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Sample records for positive control docking

  1. Guidance and Control of Position and Attitude for Rendezvous and Dock/Berthing with a Noncooperative/Target Spacecraft

    Directory of Open Access Journals (Sweden)

    Gilberto Arantes

    2014-01-01

    Full Text Available Noncooperative target spacecrafts are those assets in orbit that cannot convey any information about their states (position, attitude, and velocities or facilitate rendezvous and docking/berthing (RVD/B process. Designing a guidance, navigation, and control (GNC module for the chaser in a RVD/B mission with noncooperative target should be inevitably solved for on-orbit servicing technologies. The proximity operations and the guidance for achieving rendezvous problems are addressed in this paper. The out-of-plane maneuvers of proximity operations are explored with distinct subphases, including a chaser far approach in the target’s orbit to the first hold point and a closer approach to the final berthing location. Accordingly, guidance solutions are chosen for each subphase from the standard Hill based Closhessy-Willtshire (CW solution, elliptical fly-around, and Glideslope algorithms. The control is based on a linear quadratic regulator approach (LQR. At the final berthing location, attitude tracker based on a proportional derivative (PD form is tested to synchronize the chaser and target attitudes. The paper analyzes the performance of both controllers in terms of the tracking ability and the robustness. Finally, it prescribes any restrictions that may be imposed on the guidance during any subphase which can help to improve the controllers tracking ability.

  2. Automated waste canister docking and emplacement using a sensor-based intelligent controller

    International Nuclear Information System (INIS)

    Drotning, W.D.

    1992-08-01

    A sensor-based intelligent control system is described that utilizes a multiple degree-of-freedom robotic system for the automated remote manipulation and precision docking of large payloads such as waste canisters. Computer vision and ultrasonic proximity sensing are used to control the automated precision docking of a large object with a passive target cavity. Real-time sensor processing and model-based analysis are used to control payload position to a precision of ± 0.5 millimeter

  3. Autonomous docking control of visual-servo type underwater vehicle system aiming at underwater automatic charging

    International Nuclear Information System (INIS)

    Yanou, Akira; Ohnishi, Shota; Ishiyama, Shintaro; Minami, Mamoru

    2015-01-01

    A visual-servo type remotely operated vehicle (ROV) system with binocular wide-angle lens was developed to survey submarine resources, decontaminate radiation from mud in dam lake and so on. This paper explores the experiments on regulator performance and underwater docking of the robot system utilizing Genetic Algorithm (GA) for real-time recognition of the robot's relative position and posture through 3D marker. The visual servoing performances have been verified as follows; (1) The stability performances of the proposed regulator system have been evaluated by exerting abrupt distrubane force while the ROV is controlled by visual servoing. (2) The proposed system can track time-variant desired target position in x-axis (front-back direction of the robot). (3) The underwater docking can be completed by switching visual servoing and docking modes based on the error threshold, and by giving time-varying desired target position and orientation to the controller as a desired pose. (author)

  4. Robotics in hostile environment I. S. I. S. robot - automatic positioning and docking with proximity and force feed back sensors

    Energy Technology Data Exchange (ETDEWEB)

    Gery, D

    1987-01-01

    Recent improvements in control command systems and the development of tactile proximity and force feed back sensors make it possible to robotize complex inspection and maintenance operations in hostile environment, which could have not been possible by classical remotely operated manipulators. We describe the I.S.I.S. robot characteristics, the control command system software principles and the tactile and force-torque sensors which have been developed for the different sequences of an hostile environment inspection and repair: access trajectories generation with obstacles shunning, final positioning and docking using parametric algorithms taking into account measurement of the end of arm proximity and force-torque sensors.

  5. Robust adaptive backstepping neural networks control for spacecraft rendezvous and docking with input saturation.

    Science.gov (United States)

    Xia, Kewei; Huo, Wei

    2016-05-01

    This paper presents a robust adaptive neural networks control strategy for spacecraft rendezvous and docking with the coupled position and attitude dynamics under input saturation. Backstepping technique is applied to design a relative attitude controller and a relative position controller, respectively. The dynamics uncertainties are approximated by radial basis function neural networks (RBFNNs). A novel switching controller consists of an adaptive neural networks controller dominating in its active region combined with an extra robust controller to avoid invalidation of the RBFNNs destroying stability of the system outside the neural active region. An auxiliary signal is introduced to compensate the input saturation with anti-windup technique, and a command filter is employed to approximate derivative of the virtual control in the backstepping procedure. Globally uniformly ultimately bounded of the relative states is proved via Lyapunov theory. Simulation example demonstrates effectiveness of the proposed control scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Control rod position control device

    International Nuclear Information System (INIS)

    Ubukata, Shinji.

    1997-01-01

    The present invention provides a control rod position control device which stores data such as of position signals and driving control rod instruction before and after occurrence of abnormality in control for the control rod position for controlling reactor power and utilized the data effectively for investigating the cause of abnormality. Namely, a plurality of individual control devices have an operation mismatching detection circuit for outputting signals when difference is caused between a driving instruction given to the control rod position control device and the control rod driving means and signals from a detection means for detecting an actual moving amount. A general control device collectively controls the individual control devices. In addition, there is also disposed a position storing circuit for storing position signals at least before and after the occurrence of the control rod operation mismatching. With such procedures, the cause of the abnormality can be determined based on the position signals before and after the occurrence of control rod mismatching operation stored in the position storing circuit. Accordingly, the abnormality cause can be determined to conduct restoration in an early stage. (I.S.)

  7. Cooperative Rendezvous and Docking for Underwater Robots Using Model Predictive Control and Dual Decomposition

    DEFF Research Database (Denmark)

    Nielsen, Mikkel Cornelius; Johansen, Tor Arne; Blanke, Mogens

    2018-01-01

    This paper considers the problem of rendezvous and docking with visual constraints in the context of underwater robots with camera-based navigation. The objective is the convergence of the vehicles to a common point while maintaining visual contact. The proposed solution includes the design of a ...... of a distributed model predictive controller based on dual decomposition, which allows for optimization in a decentralized fashion. The proposed distributed controller enables rendezvous and docking between vehicles while maintaining visual contact....

  8. Plasma position control device

    International Nuclear Information System (INIS)

    Takase, Haruhiko.

    1987-01-01

    Purpose: To conduct position control stably to various plasmas and reduce the burden on the control coil power source. Constitution: Among the proportional, integration and differentiation controls, a proportional-differentiation control section and an integration control section are connected in parallel. Then, a signal switching circuit is disposed to the control signal input section for the proportional-differentiation control section such that either a present position of plasmas or deviation between the present plasma position and an aimed value can be selected as a control signal depending on the control procedures or the state of the plasmas. For instance, if a rapid response is required for the control, the deviation between the present plasma position and the aimed value is selected as the input signal to conduct proportional, integration and differentiation controls. While on the other hand, if it is intended to reduce the burden on the control coil power source, it is adapted such that the control signal inputted to the proportional-differentiation control section itself can select the present plasma position. (Yoshihara, H.)

  9. Logistics and operations implications of manual control of spacecraft docking maneuvers

    Science.gov (United States)

    Brody, Adam R.; Ellis, Stephen R.

    1991-01-01

    The implications of logistics and operations on the manual control of spacecraft docking are discussed. The results of simulation studies to investigate fuel and time cost tradeoffs are reviewed and discussed. Comparisons of acceleration control and pulse control are presented to evaluate the effects of astronauts being instructed to use pulse mode for fuel conservation. The applications of the findings to moon and Mars missions are addressed.

  10. Implementation of Statistical Process Control: Evaluating the Mechanical Performance of a Candidate Silicone Elastomer Docking Seal

    Science.gov (United States)

    Oravec, Heather Ann; Daniels, Christopher C.

    2014-01-01

    The National Aeronautics and Space Administration has been developing a novel docking system to meet the requirements of future exploration missions to low-Earth orbit and beyond. A dynamic gas pressure seal is located at the main interface between the active and passive mating components of the new docking system. This seal is designed to operate in the harsh space environment, but is also to perform within strict loading requirements while maintaining an acceptable level of leak rate. In this study, a candidate silicone elastomer seal was designed, and multiple subscale test articles were manufactured for evaluation purposes. The force required to fully compress each test article at room temperature was quantified and found to be below the maximum allowable load for the docking system. However, a significant amount of scatter was observed in the test results. Due to the stochastic nature of the mechanical performance of this candidate docking seal, a statistical process control technique was implemented to isolate unusual compression behavior from typical mechanical performance. The results of this statistical analysis indicated a lack of process control, suggesting a variation in the manufacturing phase of the process. Further investigation revealed that changes in the manufacturing molding process had occurred which may have influenced the mechanical performance of the seal. This knowledge improves the chance of this and future space seals to satisfy or exceed design specifications.

  11. Development and Control of the Naval Postgraduate School Planar Autonomous Docking Simulator (NPADS)

    Science.gov (United States)

    Porter, Robert D.

    2002-09-01

    The objective of this thesis was to design, construct and develop the initial autonomous control algorithm for the NPS Planar Autonomous Docking Simulator (NPADS) The effort included hardware design, fabrication, installation and integration; mass property determination; and the development and testing of control laws utilizing MATLAB and Simulink for modeling and LabView for NPADS control, The NPADS vehicle uses air pads and a granite table to simulate a 2-D, drag-free, zero-g space environment, It is a completely self-contained vehicle equipped with eight cold-gas, bang-bang type thrusters and a reaction wheel for motion control, A 'star sensor' CCD camera locates the vehicle on the table while a color CCD docking camera and two robotic arms will locate and dock with a target vehicle, The on-board computer system leverages PXI technology and a single source, simplifying systems integration, The vehicle is powered by two lead-acid batteries for completely autonomous operation, A graphical user interface and wireless Ethernet enable the user to command and monitor the vehicle from a remote command and data acquisition computer. Two control algorithms were developed and allow the user to either control the thrusters and reaction wheel manually or simply specify a desired location and rotation angle,

  12. Munc13-4 Is a Rab11-binding Protein That Regulates Rab11-positive Vesicle Trafficking and Docking at the Plasma Membrane.

    Science.gov (United States)

    Johnson, Jennifer L; He, Jing; Ramadass, Mahalakshmi; Pestonjamasp, Kersi; Kiosses, William B; Zhang, Jinzhong; Catz, Sergio D

    2016-02-12

    The small GTPase Rab11 and its effectors control trafficking of recycling endosomes, receptor replenishment and the up-regulation of adhesion and adaptor molecules at the plasma membrane. Despite recent advances in the understanding of Rab11-regulated mechanisms, the final steps mediating docking and fusion of Rab11-positive vesicles at the plasma membrane are not fully understood. Munc13-4 is a docking factor proposed to regulate fusion through interactions with SNAREs. In hematopoietic cells, including neutrophils, Munc13-4 regulates exocytosis in a Rab27a-dependent manner, but its possible regulation of other GTPases has not been explored in detail. Here, we show that Munc13-4 binds to Rab11 and regulates the trafficking of Rab11-containing vesicles. Using a novel Time-resolved Fluorescence Resonance Energy Transfer (TR-FRET) assay, we demonstrate that Munc13-4 binds to Rab11a but not to dominant negative Rab11a. Immunoprecipitation analysis confirmed the specificity of the interaction between Munc13-4 and Rab11, and super-resolution microscopy studies support the interaction of endogenous Munc13-4 with Rab11 at the single molecule level in neutrophils. Vesicular dynamic analysis shows the common spatio-temporal distribution of Munc13-4 and Rab11, while expression of a calcium binding-deficient mutant of Munc13-4 significantly affected Rab11 trafficking. Munc13-4-deficient neutrophils showed normal endocytosis, but the trafficking, up-regulation, and retention of Rab11-positive vesicles at the plasma membrane was significantly impaired. This correlated with deficient NADPH oxidase activation at the plasma membrane in response to Rab11 interference. Our data demonstrate that Munc13-4 is a Rab11-binding partner that regulates the final steps of Rab11-positive vesicle docking at the plasma membrane. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Microcirculation within Grooved Substrates regulates Cell Positioning and Cell Docking inside Microfluidic Channels

    Science.gov (United States)

    Manbachi, Amir; Shrivastava, Shamit; Cioffi, Margherita; Chung, Bong Geun; Moretti, Matteo; Demirci, Utkan; Yliperttula, Marjo; Khademhosseini, Ali

    2009-01-01

    Immobilization of cells inside microfluidic devices is a promising approach for enabling studies related to drug screening and cell biology. Despite extensive studies in using grooved substrates for immobilizing cells inside channels, a systematic study of the effects of various parameters that influence cell docking and retention within grooved substrates has not been performed. We demonstrate using computational simulations that the fluid dynamic environment within microgrooves significantly varies with groove width, generating micro-circulation areas in smaller microgrooves. Wall shear stress simulation predicted that shear stresses were in opposite direction in smaller grooves (25 and 50 μm wide) in comparison to those in wider grooves (75 and 100 μm wide). To validate the simulations, cells were seeded within microfluidic devices, where microgrooves of different widths were aligned perpendicularly to the direction of the flow. Experimental results showed that, as predicted, the inversion of the local direction of shear stress within the smaller grooves resulted in alignment of cells on two opposite sides of the grooves under the same flow conditions. Also, the amplitude of shear stress within microgrooved channels significantly influenced cell retainment in the channels. Therefore, our studies suggest that microscale shear stresses greatly influence cellular docking, immobilization, and retention in fluidic systems and should be considered for the design of cell-based microdevices. PMID:18432345

  14. Molecular docking.

    Science.gov (United States)

    Morris, Garrett M; Lim-Wilby, Marguerita

    2008-01-01

    Molecular docking is a key tool in structural molecular biology and computer-assisted drug design. The goal of ligand-protein docking is to predict the predominant binding mode(s) of a ligand with a protein of known three-dimensional structure. Successful docking methods search high-dimensional spaces effectively and use a scoring function that correctly ranks candidate dockings. Docking can be used to perform virtual screening on large libraries of compounds, rank the results, and propose structural hypotheses of how the ligands inhibit the target, which is invaluable in lead optimization. The setting up of the input structures for the docking is just as important as the docking itself, and analyzing the results of stochastic search methods can sometimes be unclear. This chapter discusses the background and theory of molecular docking software, and covers the usage of some of the most-cited docking software.

  15. Port positioning and docking for single-stage totally robotic dissection for rectal cancer surgery with the Si and Xi Da Vinci Surgical System.

    Science.gov (United States)

    Toh, James Wei Tatt; Kim, Seon-Hahn

    2017-11-04

    We have previously reported our technique of single-docking totally robotic dissection for rectal cancer surgery using the Da Vinci ® Si Surgical System in 2009. However, we have since optimised our port placement for the Si system and have developed a novel configuration of port placement and docking for the Da Vinci ® Xi Surgical System. We have performed over 700 cases using this technique with the Si system and have used our Xi technique since 2016 for totally robotic dissection for rectal cancer. We have kept the configuration of port placements for both the Xi and Si system as similar as possible, with the priorities to avoid arm collisions as well as to provide a workable port configuration of two left-handed instruments and one right-handed instrument. To date, there have had no major complications or arm collisions related to this technique of docking, port positioning and instrument placement.

  16. Multi-Axis Independent Electromechanical Load Control for Docking System Actuation Development and Verification Using dSPACE

    Science.gov (United States)

    Oesch, Christopher; Dick, Brandon; Rupp, Timothy

    2015-01-01

    The development of highly complex and advanced actuation systems to meet customer demands has accelerated as the use of real-time testing technology expands into multiple markets at Moog. Systems developed for the autonomous docking of human rated spacecraft to the International Space Station (ISS), envelope multi-operational characteristics which place unique constraints on an actuation system. Real-time testing hardware has been used as a platform for incremental testing and development for the linear actuation system which controls initial capture and docking for vehicles visiting the ISS. This presentation will outline the role of dSPACE hardware as a platform for rapid control-algorithm prototyping as well as an Electromechanical Actuator (EMA) system dynamic loading simulator, both conducted at Moog to develop the safety critical Linear Actuator System (LAS) of the NASA Docking System (NDS).

  17. Control rod position detection device

    International Nuclear Information System (INIS)

    Akita, Haruo; Ogiwara, Sakae.

    1996-01-01

    The device of the present invention is used in a back-up shut down system of an LMFBR type reactor which is easy for maintenance, has high reliability and can recognize the position of control rods accurately. Namely, a permanent magnet is disposed to a control rod extension tube connected to the lower portion of the control rod. The detector guide tube is disposed in the vicinity of the control rod extension tube. A detector having a detection coil is inserted into a detector tube. With such constitution, the control rod can be detected at one position using the following method. (1) the movement of the magnetic field of the permanent magnet is detected by the detection coil. (2) a plurality of grooves are formed on the control rod extension tube, and the movement of the grooves is detected. In addition, the detection coil is inserted into the detector guide tube, and the signals from the detection coil are inputted to a signal processing circuit disposed at the outside of the reactor vessel using an MI cable to enable the maintenance of the detector. Further, if the detector comprises a detection coil and an excitation coil, the position of a dropped control rod can be recognized at a plurality of points. (I.S.)

  18. Exact docking flight controller for autonomous aerial refueling with back-stepping based high order sliding mode

    Science.gov (United States)

    Su, Zikang; Wang, Honglun; Li, Na; Yu, Yue; Wu, Jianfa

    2018-02-01

    Autonomous aerial refueling (AAR) exact docking control has always been an intractable problem due to the strong nonlinearity, the tight coupling of the 6 DOF aircraft model and the complex disturbances of the multiple environment flows. In this paper, the strongly coupled nonlinear 6 DOF model of the receiver aircraft which considers the multiple flow disturbances is established in the affine nonlinear form to facilitate the nonlinear controller design. The items reflecting the influence of the unknown flow disturbances in the receiver dynamics are taken as the components of the "lumped disturbances" together with the items which have no linear correlation with the virtual control variables. These unmeasurable lumped disturbances are estimated and compensated by a specially designed high order sliding mode observer (HOSMO) with excellent estimation property. With the compensation of the estimated lumped disturbances, a back-stepping high order sliding mode based exact docking flight controller is proposed for AAR in the presence of multiple flow disturbances. Extensive simulation results demonstrate the feasibility and superiority of the proposed docking controller.

  19. UDP-N-Acetyl glucosamine pyrophosphorylase as novel target for controlling Aedes aegypti – molecular modeling, docking and simulation studies

    Directory of Open Access Journals (Sweden)

    Bhagath Kumar Palaka

    2014-12-01

    Full Text Available Aedes aegypti is a vector that transmits diseases like dengue fever, chikungunya, and yellow fever. It is distributed in all tropical and subtropical regions of the world. According to WHO reports, 40% of the world’s population is currently at risk for dengue fever. As vaccines are not available for such diseases, controlling mosquito population becomes necessary. Hence, this study aims at UDP-N-acetyl glucosamine pyrophosphorylase of Aedes aegypti (AaUAP, an essential enzyme for chitin metabolim in insects, as a drug target. Structure of AaUAP was predicted and validated using in-silico approach. Further, docking studies were performed using a set of 10 inhibitors out of which NAG9 was found to have good docking score, which was further supported by simulation studies. Hence, we propose that NAG9 can be considered as a potential hit in designing new inhibitors to control Aedes aegypti.

  20. Position control device for a control rod

    International Nuclear Information System (INIS)

    Ono, Takehiko; Kusaka, Shuji.

    1976-01-01

    Purpose: To reliably prevent dangerous operation in the control of the position of the control rod by checking for abnormal pulse motor coil excitation voltage and, at the time of occurrence of abnormality, immediately holding the control rod stationary lest it should be moved to an unsafe position, this being accomplished excitation from a compensating excitation system. Constitution: In an FBR reactor, a circuit for memorizing the correct output states of individual drive signals at arbitrary instants and consequtively producing the memorized results is provided, and the output of the circuit and the actual drive signal are compared at all times to discriminate whether the drive signal being compared is normal or not. When the actual drive signal is abnormal, a series signal varying after a predetermined pattern is shifted to enable replacement of the actual drive signal, so that irrespective of whether the problem drive signal is ''on'' or ''off'', a drive signal of the correct pattern may be supplied to the pulse motor to hold the control rod and prevent it from being moved toward the dangerous side due to its own weight or other causes. (Horiuchi, T.)

  1. The focal adhesion-associated proteins DOCK5 and GIT2 comprise a rheostat in control of epithelial invasion

    DEFF Research Database (Denmark)

    Frank, Scott R; Köllmann, C P; van Lidth de Jeude, J F

    2017-01-01

    DOCK proteins are guanine nucleotide exchange factors for Rac and Cdc42 GTPases. DOCK1 is the founding member of the family and acts downstream of integrins via the canonical Crk-p130Cas complex to activate Rac GTPases in numerous contexts. In contrast, DOCK5, which possesses the greatest similar......:10.1038/onc.2016.345....

  2. Docking Offset Between the Space Shuttle and the International Space Station and Resulting Impacts to the Transfer of Attitude Reference and Control

    Science.gov (United States)

    Helms, W. Jason; Pohlkamp, Kara M.

    2011-01-01

    The Space Shuttle does not dock at an exact 90 degrees to the International Space Station (ISS) x-body axis. This offset from 90 degrees, along with error sources within their respective attitude knowledge, causes the two vehicles to never completely agree on their attitude, even though they operate as a single, mated stack while docked. The docking offset can be measured in flight when both vehicles have good attitude reference and is a critical component in calculations to transfer attitude reference from one vehicle to another. This paper will describe how the docking offset and attitude reference errors between both vehicles are measured and how this information would be used to recover Shuttle attitude reference from ISS in the event of multiple failures. During STS-117, ISS on-board Guidance, Navigation and Control (GNC) computers began having problems and after several continuous restarts, the systems failed. The failure took the ability for ISS to maintain attitude knowledge. This paper will also demonstrate how with knowledge of the docking offset, the contingency procedure to recover Shuttle attitude reference from ISS was reversed in order to provide ISS an attitude reference from Shuttle. Finally, this paper will show how knowledge of the docking offset can be used to speed up attitude control handovers from Shuttle to ISS momentum management. By taking into account the docking offset, Shuttle can be commanded to hold a more precise attitude which better agrees with the ISS commanded attitude such that start up transients with the ISS momentum management controllers are reduced. By reducing start-up transients, attitude control can be transferred from Shuttle to ISS without the use of ISS thrusters saving precious on-board propellant, crew time and minimizing loads placed upon the mated stack.

  3. Spacecraft rendezvous and docking

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1999-01-01

    The phenomenons and problems encountered when a rendezvous manoeuvre, and possible docking, of two spacecrafts has to be performed, have been the topic for numerous studies, and, details of a variety of scenarios has been analysed. So far, all solutions that has been brought into realization has...... been based entirely on direct human supervision and control. This paper describes a vision-based system and methodology, that autonomously generates accurate guidance information that may assist a human operator in performing the tasks associated with both the rendezvous and docking navigation...

  4. Optogenetic control of organelle transport and positioning

    NARCIS (Netherlands)

    van Bergeijk, Petra; Adrian, Max; Hoogenraad, Casper C; Kapitein, Lukas C

    2015-01-01

    Proper positioning of organelles by cytoskeleton-based motor proteins underlies cellular events such as signalling, polarization and growth. For many organelles, however, the precise connection between position and function has remained unclear, because strategies to control intracellular organelle

  5. Control rod position detector for nuclear reactor

    International Nuclear Information System (INIS)

    Kudo, Mitsuru; Fujiwara, Hiroshi.

    1981-01-01

    Purpose: To improve the reliability of a control rod position detector by detecting a reactive code with a combination of control rod position change signals produced from vertical and horizontal axis decoders, generation an error signal and thus simultaneously detecting the operation of more than two lead switches. Constitution: Horizontal and vertical axis position signals responsive to changes in the control rod position are applied from lead switches connected in a predetermined matrix connection corresponding to the notches of the positions of respective position detecting probes, the reactive output from the decoder is detected by a reactive code detecting circuit, which in turn generates a fault signal, and the control rod position code converted in a notch number generating circuit is converted to a predetermined value indicating invalidity. Accordingly, a fault caused by the simultaneous operation of a plurality of failed lead switches can be effectively detected. (Yoshino, Y.)

  6. Plasma position and shape control for ITER

    International Nuclear Information System (INIS)

    Portone, A.; Gribov, Y.; Huguet, M.

    1995-01-01

    Key features and main results about the control of the plasma shape in ITER are presented. A control algorithm is designed to control up to 6 gaps between the plasma separatrix and the plasma facing components during the reference burn phase. Nonlinear simulations show the performances of the controller in the presence of plasma vertical position offsets, beta drops and power supply voltage saturation

  7. Orion Handling Qualities During ISS Rendezvous and Docking

    Science.gov (United States)

    Hart, Jeremy J.; Stephens, J. P.; Spehar, P.; Bilimoria, K.; Foster, C.; Gonzalex, R.; Sullivan, K.; Jackson, B.; Brazzel, J.; Hart, J.

    2011-01-01

    The Orion spacecraft was designed to rendezvous with multiple vehicles in low earth orbit (LEO) and beyond. To perform the required rendezvous and docking task, Orion must provide enough control authority to perform coarse translational maneuvers while maintaining precision to perform the delicate docking corrections. While Orion has autonomous docking capabilities, it is expected that final approach and docking operations with the International Space Station (ISS) will initially be performed in a manual mode. A series of evaluations was conducted by NASA and Lockheed Martin at the Johnson Space Center to determine the handling qualities (HQ) of the Orion spacecraft during different docking and rendezvous conditions using the Cooper-Harper scale. This paper will address the specifics of the handling qualities methodology, vehicle configuration, scenarios flown, data collection tools, and subject ratings and comments. The initial Orion HQ assessment examined Orion docking to the ISS. This scenario demonstrates the Translational Hand Controller (THC) handling qualities of Orion. During this initial assessment, two different scenarios were evaluated. The first was a nominal docking approach to a stable ISS, with Orion initializing with relative position dispersions and a closing rate of approximately 0.1 ft/sec. The second docking scenario was identical to the first, except the attitude motion of the ISS was modeled to simulate a stress case ( 1 degree deadband per axis and 0.01 deg/sec rate deadband per axis). For both scenarios, subjects started each run on final approach at a docking port-to-port range of 20 ft. Subjects used the THC in pulse mode with cues from the docking camera image, window views, and range and range rate data displayed on the Orion display units. As in the actual design, the attitude of the Orion vehicle was held by the automated flight control system at 0.5 degree deadband per axis. Several error sources were modeled including Reaction

  8. Plasma position control on Alcator C

    International Nuclear Information System (INIS)

    Pribyl, P.A.

    1981-05-01

    The Alcator C MHD equilibrium is investigated from the standpoint of determining the plasma position. A review of equilibrium theory is presented, indicating that the central flux surfaces of the plasma should be displaced about 1 to 2 cm from the outermost. Further, the plasma should have a slightly noncircular cross-section. A comparison is made between the observed and predicted profiles. Flux loops sensitive to plasma position generate the error signal for the feedback control circuit. This measurement agrees with other position-sensitive diagnostics, such as limiter heating, and centroids of density, soft x-ray, and electron cyclotron emission. A linear model is developed for the position control feedback system, including the vertical field SCR supply, plasma, and feedback electronics. Operation of the control system agrees well with that predicted by the model, with acceptable plasma position being maintained for the duration of the discharge. The feedback control system is in daily use for Alcator C runs

  9. Autonomous spacecraft rendezvous and docking

    Science.gov (United States)

    Tietz, J. C.; Almand, B. J.

    A storyboard display is presented which summarizes work done recently in design and simulation of autonomous video rendezvous and docking systems for spacecraft. This display includes: photographs of the simulation hardware, plots of chase vehicle trajectories from simulations, pictures of the docking aid including image processing interpretations, and drawings of the control system strategy. Viewgraph-style sheets on the display bulletin board summarize the simulation objectives, benefits, special considerations, approach, and results.

  10. Positive Exchange of Flight Controls Program

    Science.gov (United States)

    1995-03-10

    This advisory circular provides guidance for all pilots, especially student pilots, flight instructors, and pilot examiners, on the recommended procedure to use for the positive exchange of flight controls between pilots when operating an aircraft.

  11. Plasma position control in TCABR Tokamak

    International Nuclear Information System (INIS)

    Galvao, R.M.O.; Kuznetsov, Yu. K.; Nascimento, I.C.; Fonseca, A.M.M.; Silva, R.P. da; Ruchko, L.F.; Tuszel, A.G.; Reis, A.P. dos; Sanada, E.K.

    1998-01-01

    The plasma control position in the TCABR tokamak is described. The TCA tokamak was transferred from the Centre de Recherches en Physique des Plasmas, Lausanne, to the Institute of Physics of University of Sao Paulo, renamed TCABR (α=0.18 m, R = 0.62 m, B = 1 T,I p = 100 kA). The control system was reconstructed using mainly components obtained from the TCA tokamak. A new method of plasma position determination is used in TCABR to improve its accuracy. A more detailed theoretical analysis of the feed forward and feedback control is performed as compared with. (author)

  12. Development and Control of the Naval Postgraduate School Planar Autonomous Docking Simulator (NPADS)

    National Research Council Canada - National Science Library

    Porter, Robert

    2002-01-01

    ...; and the development and testing of control laws utilizing MATLAB and Simulink for modeling and LabView for NPADS control, The NPADS vehicle uses air pads and a granite table to simulate a 2-D, drag...

  13. Plasma position control device for thermonuclear device

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, Masanori [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Fujita, Jun-ya; Ioki, Kimihiro

    1995-10-03

    The present invention concerns plasma position control coils having a feeder line structure not requiring high strength for the support portion. Namely, the coils are formed by twisting feeder lines extended from plasma position control coils in a vacuum vessel. The twisted feeder lines are supported using an appropriate structural member. Electromagnetic load is generated to the feeder lines being extended from the position control coils and traversing toroidal fields at a current introduction lines and at current delivery lines respectively. However, since the feeder lines have substantially spiral shape consisting of two twisted lines, the electromagnetic load and the moment caused by the generated load which are inversed to each other are off set. Accordingly, only extremely small force is exerted on the fittings which support the feeder lines. Therefore, small strength may suffice for the fittings and the gaps of mounting the fittings may be made longer. (I.S.).

  14. Plasma position control device for thermonuclear device

    International Nuclear Information System (INIS)

    Onozuka, Masanori; Fujita, Jun-ya; Ioki, Kimihiro.

    1995-01-01

    The present invention concerns plasma position control coils having a feeder line structure not requiring high strength for the support portion. Namely, the coils are formed by twisting feeder lines extended from plasma position control coils in a vacuum vessel. The twisted feeder lines are supported using an appropriate structural member. Electromagnetic load is generated to the feeder lines being extended from the position control coils and traversing toroidal fields at a current introduction lines and at current delivery lines respectively. However, since the feeder lines have substantially spiral shape consisting of two twisted lines, the electromagnetic load and the moment caused by the generated load which are inversed to each other are off set. Accordingly, only extremely small force is exerted on the fittings which support the feeder lines. Therefore, small strength may suffice for the fittings and the gaps of mounting the fittings may be made longer. (I.S.)

  15. Validation of ISTTOK Plasma Position Controller

    International Nuclear Information System (INIS)

    Valcarcel, D. F.; Carvalho, I. S.; Carvalho, B. B.; Fernandes, H.; Silva, C.; Duarte, P.; Duarte, A.; Carvalho, P. J.; Pereira, T.

    2008-01-01

    Active control of plasma position on the ISTTOK tokamak is of extreme importance due to the inherent instability caused by an unfavourable curvature of the external equilibrium magnetic field. The consequences of this instability can be suppressed by applying a dynamic equilibrium field. A digital real-time plasma position control system for ISTTOK has been developed to perform this task. This system uses magnetic measurements to determine the plasma position and feeds the control signal to power supplies that generate the equilibrium fields. After commissioning, the results obtained have shown some discrepancies between the magnetic plasma position reconstruction and several other diagnostics, such as tomography. This discrepancy at some extent is due to the effect of the external magnetic fields on the poloidal magnetic measurements. This work presents a study that addresses this issue. In a future work it will lead to the development of a corrected plasma position algorithm, aiming at obtaining improved performance of plasma discharges and controlled plasma column displacements

  16. Impulse position control algorithms for nonlinear systems

    Energy Technology Data Exchange (ETDEWEB)

    Sesekin, A. N., E-mail: sesekin@list.ru [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002 (Russian Federation); Institute of Mathematics and Mechanics, Ural Division of Russian Academy of Sciences, 16 S. Kovalevskaya, Ekaterinburg, 620990 (Russian Federation); Nepp, A. N., E-mail: anepp@urfu.ru [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002 (Russian Federation)

    2015-11-30

    The article is devoted to the formalization and description of impulse-sliding regime in nonlinear dynamical systems that arise in the application of impulse position controls of a special kind. The concept of trajectory impulse-sliding regime formalized as some limiting network element Euler polygons generated by a discrete approximation of the impulse position control This paper differs from the previously published papers in that it uses a definition of solutions of systems with impulse controls, it based on the closure of the set of smooth solutions in the space of functions of bounded variation. The need for the study of such regimes is the fact that they often arise when parry disturbances acting on technical or economic control system.

  17. Impulse position control algorithms for nonlinear systems

    Science.gov (United States)

    Sesekin, A. N.; Nepp, A. N.

    2015-11-01

    The article is devoted to the formalization and description of impulse-sliding regime in nonlinear dynamical systems that arise in the application of impulse position controls of a special kind. The concept of trajectory impulse-sliding regime formalized as some limiting network element Euler polygons generated by a discrete approximation of the impulse position control This paper differs from the previously published papers in that it uses a definition of solutions of systems with impulse controls, it based on the closure of the set of smooth solutions in the space of functions of bounded variation. The need for the study of such regimes is the fact that they often arise when parry disturbances acting on technical or economic control system.

  18. Remote docking apparatus

    International Nuclear Information System (INIS)

    Dent, T.H.; Sumpman, W.C.; Wilhelm, J.J.

    1981-01-01

    The remote docking apparatus comprises a support plate with locking devices mounted thereon. The locking devices are capable of being inserted into tubular members for suspending the support plate therefrom. A vertical member is attached to the support plate with an attachment mechanism attached to the vertical member. A remote access manipulator is capable of being attached to the attachment mechanism so that the vertical member can position the remote access manipulator so that the remote access manipulator can be initially attached to the tubular members in a well defined manner

  19. Automatic positioning control device for automatic control rod exchanger

    International Nuclear Information System (INIS)

    Nasu, Seiji; Sasaki, Masayoshi.

    1982-01-01

    Purpose: To attain accurate positioning for a control rod exchanger. Constitution: The present position for an automatic control rod exchanger is detected by a synchro generator. An aimed stopping position for the exchanger, a stop instruction range depending on the distantial operation delay in the control system and the inertia-running distance of the mechanical system, and a coincidence confirmation range depending on the required positioning accuracy are previously set. If there is a difference between the present position and the aimed stopping position, the automatic exchanger is caused to run toward the aimed stopping position. A stop instruction is generated upon arrival at the position within said stop instruction range, and a coincidence confirmation signal is generated upon arrival at the position within the coincidence confirmation range. Since uncertain factors such as operation delay in the control system and the inertia-running distance of the mechanical system that influence the positioning accuracy are made definite by the method of actual measurement or the like and the stop instruction range and the coincidence confirmation range are set based on the measured data, the accuracy for the positioning can be improved. (Ikeda, J.)

  20. Upper limb position control in fibromyalgia

    Directory of Open Access Journals (Sweden)

    Bardal Ellen

    2012-09-01

    Full Text Available Abstract Background Motor problems are reported by patients with fibromyalgia (FM. However, the mechanisms leading to alterations in motor performance are not well understood. In this study, upper limb position control during sustained isometric contractions was investigated in patients with FM and in healthy controls (HCs. Methods Fifteen female FM patients and 13 HCs were asked to keep a constant upper limb position during sustained elbow flexion and shoulder abduction, respectively. Subjects received real-time visual feedback on limb position and both tasks were performed unloaded and while supporting loads (1, 2, and 3 kg. Accelerations of the dominant upper limb were recorded, with variance (SD of mean position and power spectrum analysis used to characterize limb position control. Normalized power of the acceleration signal was extracted for three frequency bands: 1–3 Hz, 4–7 Hz, and 8–12 Hz. Results Variance increased with load in both tasks (P 0.001 but did not differ significantly between patients and HCs (P > 0.17. Power spectrum analysis showed that the FM patients had a higher proportion of normalized power in the 1–3 Hz band, and a lower proportion of normalized power in the 8–12 Hz band compared to HCs (P 0.05. The results were consistent for all load conditions and for both elbow flexion and shoulder abduction. Conclusion FM patients exhibit an altered neuromuscular strategy for upper limb position control compared to HCs. The predominance of low-frequency limb oscillations among FM patients may indicate a sensory deficit.

  1. Variable pattern contamination control under positive pressure

    International Nuclear Information System (INIS)

    Philippi, H.M.

    1997-01-01

    Airborne contamination control in nuclear and biological laboratories is traditionally achieved by directing the space ventilation air at subatmospheric pressures in one fixed flow pattern. However, biological and nuclear contamination flow control in the new Biological Research Facility, to be commissioned at the Chalk River Laboratories in 1996, will have the flexibility to institute a number of contamination control patterns, all achieved at positive (above atmospheric) pressures. This flexibility feature, made possible by means of a digitally controlled ventilation system, changes the facility ventilation system from being a relatively rigid building service operated by plant personnel into a flexible building service which can be operated by the facility research personnel. This paper focuses on and describes the application of these unique contamination control features in the design of the new Biological Research Facility. 3 refs., 7 figs

  2. Variable pattern contamination control under positive pressure

    Energy Technology Data Exchange (ETDEWEB)

    Philippi, H.M. [Chalk River Labs., Ontario (Canada)

    1997-08-01

    Airborne contamination control in nuclear and biological laboratories is traditionally achieved by directing the space ventilation air at subatmospheric pressures in one fixed flow pattern. However, biological and nuclear contamination flow control in the new Biological Research Facility, to be commissioned at the Chalk River Laboratories in 1996, will have the flexibility to institute a number of contamination control patterns, all achieved at positive (above atmospheric) pressures. This flexibility feature, made possible by means of a digitally controlled ventilation system, changes the facility ventilation system from being a relatively rigid building service operated by plant personnel into a flexible building service which can be operated by the facility research personnel. This paper focuses on and describes the application of these unique contamination control features in the design of the new Biological Research Facility. 3 refs., 7 figs.

  3. Chemical Control of Curled Dock (Rumex crispus L. and Other Weeds in Noncropped Areas

    Directory of Open Access Journals (Sweden)

    Tsvetanka Dimitrova

    2008-01-01

    Full Text Available Rumex crispus L. is an invasive species widespread in our country and in particular in the region of North Bulgaria. It is characterized by high biological and ecological plasticity. Owing to its great reproductive potential, the weed has been assigned to the list of economically most important weeds in the country. With the purpose of studying the possibility of chemical weed control in noncropped areas with heavy natural background infestation with R. crispus L. and other dicotyledonous weeds, two field trials were carried out. A ready-to-use herbicide mixture 2,4-D 140.2 g/l-1 + Triclopyr 144 g/l-1, trade product Genoxon 3X (X0050, was tested at two doses of active ingredient, 3552 and 2842 ml/ha-1. It was found that: (1 population density of Rumex crispus L. can be successfully reduced by treatment at the stage of early stem formation; herbicideefficacy with 3552 and 2882 ml/ha-1 doses on the 21st day after treatment was 100% and 90.5%, respectively, at the end of vegetation 94.4 and 85.7%, respectively; (2 herbicidal efficacy was lower when R. crispus L. was treated at the 5 - 6 leaf stage, being 100 – 94.1%and 80 – 76.5% respectively for the indicated doses and time of recording; (3 at the studied doses the herbicide controlled both annual dicotyledonous weeds (Amaranthus spp., Chenopodium album L., Portulaca oleracea L. and perennial dicotyledonous ones (Cirsiumarvense L., Sonchus arvensis L., Convolvulus arvensis L., Carduus acanthoides L., but it was not toxic to monocotyledonous weeds.

  4. RODMOD: a code for control rod positioning

    International Nuclear Information System (INIS)

    Vondy, D.R.; Fowler, T.B.

    1978-11-01

    The report documents a computer code which has been implemented to position control rods according to a prescribed schedule during the calculation of a reactor history. Control rods may be represented explicitly with or without internal black absorber conditions in selected energy groups, or fractional insertion may be done, or both, in a problem. There is provision for control rod follower, movement of materials through a series of zones in a closed loop, and shutdown rod insertion and subsequent removal to allow the reactor history calculation to be continued. This code is incorporated in the system containing the VENTURE diffusion theory neutronics and the BURNER exposure codes for routine use. The implemented automated procedures cause the prescribed control rod insertion schedule to be applied without the access of additional user input data during the calculation of a reactor operating history

  5. CT-docking patient stretcher

    International Nuclear Information System (INIS)

    Mirvis, S.E.; Owens, E.; Maslyn, J.; Rizutto, M.

    1990-01-01

    This paper assesses the use of a patient stretcher that directly docks to a CT scanner for acutely injured and/or critically ill patients. The stretcher permits performance of radiography and acts as a platform for critical care monitoring and patient support devices. During a 1-year period, the prototype CT-docking stretcher was used for 35 patients sustaining acute trauma and 25 patients from critical care units. Observations were elicited from physicians, nurses and technologists concerning the advantages or disadvantages of the docking stretcher. Advantages of the CT-docking stretcher included time saved in moving patients to the CT table from the admitting/emergency ward, transfer of critically ill patients onto the stretcher in the controlled environment of the intensive care unit rather than the CT suite, increasing CT throughput by direct docking of the patient stretcher to the CT scanner rather than manual transfer of complex support and monitoring devices with the patient, decreased risk associated with physical movement of patients with potentially unstable spinal injuries or unstable physiologic status, and decrease in potential for injury to medical personnel performing patient transfer

  6. Robust hydraulic position controller by a fuzzy state controller

    International Nuclear Information System (INIS)

    Zhao, T.; Van der Wal, A.J.

    1994-01-01

    In nuclear industry, one of the most important design considerations of controllers is their robustness. Robustness in this context is defined as the ability of a system to be controlled in a stable way over a wide range of system parameters. Generally the systems to be controlled are linearized, and stability is subsequently proven for this idealized system. By combining classical control theory and fuzzy set theory, a new kind of state controller is proposed and successfully applied to a hydraulic position servo with excellent robustness against variation of system parameters

  7. Angular Position Tracking Control of a Quadcopter

    Directory of Open Access Journals (Sweden)

    T. V. Glazkov

    2017-01-01

    Full Text Available The paper dwells on tracking the quad-copter angular position with desired quality parameters of transient processes. The aerial vehicle is considered as a rigid body with six degrees of freedom.  A full rigid body quad-copter mathematical model is considered without the assumption of smallness of the Euler angles.Among the most well known methods of non-linear stabilization are feedback linearization and backstepping. The backstepping approach allows us to have an effective solution of the stabilization problems with uncertainties available in the system. However, in synthesis of the feedback through backstepping, there is still an urgent issue: how to ensure desirable quality of transients in the closed-loop system. The paper presents a solution of this problem using as an example the tracking a given (programmed change of the angular position of a quad-copter.The control algorithms obtained in this paper are implemented using the Rolling Spider MATLAB Toolbox (ROSMAT tool package on the Parrot Rolling Spider quad-copter. A numerical simulation and experiments have shown the efficiency of obtained control laws, with the transient processes taking into account the desired quality indicators. However, the experiments showed that lack of terms in the mathematical model to describe the aerodynamic effects, resulted in the instability of the quad-copter flight near the obstacle (the effect of the reflected airflow.Further research can be aimed at solving the control problem in question using a mathematical model of the quad-copter motion that takes into account various aerodynamic effects.One of the potential application areas for the theoretical results, obtained in the paper, is to solve the problems of automatic control of unmanned aerial vehicles.

  8. Active vibration control of clamped beams using positive position feedback controllers with moment pair

    International Nuclear Information System (INIS)

    Shin, Chang Joo; Jeong, Weui Bong; Hong, Chin Suk

    2012-01-01

    This paper investigates the active vibration control of clamp beams using positive position feedback (PPF) controllers with a sensor/ moment pair actuator. The sensor/moment pair actuator which is the non-collocated configuration leads to instability of the control system when using the direct velocity feedback (DVFB) control. To alleviate the instability problem, a PPF controller is considered in this paper. A parametric study of the control system with PPF controller is first conducted to characterize the effects of the design parameters (gain and damping ratio in this paper) on the stability and performance. The gain of the controller is found to affect only the relative stability. Increasing the damping ratio of the controller slightly improves the stability condition while the performance gets worse. In addition, the higher mode tuned PPF controller affects the system response at the lower modes significantly. Based on the characteristics of PPF controllers, a multi-mode controllable SISO PPF controller is then considered and tuned to different modes (in this case, three lowest modes) numerically and experimentally. The multi-mode PPF controller can be achieved to have a high gain margin. Moreover, it reduces the vibration of the beam significantly. The vibration levels at the tuned modes are reduced by about 11 dB

  9. Boundary mediated position control of traveling waves

    Science.gov (United States)

    Martens, Steffen; Ziepke, Alexander; Engel, Harald

    Reaction control is an essential task in biological systems and chemical process industry. Often, the excitable medium supporting wave propagation exhibits an irregular shape and/or is limited in size. In particular, the analytic treatment of wave phenomena is notoriously difficult due to the spatial modulation of the domain's. Recently, we have provided a first systematic treatment by applying asymptotic perturbation analysis leading to an approximate description that involves a reduction of dimensionality; the 3D RD equation with spatially dependent NFBCs on the reactants reduces to a 1D reaction-diffusion-advection equation. Here, we present a novel method to control the position ϕ (t) of traveling waves in modulated domains according to a prespecified protocol of motion. Given this protocol, the ``optimal'' geometry of reactive domains Q (x) is found as the solution of the perturbatively derived equation of motion. Noteworthy, such a boundary control can be expressed in terms of the uncontrolled wave profile and its propagation velocity, rendering detailed knowledge of the reaction kinetics unnecessary. German Science Foundation DFG through the SFB 910 ''Control of Self-Organizing Nonlinear Systems''.

  10. Robust position control of induction motor using fuzzy logic control

    International Nuclear Information System (INIS)

    Kim, Sei Chan; Kim, Duk Hun; Yang, Seung Ho; Won, Chung Yuen

    1993-01-01

    In recent years, fuzzy logic or fuzzy set theory has reveived attention of a number of researchers in the area of power electronics and motion control. The paper describes a vector-controlled induction motor position servo drive where fuzzy control is used to get robustness against parameter variation and load torque disturbance effects. Both coarse and fine control with the help of look-up rule tables are used to improve transient response and system settling time. The performance characteristics are then compared with those of proportional-integral(PI) control. The simulation results clearly indicate the superiority of fuzzy control with larger number of rules. The fuzzy controller was implemented with a 16-bit microprocessor and tested in laboratory on a 3-hp IGBT inverter induction motor drive system. The test results verify the simulation performance. (Author)

  11. A Novel Docking System for Modular Self-Reconfigurable Robots

    Directory of Open Access Journals (Sweden)

    Tan Zhang

    2017-10-01

    Full Text Available Existing self-reconfigurable robots achieve connections and disconnections by a separate drive of the docking system. In this paper, we present a new docking system with which the connections and disconnections are driven by locomotion actuators, without the need for a separate drive, which reduces the weight and the complexity of the modules. This self-reconfigurable robot consists of two types of fundamental modules, i.e., active and passive modules. By the docking system, two types of connections are formed with the fundamental modules, and the docking and undocking actions are achieved through simple control with less sensory feedback. This paper describes the design of the robotic modules, the docking system, the docking process, and the docking force analysis. An experiment is performed to demonstrate the self-reconfigurable robot with the docking system.

  12. Spent fuel canister docking station

    International Nuclear Information System (INIS)

    Suikki, M.

    2006-01-01

    The working report for the spent fuel canister docking station presents a design for the operation and structure of the docking equipment located in the fuel handling cell for the spent fuel in the encapsulation plant. The report contains a description of the basic requirements for the docking station equipment and their implementation, the operation of the equipment, maintenance and a cost estimate. In the designing of the equipment all the problems related with the operation have been solved at the level of principle, nevertheless, detailed designing and the selection of final components have not yet been carried out. In case of defects and failures, solutions have been considered for postulated problems, and furthermore, the entire equipment was gone through by the means of systematic risk analysis (PFMEA). During the docking station designing we came across with needs to influence the structure of the actual disposal canister for spent nuclear fuel, too. Proposed changes for the structure of the steel lid fastening screw were included in the report. The report also contains a description of installation with the fuel handling cell structures. The purpose of the docking station for the fuel handling cell is to position and to seal the disposal canister for spent nuclear fuel into a penetration located on the cell floor and to provide suitable means for executing the loading of the disposal canister and the changing of atmosphere. The designed docking station consists of a docking ring, a covering hatch, a protective cone and an atmosphere-changing cap as well as the vacuum technology pertaining to the changing of atmosphere and the inert gas system. As far as the solutions are concerned, we have arrived at rather simple structures and most of the actuators of the system are situated outside of the actual fuel handling cell. When necessary, the equipment can also be used for the dismantling of a faulty disposal canister, cut from its upper end by machining. The

  13. Rosetta Ligand docking with flexible XML protocols.

    Science.gov (United States)

    Lemmon, Gordon; Meiler, Jens

    2012-01-01

    RosettaLigand is premiere software for predicting how a protein and a small molecule interact. Benchmark studies demonstrate that 70% of the top scoring RosettaLigand predicted interfaces are within 2Å RMSD from the crystal structure [1]. The latest release of Rosetta ligand software includes many new features, such as (1) docking of multiple ligands simultaneously, (2) representing ligands as fragments for greater flexibility, (3) redesign of the interface during docking, and (4) an XML script based interface that gives the user full control of the ligand docking protocol.

  14. Towards ligand docking including explicit interface water molecules.

    Directory of Open Access Journals (Sweden)

    Gordon Lemmon

    Full Text Available Small molecule docking predicts the interaction of a small molecule ligand with a protein at atomic-detail accuracy including position and conformation the ligand but also conformational changes of the protein upon ligand binding. While successful in the majority of cases, docking algorithms including RosettaLigand fail in some cases to predict the correct protein/ligand complex structure. In this study we show that simultaneous docking of explicit interface water molecules greatly improves Rosetta's ability to distinguish correct from incorrect ligand poses. This result holds true for both protein-centric water docking wherein waters are located relative to the protein binding site and ligand-centric water docking wherein waters move with the ligand during docking. Protein-centric docking is used to model 99 HIV-1 protease/protease inhibitor structures. We find protease inhibitor placement improving at a ratio of 9:1 when one critical interface water molecule is included in the docking simulation. Ligand-centric docking is applied to 341 structures from the CSAR benchmark of diverse protein/ligand complexes [1]. Across this diverse dataset we see up to 56% recovery of failed docking studies, when waters are included in the docking simulation.

