GHz system. The study showed that with two powerful microwave sources of this frequency (gyrotron) and two antenna systems, one on the low field side (LFS) and one on the high field side (HFS), it should be possible to resolve the distribution function of fast ions both for perpendicular and parallel...

  14. Re-starting an Arnoldi iteration

    Energy Technology Data Exchange (ETDEWEB)

    Lehoucq, R.B. [Argonne National Lab., IL (United States)

    1996-12-31

    The Arnoldi iteration is an efficient procedure for approximating a subset of the eigensystem of a large sparse n x n matrix A. The iteration produces a partial orthogonal reduction of A into an upper Hessenberg matrix H{sub m} of order m. The eigenvalues of this small matrix H{sub m} are used to approximate a subset of the eigenvalues of the large matrix A. The eigenvalues of H{sub m} improve as estimates to those of A as m increases. Unfortunately, so does the cost and storage of the reduction. The idea of re-starting the Arnoldi iteration is motivated by the prohibitive cost associated with building a large factorization.

  15. Status of the ITER vacuum vessel construction

    Energy Technology Data Exchange (ETDEWEB)

    Choi, C.H.; Sborchia, C.; Ioki, K.; Giraud, B.; Utin, Yu.; Sa, J.W. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Wang, X., E-mail: xiaoyuwww@gmail.com [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Teissier, P.; Martinez, J.M.; Le Barbier, R.; Jun, C.; Dani, S.; Barabash, V.; Vertongen, P.; Alekseev, A. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Jucker, P.; Bayon, A. [F4E, c/ Josep Pla, n. 2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Pathak, H.; Raval, J. [ITER-India, IPR, A-29, Electronics Estate, GIDC, Sector-25, Gandhinagar 382025 (India); Ahn, H.J. [ITER Korea, National Fusion Research Institute, Daejeon (Korea, Republic of); and others

    2014-10-15

    Highlights: • Final design of the ITER vacuum vessel (VV). • Procurement of the ITER VV. • Manufacturing results of real scale mock-ups. • Manufacturing status of the VV in domestic agencies. - Abstract: The ITER vacuum vessel (VV) is under manufacturing by four domestic agencies after completion of engineering designs that have been approved by the Agreed Notified Body (ANB). Manufacturing designs of the VV have been being completed, component by component, by accommodating requirements of the RCC-MR 2007 edition. Manufacturing of the VV first sector has been started in February 2012 in Korea and in-wall shielding in May 2013 in India. EU will start manufacturing of its first sector from September 2013 and Russia the upper port by the end of 2013. All DAs have manufactured several mock-ups including real-size ones to justify/qualify and establish manufacturing techniques and procedures.

  16. Regarding overrelaxation for accelerating an iteration process

    International Nuclear Information System (INIS)

    Vondy, D.R.

    1984-06-01

    The solution for a vector that satisfies a set of coupled equations is often obtained economically in iteration. Application of an overrelaxation coefficient to augment the calculated iterate changes is done to accelerate the rate of convergence. This scheme is simple to implement and often effective. Much is known theoretically about the iterative behavior when the system of equations is linear, although there are complexities that are not widely known. Extensive use is made of the scheme even to non-linear systems of equations where behavior depends on the situation. Of much concern to the developer of solution methods (typically an engineer or applied mathematician) is implementing an effective procedure at a modest investment in development and testing. Applications are described to thermal cell and neutron diffusion modeling

  17. Selection of plasma facing materials for ITER

    International Nuclear Information System (INIS)

    Ulrickson, M.; Barabash, V.; Chiocchio, S.

    1996-01-01

    ITER will be the first tokamak having long pulse operation using deuterium-tritium fuel. The problem of designing heat removal structures for steady state in a neutron environment is a major technical goal for the ITER Engineering Design Activity (EDA). The steady state heat flux specified for divertor components is 5 MW/m 2 for normal operation with transients to 15 MW/m 2 for up to 10 s. The selection of materials for plasma facing components is one of the major research activities. Three materials are being considered for the divertor; carbon fiber composites, beryllium, and tungsten. This paper discusses the relative advantages and disadvantages of these materials. The final section of plasma facing materials for the ITER divertor will not be made until the end of the EDA

  18. ITER EDA newsletter. V. 10, no. 4

    International Nuclear Information System (INIS)

    2001-04-01

    This ITER EDA Newsletter presents an overview of the Fourteenth Meeting of the ITER Physics Expert Group on Diagnostics which was held at the Institute for Plasma Physics, Juelich, Germany, 21-23 March 2001. The summary of the Meeting covers the discussions of the Expert Group as well as developments reported on similar meetings concerning ongoing work in diagnostic design and ITER relevant diagnostic development work which took place nearly at the same time. In addition, the outline of the material treated at the International Workshop on the Confinement Database and Modelling Expert Group in collaboration with the Edge and Pedestal Physics Expert Group which was held on 2-6 April 2001 at the Plasma Physics Research Centre of Lausanne (CRPP) Switzerland is presented

  19. ITER Experts' meeting on density limits

    International Nuclear Information System (INIS)

    Borrass, K.; Igitkhanov, Y.L.; Uckan, N.A.

    1989-12-01

    The necessity of achieving a prescribed wall load or fusion power essentially determines the plasma pressure in a device like ITER. The range of operation densities and temperatures compatible with this condition is constrained by the problems of power exhaust and the disruptive density limit. The maximum allowable heat loads on the divertor plates and the maximum allowable sheath edge temperature practically impose a lower limit on the operating densities, whereas the disruptive density limit imposes an upper limit. For most of the density limit scalings proposed in the past an overlap of the two constraints or at best a very narrow accessible density range is predicted for ITER. Improved understanding of the underlying mechanisms is therefore a crucial issue in order to provide a more reliable basis for extrapolation to ITER and to identify possible ways of alleviating the problem

  20. Burning plasmas in ITER for energy source

    International Nuclear Information System (INIS)

    Inoue, Nobuyuki

    2002-01-01

    Fusion research and development has two aspects. One is an academic research on science and technology, i.e., discovery and understanding of unexpected phenomena and, development of innovative technology, respectively. The other is energy source development to realize fusion as a viable energy future. Fusion research has been made remarkable progress in the past several decades, and ITER will soon realize burning plasma that is essential for both academic research and energy development. With ITER, scientific research on unknown phenomena such as self-organization of the plasma in burning state will become possible and it contributes to create a variety of academic outcome. Fusion researchers will have a responsibility to generate actual energy, and electricity generation immediately after the success of burning plasma control experiment in ITER is the next important step that has to be discussed seriously. (author)