  15. Molecular dynamics simulations and docking enable to explore the biophysical factors controlling the yields of engineered nanobodies

    Science.gov (United States)

    Soler, Miguel A.; De Marco, Ario; Fortuna, Sara

    2016-10-01

    Nanobodies (VHHs) have proved to be valuable substitutes of conventional antibodies for molecular recognition. Their small size represents a precious advantage for rational mutagenesis based on modelling. Here we address the problem of predicting how Camelidae nanobody sequences can tolerate mutations by developing a simulation protocol based on all-atom molecular dynamics and whole-molecule docking. The method was tested on two sets of nanobodies characterized experimentally for their biophysical features. One set contained point mutations introduced to humanize a wild type sequence, in the second the CDRs were swapped between single-domain frameworks with Camelidae and human hallmarks. The method resulted in accurate scoring approaches to predict experimental yields and enabled to identify the structural modifications induced by mutations. This work is a promising tool for the in silico development of single-domain antibodies and opens the opportunity to customize single functional domains of larger macromolecules.

  16. Plasma position control in SST1 tokamak

    Indian Academy of Sciences (India)

    also placed inside the vessel, however the controller would ignore fast but insignificant changes in radius arising ... poloidal cross-sectional view of the SST1 plasma along with the stabilizers are shown in figure 1 and ... [1] model which has shown excellent agreement with control experiments in TCV tokamak and also with ...

  17. Positional control of space robot manipulator

    Science.gov (United States)

    Kurochkin, Vladislav; Shymanchuk, Dzmitry

    2018-05-01

    In this article the mathematical model of a planar space robot manipulator is under study. The space robot manipulator represents a solid body with attached manipulators. The system of equations of motion is determined using the Lagrange's equations. The control problem concerning moving the robot to a given point and return it to a given trajectory in the phase space is solved. Changes of generalized coordinates and necessary control actions are plotted for a specific model.

  18. Angular Position Tracking Control of a Quadcopter

    OpenAIRE

    T. V. Glazkov; A. E. Golubev

    2017-01-01

    The paper dwells on tracking the quad-copter angular position with desired quality parameters of transient processes. The aerial vehicle is considered as a rigid body with six degrees of freedom.  A full rigid body quad-copter mathematical model is considered without the assumption of smallness of the Euler angles.Among the most well known methods of non-linear stabilization are feedback linearization and backstepping. The backstepping approach allows us to have an effective solution of the s...

  19. Fractional-Order Control of Pneumatic Position Servosystems

    Directory of Open Access Journals (Sweden)

    Cao Junyi

    2011-01-01

    Full Text Available A fractional-order control strategy for pneumatic position servosystem is presented in this paper. The idea of the fractional calculus application to control theory was introduced in many works, and its advantages were proved. However, the realization of fractional-order controllers for pneumatic position servosystems has not been investigated. Based on the relationship between the pressure in cylinder and the rate of mass flow into the cylinder, the dynamic model of pneumatic position servo system is established. The fractional-order controller for pneumatic position servo and its implementation in industrial computer is designed. The experiments with fractional-order controller are carried out under various conditions, which include sine position signal with different frequency and amplitude, step position signal, and variety inertial load. The results show the effectiveness of the proposed scheme and verify their fine control performance for pneumatic position servo system.

  20. Application of Adaptive Sliding Mode Position Controller with PI ...

    African Journals Online (AJOL)

    PISMC) techniques for controlling the rotor position of PMDC motor drive system. In particular, since SMC is robust in the presence of the matched uncertainties and external disturbances, the desired position is perfectly tracked. In addition, the ...

  1. Tool position tracking control of a nonlinear uncertain flexible robot ...

    Indian Academy of Sciences (India)

    Robot manipulators have become progressively important in the field of flexible ... this research, tracking of tool position and minimization of motor torque are ...... and Menhaj M B 2013a Position and current control of a permanent-magnet syn-.

  2. Fractional-Order Control of Pneumatic Position Servosystems

    OpenAIRE

    Junyi, Cao; Binggang, Cao

    2011-01-01

    A fractional-order control strategy for pneumatic position servosystem is presented in this paper. The idea of the fractional calculus application to control theory was introduced in many works, and its advantages were proved. However, the realization of fractional-order controllers for pneumatic position servosystems has not been investigated. Based on the relationship between the pressure in cylinder and the rate of mass flow into the cylinder, the dynamic model of pneumatic position servo ...

  3. Anti-Windup Scheme for Practical Control of Positioning Systems

    Directory of Open Access Journals (Sweden)

    Wahyudi Tarig Faisal and Abdulgani Albagul

    2012-10-01

    Full Text Available Positioning systems generally need a good controller to achieve high accuracy, fast response and robustness. In addition, ease of controller design and simplicity of controller structure are very important for practical application.  For satisfying these requirements, nominal characteristic trajectory following controller (NCTF has been proposed as a practical point-to-point (PTP positioning control. However, the effect of actuator saturation can not be completely compensated for due to the integrator windup as the plant parameters vary. This paper presents a method to improve the NCTF controller for overcoming the problem of integrator windup using simple and classical tracking anti-windup scheme. The improved NCTF controller is evaluated through simulation using a rotary positioning system. The results show that the improved NCTF controller is adequate to compensate for the effect of integrator windup. Keywords: Positioning, point-to-point, integrator windup, compensation, controller, robustness.

  4. Crusader Automated Docking System: Technology support for the Crusader Resupply Team. Interim report, Ammunition Logistics Program

    Energy Technology Data Exchange (ETDEWEB)

    Kring, C.T.; Varma, V.K.; Jatko, W.B.

    1995-11-01

    The US Army and Team Crusader (United Defense, Lockheed Martin Armament Systems, etc.) are developing the next generation howitzer, the Crusader. The development program includes an advanced, self-propelled liquid propellant howitzer and a companion resupply vehicle. The resupply vehicle is intended to rendezvous with the howitzer near the battlefront and replenish ammunition, fuel, and other material. The Army has recommended that Crusader incorporate new and innovative technologies to improve performance and safety. One conceptual design proposes a robotic resupply boom on the resupply vehicle to upload supplies to the howitzer. The resupply boom would normally be retracted inside the resupply vehicle during transit. When the two vehicles are within range of the resupply boom, the boom would be extended to a receiving port on the howitzer. In order to reduce exposure to small arms fire or nuclear, biological, and chemical hazards, the crew would remain inside the resupply vehicle during the resupply operation. The process of extending the boom and linking with the receiving port is called docking. A boom operator would be designated to maneuver the boom into contact with the receiving port using a mechanical joystick. The docking operation depends greatly upon the skill of the boom operator to manipulate the boom into docking position. Computer simulations at the National Aeronautics and Space Administration have shown that computer-assisted or autonomous docking can improve the ability of the operator to dock safely and quickly. This document describes the present status of the Crusader Autonomous Docking System (CADS) implemented at Oak Ridge National laboratory (ORNL). The purpose of the CADS project is to determine the feasibility and performance limitations of vision systems to satisfy the autonomous docking requirements for Crusader and conduct a demonstration under controlled conditions.

  5. Sensorless SPMSM Position Estimation Using Position Estimation Error Suppression Control and EKF in Wide Speed Range

    Directory of Open Access Journals (Sweden)

    Zhanshan Wang

    2014-01-01

    Full Text Available The control of a high performance alternative current (AC motor drive under sensorless operation needs the accurate estimation of rotor position. In this paper, one method of accurately estimating rotor position by using both motor complex number model based position estimation and position estimation error suppression proportion integral (PI controller is proposed for the sensorless control of the surface permanent magnet synchronous motor (SPMSM. In order to guarantee the accuracy of rotor position estimation in the flux-weakening region, one scheme of identifying the permanent magnet flux of SPMSM by extended Kalman filter (EKF is also proposed, which formed the effective combination method to realize the sensorless control of SPMSM with high accuracy. The simulation results demonstrated the validity and feasibility of the proposed position/speed estimation system.

  6. Nano positioning control for dual stage using minimum order observer

    International Nuclear Information System (INIS)

    Kim, Hong Gun

    2012-01-01

    A nano positioning control is developed using the ultra-precision positioning apparatus such as actuator, sensor, guide, power transmission element with an appropriate control method. Using established procedures, a single plane X-Y stage with ultra-precision positioning is manufactured. A global stage for materialization with robust system is combined by using an AC servo motor with a ball screw and rolling guide. An ultra-precision positioning system is developed using a micro stage with an elastic hinge and piezo element. Global and micro servos for positioning with nanometer accuracy are controlled simultaneously using an incremental encoder and a laser interferometer to measure displacement. Using established procedures, an ultra-precision positioning system (100 mm stroke and ±10 nm positioning accuracy) with a single plane X-Y stage is fabricated. Its performance is evaluated through simulation using Matlab. After analyzing previous control algorithms and adapting modern control theory, a dual servo algorithm is developed for a minimum order observer to secure the stability and priority on the controller. The simulations and experiments on the ultra precision positioning and the stability of the ultra-precision positioning system with single plane X-Y stage and the priority of the control algorithm are secured by using Matlab with Simulink and ControlDesk made in dSPACE

  7. Nano positioning control for dual stage using minimum order observer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Gun [Jeonju University, Jeonju (Korea, Republic of)

    2012-03-15

    A nano positioning control is developed using the ultra-precision positioning apparatus such as actuator, sensor, guide, power transmission element with an appropriate control method. Using established procedures, a single plane X-Y stage with ultra-precision positioning is manufactured. A global stage for materialization with robust system is combined by using an AC servo motor with a ball screw and rolling guide. An ultra-precision positioning system is developed using a micro stage with an elastic hinge and piezo element. Global and micro servos for positioning with nanometer accuracy are controlled simultaneously using an incremental encoder and a laser interferometer to measure displacement. Using established procedures, an ultra-precision positioning system (100 mm stroke and {+-}10 nm positioning accuracy) with a single plane X-Y stage is fabricated. Its performance is evaluated through simulation using Matlab. After analyzing previous control algorithms and adapting modern control theory, a dual servo algorithm is developed for a minimum order observer to secure the stability and priority on the controller. The simulations and experiments on the ultra precision positioning and the stability of the ultra-precision positioning system with single plane X-Y stage and the priority of the control algorithm are secured by using Matlab with Simulink and ControlDesk made in dSPACE.

  8. Control system design for nano-positioning using piezoelectric actuators

    International Nuclear Information System (INIS)

    Shan, Jinjun; Liu, Yanfang; Cui, Naigang; Gabbert, Ulrich

    2016-01-01

    This paper presents a systematic control system design for nano-positioning of a piezoelectric actuator (PEA). PEAs exhibit hysteresis nonlinearity, which can dramatically limit the application and performance of linear feedback control theory. Thus the hysteresis is compensated for based on the Maxwell resistive capacitor (MRC) model first. Then a proportional plus integral (PI) controller and a proportional double integral plus lead compensation (PII and L) controller are designed for the hysteresis-compensated PEA to account for model uncertainty, disturbance, and noise. The robust stability of both controllers is proved. The effectiveness of the proposed control scheme is demonstrated experimentally. Both controllers achieve fast precise positioning. The 2% settling times for the PI controller and the PII and L controller are 1.5 ms and 4.7 ms, respectively. The positioning resolution is upto 1 nm for both controllers. (paper)

  9. Modeling And Position Control Of Scara Type 3D Printer

    Directory of Open Access Journals (Sweden)

    Ahmet Saygamp305n Ogulmuamp351

    2015-08-01

    Full Text Available In this work a scara robot type 3D printer system is dynamically modeled and position control of the system is realized. For this aim computer aided design model of three degrees of freedom robotic system is created using SolidWorks program then obtained model is exported to MATLABSimMechanics software for position control. Also mathematical model of servo motors used in robotic 3D printer system is included in control methodology to design proportional controllers. Uncontrolled and controlled position results are simulated and given in the form of the graphics.

  10. An autonomous rendezvous and docking system using cruise missile technologies

    Science.gov (United States)

    Jones, Ruel Edwin

    1991-01-01

    In November 1990 the Autonomous Rendezvous & Docking (AR&D) system was first demonstrated for members of NASA's Strategic Avionics Technology Working Group. This simulation utilized prototype hardware from the Cruise Missile and Advanced Centaur Avionics systems. The object was to show that all the accuracy, reliability and operational requirements established for a space craft to dock with Space Station Freedom could be met by the proposed system. The rapid prototyping capabilities of the Advanced Avionics Systems Development Laboratory were used to evaluate the proposed system in a real time, hardware in the loop simulation of the rendezvous and docking reference mission. The simulation permits manual, supervised automatic and fully autonomous operations to be evaluated. It is also being upgraded to be able to test an Autonomous Approach and Landing (AA&L) system. The AA&L and AR&D systems are very similar. Both use inertial guidance and control systems supplemented by GPS. Both use an Image Processing System (IPS), for target recognition and tracking. The IPS includes a general purpose multiprocessor computer and a selected suite of sensors that will provide the required relative position and orientation data. Graphic displays can also be generated by the computer, providing the astronaut / operator with real-time guidance and navigation data with enhanced video or sensor imagery.

  11. Feedback control of plasma position in the HL-1 tokamak

    International Nuclear Information System (INIS)

    Yuan Baoshan; Jiao Boliang; Yang Kailing

    1991-01-01

    In the HL-1 tokamak with a thick copper shell, the control of plasma position is successfully performed by a feedback-feedforward system with dual mode regulator and the equilibrium field coils outside the shell. The plasma position can be controlled within ±2 mm in both vertical and horizontal directions under the condition that the iron core of transformer is not saturated

  12. Positive affect improves working memory: implications for controlled cognitive processing.

    Science.gov (United States)

    Yang, Hwajin; Yang, Sujin; Isen, Alice M

    2013-01-01

    This study examined the effects of positive affect on working memory (WM) and short-term memory (STM). Given that WM involves both storage and controlled processing and that STM primarily involves storage processing, we hypothesised that if positive affect facilitates controlled processing, it should improve WM more than STM. The results demonstrated that positive affect, compared with neutral affect, significantly enhanced WM, as measured by the operation span task. The influence of positive affect on STM, however, was weaker. These results suggest that positive affect enhances WM, a task that involves controlled processing, not just storage processing. Additional analyses of recall and processing times and accuracy further suggest that improved WM under positive affect is not attributable to motivational differences, but results instead from improved controlled cognitive processing.

  13. Rendezvous and Docking for Space Exploration

    Science.gov (United States)

    Machula, M. F.; Crain, T.; Sandhoo, G. S.

    2005-01-01

    To achieve the exploration goals, new approaches to exploration are being envisioned that include robotic networks, modular systems, pre-positioned propellants and in-space assembly in Earth orbit, Lunar orbit and other locations around the cosmos. A fundamental requirement for rendezvous and docking to accomplish in-space assembly exists in each of these locations. While existing systems and technologies can accomplish rendezvous and docking in low earth orbit, and rendezvous and docking with crewed systems has been successfully accomplished in low lunar orbit, our capability must extend toward autonomous rendezvous and docking. To meet the needs of the exploration vision in-space assembly requiring both crewed and uncrewed vehicles will be an integral part of the exploration architecture. This paper focuses on the intelligent application of autonomous rendezvous and docking technologies to meet the needs of that architecture. It also describes key technology investments that will increase the exploration program's ability to ensure mission success, regardless of whether the rendezvous are fully automated or have humans in the loop.

  14. Docking screens: right for the right reasons?

    Science.gov (United States)

    Kolb, Peter; Irwin, John J

    2009-01-01

    Whereas docking screens have emerged as the most practical way to use protein structure for ligand discovery, an inconsistent track record raises questions about how well docking actually works. In its favor, a growing number of publications report the successful discovery of new ligands, often supported by experimental affinity data and controls for artifacts. Few reports, however, actually test the underlying structural hypotheses that docking makes. To be successful and not just lucky, prospective docking must not only rank a true ligand among the top scoring compounds, it must also correctly orient the ligand so the score it receives is biophysically sound. If the correct binding pose is not predicted, a skeptic might well infer that the discovery was serendipitous. Surveying over 15 years of the docking literature, we were surprised to discover how rarely sufficient evidence is presented to establish whether docking actually worked for the right reasons. The paucity of experimental tests of theoretically predicted poses undermines confidence in a technique that has otherwise become widely accepted. Of course, solving a crystal structure is not always possible, and even when it is, it can be a lot of work, and is not readily accessible to all groups. Even when a structure can be determined, investigators may prefer to gloss over an erroneous structural prediction to better focus on their discovery. Still, the absence of a direct test of theory by experiment is a loss for method developers seeking to understand and improve docking methods. We hope this review will motivate investigators to solve structures and compare them with their predictions whenever possible, to advance the field.

  15. Control of plasma position in the CASTOR tokamak

    International Nuclear Information System (INIS)

    Valovic, M.

    1988-11-01

    A simple servo-system designed for plasma position control in the CASTOR tokamak is described. Both radial and vertical plasma displacements were minimized using two servo-loops consisting of detection coils, a conventional electric controller and an amplifier operated as an unipolar voltage-controlled current source. To ensure the optimum conditions in the start-up phase of the discharge, currents in the servo-systems were externally preprogrammed. The prescribed plasma position was maintained with the accuracy of 3 mm. The feedback control improves plasma parameters, e.g. it removes the positional disruption at the end of the tokamak discharge. (J.U.). 4 figs., 3 refs

  16. Car-Like Mobile Robot Oriented Positioning by Fuzzy Controllers

    Directory of Open Access Journals (Sweden)

    Noureddine Ouadah

    2008-11-01

    Full Text Available In this paper, fuzzy logic controllers (FLC are used to implement an efficient and accurate positioning of an autonomous car-like mobile robot, respecting final orientation. To accomplish this task, called "Oriented Positioning", two FLC have been developed: robot positioning controller (RPC and robot following controller (RFC. Computer simulation results illustrate the effectiveness of the proposed technique. Finally, real-time experiments have been made on an autonomous car-like mobile robot called "Robucar", developed to perform people transportation. Obtained results from experiments demonstrate the effectiveness of the proposed control strategy.

  17. Robust Position Control of Electro-mechanical Systems

    OpenAIRE

    Rong Mei; Mou Chen

    2013-01-01

    In this work, the robust position control scheme is proposed for the electro-mechanical system using the disturbance observer and backstepping control method. To the external unknown load of the electro-mechanical system, the nonlinear disturbance observer is given to estimate the external unknown load. Combining the output of the developed nonlinear disturbance observer with backstepping technology, the robust position control scheme is proposed for the electro-mechanical system. The stabili...

  18. Advanced control of piezoelectric micro-nano-positioning systems

    CERN Document Server

    Xu, Qingsong

    2016-01-01

    This book explores emerging methods and algorithms that enable precise control of micro-/nano-positioning systems. The text describes three control strategies: hysteresis-model-based feedforward control and hysteresis-model-free feedback control based on and free from state observation. Each paradigm receives dedicated attention within a particular part of the text. Readers are shown how to design, validate and apply a variety of new control approaches in micromanipulation: hysteresis modelling, discrete-time sliding-mode control and model-reference adaptive control. Experimental results are provided throughout and build up to a detailed treatment of practical applications in the fourth part of the book. The applications focus on control of piezoelectric grippers. Advanced Control of Piezoelectric Micro-/Nano-Positioning Systems will assist academic researchers and practising control and mechatronics engineers interested in suppressing sources of nonlinearity such as hysteresis and drift when combining positi...

  19. Automation of Aditya tokamak plasma position control DC power supply

    Energy Technology Data Exchange (ETDEWEB)

    Arambhadiya, Bharat, E-mail: bharat@ipr.res.in; Raj, Harshita; Tanna, R.L.; Edappala, Praveenlal; Rajpal, Rachana; Ghosh, Joydeep; Chattopadhyay, P.K.; Kalal, M.B.

    2016-11-15

    Highlights: • Plasma position control is very essential for obtaining repeatable high temperature, high-density discharges of longer durations in tokomak. • The present capacitor bank has limitations of maximum current capacity and position control beyond 200 ms. • The installation of a separate set of coils and a DC power supply can control the plasma position beyond 200 ms. • A high power thyristor (T588N1200) triggers for DC current pulse of 300 A fires precisely at required positions to modify plasma position. • The commissioning is done for the automated in-house, quick and reliable solution. - Abstract: Plasma position control is essential for obtaining repeatable high temperature, high-density discharges of longer duration in tokamaks. Recently, a set of external coils is installed in the vertical field mode configuration to control the radial plasma position in ADITYA tokamak. The existing capacitor bank cannot provide the required current pulse beyond 200 ms for position control. This motivated to have a DC power supply of 500 A to provide current pulse beyond 200 ms for the position control. The automatization of the DC power supply mandated interfaces with the plasma control system, Aditya Pulse Power supply, and Data acquisition system for coordinated discharge operation. A high current thyristor circuit and a timer circuit have been developed for controlling the power supply automatically for charging vertical field coils of Aditya tokamak. Key protection interlocks implemented in the development ensure machine and occupational safety. Fiber-optic trans-receiver isolates the power supply with other subsystems, while analog channel is optically isolated. Commissioning and testing established proper synchronization of the power supply with tokamak operation. The paper discusses the automation of the DC power supply with main circuit components, timing control, and testing results.

  20. Development of the 'JFT-2' tokamak plasma position control system

    International Nuclear Information System (INIS)

    Fujisawa, Noboru; Matsuzaki, Yoshimi; Suzuki, Norio; Murai, Katsuji; Suzuki, Satoshi.

    1980-01-01

    Digital control technique was applied to control the plasma position in the JFT-2 tokamak experiment device. The detail of the JFT-2 is described elsewhere. The plasma position control system consists of a Hitachi control computer, HIDIC 80, and a Hitachi micro-computer, HIDIC 08E. The plasma position is detected by the position control computer, and compared with a preset value. Then, a reference signal is supplied to the micro-computer controlling power source, and the phase control of the thyristor controlling power source is performed. Since the behavior of plasma is very fast, the fast control is required. The control of the thyristor controlling power source is made by direct digital control (DDC). The main component of the hardware of the present system is the micro-computer HIDIC 08E. The software is the direct task system without the operating system (OS). The results of experiments showed that the feedback control of the system worked well. (Kato, T.)

  1. Tracking control mechanisms for positioning automatic CRD exchanger

    International Nuclear Information System (INIS)

    Koizumi, Akira; Takada, Satoshi.

    1984-01-01

    Purpose: To enable completely automatic positioning for the automatic CRD (control rod drives) exchanger, as well as shorten the time for the exchanging operation and save the operator's labour. Constitution: Images of a target attached to the lower flange face of CRD are picked up by a fiber scope mounted to a mounting head. The images are converted through I.T.V. into electrical signals, passed through a cable and then sent to a pattern recognition mechanism. The position for the images of the target is calculated and the calculated position is sent to a drive control section, where the position for the images of the target is compared with a reference position for the images (exactly aligned position) and the moving amount of the mounting head is calculated to move the driving section and thereby complete the positioning. (Kawakami, Y.)

  2. Fractional-order positive position feedback compensator for active vibration control of a smart composite plate

    Science.gov (United States)

    Marinangeli, L.; Alijani, F.; HosseinNia, S. Hassan

    2018-01-01

    In this paper, Active Vibration Control (AVC) of a rectangular carbon fibre composite plate with free edges is presented. The plate is subjected to out-of-plane excitation by a modal vibration exciter and controlled by Macro Fibre Composite (MFC) transducers. Vibration measurements are performed by using a Laser Doppler Vibrometer (LDV) system. A fractional-order Positive Position Feedback (PPF) compensator is proposed, implemented and compared to the standard integer-order PPF. MFC actuator and sensor are positioned on the plate based on maximal modal strain criterion, so as to control the second natural mode of the plate. Both integer and fractional-order PPF allowed for the effective control of the second mode of vibration. However, the newly proposed fractional-order controller is found to be more efficient in achieving the same performance with less actuation voltage. Moreover, it shows promising performance in reducing spillover effect due to uncontrolled modes.

  3. Coordinated joint motion control system with position error correction

    Science.gov (United States)

    Danko, George L.

    2016-04-05

    Disclosed are an articulated hydraulic machine supporting, control system and control method for same. The articulated hydraulic machine has an end effector for performing useful work. The control system is capable of controlling the end effector for automated movement along a preselected trajectory. The control system has a position error correction system to correct discrepancies between an actual end effector trajectory and a desired end effector trajectory. The correction system can employ one or more absolute position signals provided by one or more acceleration sensors supported by one or more movable machine elements. Good trajectory positioning and repeatability can be obtained. A two joystick controller system is enabled, which can in some cases facilitate the operator's task and enhance their work quality and productivity.

  4. Digital control of plasma position in Damavand tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Emami, M.; Babazadeh, A.R.; Roshan, M.V.; Memarzadeh, M.; Habibi, H. [Atomic Energy Organization of Iran (AEOI), Tehran (Iran, Islamic Republic of). Nuclear Fusion Research Center. Plasma Physics Lab.

    2002-03-01

    Plasma position control is one of the important issues in the design and operation of tokamak fusion research device. Since a tokamak is basically an electrical system consisting of power supplies, coils, plasma and eddy currents, a model in which these components are treated as an electrical circuits is used in designing Damavand plasma position control system. This model is used for the simulation of the digital control system and its parameters have been verified experimentally. In this paper, the performance of a high-speed digital controller as well as a simulation study and its application to the Damavand tokamak is discussed. (author)

  5. Car-Like Mobile Robot Oriented Positioning by Fuzzy Controllers

    Directory of Open Access Journals (Sweden)

    Noureddine Ouadah

    2008-09-01

    Full Text Available In this paper, fuzzy logic controllers (FLC are used to implement an efficient and accurate positioning of an autonomous car-like mobile robot, respecting final orientation. To accomplish this task, called “Oriented Positioning”, two FLC have been developed: robot positioning controller (RPC and robot following controller (RFC. Computer simulation results illustrate the effectiveness of the proposed technique. Finally, real-time experiments have been made on an autonomous car-like mobile robot called “Robucar”, developed to perform people transportation. Obtained results from experiments demonstrate the effectiveness of the proposed control strategy.

  6. Rendezvous and docking tracker

    Science.gov (United States)

    Ray, Art J.; Ross, Susan E.; Deming, Douglas R.

    1986-01-01

    A conceptual solid-state rendezvous and docking tracker (RDT) has been devised for generating range and attitude data for a docking vehicle relative to a target vehicle. Emphasis is placed on the approach of the Orbiter to a link with the Space Station. Three laser illuminators ring the optical axis of the lens a directed toward retroreflectors on the target vehicle. Each retroreflector is equipped with a bandpass filter for a designated illumination frequency. Data are collected sequentially over a 20 deg field of view as the range closes to 100-1000 m. A fourth ranging retroreflector 0.3 m from center is employed during close-in maneuvers. The system provides tracking data on motions with 6 deg of freedom, and furnishes 500 msec updates (to be enhanced to 100 msec) to the operator at a computer console.

  7. Dynamic Positioning of Ships : A nonlinear control design study

    NARCIS (Netherlands)

    Muhammad, S.

    2012-01-01

    Dynamic positioning (DP) is relatively a new technique used to maintain the position and heading of ships in various offshore operations. Due to the features like better safety and operating efficiency, DP systems are becoming more and more popular. This thesis mainly focusses on the control system

  8. INDOOR POSITIONING AND NAVIGATION BASED ON CONTROL SPHERECAL PANORAMIC IMAGES

    Directory of Open Access Journals (Sweden)

    T.-C. Huang

    2016-06-01

    Full Text Available Continuous indoor and outdoor positioning and navigation is the goal to achieve in the field of mobile mapping technology. However, accuracy of positioning and navigation will be largely degraded in indoor or occluded areas, due to receiving weak or less GNSS signals. Targeting the need of high accuracy indoor and outdoor positioning and navigation for mobile mapping applications, the objective of this study is to develop a novel method of indoor positioning and navigation with the use of spherical panoramic image (SPI. Two steps are planned in the technology roadmap. First, establishing a control SPI database that contains a good number of well-distributed control SPIs pre-acquired in the target space. A control SPI means an SPI with known exterior orientation parameters, which can be solved with a network bundle adjustment of SPIs. Having a control SPI database, the target space will be ready to provide the service of positioning and navigation. Secondly, the position and orientation of a newly taken SPI can be solved by using overlapped SPIs searched from the control SPI database. The method of matching SPIs and finding conjugate image features will be developed and tested. Two experiments will be planned and conducted in this paper to test the feasibility and validate the test results of the proposed methods. Analysis of appropriate number and distribution of needed control SPIs will also be included in the experiments with respect to different test cases.

  9. Position Control of Switched Reluctance Motor Using Super Twisting Algorithm

    Directory of Open Access Journals (Sweden)

    Muhammad Rafiq Mufti

    2016-01-01

    Full Text Available The inherent problem of chattering in traditional sliding mode control is harmful for practical application of control system. This paper pays a considerable attention to a chattering-free control method, that is, higher-order sliding mode (super twisting algorithm. The design of a position controller for switched reluctance motor is presented and its stability is assured using Lyapunov stability theorem. In order to highlight the advantages of higher-order sliding mode controller (HOSMC, a classical first-order sliding mode controller (FOSMC is also applied to the same system and compared. The simulation results reflect the effectiveness of the proposed technique.

  10. Position and Attitude Alternate of Path Tracking Heading Control

    Directory of Open Access Journals (Sweden)

    Baocheng Tan

    2014-03-01

    Full Text Available The path tracking control algorithm is one of the key problems in the control system design of autonomous vehicle. In this paper, we have conducted dynamic modeling for autonomous vehicle, the relationship between course deviation and yaw rate and centroid deflection angle. From the angle of the dynamics and geometrical, this paper have described the path tracking problem, analyzed the emergence of the eight autonomous vehicles pose binding - position and attitude alternate control methods to identify the relationship between posture and the controlling variables, and design a controller, the experimental results verify the feasibility and effectiveness of this control method.

  11. Experimental Study on Position Control System Using Encoderless Magnetic Motion

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Youn; Heo, Hoon [Korea Univ., Seoul (Korea, Republic of); Yun, Young Min; Shim, Ho Keun; Kwon, Young Mok [TPC Mechatronics, Daejeon (Korea, Republic of)

    2016-01-15

    A position control system composed of the PMLSM(Permanent Magnet Linear Synchronous Motor), unlike conventional linear permanent magnet synchronous motor is fixed to the permanent magnet moving coil rails (permanent magnet = stator, coil = mover), the coil is fixed, moving the permanent magnet, we propose a position control system (permanent magnet = mover, coil = stator) structure. Position is measured not using conventional encoder or resolver but by adopting vector control method using 2 hall sensors generating rectangular signal. This method estimate the velocity and position of mover by using the quadruple of two hall sensor signal instead of encoder signal. Vector control of PMLSM using 2 hall sensor generating rectangular wave is proved to control the system stable and efficiently through simulation. Also hardware experiment reveals that the position control performance is measured within the range of 30-50μ in the accuracy of 10-20μ, which is improved twice to the conventional method. The proposed method exhibits its economical efficiency and practical usefulness. The vector control technique using two hall sensors can be installed in narrow place, accordingly it can be implemented on the system where the conventional encoder or resolver cannot operate.

  12. Cylinder Position Servo Control Based on Fuzzy PID

    Directory of Open Access Journals (Sweden)

    Shibo Cai

    2013-01-01

    Full Text Available The arbitrary position control of cylinder has always been the hard challenge in pneumatic system. We try to develop a cylinder position servo control method by combining fuzzy PID with the theoretical model of the proportional valve-controlled cylinder system. The pressure differential equation of cylinder, pressure-flow equation of proportional valve, and moment equilibrium equation of cylinder are established. And the mathematical models of the cylinder driving system are linearized. Then fuzzy PID control algorithm is designed for the cylinder position control, including the detail analysis of fuzzy variables and domain, fuzzy logic rules, and defuzzification. The stability of the proposed fuzzy PID controller is theoretically proved according to the small gain theorem. Experiments for targets position of 250 mm, 300 mm, and 350 mm were done and the results showed that the absolute error of the position control is less than 0.25 mm. And comparative experiment between fuzzy PID and classical PID verified the advantage of the proposed algorithm.

  13. Positive sliding mode control for blood glucose regulation

    Science.gov (United States)

    Menani, Karima; Mohammadridha, Taghreed; Magdelaine, Nicolas; Abdelaziz, Mourad; Moog, Claude H.

    2017-11-01

    Biological systems involving positive variables as concentrations are some examples of so-called positive systems. This is the case of the glycemia-insulinemia system considered in this paper. To cope with these physical constraints, it is shown that a positive sliding mode control (SMC) can be designed for glycemia regulation. The largest positive invariant set (PIS) is obtained for the insulinemia subsystem in open and closed loop. The existence of a positive SMC for glycemia regulation is shown here for the first time. Necessary conditions to design the sliding surface and the discontinuity gain are derived to guarantee a positive SMC for the insulin dynamics. SMC is designed to be positive everywhere in the largest closed-loop PIS of plasma insulin system. Two-stage SMC is employed; the last stage SMC2 block uses the glycemia error to design the desired insulin trajectory. Then the plasma insulin state is forced to track the reference via SMC1. The resulting desired insulin trajectory is the required virtual control input of the glycemia system to eliminate blood glucose (BG) error. The positive control is tested in silico on type-1 diabetic patients model derived from real-life clinical data.

  14. Motivation enhances control of positive and negative emotional distractions.

    Science.gov (United States)

    Walsh, Amy T; Carmel, David; Harper, David; Grimshaw, Gina M

    2018-01-03

    Using cognitive control to ignore distractions is essential for successfully achieving our goals. In emotionally-neutral contexts, motivation can reduce interference from irrelevant stimuli by enhancing cognitive control. However, attention is commonly biased towards emotional stimuli, making them potent distractors. Can motivation aid control of emotional distractions, and does it do so similarly for positive and negative stimuli? Here, we examined how task motivation influences control of distraction from positive, negative, and neutral scenes. Participants completed a simple perceptual task while attempting to ignore task-irrelevant images. One group received monetary reward for fast and accurate task performance; another (control) group did not. Overall, both negative (mutilation) and positive (erotic) images caused greater slowing of responses than neutral images of people, but emotional distraction was reduced with reward. Crucially, despite the different motivational directions associated with negative and positive stimuli, reward reduced negative and positive distraction equally. Our findings suggest that motivation may encourage the use of a sustained proactive control strategy that can effectively reduce the impact of emotional distraction.

  15. Consensus positive position feedback control for vibration attenuation of smart structures

    Science.gov (United States)

    Omidi, Ehsan; Nima Mahmoodi, S.

    2015-04-01

    This paper presents a new network-based approach for active vibration control in smart structures. In this approach, a network with known topology connects collocated actuator/sensor elements of the smart structure to one another. Each of these actuators/sensors, i.e., agent or node, is enhanced by a separate multi-mode positive position feedback (PPF) controller. The decentralized PPF controlled agents collaborate with each other in the designed network, under a certain consensus dynamics. The consensus constraint forces neighboring agents to cooperate with each other such that the disagreement between the time-domain actuation of the agents is driven to zero. The controller output of each agent is calculated using state-space variables; hence, optimal state estimators are designed first for the proposed observer-based consensus PPF control. The consensus controller is numerically investigated for a flexible smart structure, i.e., a thin aluminum beam that is clamped at its both ends. Results demonstrate that the consensus law successfully imposes synchronization between the independently controlled agents, as the disagreements between the decentralized PPF controller variables converge to zero in a short time. The new consensus PPF controller brings extra robustness to vibration suppression in smart structures, where malfunctions of an agent can be compensated for by referencing the neighboring agents’ performance. This is demonstrated in the results by comparing the new controller with former centralized PPF approach.

  16. Optimising position control of a solar parabolic trough

    Directory of Open Access Journals (Sweden)

    Puramanathan Naidoo

    2011-03-01

    Full Text Available In today’s climate of growing energy needs and increasing environmental concerns, alternatives to the use of non-renewable and polluting fossil fuels have to be investigated. One such alternative is solar energy. This study is based on the implementation of a mathematical computation – the PSA (Plataforma Solar de Almeria computation developed at PSA (the European Test Centre for solar energy applications – embedded in a control algorithm to locate the position of the sun. Tests were conducted on a solar parabolic trough (SPT constructed at the Solar Thermal Applications Research Laboratory of the Mangosuthu University of Technology (Durban, South Africa for optimal position control using the PSA value. The designed control algorithm embedded in an industrial Siemens S7-314 C-2PtP programmable logic controller compared the PSA computation to a measured position of the SPT to optimally rotate the SPT to a desired position with the constant movement of the sun. The two main angles of the sun relative to the position of the SPT on earth, the zenith angle and the azimuth angle, both calculated in the PSA from the vertical and horizontal planes, respectively, were applied to the control algorithm to generate an appropriate final tracking angle within a 0.007 radian (0° 24′ 3.6″ tolerance, in accordance to the construction specifications and solar collector testing standards of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE, 1991. These values, together with the longitude and latitude applicable to the geographical location of the SPT, were processed in the control software to rotate the SPT to an optimal position with respect to the position of the sun in its daily path, for solar-to-thermal conversion.

  17. Selective control of attention supports the positivity effect in aging.

    Directory of Open Access Journals (Sweden)

    Laura K Sasse

    Full Text Available There is emerging evidence for a positivity effect in healthy aging, which describes an age-specific increased focus on positive compared to negative information. Life-span researchers have attributed this effect to the selective allocation of cognitive resources in the service of prioritized emotional goals. We explored the basic principles of this assumption by assessing selective attention and memory for visual stimuli, differing in emotional content and self-relevance, in young and old participants. To specifically address the impact of cognitive control, voluntary attentional selection during the presentation of multiple-item displays was analyzed and linked to participants' general ability of cognitive control. Results revealed a positivity effect in older adults' selective attention and memory, which was particularly pronounced for self-relevant stimuli. Focusing on positive and ignoring negative information was most evident in older participants with a generally higher ability to exert top-down control during visual search. Our findings highlight the role of controlled selectivity in the occurrence of a positivity effect in aging. Since the effect has been related to well-being in later life, we suggest that the ability to selectively allocate top-down control might represent a resilience factor for emotional health in aging.

  18. Selective control of attention supports the positivity effect in aging.

    Science.gov (United States)

    Sasse, Laura K; Gamer, Matthias; Büchel, Christian; Brassen, Stefanie

    2014-01-01

    There is emerging evidence for a positivity effect in healthy aging, which describes an age-specific increased focus on positive compared to negative information. Life-span researchers have attributed this effect to the selective allocation of cognitive resources in the service of prioritized emotional goals. We explored the basic principles of this assumption by assessing selective attention and memory for visual stimuli, differing in emotional content and self-relevance, in young and old participants. To specifically address the impact of cognitive control, voluntary attentional selection during the presentation of multiple-item displays was analyzed and linked to participants' general ability of cognitive control. Results revealed a positivity effect in older adults' selective attention and memory, which was particularly pronounced for self-relevant stimuli. Focusing on positive and ignoring negative information was most evident in older participants with a generally higher ability to exert top-down control during visual search. Our findings highlight the role of controlled selectivity in the occurrence of a positivity effect in aging. Since the effect has been related to well-being in later life, we suggest that the ability to selectively allocate top-down control might represent a resilience factor for emotional health in aging.

  19. Optimal Rendezvous and Docking Simulator for Elliptical Orbits, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — It is proposed to develop and implement a simulation of spacecraft rendezvous and docking guidance, navigation, and control in elliptical orbit. The foundation of...

  20. A digital position-indication system for control rods

    International Nuclear Information System (INIS)

    Nishizawa, Yukio; Hayakawa, Toshifumi

    1979-01-01

    Systems that detect and indicate the position of the control rods that regulate the thermal output of a nuclear reactor play a particularly important role in monitoring its operational status. Conventionally, control rod position indication in pressurized water reactors has been of the analog type, utilizing the principle of the differential transformer. The present digital system was developed with the objective of achieving greater stability, greater accuracy, and higher reliability. The article gives a general description of the system and describes its advantages. (author)

  1. DockingShop: A Tool for Interactive Molecular Docking

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ting-Cheng; Max, Nelson L.; Ding, Jinhui; Bethel, E. Wes; Crivelli, Silvia N.

    2005-04-24

    Given two independently determined molecular structures, the molecular docking problem predicts the bound association, or best fit between them, while allowing for conformational changes of the individual molecules during construction of a molecular complex. Docking Shop is an integrated environment that permits interactive molecular docking by navigating a ligand or protein to an estimated binding site of a receptor with real-time graphical feedback of scoring factors as visual guides. Our program can be used to create initial configurations for a protein docking prediction process. Its output--the structure of aprotein-ligand or protein-protein complex--may serve as an input for aprotein docking algorithm, or an optimization process. This tool provides molecular graphics interfaces for structure modeling, interactive manipulation, navigation, optimization, and dynamic visualization to aid users steer the prediction process using their biological knowledge.

  2. Operator learning effects in teleoperated rendezvous & docking

    Science.gov (United States)

    Wilde, M.; Harder, J.; Purschke, R.

    Teleoperation of spacecraft proximity operations and docking requires delicate timing and coordination of spacecraft maneuvers. Experience has shown that human operators show large performance fluctuations in these areas, which are a major factor to be addressed in operator training. In order to allow the quantification of the impact of these human fluctuations on control system performance and the human perception of this performance, a learning curve study was conducted with teleoperated final approach and docking scenarios. Over a period of ten experiment days, three test participants were tasked with repeatedly completing a set of three training scenarios. The scenarios were designed to contain different combinations of the major elements of any final approach and docking situation, and to feature an increasing difficulty level. The individual difficulty levels for the three operators furthermore differed in the level of operator support functions available in their human-machine interfaces. Operator performance in the test scenarios were evaluated in the fields approach success and precision, docking safety, and approach efficiency by a combination of recorded maneuver data and questionnaires. The results show that operator experience and the associated learning curves increase operator performance substantially, regardless of the support system used. The paper also shows that the fluctuations in operator performance and self-perception are substantial between as well as within experiment days, and must be reckoned with in teleoperation system design and mission planning.

  3. Stability of position control system in JIPP T-II

    International Nuclear Information System (INIS)

    Sakurai, Keiichi; Tanahashi, Shygo

    1980-01-01

    Computations and experiments on the stability of a feedback control system for maintaining a plasma column in equilibrium are described. The time response of the displacement of the plasma to the desired position is examined by solving the equation of motion of the plasma column. We show that the stability of the feedback control system is improved by using an additional term which represents the shift velocity of the plasma column. (author)

  4. The position control of a capsule filled with magnetic fluid

    International Nuclear Information System (INIS)

    Rhee, E.J.; Park, M.K.; Yamane, R.; Oshima, S.

    2002-01-01

    In this paper, in order to establish the technique of a nozzle-flapper system of a servo valve using magnetic fluid in hydraulic system, a governing equation regarding the levitation of a capsule filled with magnetic fluid is formulated. Using PID control, an experiment for the position control of a capsule was performed. The experimental results were compared with the simulation results found by the governing equation

  5. Peer Positive Social Control and Men's Health-Promoting Behaviors.

    Science.gov (United States)

    Houle, Janie; Meunier, Sophie; Coulombe, Simon; Mercerat, Coralie; Gaboury, Isabelle; Tremblay, Gilles; de Montigny, Francine; Cloutier, Lyne; Roy, Bernard; Auger, Nathalie; Lavoie, Brigitte

    2017-09-01

    Men are generally thought to be less inclined to take care of their health. To date, most studies about men's health have focused on deficits in self-care and difficulties in dealing with this sphere of their life. The present study reframes this perspective, using a salutogenic strengths-based approach and seeking to identify variables that influence men to take care of their health, rather than neglect it. This study focuses on the association between peer positive social control and men's health behaviors, while controlling for other important individual and social determinants (sociodemographic characteristics, health self-efficacy, home neighborhood, spousal positive social control, and the restrictive emotionality norm). In a mixed-method study, 669 men answered a self-reported questionnaire, and interviews were conducted with a maximum variation sample of 31 men. Quantitative results indicated that, even after controlling for sociodemographic variables and other important factors, peer positive social control was significantly associated with the six health behaviors measured in the study (health responsibility, nutrition, physical activity, interpersonal relations, stress management, and spirituality). Interview results revealed that peer positive social control influenced men's health behaviors through three different mechanisms: shared activity, being inspired, and serving as a positive role model for others. In summary, friends and coworkers could play a significant role in promoting various health behaviors among adult men in their daily life. Encouraging men to socialize and discuss health, and capitalizing on healthy men as role models appear to be effective ways to influence health behavior adoption among this specific population.

  6. Structure of the automatic system for plasma equilibrium position control

    International Nuclear Information System (INIS)

    Gubarev, V.F.; Krivonos, Yu.G.; Samojlenko, Yu.I.; Snegur, A.A.

    1978-01-01

    Considered are the principles of construction of the automatic system for plasma filament equilibrium position control inside the discharge chamber for the installation of a tokamak type. The combined current control system in control winding is suggested. The most powerful subsystem creates current in the control winding according to the program calculated beforehand. This system provides plasma rough equilibrium along the ''big radius''. The subsystem performing the current change in small limits according to the principle of feed-back coupling is provided simultaneously. The stabilization of plasma position is achieved in the discharge chamber. The advantage of construction of such system is in decreasing of the automatic requlator power without lowering the requirements to the accuracy of equilibrium preservation. The subsystem of automatic control of plasma position over the vertical is put into the system. Such an approach to the construction of the automatic control system proves to be correct; it is based on the experience of application of similar devices for some existing thermonuclear plants

  7. Position and attitude tracking control for a quadrotor UAV.

    Science.gov (United States)

    Xiong, Jing-Jing; Zheng, En-Hui

    2014-05-01

    A synthesis control method is proposed to perform the position and attitude tracking control of the dynamical model of a small quadrotor unmanned aerial vehicle (UAV), where the dynamical model is underactuated, highly-coupled and nonlinear. Firstly, the dynamical model is divided into a fully actuated subsystem and an underactuated subsystem. Secondly, a controller of the fully actuated subsystem is designed through a novel robust terminal sliding mode control (TSMC) algorithm, which is utilized to guarantee all state variables converge to their desired values in short time, the convergence time is so small that the state variables are acted as time invariants in the underactuated subsystem, and, a controller of the underactuated subsystem is designed via sliding mode control (SMC), in addition, the stabilities of the subsystems are demonstrated by Lyapunov theory, respectively. Lastly, in order to demonstrate the robustness of the proposed control method, the aerodynamic forces and moments and air drag taken as external disturbances are taken into account, the obtained simulation results show that the synthesis control method has good performance in terms of position and attitude tracking when faced with external disturbances. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  8. a positive control plasmid for reporter gene assay

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-04

    Jul 4, 2008 ... qualification as a positive control for luciferase reporter gene assays. Key words: Reporter gene plasmid, luciferase assay, cytomegalovirus promoter/enhancer, human melanoma cell line. INTRODUCTION. Reporter genes, often called reporters, have become a precious tool in studies of gene expression ...

  9. The plasma position control of ITER EDA plasma

    International Nuclear Information System (INIS)

    Senda, Ikuo; Nishio, Satoshi; Tsunematsu, Toshihide; Nishino, Toru; Fujieda, Hirobumi.

    1994-09-01

    The study on the plasma position control of ITER EDA performed by Japan Home Team during the sensitivity study in 1994 is summarized. The controllabilities of plasmas in the Outline Design and elongated version are compared. The model used to describe the motion of the plasma is a rigid model. The PD feedback control is applied with respect to the displacements of the plasma from the equilibrium. Three types of fluctuations, which initiate the motion of the plasma, are examined, namely a finite horizontal fluctuation field, a small horizontal fluctuation field such that the motion of the plasma is governed by the passive structures and an abrupt change of the poloidal beta β p and internal inductance l i . In the simulations of finite horizontal fluctuation fields, controls depend on the strength of the fluctuations, for instance, 3-5V is needed for 5-10G of fluctuation fields in the Outline Design. When the fluctuation field is small and the plasma displacement grows in a characteristic time of the passive structures, a few volt of the control voltage is enough to obtain good controllability. It is shown that the control when (β p , l i ) changes simultaneously is demanding and a large control voltage is required to maintain satisfactory control. Comparing the elongated version with the Outline Design, the control voltage which is larger than the Outline Design by a factor of 2-3 is required to obtain the same controllability in the elongated version. (author)

  10. Position Control of a 3-CPU Spherical Parallel Manipulator

    Directory of Open Access Journals (Sweden)

    Massimo Callegari

    2013-01-01

    Full Text Available The paper presents the first experimental results on the control of a prototypal robot designed for the orientation of parts or tools. The innovative machine is a spherical parallel manipulator actuated by 3 linear motors; several position control schemes have been tested and compared with the final aim of designing an interaction controller. The relative simplicity of machine kinematics allowed to test algorithms requiring the closed-loop evaluation of both inverse and direct kinematics; the compensation of gravitational terms has been experimented as well.

  11. Signal differentiation in position tracking control of dc motors

    International Nuclear Information System (INIS)

    Beltran-Carbajal, F; Valderrabano-Gonzalez, A; Rosas-Caro, J C

    2015-01-01

    An asymptotic differentiation approach with respect to time is used for on-line estimation of velocity and acceleration signals in controlled dc motors. The attractive feature of this differentiator of signals is that it does not require any system mathematical model, which allows its use in engineering systems that require the signal differentiation for its control, identification, fault detection, among other applications. Moreover, it is shown that the differentiation approach can be applied for output signals showing a chaotic behavior. In addition a differential flatness control scheme with additional integral compensation of the output error is proposed for tracking tasks of position reference trajectories for direct current electric motors using angular position measurements only

  12. Nonlinear control of ships minimizing the position tracking errors

    Directory of Open Access Journals (Sweden)

    Svein P. Berge

    1999-07-01

    Full Text Available In this paper, a nonlinear tracking controller with integral action for ships is presented. The controller is based on state feedback linearization. Exponential convergence of the vessel-fixed position and velocity errors are proven by using Lyapunov stability theory. Since we only have two control devices, a rudder and a propeller, we choose to control the longship and the sideship position errors to zero while the heading is stabilized indirectly. A Virtual Reference Point (VRP is defined at the bow or ahead of the ship. The VRP is used for tracking control. It is shown that the distance from the center of rotation to the VRP will influence on the stability of the zero dynamics. By selecting the VRP at the bow or even ahead of the bow, the damping in yaw can be increased and the zero dynamics is stabilized. Hence, the heading angle will be less sensitive to wind, currents and waves. The control law is simulated by using a nonlinear model of the Japanese training ship Shiojimaru with excellent results. Wind forces are added to demonstrate the robustness and performance of the integral controller.

  13. A deterministic - approach controller design for electrohydraulic position servo control system

    International Nuclear Information System (INIS)

    Johari Osman

    2000-01-01

    This paper is concerned with the design of a tracking controller for controlling electrohydraulic position servo system based on a deterministic approach. The system is treated as an uncertain system with bounded uncertainties where the bounds are assumed known. It will be shown that the electrohydraulic position servo systems with the proposed controller is practically stable and tracks the desired position in spite of the uncertainties and nonlinearities present in the system (author)

  14. Could positive affect help engineer robot control systems?

    Science.gov (United States)

    Quirin, Markus; Hertzberg, Joachim; Kuhl, Julius; Stephan, Achim

    2011-11-01

    Emotions have long been seen as counteracting rational thought, but over the last decades, they have been viewed as adaptive processes to optimize human (but also animal) behaviour. In particular, positive affect appears to be a functional aspect of emotions closely related to that. We argue that positive affect as understood in Kuhl's PSI model of the human cognitive architecture appears to have an interpretation in state-of-the-art hybrid robot control architectures, which might help tackle some open questions in the field.

  15. Position Mooring Control Based on a Structural Reliability Criterion

    DEFF Research Database (Denmark)

    Fang, Shaoji; Leira, Bernt J.; Blanke, Mogens

    2013-01-01

    is achieved using structural reliability indices in a cost function, where both the mean mooring-line tension and dynamic effects are considered. An optimal set-point is automatically produced without need for manual interaction. The parameters of the extreme value distribution are calculated on-line thereby...... mooring lines simultaneously from exceeding a stress threshold, this paper suggests a new algorithm to determine the reference position and an associated control system. The safety of each line is assessed through a structural reliability index. A reference position where all mooring lines are safe...

  16. Continuous, saturation, and discontinuous tokamak plasma vertical position control systems

    Energy Technology Data Exchange (ETDEWEB)

    Mitrishkin, Yuri V., E-mail: y_mitrishkin@hotmail.com [M. V. Lomonosov Moscow State University, Faculty of Physics, Moscow 119991 (Russian Federation); Pavlova, Evgeniia A., E-mail: janerigoler@mail.ru [M. V. Lomonosov Moscow State University, Faculty of Physics, Moscow 119991 (Russian Federation); Kuznetsov, Evgenii A., E-mail: ea.kuznetsov@mail.ru [Troitsk Institute for Innovation and Fusion Research, Moscow 142190 (Russian Federation); Gaydamaka, Kirill I., E-mail: k.gaydamaka@gmail.com [V. A. Trapeznikov Institute of Control Sciences of the Russian Academy of Sciences, Moscow 117997 (Russian Federation)

    2016-10-15

    Highlights: • Robust new linear state feedback control system for tokamak plasma vertical position. • Plasma vertical position relay control system with voltage inverter in sliding mode. • Design of full models of multiphase rectifier and voltage inverter. • First-order unit approximation of full multiphase rectifier model with high accuracy. • Wider range of unstable plant parameters of stable control system with multiphase rectifier. - Abstract: This paper is devoted to the design and comparison of unstable plasma vertical position control systems in the T-15 tokamak with the application of two types of actuators: a multiphase thyristor rectifier and a transistor voltage inverter. An unstable dynamic element obtained by the identification of plasma-physical DINA code was used as the plasma model. The simplest static feedback state space control law was synthesized as a linear combination of signals accessible to physical measurements, namely the plasma vertical displacement, the current, and the voltage in a horizontal field coil, to solve the pole placement problem for a closed-loop system. Only one system distinctive parameter was used to optimize the performance of the feedback system, viz., a multiple real pole. A first-order inertial unit was used as the rectifier model in the feedback. A system with a complete rectifier model was investigated as well. A system with the voltage inverter model and static linear controller was brought into a sliding mode. As this takes place, real time delays were taken into account in the discontinuous voltage inverter model. The comparison of the linear and sliding mode systems showed that the linear system enjoyed an essentially wider range of the plant model parameters where the feedback system was stable.

  17. Continuous, saturation, and discontinuous tokamak plasma vertical position control systems

    International Nuclear Information System (INIS)

    Mitrishkin, Yuri V.; Pavlova, Evgeniia A.; Kuznetsov, Evgenii A.; Gaydamaka, Kirill I.

    2016-01-01

    Highlights: • Robust new linear state feedback control system for tokamak plasma vertical position. • Plasma vertical position relay control system with voltage inverter in sliding mode. • Design of full models of multiphase rectifier and voltage inverter. • First-order unit approximation of full multiphase rectifier model with high accuracy. • Wider range of unstable plant parameters of stable control system with multiphase rectifier. - Abstract: This paper is devoted to the design and comparison of unstable plasma vertical position control systems in the T-15 tokamak with the application of two types of actuators: a multiphase thyristor rectifier and a transistor voltage inverter. An unstable dynamic element obtained by the identification of plasma-physical DINA code was used as the plasma model. The simplest static feedback state space control law was synthesized as a linear combination of signals accessible to physical measurements, namely the plasma vertical displacement, the current, and the voltage in a horizontal field coil, to solve the pole placement problem for a closed-loop system. Only one system distinctive parameter was used to optimize the performance of the feedback system, viz., a multiple real pole. A first-order inertial unit was used as the rectifier model in the feedback. A system with a complete rectifier model was investigated as well. A system with the voltage inverter model and static linear controller was brought into a sliding mode. As this takes place, real time delays were taken into account in the discontinuous voltage inverter model. The comparison of the linear and sliding mode systems showed that the linear system enjoyed an essentially wider range of the plant model parameters where the feedback system was stable.

  18. Plasma position and shape control device for thermonuclear device

    International Nuclear Information System (INIS)

    Takeuchi, Kazuhiro; Abe, Mitsushi; Kinoshita, Shigemi.

    1993-01-01

    A plasma position and shape control system is constituted with a measuring device, a quenching probability calculation section and a control calculation section. A quenching probability is calculated in the quenching probability calculation section by using a measuring data on temperature, electric current and magnetic field of superconductive coils, based on a margin upto a limit value. The control calculation section selects a control method which decreases applied voltage or current instruction value as the quenching probability of the coils is higher. Since the quenching probability of the superconductive coils can be forecast and a state of low quenching danger can be selected, the safety of the device is improved. When the quenching danger is allowed to a predetermined value, a wide operation region can be provided. (N.H.)

  19. Improved Position Sensor for Feedback Control of Levitation

    Science.gov (United States)

    Hyers, Robert; Savage, Larry; Rogers, Jan

    2004-01-01

    An improved optoelectronic apparatus has been developed to provide the position feedback needed for controlling the levitation subsystem of a containerless-processing system. As explained, the advantage of this apparatus over prior optoelectronic apparatuses that have served this purpose stems from the use of an incandescent lamp, instead of a laser, to illuminate the levitated object. In containerless processing, a small object to be processed is levitated (e.g., by use of a microwave, low-frequency electromagnetic, electrostatic, or acoustic field) so that it is not in contact with the wall of the processing chamber or with any other solid object during processing. In the case of electrostatic or low-frequency electromagnetic levitation, real-time measurement of the displacement of the levitated object from its nominal levitation position along the vertical axis (and, in some cases, along one or two horizontal axes) is needed for feedback control of the levitating field.

  20. Using Positive Deviance for Determining Successful Weight-Control Practices

    Science.gov (United States)

    Stuckey, Heather L.; Boan, Jarol; Kraschnewski, Jennifer L.; Miller-Day, Michelle; Lehman, Erik B.; Sciamanna, Christopher N.

    2013-01-01

    Based on positive deviance (examining the practices of successful individuals), we identified five primary themes from 36 strategies that help to maintain long-term weight loss (weight control) in 61 people. We conducted in-depth interviews to determine what successful individuals did and/or thought about regularly to control their weight. The themes included weight-control practices related to (a) nutrition: increase water, fruit, and vegetable intake, and consistent meal timing and content; (b) physical activity: follow and track an exercise routine at least 3×/week; (c) restraint: practice restraint by limiting and/or avoiding unhealthy foods; (d) self-monitor: plan meals, and track calories/weight progress; and (e) motivation: participate in motivational programs and cognitive processes that affect weight-control behavior. Using the extensive data involving both the practices and practice implementation, we used positive deviance to create a comprehensive list of practices to develop interventions for individuals to control their weight. PMID:20956609

  1. Position Control of Linear Synchronous Motor Drives with Exploitation of Forced Dynamics Control Principles

    Directory of Open Access Journals (Sweden)

    Jan Vittek

    2004-01-01

    Full Text Available Closed-loop position control of mechanisms directly driven by linear synchronous motors with permanent magnets is presented. The control strategy is based on forced dynamic control, which is a form of feedback linearisation, yielding a non-liner multivariable control law to obtain a prescribed linear speed dynamics together with the vector control condition of mutal orthogonality between the stator current and magnetic flux vectors (assuming perfect estimates of the plant parameters. Outer position control loop is closed via simple feedback with proportional gain. Simulations of the design control sysstem, including the drive with power electronic switching, predict the intended drive performance.

  2. Positive and negative dimensions of weight control motivation.

    Science.gov (United States)

    Stotland, S; Larocque, M; Sadikaj, G

    2012-01-01

    This study examined weight control motivation among patients (N=5460 females and 547 males) who sought weight loss treatment with family physicians. An eight-item measure assessed the frequency of thoughts and feelings related to weight control "outcome" (e.g. expected physical and psychological benefits) and "process" (e.g. resentment and doubt). Factor analysis supported the existence of two factors, labeled Positive and Negative motivation. Positive motivation was high (average frequency of thoughts about benefits was 'every day') and stable throughout treatment, while Negative motivation declined rapidly and then stabilized. The determinants of changes in the Positive and Negative dimensions during treatment were examined within 3 time frames: first month, months 2-6, and 6-12. Maintenance of high scores on Positive motivation was associated with higher BMI and more disturbed eating habits. Early reductions in Negative motivation were greater for those starting treatment with higher weight and more disturbed eating habits, but less depression and stress, while later reductions in Negative motivation were predicted by improvements in eating habits, weight, stress and perfectionism. Clinicians treating obesity should be sensitive to fluctuations in both motivational dimensions, as they are likely to play a central role in determining long-term behavior and weight change. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. A randomized controlled trial of positioning treatments in infants with positional head shape deformities.

    Science.gov (United States)

    Hutchison, B Lynne; Stewart, Alistair W; De Chalain, Tristan B; Mitchell, Edwin A

    2010-10-01

    Randomized controlled trials of treatment for deformational plagiocephaly and brachycephaly have been lacking in the literature. Infants (n = 126) presenting to a plagiocephaly clinic were randomized to either positioning strategies or to positioning plus the use of a Safe T Sleep™ positioning wrap. Head shape was measured using a digital photographic technique, and neck function was assessed. They were followed up at home 3, 6 and 12 months later. There was no difference in head shape outcomes for the two treatment groups after 12 months of follow-up, with 42% of infants having head shapes in the normal range by that time. Eighty per cent of children showed good improvement. Those that had poor improvement were more likely to have both plagiocephaly and brachycephaly and to have presented later to clinic. Most infants improved over the 12-month study period, although the use of a sleep positioning wrap did not increase the rate of improvement. © 2010 The Author(s)/Journal Compilation © 2010 Foundation Acta Paediatrica.

  4. Plasma position control in a tokamak reactor around ignition

    International Nuclear Information System (INIS)

    Carretta, U.; Minardi, E.; Bacelli, N.

    1986-01-01

    Plasma position control in a tokamak reactor in the phase approaching ignition is closely related to burn control. If ignited burn corresponds to a thermally unstable situation the plasma becomes sensitive to the thermal instability already in the phase when ignition is approached so that the trajectory in the position-pressure (R,p) space becomes effectively unpredictable. For example, schemes involving closed cycles around ignition can be unstable in the heating-cooling phases, and the deviations may be cumulative in time. Reliable plasma control in pressure-position (p, R) space is achieved by beforehand constraining the p, R trajectory rigidly with suitable feedback vertical field stabilization, which is to be established already below ignition. A scheme in which ignition is approached in a stable and automatic way by feedback stabilization on the vertical field is proposed and studied in detail. The values of the gain coefficient ensuring stabilization and the associated p and R excursions are discussed both analytically, with a 0-D approximation including non-linear effects, and numerically with a 1-D code in cylindrical geometry. Profile effects increase the excursions, in particular above ignition. (author)

  5. Position Control of an X4-Flyer Using a Tether

    Directory of Open Access Journals (Sweden)

    , Keigo Watanabe

    2014-10-01

    Full Text Available In Japan, aging of infrastructures, such as roads, bridges, and water and sewer services, etc. poses a problem, and it is required to extend the life-span of such infrastructures by maintenance. Among infrastructures, especially bridges are periodically inspected by short range visual observations, which check the damage and deterioration of the surface. However, since there are some cases where the short range visual observation is difficult, an alternative method is required so as to replace the short range visual observation with it. So, "X4-Flyer" is very attractive because of realizing a movement at high altitude easily. The objective of this study is to develop a tethered X4- Flyer, so that the conventional short range visual observation of bridges is replaced by it. In this paper, a method for the measurement and control of the position is described by using a tether for controlling the position of the X4-Flyer. In addition, it is checked whether the tethered X4-Flyer can control the position using the proposed method or not, letting it fly in a state in which a tether is being attached.

  6. Strategies for the plasma position and shape control in IGNITOR

    International Nuclear Information System (INIS)

    Ramogida, G.; Alladio, F.; Albanese, R.

    2006-01-01

    The control of the plasma position and shape is a crucial issue in IGNITOR as in every compact, high field, elongated tokamak. The capability of the Poloidal Field Coil system, as presently designed, to provide an effective vertical stabilization of the plasma has been investigated using the CREATE L response model [R. Albanese, F. Villone, '' The Linearized CREATE L Plasma Response Model for the Control of Current, Position and Shape in Tokamaks '', Nucl. Fus., vol. 38, p. 723 (1998)]. This linearized MHD model assumes an axisymmetric deformable plasma described by few global parameters. An optimization of the vertical position control strategy has been carried out and the most effective coil combination has been selected to stabilize the plasma while fulfilling engineering constraints on the coils and minimizing the required power and voltage. The two pairs of coils selected for the vertical control will be fed up with up-down anti-symmetric currents provided by a dedicated supply and overlapped to the scenario currents. The growth rate of the vertical instability and the power required by the active stabilization system have been estimated with this model, indicating that it is possible to design a control system able to guarantee a stability region that includes the most interesting operation conditions. An assessment of the requirements for the plasma cross section shape control has been carried out considering independent perturbations of the plasma global parameters as disturbances and showing that the undesired shape modification rejection is possible with the present PFC and power supply system. The PF coils have been ranked with respect to their capability to restore the shape modifications due to different plasma disturbances and the most effective coil combination, that minimizes recovery time and voltage required, has been selected. In order to have additional means to monitor and control the centre of the plasma column, under demanding conditions

  7. Position Control of the Single Spherical Wheel Mobile Robot by Using the Fuzzy Sliding Mode Controller

    Directory of Open Access Journals (Sweden)

    Hamed Navabi

    2017-01-01

    Full Text Available A spherical wheel robot or Ballbot—a robot that balances on an actuated spherical ball—is a new and recent type of robot in the popular area of mobile robotics. This paper focuses on the modeling and control of such a robot. We apply the Lagrangian method to derive the governing dynamic equations of the system. We also describe a novel Fuzzy Sliding Mode Controller (FSMC implemented to control a spherical wheel mobile robot. The nonlinear nature of the equations makes the controller nontrivial. We compare the performance of four different fuzzy controllers: (a regulation with one signal, (b regulation and position control with one signal, (c regulation and position control with two signals, and (d FSMC for regulation and position control with two signals. The system is evaluated in a realistic simulation and the robot parameters are chosen based on a LEGO platform, so the designed controllers have the ability to be implemented on real hardware.

  8. Predictive IP controller for robust position control of linear servo system.

    Science.gov (United States)

    Lu, Shaowu; Zhou, Fengxing; Ma, Yajie; Tang, Xiaoqi

    2016-07-01

    Position control is a typical application of linear servo system. In this paper, to reduce the system overshoot, an integral plus proportional (IP) controller is used in the position control implementation. To further improve the control performance, a gain-tuning IP controller based on a generalized predictive control (GPC) law is proposed. Firstly, to represent the dynamics of the position loop, a second-order linear model is used and its model parameters are estimated on-line by using a recursive least squares method. Secondly, based on the GPC law, an optimal control sequence is obtained by using receding horizon, then directly supplies the IP controller with the corresponding control parameters in the real operations. Finally, simulation and experimental results are presented to show the efficiency of proposed scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Strategies for the plasma position and shape control in IGNITOR

    International Nuclear Information System (INIS)

    Villone, F.; Albanese, R.; Ambrosino, G.; Pironti, A.; Rubinacci, G.; Ramogida, G.; Alladio, F.; Bombarda, F.; Coletti, A.; Cucchiaro, A.; Maddaluno, G.; Pizzicaroli, G.; Pizzuto, A.; Roccella, M.; Santinelli, M.; Coppi, B.

    2007-01-01

    The capability of the poloidal field coil system, as presently designed, to provide an effective vertical stabilization of the plasma in the IGNITOR machine has been investigated using the CREATE L response model. An optimization of the vertical position control strategy has been carried out and the most effective coil combination has been selected to stabilize the plasma while fulfilling engineering constraints on the coils and minimizing the required power and voltage. The growth rate of the vertical instability and the power required by the active stabilization system has been estimated with this model. The possible failure of the relevant electromagnetic diagnostics has been taken into account, evaluating the robustness of the plasma position reconstruction strategy. A realistic description of the power supply system has permitted to carry out the optimization of the proportional-integrative-derivative (PID) controller, both with a voltage and a current loop control scheme. An assessment of the requirements for the plasma cross section shape control has been carried out considering perturbations of the plasma global parameters independent of each other and showing that the undesired shape modification rejection is possible with the present PFC and power supply system. The PF coils have been rated relative to their capability to restore shape modifications due to different plasma disturbances. The most effective coil combination, that minimizes recovery time and voltage required, has been identified

  10. Cell adhesion controlled by adhesion G protein-coupled receptor GPR124/ADGRA2 is mediated by a protein complex comprising intersectins and Elmo-Dock.

    Science.gov (United States)

    Hernández-Vásquez, Magda Nohemí; Adame-García, Sendi Rafael; Hamoud, Noumeira; Chidiac, Rony; Reyes-Cruz, Guadalupe; Gratton, Jean Philippe; Côté, Jean-François; Vázquez-Prado, José

    2017-07-21

    Developmental angiogenesis and the maintenance of the blood-brain barrier involve endothelial cell adhesion, which is linked to cytoskeletal dynamics. GPR124 (also known as TEM5/ADGRA2) is an adhesion G protein-coupled receptor family member that plays a pivotal role in brain angiogenesis and in ensuring a tight blood-brain barrier. However, the signaling properties of GPR124 remain poorly defined. Here, we show that ectopic expression of GPR124 promotes cell adhesion, additive to extracellular matrix-dependent effect, coupled with filopodia and lamellipodia formation and an enrichment of a pool of the G protein-coupled receptor at actin-rich cellular protrusions containing VASP, a filopodial marker. Accordingly, GPR124-expressing cells also displayed increased activation of both Rac and Cdc42 GTPases. Mechanistically, we uncover novel direct interactions between endogenous GPR124 and the Rho guanine nucleotide exchange factors Elmo/Dock and intersectin (ITSN). Small fragments of either Elmo or ITSN1 that bind GPR124 blocked GPR124-induced cell adhesion. In addition, Gβγ interacts with the C-terminal tail of GPR124 and promotes the formation of a GPR124-Elmo complex. Furthermore, GPR124 also promotes the activation of the Elmo-Dock complex, as measured by Elmo phosphorylation on a conserved C-terminal tyrosine residue. Interestingly, Elmo and ITSN1 also interact with each other independently of their GPR124-recognition regions. Moreover, endogenous phospho-Elmo and ITSN1 co-localize with GPR124 at lamellipodia of adhering endothelial cells, where GPR124 expression contributes to polarity acquisition during wound healing. Collectively, our results indicate that GPR124 promotes cell adhesion via Elmo-Dock and ITSN. This constitutes a previously unrecognized complex formed of atypical and conventional Rho guanine nucleotide exchange factors for Rac and Cdc42 that is putatively involved in GPR124-dependent angiogenic responses. © 2017 by The American Society for

  11. Visual Sensory Signals Dominate Tactile Cues during Docked Feeding in Hummingbirds.

    Science.gov (United States)

    Goller, Benjamin; Segre, Paolo S; Middleton, Kevin M; Dickinson, Michael H; Altshuler, Douglas L

    2017-01-01

    Animals living in and interacting with natural environments must monitor and respond to changing conditions and unpredictable situations. Using information from multiple sensory systems allows them to modify their behavior in response to their dynamic environment but also creates the challenge of integrating different, and potentially contradictory, sources of information for behavior control. Understanding how multiple information streams are integrated to produce flexible and reliable behavior is key to understanding how behavior is controlled in natural settings. Natural settings are rarely still, which challenges animals that require precise body position control, like hummingbirds, which hover while feeding from flowers. Tactile feedback, available only once the hummingbird is docked at the flower, could provide additional information to help maintain its position at the flower. To investigate the role of tactile information for hovering control during feeding, we first asked whether hummingbirds physically interact with a feeder once docked. We quantified physical interactions between docked hummingbirds and a feeder placed in front of a stationary background pattern. Force sensors on the feeder measured a complex time course of loading that reflects the wingbeat frequency and bill movement of feeding hummingbirds, and suggests that they sometimes push against the feeder with their bill. Next, we asked whether the measured tactile interactions were used by feeding hummingbirds to maintain position relative to the feeder. We created two experimental scenarios-one in which the feeder was stationary and the visual background moved and the other where the feeder moved laterally in front of a white background. When the visual background pattern moved, docked hummingbirds pushed significantly harder in the direction of horizontal visual motion. When the feeder moved, and the background was stationary, hummingbirds generated aerodynamic force in the opposite

  12. Electro-Pneumatic Control System with Hydraulically Positioning Actuator Motor

    Directory of Open Access Journals (Sweden)

    V. N. Pilgunov

    2016-01-01

    Full Text Available A compressibility of the actuating fluid of a pneumatic drive (compressed air leads to significant landing of the pneumatic cylinder piston at the time of stop and hold of the load, a constant component of which can fluctuate significantly for the holding period.There are a lot of factors, which have a significant impact on the landing value of piston. Those are: an initial position of the piston at its stop, which determines the volume of the an active area of the piston, a value of the constant load component at the time of stop and its variation for the holding period, a transfer coefficient of the position component of the load, an active area of the pneumatic cylinder piston, as well as reduction in atmospheric pressure, which can significantly affect the operation of the control systems of small aircrafts flying at high altitudes.To reduce the landing value of piston due to changing value of the constant load component for its holding period, it is proposed to use a hydraulic positioner, which comprises a hydraulic cylinder the rod of which is rigidly connected to the rod of the pneumatic cylinder through the traverse, a cross-feed valve of the hydro-cylinder cavities with discrete electro-magnetic control, and adjustable chokes.A programmable logic controller provides the hydraulic positioner control. At the moment the piston stops and the load is held the cross-feed valve overlaps the hydro-cylinder cavities thereby locking the pneumatic cylinder piston and preventing its landing. With available pneumatic cylinder-controlled signal the cross-feed valve connects the piston and rod cavities of the positioner hydro-cylinder, the pneumatic cylinder piston is released and becomes capable of moving.A numerical estimate of landing of the pneumatic cylinder piston and its positioning quality is of essential interest. For this purpose, a technique to calculate the landing of piston has been developed taking into consideration that different

  13. MDEP Common Position No EPR-01 - Common positions on the EPR instrumentation and controls design

    International Nuclear Information System (INIS)

    2010-01-01

    The purpose of the EPR Working Group (EPRWG) of the Multinational Design Evaluation Program (MDEP) is to identify common positions among the regulators reviewing the EPR Instrumentation and Controls (I and C) Systems in order to: 1. Promote understanding of each country 's regulatory decisions and basis for the decisions, 2. Enhance communication among the members and with external stakeholders, 3. Identify areas where harmonization and convergence of regulations, standards, and guidance can be achieved or improved, and 4. Supports standardization of new reactor designs. Since January 2008, the EPR I and C Technical Expert Subgroup (TESG) members met five times to exchange information regarding their country 's review of the EPR I and C design. The EPR I and C TESG consists of regulators from China, Canada, Finland, France, the United Kingdom, and the United States. The information exchange includes presentation of each country 's review status and technical issues, sharing of guidance documents, and sharing of regulatory decision documents. The TESG focused on the following four core areas of the EPR I and C design: 1. I and C System Independence (particularly for data communications), 2. Level of Defense and Diversity (back-up systems), 3. Qualification/quality of digital platforms, 4. Categorization/classification of systems and functions. As meetings were conducted, some areas were emphasized more depending on the significance of the issues for each country. During the TESG interactions, it became apparent that there were aspects of the EPR design where the countries had common agreement. On November 2, 2009, three of the subgroup countries, France, Finland and the United Kingdom, issued a joint regulatory position on the EPR I and C design as result of the 'Groupe Permanent' meeting in France. This statement of common positions expands upon that joint regulatory position

  14. New generation of docking programs: Supercomputer validation of force fields and quantum-chemical methods for docking.

    Science.gov (United States)

    Sulimov, Alexey V; Kutov, Danil C; Katkova, Ekaterina V; Ilin, Ivan S; Sulimov, Vladimir B

    2017-11-01

    Discovery of new inhibitors of the protein associated with a given disease is the initial and most important stage of the whole process of the rational development of new pharmaceutical substances. New inhibitors block the active site of the target protein and the disease is cured. Computer-aided molecular modeling can considerably increase effectiveness of new inhibitors development. Reliable predictions of the target protein inhibition by a small molecule, ligand, is defined by the accuracy of docking programs. Such programs position a ligand in the target protein and estimate the protein-ligand binding energy. Positioning accuracy of modern docking programs is satisfactory. However, the accuracy of binding energy calculations is too low to predict good inhibitors. For effective application of docking programs to new inhibitors development the accuracy of binding energy calculations should be higher than 1kcal/mol. Reasons of limited accuracy of modern docking programs are discussed. One of the most important aspects limiting this accuracy is imperfection of protein-ligand energy calculations. Results of supercomputer validation of several force fields and quantum-chemical methods for docking are presented. The validation was performed by quasi-docking as follows. First, the low energy minima spectra of 16 protein-ligand complexes were found by exhaustive minima search in the MMFF94 force field. Second, energies of the lowest 8192 minima are recalculated with CHARMM force field and PM6-D3H4X and PM7 quantum-chemical methods for each complex. The analysis of minima energies reveals the docking positioning accuracies of the PM7 and PM6-D3H4X quantum-chemical methods and the CHARMM force field are close to one another and they are better than the positioning accuracy of the MMFF94 force field. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Position Control of an X4-Flyer Using a Tether

    Directory of Open Access Journals (Sweden)

    Yusuke Ouchi

    2016-05-01

    Full Text Available In Japan, aging of infrastructures, such as roads,bridges, and water and sewer services, etc. poses a problem, andit is required to extend the life-span of such infrastructures bymaintenance. Among infrastructures, especially bridges areperiodically inspected by short range visual observations, whichcheck the damage and deterioration of the surface. However,since there are some cases where the short range visualobservation is difficult, an alternative method is required so as toreplace the short range visual observation with it. So, "X4-Flyer"is very attractive because of realizing a movement at high altitudeeasily. The objective of this study is to develop a tethered X4-Flyer, so that the conventional short range visual observation ofbridges is replaced by it. In this paper, a method for themeasurement and control of the position is described by using atether for controlling the position of the X4-Flyer. In addition, itis checked whether the tethered X4-Flyer can control the positionusing the proposed method or not, letting it fly in a state in whicha tether is being attached

  16. Robust control design for the plasma horizontal position control on J-TEXT Tokamak

    International Nuclear Information System (INIS)

    Yu, W.Z.; Chen, Z.P.; Zhuang, G.; Wang, Z.J.

    2013-01-01

    It is extremely important for tokamak to control the plasma position during routine discharge. However, the model of plasma in tokamak usually contains much of the uncertainty, such as structured uncertainties and unmodeled dynamics. Compared with the traditional PID control approach, robust control theory is more suitable to handle this problem. In the paper, we propose a H ∞ robust control scheme to control the horizontal position of plasma during the flat-top phase of discharge on Joint Texas Experimental Tokamak (J-TEXT) tokamak. First, the model of our plant for plasma horizontal position control is obtained from the position equilibrium equations. Then the H ∞ robust control framework is used to synthesize the controller. Based on this, an H ∞ controller is designed to minimize the regulation/tracking error. Finally, a comparison study is conducted between the optimized H ∞ robust controller and the traditional PID controller in simulations. The simulation results of the H ∞ robust controller show a significant improvement of the performance with respect to those obtained with traditional PID controller, which is currently used on our machine

  17. Controlled positioning of nanoparticles on graphene by noninvasive AFM lithography.

    Science.gov (United States)

    Bellido, Elena; Ojea-Jiménez, Isaac; Ghirri, Alberto; Alvino, Christian; Candini, Andrea; Puntes, Victor; Affronte, Marco; Domingo, Neus; Ruiz-Molina, Daniel

    2012-08-21

    Atomic force microscopy is shown to be an excellent lithographic technique to directly deposit nanoparticles on graphene by capillary transport without any previous functionalization of neither the nanoparticles nor the graphene surface while preserving its integrity and conductivity properties. Moreover this technique allows for (sub)micrometric control on the positioning thanks to a new three-step protocol that has been designed with this aim. With this methodology the exact target coordinates are registered by scanning the tip over the predetermined area previous to its coating with the ink and deposition. As a proof-of-concept, this strategy has successfully allowed the controlled deposition of few nanoparticles on 1 μm(2) preselected sites of a graphene surface with high accuracy.

  18. Quality control in diagnostic immunohistochemistry: integrated on-slide positive controls.

    Science.gov (United States)

    Bragoni, A; Gambella, A; Pigozzi, S; Grigolini, M; Fiocca, R; Mastracci, L; Grillo, F

    2017-11-01

    Standardization in immunohistochemistry is a priority in modern pathology and requires strict quality control. Cost containment has also become fundamental and auditing of all procedures must take into account both these principles. Positive controls must be routinely performed so that their positivity guarantees the appropriateness of the immunohistochemical procedure. The aim of this study is to develop a low cost (utilizing a punch biopsy-PB-tool) procedure to construct positive controls which can be integrated in the patient's tissue slide. Sixteen frequently used control blocks were selected and multiple cylindrical samples were obtained using a 5-mm diameter punch biopsy tool, separately re-embedding them in single blocks. For each diagnostic immunoreaction requiring a positive control, an integrated PB-control section (cut from the appropriate PB-control block) was added to the top right corner of the diagnostic slide before immunostaining. This integrated control technique permitted a saving of 4.75% in total direct lab costs and proved to be technically feasible and reliable. Our proposal is easy to perform and within the reach of all pathology labs, requires easily available tools, its application costs is less than using external paired controls and ensures that a specific control for each slide is always available.

  19. Review of design technology of control rod position indicators

    International Nuclear Information System (INIS)

    Yu, Je Yong; Huh, Hyung; Kim, Ji Ho; Kim, Jong In; Chang, Moon Hee

    1999-10-01

    An integral reactor SMART is under development at KAERI. The design characteristics of SMART are radically different from those employer in currently operating loop type water reactors in Korea. The objective of this report is to review the design technology of position indicator, and to study the various sensors which can be used in rod position indicator. Design criteria that rod position indicator should satisfy are also examined. Following position indicators are reviewed in this report. 1. Digital positioning indicator (DRPI), 2. Reed switch type position indicator (RSPT), 3. Choke sensor type position indicator, 4. Ultrasonic sensor type position indicator, 5. Comparison of each position indicator. (author)

  20. Position control of a floating nuclear power plant

    International Nuclear Information System (INIS)

    Motohashi, K.; Hamamoto, T.; Sasaki, R.; Kojima, M.

    1993-01-01

    In spite of the increasing demand of electricity in Japan, the sites of nuclear power plants suitable for conventional seismic regulations become severely limited. Under these circumstances, several types of advanced siting technology have been developed. Among them, floating power plants have a great advantage of seismic isolation that leads to the seismic design standardization and factory fabrication. The feasibility studies or preliminary designs of floating power plants enclosed by breakwaters in the shallow sea have been carried out last two decades in U.S. and Japan. On the other hand, there are few investigations on the dynamic behavior of floating power plants in the deep sea. The offshore floating nuclear power plants have an additional advantage in that large breakwaters are not required, although the safety checking is inevitable against wind-induced waves. The tension-leg platforms which have been constructed for oil drilling in the deep sea seem to be a promising offshore siting technology of nuclear power plants. The tension-leg mooring system can considerably restrain the heave and pitch of a floating power plant because of significant stiffness in the vertical direction. Different from seismic effects, wind-induced waves may be predicted in advance by making use of ocean weather forecasts using artificial satellites. According to the wave prediction, the position of the floating plant may be controlled by adjusting the water content in ballast tanks and the length of tension-legs before the expected load arrives. The position control system can reduce the wave force acting on the plant and to avoid the unfavorable response behavior of the plant. In this study a semi-submerged circular cylinder with tension-legs is considered as a mathematical model. The configuration of circular cylinder is effective because the dynamic behavior does not depend on incident wave directions. It is also unique in that it can obtain the closed-form solution of

  1. Dry dock gate stability modelling

    Science.gov (United States)

    Oktoberty; Widiyanto; Sasono, E. J.; Pramono, S.; Wandono, A. T.

    2018-03-01

    The development of marine transportation needs in Indonesia increasingly opens national shipyard business opportunities to provide shipbuilding services to the shipbuilding vessels. That emphasizes the stability of prime. The ship's decking door becomes an integral part of the efficient place and the specification of the use of the asset of its operational ease. This study aims to test the stability of Dry Dock gate with the length of 35.4 meters using Maxsurf and Hydromax in analyzing the calculation were in its assessment using interval per 500 mm length so that it can get detail data toward longitudinal and transverse such as studying Ship planning in general. The test result shows dry dock gate meets IMO standard with ballast construction containing 54% and 68% and using fix ballast can produce GMt 1,924 m, tide height 11,357m. The GMt value indicates dry dick gate can be stable and firmly erect at the base of the mouth dry dock. When empty ballast produces GMt 0.996 which means dry dock date is stable, but can easily be torn down. The condition can be used during dry dock gate treatment.

  2. Fault Tolerant Position-mooring Control for Offshore Vessels

    DEFF Research Database (Denmark)

    Blanke, Mogens; Nguyen, Trong Dong

    2018-01-01

    Fault-tolerance is crucial to maintain safety in offshore operations. The objective of this paper is to show how systematic analysis and design of fault-tolerance is conducted for a complex automation system, exemplified by thruster assisted Position-mooring. Using redundancy as required....... Functional faults that are only detectable, are rendered isolable through an active isolation approach. Once functional faults are isolated, they are handled by fault accommodation techniques to meet overall control objectives specified by class requirements. The paper illustrates the generic methodology...... by a system to handle faults in mooring lines, sensors or thrusters. Simulations and model basin experiments are carried out to validate the concept for scenarios with single or multiple faults. The results demonstrate that enhanced availability and safety are obtainable with this design approach. While...

  3. Asymmetric positive feedback loops reliably control biological responses.

    Science.gov (United States)

    Ratushny, Alexander V; Saleem, Ramsey A; Sitko, Katherine; Ramsey, Stephen A; Aitchison, John D

    2012-04-24

    Positive feedback is a common mechanism enabling biological systems to respond to stimuli in a switch-like manner. Such systems are often characterized by the requisite formation of a heterodimer where only one of the pair is subject to feedback. This ASymmetric Self-UpREgulation (ASSURE) motif is central to many biological systems, including cholesterol homeostasis (LXRα/RXRα), adipocyte differentiation (PPARγ/RXRα), development and differentiation (RAR/RXR), myogenesis (MyoD/E12) and cellular antiviral defense (IRF3/IRF7). To understand why this motif is so prevalent, we examined its properties in an evolutionarily conserved transcriptional regulatory network in yeast (Oaf1p/Pip2p). We demonstrate that the asymmetry in positive feedback confers a competitive advantage and allows the system to robustly increase its responsiveness while precisely tuning the response to a consistent level in the presence of varying stimuli. This study reveals evolutionary advantages for the ASSURE motif, and mechanisms for control, that are relevant to pharmacologic intervention and synthetic biology applications.

  4. Vertical position control of the elongated INTOR plasma

    International Nuclear Information System (INIS)

    Ueda, Kojyu; Nishio, Satoshi; Fujisawa, Noboru; Sugihara, Masayoshi; Saito, Seiji; Miyamoto, Kenro.

    1983-01-01

    A newly devised rectangular shell, which has the sufficient shell effect for the stabilization of the fast mode, is presented, along with the studies of various kinds of shell-structures described on this paper. It can be expected that the rectangular shells have negligibly small effect on the breeding ratio by locating them separately on both of the front and rear surfaces of blanket. Some properties with the modelled feedback control system are elucidated under a disturbance field, B sub(d) = B sub(infinity).[1-exp(-t/tau sub(d))] (B sub(infinity): field strength at t = infinity, tau sub(d): time constant). They are studied for two kinds of decay indices, that is, -1.0 for the pump limiter and -1.3 for the divertor. Conclusively, the control system is found to have good characteristics. The PID controller seems to provide the stable control of vertical position better than the PI controller. The maximum of vertical displacement, Z sub(p)sup(max) under the disturbance field, B sub(d), are in proportion to B sub(infinity). The power required for its stabilization, P, are also in proportion to B sub(infinity)sup(2), and then to (Z sub(P)sup(MAX))sup(2), too. Therefore, some common basis for B sub(infinity) or Z sub(P)sup(MAX) is required for its estimation. Moreover, the power is found to be independent of selection of the PI or PID controller, and to have approximately the same relation with Z sub(P)sup(MAX). The difference of P between -1.0 and -1.3 in the decay index is very large when Z sub(P)sup(MAX) is more than -1.0 cm. For example, in the vicinity of Z sub(P)sup(MAX) = 1.0 cm, the power in the case of n = -1.0 is about one half of that in the case of n = -1.3. But it decreases abruptly when Z sub(P)sup(MAX) is less than 0.5 cm. (J.P.N.)

  5. A python-based docking program utilizing a receptor bound ligand shape: PythDock.

    Science.gov (United States)

    Chung, Jae Yoon; Cho, Seung Joo; Hah, Jung-Mi

    2011-09-01

    PythDock is a heuristic docking program that uses Python programming language with a simple scoring function and a population based search engine. The scoring function considers electrostatic and dispersion/repulsion terms. The search engine utilizes a particle swarm optimization algorithm. A grid potential map is generated using the shape information of a bound ligand within the active site. Therefore, the searching area is more relevant to the ligand binding. To evaluate the docking performance of PythDock, two well-known docking programs (AutoDock and DOCK) were also used with the same data. The accuracy of docked results were measured by the difference of the ligand structure between x-ray structure, and docked pose, i.e., average root mean squared deviation values of the bound ligand were compared for fourteen protein-ligand complexes. Since the number of ligands' rotational flexibility is an important factor affecting the accuracy of a docking, the data set was chosen to have various degrees of flexibility. Although PythDock has a scoring function simpler than those of other programs (AutoDock and DOCK), our results showed that PythDock predicted more accurate poses than both AutoDock4.2 and DOCK6.2. This indicates that PythDock could be a useful tool to study ligand-receptor interactions and could also be beneficial in structure based drug design.

  6. VelC positively controls sexual development in Aspergillus nidulans.

    Directory of Open Access Journals (Sweden)

    Hee-Soo Park

    Full Text Available Fungal development and secondary metabolism is intimately associated via activities of the fungi-specific velvet family proteins including VeA, VosA, VelB and VelC. Among these, VelC has not been characterized in Aspergillus nidulans. In this study, we characterize the role of VelC in asexual and sexual development in A. nidulans. The velC mRNA specifically accumulates during the early phase of sexual development. The deletion of velC leads to increased number of conidia and reduced production of sexual fruiting bodies (cleistothecia. In the velC deletion mutant, mRNA levels of the brlA, abaA, wetA and vosA genes that control sequential activation of asexual sporulation increase. Overexpression of velC causes increased formation of cleistothecia. These results suggest that VelC functions as a positive regulator of sexual development. VelC is one of the five proteins that physically interact with VosA in yeast two-hybrid and GST pull down analyses. The ΔvelC ΔvosA double mutant produced fewer cleistothecia and behaved similar to the ΔvosA mutant, suggesting that VosA is epistatic to VelC in sexual development, and that VelC might mediate control of sex through interacting with VosA at specific life stages for sexual fruiting.

  7. The Human Eye Position Control System in a Rehabilitation Setting

    Directory of Open Access Journals (Sweden)

    Yvonne Nolan

    2005-01-01

    Full Text Available Our work at Ireland’s National Rehabilitation Hospital involves designing communication systems for people suffering from profound physical disabilities. One such system uses the electro-oculogram, which is an (x,y system of voltages picked up by pairs of electrodes placed, respectively, above and below and on either side of the eyes. The eyeball has a dc polarisation between cornea and back, arising from the photoreceptor rods and cones in the retina. As the eye rotates, the varying voltages projected onto the electrodes drive a cursor over a mimic keyboard on a computer screen. Symbols are selected with a switching action derived, for example, from a blink. Experience in using this mode of communication has given us limited facilities to study the eye position control system. We present here a resulting new feedback model for rotation in either the vertical or the horizontal plane, which involves the eyeball controlled by an agonist-antagonist muscle pair, modelled by a single equivalent bidirectional muscle with torque falling off linearly with angular velocity. We have incorporated muscle spindles and have tuned them by pole assignment associated with an optimum stability criterion.

  8. Position control of ECRH launcher mirrors by laser speckle sensor

    International Nuclear Information System (INIS)

    Michelsen, Poul K.; Bindslev, Henrik; Hansen, Rene Skov; Hanson, Steen G.

    2003-01-01

    The planned ECRH system for JET included several fixed and steerable mirrors some of which should have been fixed to the building structure and some to the JET vessel structure. A similar system may be anticipated for ITER and for other fusion devices in the future. In order to have high reproducibility of the ECRH beam direction, it is necessary to know the exact positions of the mirrors. This is not a trivial problem because of thermal expansion of the vessel structures and of the launcher itself and of its support structure, the mechanical load on mirrors and support structures, and the accessibility to the various mirrors. We suggest to use a combination of infrared diagnostic of beam spot positions and a new technique published recently, which is based on a non-contact laser speckle sensor for measuring one- and two-dimensional angular displacement. The method is based on Fourier transforming the scattered field from a single laser beam that illuminates the target. The angular distribution of the light field at the target is linearly mapped onto an array image sensor placed in the Fourier plane. Measuring the displacement of this so-called speckle pattern facilitates the determination of the mirror orientation. Transverse target movement can be measured by observing the speckle movement in the image plane of the object. No special surface treatment is required for surfaces having irregularities of the order of or larger than the wavelength of the incident light. For the JET ECRH launcher it is mainly for the last mirror pointing towards the plasma where the technique may be useful. This mirror has to be steerable in order to reflect the microwave beam in the correct direction towards the plasma. Maximum performance of the microwave heating requires that the beam hits this mirror at its centre and that the mirror is turned in the correct angle. Inaccuracies in the positioning of the pull rods for controlling the mirror turning and thermal effects makes it

  9. Single axis control of ball position in magnetic levitation system using fuzzy logic control

    Science.gov (United States)

    Sahoo, Narayan; Tripathy, Ashis; Sharma, Priyaranjan

    2018-03-01

    This paper presents the design and real time implementation of Fuzzy logic control(FLC) for the control of the position of a ferromagnetic ball by manipulating the current flowing in an electromagnet that changes the magnetic field acting on the ball. This system is highly nonlinear and open loop unstable. Many un-measurable disturbances are also acting on the system, making the control of it highly complex but interesting for any researcher in control system domain. First the system is modelled using the fundamental laws, which gives a nonlinear equation. The nonlinear model is then linearized at an operating point. Fuzzy logic controller is designed after studying the system in closed loop under PID control action. The controller is then implemented in real time using Simulink real time environment. The controller is tuned manually to get a stable and robust performance. The set point tracking performance of FLC and PID controllers were compared and analyzed.

  10. Text Mining for Protein Docking.

    Directory of Open Access Journals (Sweden)

    Varsha D Badal

    2015-12-01

    Full Text Available The rapidly growing amount of publicly available information from biomedical research is readily accessible on the Internet, providing a powerful resource for predictive biomolecular modeling. The accumulated data on experimentally determined structures transformed structure prediction of proteins and protein complexes. Instead of exploring the enormous search space, predictive tools can simply proceed to the solution based on similarity to the existing, previously determined structures. A similar major paradigm shift is emerging due to the rapidly expanding amount of information, other than experimentally determined structures, which still can be used as constraints in biomolecular structure prediction. Automated text mining has been widely used in recreating protein interaction networks, as well as in detecting small ligand binding sites on protein structures. Combining and expanding these two well-developed areas of research, we applied the text mining to structural modeling of protein-protein complexes (protein docking. Protein docking can be significantly improved when constraints on the docking mode are available. We developed a procedure that retrieves published abstracts on a specific protein-protein interaction and extracts information relevant to docking. The procedure was assessed on protein complexes from Dockground (http://dockground.compbio.ku.edu. The results show that correct information on binding residues can be extracted for about half of the complexes. The amount of irrelevant information was reduced by conceptual analysis of a subset of the retrieved abstracts, based on the bag-of-words (features approach. Support Vector Machine models were trained and validated on the subset. The remaining abstracts were filtered by the best-performing models, which decreased the irrelevant information for ~ 25% complexes in the dataset. The extracted constraints were incorporated in the docking protocol and tested on the Dockground unbound

  11. Position Control of a Pneumatic Muscle Actuator Using RBF Neural Network Tuned PID Controller

    Directory of Open Access Journals (Sweden)

    Jie Zhao

    2015-01-01

    Full Text Available Pneumatic Muscle Actuator (PMA has a broad application prospect in soft robotics. However, PMA has highly nonlinear and hysteretic properties among force, displacement, and pressure, which lead to difficulty in accurate position control. A phenomenological model is developed to portray the hysteretic behavior of PMA. This phenomenological model consists of linear component and hysteretic component force. The latter component is described by Duhem model. An experimental apparatus is built up and sets of experimental data are acquired. Based on the experimental data, parameters of the model are identified. Validation of the model is performed. Then a novel cascade position PID controller is devised for a 1-DOF manipulator actuated by PMA. The outer loop of the controller is to cope with position control whilst the inner loop deals with pressure dynamics within PMA. To enhance the adaptability of the PID algorithm to the high nonlinearities of the manipulator, PID parameters are tuned online using RBF Neural Network. Experiments are performed and comparison between position response of RBF Neural Network based PID controller and that of classic PID controller demonstrates the effectiveness of the novel adaptive controller on the manipulator.

  12. NASA Docking System (NDS) Technical Integration Meeting

    Science.gov (United States)

    Lewis, James L.

    2010-01-01

    This slide presentation reviews the NASA Docking System (NDS) as NASA's implementation of the International Docking System Standard (IDSS). The goals of the NDS, is to build on proven technologies previously demonstrated in flight and to advance the state of the art of docking systems by incorporating Low Impact Docking System (LIDS) technology into the NDS. A Hardware Demonstration was included in the meeting, and there was discussion about software, NDS major system interfaces, integration information, schedule, and future upgrades.

  13. Structure-activity relationships and molecular docking of thirteen synthesized flavonoids as horseradish peroxidase inhibitors.

    Science.gov (United States)

    Mahfoudi, Reguia; Djeridane, Amar; Benarous, Khedidja; Gaydou, Emile M; Yousfi, Mohamed

    2017-10-01

    For the first time, the structure-activity relationships of thirteen synthesized flavonoids have been investigated by evaluating their ability to modulate horseradish peroxidase (HRP) catalytic activity. Indeed, a modified spectrophotometrically method was carried out and optimized using 4-methylcatechol (4-MC) as peroxidase co-substrate. The results show that these flavonoids exhibit a great capacity to inhibit peroxidase with Ki values ranged from 0.14±0.01 to 65±0.04mM. Molecular docking has been achieved using Auto Dock Vina program to discuss the nature of interactions and the mechanism of inhibition. According to the docking results, all the flavonoids have shown great binding affinity to peroxidase. These molecular modeling studies suggested that pyran-4-one cycle acts as an inhibition key for peroxidase. Therefore, potent peroxidase inhibitors are flavonoids with these structural requirements: the presence of the hydroxyl (OH) group in 7, 5 and 4' positions and the absence of the methoxy (O-CH 3 ) group. Apigenin contributed better in HRP inhibitory activity. The present study has shown that the studied flavonoids could be promising HRP inhibitors, which can help in developing new molecules to control thyroid diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Positive and negative peptide signals control stomatal density.

    Science.gov (United States)

    Shimada, Tomoo; Sugano, Shigeo S; Hara-Nishimura, Ikuko

    2011-06-01

    The stoma is a micro valve found on aerial plant organs that promotes gas exchange between the atmosphere and the plant body. Each stoma is formed by a strict cell lineage during the early stages of leaf development. Molecular genetics research using the model plant Arabidopsis has revealed the genes involved in stomatal differentiation. Cysteine-rich secretory peptides of the EPIDERMAL PATTERNING FACTOR-LIKE (EPFL) family play crucial roles as extracellular signaling factors. Stomatal development is orchestrated by the positive factor STOMAGEN/EPFL9 and the negative factors EPF1, EPF2, and CHALLAH/EPFL6 in combination with multiple receptors. EPF1 and EPF2 are produced in the stomatal lineage cells of the epidermis, whereas STOMAGEN and CHALLAH are derived from the inner tissues. These findings highlight the complex cell-to-cell and intertissue communications that regulate stomatal development. To optimize gas exchange, particularly the balance between the uptake of carbon dioxide (CO(2)) and loss of water, plants control stomatal activity in response to environmental conditions. The CO(2) level and light intensity influence stomatal density. Plants sense environmental cues in mature leaves and adjust the stomatal density of newly forming leaves, indicating the involvement of long-distance systemic signaling. This review summarizes recent research progress in the peptide signaling of stomatal development and discusses the evolutionary model of the signaling machinery.

  15. Molecular Dynamics and Docking of Biphenyl: A Potential ...

    African Journals Online (AJOL)

    Purpose: To develop a new drug that inhibits viral attachment and entry for the treatment of HIV/AIDS patients. Methods: Two Protein Databank (PDB) crystal structures of HIV-1 gp120-CD4 complexes, namely, 1RZK and 1G9N, were mutated at amino acid position 43 to a biphenylalanine (biPhe-43) residue. FireDock web ...

  16. ARCADE small-scale docking mechanism for micro-satellites

    Science.gov (United States)

    Boesso, A.; Francesconi, A.

    2013-05-01

    The development of on-orbit autonomous rendezvous and docking (ARD) capabilities represents a key point for a number of appealing mission scenarios that include activities of on-orbit servicing, automated assembly of modular structures and active debris removal. As of today, especially in the field of micro-satellites ARD, many fundamental technologies are still missing or require further developments and micro-gravity testing. In this framework, the University of Padova, Centre of Studies and Activities for Space (CISAS), developed the Autonomous Rendezvous Control and Docking Experiment (ARCADE), a technology demonstrator intended to fly aboard a BEXUS stratospheric balloon. The goal was to design, build and test, in critical environment conditions, a proximity relative navigation system, a custom-made reaction wheel and a small-size docking mechanism. The ARCADE docking mechanism was designed against a comprehensive set of requirements and it can be classified as small-scale, central, gender mating and unpressurized. The large use of commercial components makes it low-cost and simple to be manufactured. Last, it features a good tolerance to off-nominal docking conditions and a by-design soft docking capability. The final design was extensively verified to be compliant with its requirements by means of numerical simulations and physical testing. In detail, the dynamic behaviour of the mechanism in both nominal and off-nominal conditions was assessed with the multibody dynamics analysis software MD ADAMS 2010 and functional tests were carried out within the fully integrated ARCADE experiment to ensure the docking system efficacy and to highlight possible issues. The most relevant results of the study will be presented and discussed in conclusion to this paper.

  17. Protein-protein docking with dynamic residue protonation states.

    Directory of Open Access Journals (Sweden)

    Krishna Praneeth Kilambi

    2014-12-01

    Full Text Available Protein-protein interactions depend on a host of environmental factors. Local pH conditions influence the interactions through the protonation states of the ionizable residues that can change upon binding. In this work, we present a pH-sensitive docking approach, pHDock, that can sample side-chain protonation states of five ionizable residues (Asp, Glu, His, Tyr, Lys on-the-fly during the docking simulation. pHDock produces successful local docking funnels in approximately half (79/161 the protein complexes, including 19 cases where standard RosettaDock fails. pHDock also performs better than the two control cases comprising docking at pH 7.0 or using fixed, predetermined protonation states. On average, the top-ranked pHDock structures have lower interface RMSDs and recover more native interface residue-residue contacts and hydrogen bonds compared to RosettaDock. Addition of backbone flexibility using a computationally-generated conformational ensemble further improves native contact and hydrogen bond recovery in the top-ranked structures. Although pHDock is designed to improve docking, it also successfully predicts a large pH-dependent binding affinity change in the Fc-FcRn complex, suggesting that it can be exploited to improve affinity predictions. The approaches in the study contribute to the goal of structural simulations of whole-cell protein-protein interactions including all the environmental factors, and they can be further expanded for pH-sensitive protein design.

  18. Linear quadratic Gaussian controller design for plasma current, position and shape control system in ITER

    International Nuclear Information System (INIS)

    Belyakov, V.; Kavin, A.; Rumyantsev, E.; Kharitonov, V.; Misenov, B.; Ovsyannikov, A.; Ovsyannikov, D.; Veremei, E.; Zhabko, A.; Mitrishkin, Y.

    1999-01-01

    This paper is focused on the linear quadratic Gaussian (LQG) controller synthesis methodology for the ITER plasma current, position and shape control system as well as power derivative management system. It has been shown that some poloidal field (PF) coils have less influence on reference plasma-wall gaps control during plasma disturbances and hence they have been used to reduce total control power derivative by means of the additional non-linear feedback. The design has been done on the basis of linear models. Simulation was provided for non-linear model and results are presented and discussed. (orig.)

  19. DARC 2.0: Improved Docking and Virtual Screening at Protein Interaction Sites.

    Directory of Open Access Journals (Sweden)

    Ragul Gowthaman

    Full Text Available Over the past decade, protein-protein interactions have emerged as attractive but challenging targets for therapeutic intervention using small molecules. Due to the relatively flat surfaces that typify protein interaction sites, modern virtual screening tools developed for optimal performance against "traditional" protein targets perform less well when applied instead at protein interaction sites. Previously, we described a docking method specifically catered to the shallow binding modes characteristic of small-molecule inhibitors of protein interaction sites. This method, called DARC (Docking Approach using Ray Casting, operates by comparing the topography of the protein surface when "viewed" from a vantage point inside the protein against the topography of a bound ligand when "viewed" from the same vantage point. Here, we present five key enhancements to DARC. First, we use multiple vantage points to more accurately determine protein-ligand surface complementarity. Second, we describe a new scheme for rapidly determining optimal weights in the DARC scoring function. Third, we incorporate sampling of ligand conformers "on-the-fly" during docking. Fourth, we move beyond simple shape complementarity and introduce a term in the scoring function to capture electrostatic complementarity. Finally, we adjust the control flow in our GPU implementation of DARC to achieve greater speedup of these calculations. At each step of this study, we evaluate the performance of DARC in a "pose recapitulation" experiment: predicting the binding mode of 25 inhibitors each solved in complex with its distinct target protein (a protein interaction site. Whereas the previous version of DARC docked only one of these inhibitors to within 2 Å RMSD of its position in the crystal structure, the newer version achieves this level of accuracy for 12 of the 25 complexes, corresponding to a statistically significant performance improvement (p < 0.001. Collectively then, we find

  20. FPGA based Fuzzy Logic Controller for plasma position control in ADITYA Tokamak

    International Nuclear Information System (INIS)

    Suratia, Pooja; Patel, Jigneshkumar; Rajpal, Rachana; Kotia, Sorum; Govindarajan, J.

    2012-01-01

    Highlights: ► Evaluation and comparison of the working performance of FLC is done with that of PID Controller. ► FLC is designed using MATLAB Fuzzy Logic Toolbox, and validated on ADITYA RZIP model. ► FLC was implemented on a FPGA. The close-loop testing is done by interfacing FPGA to MATLAB/Simulink. ► Developed FLC controller is able to maintain the plasma column within required range of ±0.05 m and was found to give robust control against various disturbances and faster and smoother response compared to PID Controller. - Abstract: Tokamaks are the most promising devices for obtaining nuclear fusion energy from high-temperature, ionized gas termed as Plasma. The successful operation of tokamak depends on its ability to confine plasma at the geometric center of vacuum vessel with sufficient stability. The quality of plasma discharge in ADITYA Tokamak is strongly related to the radial position of the plasma column in the vacuum vessel. If the plasma column approaches too near to the wall of vacuum vessel, it leads to minor or complete disruption of plasma. Hence the control of plasma position throughout the entire plasma discharge duration is a fundamental requirement. This paper describes Fuzzy Logic Controller (FLC) which is designed for radial plasma position control. This controller is tested and evaluated on the ADITYA RZIP control model. The performance of this FLC was compared with that of Proportional–Integral–Derivative (PID) Controller and the response was found to be faster and smoother. FLC was implemented on a Field Programmable Gate Array (FPGA) chip with the use of a Very High-Speed Integrated-Circuits Hardware Description-Language (VHDL).

  1. Development of Vision Control Scheme of Extended Kalman filtering for Robot's Position Control

    International Nuclear Information System (INIS)

    Jang, W. S.; Kim, K. S.; Park, S. I.; Kim, K. Y.

    2003-01-01

    It is very important to reduce the computational time in estimating the parameters of vision control algorithm for robot's position control in real time. Unfortunately, the batch estimation commonly used requires too murk computational time because it is iteration method. So, the batch estimation has difficulty for robot's position control in real time. On the other hand, the Extended Kalman Filtering(EKF) has many advantages to calculate the parameters of vision system in that it is a simple and efficient recursive procedures. Thus, this study is to develop the EKF algorithm for the robot's vision control in real time. The vision system model used in this study involves six parameters to account for the inner(orientation, focal length etc) and outer (the relative location between robot and camera) parameters of camera. Then, EKF has been first applied to estimate these parameters, and then with these estimated parameters, also to estimate the robot's joint angles used for robot's operation. finally, the practicality of vision control scheme based on the EKF has been experimentally verified by performing the robot's position control

  2. Development of EPICS based beam-line experimental control employing motor controller for precision positioning

    International Nuclear Information System (INIS)

    Tuli, Anupriya; Jain, Rajiv; Vora, H.S.

    2015-01-01

    In a Synchrotron Radiation Source the beamline experiments are carried out in radiation prone environment, inside the hutch, which demands to conduct experiments remotely. These experiments involves instrument control and data acquisition from various devices. Another factor which attributes to system complexity is precise positioning of sample and placement of detectors. A large number of stepper motors are engaged for achieving the required precision positioning. This work is a result of development of Experimental Physics and Industrial Control System (EPICS) based control system to interface a stepper motor controller developed indigenously by Laser Electronics Support Division of RRCAT. EPICS is an internationally accepted open source software environment which follows toolkit approach and standard model paradigm. The operator interface for the control system software was implemented using CSS BOY. The system was successfully tested for Ethernet based remote access. The developed control software comprises of an OPI and alarm handler (EPICS ALH). Both OPI and ALH are linked with PV's defined in database files. The development process resulted into a set of EPICS based commands for controlling stepper motor. These commands are independent of operator interface, i.e. stepper motor can be controlled by using these set of commands directly on EPICS prompt. This command set is illustrated in the above table. EPICS Alarm Handler was also tested independently by running these commands on EPIC prompt. If not using ALH, operator can read the alarm status of a PV using 'SEVR' and 'STAT' attributes. (author)

  3. Behaviour of tail-docked lambs tested in isolation

    Directory of Open Access Journals (Sweden)

    Marchewka Joanna

    2016-12-01

    Full Text Available The aims of the current study were to detect behavioural indicators of pain of tail-docked sheep tested in isolation and to determine the relationship between behaviour and the pain levels to which they were exposed. Twenty-four female lambs, randomly assigned to four pens, had their tail docked with a rubber ring (TD; n = 6 without pain control procedures, TD with anaesthesia (TDA; n = 6 or TD with anaesthesia and analgesia (TDAA; n = 6. Additionally, six lambs handled but without tail docking or application of pain relief measures were used as the control (C. On the day prior (Day –1 to the TD and on days 1, 3 and 5 post-procedure, each lamb was individually removed from its group and underwent a 2.5 min open field test in a separate pen. Frequencies of behaviours such as rest, running, standing, walking and exploring were directly observed. Frequencies of exploratory climbs (ECs and abrupt climbs (ACs over the testing pen’s walls were video-recorded. Data were analysed using generalised linear mixed models with repeated measurements, including treatment and day as fixed effects and behaviour on Day –1 as a linear covariate. Control and TDAA lambs stood more frequently than TD lambs. TD lambs performed significantly more ACs compared to all other treatment groups. No other treatment effects were detected. A day effect was detected for all behaviours, while the EC frequency was highest for all tail-docked lambs on Day 5. Findings suggest that standing, ACs and ECs could be used as potential indicators of pain in isolated tail-docked lambs. However, differences in ECs between treatments only appeared 3 d after tail docking.

  4. Fault Monitoring and Fault Recovery Control for Position Moored Tanker

    DEFF Research Database (Denmark)

    Fang, Shaoji; Blanke, Mogens

    2011-01-01

    . In addition to dedicated diagnosis, an optimal position algorithm is proposed to accommodate buoyancy element failure and keep the mooring system in a safe state. Furthermore, even in the case of line breakage, this optimal position strategy could be utilised to avoid breakage of a second mooring line...

  5. Irradiation position-control equipment for the HIMAC

    Energy Technology Data Exchange (ETDEWEB)

    Higashi, Seiichi; Kuma, Shoichiro [Mitsubishi Electric Corp., Tokyo (Japan); Nomura, Kazuaki; Endo, Masahiro; Minohara, Shin-ichi

    1995-02-01

    Use of heavy-ion beams to mount a pinpoint attack on unhealthy tissue requires that the target tissue be placed in the precise location specified by the therapy planning equipment. The article reports on the detailed specifications, positioning mechanism, position verification method and the interface with the therapy planning equipment. (author).

  6. Verification of Positional Accuracy of ZVS3003 Geodetic Control ...

    African Journals Online (AJOL)

    The International GPS Service (IGS) has provided GPS orbit products to the scientific community with increased precision and timeliness. Many users interested in geodetic positioning have adopted the IGS precise orbits to achieve centimeter level accuracy and ensure long-term reference frame stability. Positioning with ...

  7. Adaptive Positive Position Feedback Control of Flexible Aircraft Structures Using Piezoelectric Actuators

    Science.gov (United States)

    2014-03-27

    need for adaptive control of BIVs. Adaptive control methods have been used in aerospace applications of many years, from flight controls [20] to cabin ... stress in the separated boundary layer causes larger values of the recirculating velocity, thus leading to a more unstable flow” [26]. In essence, as...Air Academy High School in Colorado Springs, Colorado. He attended the University of Colorado, Colorado Springs while completing a four year Reserve

  8. Robust Design of Docking Hoop for Recovery of Autonomous Underwater Vehicle with Experimental Results

    Directory of Open Access Journals (Sweden)

    Wei Peng Lin

    2015-12-01

    Full Text Available Control systems prototyping is usually constrained by model complexity, embedded system configurations, and interface testing. The proposed control system prototyping of a remotely-operated vehicle (ROV with a docking hoop (DH to recover an autonomous underwater vehicle (AUV named AUVDH using a combination of software tools allows the prototyping process to be unified. This process provides systematic design from mechanical, hydrodynamics, dynamics modelling, control system design, and simulation to testing in water. As shown in a three-dimensional simulation of an AUVDH model using MATLAB™/Simulink™ during the launch and recovery process, the control simulation of a sliding mode controller is able to control the positions and velocities under the external wave, current, and tether forces. In the water test using the proposed Python-based GUI platform, it shows that the AUVDH is capable to perform station-keeping under the external disturbances.

  9. Ranking multiple docking solutions based on the conservation of inter-residue contacts

    KAUST Repository

    Oliva, Romina M.; Vangone, Anna; Cavallo, Luigi

    2013-01-01

    ) conformations in the top positions is still an open problem. Herein we present CONSRANK, a simple and effective tool to rank multiple docking solutions, which relies on the conservation of inter-residue contacts in the analyzed decoys ensemble. First

  10. Modelling and control of neutron and synchrotron beamline positioning systems

    Energy Technology Data Exchange (ETDEWEB)

    Nneji, S.O., E-mail: Stephen.nneji@open.ac.uk [The Open University, Materials Engineering, Walton Hall, Milton Keynes, Buckinghamshire MK7 6AA (United Kingdom); Science and Technology Facility Council , Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX110QX Oxfordshire (United Kingdom); Zhang, S.Y.; Kabra, S. [Science and Technology Facility Council , Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX110QX Oxfordshire (United Kingdom); Moat, R.J.; James, J.A. [The Open University, Materials Engineering, Walton Hall, Milton Keynes, Buckinghamshire MK7 6AA (United Kingdom)

    2016-03-21

    Measurement of residual stress using neutron or synchrotron diffraction relies on the accurate alignment of the sample in relation to the gauge volume of the instrument. Automatic sample alignment can be achieved using kinematic models of the positioning system provided the relevant kinematic parameters are known, or can be determined, to a suitable accuracy. In this paper, the use of techniques from robotic calibration theory to generate kinematic models of both off-the-shelf and custom-built positioning systems is demonstrated. The approach is illustrated using a positioning system in use on the ENGIN-X instrument at the UK's ISIS pulsed neutron source comprising a traditional XYZΩ table augmented with a triple axis manipulator. Accuracies better than 100 microns were achieved for this compound system. Discussed here in terms of sample positioning systems these methods are entirely applicable to other moving instrument components such as beam shaping jaws and detectors.

  11. PSOVina: The hybrid particle swarm optimization algorithm for protein-ligand docking.

    Science.gov (United States)

    Ng, Marcus C K; Fong, Simon; Siu, Shirley W I

    2015-06-01

    Protein-ligand docking is an essential step in modern drug discovery process. The challenge here is to accurately predict and efficiently optimize the position and orientation of ligands in the binding pocket of a target protein. In this paper, we present a new method called PSOVina which combined the particle swarm optimization (PSO) algorithm with the efficient Broyden-Fletcher-Goldfarb-Shannon (BFGS) local search method adopted in AutoDock Vina to tackle the conformational search problem in docking. Using a diverse data set of 201 protein-ligand complexes from the PDBbind database and a full set of ligands and decoys for four representative targets from the directory of useful decoys (DUD) virtual screening data set, we assessed the docking performance of PSOVina in comparison to the original Vina program. Our results showed that PSOVina achieves a remarkable execution time reduction of 51-60% without compromising the prediction accuracies in the docking and virtual screening experiments. This improvement in time efficiency makes PSOVina a better choice of a docking tool in large-scale protein-ligand docking applications. Our work lays the foundation for the future development of swarm-based algorithms in molecular docking programs. PSOVina is freely available to non-commercial users at http://cbbio.cis.umac.mo .

  12. Positive polynomials and robust stabilization with fixed-order controllers

    Czech Academy of Sciences Publication Activity Database

    Henrion, Didier; Šebek, M.; Kučera, V.

    2003-01-01

    Roč. 48, č. 7 (2003), s. 1178-1186 ISSN 0018-9286 R&D Projects: GA ČR GA102/02/0709; GA MŠk ME 496 Institutional research plan: CEZ:AV0Z1075907 Keywords : fixed-order control lers * linear matrix inequality * polynomials, robust control Subject RIV: BC - Control Systems Theory Impact factor: 1.896, year: 2003

  13. Modeling, Simulation and Position Control of 3DOF Articulated Manipulator

    Directory of Open Access Journals (Sweden)

    Hossein Sadegh Lafmejani

    2014-08-01

    Full Text Available In this paper, the modeling, simulation and control of 3 degrees of freedom articulated robotic manipulator have been studied. First, we extracted kinematics and dynamics equations of the mentioned manipulator by using the Lagrange method. In order to validate the analytical model of the manipulator we compared the model simulated in the simulation environment of Matlab with the model was simulated with the SimMechanics toolbox. A sample path has been designed for analyzing the tracking subject. The system has been linearized with feedback linearization and then a PID controller was applied to track a reference trajectory. Finally, the control results have been compared with a nonlinear PID controller.

  14. Longitudinal Bunch Position Control for the Super-B Accelerator

    International Nuclear Information System (INIS)

    Bertsche, Kirk; Rivetta, Claudio; Sullivam, Michael K.; SLAC; Drago, Alessandro; Frascati

    2009-01-01

    The use of normal conducting cavities and an ion-clearing gap will cause a significant RF accelerating voltage gap transient and longitudinal phase shift of the individual bunches along the bunch train in both rings of the SuperB accelerator. Small relative centroid position shifts between bunches of the colliding beams will have a large adverse impact on the luminosity due to the small β* y at the interaction point (IP). We investigate the possibility of minimizing the relative longitudinal position shift between bunches by reducing the gap transient in each ring and matching the longitudinal bunch positions of the two rings at the IP using feedback/feedforward techniques in the LLRF. The analysis is conducted assuming maximum use of the klystron power installed in the system

  15. Technology Development of Automated Rendezvous and Docking/Capture Sensors and Docking Mechanism for the Asteroid Redirect Crewed Mission

    Science.gov (United States)

    Hinkel, Heather; Strube, Matthew; Zipay, John J.; Cryan, Scott

    2016-01-01

    This paper will describe the technology development efforts NASA has underway for Automated Rendezvous and Docking/Capture (AR&D/C) sensors and a docking mechanism and the challenges involved. The paper will additionally address how these technologies will be extended to other missions requiring AR&D/C whether robotic or manned. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion spacecraft. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a three-dimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build-time instead of at design-time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal non-recurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. These sensor specifications are tightly coupled to the docking system capabilities and requirements for final docking conditions. The paper will describe NASA's efforts to develop a standard docking system for use across NASA human spaceflight missions to multiple destinations. It will describe the current

  16. Digital feed back control for radial beam position

    International Nuclear Information System (INIS)

    Mestha, L.K.

    1989-09-01

    In the development of wide spread large scale distributed digital control systems, there is a requirement to automate small processes like radial beam control which will not only improve the beam quality but will also add local intelligence. Hence use is made here of digital control principles for such applications. The work concerned with the radial beam control discussed in this report has been developed for ISIS at RAL. The structure of the report is hence inclined more towards the local hardware system. The general feed back loop techniques can also be implemented for other control purpose. For instance, the author has successfully tested similar techniques to minimise the RF cavity tuning error, where the improvement in performance could not be matched by the analogue loop. A description of the RF cavity tuning programme and the associated experimental results will be published as a local paper for ISIS division. (author)

  17. Experimental Robustness Study of Positive Position Feedback Control for Active Vibration Suppression

    Science.gov (United States)

    2001-01-01

    several distinguished advantagesas compared to thenwidely used velocity feedbackcon- trol laws. It is insensitive to spillover,2 where contributions from...be known exactlyor itmayvarywith time.When the frequencyused in thePPF controller is different from that of the structure, the performanceof the PPF...revision received 30 July 2001; accepted for pub- lication 7 September 2001. This material is declared a work of the U.S. Government and is not subject

  18. Dimerization of DOCK2 is essential for DOCK2-mediated Rac activation and lymphocyte migration.

    Directory of Open Access Journals (Sweden)

    Masao Terasawa

    Full Text Available The migratory properties of lymphocytes depend on DOCK2, an atypical Rac activator predominantly expressed in hematopoietic cells. Although DOCK2 does not contain the Dbl homology domain typically found in guanine nucleotide exchange factors (GEFs, DOCK2 mediates the GTP-GDP exchange reaction for Rac via its DOCK homology region (DHR-2 (also known as CZH2 or Docker domain. DOCK2 DHR-2 domain is composed of three lobes, and Rac binding site and catalytic center are generated entirely from lobes B and C. On the other hand, lobe A has been implicated in dimer formation, yet its physiological significance remains unknown. Here, we report that lobe A-mediated DOCK2 dimerization is crucial for Rac activation and lymphocyte migration. We found that unlike wild-type DOCK2, DOCK2 mutant lacking lobe A failed to restore motility and polarity when expressed in thymoma cells and primary T cells lacking endogenous expression of DOCK2. Similar results were obtained with the DOCK2 point mutant having a defect in dimerization. Deletion of lobe A from the DHR-2 domain did not affect Rac GEF activity in vitro. However, fluorescence resonance energy transfer analyses revealed that lobe A is required for DOCK2 to activate Rac effectively during cell migration. Our results thus indicate that DOCK2 dimerization is functionally important under the physiological condition where only limited amounts of DOCK2 and Rac are localized to the plasma membrane.

  19. Tool position tracking control of a nonlinear uncertain flexible robot ...

    Indian Academy of Sciences (India)

    Moreover, other different papers and thesis of flexible manipulators ... various applications is highly sensitive to variations of disturbance torque acting on ...... Dang X 2014 Robust adaptive sliding-mode control of condenser-cleaning mobile.

  20. Rendezvous and Docking Technology for Space Flight%空间交会对接技术

    Institute of Scientific and Technical Information of China (English)

    郑永煌

    2011-01-01

    空间交会对接是载人航天工程非常重要的基本技术.在介绍空间交会对接技术发展历史和中国首次交会对接取得圆满成功的基础上,阐述了空间交会对接技术的基本概念、技术难点、控制方式和交会对接过程,并着重介绍了四种交会对接机构的特点.最后介绍了中国首次交会对接任务规划、天宫一号目标飞行器和神舟八号飞船的特点以及两次空间交会对接过程.%Rendezvous and Docking is a very important basic technology of Manned Space Engineering. Firstly, rendezvous and docking technology development history is provided, and the significance of China first rendezvous and docking success is presented. Secondly, the basic conception, technology difficulty, control mode and docking process of rendezvous and docking technology are explained.Thirdly, four docking mechanism characteristics are special provided. Finally, China first rendezvous and docking mission planning,characteristic of Tiangong-1 target flight vehicle and Shenzhou-8 spacecraft and two rendezvous and docking successes are presented.

  1. Positive valence music restores executive control over sustained attention.

    Science.gov (United States)

    Baldwin, Carryl L; Lewis, Bridget A

    2017-01-01

    Music sometimes improves performance in sustained attention tasks. But the type of music employed in previous investigations has varied considerably, which can account for equivocal results. Progress has been hampered by lack of a systematic database of music varying in key characteristics like tempo and valence. The aims of this study were to establish a database of popular music varying along the dimensions of tempo and valence and to examine the impact of music varying along these dimensions on restoring attentional resources following performance of a sustained attention to response task (SART) vigil. Sixty-nine participants rated popular musical selections that varied in valence and tempo to establish a database of four musical types: fast tempo positive valence, fast tempo negative valence, slow tempo positive valence, and slow tempo negative valence. A second group of 89 participants performed two blocks of the SART task interspersed with either no break or a rest break consisting of 1 of the 4 types of music or silence. Presenting positive valence music (particularly of slow tempo) during an intermission between two successive blocks of the SART significantly decreased miss rates relative to negative valence music or silence. Results support an attentional restoration theory of the impact of music on sustained attention, rather than arousal theory and demonstrate a means of restoring sustained attention. Further, the results establish the validity of a music database that will facilitate further investigations of the impact of music on performance.

  2. Positive emotion, reward, and cognitive control: emotional versus motivational influences

    Directory of Open Access Journals (Sweden)

    Kimberly Sarah Chiew

    2011-10-01

    Full Text Available It is becoming increasingly appreciated that affective influences can contribute strongly to goal-oriented cognition and behaviour. However, much work is still needed to properly characterize these influences and the mechanisms by which they contribute to cognitive processing. An important question concerns the nature of emotional manipulations (i.e., direct induction of affectively-valenced subjective experience versus motivational manipulations (e.g., delivery of performance-contingent rewards and punishments and their impact on cognitive control. Empirical evidence suggests that both kinds of manipulations can influence cognitive control in a systematic fashion, but investigations of both have largely been conducted independently of one another. Likewise, some theoretical accounts suggest that emotion and motivation may modulate cognitive control via common neural mechanisms, while others suggest the possibility of dissociable influences. Here, we provide an analysis and synthesis of these various accounts, suggesting potentially fruitful new research directions to test competing hypotheses.

  3. Control of plasma column horizontal position in TBR-1

    International Nuclear Information System (INIS)

    Tuszel, A.G.; Rincoski, C.R.M.

    1990-01-01

    The TBR-1 is a small tokamak built at the Physics Institute of the University of Sao Paulo. It was originally designed with a simple vertical field power supply made of one fast capacitor bank for vertical current build-up and one slow capacitor bank for flat-top phase, without any control but the adjustable initial voltages of the capacitors. With such an elementary system, the plasma cannot be held in the center of the vacuum vessel for the whole duration of the plasma. This led to a suboptimal performance with easy disruptions. A control system was designed to hold the plasma centered in the radial coordinate. (Author)

  4. Position-controlled epitaxial III-V nanowires on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Roest, Aarnoud L; Verheijen, Marcel A; Wunnicke, Olaf; Serafin, Stacey; Wondergem, Harry; Bakkers, Erik P A M [Philips Research Laboratories, Professor Holstlaan 4, 5656 AA Eindhoven (Netherlands); Kavli Institute of NanoScience, Delft University of Technology, PO Box 5046, 2600 GA Delft (Netherlands)

    2006-06-14

    We show the epitaxial integration of III-V semiconductor nanowires with silicon technology. The wires are grown by the VLS mechanism with laser ablation as well as metal-organic vapour phase epitaxy. The hetero-epitaxial growth of the III-V nanowires on silicon was confirmed with x-ray diffraction pole figures and cross-sectional transmission electron microscopy. We show preliminary results of two-terminal electrical measurements of III-V nanowires grown on silicon. E-beam lithography was used to predefine the position of the nanowires.

  5. Position-controlled epitaxial III-V nanowires on silicon

    International Nuclear Information System (INIS)

    Roest, Aarnoud L; Verheijen, Marcel A; Wunnicke, Olaf; Serafin, Stacey; Wondergem, Harry; Bakkers, Erik P A M

    2006-01-01

    We show the epitaxial integration of III-V semiconductor nanowires with silicon technology. The wires are grown by the VLS mechanism with laser ablation as well as metal-organic vapour phase epitaxy. The hetero-epitaxial growth of the III-V nanowires on silicon was confirmed with x-ray diffraction pole figures and cross-sectional transmission electron microscopy. We show preliminary results of two-terminal electrical measurements of III-V nanowires grown on silicon. E-beam lithography was used to predefine the position of the nanowires

  6. Electro-Pneumatic Control System with Hydraulically Positioning Actuator Motor

    OpenAIRE

    V. N. Pilgunov; K. D. Efremova

    2016-01-01

    A compressibility of the actuating fluid of a pneumatic drive (compressed air) leads to significant landing of the pneumatic cylinder piston at the time of stop and hold of the load, a constant component of which can fluctuate significantly for the holding period.There are a lot of factors, which have a significant impact on the landing value of piston. Those are: an initial position of the piston at its stop, which determines the volume of the an active area of the piston, a value of the con...

  7. Beam position monitor readout and control in the SLC linac

    International Nuclear Information System (INIS)

    Bogart, J.; Phinney, N.; Ross, M.; Yaffe, D.

    1985-04-01

    A beam position monitoring system has been implemented in the first third of the SLC linac which provides a complete scan of the trajectory on a single beam pulse. The data is collected from the local micro-computers and viewed with an updating display at a console or passed on to application programs. The system must operate with interlaced beams so the scans are also interlaced, providing each user with the ability to select the beam, the update rate, and the attenuation level in the digitizing hardware. In addition each user calibrates the hardware for his beam. A description of the system architecture will be presented. 6 refs., 4 figs

  8. Robust combined position and formation control for marine surface craft

    DEFF Research Database (Denmark)

    Ihle, Ivar-Andre F.; Jouffroy, Jerome; Fossen, Thor I.

    We consider the robustness properties of a formation control system for marine surface vessels. Intervessel constraint functions are stabilized to achieve the desired formation configuration. We show that the formation dynamics is Input-to-State Stable (ISS) to both environmental perturbations th...

  9. Position control of a wheeled mobile robot including tire behavior

    NARCIS (Netherlands)

    Ploeg, J.; Schouten, H.E.; Nijmeijer, H.

    2009-01-01

    Advanced driver assistance systems are increasingly available on road vehicles. These systems require a thorough development procedure, an important part of which consists of hardware-in-the-loop experiments in a controlled environment. To this end, a facility called Vehicle Hardware-In-the-Loop

  10. Application of the docking program SOL for CSAR benchmark.

    Science.gov (United States)

    Sulimov, Alexey V; Kutov, Danil C; Oferkin, Igor V; Katkova, Ekaterina V; Sulimov, Vladimir B

    2013-08-26

    This paper is devoted to results obtained by the docking program SOL and the post-processing program DISCORE at the CSAR benchmark. SOL and DISCORE programs are described. SOL is the original docking program developed on the basis of the genetic algorithm, MMFF94 force field, rigid protein, precalculated energy grid including desolvation in the frame of simplified GB model, vdW, and electrostatic interactions and taking into account the ligand internal strain energy. An important SOL feature is the single- or multi-processor performance for up to hundreds of CPUs. DISCORE improves the binding energy scoring by the local energy optimization of the ligand docked pose and a simple linear regression on the base of available experimental data. The docking program SOL has demonstrated a good ability for correct ligand positioning in the active sites of the tested proteins in most cases of CSAR exercises. SOL and DISCORE have not demonstrated very exciting results on the protein-ligand binding free energy estimation. Nevertheless, for some target proteins, SOL and DISCORE were among the first in prediction of inhibition activity. Ways to improve SOL and DISCORE are discussed.

  11. Lateral position detection and control for friction stir systems

    Science.gov (United States)

    Fleming, Paul; Lammlein, David; Cook, George E.; Wilkes, Don Mitchell; Strauss, Alvin M.; Delapp, David; Hartman, Daniel A.

    2010-12-14

    A friction stir system for processing at least a first workpiece includes a spindle actuator coupled to a rotary tool comprising a rotating member for contacting and processing the first workpiece. A detection system is provided for obtaining information related to a lateral alignment of the rotating member. The detection system comprises at least one sensor for measuring a force experienced by the rotary tool or a parameter related to the force experienced by the rotary tool during processing, wherein the sensor provides sensor signals. A signal processing system is coupled to receive and analyze the sensor signals and determine a lateral alignment of the rotating member relative to a selected lateral position, a selected path, or a direction to decrease a lateral distance relative to the selected lateral position or selected path. In one embodiment, the friction stir system can be embodied as a closed loop tracking system, such as a robot-based tracked friction stir welding (FSW) or friction stir processing (FSP) system.

  12. Preliminary performance test of control rod position indicator for ballscrew type CEDM

    International Nuclear Information System (INIS)

    Yoo, J. Y.; Kim, J. H.; Hu, H.; Lee, J. S.; Kim, J. I.

    2003-01-01

    The reliability and accuracy of the information on control rod position are very important to the reactor safety and the design of the core protection system. A survey on the RSPT(Reed Switch Position Transmitter) type control rod position indication system and its actual implementation in the exiting nuclear power plants in Korea was performed first. The prototype of control rod position indicator having the high performance for the ballscrew type CEDM was developed on the basis of RSPT technology identified through the survey. The characteristics of control rod position indicator was defined and documented through design procedure and preliminary performance test

  13. [Ligament-controlled positioning of the knee prosthesis components].

    Science.gov (United States)

    Widmer, K-H; Zich, A

    2015-04-01

    There are at least two predominant goals in total knee replacement: first, the surgeon aims to achieve an optimal postoperative kinematic motion close to the patient's physiological range, and second, he aims for concurrent high ligament stability to establish pain-free movement for the entire range of motion. A number of prosthetic designs and surgical techniques have been developed in recent years to achieve both of these targets. This study presents another modified surgical procedure for total knee implantation. As in common practice the osteotomies are planned preoperatively, referencing well-defined bony landmarks, but their placement and orientation are also controlled intraoperatively in a stepwise sequence via ligamentous linkages. This method is open to all surgical approaches and can be applied for PCL-conserving or -sacrificing techniques. The anterior femoral osteotomy is carried out first, followed by the distal femoral osteotomy. Then, the extension gap is finalized by tensioning the ligaments and "top-down" referencing at the level of the tibial osteotomy, followed by finishing the flexion gap in the same way, except that the osteotomy of the posterior condyles is referenced in a "bottom-up" fashion. Hence, this technique relies on both bony and ligament-controlled procedures. Thus, it respects the modified ligamentous framework and drives the prosthetic components into the new ligamentous envelope. Further improvement may be achieved by additional control of the kinematics during surgery by applying modern computer navigation technology.

  14. Control of Position for a Telescope with Stepping Motors

    OpenAIRE

    Quintero Salazar, Edwin Andrés; Gallego Becerra, Hugo Armando; Gallego Orozco, Hoover

    2008-01-01

    En este documento se muestran los resultados obtenidos al construir un control electrónico de posición para un telescopio reflector de 15 cm de objetivo, con motores paso a paso manejados desde un microcontrolador. También se ilustra el diseño circuital realizado, la simulación obtenida en la herramienta informática Proteus, el software desarrollado en lenguaje ensamblador para el microcontrolador, y el circuito final resultante montado sobre protoboard. In this paper the obtained resul...

  15. Evaluation of Docking Target Functions by the Comprehensive Investigation of Protein-Ligand Energy Minima.

    Science.gov (United States)

    Oferkin, Igor V; Katkova, Ekaterina V; Sulimov, Alexey V; Kutov, Danil C; Sobolev, Sergey I; Voevodin, Vladimir V; Sulimov, Vladimir B

    2015-01-01

    The adequate choice of the docking target function impacts the accuracy of the ligand positioning as well as the accuracy of the protein-ligand binding energy calculation. To evaluate a docking target function we compared positions of its minima with the experimentally known pose of the ligand in the protein active site. We evaluated five docking target functions based on either the MMFF94 force field or the PM7 quantum-chemical method with or without implicit solvent models: PCM, COSMO, and SGB. Each function was tested on the same set of 16 protein-ligand complexes. For exhaustive low-energy minima search the novel MPI parallelized docking program FLM and large supercomputer resources were used. Protein-ligand binding energies calculated using low-energy minima were compared with experimental values. It was demonstrated that the docking target function on the base of the MMFF94 force field in vacuo can be used for discovery of native or near native ligand positions by finding the low-energy local minima spectrum of the target function. The importance of solute-solvent interaction for the correct ligand positioning is demonstrated. It is shown that docking accuracy can be improved by replacement of the MMFF94 force field by the new semiempirical quantum-chemical PM7 method.

  16. Evaluation of Docking Target Functions by the Comprehensive Investigation of Protein-Ligand Energy Minima

    Directory of Open Access Journals (Sweden)

    Igor V. Oferkin

    2015-01-01

    Full Text Available The adequate choice of the docking target function impacts the accuracy of the ligand positioning as well as the accuracy of the protein-ligand binding energy calculation. To evaluate a docking target function we compared positions of its minima with the experimentally known pose of the ligand in the protein active site. We evaluated five docking target functions based on either the MMFF94 force field or the PM7 quantum-chemical method with or without implicit solvent models: PCM, COSMO, and SGB. Each function was tested on the same set of 16 protein-ligand complexes. For exhaustive low-energy minima search the novel MPI parallelized docking program FLM and large supercomputer resources were used. Protein-ligand binding energies calculated using low-energy minima were compared with experimental values. It was demonstrated that the docking target function on the base of the MMFF94 force field in vacuo can be used for discovery of native or near native ligand positions by finding the low-energy local minima spectrum of the target function. The importance of solute-solvent interaction for the correct ligand positioning is demonstrated. It is shown that docking accuracy can be improved by replacement of the MMFF94 force field by the new semiempirical quantum-chemical PM7 method.

  17. Mayer control problem with probabilistic uncertainty on initial positions

    Science.gov (United States)

    Marigonda, Antonio; Quincampoix, Marc

    2018-03-01

    In this paper we introduce and study an optimal control problem in the Mayer's form in the space of probability measures on Rn endowed with the Wasserstein distance. Our aim is to study optimality conditions when the knowledge of the initial state and velocity is subject to some uncertainty, which are modeled by a probability measure on Rd and by a vector-valued measure on Rd, respectively. We provide a characterization of the value function of such a problem as unique solution of an Hamilton-Jacobi-Bellman equation in the space of measures in a suitable viscosity sense. Some applications to a pursuit-evasion game with uncertainty in the state space is also discussed, proving the existence of a value for the game.

  18. Ranking multiple docking solutions based on the conservation of inter-residue contacts

    KAUST Repository

    Oliva, Romina M.

    2013-06-17

    Molecular docking is the method of choice for investigating the molecular basis of recognition in a large number of functional protein complexes. However, correctly scoring the obtained docking solutions (decoys) to rank native-like (NL) conformations in the top positions is still an open problem. Herein we present CONSRANK, a simple and effective tool to rank multiple docking solutions, which relies on the conservation of inter-residue contacts in the analyzed decoys ensemble. First it calculates a conservation rate for each inter-residue contact, then it ranks decoys according to their ability to match the more frequently observed contacts. We applied CONSRANK to 102 targets from three different benchmarks, RosettaDock, DOCKGROUND, and Critical Assessment of PRedicted Interactions (CAPRI). The method performs consistently well, both in terms of NL solutions ranked in the top positions and of values of the area under the receiver operating characteristic curve. Its ideal application is to solutions coming from different docking programs and procedures, as in the case of CAPRI targets. For all the analyzed CAPRI targets where a comparison is feasible, CONSRANK outperforms the CAPRI scorers. The fraction of NL solutions in the top ten positions in the RosettaDock, DOCKGROUND, and CAPRI benchmarks is enriched on average by a factor of 3.0, 1.9, and 9.9, respectively. Interestingly, CONSRANK is also able to specifically single out the high/medium quality (HMQ) solutions from the docking decoys ensemble: it ranks 46.2 and 70.8% of the total HMQ solutions available for the RosettaDock and CAPRI targets, respectively, within the top 20 positions. © 2013 Wiley Periodicals, Inc.

  19. Explicit Generalized Predictive Control of Speed and Position of PMSM Drives

    Czech Academy of Sciences Publication Activity Database

    Belda, Květoslav; Vošmik, D.

    2016-01-01

    Roč. 63, č. 6 (2016), s. 3889-3896 ISSN 0278-0046 Institutional support: RVO:67985556 Keywords : current limitation * field weakening * motion control * permanent magnet synchronous motors * position control * predictive control * speed control Subject RIV: BC - Control Systems Theory Impact factor: 7.168, year: 2016 http://library.utia.cas.cz/separaty/2016/AS/belda-0457259.pdf

  20. GalaxyDock BP2 score: a hybrid scoring function for accurate protein-ligand docking

    Science.gov (United States)

    Baek, Minkyung; Shin, Woong-Hee; Chung, Hwan Won; Seok, Chaok

    2017-07-01

    Protein-ligand docking is a useful tool for providing atomic-level understanding of protein functions in nature and design principles for artificial ligands or proteins with desired properties. The ability to identify the true binding pose of a ligand to a target protein among numerous possible candidate poses is an essential requirement for successful protein-ligand docking. Many previously developed docking scoring functions were trained to reproduce experimental binding affinities and were also used for scoring binding poses. However, in this study, we developed a new docking scoring function, called GalaxyDock BP2 Score, by directly training the scoring power of binding poses. This function is a hybrid of physics-based, empirical, and knowledge-based score terms that are balanced to strengthen the advantages of each component. The performance of the new scoring function exhibits significant improvement over existing scoring functions in decoy pose discrimination tests. In addition, when the score is used with the GalaxyDock2 protein-ligand docking program, it outperformed other state-of-the-art docking programs in docking tests on the Astex diverse set, the Cross2009 benchmark set, and the Astex non-native set. GalaxyDock BP2 Score and GalaxyDock2 with this score are freely available at http://galaxy.seoklab.org/softwares/galaxydock.html.

  1. Development of control rod position indicator using seismic-resistance reed switches for integral reactor

    International Nuclear Information System (INIS)

    Yu, Je Yong; Kim, Ji Ho; Huh, Hyung; Choi, Myoung Hwan; Sohn, Dong Seong

    2008-01-01

    The Reed Switch Position Transmitter (RSPT) is used as a position indicator for the control rod in commercial nuclear power plants made by ABB-CE. But this position indicator has some problems when directly adopting it to the integral reactor. The Control Element Drive Mechanism (CEDM) for the integral reactor is designed to raise and lower the control rod in steps of 2mm in order to satisfy the design features of the integral reactor which are the soluble boron free operation and the use of a nuclear heating for the reactor start-up. Therefore the resolution of the position indicator for the integral reactor should be achieved to sense the position of the control rod more precisely than that of the RSPT of the ABB-CE. This paper adopts seismic resistance reed switches to the position indicator in order to reduce the damages or impacts during the handling of the position indicator and earthquake

  2. New approach for control rod position indication system for light water power reactor

    International Nuclear Information System (INIS)

    Bahuguna, Sushil; Dhage, Sangeeta; Nawaj, S.; Salek, C.; Lahiri, S.K.; Marathe, P.P.; Mukhopadhyay, S.; Taly, Y.K.

    2015-01-01

    Control rod position indication system is an important system in a nuclear power plant to monitor and display control rod position in all regimes of reactor operation. A new approach to design a control rod position indication system for sensing absolute position of control rod in Light Water Power Reactor has been undertaken. The proposed system employs an inductive type, hybrid measurement strategy providing both analog position as well as digital zone indication with built-in temperature compensation. The new design approach meets single failure criterion through redundancy in design without sacrificing measurement resolution. It also provides diversity in measurement technique by indirect position sensing based on analysis of drive coil current signature. Prototype development and qualification at room temperature of the control rod position indication system (CRPIS) has been demonstrated. The article presents the design philosophy of control rod position indication system, the new measurement strategy for sensing absolute position of control rod, position estimation algorithm for both direct and indirect sensing and a brief account associated processing electronics. (author)

  3. Robust Operation of Tendon-Driven Robot Fingers Using Force and Position-Based Control Laws

    Science.gov (United States)

    Abdallah, Muhammad E (Inventor); Platt, Jr., Robert J. (Inventor); Reiland, Matthew J (Inventor); Hargrave, Brian (Inventor); Diftler, Myron A (Inventor); Strawser, Philip A (Inventor); Ihrke, Chris A. (Inventor)

    2013-01-01

    A robotic system includes a tendon-driven finger and a control system. The system controls the finger via a force-based control law when a tension sensor is available, and via a position-based control law when a sensor is not available. Multiple tendons may each have a corresponding sensor. The system selectively injects a compliance value into the position-based control law when only some sensors are available. A control system includes a host machine and a non-transitory computer-readable medium having a control process, which is executed by the host machine to control the finger via the force- or position-based control law. A method for controlling the finger includes determining the availability of a tension sensor(s), and selectively controlling the finger, using the control system, via the force or position-based control law. The position control law allows the control system to resist disturbances while nominally maintaining the initial state of internal tendon tensions.

  4. Mathematical Modeling and Kinematics Analysis of Double Spherical Shell Rotary Docking Skirt

    Directory of Open Access Journals (Sweden)

    Gong Haixia

    2017-01-01

    Full Text Available In order to solve the problem of large trim and heel angles of the wrecked submarine, the double spherical shell rotating docking skirt is studied. According to the working principle of the rotating docking skirt, and the fixed skirt, the directional skirt, the angle skirt are simplified as the connecting rod. Therefore, the posture equation and kinematics model of the docking skirt are deduced, and according to the kinematics model, the angle of rotation of the directional skirt and the angle skirt is obtained when the wrecked submarine is in different trim and heel angles. Through the directional skirt and angle skirt with the matching rotation can make docking skirt interface in the 0°~2γ range within the rotation, to complete the docking skirt and the wrecked submarine docking. The MATLAB software is used to visualize the rotation angle of fixed skirt and directional skirt, which lays a good foundation for the development of the control of the double spherical shell rotating docking skirt in future.

  5. Design and performance analysis of position-based impedance control for an electrohydrostatic actuation system

    Directory of Open Access Journals (Sweden)

    Yongling FU

    2018-03-01

    Full Text Available Electrohydrostatic actuator (EHA is a type of power-by-wire actuator that is widely implemented in the aerospace industry for flight control, landing gears, thrust reversers, thrust vector control, and space robots. This paper presents the development and evaluation of position-based impedance control (PBIC for an EHA. Impedance control provides the actuator with compliance and facilitates the interaction with the environment. Most impedance control applications utilize electrical or valve-controlled hydraulic actuators, whereas this work realizes impedance control via a compact and efficient EHA. The structures of the EHA and PBIC are firstly introduced. A mathematical model of the actuation system is established, and values of its coefficients are identified by particle swarm optimization. This model facilitates the development of a position controller and the selection of target impedance parameters. A nonlinear proportional-integral position controller is developed for the EHA to achieve the accurate positioning requirement of PBIC. The controller compensates for the adverse effect of stiction, and a position accuracy of 0.08 mm is attained. Various experimental results are presented to verify the applicability of PBIC to the EHA. The compliance of the actuator is demonstrated in an impact test. Keywords: Actuation system, Aerospace, Electrohydrostatic actuator, Force control, Nonlinear dynamics, Particle swarm optimization, Position control

  6. Computational methods for molecular docking

    Energy Technology Data Exchange (ETDEWEB)

    Klebe, G. [BASF AG, Ludwigshafen (Germany); Lengauer, T.

    1995-12-31

    This tutorial was one of eight tutorials selected to be presented at the Third International Conference on Intelligent Systems for Molecular Biology which was held in the United Kingdom from July 16 to 19, 1995. Recently, it has been demonstrated that the knowledge of the three-dimensional structure of the protein can be used to derive new protein ligands with improved binding properties. This tutorial focuses on the following questions: What is its binding affinity toward a particular receptor? What are putative conformations of a ligand at the binding site? What are the similarities of different ligands in terms of their recognition capabilities? Where and in which orientation will a ligand bind to the active site? How is a new putative protein ligand selected? An overview is presented of the algorithms which are presently used to handle and predict protein-ligand interactions and to dock small molecule ligands into proteins.

  7. A modern automatic Carriage-Trolley Position Control System for Dhruva fuelling machine

    International Nuclear Information System (INIS)

    Agrawal, Ankit; Hari Balakrishna; Narvekar, J.P.; Sanadhya, Vivek

    2014-01-01

    A fully automatic absolute encoder based position control system has been designed developed implemented and commissioned for the Dhruva Fuelling Machine A (FM/A). This supports both the coarse and fine positioning modes. Provision for fully manual positioning as a standby system has been retained. This system replaces the ageing peg counting based incremental positioner used briefly during the early period after the Dhruva FM/A was commissioned. The older system suffered from peg detection skipping problems; hence it was not being used. Only full manual positioning was being carried out. This paper describes the automatic Carriage Trolley Position Control System (CTPCS). (author)

  8. 78 FR 979 - Petition for Positive Train Control Safety Plan Approval and System Certification of the...

    Science.gov (United States)

    2013-01-07

    ...] Petition for Positive Train Control Safety Plan Approval and System Certification of the Electronic Train... the Federal Railroad Administration (FRA) for Positive Train Control (PTC) Safety Plan (PTCSP) approval and system certification of the Electronic Train Management System (ETMS) as required by 49 U.S.C...

  9. Effects of wood preservative leachates from docks

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, P.H.; Van Dolah, R.F.; Bobo, M.Y.; Mathews, T.D. [South Carolina Marine Resources Research Inst., Charleston, SC (United States)

    1994-12-31

    Recent evidence indicates that the wood preservative commonly used in dock pilings (chromated copper arsenate or CCA) is highly toxic to several estuarine organisms in laboratory experiments. Increasing demand for residential docks prompted a field study intended to complement these earlier laboratory investigations. Objectives of the study were to: (1) examine concentrations of Cu, Cr, and As in sediments and oysters from intertidal locations in several creeks with and without high densities of docks; (2) examine the bioaccumulation of wood preservative leachates by laboratory-reared oysters transferred to field sites near and distant from newly constructed docks; and (3) investigate the acute toxicity of wood preservative leachates for several species of estuarine fishes and invertebrates exposed to these compounds in the field. Preliminary results indicate that sediment concentrations of all three metals were well below ER-L levels reported by Long and Morgan at all but one dock site. In an ancillary study, 24h LC{sub 50} bioassays were performed using rotifers (Brachionus plicatilis) which were exposed to pore water from sediments in creeks with and without docks. Toxicities of bulk sediments from the same sites were examined using Microtox which measures decreases in bioluminescence of marine bacteria (Photobacterium phosphoreum) as a function of sediment concentration. Neither the rotifer nor the Microtox bioassays showed any significant differences in toxicity between creeks with and without docks.

  10. Automatic beam position control at Los Alamos Spallation Radiation Effects Facility (LASREF)

    International Nuclear Information System (INIS)

    Oothoudt, M.; Pillai, C.; Zumbro, M.

    1997-01-01

    Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual methods to control the position of the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp is used to automatically adjust steering magnets to maintain beam position to required tolerances

  11. Feedback control of horizontal position and plasma surface shape in a non-circular tokamak

    International Nuclear Information System (INIS)

    Moriyama, Shin-ichi; Nakamura, Kazuo; Nakamura, Yukio; Itoh, Satoshi

    1986-01-01

    The linear model for the coupled horizontal position and plasma surface shape control in the non-circular tokamak device was described. It enables us to estimate easily the displacement and the distortion due to the changes in plasma pressure and current density distribution. The PI-controller and the optimal regulator were designed with the linear model. Transient-response analysis of the control system in the TRIAM-1M tokamak showed that the optimal regulator is superior to the PI-controller with regard to the mutual-interference between the position control system and the elongation control system. (author)

  12. POSITION CONTROL OF BRUSHLESS DC MOTOR BASED ON DIGITAL SIGNAL PROCESSING

    Directory of Open Access Journals (Sweden)

    Çetin GENÇER

    2006-01-01

    Full Text Available Brushless DC Motors (BLDC have been used widely high performance control systems which are depended on to development of power electronic and control technology. In these motors to fed commutated supply, the control of position without oscilation has been required. In this study, position control of BLDC with digital signal processing has been implemented by a proportional-derivative (PD controller because of its simple structure. It has been seen that the controller which is proposed from simulation and experimental studies, has a quick dynamic responce with nonoscillation.

  13. Evaluation of the novel algorithm of flexible ligand docking with moveable target-protein atoms.

    Science.gov (United States)

    Sulimov, Alexey V; Zheltkov, Dmitry A; Oferkin, Igor V; Kutov, Danil C; Katkova, Ekaterina V; Tyrtyshnikov, Eugene E; Sulimov, Vladimir B

    2017-01-01

    We present the novel docking algorithm based on the Tensor Train decomposition and the TT-Cross global optimization. The algorithm is applied to the docking problem with flexible ligand and moveable protein atoms. The energy of the protein-ligand complex is calculated in the frame of the MMFF94 force field in vacuum. The grid of precalculated energy potentials of probe ligand atoms in the field of the target protein atoms is not used. The energy of the protein-ligand complex for any given configuration is computed directly with the MMFF94 force field without any fitting parameters. The conformation space of the system coordinates is formed by translations and rotations of the ligand as a whole, by the ligand torsions and also by Cartesian coordinates of the selected target protein atoms. Mobility of protein and ligand atoms is taken into account in the docking process simultaneously and equally. The algorithm is realized in the novel parallel docking SOL-P program and results of its performance for a set of 30 protein-ligand complexes are presented. Dependence of the docking positioning accuracy is investigated as a function of parameters of the docking algorithm and the number of protein moveable atoms. It is shown that mobility of the protein atoms improves docking positioning accuracy. The SOL-P program is able to perform docking of a flexible ligand into the active site of the target protein with several dozens of protein moveable atoms: the native crystallized ligand pose is correctly found as the global energy minimum in the search space with 157 dimensions using 4700 CPU ∗ h at the Lomonosov supercomputer.

  14. Conceptual Design of Angular Position Detector for Control Element Drive Mechanism of Small and Medium Reactor

    International Nuclear Information System (INIS)

    Yu, Je-Yong; Huh, Hyung; Kim, Ji-Ho; Choi, Suhn

    2007-01-01

    When the small and medium reactor is designed with a soluble boron free operation and nuclear heating for the reactor start-up, the design features require a Control Element Drive Mechanism (CEDM) to have a fine-step movement capability as well as a high reliability for a fine reactivity control. Also the reliability and accuracy of the information for the control rod position is important to the reactor safety as well as to design of the core protection system. The position signal of control rod is classified as a Class 1E because the rod position signal is used in the safety related systems. Therefore it will be separated from the control systems to the extent that a failure of any single control system component of a channel and shall have sufficient independence, redundancy, and testability to perform its safety functions assuming a single failure. The position indicator is composed of a permanent magnet, reed switches and a voltage divider. Four independent position indicators around the upper pressure housing provide an indication of the position of a control rod comprising of a permanent magnet with a magnetic field concentrator which moves with the extension shaft connected to the control rod. The zigzag arranged reed switches are positioned along a line parallel to the path of the movement of the permanent magnet and it is activated selectively when the permanent magnet passes by. A voltage divider electrically connected to the reed switches provides a signal commensurate with the position of the control rod. The signal may then be transmitted to a position indicating device. But position indicator can not recognize the malfunction of the rotary step motor of CEDM instantly because its signal output is changed after the control rod moves more than a distance of reed switch interval

  15. Vehicle routing with cross-docking

    DEFF Research Database (Denmark)

    Wen, Min; Larsen, Jesper; Clausen, Jens

    2009-01-01

    a set of homogeneous vehicles are used to transport orders from the suppliers to the corresponding customers via a cross-dock. The orders can be consolidated at the cross-dock but cannot be stored for very long because the cross-dock does not have long-term inventory-holding capabilities. The objective...... of the VRPCD is to minimize the total travel time while respecting time window constraints at the nodes and a time horizon for the whole transportation operation. In this paper, a mixed integer programming formulation for the VRPCD is proposed. A tabu search heuristic is embedded within an adaptive memory...... values) within very short computational time....

  16. A compound control strategy combining velocity compensation with ADRC of electro-hydraulic position servo control system.

    Science.gov (United States)

    Gao, Bingwei; Shao, Junpeng; Yang, Xiaodong

    2014-11-01

    In order to enhance the anti-jamming ability of electro-hydraulic position servo control system at the same time improve the control precision of the system, a compound control strategy that combines velocity compensation with Active Disturbance Rejection Controller (ADRC) is proposed, and the working principle of the compound control strategy is given. ADRC controller is designed, and the extended state observer is used for observing internal parameters uncertainties and external disturbances, so that the disturbances of the system are suppressed effectively. Velocity compensation controller is designed and the compensation model is derived to further improve the positioning accuracy of the system and to achieve the velocity compensation without disturbance. The compound control strategy is verified by the simulation and experiment respectively, and the simulation and experimental results show that the electro-hydraulic position servo control system with ADRC controller can effectively inhibit the external disturbances, the precise positioning control is realized after introducing the velocity compensation controller, and verify that the compound control strategy is effective. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Vision Based Navigation for Autonomous Cooperative Docking of CubeSats

    Science.gov (United States)

    Pirat, Camille; Ankersen, Finn; Walker, Roger; Gass, Volker

    2018-05-01

    A realistic rendezvous and docking navigation solution applicable to CubeSats is investigated. The scalability analysis of the ESA Autonomous Transfer Vehicle Guidance, Navigation & Control (GNC) performances and the Russian docking system, shows that the docking of two CubeSats would require a lateral control performance of the order of 1 cm. Line of sight constraints and multipath effects affecting Global Navigation Satellite System (GNSS) measurements in close proximity prevent the use of this sensor for the final approach. This consideration and the high control accuracy requirement led to the use of vision sensors for the final 10 m of the rendezvous and docking sequence. A single monocular camera on the chaser satellite and various sets of Light-Emitting Diodes (LEDs) on the target vehicle ensure the observability of the system throughout the approach trajectory. The simple and novel formulation of the measurement equations allows differentiating unambiguously rotations from translations between the target and chaser docking port and allows a navigation performance better than 1 mm at docking. Furthermore, the non-linear measurement equations can be solved in order to provide an analytic navigation solution. This solution can be used to monitor the navigation filter solution and ensure its stability, adding an extra layer of robustness for autonomous rendezvous and docking. The navigation filter initialization is addressed in detail. The proposed method is able to differentiate LEDs signals from Sun reflections as demonstrated by experimental data. The navigation filter uses a comprehensive linearised coupled rotation/translation dynamics, describing the chaser to target docking port motion. The handover, between GNSS and vision sensor measurements, is assessed. The performances of the navigation function along the approach trajectory is discussed.

  18. Attentional control mediates the effect of social anxiety on positive affect☆

    Science.gov (United States)

    Morrison, Amanda S.; Heimberg, Richard G.

    2015-01-01

    The goal of the present studies was to examine whether attentional control, a self-regulatory attentional mechanism, mediates the effect of social anxiety on positive affect. We tested this mediation in two studies using undergraduate students selected to represent a broad range of severity of social anxiety. Self-report assessments of social anxiety, attentional control, and positive affect were collected in a cross-sectional design (Study 1) and in a longitudinal design with three assessment points (Study 2). Results of both studies supported the hypothesized mediational model. Specifically, social anxiety was inversely related to attentional control, which itself positively predicted positive affect. This mediation remained significant even when statistically controlling for the effects of depression. Additionally, the hypothesized model provided superior model fit to theoretically-grounded equivalent models in both studies. Implications of these findings for understanding diminished positive affect in social anxiety are discussed. PMID:23254261

  19. Arrangement of permanent magnet and reed switches for control rod position indicator of SMART CEDM

    International Nuclear Information System (INIS)

    Yoo, J. Y.; Kim, J. I.; Kim, J. H.; Hur, H.; Jang, M. H.

    2001-01-01

    The reliability and accuracy of the information on control rod position are very important to the reactor safety and the design of the core protection system. A survey on the RSPT(Reed Switch Position Transmitter) type control rod position indication system and its actual implementation in the exiting nuclear power plants in Korea was performed first. The control rod position indicator having the high performance for SMART was developed on the basis of RSPT technology identified through the survey. The arrangement of permanent magnet and reed switches is the most important procedure in the design of control rod position indication. In this study, the characteristics of permanent magnet and reed switches are introduced and the calculation method for arrangement of permanent magnet and reed switch is presented

  20. Design of magnetic flux concentrator of permancent magnet for control rod position indicator of SMART CEDM

    International Nuclear Information System (INIS)

    Yoo, J. Y.; Kim, J. H.; Hur, H.; Kim, J. I.

    2002-01-01

    The reliability and accuracy of the information on control rod position are very important to the reactor safety and the design of the core protection system. A survey on the RSPT(Reed Switch Position Transmitter) type control rod position indication system and its actual implementation in the exiting nuclear power plants in Korea was performed first. The control rod position indicator having the high performance for SMART was developed on the basis of RSPT technology identified through the survey. The arrangement of permanent magnet and reed switches is the most important procedure in the design of control rod position indication. In this study, the magnetic flux concentrator of permanent magnet is introduced and the calculation method for effective flux area for reed switch is presented

  1. Determination of the plasma position for its real-time control in the COMPASS tokamak

    International Nuclear Information System (INIS)

    Janky, F.; Havlicek, J.; Valcarcel, D.; Hron, M.; Horacek, J.; Kudlacek, O.; Panek, R.; Carvalho, B.B.

    2011-01-01

    An efficient horizontal and vertical stabilization of the plasma column position are essential for a reliable tokamak operation. Plasma position is generally determined by plasma current, plasma pressure and external vertical and horizontal magnetic fields. Such fields are generated by poloidal field coils and proper algorithm for the current control have to by applied, namely, in case of fast feedback loops. This paper presents a real-time plasma position reconstruction algorithms developed for the COMPASS tokamak. Further, its implementation in the MARTe (Multithreaded Application Real-Time executor) is described and the first results from test of the algorithm for real-time control of horizontal plasma positions are presented.

  2. Determination of the plasma position for its real-time control in the COMPASS tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Janky, F., E-mail: jankyf@ipp.cas.cz [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 182 00 Prague (Czech Republic); Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, CZ-18000 Prague (Czech Republic); Havlicek, J. [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 182 00 Prague (Czech Republic); Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, CZ-18000 Prague (Czech Republic); Valcarcel, D. [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P1049-001 Lisboa (Portugal); Hron, M.; Horacek, J. [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 182 00 Prague (Czech Republic); Kudlacek, O. [Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Technicka 2, 166 27 Prague (Czech Republic); Panek, R. [Institute of Plasma Physics, AS CR, v.v.i., Association EURATOM/IPP.CR, Za Slovankou 3, 182 00 Prague (Czech Republic); Carvalho, B.B. [Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, P1049-001 Lisboa (Portugal)

    2011-10-15

    An efficient horizontal and vertical stabilization of the plasma column position are essential for a reliable tokamak operation. Plasma position is generally determined by plasma current, plasma pressure and external vertical and horizontal magnetic fields. Such fields are generated by poloidal field coils and proper algorithm for the current control have to by applied, namely, in case of fast feedback loops. This paper presents a real-time plasma position reconstruction algorithms developed for the COMPASS tokamak. Further, its implementation in the MARTe (Multithreaded Application Real-Time executor) is described and the first results from test of the algorithm for real-time control of horizontal plasma positions are presented.

  3. Sensor-based automated docking of large waste canisters

    International Nuclear Information System (INIS)

    Drotning, W.D.

    1990-01-01

    Sensor-based programmable robots have the potential to speed up remote manipulation operations while protecting operators from exposure to radiation. Conventional master/slave manipulators have proven to be very slow in performing precision remote operations. In addition, inadvertent collisions of remotely manipulated objects with their environment increase the hazards associated with remote handling. This paper describes the development of a robotic system for the sensor-based automated remote manipulation and precision docking of large payloads. Computer vision and proximity sensing are used to control the precision docking of a large object with a passive target cavity. Specifically, a container of nuclear spent fuel on a transport vehicle is mated with an emplacement door on a vertical storage borehole at a waste repository

  4. Real-time horizontal position control for Aditya-upgrade tokamak

    International Nuclear Information System (INIS)

    Kumar, Rohit; Ghosh, Joydeep; Tanna, Rakesh L.

    2015-01-01

    Position of plasma column is required to be controlled in real time for improved operation of any tokamak. A PID based system for real-time horizontal plasma position control has been designed for Aditya Upgrade tokamak. Modelling of transfer functions of actuators, plasma and diagnostic system are carried out for ADITYA-U tokamak. The PID controller is optimized using MATLAB-SIMULINK for horizontal position control. Further feed-forward loop is implemented where disturbance due to density variation is suppressed, which results in improved performance as compared to conventional PID operation. In this paper the detailed design of the whole system for real time control of plasma horizontal position in Aditya Upgrade tokamak is presented. (author)

  5. Design and Preliminary Testing of the International Docking Adapter's Peripheral Docking Target

    Science.gov (United States)

    Foster, Christopher W.; Blaschak, Johnathan; Eldridge, Erin A.; Brazzel, Jack P.; Spehar, Peter T.

    2015-01-01

    The International Docking Adapter's Peripheral Docking Target (PDT) was designed to allow a docking spacecraft to judge its alignment relative to the docking system. The PDT was designed to be compatible with relative sensors using visible cameras, thermal imagers, or Light Detection and Ranging (LIDAR) technologies. The conceptual design team tested prototype designs and materials to determine the contrast requirements for the features. This paper will discuss the design of the PDT, the methodology and results of the tests, and the conclusions pertaining to PDT design that were drawn from testing.

  6. Why are most EU pigs tail docked?

    DEFF Research Database (Denmark)

    D'eath, R.B.; Niemi, J.K.; Vosough Ahmadi, B.

    2016-01-01

    To limit tail biting incidence, most pig producers in Europe tail dock their piglets. This is despite EU Council Directive 2008/120/EC banning routine tail docking and allowing it only as a last resort. The paper aims to understand what it takes to fulfil the intentions of the Directive...... by examining economic results of four management and housing scenarios, and by discussing their consequences for animal welfare in the light of legal and ethical considerations. The four scenarios compared are: ‘Standard Docked’, a conventional housing scenario with tail docking meeting the recommendations...... for Danish production (0.7 m2/pig); ‘Standard Undocked’, which is the same as ‘Standard Docked’ but with no tail docking, ‘Efficient Undocked’ and ‘Enhanced Undocked’, which have increased solid floor area (0.9 and 1.0 m2/pig, respectively) provision of loose manipulable materials (100 and 200 g/straw per...

  7. An Evaluation of Explicit Receptor Flexibility in Molecular Docking Using Molecular Dynamics and Torsion Angle Molecular Dynamics.

    Science.gov (United States)

    Armen, Roger S; Chen, Jianhan; Brooks, Charles L

    2009-10-13

    Incorporating receptor flexibility into molecular docking should improve results for flexible proteins. However, the incorporation of explicit all-atom flexibility with molecular dynamics for the entire protein chain may also introduce significant error and "noise" that could decrease docking accuracy and deteriorate the ability of a scoring function to rank native-like poses. We address this apparent paradox by comparing the success of several flexible receptor models in cross-docking and multiple receptor ensemble docking for p38α mitogen-activated protein (MAP) kinase. Explicit all-atom receptor flexibility has been incorporated into a CHARMM-based molecular docking method (CDOCKER) using both molecular dynamics (MD) and torsion angle molecular dynamics (TAMD) for the refinement of predicted protein-ligand binding geometries. These flexible receptor models have been evaluated, and the accuracy and efficiency of TAMD sampling is directly compared to MD sampling. Several flexible receptor models are compared, encompassing flexible side chains, flexible loops, multiple flexible backbone segments, and treatment of the entire chain as flexible. We find that although including side chain and some backbone flexibility is required for improved docking accuracy as expected, docking accuracy also diminishes as additional and unnecessary receptor flexibility is included into the conformational search space. Ensemble docking results demonstrate that including protein flexibility leads to to improved agreement with binding data for 227 active compounds. This comparison also demonstrates that a flexible receptor model enriches high affinity compound identification without significantly increasing the number of false positives from low affinity compounds.

  8. Hybrid Force and Position Control Strategy of Robonaut Performing Object Transfer Task

    Directory of Open Access Journals (Sweden)

    Chen Gang

    2018-01-01

    Full Text Available This paper proposes a coordinated hybrid force/position control strategy of robonaut performing object transfer operation. Firstly, the constraint relationships between robonaut and object are presented. Base on them, the unified dynamic model of the robonaut and object is established to design the hybrid force/position control method. The movement, the internal force and the external constraint force of the object are considered as the control targets of the control system. Finally, a MATLAB simulation of the robonaut performing object transfer task verifies the correctness and effectiveness of the proposed method. The results show that all the targets can be control accurately by using the method proposed in this paper. The presented control method can control both internal and external forces while maintaining control accuracy, which is a common control strategy.

  9. Demonstration of automated proximity and docking technologies

    Science.gov (United States)

    Anderson, Robert L.; Tsugawa, Roy K.; Bryan, Thomas C.

    An autodock was demonstrated using straightforward techniques and real sensor hardware. A simulation testbed was established and validated. The sensor design was refined with improved optical performance and image processing noise mitigation techniques, and the sensor is ready for production from off-the-shelf components. The autonomous spacecraft architecture is defined. The areas of sensors, docking hardware, propulsion, and avionics are included in the design. The Guidance Navigation and Control architecture and requirements are developed. Modular structures suitable for automated control are used. The spacecraft system manager functions including configuration, resource, and redundancy management are defined. The requirements for autonomous spacecraft executive are defined. High level decisionmaking, mission planning, and mission contingency recovery are a part of this. The next step is to do flight demonstrations. After the presentation the following question was asked. How do you define validation? There are two components to validation definition: software simulation with formal and vigorous validation, and hardware and facility performance validated with respect to software already validated against analytical profile.

  10. Design and reliability analysis of DP-3 dynamic positioning control architecture

    Science.gov (United States)

    Wang, Fang; Wan, Lei; Jiang, Da-Peng; Xu, Yu-Ru

    2011-12-01

    As the exploration and exploitation of oil and gas proliferate throughout deepwater area, the requirements on the reliability of dynamic positioning system become increasingly stringent. The control objective ensuring safety operation at deep water will not be met by a single controller for dynamic positioning. In order to increase the availability and reliability of dynamic positioning control system, the triple redundancy hardware and software control architectures were designed and developed according to the safe specifications of DP-3 classification notation for dynamically positioned ships and rigs. The hardware redundant configuration takes the form of triple-redundant hot standby configuration including three identical operator stations and three real-time control computers which connect each other through dual networks. The function of motion control and redundancy management of control computers were implemented by software on the real-time operating system VxWorks. The software realization of task loose synchronization, majority voting and fault detection were presented in details. A hierarchical software architecture was planed during the development of software, consisting of application layer, real-time layer and physical layer. The behavior of the DP-3 dynamic positioning control system was modeled by a Markov model to analyze its reliability. The effects of variation in parameters on the reliability measures were investigated. The time domain dynamic simulation was carried out on a deepwater drilling rig to prove the feasibility of the proposed control architecture.

  11. Dockomatic - automated ligand creation and docking.

    Science.gov (United States)

    Bullock, Casey W; Jacob, Reed B; McDougal, Owen M; Hampikian, Greg; Andersen, Tim

    2010-11-08

    The application of computational modeling to rationally design drugs and characterize macro biomolecular receptors has proven increasingly useful due to the accessibility of computing clusters and clouds. AutoDock is a well-known and powerful software program used to model ligand to receptor binding interactions. In its current version, AutoDock requires significant amounts of user time to setup and run jobs, and collect results. This paper presents DockoMatic, a user friendly Graphical User Interface (GUI) application that eases and automates the creation and management of AutoDock jobs for high throughput screening of ligand to receptor interactions. DockoMatic allows the user to invoke and manage AutoDock jobs on a single computer or cluster, including jobs for evaluating secondary ligand interactions. It also automates the process of collecting, summarizing, and viewing results. In addition, DockoMatic automates creation of peptide ligand .pdb files from strings of single-letter amino acid abbreviations. DockoMatic significantly reduces the complexity of managing multiple AutoDock jobs by facilitating ligand and AutoDock job creation and management.

  12. Dockomatic - automated ligand creation and docking

    Directory of Open Access Journals (Sweden)

    Hampikian Greg

    2010-11-01

    Full Text Available Abstract Background The application of computational modeling to rationally design drugs and characterize macro biomolecular receptors has proven increasingly useful due to the accessibility of computing clusters and clouds. AutoDock is a well-known and powerful software program used to model ligand to receptor binding interactions. In its current version, AutoDock requires significant amounts of user time to setup and run jobs, and collect results. This paper presents DockoMatic, a user friendly Graphical User Interface (GUI application that eases and automates the creation and management of AutoDock jobs for high throughput screening of ligand to receptor interactions. Results DockoMatic allows the user to invoke and manage AutoDock jobs on a single computer or cluster, including jobs for evaluating secondary ligand interactions. It also automates the process of collecting, summarizing, and viewing results. In addition, DockoMatic automates creation of peptide ligand .pdb files from strings of single-letter amino acid abbreviations. Conclusions DockoMatic significantly reduces the complexity of managing multiple AutoDock jobs by facilitating ligand and AutoDock job creation and management.

  13. Automated docking screens: a feasibility study.

    Science.gov (United States)

    Irwin, John J; Shoichet, Brian K; Mysinger, Michael M; Huang, Niu; Colizzi, Francesco; Wassam, Pascal; Cao, Yiqun

    2009-09-24

    Molecular docking is the most practical approach to leverage protein structure for ligand discovery, but the technique retains important liabilities that make it challenging to deploy on a large scale. We have therefore created an expert system, DOCK Blaster, to investigate the feasibility of full automation. The method requires a PDB code, sometimes with a ligand structure, and from that alone can launch a full screen of large libraries. A critical feature is self-assessment, which estimates the anticipated reliability of the automated screening results using pose fidelity and enrichment. Against common benchmarks, DOCK Blaster recapitulates the crystal ligand pose within 2 A rmsd 50-60% of the time; inferior to an expert, but respectrable. Half the time the ligand also ranked among the top 5% of 100 physically matched decoys chosen on the fly. Further tests were undertaken culminating in a study of 7755 eligible PDB structures. In 1398 cases, the redocked ligand ranked in the top 5% of 100 property-matched decoys while also posing within 2 A rmsd, suggesting that unsupervised prospective docking is viable. DOCK Blaster is available at http://blaster.docking.org .

  14. FRF based position controller design through system identification for A hydraulic cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hyoung Kyu; Kim, Dong Hwan [Dept. of Mechanical Design and Robot Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of); Park, Jong Won [Reliability Assessment Center, Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2015-11-15

    In this study, we have focused on the design of a controller and an operating program for the operation of the hydraulic actuators used in a shaker. To control the motion of the shaker accurately, the position of each hydraulic cylinder should be controlled precisely even under an uncertain environment. For this purpose, we have suggested a control algorithm using an FRF (frequency response function) based control which senses the behavior of the actuator in advance, calculates a transfer function through the system identification method, and provides the final control input. The experimental results on the performance of this system were compared with that of a simple PID control algorithm.

  15. Novel electro-hydraulic position control system for primary mirror supporting system

    Directory of Open Access Journals (Sweden)

    Xiongbin Peng

    2016-05-01

    Full Text Available In the field of modern large-scale telescope, primary mirror supporting system technology faces the difficulties of theoretically uniform output force request and bias compensation. Therefore, a novel position control system combining hydraulic system with servo motor system is introduced. The novel system ensures uniform output force on supporting points without complicating the mechanical structure. The structures of both primary mirror supporting system and novel position system are described. Then, the mathematical model of novel position control system is derived for controller selection. A proportional–derivative controller is adopted for simulations and experiments of step response and triangle path tracking. The results show that proportional–derivative controller guarantees the system with micrometer-level positioning ability. A modified proportional–derivative controller is utilized to promote system behavior with faster response overshoot. The novel position control system is then applied on primary mirror supporting system. Coupling effect is observed among actuator partitions, and relocation of virtual pivot supporting point is chosen as the decoupling measurement. The position keeping ability of the primary mirror supporting system is verified by rotating the mirror cell at a considerably high rate. The experiment results show that the decoupled system performs better with smaller bias and shorter recovery time.

  16. FlexAID: Revisiting Docking on Non-Native-Complex Structures.

    Science.gov (United States)

    Gaudreault, Francis; Najmanovich, Rafael J

    2015-07-27

    Small-molecule protein docking is an essential tool in drug design and to understand molecular recognition. In the present work we introduce FlexAID, a small-molecule docking algorithm that accounts for target side-chain flexibility and utilizes a soft scoring function, i.e. one that is not highly dependent on specific geometric criteria, based on surface complementarity. The pairwise energy parameters were derived from a large dataset of true positive poses and negative decoys from the PDBbind database through an iterative process using Monte Carlo simulations. The prediction of binding poses is tested using the widely used Astex dataset as well as the HAP2 dataset, while performance in virtual screening is evaluated using a subset of the DUD dataset. We compare FlexAID to AutoDock Vina, FlexX, and rDock in an extensive number of scenarios to understand the strengths and limitations of the different programs as well as to reported results for Glide, GOLD, and DOCK6 where applicable. The most relevant among these scenarios is that of docking on flexible non-native-complex structures where as is the case in reality, the target conformation in the bound form is not known a priori. We demonstrate that FlexAID, unlike other programs, is robust against increasing structural variability. FlexAID obtains equivalent sampling success as GOLD and performs better than AutoDock Vina or FlexX in all scenarios against non-native-complex structures. FlexAID is better than rDock when there is at least one critical side-chain movement required upon ligand binding. In virtual screening, FlexAID results are lower on average than those of AutoDock Vina and rDock. The higher accuracy in flexible targets where critical movements are required, intuitive PyMOL-integrated graphical user interface and free source code as well as precompiled executables for Windows, Linux, and Mac OS make FlexAID a welcome addition to the arsenal of existing small-molecule protein docking methods.

  17. Quantum dots for future nanophotonic devices : lateral ordering, position, and number control

    NARCIS (Netherlands)

    Nötzel, R.; Sritirawisarn, N.; Selçuk, E.; Wang, H.; Yuan, J.

    2009-01-01

    We review our recent advances in the lateral ordering, position, and number control of self-organized epitaxial semiconductor quantum dots based on self-organized anisotropic strain engineering, growth on patterned substrates, and selective area growth.

  18. Railway cognitive radio to enhance safety, security, and performance of positive train control.

    Science.gov (United States)

    2013-02-01

    Robust and interoperable wireless communications are vital to Positive Train Control (PTC). The railway industry has started adopting software-defined radios (SDRs) for packet-data transmission. SDR systems realize previously fixed components as reco...

  19. Precision position control of servo systems using adaptive back-stepping and recurrent fuzzy neural networks

    International Nuclear Information System (INIS)

    Kim, Han Me; Kim, Jong Shik; Han, Seong Ik

    2009-01-01

    To improve position tracking performance of servo systems, a position tracking control using adaptive back-stepping control(ABSC) scheme and recurrent fuzzy neural networks(RFNN) is proposed. An adaptive rule of the ABSC based on system dynamics and dynamic friction model is also suggested to compensate nonlinear dynamic friction characteristics. However, it is difficult to reduce the position tracking error of servo systems by using only the ABSC scheme because of the system uncertainties which cannot be exactly identified during the modeling of servo systems. Therefore, in order to overcome system uncertainties and then to improve position tracking performance of servo systems, the RFNN technique is additionally applied to the servo system. The feasibility of the proposed control scheme for a servo system is validated through experiments. Experimental results show that the servo system with ABS controller based on the dual friction observer and RFNN including the reconstruction error estimator can achieve desired tracking performance and robustness

  20. Integrated shell approach to vertical position control on PBX-M

    International Nuclear Information System (INIS)

    Hatcher, R.E.; Okabayashi, M.

    1995-03-01

    The PBX-M device produces highly shaped discharges that, because of the negative external magnetic field decay index required, are vertically unstable. Vertical positional stability in PBX-M has been achieved by directly controlling the n = 0 component of the eddy current in the passive shell instead of the commonly used function of magnetic flux signals. Because the active coil is controlled via currents in the passive shell we call this an ''integrated shell'' approach to vertical position control. We present results of these experiments and make comparisons between the two methods of control

  1. Control rod position fault diagnosis and its software realization of pressurized water reactor

    International Nuclear Information System (INIS)

    Chang Zhengke; Shao Dinghong

    2004-11-01

    PLC software is adopted in the Rod Position Monitoring System of QS2NPS. By this software, the position of control rods can be monitored in real time, the abnormal phenomena can be identified immediately, the correctness and timeliness of fault diagnosis are improved remarkably. the identification and recordance of rod position fault, the performance validation of measure channel are realized also. The function and effect of this software are introduced. (authors)

  2. Dissociable influences of reward motivation and positive emotion on cognitive control.

    Science.gov (United States)

    Chiew, Kimberly S; Braver, Todd S

    2014-06-01

    It is becoming increasingly appreciated that affective and/or motivational influences contribute strongly to goal-oriented cognition and behavior. An unresolved question is whether emotional manipulations (i.e., direct induction of affectively valenced subjective experience) and motivational manipulations (e.g., delivery of performance-contingent rewards and punishments) have similar or distinct effects on cognitive control. Prior work has suggested that reward motivation can reliably enhance a proactive mode of cognitive control, whereas other evidence is suggestive that positive emotion improves cognitive flexibility, but reduces proactive control. However, a limitation of the prior research is that reward motivation and positive emotion have largely been studied independently. Here, we directly compared the effects of positive emotion and reward motivation on cognitive control with a tightly matched, within-subjects design, using the AX-continuous performance task paradigm, which allows for relative measurement of proactive versus reactive cognitive control. High-resolution pupillometry was employed as a secondary measure of cognitive dynamics during task performance. Robust increases in behavioral and pupillometric indices of proactive control were observed with reward motivation. The effects of positive emotion were much weaker, but if anything, also reflected enhancement of proactive control, a pattern that diverges from some prior findings. These results indicate that reward motivation has robust influences on cognitive control, while also highlighting the complexity and heterogeneity of positive-emotion effects. The findings are discussed in terms of potential neurobiological mechanisms.

  3. Control of spool position of on/off solenoid operated hydraulic valve by sliding-mode controller

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Hak; Hong, Hyun Wook; Park, Myeong Kwan [Pusan National University, Busan (Korea, Republic of); Yun, Young Won [KHPS, Busan (Korea, Republic of)

    2015-11-15

    The use of on/off solenoid operated hydraulic valves instead of proportional valves has been attracting the interest of many researchers and engineers. However, there exist difficulties in controlling the on/off valve because of highly nonlinear characteristics including hysteresis and saturation. This paper considers the application of on/off solenoid operated hydraulic valves to control position of a hydraulic cylinder with the aim of evaluating, feasibility and practicability of their implementation and understanding the potential benefits when they are used in existing hydraulic systems. Assuming that only the current is measured, a sliding mode observer is designed to estimate the spool position and velocity. To alleviate the aforementioned difficulties in controlling the spool position, a nonlinear observer-based controller of an on/off solenoid valve is designed, taking into account the estimated values, based on a nonlinear model including hysteresis and saturation. The control objective is to track a desired spool trajectory. Simulation and experimental results illustrate the efficiency of the designed controller. The proposed controller is validated again in a single-rod hydraulic actuator. Experimental results show that the fluid flow through the valve orifice by controlling the spool position was successfully controlled.

  4. Development of a mcirocontroller to the positioning control of an ionization chamber

    International Nuclear Information System (INIS)

    Manfrini, Francisco A.L.; Rocha, Cristina S.C.; Reis, Renato J.; Oliveira, Arno Heeren de

    2007-01-01

    It was developed a microcontroller to positioning of ionization chamber with high precision. Considering the high sensitivity of intensity of radiation with the distance source-detector is necessary to develop an eletronics able to control position the detector with high precision. The project was based on microcontroller AT 89S8252 of Atmel company. (author)

  5. Practical controller design for ultra-precision positioning of stages with a pneumatic artificial muscle actuator

    Science.gov (United States)

    Tang, T. F.; Chong, S. H.

    2017-06-01

    This paper presents a practical controller design method for ultra-precision positioning of pneumatic artificial muscle actuator stages. Pneumatic artificial muscle (PAM) actuators are safe to use and have numerous advantages which have brought these actuators to wide applications. However, PAM exhibits strong non-linear characteristics, and these limitations lead to low controllability and limit its application. In practice, the non-linear characteristics of PAM mechanism are difficult to be precisely modeled, and time consuming to model them accurately. The purpose of the present study is to clarify a practical controller design method that emphasizes a simple design procedure that does not acquire plants parameters modeling, and yet is able to demonstrate ultra-precision positioning performance for a PAM driven stage. The practical control approach adopts continuous motion nominal characteristic trajectory following (CM NCTF) control as the feedback controller. The constructed PAM driven stage is in low damping characteristic and causes severe residual vibration that deteriorates motion accuracy of the system. Therefore, the idea to increase the damping characteristic by having an acceleration feedback compensation to the plant has been proposed. The effectiveness of the proposed controller was verified experimentally and compared with a classical PI controller in point-to-point motion. The experiment results proved that the CM NCTF controller demonstrates better positioning performance in smaller motion error than the PI controller. Overall, the CM NCTF controller has successfully to reduce motion error to 3µm, which is 88.7% smaller than the PI controller.

  6. Sensory systems for a control rod position using reed switches for the integral reactor

    International Nuclear Information System (INIS)

    Yu, J. Y.; Choi, S.; Kim, J. H.; Lee, D. J.

    2007-01-01

    The system-integrated modular advanced reactor (SMART) currently under development at the Korea Atomic Energy Research Institute is being designed with a soluble boron free operation and the use of nuclear heating for the reactor start-up. These design features require a Control Element Drive Mechanism (CEDM) for the SMART to have a fine-step movement capability as well as a high reliability for a fine reactivity control. Also the reliability and accuracy of the information for the control rod position is very important to the reactor safety as well as the design of the core protection system. The position indicator is classified as a Class 1E component because the rod position signal of the position indicator is used in the safety related systems. Therefore it will be separated from the control systems to the extent that a failure of any single control system component of a channel and shall have sufficient independence, redundancy, and testability to perform its safety functions assuming a single failure. The position indicator is composed of a permanent magnet, reed switches and a voltage divider. Four independent position indicators around the upper pressure housing provide an indication of the position of a control rod comprising of a permanent magnet with a magnetic field concentrator which moves with the extension shaft connected to the control rod. The zigzag arranged reed switches are positioned along a line parallel to the path of the movement of the permanent magnet and it is activated selectively when the permanent magnet passes by. A voltage divider electrically connected to the reed switches provides a signal commensurate with the position of the control rod. The signal may then be transmitted to a position indicating device. In order to monitor the operating condition of the rotary step motor of CEDM, the angular position detector was installed at the top of the rotary step motor by means of connecting between the planetary gear and the rotating

  7. Positive control for cytotoxicity evaluation of dental vinyl polysiloxane impression materials using sodium lauryl sulfate.

    Science.gov (United States)

    Kwon, Jae-Sung; Lee, Sang-Bae; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-11-01

    Vinyl polysiloxane (VPS) is elastomeric dental impression material which, despite having very few reports of adverse reactions, has shown high levels of cytotoxicity that is difficult to be interpreted without referencing to the positive control material. Therefore, in this study, positive control VPS was developed using sodium lauryl sulfate (SLS) for the reference of cytotoxicity test. The positive control VPS with SLS was formed with a different proportion of SLS (0, 1, 2, 4, 8 and 16 wt%) added to the base. The cytotoxicity test was then carried out using the extractions or dilutions of the extractions from each of the test samples using murine fibroblast cells (L929). The final product of positive control VPS behaved similar to commercially available VPS; being initially liquid-like and then becoming rubber-like. Ion chromatography showed that the level of SLS released from the product increased as the proportion of added SLS increased, consequently resulting in an increased level of cytotoxicity. Also, the commercially available VPS was less cytotoxic than the positive control VPS with more or equal to 2 wt% of SLS. However, even the VPS with the highest SLS (16 wt%) did not cause oral mucosa irritation during the animal study. The positive control VPS was successfully produced using SLS, which will be useful in terms of providing references during in vitro cytotoxicity testing.

  8. Performance estimation of control rod position indicator due to aging of magnet

    International Nuclear Information System (INIS)

    Yu, Je Yong; Kim, Ji Ho; Huh, Hyung; Choi, Myoung Hwan; Sohn, Dong Seong

    2009-01-01

    The Control Element Drive Mechanism (CEDM) for the integral reactor is designed to raise and lower the control rod in steps of 2mm in order to satisfy the design features of the integral reactor which are the soluble boron free operation and the use of a nuclear heating for the reactor start-up. The actual position of the control rod could be achieved to sense the magnet connected to the control rod by the position indicator around the upper pressure housing of CEDM. It is sufficient that the actual position information of control rod at 20mm interval from the position indicator is used for the core safety analysis. As the magnet moves upward along the position indicator assembly from the bottom to the top in the upper pressure housing, the output voltage increases linearly step-wise at 0.2VDC increments. Between every step there are transient areas which occur by a contact closing of three reed switches which is the 2-3-2 contact closing sequence. In this paper the output voltage signal corresponding to the position of control rod was estimated on the 2-1-2 contact closing sequence due to the aging of the magnet.

  9. Design and analysis of plasma position and shape control in superconducting tokamak JT-60SC

    Energy Technology Data Exchange (ETDEWEB)

    Matsukawa, M. E-mail: matsukaw@naka.jaeri.go.jp; Ishida, S.; Sakasai, A.; Urata, K.; Senda, I.; Kurita, G.; Tamai, H.; Sakurai, S.; Miura, Y.M.; Masaki, K.; Shimada, K.; Terakado, T

    2003-09-01

    The analyses of the plasma position and shape control in the superconducting tokamak JT-60SC in JAERI are presented. The vacuum vessel and stabilizing plates located closely to the plasma are modeled in 3 dimension, and we can take into account the large ports in the vacuum vessel. The linear numerical model used in the design for the plasma feedback control system is based on Grad-Shafranov equation, which allows the plasma surface deformation. For a slower control of the plasma shape, the superconducting equilibrium field (EF) coils outside toroidal field coils are used, while for a fast control of the plasma position, in-vessel normal conducting coils (IV coil) are used. It is shown that the available loop voltages of the EF and IV coils are very limited, but there are sufficient accuracy and acceptable response time of plasma position and shape control.

  10. Design and analysis of plasma position and shape control in superconducting tokamak JT-60SC

    International Nuclear Information System (INIS)

    Matsukawa, M.; Ishida, S.; Sakasai, A.; Urata, K.; Senda, I.; Kurita, G.; Tamai, H.; Sakurai, S.; Miura, Y.M.; Masaki, K.; Shimada, K.; Terakado, T.

    2003-01-01

    The analyses of the plasma position and shape control in the superconducting tokamak JT-60SC in JAERI are presented. The vacuum vessel and stabilizing plates located closely to the plasma are modeled in 3 dimension, and we can take into account the large ports in the vacuum vessel. The linear numerical model used in the design for the plasma feedback control system is based on Grad-Shafranov equation, which allows the plasma surface deformation. For a slower control of the plasma shape, the superconducting equilibrium field (EF) coils outside toroidal field coils are used, while for a fast control of the plasma position, in-vessel normal conducting coils (IV coil) are used. It is shown that the available loop voltages of the EF and IV coils are very limited, but there are sufficient accuracy and acceptable response time of plasma position and shape control

  11. Pneumatic Rotary Actuator Position Servo System Based on ADE-PD Control

    Directory of Open Access Journals (Sweden)

    Yeming Zhang

    2018-03-01

    Full Text Available In order to accurately control the rotation position of a pneumatic rotary actuator, the flow state of the gas and the motion state of the pneumatic rotary actuator in the pneumatic rotary actuator position servo system are analyzed in this paper. The mathematical model of the system and the experiment platform are established after that. An Adaptive Differential Evolution (ADE algorithm which adaptively ameliorates the scaling factor and crossover probability in the process of individual evolution is proposed and applied to the parameter optimization of PD controller. The experimental platform is used to compare the controller with Differential Evolution (DE algorithm and NCD-PID controller. Finally, the characteristics of the system are tested by increasing the inertial load. The experimental results illustrate that system using ADE-PD control strategy has greater position precision and faster response than using DE-PD and NCD-PID strategies, and shows great robustness.

  12. Research of Control Strategy in the Large Electric Cylinder Position Servo System

    Directory of Open Access Journals (Sweden)

    Yongguang Liu

    2015-01-01

    Full Text Available An ideal positioning response is very difficult to realize in the large electric cylinder system that is applied in missile launcher because of the presence of many nonlinear factors such as load disturbance, parameter variations, lost motion, and friction. This paper presents a piecewise control strategy based on the optimized positioning principle. The combined application of position interpolation method and modified incremental PID with dead band is proposed and applied into control system. The experimental result confirms that this combined control strategy is not only simple to be applied into high accuracy real-time control system but also significantly improves dynamic response, steady accuracy, and anti-interference performance, which has very important significance to improve the smooth control of the large electric cylinder.

  13. Nonlinear control of marine vehicles using only position and attitude measurements

    Energy Technology Data Exchange (ETDEWEB)

    Paulsen, Marit Johanne

    1996-12-31

    This thesis presents new results on the design and analysis of nonlinear output feedback controllers for auto pilots and dynamic positioning systems for ships and underwater vehicles. Only position and attitude measurements of the vehicle are used in the control design. The underlying idea of the work is to use certain structural properties of the equations of motion in the controller design and analysis. New controllers for regulation and tracking have been developed and the stability of the resulting closed-loop systems has been rigorously established. The results are supported by simulations. The following problems have been investigated covering design of passive controller for regulation, comparison of two auto pilots, nonlinear damping compensation for tracking, tracking control for nonlinear ships, and output tracking control with wave filtering for multivariable models of possibly unstable vehicles. 97 refs., 32 figs.

  14. Simultaneous positioning and orientation of a single nano-object by flow control: theory and simulations

    International Nuclear Information System (INIS)

    Mathai, Pramod P; Berglund, Andrew J; Alexander Liddle, J; Shapiro, Benjamin A

    2011-01-01

    In this paper, we theoretically describe a method to simultaneously control both the position and orientation of single nano-objects in fluids by precisely controlling the flow around them. We develop and simulate a control law that uses electro-osmotic flow (EOF) actuation to translate and rotate rigid nano-objects in two spatial dimensions. Using EOF to control nano-objects offers advantages as compared to other approaches: a wide class of objects can be manipulated (no magnetic or electric dipole moments are needed), the object can be controlled over a long range (>100 μm) with sub-micrometer accuracy, and control may be achieved with simple polydimethylsiloxane (PDMS) devices. We demonstrate the theory and numerical solutions that will enable deterministic control of the position and orientation of a nano-object in solution, which can be used, for example, to integrate nanostructures in circuits and orient sensors to probe living cells.

  15. Virtual reality simulation of fuzzy-logic control during underwater dynamic positioning

    Science.gov (United States)

    Thekkedan, Midhin Das; Chin, Cheng Siong; Woo, Wai Lok

    2015-03-01

    In this paper, graphical-user-interface (GUI) software for simulation and fuzzy-logic control of a remotely operated vehicle (ROV) using MATLAB™ GUI Designing Environment is proposed. The proposed ROV's GUI platform allows the controller such as fuzzy-logic control systems design to be compared with other controllers such as proportional-integral-derivative (PID) and sliding-mode controller (SMC) systematically and interactively. External disturbance such as sea current can be added to improve the modelling in actual underwater environment. The simulated results showed the position responses of the fuzzy-logic control exhibit reasonable performance under the sea current disturbance.

  16. Self-tuning control studies of the plasma vertical position problem

    International Nuclear Information System (INIS)

    Zheng, Guang Lin; Wellstead, P.E.; Browne, M.L.

    1993-01-01

    The plasma vertical position system in a tokamak device can be open-loop unstable with time-varying dynamics, such that the instability increases with system dynamical changes. Time-varying unstable dynamics makes the plasma vertical position a particularly difficult one to control with traditional fixed-coefficient controllers. A self-tuning technique offers a new solution of the plasma vertical position control problem by an adaptive control approach. Specifically, the self-tuning controller automatically tunes the controller parameters without an a priori knowledge of the system dynamics and continuously tracks dynamical changes within the system, thereby providing the system with auto-tuning and adaptive tuning capabilities. An overview of the self-tuning methods is given, and their applicability to a simulation of the Joint European Torus (JET) vertical plasma positions system is illustrated. Specifically, the applicability of pole-assignment and generalized predictive control self-tuning methods to the vertical plasma position system is demonstrated. 26 refs., 16 figs., 1 tab

  17. Scheduling Trucks in a Cross-Dock with Mixed Service Mode Dock Doors

    DEFF Research Database (Denmark)

    Bodnar, Peter; Azadeh, Kaveh; Koster, René de

    2017-01-01

    The problem considered in this paper is how to schedule inbound and outbound trucks subject to time windows at a multidoor cross-dock. Dock doors can either be dedicated to inbound or outbound trucks or be capable of handling both truck types. In addition, loads are allowed to be temporarily...

  18. Magnetic sensorless control of plasma position and shape in a tokamak

    International Nuclear Information System (INIS)

    Nakamura, K.; Luo, J.R.; Wang, H.Z.

    2005-01-01

    Magnetic sensorless sensing and control experiments of the plasma horizontal position have been carried out in the superconducting tokamak HT-7. The sensing is made focusing on the ripple frequency component of the power supply with thyristor and directly from them without time integration. There is no drift problem of integrator of magnetic sensors. Two kinds of control experiments were carried out, to keep the position constant and swing the position in a triangular waveform. And magnetic sensorless sensing of plasma shape is discussed. (author)

  19. Protein-protein docking with F(2Dock 2.0 and GB-rerank.

    Directory of Open Access Journals (Sweden)

    Rezaul Chowdhury

    Full Text Available Computational simulation of protein-protein docking can expedite the process of molecular modeling and drug discovery. This paper reports on our new F(2 Dock protocol which improves the state of the art in initial stage rigid body exhaustive docking search, scoring and ranking by introducing improvements in the shape-complementarity and electrostatics affinity functions, a new knowledge-based interface propensity term with FFT formulation, a set of novel knowledge-based filters and finally a solvation energy (GBSA based reranking technique. Our algorithms are based on highly efficient data structures including the dynamic packing grids and octrees which significantly speed up the computations and also provide guaranteed bounds on approximation error.The improved affinity functions show superior performance compared to their traditional counterparts in finding correct docking poses at higher ranks. We found that the new filters and the GBSA based reranking individually and in combination significantly improve the accuracy of docking predictions with only minor increase in computation time. We compared F(2 Dock 2.0 with ZDock 3.0.2 and found improvements over it, specifically among 176 complexes in ZLab Benchmark 4.0, F(2 Dock 2.0 finds a near-native solution as the top prediction for 22 complexes; where ZDock 3.0.2 does so for 13 complexes. F(2 Dock 2.0 finds a near-native solution within the top 1000 predictions for 106 complexes as opposed to 104 complexes for ZDock 3.0.2. However, there are 17 and 15 complexes where F(2 Dock 2.0 finds a solution but ZDock 3.0.2 does not and vice versa; which indicates that the two docking protocols can also complement each other.The docking protocol has been implemented as a server with a graphical client (TexMol which allows the user to manage multiple docking jobs, and visualize the docked poses and interfaces. Both the server and client are available for download. Server: http

  20. Protein-Protein Docking with F2Dock 2.0 and GB-Rerank

    Science.gov (United States)

    Chowdhury, Rezaul; Rasheed, Muhibur; Keidel, Donald; Moussalem, Maysam; Olson, Arthur; Sanner, Michel; Bajaj, Chandrajit

    2013-01-01

    Motivation Computational simulation of protein-protein docking can expedite the process of molecular modeling and drug discovery. This paper reports on our new F2 Dock protocol which improves the state of the art in initial stage rigid body exhaustive docking search, scoring and ranking by introducing improvements in the shape-complementarity and electrostatics affinity functions, a new knowledge-based interface propensity term with FFT formulation, a set of novel knowledge-based filters and finally a solvation energy (GBSA) based reranking technique. Our algorithms are based on highly efficient data structures including the dynamic packing grids and octrees which significantly speed up the computations and also provide guaranteed bounds on approximation error. Results The improved affinity functions show superior performance compared to their traditional counterparts in finding correct docking poses at higher ranks. We found that the new filters and the GBSA based reranking individually and in combination significantly improve the accuracy of docking predictions with only minor increase in computation time. We compared F2 Dock 2.0 with ZDock 3.0.2 and found improvements over it, specifically among 176 complexes in ZLab Benchmark 4.0, F2 Dock 2.0 finds a near-native solution as the top prediction for 22 complexes; where ZDock 3.0.2 does so for 13 complexes. F2 Dock 2.0 finds a near-native solution within the top 1000 predictions for 106 complexes as opposed to 104 complexes for ZDock 3.0.2. However, there are 17 and 15 complexes where F2 Dock 2.0 finds a solution but ZDock 3.0.2 does not and vice versa; which indicates that the two docking protocols can also complement each other. Availability The docking protocol has been implemented as a server with a graphical client (TexMol) which allows the user to manage multiple docking jobs, and visualize the docked poses and interfaces. Both the server and client are available for download. Server: http

  1. DockQ: A Quality Measure for Protein-Protein Docking Models.

    Directory of Open Access Journals (Sweden)

    Sankar Basu

    Full Text Available The state-of-the-art to assess the structural quality of docking models is currently based on three related yet independent quality measures: Fnat, LRMS, and iRMS as proposed and standardized by CAPRI. These quality measures quantify different aspects of the quality of a particular docking model and need to be viewed together to reveal the true quality, e.g. a model with relatively poor LRMS (>10Å might still qualify as 'acceptable' with a descent Fnat (>0.50 and iRMS (<3.0Å. This is also the reason why the so called CAPRI criteria for assessing the quality of docking models is defined by applying various ad-hoc cutoffs on these measures to classify a docking model into the four classes: Incorrect, Acceptable, Medium, or High quality. This classification has been useful in CAPRI, but since models are grouped in only four bins it is also rather limiting, making it difficult to rank models, correlate with scoring functions or use it as target function in machine learning algorithms. Here, we present DockQ, a continuous protein-protein docking model quality measure derived by combining Fnat, LRMS, and iRMS to a single score in the range [0, 1] that can be used to assess the quality of protein docking models. By using DockQ on CAPRI models it is possible to almost completely reproduce the original CAPRI classification into Incorrect, Acceptable, Medium and High quality. An average PPV of 94% at 90% Recall demonstrating that there is no need to apply predefined ad-hoc cutoffs to classify docking models. Since DockQ recapitulates the CAPRI classification almost perfectly, it can be viewed as a higher resolution version of the CAPRI classification, making it possible to estimate model quality in a more quantitative way using Z-scores or sum of top ranked models, which has been so valuable for the CASP community. The possibility to directly correlate a quality measure to a scoring function has been crucial for the development of scoring functions for

  2. A Position Sensorless Control Method for SRM Based on Variation of Phase Inductance

    Science.gov (United States)

    Komatsuzaki, Akitomo; Miki, Ichiro

    Switched reluctance motor (SRM) drives are suitable for variable speed industrial applications because of the simple structure and high-speed capability. However, it is necessary to detect the rotor position with a position sensor attached to the motor shaft. The use of the sensor increases the cost of the drive system and machine size, and furthermore the reliability of the system is reduced. Therefore, several approaches to eliminate the position sensor have already been reported. In this paper, a position sensorless control method based on the variation of the phase inductance is described. The phase inductance regularly varies with the rotor position. The SRM is controlled without the position sensor using the de-fluxing period and the phase inductance. The turn-off timing is determined by computing the difference of angle between the sampling point and the aligned point and the variation of angle during the de-fluxing period. In the magnetic saturation region, the phase inductance at the current when the effect of the saturation starts is computed and the sensorless control can be carried out using this inductance. Experimental results show that the SRM is well controlled without the position sensor using the proposed method.

  3. Maternal sensitivity and latency to positive emotion following challenge: pathways through effortful control.

    Science.gov (United States)

    Conway, Anne; McDonough, Susan C; Mackenzie, Michael; Miller, Alison; Dayton, Carolyn; Rosenblum, Katherine; Muzik, Maria; Sameroff, Arnold

    2014-01-01

    The ability to self-generate positive emotions is an important component of emotion regulation. In this study, we focus on children's latency to express positive emotions following challenging situations and assess whether this ability operates through early maternal sensitivity and children's effortful control. Longitudinal relations between maternal sensitivity, infant negative affect, effortful control, and latency to positive emotion following challenge were examined in 156 children who were 33 months of age. Structural equation models supported the hypothesis that maternal sensitivity during infancy predicted better effortful control and, in turn, shorter latencies to positive emotions following challenge at 33 months. Directions for future research are discussed. © 2014 Michigan Association for Infant Mental Health.

  4. Friction-resilient position control for machine tools—Adaptive and sliding-mode methods compared

    DEFF Research Database (Denmark)

    Papageorgiou, Dimitrios; Blanke, Mogens; Niemann, Hans Henrik

    2018-01-01

    Robust trajectory tracking and increasing demand for high-accuracy tool positioning have motivated research in advanced control design for machine tools. State-of-the-art industry solutions employ cascades of Proportional (P) and Proportional-Integral (PI) controllers for closed-loop servo contro...

  5. Imagined Positive Emotions and Inhibitory Control: The Differentiated Effect of Pride versus Happiness

    Science.gov (United States)

    Katzir, Maayan; Eyal, Tal; Meiran, Nachshon; Kessler, Yoav

    2010-01-01

    "Inhibitory control" is a cognitive mechanism that contributes to successful self-control (i.e., adherence to a long-term goal in the face of an interfering short-term goal). This research explored the effect of imagined positive emotional events on inhibition. The authors proposed that the influence of imagined emotions on inhibition…

  6. Real-time digital control of plasma position and shape on the TEXTOR tokamak

    International Nuclear Information System (INIS)

    Mitri, Mikhael

    2009-01-01

    Beside the objective of contributing to the controlled thermonuclear fusion research and ultimately the development of a fusion based power plant, the main objectives of the thesis are a substantial improvement of plasma vertical position control and plasma shape control as well as a better understanding of formerly unexplained effects, e.g. disturbance fields. As for the vertical position control, a deep analysis has to be undertaken to identify the problem sources. Accurate control of the plasma position is very difficult to achieve. This is mainly due to the complexity of the tokamak and the difficulty in measuring or modelling all relevant discharge variables. Any models would be highly nonlinear and time varying. Thus, for simulation and controller design, a simplified, but nevertheless accurate model has to be developed, based on physics and measured data of the process. Furthermore, the quality of the measured position has to be improved by using new inductive sensors, integrators, and hardware. The integration drift problem has to be analysed and resolved by developing a drift-free integration method. Concerning the shape control, a better understanding of the relation between the stray fields and the iron core saturation is required. Furthermore, the influence on the plasma elongation has to be determined. Upon this, a shape compensation algorithm has to be developed accordingly. The accuracy of the shape control has to be better than 1%. (orig.)

  7. 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.

  8. Anticipatory planning and control of grasp positions and forces for dexterous two-digit manipulation.

    Science.gov (United States)

    Fu, Qiushi; Zhang, Wei; Santello, Marco

    2010-07-07

    Dexterous object manipulation requires anticipatory control of digit positions and forces. Despite extensive studies on sensorimotor learning of digit forces, how humans learn to coordinate digit positions and forces has never been addressed. Furthermore, the functional role of anticipatory modulation of digit placement to object properties remains to be investigated. We addressed these questions by asking human subjects (12 females, 12 males) to grasp and lift an inverted T-shaped object using precision grip at constrained or self-chosen locations. The task requirement was to minimize object roll during lift. When digit position was not constrained, subjects could have implemented many equally valid digit position-force coordination patterns. However, choice of digit placement might also have resulted in large trial-to-trial variability of digit position, hence challenging the extent to which the CNS could have relied on sensorimotor memories for anticipatory control of digit forces. We hypothesized that subjects would modulate digit placement for optimal force distribution and digit forces as a function of variable digit positions. All subjects learned to minimize object roll within the first three trials, and the unconstrained device was associated with significantly smaller grip forces but larger variability of digit positions. Importantly, however, digit load force modulation compensated for position variability, thus ensuring consistent object roll minimization on each trial. This indicates that subjects learned object manipulation by integrating sensorimotor memories with sensory feedback about digit positions. These results are discussed in the context of motor equivalence and sensorimotor integration of grasp kinematics and kinetics.

  9. DockQ: A Quality Measure for Protein-Protein Docking Models

    Science.gov (United States)

    Basu, Sankar

    2016-01-01

    The state-of-the-art to assess the structural quality of docking models is currently based on three related yet independent quality measures: Fnat, LRMS, and iRMS as proposed and standardized by CAPRI. These quality measures quantify different aspects of the quality of a particular docking model and need to be viewed together to reveal the true quality, e.g. a model with relatively poor LRMS (>10Å) might still qualify as 'acceptable' with a descent Fnat (>0.50) and iRMS (iRMS to a single score in the range [0, 1] that can be used to assess the quality of protein docking models. By using DockQ on CAPRI models it is possible to almost completely reproduce the original CAPRI classification into Incorrect, Acceptable, Medium and High quality. An average PPV of 94% at 90% Recall demonstrating that there is no need to apply predefined ad-hoc cutoffs to classify docking models. Since DockQ recapitulates the CAPRI classification almost perfectly, it can be viewed as a higher resolution version of the CAPRI classification, making it possible to estimate model quality in a more quantitative way using Z-scores or sum of top ranked models, which has been so valuable for the CASP community. The possibility to directly correlate a quality measure to a scoring function has been crucial for the development of scoring functions for protein structure prediction, and DockQ should be useful in a similar development in the protein docking field. DockQ is available at http://github.com/bjornwallner/DockQ/ PMID:27560519

  10. Critical element study on autonomous position control of articulated-arm type manipulator

    International Nuclear Information System (INIS)

    Oka, Kiyoshi; Kakudate, Satoshi; Nakahira, Masataka

    1994-10-01

    An articulated-arm type manipulator can be operated effectively in a restricted space due to its flexibility and it can be attractive for a wide range of in-vessel maintenance such as viewing, inspection and limiter handling in fusion experimental reactors. In case of the in-vessel maintenance using a flexible manipulator, it is quite essential to develop an autonomous control method for compensating a deflection of manipulator so as to minimize the maintenance time with high precision. For this purpose, a new position control method using a combination of neural network predictor with a rigid inverse kinematics is being developed. The key features of this method are to simplify a kinematics modeling of flexible manipulator, to enable quick position compensation in stead of ordinary large matrix compensation, and to be applicable to a wide variety of manipulator characteristics. A sub-scaled model of flexible manipulator with 4 joints has been fabricated for a benchmark experiments of the autonomous position control. Comparing analytical simulation with experiments using the flexible manipulator, it has been demonstrated that the new position control method gives significant improvement in control performance with high precision in order of a figure. In addition, further optimization can be possible by adding other non-linear predictors such as radial basis function and fuzzy modeling. This paper describes the details of a sub-scaled flexible manipulator and a neural network position control system as well as results of analytical simulation and benchmark experiments. (author)

  11. A test of positive affect induction for countering self-control depletion in cigarette smokers.

    Science.gov (United States)

    Shmueli, Dikla; Prochaska, Judith J

    2012-03-01

    The self-control strength model posits that exerting self-control on one task, such as resisting temptations, will deplete self-control and impair subsequent self-regulatory performance, such as controlling smoking. The current study examined interventions designed to replenish depleted self-control strength to prevent tobacco use by inducing positive affect. In a 2 × 2 design, 200 participants were randomized to either (1) resist eating from a plate of desserts (high temptation) or from a plate of raw vegetables (low temptation) and then (2) undergo a positive or neutral affect induction. Two inductions were compared (video vs. writing technique). Participants were then given a 10-min recess. Whether or not participants smoked during the recess, assessed by self-report and biochemical verification, served as the primary dependent variable. The interaction between depletion and exposure group was significant, Wald's χ² = 9.66, df = 3, p desserts, 65.5% to 85% smoked if they were in the neutral video or writing conditions versus 10.5% in the positive affect video group. Positive affect elicited with a video was able to counteract the detrimental effects of self-control depletion on smoking behavior, while writing exercises were associated with smoking. Implications for tobacco cessation intervention are discussed. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  12. Position Control of the Single Spherical Wheel Mobile Robot by Using the Fuzzy Sliding Mode Controller

    OpenAIRE

    Hamed Navabi; Soroush Sadeghnejad; Sepehr Ramezani; Jacky Baltes

    2017-01-01

    A spherical wheel robot or Ballbot—a robot that balances on an actuated spherical ball—is a new and recent type of robot in the popular area of mobile robotics. This paper focuses on the modeling and control of such a robot. We apply the Lagrangian method to derive the governing dynamic equations of the system. We also describe a novel Fuzzy Sliding Mode Controller (FSMC) implemented to control a spherical wheel mobile robot. The nonlinear nature of the equations makes the controller nontrivi...

  13. Position feedback control of a nonmagnetic body levitated in magnetic fluid

    International Nuclear Information System (INIS)

    Lee, J H; Nam, Y J; Park, M K; Yamane, R

    2009-01-01

    This paper is concerned with the position feedback control of a magnetic fluid actuator which is characterized by the passive levitation of a nonmagnetic body immersed in a magnetic fluid under magnetic fields. First of all, the magnetic fluid actuator is designed based on the ferrohydrostatic relation. After manufacturing the actuator, its static and dynamic characteristics are investigated experimentally. With the aid of the dynamic governing relation obtained experimentally and the proportional-derivative controller, the position tracking control of the actuator is carried out both theoretically and experimentally. As a result, the applicability of the proposed magnetic fluid actuator to various engineering devices is verified.

  14. Musical Applications and Design Techniques for the Gametrak Tethered Spatial Position Controller

    DEFF Research Database (Denmark)

    Freed, Adrian; Overholt, Daniel; Hansen, Anne-Marie

    2009-01-01

    The Gametrak spatial position controller has been saved from the fate of so many discontinued gaming controllers to become an attractive and increasingly popular platform for experimental musical controllers, math and science manipulatives, large scale interactive installations and as a playful...... tangible gaming interface that promotes inter-generational creative play and discovery . After introducing the peculiarities of the GameTrak and comparing it to related spatial position sensing systems we survey musical applications of the device. The short paper format cannot do justice to the depth...

  15. Robust independent modal space control of a coupled nano-positioning piezo-stage

    Science.gov (United States)

    Zhu, Wei; Yang, Fufeng; Rui, Xiaoting

    2018-06-01

    In order to accurately control a coupled 3-DOF nano-positioning piezo-stage, this paper designs a hybrid controller. In this controller, a hysteresis observer based on a Bouc-Wen model is established to compensate the hysteresis nonlinearity of the piezoelectric actuator first. Compared to hysteresis compensations using Preisach model and Prandt-Ishlinskii model, the compensation method using the hysteresis observer is computationally lighter. Then, based on the proposed dynamics model, by constructing the modal filter, a robust H∞ independent modal space controller is designed and utilized to decouple the piezo-stage and deal with the unmodeled dynamics, disturbance, and hysteresis compensation error. The effectiveness of the proposed controller is demonstrated experimentally. The experimental results show that the proposed controller can significantly achieve the high-precision positioning.

  16. Combined Docking with Classical Force Field and Quantum Chemical Semiempirical Method PM7

    Directory of Open Access Journals (Sweden)

    A. V. Sulimov

    2017-01-01

    Full Text Available Results of the combined use of the classical force field and the recent quantum chemical PM7 method for docking are presented. Initially the gridless docking of a flexible low molecular weight ligand into the rigid target protein is performed with the energy function calculated in the MMFF94 force field with implicit water solvent in the PCM model. Among several hundred thousand local minima, which are found in the docking procedure, about eight thousand lowest energy minima are chosen and then energies of these minima are recalculated with the recent quantum chemical semiempirical PM7 method. This procedure is applied to 16 test complexes with different proteins and ligands. For almost all test complexes such energy recalculation results in the global energy minimum configuration corresponding to the ligand pose near the native ligand position in the crystalized protein-ligand complex. A significant improvement of the ligand positioning accuracy comparing with MMFF94 energy calculations is demonstrated.

  17. Combined Docking with Classical Force Field and Quantum Chemical Semiempirical Method PM7.

    Science.gov (United States)

    Sulimov, A V; Kutov, D C; Katkova, E V; Sulimov, V B

    2017-01-01

    Results of the combined use of the classical force field and the recent quantum chemical PM7 method for docking are presented. Initially the gridless docking of a flexible low molecular weight ligand into the rigid target protein is performed with the energy function calculated in the MMFF94 force field with implicit water solvent in the PCM model. Among several hundred thousand local minima, which are found in the docking procedure, about eight thousand lowest energy minima are chosen and then energies of these minima are recalculated with the recent quantum chemical semiempirical PM7 method. This procedure is applied to 16 test complexes with different proteins and ligands. For almost all test complexes such energy recalculation results in the global energy minimum configuration corresponding to the ligand pose near the native ligand position in the crystalized protein-ligand complex. A significant improvement of the ligand positioning accuracy comparing with MMFF94 energy calculations is demonstrated.

  18. Solvated protein-DNA docking using HADDOCK

    Energy Technology Data Exchange (ETDEWEB)

    Dijk, Marc van; Visscher, Koen M.; Kastritis, Panagiotis L.; Bonvin, Alexandre M. J. J., E-mail: a.m.j.j.bonvin@uu.nl [Utrecht University, Bijvoet Center for Biomolecular Research, Faculty of Science-Chemistry (Netherlands)

    2013-05-15

    Interfacial water molecules play an important role in many aspects of protein-DNA specificity and recognition. Yet they have been mostly neglected in the computational modeling of these complexes. We present here a solvated docking protocol that allows explicit inclusion of water molecules in the docking of protein-DNA complexes and demonstrate its feasibility on a benchmark of 30 high-resolution protein-DNA complexes containing crystallographically-determined water molecules at their interfaces. Our protocol is capable of reproducing the solvation pattern at the interface and recovers hydrogen-bonded water-mediated contacts in many of the benchmark cases. Solvated docking leads to an overall improvement in the quality of the generated protein-DNA models for cases with limited conformational change of the partners upon complex formation. The applicability of this approach is demonstrated on real cases by docking a representative set of 6 complexes using unbound protein coordinates, model-built DNA and knowledge-based restraints. As HADDOCK supports the inclusion of a variety of NMR restraints, solvated docking is also applicable for NMR-based structure calculations of protein-DNA complexes.

  19. Solvated protein–DNA docking using HADDOCK

    International Nuclear Information System (INIS)

    Dijk, Marc van; Visscher, Koen M.; Kastritis, Panagiotis L.; Bonvin, Alexandre M. J. J.

    2013-01-01

    Interfacial water molecules play an important role in many aspects of protein–DNA specificity and recognition. Yet they have been mostly neglected in the computational modeling of these complexes. We present here a solvated docking protocol that allows explicit inclusion of water molecules in the docking of protein–DNA complexes and demonstrate its feasibility on a benchmark of 30 high-resolution protein–DNA complexes containing crystallographically-determined water molecules at their interfaces. Our protocol is capable of reproducing the solvation pattern at the interface and recovers hydrogen-bonded water-mediated contacts in many of the benchmark cases. Solvated docking leads to an overall improvement in the quality of the generated protein–DNA models for cases with limited conformational change of the partners upon complex formation. The applicability of this approach is demonstrated on real cases by docking a representative set of 6 complexes using unbound protein coordinates, model-built DNA and knowledge-based restraints. As HADDOCK supports the inclusion of a variety of NMR restraints, solvated docking is also applicable for NMR-based structure calculations of protein–DNA complexes.

  20. Studies on performances of the control system of plasma position and shape

    International Nuclear Information System (INIS)

    Aikawa, Hiroshi; Tsuzuki, Naohisa; Kimura, Toyoaki; Ogata, Atsushi; Ninomiya, Hiromasa

    1978-09-01

    Performance in the control system of plasma position and shape is determined by estimating the disturbing field, system functions and load variation of the controlled object. Various stray fields are considered as disturbing field. Plasma internal inductance and poloidal beta are taken into consideration as load variation of the controlled object. The required performance is obtained through considerations of plasma equilibrium, stability, impurity concentration and sensors accuracy. The results are described as requests to the poloidal power supply system. (author)

  1. Robust quasi NID current and flux control of an induction motor for position control

    NARCIS (Netherlands)

    van Duijnhoven, M.; Blachuta, M.J.

    1999-01-01

    In the paper, a new control design method called Dynamic Contraction method is applied to the flux and quadrature current robust control of an induction motor operated using the field orientation principle. The resulting input-output decoupled and linearized drive is then used for time-optimal

  2. Design of L1 -Adaptive Controller for Single Axis Positioning Table

    Directory of Open Access Journals (Sweden)

    Amjad Jalil Humaidi

    2017-11-01

    Full Text Available L1 adaptive controller has proven to provide fast adaptation with guaranteed transients in a large variety of systems. It is commonly used for controlling systems with uncertain time-varying unknown parameters. The effectiveness of L1 adaptive controller for position control of single axis has been examined and compared with Model Reference Adaptive Controller (MRAC. The Linear servo motor is one of the main constituting elements of the x-y table which is mostly used in automation application. It is characterized by time-varying friction and disturbance

  3. Positioning and tracking control system analysis for mobile free space optical network

    Science.gov (United States)

    Li, Yushan; Refai, Hazem; Sluss, , James J., Jr.; Verma, Pramode; LoPresti, Peter

    2005-08-01

    Free Space Optical (FSO) communication has evolved to be applied to the mobile network, because it can provide up to 2.5Gbps or higher data rate wireless communication. One of the key challenges with FSO systems is to maintain the Line of Sight (LOS) between transmitter and receiver. In this paper, the feasibility and performance of applying the FSO technology to the mobile network is explored, and the design plan of the attitude positioning and tracking control system of the FSO transceiver is investigated. First, the system architecture is introduced, the requirements for the control system are analyzed, the involved reference frames and frame transformation are presented. Second, the control system bandwidth is used to evaluate the system performance in controlling a positioning system consisting of a gimbal and a steering mirror, some definitions to describe the positioning accuracy and tracking capacity are given. The attitude control of a FSO transceiver is split into 2 similar channels: pitch and yaw. Using an equivalent linear control system model, the simulations are carried out, with and without the presence of uncertainties that includes GPS data errors and sensor measurement errors. Finally, based on the simulation results in the pitch channel, the quantitative evaluation on the performance of the control system is given, including positioning accuracy, tracking capability and uncertainty tolerance.

  4. Position calibration of a 3-DOF hand-controller with hybrid structure

    Science.gov (United States)

    Zhu, Chengcheng; Song, Aiguo

    2017-09-01

    A hand-controller is a human-robot interactive device, which measures the 3-DOF (Degree of Freedom) position of the human hand and sends it as a command to control robot movement. The device also receives 3-DOF force feedback from the robot and applies it to the human hand. Thus, the precision of 3-DOF position measurements is a key performance factor for hand-controllers. However, when using a hybrid type 3-DOF hand controller, various errors occur and are considered originating from machining and assembly variations within the device. This paper presents a calibration method to improve the position tracking accuracy of hybrid type hand-controllers by determining the actual size of the hand-controller parts. By re-measuring and re-calibrating this kind of hand-controller, the actual size of the key parts that cause errors is determined. Modifying the formula parameters with the actual sizes, which are obtained in the calibrating process, improves the end position tracking accuracy of the device.

  5. Study of Globus-M Tokamak Poloidal System and Plasma Position Control

    Science.gov (United States)

    Dokuka, V. N.; Korenev, P. S.; Mitrishkin, Yu. V.; Pavlova, E. A.; Patrov, M. I.; Khayrutdinov, R. R.

    2017-12-01

    In order to provide efficient performance of tokamaks with vertically elongated plasma position, control systems for limited and diverted plasma configuration are required. The accuracy, stability, speed of response, and reliability of plasma position control as well as plasma shape and current control depend on the performance of the control system. Therefore, the problem of the development of such systems is an important and actual task in modern tokamaks. In this study, the measured signals from the magnetic loops and Rogowski coils are used to reconstruct the plasma equilibrium, for which linear models in small deviations are constructed. We apply methods of the H∞-optimization theory to the synthesize control system for vertical and horizontal position of plasma capable to working with structural uncertainty of the models of the plant. These systems are applied to the plasma-physical DINA code which is configured for the tokamak Globus-M plasma. The testing of the developed systems applied to the DINA code with Heaviside step functions have revealed the complex dynamics of plasma magnetic configurations. Being close to the bifurcation point in the parameter space of unstable plasma has made it possible to detect an abrupt change in the X-point position from the top to the bottom and vice versa. Development of the methods for reconstruction of plasma magnetic configurations and experience in designing plasma control systems with feedback for tokamaks provided an opportunity to synthesize new digital controllers for plasma vertical and horizontal position stabilization. It also allowed us to test the synthesized digital controllers in the closed loop of the control system with the DINA code as a nonlinear model of plasma.

  6. Terminal homing position estimation forAutonomous underwater vehicle docking

    Science.gov (United States)

    2017-06-01

    mathematical tool to execute the computations in the MHE application . Zanon et al. also used the real-time iteration scheme with shifting since the...density estimation of simulation output, as well as electricity demand forecasts with respect to weather conditions. In all of these applications , epi...sub-optimal filter. The UKF, on the other hand, is considered an optimal filter. The UKF employs the UT, which is used in calculating the statistics

  7. Incentive-Rewarding Mechanism for User-position Control in Mobile Services

    Science.gov (United States)

    Yoshino, Makoto; Sato, Kenichiro; Shinkuma, Ryoichi; Takahashi, Tatsuro

    When the number of users in a service area increases in mobile multimedia services, no individual user can obtain satisfactory radio resources such as bandwidth and signal power because the resources are limited and shared. A solution for such a problem is user-position control. In the user-position control, the operator informs users of better communication areas (or spots) and navigates them to these positions. However, because of subjective costs caused by subjects moving from their original to a new position, they do not always attempt to move. To motivate users to contribute their resources in network services that require resource contributions for users, incentive-rewarding mechanisms have been proposed. However, there are no mechanisms that distribute rewards appropriately according to various subjective factors involving users. Furthermore, since the conventional mechanisms limit how rewards are paid, they are applicable only for the network service they targeted. In this paper, we propose a novel incentive-rewarding mechanism to solve these problems, using an external evaluator and interactive learning agents. We also investigated ways of appropriately controlling rewards based on user contributions and system service quality. We applied the proposed mechanism and reward control to the user-position control, and demonstrated its validity.

  8. The control system position to the electric probe in the Tokamak Novillo

    International Nuclear Information System (INIS)

    Sanchez Garcia, A.M.

    1993-01-01

    The electric probe are used to determine the parameters of electronic temperatures, the electron density and the plasma potential in Tokamak machines. On this machines the electric probes are used only in the plasma edge due to the intensive flow of high energy particles. This is the region in which the plasma density and temperature are relatively low. It is showed, in this work, the design and construction of an electro mechanic system which is used to control the position of the probe into the discharge chamber. This system is called T he control system position to the electric probe in the tokamak Novillo . This controller is a minimum system that is in charge , by a programming, to rule a step motor by a logic sequence commutation. This is done with the purpose of slide the probe in a radial way with a milli metric precision into the discharge chamber. To this purpose it is used a step motor, due it is principal characteristic is the control of the end element position without a feedback needing of the wrong signal. The system function consist on reading, through a board, the corresponding data to the position where it is wanted to place the probe, it also displays by a numeric indicator the position in which the probe is located (in an interval from 0 to 100 mm), and provide the logic sequence commutation for the step motor. The minimum system is constituted by the micro controller 8748-8 that gives with all precision the control of the electric probe position in the Tokamak Novillo, by programming, associated circuits, amplification unit bi phase unipolar and switching power (they supply the power to the control circuit and to the step motor too), avoiding the destruction of the electric probe. (Author). 17 refs, 29 figs

  9. Electro-optical rendezvous and docking sensors

    Science.gov (United States)

    Tubbs, David J.; Kesler, Lynn O.; Sirko, Robert J.

    1991-01-01

    Electro-optical sensors provide unique and critical functionality for space missions requiring rendezvous, docking, and berthing. McDonnell Douglas is developing a complete rendezvous and docking system for both manned and unmanned missions. This paper examines our sensor development and the systems and missions which benefit from rendezvous and docking sensors. Simulation results quantifying system performance improvements in key areas are given, with associated sensor performance requirements. A brief review of NASA-funded development activities and the current performance of electro-optical sensors for space applications is given. We will also describe current activities at McDonnell Douglas for a fully functional demonstration to address specific NASA mission needs.

  10. BP neural network tuned PID controller for position tracking of a pneumatic artificial muscle.

    Science.gov (United States)

    Fan, Jizhuang; Zhong, Jun; Zhao, Jie; Zhu, Yanhe

    2015-01-01

    Although Pneumatic Artificial Muscle (PAM) has a promising future in rehabilitation robots, it's difficult to realize accurate position control due to its highly nonlinear properties. This paper deals with position control of PAM. To describe the hysteresis inside PAM, a polynomial based phenomenological function is developed. Based on the phenomenological model for PAM and analysis of pressure dynamics within PAM, an adaptive cascade controller is proposed. Both outer loop and inner loop employ BP Neural Network tuned PID algorithm. The outer loop is to handle high nonlinearities and unmodeled dynamics of PAM, while the inner loop is responsible for nonlinearities caused by pressure dynamics. Experimental results show high tracking accuracy as compared with a convention PID controller. The proposed controller is effective in improving performance of PAM and will be implemented in a rehabilitation robot.

  11. Diagnosis and Fault-Tolerant Control for Thruster-Assisted Position Mooring System

    DEFF Research Database (Denmark)

    Nguyen, Trong Dong; Blanke, Mogens; Sørensen, Asgeir

    2007-01-01

    Development of fault-tolerant control systems is crucial to maintain safe operation of o®shore installations. The objective of this paper is to develop a fault- tolerant control for thruster-assisted position mooring (PM) system with faults occurring in the mooring lines. Faults in line......'s pretension or line breaks will degrade the performance of the positioning of the vessel. Faults will be detected and isolated through a fault diagnosis procedure. When faults are detected, they can be accommodated through the control action in which only parameter of the controlled plant has to be updated...... to cope with the faulty condition. Simulations will be carried out to verify the advantages of the fault-tolerant control strategy for the PM system....

  12. A remote handling rate-position controller for telemanipulating in a large workspace

    International Nuclear Information System (INIS)

    Barrio, Jorge; Ferre, Manuel; Suárez-Ruiz, Francisco; Aracil, Rafael

    2014-01-01

    This paper presents a new haptic rate-position controller, which allows manipulating a slave robot in a large workspace using a small haptic device. This control algorithm is very effective when the master device is much smaller than the slave device. Haptic information is displayed to the user so as to be informed when a change in the operation mode occurs. This controller allows performing tasks in a large remote workspace by using a haptic device with a reduced workspace such as Phantom. Experimental results have been carried out using a slave robot from Kraft Telerobotics and a commercial haptic interface as a master device. A curvature path following task has been simulated using the proposed controller which was compared with the force-position control algorithm. Results obtained show that higher accuracy is obtained when the proposed method is used, spending a similar amount of time to perform the task

  13. A remote handling rate-position controller for telemanipulating in a large workspace

    Energy Technology Data Exchange (ETDEWEB)

    Barrio, Jorge, E-mail: jordi.barrio@upm.es; Ferre, Manuel, E-mail: m.ferre@upm.es; Suárez-Ruiz, Francisco, E-mail: fa.suarez@upm.es; Aracil, Rafael, E-mail: rafael.aracil@upm.es

    2014-01-15

    This paper presents a new haptic rate-position controller, which allows manipulating a slave robot in a large workspace using a small haptic device. This control algorithm is very effective when the master device is much smaller than the slave device. Haptic information is displayed to the user so as to be informed when a change in the operation mode occurs. This controller allows performing tasks in a large remote workspace by using a haptic device with a reduced workspace such as Phantom. Experimental results have been carried out using a slave robot from Kraft Telerobotics and a commercial haptic interface as a master device. A curvature path following task has been simulated using the proposed controller which was compared with the force-position control algorithm. Results obtained show that higher accuracy is obtained when the proposed method is used, spending a similar amount of time to perform the task.

  14. A switched energy saving position controller for variable-pressure electro-hydraulic servo systems.

    Science.gov (United States)

    Tivay, Ali; Zareinejad, Mohammad; Rezaei, S Mehdi; Baghestan, Keivan

    2014-07-01

    The electro-hydraulic servo system (EHSS) demonstrates a relatively low level of efficiency compared to other available actuation methods. The objective of this paper is to increase this efficiency by introducing a variable supply pressure into the system and controlling this pressure during the task of position tracking. For this purpose, an EHSS structure with controllable supply pressure is proposed and its dynamic model is derived from the basic laws of physics. A switching control structure is then proposed to control both the supply pressure and the cylinder position at the same time, in a way that reduces the overall energy consumption of the system. The stability of the proposed switching control system is guaranteed by proof, and its performance is verified by experimental testing. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Position and force control of a vehicle with two or more steerable drive wheels

    Energy Technology Data Exchange (ETDEWEB)

    Reister, D.B.; Unseren, M.A.

    1992-10-01

    When a vehicle with two or more steerable drive wheels is traveling in a circle, the motion of the wheels is constrained. The wheel translational velocity divided by the radius to the center of rotation must be the same for all wheels. When the drive wheels are controlled independently using position control, the motion of the wheels may violate the constraints and the wheels may slip. Consequently, substantial errors can occur in the orientation of the vehicle. A vehicle with N drive wheels has (N - 1) constraints and one degree of freedom. We have developed a new approach to the control of a vehicle with N steerable drive wheels. The novel aspect of our approach is the use of force control. To control the vehicle, we have one degree of freedom for the position on the circle and (N - 1) forces that can be used to reduce errors. Recently, Kankaanranta and Koivo developed a control architecture that allows the force and position degrees of freedom to be decoupled. In the work of Kankaanranta and Koivo the force is an exogenous input. We have made the force endogenous by defining the force in terms of the errors in satisfying the rigid body kinematic constraints. We have applied the control architecture to the HERMIES-III robot and have measured a dramatic reduction in error (more than a factor of 20) compared to motions without force control.

  16. Protein docking prediction using predicted protein-protein interface

    Directory of Open Access Journals (Sweden)

    Li Bin

    2012-01-01

    Full Text Available Abstract Background Many important cellular processes are carried out by protein complexes. To provide physical pictures of interacting proteins, many computational protein-protein prediction methods have been developed in the past. However, it is still difficult to identify the correct docking complex structure within top ranks among alternative conformations. Results We present a novel protein docking algorithm that utilizes imperfect protein-protein binding interface prediction for guiding protein docking. Since the accuracy of protein binding site prediction varies depending on cases, the challenge is to develop a method which does not deteriorate but improves docking results by using a binding site prediction which may not be 100% accurate. The algorithm, named PI-LZerD (using Predicted Interface with Local 3D Zernike descriptor-based Docking algorithm, is based on a pair wise protein docking prediction algorithm, LZerD, which we have developed earlier. PI-LZerD starts from performing docking prediction using the provided protein-protein binding interface prediction as constraints, which is followed by the second round of docking with updated docking interface information to further improve docking conformation. Benchmark results on bound and unbound cases show that PI-LZerD consistently improves the docking prediction accuracy as compared with docking without using binding site prediction or using the binding site prediction as post-filtering. Conclusion We have developed PI-LZerD, a pairwise docking algorithm, which uses imperfect protein-protein binding interface prediction to improve docking accuracy. PI-LZerD consistently showed better prediction accuracy over alternative methods in the series of benchmark experiments including docking using actual docking interface site predictions as well as unbound docking cases.

  17. Protein docking prediction using predicted protein-protein interface.

    Science.gov (United States)

    Li, Bin; Kihara, Daisuke

    2012-01-10

    Many important cellular processes are carried out by protein complexes. To provide physical pictures of interacting proteins, many computational protein-protein prediction methods have been developed in the past. However, it is still difficult to identify the correct docking complex structure within top ranks among alternative conformations. We present a novel protein docking algorithm that utilizes imperfect protein-protein binding interface prediction for guiding protein docking. Since the accuracy of protein binding site prediction varies depending on cases, the challenge is to develop a method which does not deteriorate but improves docking results by using a binding site prediction which may not be 100% accurate. The algorithm, named PI-LZerD (using Predicted Interface with Local 3D Zernike descriptor-based Docking algorithm), is based on a pair wise protein docking prediction algorithm, LZerD, which we have developed earlier. PI-LZerD starts from performing docking prediction using the provided protein-protein binding interface prediction as constraints, which is followed by the second round of docking with updated docking interface information to further improve docking conformation. Benchmark results on bound and unbound cases show that PI-LZerD consistently improves the docking prediction accuracy as compared with docking without using binding site prediction or using the binding site prediction as post-filtering. We have developed PI-LZerD, a pairwise docking algorithm, which uses imperfect protein-protein binding interface prediction to improve docking accuracy. PI-LZerD consistently showed better prediction accuracy over alternative methods in the series of benchmark experiments including docking using actual docking interface site predictions as well as unbound docking cases.

  18. Design of a Single-Cell Positioning Controller Using Electroosmotic Flow and Image Processing

    Directory of Open Access Journals (Sweden)

    Jhong-Yin Chen

    2013-05-01

    Full Text Available The objective of the current research was not only to provide a fast and automatic positioning platform for single cells, but also improved biomolecular manipulation techniques. In this study, an automatic platform for cell positioning using electroosmotic flow and image processing technology was designed. The platform was developed using a PCI image acquisition interface card for capturing images from a microscope and then transferring them to a computer using human-machine interface software. This software was designed by the Laboratory Virtual Instrument Engineering Workbench, a graphical language for finding cell positions and viewing the driving trace, and the fuzzy logic method for controlling the voltage or time of an electric field. After experiments on real human leukemic cells (U-937, the success of the cell positioning rate achieved by controlling the voltage factor reaches 100% within 5 s. A greater precision is obtained when controlling the time factor, whereby the success rate reaches 100% within 28 s. Advantages in both high speed and high precision are attained if these two voltage and time control methods are combined. The control speed with the combined method is about 5.18 times greater than that achieved by the time method, and the control precision with the combined method is more than five times greater than that achieved by the voltage method.

  19. Hysteresis Analysis and Positioning Control for a Magnetic Shape Memory Actuator

    Science.gov (United States)

    Lin, Jhih-Hong; Chiang, Mao-Hsiung

    2015-01-01

    Magnetic shape memory alloys (MSM alloys), a new kind of smart materials, have become a potential candidate in many engineering fields. MSMs have the advantage of bearing a huge strain, much larger than other materials. In addition, they also have fast response. These characteristics make MSM a good choice in micro engineering. However, MSMs display the obvious hysteresis phenomenon of nonlinear behavior. Thus the difficulty in using the MSM element as a positioning actuator is increased due to the hysteresis. In this paper, the hysteresis phenomenon of the MSM actuator is analyzed, and the closed-loop positioning control is also implemented experimentally. For that, a modified fuzzy sliding mode control (MFSMC) is proposed. The MFSMC and the PID control are used to design the controllers for realizing the positioning control. The experimental results are compared under different experimental conditions, such as different frequency, amplitude, and loading. The experimental results show that the precise positioning control of MFSMC can be achieved satisfactorily. PMID:25853405

  20. AnchorDock: Blind and Flexible Anchor-Driven Peptide Docking.

    Science.gov (United States)

    Ben-Shimon, Avraham; Niv, Masha Y

    2015-05-05

    The huge conformational space stemming from the inherent flexibility of peptides is among the main obstacles to successful and efficient computational modeling of protein-peptide interactions. Current peptide docking methods typically overcome this challenge using prior knowledge from the structure of the complex. Here we introduce AnchorDock, a peptide docking approach, which automatically targets the docking search to the most relevant parts of the conformational space. This is done by precomputing the free peptide's structure and by computationally identifying anchoring spots on the protein surface. Next, a free peptide conformation undergoes anchor-driven simulated annealing molecular dynamics simulations around the predicted anchoring spots. In the challenging task of a completely blind docking test, AnchorDock produced exceptionally good results (backbone root-mean-square deviation ≤ 2.2Å, rank ≤15) for 10 of 13 unbound cases tested. The impressive performance of AnchorDock supports a molecular recognition pathway that is driven via pre-existing local structural elements. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. SAMPL4 & DOCK3.7: lessons for automated docking procedures

    Science.gov (United States)

    Coleman, Ryan G.; Sterling, Teague; Weiss, Dahlia R.

    2014-03-01

    The SAMPL4 challenges were used to test current automated methods for solvation energy, virtual screening, pose and affinity prediction of the molecular docking pipeline DOCK 3.7. Additionally, first-order models of binding affinity were proposed as milestones for any method predicting binding affinity. Several important discoveries about the molecular docking software were made during the challenge: (1) Solvation energies of ligands were five-fold worse than any other method used in SAMPL4, including methods that were similarly fast, (2) HIV Integrase is a challenging target, but automated docking on the correct allosteric site performed well in terms of virtual screening and pose prediction (compared to other methods) but affinity prediction, as expected, was very poor, (3) Molecular docking grid sizes can be very important, serious errors were discovered with default settings that have been adjusted for all future work. Overall, lessons from SAMPL4 suggest many changes to molecular docking tools, not just DOCK 3.7, that could improve the state of the art. Future difficulties and projects will be discussed.

  2. Hydrostatic control system for the height position of the JINR synchrotron

    International Nuclear Information System (INIS)

    Vasyutinskij, I.Yu.; Zinov'ev, L.P.; Karpov, I.I.

    1978-01-01

    Hydrostatic system with remote read-out is created for a more operative control of height position of synchrocyclotrone electromagnet. 3 hydrostatic heads with electrocontact registration of liquid level position were mounted on every electromagnet quadrant. The heads are placed under the magnet in centers of survey channel of the foundation and are switched on in series. Teh schemes of the main system units are given. The order of assembling and adjustment of hydrostatic system elements of the accelerator is described

  3. Proximity Operations and Docking Sensor Development

    Science.gov (United States)

    Howard, Richard T.; Bryan, Thomas C.; Brewster, Linda L.; Lee, James E.

    2009-01-01

    The Next Generation Advanced Video Guidance Sensor (NGAVGS) has been under development for the last three years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in spot mode out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. 12 Parts obsolescence issues prevent the construction of more AVGS units, and the next generation sensor was updated to allow it to support the CEV and COTS programs. The flight proven AR&D sensor has been redesigned to update parts and add additional capabilities for CEV and COTS with the development of the Next Generation AVGS at the Marshall Space Flight Center. The obsolete imager and processor are being replaced with new radiation tolerant parts. In addition, new capabilities include greater sensor range, auto ranging capability, and real-time video output. This paper presents some sensor hardware trades, use of highly integrated laser components, and addresses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements

  4. Application of robot kinematics methods to the simulation and control of neutron beam line positioning systems

    Energy Technology Data Exchange (ETDEWEB)

    James, Jonathan A. [Open University, Materials Engineering, Walton Hall, Milton Keynes, Buckinghamshire MK7 6AA (United Kingdom)]. E-mail: j.a.j.james@open.ac.uk; Edwards, Lyndon [Open University, Materials Engineering, Walton Hall, Milton Keynes, Buckinghamshire MK7 6AA (United Kingdom)

    2007-02-11

    Neutron stress measurements require specimens of complex geometry to be speedily and accurately positioned and oriented with respect to the neutron beam. Recognition that a majority of the specimen positioning systems in use at strain scanning facilities are effectively serial robot manipulators, suggests that the methods of serial robot kinematic modelling may be applied to advantage. The adoption of robotics methods provides a simple and reliable framework for controlling positioning systems of arbitrary geometry and complexity. In addition the numerical solution of the inverse kinematic problem is facilitated, allowing specimens to be automatically positioned and orientated so that pre-determined strain components are measured. It is also shown that, given sufficient degrees of freedom, a secondary characteristic of the measurement position such as the measurement count time may be simultaneously optimised.

  5. Method of improving heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control

    Science.gov (United States)

    Zhao, Ling; Xia, Huifen

    2018-01-01

    The project of polymer flooding has achieved great success in Daqing oilfield, and the main oil reservoir recovery can be improved by more than 15%. But, for some strong oil reservoir heterogeneity carrying out polymer flooding, polymer solution will be inefficient and invalid loop problem in the high permeability layer, then cause the larger polymer volume, and a significant reduction in the polymer flooding efficiency. Aiming at this problem, it is studied the method that improves heterogeneous oil reservoir polymer flooding effect by positively-charged gel profile control. The research results show that the polymer physical and chemical reaction of positively-charged gel with the residual polymer in high permeability layer can generate three-dimensional network of polymer, plugging high permeable layer, and increase injection pressure gradient, then improve the effect of polymer flooding development. Under the condition of the same dosage, positively-charged gel profile control can improve the polymer flooding recovery factor by 2.3∼3.8 percentage points. Under the condition of the same polymer flooding recovery factor increase value, after positively-charged gel profile control, it can reduce the polymer volume by 50 %. Applying mechanism of positively-charged gel profile control technology is feasible, cost savings, simple construction, and no environmental pollution, therefore has good application prospect.

  6. Determination of curve 1/M profile as a function of control rod bank position

    International Nuclear Information System (INIS)

    Pereira, Valmir; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

    2002-01-01

    Determination of the subcritical multiplication curve profile (1/M) as a function of control rod bank position is of paramount importance to the development of a system which allows to foresee and also anticipate determination of criticality of a PWR reactor core. This work aims at determining this profile. For that, the 3D- two group-diffusion equations for a subcritical PWR reactor core with external neutron source is solved for different control rod bank positions. Results obtained are compared with the results from the corresponding eigenvalue problem, in order to verify how the external neutron source interferes with the reactor criticality search. (author)

  7. A Toroidally Symmetric Plasma Simulation code for design of position and shape control on tokamak plasmas

    International Nuclear Information System (INIS)

    Takase, Haruhiko; Senda, Ikuo

    1999-01-01

    A Toroidally Symmetric Plasma Simulation (TSPS) code has been developed for investigating the position and shape control on tokamak plasmas. The analyses of three-dimensional eddy currents on the conducting components around the plasma and the two-dimensional magneto-hydrodynamic (MHD) equilibrium are taken into account in this code. The code can analyze the plasma position and shape control during the minor disruption in which the deformation of plasma is not negligible. Using the ITER (International Thermonuclear Experimental Reactor) parameters, some examples of calculations are shown in this paper. (author)

  8. SwarmDock and the Use of Normal Modes in Protein-Protein Docking

    Directory of Open Access Journals (Sweden)

    Paul A. Bates

    2010-09-01

    Full Text Available Here is presented an investigation of the use of normal modes in protein-protein docking, both in theory and in practice. Upper limits of the ability of normal modes to capture the unbound to bound conformational change are calculated on a large test set, with particular focus on the binding interface, the subset of residues from which the binding energy is calculated. Further, the SwarmDock algorithm is presented, to demonstrate that the modelling of conformational change as a linear combination of normal modes is an effective method of modelling flexibility in protein-protein docking.

  9. Theoretical and experimental investigation of position-controlled semi-active friction damper for seismic structures

    Science.gov (United States)

    Lu, Lyan-Ywan; Lin, Tzu-Kang; Jheng, Rong-Jie; Wu, Hsin-Hsien

    2018-01-01

    A semi-active friction damper (SAFD) can be employed for the seismic protection of structural systems. The effectiveness of an SAFD in absorbing seismic energy is usually superior to that of its passive counterpart, since its slip force can be altered in real time according to structural response and excitation. Most existing SAFDs are controlled by adjusting the clamping force applied on the friction interface. Thus, the implementation of SAFDs in practice requires precision control of the clamping force, which is usually substantially larger than the slip force. This may increase the implementation complexity and cost of SAFDs. To avoid this problem, this study proposes a novel position-controlled SAFD, named the leverage-type controllable friction damper (LCFD). The LCFD system combines a traditional passive friction damper and a leverage mechanism with a movable central pivot. By simply controlling the pivot position, the damping force generated by the LCFD system can be adjusted in real time. In order to verify the feasibility of the proposed SAFD, a prototype LCFD was tested by using a shaking table. The test results demonstrate that the equivalent friction force and hysteresis loop of the LCFD can be regulated by controlling the pivot position. By considering 16 ground motions with two different intensities, the adaptive feature of the LCFD for seismic structural control is further demonstrated numerically.

  10. Position controller for the arm of a neutron diffractometer using fuzzy logic

    International Nuclear Information System (INIS)

    Ayala P, G.F.

    1994-01-01

    The neutron diffractometer is an important instrument coupled to one of the radial outlets of the TRIGA-3-Salazar Reactor and is used mainly to analyze textures and crystal lattices. One of its main components is the velocity analysis goniometer which controls in a tangential way the movements of the sensor requiring for this a resolution of a hundredth of degree, but at the same time wide displacements are required. It is necessary to design and construct a system on the basis of a micro controller which control the long movements in a rapid way and with the needed accuracy. In this work, a proposition is presented: to replace the A.C. motor with a D.C. motor with a wide range of velocity and supplied with a card (DAC) to control the velocity by means of digital data. Moreover, a programmed micro controller with an algorithm based on fuzzy logic receiving data in BCD will be use. The use of micro controller will allow to set free the personal computer of the position of the goniometer; nevertheless, the system will report to the P C and its control program about the present position of the goniometer and the time when the desired position is reached. It is also consider that the user will be away from the system (a minimum of 15 meters) in order to avoid the zone with a high intensity of background radiation. (Author)

  11. A Comparison between Two Force-Position Controllers with Gravity Compensation Simulated on a Humanoid Arm

    Directory of Open Access Journals (Sweden)

    Giovanni Gerardo Muscolo

    2013-01-01

    Full Text Available The authors propose a comparison between two force-position controllers with gravity compensation simulated on the DEXTER bioinspired robotic arm. The two controllers are both constituted by an internal proportional-derivative (PD closed-loop for the position control. The force control of the two systems is composed of an external proportional (P closed-loop for one system (P system and an external proportional-integrative (PI closed-loop for the other system (PI system. The simulation tests performed with the two systems on a planar representation of the DEXTER, an eight-DOF bioinspired arm, showed that by varying the stiffness of the environment, with a correct setting of parameters, both systems ensure the achievement of the desired force regime and with great precision the desired position. The two controllers do not have large differences in performance when interacting with a lower stiffness environment. In case of an environment with greater rigidity, the PI system is more stable. The subsequent implementation of these control systems on the DEXTER robotic bioinspired arm gives guidance on the design and control optimisation of the arms of the humanoid robot named SABIAN.

  12. Identification and control of plasma vertical position using neural network in Damavand tokamak

    International Nuclear Information System (INIS)

    Rasouli, H.; Rasouli, C.; Koohi, A.

    2013-01-01

    In this work, a nonlinear model is introduced to determine the vertical position of the plasma column in Damavand tokamak. Using this model as a simulator, a nonlinear neural network controller has been designed. In the first stage, the electronic drive and sensory circuits of Damavand tokamak are modified. These circuits can control the vertical position of the plasma column inside the vacuum vessel. Since the vertical position of plasma is an unstable parameter, a direct closed loop system identification algorithm is performed. In the second stage, a nonlinear model is identified for plasma vertical position, based on the multilayer perceptron (MLP) neural network (NN) structure. Estimation of simulator parameters has been performed by back-propagation error algorithm using Levenberg–Marquardt gradient descent optimization technique. The model is verified through simulation of the whole closed loop system using both simulator and actual plant in similar conditions. As the final stage, a MLP neural network controller is designed for simulator model. In the last step, online training is performed to tune the controller parameters. Simulation results justify using of the NN controller for the actual plant.

  13. Identification and control of plasma vertical position using neural network in Damavand tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Rasouli, H. [School of Plasma Physics and Nuclear Fusion, Institute of Nuclear Science and Technology, AEOI, P.O. Box 14155-1339, Tehran (Iran, Islamic Republic of); Advanced Process Automation and Control (APAC) Research Group, Faculty of Electrical Engineering, K.N. Toosi University of Technology, P.O. Box 16315-1355, Tehran (Iran, Islamic Republic of); Rasouli, C.; Koohi, A. [School of Plasma Physics and Nuclear Fusion, Institute of Nuclear Science and Technology, AEOI, P.O. Box 14155-1339, Tehran (Iran, Islamic Republic of)

    2013-02-15

    In this work, a nonlinear model is introduced to determine the vertical position of the plasma column in Damavand tokamak. Using this model as a simulator, a nonlinear neural network controller has been designed. In the first stage, the electronic drive and sensory circuits of Damavand tokamak are modified. These circuits can control the vertical position of the plasma column inside the vacuum vessel. Since the vertical position of plasma is an unstable parameter, a direct closed loop system identification algorithm is performed. In the second stage, a nonlinear model is identified for plasma vertical position, based on the multilayer perceptron (MLP) neural network (NN) structure. Estimation of simulator parameters has been performed by back-propagation error algorithm using Levenberg-Marquardt gradient descent optimization technique. The model is verified through simulation of the whole closed loop system using both simulator and actual plant in similar conditions. As the final stage, a MLP neural network controller is designed for simulator model. In the last step, online training is performed to tune the controller parameters. Simulation results justify using of the NN controller for the actual plant.

  14. Position Control Method For Pick And Place Robot Arm For Object Sorting System

    Directory of Open Access Journals (Sweden)

    Khin Moe Myint

    2015-08-01

    Full Text Available The more increase the number of industries in developing countries the more require labourers or workers in that. To reduce the cost of labour force and to increase the manufacturing capacity of industries the advanced robot arms are more needed. The aim of this journal is to eliminate the manual control for object sorting system.Robot arm design in this research uses two joints three links and servo motors to drive. Microcontroller is used to generate required PWM signal for servo motors. In this research the position control of robot arm was designed by using kinematic control methods. There are two types of kinematic control methods which are forward and reverse kinematic methods. In forward kinematic method the input parameters are the joint angles and link length of robot arm and then the output is the position at XYZ coordinate of tool or gripper. In inverse kinematic the input parameters are position at XYZ coordinate of gripper and the link length of robot arm and then the output parameters are the joint angles. So kinematic methods can explain the analytical description of the geometry motion of the manipulator with reference to a robot coordinate system fixed to a frame without consideration of the forces or the moments causing the movements. For sorting system Metal detector is used to detect the metal or non-metal. This position control of pick and place robot arm is fully tested and the result is obtained more precisely.

  15. A Clustered Randomized Controlled Trial of the Positive Prevention PLUS Adolescent Pregnancy Prevention Program.

    Science.gov (United States)

    LaChausse, Robert G

    2016-09-01

    To determine the impact of Positive Prevention PLUS, a school-based adolescent pregnancy prevention program on delaying sexual intercourse, birth control use, and pregnancy. I randomly assigned a diverse sample of ninth grade students in 21 suburban public high schools in California into treatment (n = 2483) and control (n = 1784) groups that participated in a clustered randomized controlled trial. Between October 2013 and May 2014, participants completed baseline and 6-month follow-up surveys regarding sexual behavior and pregnancy. Participants in the treatment group were offered Positive Prevention PLUS, an 11-lesson adolescent pregnancy prevention program. The program had statistically significant impacts on delaying sexual intercourse and increasing the use of birth control. However, I detected no program effect on pregnancy rates at 6-month follow-up. The Positive Prevention PLUS program demonstrated positive impacts on adolescent sexual behavior. This suggests that programs that focus on having students practice risk reduction skills may delay sexual activity and increase birth control use.

  16. Tail Docking of Canine Puppies: Reassessment of the Tail's Role in Communication, the Acute Pain Caused by Docking and Interpretation of Behavioural Responses.

    Science.gov (United States)

    Mellor, David J

    2018-05-31

    Laws, regulations and professional standards increasingly aim to ban or restrict non-therapeutic tail docking in canine puppies. These constraints have usually been justified by reference to loss of tail participation in communication between dogs, the acute pain presumed to be caused during docking itself, subsequent experiences of chronic pain and heightened pain sensitivity, and the occurrence of other complications. These areas are reconsidered here. First, a scientifically robust examination of the dynamic functional foundations, sensory components and key features of body language that are integral to canine communication shows that the role of the tail has been greatly underestimated. More specifically, it shows that tail behaviour is so embedded in canine communication that docking can markedly impede unambiguous interactions between different dogs and between dogs and people. These interactions include the expression of wide ranges of both negative and positive emotions, moods and intentions that are of daily significance for dog welfare. Moreover, all docked dogs may experience these impediments throughout their lives, which challenges assertions by opponents to such bans or restrictions that the tail is a dispensable appendage. Second, and in contrast, a re-examination of the sensory capacities of canine puppies reveals that they cannot consciously experience acute or chronic pain during at least the first week after birth, which is when they are usually docked. The contrary view is based on questionable between-species extrapolation of information about pain from neurologically mature newborns such as calves, lambs, piglets and human infants, which certainly can consciously experience pain in response to injury, to neurologically immature puppies which remain unconscious and therefore unable to experience pain until about two weeks after birth. Third, underpinned by the incorrect conclusion that puppies are conscious at the usual docking age, it is

  17. Tail Docking of Canine Puppies: Reassessment of the Tail’s Role in Communication, the Acute Pain Caused by Docking and Interpretation of Behavioural Responses

    Directory of Open Access Journals (Sweden)

    David J. Mellor

    2018-05-01

    Full Text Available Laws, regulations and professional standards increasingly aim to ban or restrict non-therapeutic tail docking in canine puppies. These constraints have usually been justified by reference to loss of tail participation in communication between dogs, the acute pain presumed to be caused during docking itself, subsequent experiences of chronic pain and heightened pain sensitivity, and the occurrence of other complications. These areas are reconsidered here. First, a scientifically robust examination of the dynamic functional foundations, sensory components and key features of body language that are integral to canine communication shows that the role of the tail has been greatly underestimated. More specifically, it shows that tail behaviour is so embedded in canine communication that docking can markedly impede unambiguous interactions between different dogs and between dogs and people. These interactions include the expression of wide ranges of both negative and positive emotions, moods and intentions that are of daily significance for dog welfare. Moreover, all docked dogs may experience these impediments throughout their lives, which challenges assertions by opponents to such bans or restrictions that the tail is a dispensable appendage. Second, and in contrast, a re-examination of the sensory capacities of canine puppies reveals that they cannot consciously experience acute or chronic pain during at least the first week after birth, which is when they are usually docked. The contrary view is based on questionable between-species extrapolation of information about pain from neurologically mature newborns such as calves, lambs, piglets and human infants, which certainly can consciously experience pain in response to injury, to neurologically immature puppies which remain unconscious and therefore unable to experience pain until about two weeks after birth. Third, underpinned by the incorrect conclusion that puppies are conscious at the usual

  18. Asymmetric Fuzzy Control of a Positive and Negative Pneumatic Pressure Servo System

    Science.gov (United States)

    Yang, Gang; Du, Jing-Min; Fu, Xiao-Yun; Li, Bao-Ren

    2017-11-01

    The pneumatic pressure control systems have been used in some fields. However, the researches on pneumatic pressure control mainly focus on constant pressure regulation. Poor dynamic characteristics and strong nonlinearity of such systems limit its application in the field of pressure tracking control. In order to meet the demand of generating dynamic pressure signal in the application of the hardware-in-the-loop simulation of aerospace engineering, a positive and negative pneumatic pressure servo system is provided to implement dynamic adjustment of sealed chamber pressure. A mathematical model is established with simulation and experiment being implemented afterwards to discuss the characteristics of the system, which shows serious asymmetry in the process of charging and discharging. Based on the analysis of the system dynamics, a fuzzy proportional integral derivative (PID) controller with asymmetric fuzzy compensator is proposed. Different from conventional adjusting mechanisms employing the error and change in error of the controlled variable as input parameters, the current chamber pressure and charging or discharging state are chosen as inputs of the compensator, which improves adaptability. To verify the effectiveness and performance of the proposed controller, the comparison experiments tracking sinusoidal and square wave commands are conducted. Experimental results show that the proposed controller can obtain better dynamic performance and relatively consistent control performance across the scope of work (2-140 kPa). The research proposes a fuzzy control method to overcome asymmetry and enhance adaptability for the positive and negative pneumatic pressure servo system.

  19. Research of fuel temperature control in fuel pipeline of diesel engine using positive temperature coefficient material

    Directory of Open Access Journals (Sweden)

    Xiaolu Li

    2016-01-01

    Full Text Available As fuel temperature increases, both its viscosity and surface tension decrease, and this is helpful to improve fuel atomization and then better combustion and emission performances of engine. Based on the self-regulated temperature property of positive temperature coefficient material, this article used a positive temperature coefficient material as electric heating element to heat diesel fuel in fuel pipeline of diesel engine. A kind of BaTiO3-based positive temperature coefficient material, with the Curie temperature of 230°C and rated voltage of 24 V, was developed, and its micrograph and element compositions were also analyzed. By the fuel pipeline wrapped in six positive temperature coefficient ceramics, its resistivity–temperature and heating characteristics were tested on a fuel pump bench. The experiments showed that in this installation, the surface temperature of six positive temperature coefficient ceramics rose to the equilibrium temperature only for 100 s at rated voltage. In rated power supply for six positive temperature coefficient ceramics, the temperature of injection fuel improved for 21°C–27°C within 100 s, and then could keep constant. Using positive temperature coefficient material to heat diesel in fuel pipeline of diesel engine, the injection mass per cycle had little change, approximately 0.3%/°C. This study provides a beneficial reference for improving atomization of high-viscosity liquids by employing positive temperature coefficient material without any control methods.

  20. Robust balancing and position control of a single spherical wheeled mobile platform

    OpenAIRE

    Yavuz, Fırat; Yavuz, Firat; Ünel, Mustafa; Unel, Mustafa

    2016-01-01

    Self-balancing mobile platforms with single spherical wheel, generally called ballbots, are suitable example of underactuated systems. Balancing control of a ballbot platform, which aims to maintain the upright orientation by rejecting external disturbances, is important during station keeping or trajectory tracking. In this paper, acceleration based balancing and position control of a single spherical wheeled mobile platform that has three single-row omniwheel drive m...

  1. Positive Analysis of Invasive Species Control as a Dynamic Spatial Process

    OpenAIRE

    Buyuktahtakin, Esra; Feng, Zhuo; Olsson, Aaryn; Frisvold, George B.; Szidarovszky, Ferenc

    2010-01-01

    This paper models control of invasive buffelgrass (Pennisetum ciliare), a fire-prone African bunchgrass spreading rapidly across the southern Arizona desert as a spatial dynamic process. Buffelgrass spreads over a gridded landscape. Weed carrying capacity, treatment costs, and damages vary over grid cells. Damage from buffelgrass depends on its spatial distribution in relation to valued resources. We conduct positive analysis of recommended heuristic strategies for buffelgrass control, evalua...

  2. Control of plasma poloidal shape and position in the DIII-D tokamak

    International Nuclear Information System (INIS)

    Walker, M.L.; Humphreys, D.A.; Ferron, J.R.

    1997-11-01

    Historically, tokamak control design has been a combination of theory driving an initial control design and empirical tuning of controllers to achieve satisfactory performance. This approach was in line with the focus of past experiments on simply obtaining sufficient control to study many of the basic physics issues of plasma behavior. However, in recent years existing experimental devices have required increasingly accurate control. New tokamaks such as ITER or the eventual fusion power plant must achieve and confine burning fusion plasmas, placing unprecedented demands on regulation of plasma shape and position, heat flux, and burn characteristics. Control designs for such tokamaks must also function well during initial device operation with minimal empirical optimization required. All of these design requirements imply a heavy reliance on plasma modeling and simulation. Thus, plasma control design has begun to use increasingly modern and sophisticated control design methods. This paper describes some of the history of plasma control for the DIII-D tokamak as well as the recent effort to implement modern controllers. This effort improves the control so that one may obtain better physics experiments and simultaneously develop the technology for designing controllers for next-generation tokamaks

  3. Open-loop position tracking control of a piezoceramic flexible beam using a dynamic hysteresis compensator

    International Nuclear Information System (INIS)

    Nguyen, Phuong-Bac; Choi, Seung-Bok

    2010-01-01

    This paper proposes a novel hysteresis compensator to enhance control accuracy in open-loop position tracking control of a piezoceramic flexible beam. The proposed hysteresis compensator consists of two components: a rate-independent hysteresis compensator and a nonlinear filter. The compensator is formulated based on the inverse Preisach model, while the weight coefficients of the filter are identified adaptively using a recursive least square (RLS) algorithm. In this work, two dynamic hysteresis compensators (or rate-independent hysteresis compensators) are developed by adopting two different nonlinear filters: Volterra and bilinear filters. In order to demonstrate the improved control accuracy of the proposed dynamic compensators, a flexible beam associated with the piezoceramic actuator is modeled using the finite element method (FEM) and Euler–Bernoulli beam theory. The beam model is then integrated with the proposed hysteresis model to achieve accurate position tracking control at the tip of the beam. An experimental investigation on the tip position tracking control is undertaken by realizing three different hysteresis compensators: a rate-independent hysteresis compensator, a rate-dependent hysteresis compensator with a Volterra nonlinear filter and a rate-independent hysteresis compensator with a bilinear nonlinear filter. It is shown that the proposed dynamic hysteresis compensators can provide much better tracking control accuracy than conventional rate-independent hysteresis compensators

  4. Tri-code inductance control rod position indicator with several multi-coding-bars

    International Nuclear Information System (INIS)

    Shi Jibin; Jiang Yueyuan; Wang Wenran

    2004-01-01

    A control rod position indicator named as tri-code inductance control rod position indicator with multi-coding-bars, which possesses simple structure, reliable operation and high precision, is developed. The detector of the indicator is composed of K coils, a compensatory coil and K coding bars. Each coding bar consists of several sections of strong magnetic cores, several sections of weak magnetic cores and several sections of non-magnetic portions. As the control rod is withdrawn, the coding bars move in the center of the coils respectively, while the constant alternating current passes the coils and makes them to create inductance alternating voltage signals. The outputs of the coils are picked and processed, and the tri-codes indicating rod position can be gotten. Moreover, the coding principle of the detector and its related structure are introduced. The analysis shows that the indicator owns more advantage over the coils-coding rod position indicator, so it can meet the demands of the rod position indicating in nuclear heating reactor (NHR). (authors)

  5. The HADDOCK web server for data-driven biomolecular docking

    NARCIS (Netherlands)

    de Vries, S.J.|info:eu-repo/dai/nl/304837717; van Dijk, M.|info:eu-repo/dai/nl/325811113; Bonvin, A.M.J.J.|info:eu-repo/dai/nl/113691238

    2010-01-01

    Computational docking is the prediction or modeling of the three-dimensional structure of a biomolecular complex, starting from the structures of the individual molecules in their free, unbound form. HADDOC K is a popular docking program that takes a datadriven approach to docking, with support for

  6. Testing links between childhood positive peer relations and externalizing outcomes through a randomized controlled intervention study

    NARCIS (Netherlands)

    Witvliet, M.; van Lier, P.A.C.; Cuijpers, P.; Koot, H.M.

    2009-01-01

    In this study, the authors used a randomized controlled trial to explore the link between having positive peer relations and externalizing outcomes in 758 children followed from kindergarten to the end of 2nd grade. Children were randomly assigned to the Good Behavior Game (GBG), a universal

  7. A Positive Control for Detection of Functional CD4 T Cells in PBMC: The CPI Pool.

    Science.gov (United States)

    Schiller, Annemarie; Zhang, Ting; Li, Ruliang; Duechting, Andrea; Sundararaman, Srividya; Przybyla, Anna; Kuerten, Stefanie; Lehmann, Paul V

    2017-12-07

    Testing of peripheral blood mononuclear cells (PBMC) for immune monitoring purposes requires verification of their functionality. This is of particular concern when the PBMC have been shipped or stored for prolonged periods of time. While the CEF (Cytomegalo-, Epstein-Barr and Flu-virus) peptide pool has become the gold standard for testing CD8 cell functionality, a positive control for CD4 cells is so far lacking. The latter ideally consists of proteins so as to control for the functionality of the antigen processing and presentation compartments, as well. Aiming to generate a positive control for CD4 cells, we first selected 12 protein antigens from infectious/environmental organisms that are ubiquitous: Varicella, Influenza, Parainfluenza, Mumps, Cytomegalovirus, Streptococcus , Mycoplasma , Lactobacillus , Neisseria , Candida , Rubella, and Measles. Of these antigens, three were found to elicited interferon (IFN)-γ-producing CD4 cells in the majority of human test subjects: inactivated cytomegalo-, parainfluenza-, and influenza virions (CPI). While individually none of these three antigens triggered a recall response in all donors, the pool of the three (the 'CPI pool'), did. One hundred percent of 245 human donors tested were found to be CPI positive, including Caucasians, Asians, and African-Americans. Therefore, the CPI pool appears to be suitable to serve as universal positive control for verifying the functionality of CD4 and of antigen presenting cells.

  8. Quantum dots for future nanophotonic devices : lateral ordering, position, and number control

    NARCIS (Netherlands)

    Nötzel, R.

    2010-01-01

    After the general aspects of InAs/InP (100) quantum dots (QDs) regarding the formation of QDs versus quantum dashes, wavelength tuning from telecom to mid-infrared region, and device applications, we discuss our recent progress on the lateral ordering, position, and number control of QDs.

  9. Control rod position and temperature coefficients in HTTR power-rise tests. Interim report

    International Nuclear Information System (INIS)

    Fujimoto, Nozomu; Nojiri, Naoki; Takada, Eiji; Saito, Kenji; Kobayashi, Shoichi; Sawahata, Hiroaki; Kokusen, Sigeru

    2001-03-01

    Power-rise tests of the High Temperature Engineering Test Reactor (HTTR) have been carried out aiming to achieve 100% power. So far, 50% of power operation and many tests have been carried out. In the HTTR, temperature change in core is so large to achieve the outlet coolant temperature of 950degC. To improve the calculation accuracy of the HTTR reactor physics characteristics, control rod positions at criticality and temperature coefficients were measured at each step to achieve 50% power level. The calculations were carried out using Monte Carlo code and diffusion theory with temperature distributions in the core obtained by reciprocal calculation of thermo-hydraulic code and diffusion theory. Control rod positions and temperature coefficients were calculated by diffusion theory and Monte Carlo method. The test results were compared to calculation results. The control rod positions at criticality showed good agreement with calculation results by Monte Carlo method with error of 50 mm. The control position at criticality at 100% was predicted around 2900mm. Temperature coefficients showed good agreement with calculation results by diffusion theory. The improvement of calculation will be carried out comparing the measured results up to 100% power level. (author)

  10. Radiometric control of the position of blind holes axes in graphite blocks of high temperature reactors

    International Nuclear Information System (INIS)

    Boutaine, J.L.; Bujas, R.; Lemonnier, A.; Tortel, J.

    1976-01-01

    The principles of a radiometric method intended for controlling the positions of blind hole axes are given. A comparison is made between radiometry and radiography and the performances obtained using a thulium 170 source are described. The automation capabilities are discussed [fr

  11. The Relationships between Positive Thinking Skills, Academic Locus of Control and Grit in Adolescents

    Science.gov (United States)

    Çelik, Ismail; Sariçam, Hakan

    2018-01-01

    The main purpose of this study is to examine the possible relationships between academic locus of control, positive thinking skills and grit in high school students. The participants of the research are composed of 288 adolescents continuing their high school education from 4 different schools in Agri, Turkey, which were selected with convenient…

  12. Voltage directive drive with claw pole motor and control without rotor position indicator

    Science.gov (United States)

    Stroenisch, Volker Ewald

    Design and testing of a voltage directive drive for synchronous variable speed claw pole motor and control without rotor position indicator is described. Economic analysis of the designed regulation is performed. Computations of stationary and dynamic behavior are given and experimental operational behavior is determined. The motors can be used for electric transportation vehicles, diesel motors, and electric railway engines.

  13. 78 FR 51078 - Reporting Requirements for Positive Train Control Expenses and Investments

    Science.gov (United States)

    2013-08-20

    ...] Reporting Requirements for Positive Train Control Expenses and Investments AGENCY: Surface Transportation... investments and expenses. PTC is an automated system designed to prevent train-to-train collisions and other..., PTC expenditures are incorporated into the R-1 under the category of ``capital investments and...

  14. CovalentDock Cloud: a web server for automated covalent docking.

    Science.gov (United States)

    Ouyang, Xuchang; Zhou, Shuo; Ge, Zemei; Li, Runtao; Kwoh, Chee Keong

    2013-07-01

    Covalent binding is an important mechanism for many drugs to gain its function. We developed a computational algorithm to model this chemical event and extended it to a web server, the CovalentDock Cloud, to make it accessible directly online without any local installation and configuration. It provides a simple yet user-friendly web interface to perform covalent docking experiments and analysis online. The web server accepts the structures of both the ligand and the receptor uploaded by the user or retrieved from online databases with valid access id. It identifies the potential covalent binding patterns, carries out the covalent docking experiments and provides visualization of the result for user analysis. This web server is free and open to all users at http://docking.sce.ntu.edu.sg/.

  15. Docking to flexible nicotinic acetylcholine receptors

    DEFF Research Database (Denmark)

    Sander, Tommy; Bruun, Anne T; Balle, Thomas

    2010-01-01

    Computational docking to nicotinic acetylcholine receptors (nAChRs) and other members of the Cys-loop receptor family is complicated by the flexibility of the so-called C-loop. As observed in the large number of published crystal structures of the acetylcholine binding protein (AChBP), a structural...

  16. Compodock, a new device for sterile docking

    NARCIS (Netherlands)

    van der Meer, P. F.; Biekart, F. T.; Pietersz, R. N.; Rebers, S. P.; Reesink, H. W.

    2000-01-01

    BACKGROUND: A new device for sterile docking, the Compodock (Fresenius NPBI Transfusion Technology), was developed for connecting PVC tubing for medical use while maintaining sterility. STUDY DESIGN AND METHODS: Sterility of the connections was assessed by welding tubing with a heavy exterior

  17. Solvated protein-DNA docking using HADDOCK

    NARCIS (Netherlands)

    van Dijk, Marc; Visscher, Koen M; Bonvin, Alexandre M.J.J; Kastritis, Panagiotis L.

    2013-01-01

    Interfacial water molecules play an important role in many aspects of protein-DNA specificity and recognition. Yet they have been mostly neglected in the computational modeling of these complexes. We present here a solvated docking protocol that allows explicit inclusion of water molecules in the

  18. [Relationship between the prone position and achieving head control at 3 months].

    Science.gov (United States)

    Pérez-Machado, J L; Rodríguez-Fuentes, G

    2013-10-01

    Owing to the significant increase of mild motor delays and the strong intolerance of infants to be placed on prone position observed in the Physiotherapy Unit of the Maternal and Children's University Hospital of the Canaries (HUMIC), a study was conducted to determine whether positioning infants in the prone position while awake affected the achievement and quality of head control at three months. A prospective comparative practice-based study of a representative sample of 67 healthy infants born in the HUMIC, and divided into an experimental group (n = 35) and control group (n = 32). The Alberta Infant Motor Scale (AIMS) and a parent questionnaire were used as measurement tools. The intervention consisted of regular home visits to the experimental group (from the first to the third month). The two groups were evaluated in their homes at the end of 3 months. The differences in mean raw score of the AIMS at 3 months were, 16.26 in the experimental group and 10.38 in control group (P<.001). The percentile mean was 94 in the experimental group, and less than 50 (42) in the control group. All of the experimental group babies achieved the head control, with only 8 in the control group (25%). The significant findings suggest a direct relationship between the time spent in the prone position when the baby is awake and the achievement of head control at three months. Copyright © 2012 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

  19. Positioning of sensors for control of ventilation systems in broiler houses: a case study

    Directory of Open Access Journals (Sweden)

    Thayla Morandi Ridolfi de Carvalho Curi

    Full Text Available ABSTRACT Ventilation systems are incorporated at intensive poultry farms to control environment conditions and thermal comfort of broilers. The ventilation system operates based on environmental data, particularly measured by sensors of temperature and relative humidity. Sensors are placed at different positions of the facility. Quality, number and positioning of the sensors are critical factors to achieve an efficient performance of the system. For this reason, a strategic positioning of the sensors associated to controllers could support the maintenance and management of the microclimate inside the facility. This research aims to identify the three most representative points for the positioning of sensors in order to support the ventilation system during the critical period from 12h00 to 15h00 on summer days. Temperature, relative humidity and wind speed were measured in four different tunnel ventilated barns at the final stage of the production cycle. The descriptive analysis was performed on these data. The Temperature and Humidity Index (THI was also calculated. Then, the geostatistical analysis of THI was performed by GS+ and the position of sensors was determined by ordinary kriging. The methodology was able to detect the most representative points for the positioning of sensors in a case study (southeastern Brazil. The results suggested that this strategic positioning would help controllers to obtain a better inference of the microclimate during the studied period (the hottest microclimate, considered critical in Brazil. In addition, these results allow developing a future road map for a decision support system based on 24 h monitoring of the ventilation systems in broiler houses.

  20. Pull-pull position control of dual motor wire rope transmission.

    Science.gov (United States)

    Guo, Quan; Jiao, Zongxia; Yan, Liang; Yu, Qian; Shang, Yaoxing

    2016-08-01

    Wire rope transmission is very efficient because of the small total moving object mass. The wire rope could only transmit pulling force. Therefore it has to be kept in a tightened state during transmission; in high speed applications the dynamic performance depends on the rope's stiffness, which can be adjusted by the wire rope tension. To improve the system dynamic performance output, this paper proposes a novel pull-pull method based on dual motors connected by wire ropes, for precise, high speed position control applications. The method can regulate target position and wire rope tension simultaneously. Wire ropes remain in a pre-tightening state at all times, which prevents the influence of elasticity and reduces the position tracking error in the changing direction process. Simulations and experiments were conducted; the results indicate that both position precision and superior dynamic performance can be synchronously achieved. The research is relevant to space craft precision pointing instruments.

  1. Membrane tension controls adhesion positioning at the leading edge of cells.

    Science.gov (United States)

    Pontes, Bruno; Monzo, Pascale; Gole, Laurent; Le Roux, Anabel-Lise; Kosmalska, Anita Joanna; Tam, Zhi Yang; Luo, Weiwei; Kan, Sophie; Viasnoff, Virgile; Roca-Cusachs, Pere; Tucker-Kellogg, Lisa; Gauthier, Nils C

    2017-09-04

    Cell migration is dependent on adhesion dynamics and actin cytoskeleton remodeling at the leading edge. These events may be physically constrained by the plasma membrane. Here, we show that the mechanical signal produced by an increase in plasma membrane tension triggers the positioning of new rows of adhesions at the leading edge. During protrusion, as membrane tension increases, velocity slows, and the lamellipodium buckles upward in a myosin II-independent manner. The buckling occurs between the front of the lamellipodium, where nascent adhesions are positioned in rows, and the base of the lamellipodium, where a vinculin-dependent clutch couples actin to previously positioned adhesions. As membrane tension decreases, protrusion resumes and buckling disappears, until the next cycle. We propose that the mechanical signal of membrane tension exerts upstream control in mechanotransduction by periodically compressing and relaxing the lamellipodium, leading to the positioning of adhesions at the leading edge of cells. © 2017 Pontes et al.

  2. Global stabilisation of large-scale hydraulic networks with quantised and positive proportional controls

    DEFF Research Database (Denmark)

    Jensen, Tom Nørgaard; Wisniewski, Rafal

    2013-01-01

    a set of decentralised, logarithmic quantised and constrained control actions with properly designed quantisation parameters. That is, an attractor set with a compact basin of attraction exists. Subsequently, the basin can be increased by increasing the control gains. In our work, this result...... is extended by showing that an attractor set with a global basin of attraction exists for arbitrary values of positive control gains, given that the upper level of the quantiser is properly designed. Furthermore, the proof is given for general monotone quantisation maps. Since the basin of attraction...

  3. Guaranteed Cost Finite-Time Control of Fractional-Order Positive Switched Systems

    Directory of Open Access Journals (Sweden)

    Leipo Liu

    2017-01-01

    Full Text Available The problem of guaranteed cost finite-time control of fractional-order positive switched systems (FOPSS is considered in this paper. Firstly, a new cost function is defined. Then, by constructing linear copositive Lyapunov functions and using the average dwell time (ADT approach, a state feedback controller and a static output feedback controller are constructed, respectively, and sufficient conditions are derived to guarantee that the corresponding closed-loop systems are guaranteed cost finite-time stable (GCFTS. Such conditions can be easily solved by linear programming. Finally, two examples are given to illustrate the effectiveness of the proposed method.

  4. Positive and Negative Perfectionism in Migrainus Patients Compaired with Control Group

    Directory of Open Access Journals (Sweden)

    H Afshar

    2008-01-01

    Full Text Available ABSTRACT: Introduction & Objective: The positive and negative effects of perfectionism on human cognition, affection and behavior have been emphasized. Perfectionism has been conceptualized as a multidimensional construct, with both adaptive and maladaptive aspects, which is one of the common personality traits that cause lifelong stress in human and results in anxiety, depression and physical and mental distress.The aim of this study was to assess the positive and negative perfectionism in migrainus patients in comparison with control group. Materials & Methods: This is an analytical (Case-control study which was performed on 91 migraine patients and 88 healthy individuals. The pqtients and controls completed a standard 40 item questionnaire for perfectionism – PANPS (20 for positive and 20 for negative perfectionism . The patients in both groups were matched for gender and age. Mean of positive and negative perfectionism scores for two groups was statistically analysed using SPSS software. Results: Mean positive perfectionism score was 83.47±8.5 for migraine group and 65.47±7.54 for control group (p=0.0001. The difference between two groups was significant. Mean of negative perfectionism score was 74.12±10.6 for migraine group and 51.79±7.8 for control group(p=0.0001. Conclusion: The results show that migraine patients have higher mean of perfectionism scores than healthy individuals. Based on this study and other clinical experiences more attention to psychotherapy is necessary for better management of migraine and recognition of personality profile in migraine patient helps to reduce patient’s complaints.

  5. Asynchronous L1-gain control of uncertain switched positive linear systems with dwell time.

    Science.gov (United States)

    Li, Yang; Zhang, Hongbin

    2018-04-01

    In this paper, dwell time (DT) stability, L 1 -gain performance analysis and asynchronous L 1 -gain controller design problems of uncertain switched positive linear systems (SPLSs) are investigated. Via a time-scheduled multiple linear co-positive Lyapunov function (TSMLCLF) approach, convex sufficient conditions of DT stability and L 1 -gain performance of SPLSs with interval and polytopic uncertainties are presented. Furthermore, by utilizing the feature that the TSMLCLF keeps decreasing even if the controller is running asynchronously with the system, the asynchronous L 1 -gain controller design problem of SPLSs with interval and polytopic uncertainties is investigated. Convex sufficient conditions of the existence of time-varying asynchronous state-feedback controller which can ensure the closed-loop system's positivity, stability and L 1 -gain performance are established, and the controller gain matrices can be calculated instantaneously online. The obtained L 1 -gain in the paper is standard. All the results are presented in terms of linear programming. A practical example is provided to show the effectiveness of the results. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  6. In silico predictive studies of mAHR congener binding using homology modelling and molecular docking.

    Science.gov (United States)

    Panda, Roshni; Cleave, A Suneetha Susan; Suresh, P K

    2014-09-01

    The aryl hydrocarbon receptor (AHR) is one of the principal xenobiotic, nuclear receptor that is responsible for the early events involved in the transcription of a complex set of genes comprising the CYP450 gene family. In the present computational study, homology modelling and molecular docking were carried out with the objective of predicting the relationship between the binding efficiency and the lipophilicity of different polychlorinated biphenyl (PCB) congeners and the AHR in silico. Homology model of the murine AHR was constructed by several automated servers and assessed by PROCHECK, ERRAT, VERIFY3D and WHAT IF. The resulting model of the AHR by MODWEB was used to carry out molecular docking of 36 PCB congeners using PatchDock server. The lipophilicity of the congeners was predicted using the XLOGP3 tool. The results suggest that the lipophilicity influences binding energy scores and is positively correlated with the same. Score and Log P were correlated with r = +0.506 at p = 0.01 level. In addition, the number of chlorine (Cl) atoms and Log P were highly correlated with r = +0.900 at p = 0.01 level. The number of Cl atoms and scores also showed a moderate positive correlation of r = +0.481 at p = 0.01 level. To the best of our knowledge, this is the first study employing PatchDock in the docking of AHR to the environmentally deleterious congeners and attempting to correlate structural features of the AHR with its biochemical properties with regards to PCBs. The result of this study are consistent with those of other computational studies reported in the previous literature that suggests that a combination of docking, scoring and ranking organic pollutants could be a possible predictive tool for investigating ligand-mediated toxicity, for their subsequent validation using wet lab-based studies. © The Author(s) 2012.

  7. AnchorDock for Blind Flexible Docking of Peptides to Proteins.

    Science.gov (United States)

    Slutzki, Michal; Ben-Shimon, Avraham; Niv, Masha Y

    2017-01-01

    Due to increasing interest in peptides as signaling modulators and drug candidates, several methods for peptide docking to their target proteins are under active development. The "blind" docking problem, where the peptide-binding site on the protein surface is unknown, presents one of the current challenges in the field. AnchorDock protocol was developed by Ben-Shimon and Niv to address this challenge.This protocol narrows the docking search to the most relevant parts of the conformational space. This is achieved by pre-folding the free peptide and by computationally detecting anchoring spots on the surface of the unbound protein. Multiple flexible simulated annealing molecular dynamics (SAMD) simulations are subsequently carried out, starting from pre-folded peptide conformations, constrained to the various precomputed anchoring spots.Here, AnchorDock is demonstrated using two known protein-peptide complexes. A PDZ-peptide complex provides a relatively easy case due to the relatively small size of the protein, and a typical peptide conformation and binding region; a more challenging example is a complex between USP7 N-term and a p53-derived peptide, where the protein is larger, and the peptide conformation and a binding site are generally assumed to be unknown. AnchorDock returned native-like solutions ranked first and third for the PDZ and USP7 complexes, respectively. We describe the procedure step by step and discuss possible modifications where applicable.

  8. Approximation-Based Discrete-Time Adaptive Position Tracking Control for Interior Permanent Magnet Synchronous Motors.

    Science.gov (United States)

    Yu, Jinpeng; Shi, Peng; Yu, Haisheng; Chen, Bing; Lin, Chong

    2015-07-01

    This paper considers the problem of discrete-time adaptive position tracking control for a interior permanent magnet synchronous motor (IPMSM) based on fuzzy-approximation. Fuzzy logic systems are used to approximate the nonlinearities of the discrete-time IPMSM drive system which is derived by direct discretization using Euler method, and a discrete-time fuzzy position tracking controller is designed via backstepping approach. In contrast to existing results, the advantage of the scheme is that the number of the adjustable parameters is reduced to two only and the problem of coupling nonlinearity can be overcome. It is shown that the proposed discrete-time fuzzy controller can guarantee the tracking error converges to a small neighborhood of the origin and all the signals are bounded. Simulation results illustrate the effectiveness and the potentials of the theoretic results obtained.

  9. The Influence of PZT Actuators Positioning in Active Structural Acoustic Control

    Directory of Open Access Journals (Sweden)

    P. Švec

    2007-01-01

    Full Text Available This paper deals with the effect of secondary actuator positioning in an active structural acoustics control (ASAC experiment. The ASAC approach is based on minimizing the sound radiation from structures to the far field by controlling the structural vibrations. In this article a rectangular steel plate structure was assumed with one secondary actuator attached to it. As a secondary actuator, a specially designed piezoelectric stripe actuator was used. We studied the effect of the position of the actuator on the pattern and on the radiated sound field of the structural vibration, with and without active control. The total radiated power was also measured. The experimental data was confronted with the results obtained by a numerical solution of the mathematical model used. For the solution, the finite element method in the ANSYS software package was used. 

  10. Position Control of Pneumatic Actuator Using Self-Regulation Nonlinear PID

    Directory of Open Access Journals (Sweden)

    Syed Najib Syed Salim

    2014-01-01

    Full Text Available The enhancement of nonlinear PID (N-PID controller for a pneumatic positioning system is proposed to improve the performance of this controller. This is executed by utilizing the characteristic of rate variation of the nonlinear gain that is readily available in N-PID controller. The proposed equation, namely, self-regulation nonlinear function (SNF, is used to reprocess the error signal with the purpose of generating the value of the rate variation, continuously. With the addition of this function, a new self-regulation nonlinear PID (SN-PID controller is proposed. The proposed controller is then implemented to a variably loaded pneumatic actuator. Simulation and experimental tests are conducted with different inputs, namely, step, multistep, and random waveforms, to evaluate the performance of the proposed technique. The results obtained have been proven as a novel initiative at examining and identifying the characteristic based on a new proposal controller resulting from N-PID controller. The transient response is improved by a factor of 2.2 times greater than previous N-PID technique. Moreover, the performance of pneumatic positioning system is remarkably good under various loads.

  11. An energy-saving nonlinear position control strategy for electro-hydraulic servo systems.

    Science.gov (United States)

    Baghestan, Keivan; Rezaei, Seyed Mehdi; Talebi, Heidar Ali; Zareinejad, Mohammad

    2015-11-01

    The electro-hydraulic servo system (EHSS) demonstrates numerous advantages in size and performance compared to other actuation methods. Oftentimes, its utilization in industrial and machinery settings is limited by its inferior efficiency. In this paper, a nonlinear backstepping control algorithm with an energy-saving approach is proposed for position control in the EHSS. To achieve improved efficiency, two control valves including a proportional directional valve (PDV) and a proportional relief valve (PRV) are used to achieve the control objectives. To design the control algorithm, the state space model equations of the system are transformed to their normal form and the control law through the PDV is designed using a backstepping approach for position tracking. Then, another nonlinear set of laws is derived to achieve energy-saving through the PRV input. This control design method, based on the normal form representation, imposes internal dynamics on the closed-loop system. The stability of the internal dynamics is analyzed in special cases of operation. Experimental results verify that both tracking and energy-saving objectives are satisfied for the closed-loop system. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  12. tDCS over the left prefrontal cortex enhances cognitive control for positive affective stimuli.

    Science.gov (United States)

    Vanderhasselt, Marie-Anne; De Raedt, Rudi; Brunoni, Andre R; Campanhã, Camila; Baeken, Chris; Remue, Jonathan; Boggio, Paulo S

    2013-01-01

    Transcranial Direct Current Stimulation (tDCS) is a neuromodulation technique with promising results for enhancing cognitive information processes. So far, however, research has mainly focused on the effects of tDCS on cognitive control operations for non-emotional material. Therefore, our aim was to investigate the effects on cognitive control considering negative versus positive material. For this sham-controlled, within-subjects study, we selected a homogeneous sample of twenty-five healthy participants. By using behavioral measures and event related potentials (ERP) as indexes, we aimed to investigate whether a single session of anodal tDCS of the left dorsolateral prefrontal cortex (DLPFC) would have specific effects in enhancing cognitive control for positive and negative valenced stimuli. After tDCS over the left DLPFC (and not sham control stimulation), we observed more negative N450 amplitudes along with faster reaction times when inhibiting a habitual response to happy compared to sad facial expressions. Gender did not influence the effects of tDCS on cognitive control for emotional information. In line with the Valence Theory of side-lateralized activity, this stimulation protocol might have led to a left dominant (relative to right) prefrontal cortical activity, resulting in augmented cognitive control specifically for positive relative to negative stimuli. To verify that tDCS induces effects that are in line with all aspects of the well known Valence Theory, future research should investigate the effects of tDCS over the left vs. right DLPFC on cognitive control for emotional information.

  13. tDCS over the left prefrontal cortex enhances cognitive control for positive affective stimuli.

    Directory of Open Access Journals (Sweden)

    Marie-Anne Vanderhasselt

    Full Text Available Transcranial Direct Current Stimulation (tDCS is a neuromodulation technique with promising results for enhancing cognitive information processes. So far, however, research has mainly focused on the effects of tDCS on cognitive control operations for non-emotional material. Therefore, our aim was to investigate the effects on cognitive control considering negative versus positive material. For this sham-controlled, within-subjects study, we selected a homogeneous sample of twenty-five healthy participants. By using behavioral measures and event related potentials (ERP as indexes, we aimed to investigate whether a single session of anodal tDCS of the left dorsolateral prefrontal cortex (DLPFC would have specific effects in enhancing cognitive control for positive and negative valenced stimuli. After tDCS over the left DLPFC (and not sham control stimulation, we observed more negative N450 amplitudes along with faster reaction times when inhibiting a habitual response to happy compared to sad facial expressions. Gender did not influence the effects of tDCS on cognitive control for emotional information. In line with the Valence Theory of side-lateralized activity, this stimulation protocol might have led to a left dominant (relative to right prefrontal cortical activity, resulting in augmented cognitive control specifically for positive relative to negative stimuli. To verify that tDCS induces effects that are in line with all aspects of the well known Valence Theory, future research should investigate the effects of tDCS over the left vs. right DLPFC on cognitive control for emotional information.

  14. Design of Optimal Hybrid Position/Force Controller for a Robot Manipulator Using Neural Networks

    Directory of Open Access Journals (Sweden)

    Vikas Panwar

    2007-01-01

    Full Text Available The application of quadratic optimization and sliding-mode approach is considered for hybrid position and force control of a robot manipulator. The dynamic model of the manipulator is transformed into a state-space model to contain two sets of state variables, where one describes the constrained motion and the other describes the unconstrained motion. The optimal feedback control law is derived solving matrix differential Riccati equation, which is obtained using Hamilton Jacobi Bellman optimization. The optimal feedback control law is shown to be globally exponentially stable using Lyapunov function approach. The dynamic model uncertainties are compensated with a feedforward neural network. The neural network requires no preliminary offline training and is trained with online weight tuning algorithms that guarantee small errors and bounded control signals. The application of the derived control law is demonstrated through simulation with a 4-DOF robot manipulator to track an elliptical planar constrained surface while applying the desired force on the surface.

  15. Relative position control design of receiver UAV in flying-boom aerial refueling phase.

    Science.gov (United States)

    An, Shuai; Yuan, Suozhong

    2018-02-01

    This paper proposes the design of the relative position-keeping control of the receiver unmanned aerial vehicle (UAV) with the time-varying mass in the refueling phase utilizing an inner-outer loop structure. Firstly, the model of the receiver in the refueling phase is established. And then tank model is set up to analyze the influence of fuel transfer on the receiver. Subsequently, double power reaching law based sliding mode controller is designed to control receiver translational motion relative to tanker aircraft in the outer loop while active disturbance rejection control technique is applied to the inner loop to stabilize the receiver. In addition, the closed-loop stabilities of the subsystems are established, respectively. Finally, an aerial refueling model under various refueling strategies is utilized. Simulations and comparative analysis demonstrate the effectiveness and robustness of the proposed controllers. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Beam position monitor multiplexer controller upgrade at the LAMPF proton storage ring

    International Nuclear Information System (INIS)

    Scarborough, W.K.; Cohen, S.

    1992-01-01

    The beam position monitor (BPM) is one of the primary diagnostic tools used for the tuning of the proton storage ring (PSR) at the Clinton P. Anderson Meson Physics Facility (LAMPF). A replacement for the existing, monolithic, wire-wrapped microprocessor-based BPM multiplexer controller has been built. The controller has been redesigned as a modular system retaining the same functionality of the original system built in 1981. Individual printed circuit cards are used for each controller function to insure greater maintainability and ease of keeping a spare parts inventory. Programmable logic device technology has substantially reduced the component count of the new controller. Diagnostic software was written to support the development of the upgraded controller. The new software actually uncovered some flaws in the original CAMAC interface. (author)

  17. Position control of an electro-pneumatic system based on PWM technique and FLC.

    Science.gov (United States)

    Najjari, Behrouz; Barakati, S Masoud; Mohammadi, Ali; Futohi, Muhammad J; Bostanian, Muhammad

    2014-03-01

    In this paper, modeling and PWM based control of an electro-pneumatic system, including the four 2-2 valves and a double acting cylinder are studied. Dynamic nonlinear behavior of the system, containing fast switching solenoid valves and a pneumatic cylinder, as well as electrical, magnetic, mechanical, and fluid subsystems are modeled. A DC-DC power converter is employed to improve solenoid valve performance and suppress system delay. Among different position control methods, a proportional integrator derivative (PID) controller and fuzzy logic controller (FLC) are evaluated. An experimental setup, using an AVR microcontroller is implemented. Simulation and experimental results verify the effectiveness of the proposed control strategies. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Improving tokamak vertical position control in the presence of power supply voltage saturation

    International Nuclear Information System (INIS)

    Favez, J-Y; Lister, J B; Muellhaupt, Ph; Srinivasan, B

    2005-01-01

    The control of the current, position and shape of an elongated cross-section tokamak plasma is complicated by the so-called instability of the current vertical position. Linearized models all share the feature of a single unstable eigenmode, attributable to this vertical instability of the plasma equilibrium movement, and a large number of stable or marginally stable eigenmodes, attributable to zero or positive resistance in all other model circuit equations. Due to the size and therefore cost of the ITER tokamak, there will naturally be smaller margins in the poloidal field coil power supplies, implying that the feedback control will experience actuator saturation during large transients due to a variety of plasma disturbances. Current saturation is relatively benign, due to the integrating nature of the tokamak, resulting in a reasonable time horizon for strategically handling the approach to saturation which leads to the loss of one degree of freedom in the feedback control for each saturated coil. On the other hand, voltage saturation is produced by the feedback controller itself, with no intrinsic delay. This paper presents a feedback controller design approach which explicitly takes saturation of the power supply voltage into account when producing the power supply demand signals. We consider the vertically stabilizing part of the ITER controller (fast controller) with one power supply and therefore a single saturated input. We consider an existing ITER controller and enlarge its region of attraction to the full null controllable region by adding a continuous nonlinearity into the control. In a system with a single unstable eigenmode and a single stable eigenmode we have already provided a proof of the asymptotical stability of the closed loop system, and we have examined the performance of this new continuous nonlinear controller. We have subsequently extended this analysis to a system with a single eigenmode and multiple stable eigenmodes. The method

  19. Medicinal plant phytochemicals and their inhibitory activities against pancreatic lipase: molecular docking combined with molecular dynamics simulation approach

    OpenAIRE

    Ahmed, Bilal; Ali Ashfaq, Usman; Mirza, Muhammad Usman

    2017-01-01

    Obesity is the worst health risk worldwide, which is linked to a number of diseases. Pancreatic lipase is considered as an affective cause of obesity and can be a major target for controlling the obesity. The present study was designed to find out best phytochemicals against pancreatic lipase through molecular docking combined with molecular dynamics (MD) simulation. For this purpose, a total of 3770 phytochemicals were docked against pancreatic lipase and ranked them on the basis of binding ...

  20. Kept in His Care: The Role of Perceived Divine Control in Positive Reappraisal Coping

    Directory of Open Access Journals (Sweden)

    Reed T. DeAngelis

    2017-07-01

    Full Text Available A formidable body of literature suggests that numerous dimensions of religious involvement can facilitate productive coping. One common assumption in this field is that religious worldviews provide overarching frameworks of meaning by which to positively reinterpret stressors. The current study explicitly tests this assumption by examining whether perceived divine control—i.e., the notion that God controls the course and direction of one’s life—buffers the adverse effects of recent traumatic life events on one’s capacity for positive reappraisal coping. We analyze cross-sectional survey data from Vanderbilt University’s Nashville Stress and Health Study (2011–2014, a probability sample of non-Hispanic black and white adults aged 22 to 69 living in Davidson County, Tennessee (n = 1252. Findings from multivariate regression models confirm: (1 there was an inverse association between past-year traumatic life events and positive reappraisals; but (2 perceived divine control significantly attenuated this inverse association. Substantively, our findings suggest that people who believe God controls their life outcomes are better suited for positively reinterpreting traumatic experiences. Implications, limitations, and avenues for future research are discussed.

  1. On Position Sensorless Control for Permanent Magnet Synchronous Motor Based on a New Sliding Mode Observer

    Directory of Open Access Journals (Sweden)

    Qixin Zhu

    2014-10-01

    Full Text Available For the problems of buffeting and phase delay in traditional rotor detection in sensorless vector control of permanent magnet synchronous motor (PMSM, the Sigmoid function is proposed to replace sign function and the approach of piecewise linearization is proposed to compensate phase delay. To the problem that the output of traditional low pass filter contains high- order harmonic, two-stage filter including traditional low-pass filter and Kalman filter is proposed in this paper. Based on the output of traditional first-order low-pass filter, the Kalman filter is used to get modified back-EMF. The phase-locked loop control of rotor position is adopted to estimate motor position and speed. A Matlab/Simulink simulation model of PMSM position servo control system is established. The simulation analysis of the new sliding mode observer’s back-EMF detection, position and speed estimation, load disturbance and dynamic process are carried out respectively. Simulation results verify feasibility of the new sliding mode observer algorithm.

  2. 对接机构分系统研制%Development of Docking Subsystem

    Institute of Scientific and Technical Information of China (English)

    陈宝东; 郑云青; 邵济明; 陈萌

    2011-01-01

    The composition, control scheduling, design, and reliability and safety of the docking subsystem of China's Shenzhou-8 spaceship and Tiangong-1 target spacecraft were introduced in this paper. The key technologies of the general design, dynamic simulation, test and important part design in the design of the docking subsystem were given out. The tests, such as the general characteristic test, docking and separating test, docking test system in thermal vacuum, and life test, and test results were presented briefly. The whole research phase of the docking subsystem was reviewed.%介绍了我国神舟八号飞船和天宫一号目标飞行器对接试验的对接机构分系统的组成、控制时序、设计方案,以及可靠性与安全性。给出了对接机构分系统研制中总体设计、动力学仿真、试验和关键部件研制等关键技术,以及整机特性测试、连接分离试验、热真空对接与分离试验、寿命试验等验证情况。回顾了对接机构分系统的研制过程。

  3. Assessment of Motor Control during Three-Dimensional Movements Tracking with Position-Varying Gravity Compensation

    Directory of Open Access Journals (Sweden)

    Yao Huang

    2017-05-01

    Full Text Available Active movements are important in the rehabilitation training for patients with neurological motor disorders, while weight of upper limb impedes movements due to muscles weakness. The objective of this study is to develop a position-varying gravity compensation strategy for a cable-based rehabilitation robot. The control strategy can estimate real-time gravity torque according to position feedback. Then, the performance of this control strategy was compared with the other two kinds of gravity compensation strategies (i.e., without compensation and with fixed compensation during movements tracking. Seven healthy subjects were invited to conduct tracking tasks along four different directions (i.e., upward, forward, leftward, and rightward. The performance of movements with different compensation strategies was compared in terms of root mean square error (RMSE between target and actual moving trajectories, normalized jerk score (NJS, mean velocity ratio (MVR of main motion direction, and the activation of six muscles. The results showed that there were significant effects in control strategies in all four directions with the RMSE and NJS values in the following order: without compensation > fixed compensation > position-varying compensation and MVR values in the following order: without compensation < fixed compensation < position-varying compensation (p < 0.05. Comparing with movements without compensation in all four directions, the activation of muscles during movements with position-varying compensation showed significant reductions, except the activations of triceps and in forward and leftward movements, the activations of upper trapezius and middle parts of deltoid in upward movements and the activations of posterior parts of deltoid in all four directions (p < 0.05. Therefore, with position-varying gravity compensation, the upper limb cable-based rehabilitation robotic system might assist subjects to perform movements with higher quality and

  4. Longitudinal investigation on learned helplessness tested under negative and positive reinforcement involving stimulus control.

    Science.gov (United States)

    Oliveira, Emileane C; Hunziker, Maria Helena

    2014-07-01

    In this study, we investigated whether (a) animals demonstrating the learned helplessness effect during an escape contingency also show learning deficits under positive reinforcement contingencies involving stimulus control and (b) the exposure to positive reinforcement contingencies eliminates the learned helplessness effect under an escape contingency. Rats were initially exposed to controllable (C), uncontrollable (U) or no (N) shocks. After 24h, they were exposed to 60 escapable shocks delivered in a shuttlebox. In the following phase, we selected from each group the four subjects that presented the most typical group pattern: no escape learning (learned helplessness effect) in Group U and escape learning in Groups C and N. All subjects were then exposed to two phases, the (1) positive reinforcement for lever pressing under a multiple FR/Extinction schedule and (2) a re-test under negative reinforcement (escape). A fourth group (n=4) was exposed only to the positive reinforcement sessions. All subjects showed discrimination learning under multiple schedule. In the escape re-test, the learned helplessness effect was maintained for three of the animals in Group U. These results suggest that the learned helplessness effect did not extend to discriminative behavior that is positively reinforced and that the learned helplessness effect did not revert for most subjects after exposure to positive reinforcement. We discuss some theoretical implications as related to learned helplessness as an effect restricted to aversive contingencies and to the absence of reversion after positive reinforcement. This article is part of a Special Issue entitled: insert SI title. Copyright © 2014. Published by Elsevier B.V.

  5. Enhancement of control rod drive mechanism seating position detector for JRR-3

    International Nuclear Information System (INIS)

    Ohuchi, Satoshi; Kurumada, Osamu; Kamiishi, Eigo; Sato, Masayuki; Ikekame, Yoshinori; Wada, Shigeru

    2016-06-01

    The purpose of the control rod drive mechanism seating position detector for JRR-3 is one of methods for confirming the shutdown condition of the reactor and sending out the seat position signal to other systems. The detector has been utilizing more than 25 years with maintenance regularly. However, some troubles occurred recently. Moreover, the detector has already been discontinued, and it is confirmed that the successor detector is unsuitable for the control rod drive mechanism of JRR-3. Therefore, it was necessary to select the adequate detector to the control rod drive mechanism of JRR-3. Accordingly, we built a test device with the aim of verifying several detectors for integrity and function. At the time of the test for performance confirmation, it was occurred unexpected problems. Nevertheless, we devise improvement of the problems and took measures. Thus we were able to make adequate detector for JRR-3 and replace to enhanced detector. This paper reports the Enhanced of Control rod drive mechanism seating position detector. (author)

  6. Review of the patient positioning reproducibility in head-and-neck radiotherapy using Statistical Process Control.

    Science.gov (United States)

    Moore, Sarah J; Herst, Patries M; Louwe, Robert J W

    2018-05-01

    A remarkable improvement in patient positioning was observed after the implementation of various process changes aiming to increase the consistency of patient positioning throughout the radiotherapy treatment chain. However, no tool was available to describe these changes over time in a standardised way. This study reports on the feasibility of Statistical Process Control (SPC) to highlight changes in patient positioning accuracy and facilitate correlation of these changes with the underlying process changes. Metrics were designed to quantify the systematic and random patient deformation as input for the SPC charts. These metrics were based on data obtained from multiple local ROI matches for 191 patients who were treated for head-and-neck cancer during the period 2011-2016. SPC highlighted a significant improvement in patient positioning that coincided with multiple intentional process changes. The observed improvements could be described as a combination of a reduction in outliers and a systematic improvement in the patient positioning accuracy of all patients. SPC is able to track changes in the reproducibility of patient positioning in head-and-neck radiation oncology, and distinguish between systematic and random process changes. Identification of process changes underlying these trends requires additional statistical analysis and seems only possible when the changes do not overlap in time. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Study of intelligent system for control of the tokamak-ETE plasma positioning

    International Nuclear Information System (INIS)

    Barbosa, Luis Filipe de Faria Pereira Wiltgen

    2003-01-01

    The development of an intelligent neural control system of the neural type, capable to perform real time control of the plasma displacement in the experiment tokamak spheric - ETE (spherical tokamak experiment ) is presented. The ETE machine is in operation since Nov 2000, in the LAP - Plasma Associated Laboratory of the Brazilian Institute on Spatial Research (INPE) in Sao Jose dos Campos, S P, Brazil. The experiment is dedicated to study the magnetic confinement of a fusion plasma in a configuration favorable for the construction of future reactors. Nuclear fusion constitutes a renewable energy source with low environmental impact, which uses atomic energy in pacific applications for the sustainable development of humanity. One of the important questions for the attainment of fusion relates to the stability of the plasma and control of its position during the reactor operation. Therefore, the development of systems to control the plasma in tokamaks constitutes a necessary technological advance for the feasibility of nuclear fusion. In particular, the research carried out in this thesis concerns the proposal of a system to control the vertical displacement of the plasma in the ETE tokamak, aiming to obtain steady pulses in this machine. A Magnetic Levitation system (Mag Lev) was developed as part of this work, allowing to study the nonlinear behavior of a device that, from the aspect of position control, is similar (analogous) to the plasma in the ETE tokamak, This magnetic levitation system was designed, mathematically modeled and built in order to test both classical and intelligent type controllers. The results of this comparison are very promising for the use of intelligent controllers in the ETE tokamak as well as other control applications. (author)

  8. Positive deviance as a strategy to prevent and control bloodstream infections in intensive care

    Directory of Open Access Journals (Sweden)

    Francimar Tinoco de Oliveira

    Full Text Available Abstract OBJECTIVE To describe the application of positive deviance as a strategy to prevent and control bloodstream infections. METHOD An intervention study with nursing and medical team members working in an intensive care unit in a university hospital, between June and December 2014. The four steps of the positive defiance methodology were applied: to define, to determine, to discover and to design. RESULTS In 90 days, 188 actions were observed, of these, 36.70% (n=69 were related to catheter dressing. In 81.15% (n=56 of these dressings, the professionals most adhered to the use of flexible sterile cotton-tipped swabs to perform antisepsis at catheter entry sites and fixation dressing. CONCLUSION Positive deviance contributed to the implementation of proposals to improve work processes and team development related to problems identified in central venous catheter care.

  9. Dynamics and feedback control of plasma equilibrium position in a tokamak

    International Nuclear Information System (INIS)

    Burenko, O.

    1983-01-01

    A brief history of the beginnings of nuclear fusion research involving toroidal closed-system magnetic plasma containment is presented. A tokamak machine is defined mathematically for the purposes of plasma equilibrium position perturbation analysis. The perturbation equations of a tokamak plasma equilibrium position are developed. Solution of the approximated perturbation equations is carried out. A unique, simple, and useful plasma displacement dynamics transfer function of a tokamak is developed. The dominant time constants of the dynamics transfer function are determined in a symbolic form. This symbolic form of the dynamics transfer function makes it possible to study the stability of a tokamak's plasma equilibrium position. Knowledge of the dynamics transfer function permits systematic syntheses of the required plasma displacement feedback control systems

  10. Robust H∞ Control of Neutral System with Time-Delay for Dynamic Positioning Ships

    Directory of Open Access Journals (Sweden)

    Dawei Zhao

    2015-01-01

    Full Text Available Due to the input time-delay existing in most thrust systems of the ships, the robust H∞ controller is designed for the ship dynamic positioning (DP system with time-delay. The input delay system is turned to a neutral time-delay system by a state-derivative control law. The less conservative result is derived for the neutral system with state-derivative feedback by the delay-decomposition approach and linear matrix inequality (LMI. Finally, the numerical simulations demonstrate the asymptotic stability and robustness of the controller and verify that the designed DP controller is effective in the varying environment disturbances of wind, waves, and ocean currents.

  11. Robust Hinfinity position control synthesis of an electro-hydraulic servo system.

    Science.gov (United States)

    Milić, Vladimir; Situm, Zeljko; Essert, Mario

    2010-10-01

    This paper focuses on the use of the techniques based on linear matrix inequalities for robust H(infinity) position control synthesis of an electro-hydraulic servo system. A nonlinear dynamic model of the hydraulic cylindrical actuator with a proportional valve has been developed. For the purpose of the feedback control an uncertain linearized mathematical model of the system has been derived. The structured (parametric) perturbations in the electro-hydraulic coefficients are taken into account. H(infinity) controller extended with an integral action is proposed. To estimate internal states of the electro-hydraulic servo system an observer is designed. Developed control algorithms have been tested experimentally in the laboratory model of an electro-hydraulic servo system. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

  12. An adaptive feedback controller for transverse angle and position jitter correction in linear particle beam accelerators

    International Nuclear Information System (INIS)

    Barr, D.S.

    1993-01-01

    It is desired to design a position and angle jitter control system for pulsed linear accelerators that will increase the accuracy of correction over that achieved by currently used standard feedback jitter control systems. Interpulse or pulse-to-pulse correction is performed using the average value of each macropulse. The configuration of such a system resembles that of a standard feedback correction system with the addition of an adaptive controller that dynamically adjusts the gain-phase contour of the feedback electronics. The adaptive controller makes changes to the analog feedback system between macropulses. A simulation of such a system using real measured jitter data from the Stanford Linear Collider was shown to decrease the average rms jitter by over two and a half times. The system also increased and stabilized the correction at high frequencies; a typical problem with standard feedback systems

  13. An adaptive feedback controller for transverse angle and position jitter correction in linear particle beam accelerators

    International Nuclear Information System (INIS)

    Barr, D.S.

    1992-01-01

    It is desired to design a position and angle jitter control system for pulsed linear accelerators that will increase the accuracy of correction over that achieved by currently used standard feedback jitter control systems. Interpulse or pulse-to-pulse correction is performed using the average value of each macropulse. The configuration of such a system resembles that of a standard feedback correction system with the addition of an adaptive controller that dynamically adjusts the gain-phase contour of the feedback electronics. The adaptive controller makes changes to the analog feedback system between macropulses. A simulation of such a system using real measured jitter data from the Stanford Linear Collider was shown to decrease the average rms jitter by over two and a half times. The system also increased and stabilized the correction at high frequencies; a typical problem with standard feedback systems

  14. Automated positioning dual-axis solar tracking system with precision elevation and azimuth angle control

    International Nuclear Information System (INIS)

    Sidek, M.H.M.; Azis, N.; Hasan, W.Z.W.; Ab Kadir, M.Z.A.; Shafie, S.; Radzi, M.A.M.

    2017-01-01

    This paper presents a study on an automated positioning open-loop dual-axis solar tracking system. The solar tracker was designed and fabricated using standard cylindrical aluminium hollow and Polyuthrene (PE). The control system of the solar tracker was governed by Micro Controller Unit (MCU) with auxiliary devices which includes encoder and Global Positioning System (GPS). The sun path trajectory algorithm utilizing the astronomical equation and GPS information was also embedded in the system. The power generation performance of the dual-axis solar tracking system was compared with the fixed-tilted Photovoltaic (PV) system. It is found that the solar tracker is able to position itself automatically based on sun path trajectory algorithm with an accuracy of ±0.5°. The embedded Proportional Integral Derivative (PID) positioning system improves the tracking of elevation and azimuth angles with minimum energy consumption. It is reveals that the proposed solar tracker is able generate 26.9% and 12.8% higher power than fixed-tilted PV system on a clear and heavy overcast conditions respectively. Overall, the open-loop dual-axis solar tracker can be deployed automatically at any location on the earth with minimal configurations and is suitable for mobile solar tracking system. - Highlights: • Self-positioning dual-axis solar tracking system. • Precise control of elevation and azimuth angle. • Sun path trajectory based on astronomical equation and GPS. • Can achieve up to 26.9% higher power than fixed-tilted PV system under clear weather condition.

  15. Optimal Control Method of Robot End Position and Orientation Based on Dynamic Tracking Measurement

    Science.gov (United States)

    Liu, Dalong; Xu, Lijuan

    2018-01-01

    In order to improve the accuracy of robot pose positioning and control, this paper proposed a dynamic tracking measurement robot pose optimization control method based on the actual measurement of D-H parameters of the robot, the parameters is taken with feedback compensation of the robot, according to the geometrical parameters obtained by robot pose tracking measurement, improved multi sensor information fusion the extended Kalan filter method, with continuous self-optimal regression, using the geometric relationship between joint axes for kinematic parameters in the model, link model parameters obtained can timely feedback to the robot, the implementation of parameter correction and compensation, finally we can get the optimal attitude angle, realize the robot pose optimization control experiments were performed. 6R dynamic tracking control of robot joint robot with independent research and development is taken as experimental subject, the simulation results show that the control method improves robot positioning accuracy, and it has the advantages of versatility, simplicity, ease of operation and so on.

  16. Neural correlates of preparatory and regulatory control over positive and negative emotion.

    Science.gov (United States)

    Seo, Dongju; Olman, Cheryl A; Haut, Kristen M; Sinha, Rajita; MacDonald, Angus W; Patrick, Christopher J

    2014-04-01

    This study used functional magnetic resonance imaging to investigate brain activation during preparatory and regulatory control while participants (N = 24) were instructed either to simply view or decrease their emotional response to, pleasant, neutral or unpleasant pictures. A main effect of emotional valence on brain activity was found in the right precentral gyrus, with greater activation during positive than negative emotion regulation. A main effect of regulation phase was evident in the bilateral anterior prefrontal cortex (PFC), precuneus, posterior cingulate cortex, right putamen and temporal and occipital lobes, with greater activity in these regions during preparatory than regulatory control. A valence X regulation interaction was evident in regions of ventromedial PFC and anterior cingulate cortex, reflecting greater activation while regulating negative than positive emotion, but only during active emotion regulation (not preparation). Conjunction analyses revealed common brain regions involved in differing types of emotion regulation including selected areas of left lateral PFC, inferior parietal lobe, temporal lobe, right cerebellum and bilateral dorsomedial PFC. The right lateral PFC was additionally activated during the modulation of both positive and negative valence. Findings demonstrate significant modulation of brain activity during both preparation for, and active regulation of positive and negative emotional states.

  17. Wideband Motion Control by Position and Acceleration Input Based Disturbance Observer

    Science.gov (United States)

    Irie, Kouhei; Katsura, Seiichiro; Ohishi, Kiyoshi

    The disturbance observer can observe and suppress the disturbance torque within its bandwidth. Recent motion systems begin to spread in the society and they are required to have ability to contact with unknown environment. Such a haptic motion requires much wider bandwidth. However, since the conventional disturbance observer attains the acceleration response by the second order derivative of position response, the bandwidth is limited due to the derivative noise. This paper proposes a novel structure of a disturbance observer. The proposed disturbance observer uses an acceleration sensor for enlargement of bandwidth. Generally, the bandwidth of an acceleration sensor is from 1Hz to more than 1kHz. To cover DC range, the conventional position sensor based disturbance observer is integrated. Thus, the performance of the proposed Position and Acceleration input based disturbance observer (PADO) is superior to the conventional one. The PADO is applied to position control (infinity stiffness) and force control (zero stiffness). The numerical and experimental results show viability of the proposed method.

  18. Zigbee networking technology and its application in Lamost optical fiber positioning and control system

    Science.gov (United States)

    Jin, Yi; Zhai, Chao; Gu, Yonggang; Zhou, Zengxiang; Gai, Xiaofeng

    2010-07-01

    4,000 fiber positioning units need to be positioned precisely in LAMOST(Large Sky Area Multi-object Optical Spectroscopic Telescope) optical fiber positioning & control system, and every fiber positioning unit needs two stepper motors for its driven, so 8,000 stepper motors need to be controlled in the entire system. Wireless communication mode is adopted to save the installing space on the back of the focal panel, and can save more than 95% external wires compared to the traditional cable control mode. This paper studies how to use the ZigBee technology to group these 8000 nodes, explores the pros and cons of star network and tree network in order to search the stars quickly and efficiently. ZigBee technology is a short distance, low-complexity, low power, low data rate, low-cost two-way wireless communication technology based on the IEEE 802.15.4 protocol. It based on standard Open Systems Interconnection (OSI): The 802.15.4 standard specifies the lower protocol layers-the physical layer (PHY), and the media access control (MAC). ZigBee Alliance defined on this basis, the rest layers such as the network layer and application layer, and is responsible for high-level applications, testing and marketing. The network layer used here, based on ad hoc network protocols, includes the following functions: construction and maintenance of the topological structure, nomenclature and associated businesses which involves addressing, routing and security and a self-organizing-self-maintenance functions which will minimize consumer spending and maintenance costs. In this paper, freescale's 802.15.4 protocol was used to configure the network layer. A star network and a tree network topology is realized, which can build network, maintenance network and create a routing function automatically. A concise tree network address allocate algorithm is present to assign the network ID automatically.

  19. Tungsten carbide-cobalt as a nanoparticulate reference positive control in in vitro genotoxicity assays.

    Science.gov (United States)

    Moche, Hélène; Chevalier, Dany; Barois, Nicolas; Lorge, Elisabeth; Claude, Nancy; Nesslany, Fabrice

    2014-01-01

    With the increasing human exposure to nanoparticles (NP), the evaluation of their genotoxic potential is of significant importance. However, relevance for NP of the routinely used in vitro genotoxicity assays is often questioned, and a nanoparticulate reference positive control would therefore constitute an important step to a better testing of NP, ensuring that test systems are really appropriate. In this study, we investigated the possibility of using tungsten carbide-cobalt (WC-Co) NP as reference positive control in in vitro genotoxicity assays, including 2 regulatory assays, the mouse lymphoma assay and the micronucleus assay, and in the Comet assay, recommended for the toxicological evaluation of nanomedicines by the French Agency of Human Health Products (Afssaps). Through these assays, we were able to study different genetic endpoints in 2 cell types commonly used in regulatory genotoxicity assays: the L5178Y mouse lymphoma cell line and primary cultures of human lymphocytes. Our results showed that the use of WC-Co NP as positive control in in vitro genotoxicity assays was conceivable, but that different parameters have to be considered, such as cell type and treatment schedule. L5178Y mouse lymphoma cells did not provide satisfactory results in the 3 performed tests. However, human lymphocytes were more sensitive to genotoxic effects induced by WC-Co NP, particularly after a 24-h treatment in the in vitro micronucleus assay and after a 4-h treatment in the in vitro Comet assay. Under such conditions, WC-Co could be used as a nanoparticulate reference positive control in these assays.

  20. The Marketing & Positive Impacts of Behavioral Control System on Societies & Countries

    OpenAIRE

    Ahmad Adel Mostafa; Ahmed Mohamed Tawfik

    2015-01-01

    Behavioral control systems are one of the most prominent tools used by managers and marketers for different internal and external purposes. One of the most important external purposes they have been used for is influencing consumer behavior. This paper explores the positive effects of implementing such systems on societies. It discusses consumer perception of the systems, their influence on their financial behavior in different contexts, how can they create order and how as well ...

  1. An Angular Method with Position Control for Block Mesh Squareness Improvement

    Energy Technology Data Exchange (ETDEWEB)

    Yao, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stillman, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-19

    We optimize a target function de ned by angular properties with a position control term for a basic stencil with a block-structured mesh, to improve element squareness in 2D and 3D. Comparison with the condition number method shows that besides a similar mesh quality regarding orthogonality can be achieved as the former does, the new method converges faster and provides a more uniform global mesh spacing in our numerical tests.

  2. Position, Attitude, and Fault-Tolerant Control of Tilting-Rotor Quadcopter

    Science.gov (United States)

    Kumar, Rumit

    The aim of this thesis is to present algorithms for autonomous control of tilt-rotor quadcopter UAV. In particular, this research work describes position, attitude and fault tolerant control in tilt-rotor quadcopter. Quadcopters are one of the most popular and reliable unmanned aerial systems because of the design simplicity, hovering capabilities and minimal operational cost. Numerous applications for quadcopters have been explored all over the world but very little work has been done to explore design enhancements and address the fault-tolerant capabilities of the quadcopters. The tilting rotor quadcopter is a structural advancement of traditional quadcopter and it provides additional actuated controls as the propeller motors are actuated for tilt which can be utilized to improve efficiency of the aerial vehicle during flight. The tilting rotor quadcopter design is accomplished by using an additional servo motor for each rotor that enables the rotor to tilt about the axis of the quadcopter arm. Tilting rotor quadcopter is a more agile version of conventional quadcopter and it is a fully actuated system. The tilt-rotor quadcopter is capable of following complex trajectories with ease. The control strategy in this work is to use the propeller tilts for position and orientation control during autonomous flight of the quadcopter. In conventional quadcopters, two propellers rotate in clockwise direction and other two propellers rotate in counter clockwise direction to cancel out the effective yawing moment of the system. The variation in rotational speeds of these four propellers is utilized for maneuvering. On the other hand, this work incorporates use of varying propeller rotational speeds along with tilting of the propellers for maneuvering during flight. The rotational motion of propellers work in sync with propeller tilts to control the position and orientation of the UAV during the flight. A PD flight controller is developed to achieve various modes of the

  3. The Drosophila DOCK family protein Sponge is required for development of the air sac primordium

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Kazushge; Anh Suong, Dang Ngoc; Yoshida, Hideki; Yamaguchi, Masamitsu, E-mail: myamaguc@kit.ac.jp

    2017-05-15

    Dedicator of cytokinesis (DOCK) family genes are known as DOCK1-DOCK11 in mammals. DOCK family proteins mainly regulate actin filament polymerization and/or depolymerization and are GEF proteins, which contribute to cellular signaling events by activating small G proteins. Sponge (Spg) is a Drosophila counterpart to mammalian DOCK3/DOCK4, and plays a role in embryonic central nervous system development, R7 photoreceptor cell differentiation, and adult thorax development. In order to conduct further functional analyses on Spg in vivo, we examined its localization in third instar larval wing imaginal discs. Immunostaining with purified anti-Spg IgG revealed that Spg mainly localized in the air sac primordium (ASP) in wing imaginal discs. Spg is therefore predicted to play an important role in the ASP. The specific knockdown of Spg by the breathless-GAL4 driver in tracheal cells induced lethality accompanied with a defect in ASP development and the induction of apoptosis. The monitoring of ERK signaling activity in wing imaginal discs by immunostaining with anti-diphospho-ERK IgG revealed reductions in the ERK signal cascade in Spg knockdown clones. Furthermore, the overexpression of D-raf suppressed defects in survival and the proliferation of cells in the ASP induced by the knockdown of Spg. Collectively, these results indicate that Spg plays a critical role in ASP development and tracheal cell viability that is mediated by the ERK signaling pathway. - Highlights: • Spg mainly localizes in the air sac primordium in wing imaginal discs. • Spg plays a critical role in air sac primordium development. • Spg positively regulates the ERK signal cascade.

  4. Molecular dynamics modeling the synthetic and biological polymers interactions pre-studied via docking

    Science.gov (United States)

    Tsvetkov, Vladimir B.; Serbin, Alexander V.

    2014-06-01

    In previous works we reported the design, synthesis and in vitro evaluations of synthetic anionic polymers modified by alicyclic pendant groups (hydrophobic anchors), as a novel class of inhibitors of the human immunodeficiency virus type 1 ( HIV-1) entry into human cells. Recently, these synthetic polymers interactions with key mediator of HIV-1 entry-fusion, the tri-helix core of the first heptad repeat regions [ HR1]3 of viral envelope protein gp41, were pre-studied via docking in terms of newly formulated algorithm for stepwise approximation from fragments of polymeric backbone and side-group models toward real polymeric chains. In the present article the docking results were verified under molecular dynamics ( MD) modeling. In contrast with limited capabilities of the docking, the MD allowed of using much more large models of the polymeric ligands, considering flexibility of both ligand and target simultaneously. Among the synthesized polymers the dinorbornen anchors containing alternating copolymers of maleic acid were selected as the most representative ligands (possessing the top anti-HIV activity in vitro in correlation with the highest binding energy in the docking). To verify the probability of binding of the polymers with the [HR1]3 in the sites defined via docking, various starting positions of polymer chains were tried. The MD simulations confirmed the main docking-predicted priority for binding sites, and possibilities for axial and belting modes of the ligands-target interactions. Some newly MD-discovered aspects of the ligand's backbone and anchor units dynamic cooperation in binding the viral target clarify mechanisms of the synthetic polymers anti-HIV activity and drug resistance prevention.

  5. Testing links between childhood positive peer relations and externalizing outcomes through a randomized controlled intervention study.

    Science.gov (United States)

    Witvliet, Miranda; van Lier, Pol A C; Cuijpers, Pim; Koot, Hans M

    2009-10-01

    In this study, the authors used a randomized controlled trial to explore the link between having positive peer relations and externalizing outcomes in 758 children followed from kindergarten to the end of 2nd grade. Children were randomly assigned to the Good Behavior Game (GBG), a universal classroom-based preventive intervention, or a control condition. Children's acceptance by peers, their number of mutual friends, and their proximity to others were assessed annually through peer ratings. Externalizing behavior was annually rated by teachers. Reductions in children's externalizing behavior and improvements in positive peer relations were found among GBG children, as compared with control-group children. Reductions in externalizing behavior appeared to be partly mediated by the improvements in peer acceptance. This mediating role of peer acceptance was found for boys only. The results suggest that positive peer relations are not just markers, but they are environmental mediators of boys' externalizing behavior development. Implications for research and prevention are discussed. (c) 2009 APA, all rights reserved.

  6. The Marketing & Positive Impacts of Behavioral Control System on Societies & Countries

    Directory of Open Access Journals (Sweden)

    Ahmad Adel Mostafa

    2015-03-01

    Full Text Available Behavioral control systems are one of the most prominent tools used by managers and marketers for different internal and external purposes. One of the most important external purposes they have been used for is influencing consumer behavior. This paper explores the positive effects of implementing such systems on societies. It discusses consumer perception of the systems, their influence on their financial behavior in different contexts, how can they create order and how as well as to what extent should it be implemented and finally how can minimize negative consumer behavior. A judgment based sample of typical consumers was surveyed using questionnaires for collecting primary data on these aspects. Secondary data from Egypt, Singapore and Malaysia was also used as an example of using behavioral control systems. Results show that consumers in general have a positive attitude towards imposing such systems. However, there were worries about misuse, abuse and overuse of theses systems’ policies. Consequently, data shows that behavioral control systems can positively enhance and influence consumer behavior as long as it is used to balance both consumer and retailer interests in a moderate, risk free manner.

  7. Modeling and controller design of a 6-DOF precision positioning system

    Science.gov (United States)

    Cai, Kunhai; Tian, Yanling; Liu, Xianping; Fatikow, Sergej; Wang, Fujun; Cui, Liangyu; Zhang, Dawei; Shirinzadeh, Bijan

    2018-05-01

    A key hurdle to meet the needs of micro/nano manipulation in some complex cases is the inadequate workspace and flexibility of the operation ends. This paper presents a 6-degree of freedom (DOF) serial-parallel precision positioning system, which consists of two compact type 3-DOF parallel mechanisms. Each parallel mechanism is driven by three piezoelectric actuators (PEAs), guided by three symmetric T-shape hinges and three elliptical flexible hinges, respectively. It can extend workspace and improve flexibility of the operation ends. The proposed system can be assembled easily, which will greatly reduce the assembly errors and improve the positioning accuracy. In addition, the kinematic and dynamic model of the 6-DOF system are established, respectively. Furthermore, in order to reduce the tracking error and improve the positioning accuracy, the Discrete-time Model Predictive Controller (DMPC) is applied as an effective control method. Meanwhile, the effectiveness of the DMCP control method is verified. Finally, the tracking experiment is performed to verify the tracking performances of the 6-DOF stage.

  8. Affective processing in positive schizotypy: Loose control of social-emotional information.

    Science.gov (United States)

    Papousek, Ilona; Weiss, Elisabeth M; Mosbacher, Jochen A; Reiser, Eva M; Schulter, Günter; Fink, Andreas

    2014-10-30

    Behavioral studies suggested heightened impact of emotionally laden perceptual input in schizophrenia spectrum disorders, in particular in patients with prominent positive symptoms. De-coupling of prefrontal and posterior cortices during stimulus processing, which is related to loosening of control of the prefrontal cortex over incoming affectively laden information, may underlie this abnormality. Pre-selected groups of individuals with low versus high positive schizotypy (lower and upper quartile of a large screening sample) were tested. During exposure to auditory displays of strong emotions (anger, sadness, cheerfulness), individuals with elevated levels of positive schizotypal symptoms showed lesser prefrontal-posterior coupling (EEG coherence) than their symptom-free counterparts (right hemisphere). This applied to negative emotions in particular and was most pronounced during confrontation with anger. The findings indicate a link between positive symptoms and a heightened impact particularly of threatening emotionally laden stimuli which might lead to exacerbation of positive symptoms and inappropriate behavior in interpersonal situations. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Informed cytology for triaging HPV-positive women: substudy nested in the NTCC randomized controlled trial.

    Science.gov (United States)

    Bergeron, Christine; Giorgi-Rossi, Paolo; Cas, Frederic; Schiboni, Maria Luisa; Ghiringhello, Bruno; Dalla Palma, Paolo; Minucci, Daria; Rosso, Stefano; Zorzi, Manuel; Naldoni, Carlo; Segnan, Nereo; Confortini, Massimo; Ronco, Guglielmo

    2015-02-01

    Human papillomavirus (HPV)-based screening needs triage. In most randomized controlled trials (RCTs) on HPV testing with cytological triage, cytology interpretation has been blind to HPV status. Women age 25 to 60 years enrolled in the New Technology in Cervical Cancer (NTCC) RCT comparing HPV testing with cytology were referred to colposcopy if HPV positive and, if no cervical intraepithelial neoplasia (CIN) was detected, followed up until HPV negativity. Cytological slides taken at the first colposcopy were retrieved and independently interpreted by an external laboratory, which was only aware of patients' HPV positivity. Sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values were computed for histologically proven CIN2+ with HPV status-informed cytology for women with a determination of atypical squamous cells of undetermined significance (ASCUS) or more severe. All statistical tests were two-sided. Among HPV-positive women, informed cytology had cross-sectional sensitivity, specificity, PPV and 1-NPV for CIN2+ of 85.6% (95% confidence interval [CI] = 76.6 to 92.1), 65.9% (95% CI = 63.1 to 68.6), 16.2% (95% CI = 13.0 to 19.8), and 1.7 (95% CI = 0.9 to 2.8), respectively. Cytology was also associated with subsequent risk of newly diagnosed CIN2+ and CIN3+. The cross-sectional relative sensitivity for CIN2+ vs blind cytology obtained by referring to colposcopy and following up only HPV positive women who had HPV status-informed cytology greater than or equal to ASCUS was 1.58 (95% CI = 1.22 to 2.01), while the corresponding relative referral to colposcopy was 0.95 (95% CI = 0.86 to 1.04). Cytology informed of HPV positivity is more sensitive than blind cytology and could allow longer intervals before retesting HPV-positive, cytology-negative women. © The Author 2015. Published by Oxford University Press.

  10. Prone position as prevention of lung injury in comatose patients: a prospective, randomized, controlled study.

    Science.gov (United States)

    Beuret, Pascal; Carton, Marie-Jose; Nourdine, Karim; Kaaki, Mahmoud; Tramoni, Gerard; Ducreux, Jean-Claude

    2002-05-01

    Comatose patients frequently exhibit pulmonary function worsening, especially in cases of pulmonary infection. It appears to have a deleterious effect on neurologic outcome. We therefore conducted a randomized trial to determine whether daily prone positioning would prevent lung worsening in these patients. Prospective, randomized, controlled study. Sixteen-bed intensive care unit. Fifty-one patients who required invasive mechanical ventilation because of coma with Glascow coma scores of 9 or less. In the prone position (PP) group: prone positioning for 4 h once daily until the patients could get up to sit in an armchair; in the supine position (SP) group: supine positioning. The primary end point was the incidence of lung worsening defined by an increase in the Lung Injury Score of at least 1 point since the time of randomization. The secondary end point was the incidence of ventilator-associated pneumonia (VAP). A total of 25 patients were randomly assigned to the PP group and 26 patients to the SP group. The characteristics of the patients from the two groups were similar at randomization. The incidence of lung worsening was lower in the PP group (12%) than in the SP group (50%) ( p=0.003). The incidence of VAP was 20% in the PP group and 38.4% in the SP group ( p=0.14). There was no serious complication attributable to prone positioning, however, there was a significant increase of intracranial pressure in the PP. In a selected population of comatose ventilated patients, daily prone positioning reduced the incidence of lung worsening.

  11. An information theory account of late frontoparietal ERP positivities in cognitive control.

    Science.gov (United States)

    Barceló, Francisco; Cooper, Patrick S

    2018-03-01

    ERP research on task switching has revealed distinct transient and sustained positive waveforms (latency circa 300-900 ms) while shifting task rules or stimulus-response (S-R) mappings. However, it remains unclear whether such switch-related positivities show similar scalp topography and index context-updating mechanisms akin to those posed for domain-general (i.e., classic P300) positivities in many task domains. To examine this question, ERPs were recorded from 31 young adults (18-30 years) while they were intermittently cued to switch or repeat their perceptual categorization of Gabor gratings varying in color and thickness (switch task), or else they performed two visually identical control tasks (go/no-go and oddball). Our task cueing paradigm examined two temporarily distinct stages of proactive rule updating and reactive rule execution. A simple information theory model helped us gauge cognitive demands under distinct temporal and task contexts in terms of low-level S-R pathways and higher-order rule updating operations. Task demands modulated domain-general (indexed by classic oddball P3) and switch positivities-indexed by both a cue-locked late positive complex and a sustained positivity ensuing task transitions. Topographic scalp analyses confirmed subtle yet significant split-second changes in the configuration of neural sources for both domain-general P3s and switch positivities as a function of both the temporal and task context. These findings partly meet predictions from information estimates, and are compatible with a family of P3-like potentials indexing functionally distinct neural operations within a common frontoparietal "multiple demand" system during the preparation and execution of simple task rules. © 2016 Society for Psychophysiological Research.

  12. Mapping with MAV: Experimental Study on the Contribution of Absolute and Relative Aerial Position Control

    Directory of Open Access Journals (Sweden)

    J. Skaloud

    2014-03-01

    Full Text Available This study highlights the benefit of precise aerial position control in the context of mapping using frame-based imagery taken by small UAVs. We execute several flights with a custom Micro Aerial Vehicle (MAV octocopter over a small calibration field equipped with 90 signalized targets and 25 ground control points. The octocopter carries a consumer grade RGB camera, modified to insure precise GPS time stamping of each exposure, as well as a multi-frequency/constellation GNSS receiver. The GNSS antenna and camera are rigidly mounted together on a one-axis gimbal that allows control of the obliquity of the captured imagery. The presented experiments focus on including absolute and relative aerial control. We confirm practically that both approaches are very effective: the absolute control allows omission of ground control points while the relative requires only a minimum number of control points. Indeed, the latter method represents an attractive alternative in the context of MAVs for two reasons. First, the procedure is somewhat simplified (e.g. the lever-arm between the camera perspective and antenna phase centers does not need to be determined and, second, its principle allows employing a single-frequency antenna and carrier-phase GNSS receiver. This reduces the cost of the system as well as the payload, which in turn increases the flying time.

  13. An Insight into the Anticancer Activities of Ru(II-Based Metallocompounds Using Docking Methods

    Directory of Open Access Journals (Sweden)

    Peter A. Ajibade

    2013-09-01

    Full Text Available Unlike organic molecules, reports on docking of metal complexes are very few; mainly due to the inadequacy of force fields in docking packages to appropriately characterize the metal atoms that consequentially hinder the rational design of metal-based drug complexes. In this study we have made used Molegro and Autodock to predict the anticancer activities of selected Ru(II complexes against twelve anticancer targets. We observed that introducing the quantum calculated atomic charges of the optimized geometries significantly improved the docking predictions of these anticancer metallocompounds. Despite several limitations in the docking of metal-based complexes, we obtained results that are highly correlated with the available experimental results. Most of our newly proposed metallocompounds are found theoretically to be better anticancer metallocompounds than all the experimentally proposed RAPTA complexes. An interesting features of a strong interactions of new modeled of metallocompounds against the two base edges of DNA strands suggest similar mechanisms of anticancer activities similar to that of cisplatin. There is possibility of covalent bonding between the metal center of the metallocompounds and the residues of the receptors DNA-1, DNA-2, HDAC7, HIS and RNR. However, the general results suggest the possibility of metals positioning the coordinated ligands in the right position for optimal receptor interactions and synergistic effects, rather than forming covalent bonds.

  14. Tobacco control and the World Trade Organization: mapping member states' positions after the framework convention on tobacco control.

    Science.gov (United States)

    Eckhardt, Jappe; Holden, Chris; Callard, Cynthia D

    2016-11-01

    To note the frequency of discussions and disputes about tobacco control measures at the World Trade Organization (WTO) before and after the coming into force of the Framework Convention on Tobacco Control (FCTC). To review trends or patterns in the positions taken by members of the WTO with respect to tobacco control measures. To discuss possible explanations for these observed trends/patterns. We gathered data on tobacco-related disputes in the WTO since its establishment in 1995 and its forerunner, the General Agreement on Tariffs and Trade (GATT), prior-FCTC and post-FCTC. We also looked at debates on tobacco control measures within the WTO more broadly. To this end, we classified and coded the positions of WTO member states during discussions on tobacco control and the FCTC, from 1995 until 2013, within the Technical Barriers to Trade (TBT) Committee and the Trade-Related Aspects of Intellectual Property Rights (TRIPS) Council. There is a growing interest within the WTO for tobacco-related issues and opposition to tobacco control measures is moving away from high-income countries towards low(er) income countries. The growing prominence of tobacco issues in the WTO can be attributed at least in part to the fact that during the past decade tobacco firms have been marginalised from the domestic policy-making process in many countries, which has forced them to look for other ways and forums to influence decision-making. Furthermore, the finding that almost all recent opposition within the WTO to stronger tobacco regulations came from developing countries is consistent with a relative shift of transnational tobacco companies' lobbying efforts from developed to developing countries. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  15. Scapular positioning and motor control in children and adults: a laboratory study using clinical measures.

    Science.gov (United States)

    Struyf, Filip; Nijs, Jo; Horsten, Stijn; Mottram, Sarah; Truijen, Steven; Meeusen, Romain

    2011-04-01

    The scapular muscular system is the major determinant of scapular positioning. In addition, strength and muscular endurance develops from childhood through adolescence. It is not known whether differences in scapular positioning and motor control between adults and children may exist. Ninety-two shoulders of 46 adults (mean = 39.4; 18-86 years; SD = 22.5), and 116 shoulders of 59 children (mean = 11.6; 6-17 years; SD = 3.5), were included in the study. Scapular positioning data were collected using a clinical assessment protocol including visual observation of titling and winging, measurement of forward shoulder posture, measurement of scapular upward rotation, and the Kinetic Medial Rotation Test (KMRT). The observation protocol for scapular winging and tilting did not show significant differences between adults and children. After controlling for height, forward shoulder posture (relaxed (0.28 cm/cm (0.06) vs. 0.31 cm/cm (0.07) and retracted (0.15 cm/cm (0.05) vs. 0.20 cm/cm (0.06)) were significantly smaller in children than in adults (P < 0.01). In addition, children showed greater scapular upward rotation (18.6°; SD 9.6°) than adults (14.5°; SD 10.9°) at 90° shoulder abduction. No significant differences were seen between children (19% positive test) and adults (24% positive test) using the KMRT. Children and adults show significant but small differences in scapular upward rotation and forward shoulder posture. These data provide useful reference values using a clinical protocol. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Reporting of Positive Results in Randomized Controlled Trials of Mindfulness-Based Mental Health Interventions.

    Directory of Open Access Journals (Sweden)

    Stephanie Coronado-Montoya

    Full Text Available A large proportion of mindfulness-based therapy trials report statistically significant results, even in the context of very low statistical power. The objective of the present study was to characterize the reporting of "positive" results in randomized controlled trials of mindfulness-based therapy. We also assessed mindfulness-based therapy trial registrations for indications of possible reporting bias and reviewed recent systematic reviews and meta-analyses to determine whether reporting biases were identified.CINAHL, Cochrane CENTRAL, EMBASE, ISI, MEDLINE, PsycInfo, and SCOPUS databases were searched for randomized controlled trials of mindfulness-based therapy. The number of positive trials was described and compared to the number that might be expected if mindfulness-based therapy were similarly effective compared to individual therapy for depression. Trial registries were searched for mindfulness-based therapy registrations. CINAHL, Cochrane CENTRAL, EMBASE, ISI, MEDLINE, PsycInfo, and SCOPUS were also searched for mindfulness-based therapy systematic reviews and meta-analyses.108 (87% of 124 published trials reported ≥1 positive outcome in the abstract, and 109 (88% concluded that mindfulness-based therapy was effective, 1.6 times greater than the expected number of positive trials based on effect size d = 0.55 (expected number positive trials = 65.7. Of 21 trial registrations, 13 (62% remained unpublished 30 months post-trial completion. No trial registrations adequately specified a single primary outcome measure with time of assessment. None of 36 systematic reviews and meta-analyses concluded that effect estimates were overestimated due to reporting biases.The proportion of mindfulness-based therapy trials with statistically significant results may overstate what would occur in practice.

  17. A 3D Printed Linear Pneumatic Actuator for Position, Force and Impedance Control

    Directory of Open Access Journals (Sweden)

    Jeremy Krause

    2018-05-01

    Full Text Available Although 3D printing has the potential to provide greater customization and to reduce the costs of creating actuators for industrial applications, the 3D printing of actuators is still a relatively new concept. We have developed a pneumatic actuator with 3D-printed parts and placed sensors for position and force control. So far, 3D printing has been used to create pneumatic actuators of the bellows type, thus having a limited travel distance, utilizing low pressures for actuation and being capable of only limited force production and response rates. In contrast, our actuator is linear with a large travel distance and operating at a relatively higher pressure, thus providing great forces and response rates, and this the main novelty of the work. We demonstrate solutions to key challenges that arise during the design and fabrication of 3D-printed linear actuators. These include: (1 the strategic use of metallic parts in high stress areas (i.e., the piston rod; (2 post-processing of the inner surface of the cylinder for smooth finish; (3 piston head design and seal placement for strong and leak-proof action; and (4 sensor choice and placement for position and force control. A permanent magnet placed in the piston head is detected using Hall effect sensors placed along the length of the cylinder to measure the position, and pressure sensors placed at the supply ports were used for force measurement. We demonstrate the actuator performing position, force and impedance control. Our work has the potential to open new avenues for creating less expensive, customizable and capable actuators for industrial and other applications.

  18. MAPPING GNSS RESTRICTED ENVIRONMENTS WITH A DRONE TANDEM AND INDIRECT POSITION CONTROL

    Directory of Open Access Journals (Sweden)

    E. Cledat

    2017-08-01

    Full Text Available The problem of autonomously mapping highly cluttered environments, such as urban and natural canyons, is intractable with the current UAV technology. The reason lies in the absence or unreliability of GNSS signals due to partial sky occlusion or multi-path effects. High quality carrier-phase observations are also required in efficient mapping paradigms, such as Assisted Aerial Triangulation, to achieve high ground accuracy without the need of dense networks of ground control points. In this work we consider a drone tandem in which the first drone flies outside the canyon, where GNSS constellation is ideal, visually tracks the second drone and provides an indirect position control for it. This enables both autonomous guidance and accurate mapping of GNSS restricted environments without the need of ground control points. We address the technical feasibility of this concept considering preliminary real-world experiments in comparable conditions and we perform a mapping accuracy prediction based on a simulation scenario.

  19. Global asymptotic stabilization of large-scale hydraulic networks using positive proportional controls

    DEFF Research Database (Denmark)

    Jensen, Tom Nørgaard; Wisniewski, Rafal

    2014-01-01

    An industrial case study involving a large-scale hydraulic network underlying a district heating system subject to structural changes is considered. The problem of controlling the pressure drop across the so-called end-user valves in the network to a designated vector of reference values under...... directional actuator constraints is addressed. The proposed solution consists of a set of decentralized positively constrained proportional control actions. The results show that the closed-loop system always has a globally asymptotically stable equilibrium point independently on the number of end......-users. Furthermore, by a proper design of controller gains the closed-loop equilibrium point can be designed to belong to an arbitrarily small neighborhood of the desired equilibrium point. Since there exists a globally asymptotically stable equilibrium point independently on the number of end-users in the system...

  20. Cervical Joint Position Sense in Hypobaric Conditions: A Randomized Double-Blind Controlled Trial.

    Science.gov (United States)

    Bagaianu, Diana; Van Tiggelen, Damien; Duvigneaud, N; Stevens, Veerle; Schroyen, Danny; Vissenaeken, Dirk; D'Hondt, Gino; Pitance, Laurent

    2017-09-01

    Well-adapted motor actions require intact and well-integrated information from all of the sensory systems, specifically the visual, vestibular, and somatosensory systems, including proprioception. Proprioception is involved in the sensorimotor control by providing the central nervous system with an updated body schema of the biomechanical and spatial properties of the body parts. With regard to the cervical spine, proprioceptive information from joint and muscle mechanoreceptors is integrated with vestibular and visual feedback to control head position, head orientation, and whole body posture. Postural control is highly complex and proprioception from joints is an important contributor to the system. Altitude has been used as a paradigm to study the mechanisms of postural control. Determining the mechanisms of postural control that are affected by moderate altitude is important as unpressurized aircrafts routinely operate at altitudes where hypoxia may be a concern. Deficits in motor performance arise when the reliance on proprioceptive feedback is abolished either experimentally or because of a disorder. As pilots require good neck motor control to counteract the weight of their head gear and proprioceptive information plays an important role in this process, the aim of this study was to determine if hypoxia at moderate altitudes would impair proprioception measured by joint position sense of the cervical spine in healthy subjects. Thirty-six healthy subjects (Neck Disability Index environment, a hypobaric chamber was used to simulate artificial moderate altitude. Head repositioning error was measured by asking the subject to perform a head-to-neutral task after submaximal flexion-extension and right/left rotation movements, and a head-to-target task, in which the subjects had to return to a 30° right and left rotation position. Exposure to artificial acute moderate altitude of 7,000 feet had no significant effects on cervical joint position sense measured by

  1. A dust-free dock

    Energy Technology Data Exchange (ETDEWEB)

    Merrion, D. [E & F Services Ltd. (United Kingdom)

    2002-10-01

    This paper describes the process of unloading coal, petcoke and other dusty products in environmentally-sensitive areas. It presents a case study of the deepwater Port of Foynes on the west coast of Ireland which imports animal feed, fertiliser, coal and cement clinker, where dockside mobile loaders (DMLs) have eliminated spillage and controlled dust, and a record case study of the Humber International Terminal in the UK, where air curtinas, dust suppression grids and EFFEX{reg_sign} filters overcome the dust problems. 2 photos.

  2. Enabling Spacecraft Formation Flying through Position Determination, Control and Enhanced Automation Technologies

    Science.gov (United States)

    Bristow, John; Bauer, Frank; Hartman, Kate; How, Jonathan

    2000-01-01

    Formation Flying is revolutionizing the way the space community conducts science missions around the Earth and in deep space. This technological revolution will provide new, innovative ways for the community to gather scientific information, share that information between space vehicles and the ground, and expedite the human exploration of space. Once fully matured, formation flying will result in numerous sciencecraft acting as virtual platforms and sensor webs, gathering significantly more and better science data than call be collected today. To achieve this goal, key technologies must be developed including those that address the following basic questions posed by the spacecraft: Where am I? Where is the rest of the fleet? Where do I need to be? What do I have to do (and what am I able to do) to get there? The answers to these questions and the means to implement those answers will depend oil the specific mission needs and formation configuration. However, certain critical technologies are common to most formations. These technologies include high-precision position and relative-position knowledge including Global Positioning System (GPS) mid celestial navigation; high degrees of spacecraft autonomy inter-spacecraft communication capabilities; targeting and control including distributed control algorithms, and high precision control thrusters and actuators. This paper provides an overview of a selection of the current activities NASA/DoD/Industry/Academia are working to develop Formation Flying technologies as quickly as possible, the hurdles that need to be overcome to achieve our formation flying vision, and the team's approach to transfer this technology to space. It will also describe several of the formation flying testbeds, such as Orion and University Nanosatellites, that are being developed to demonstrate and validate many of these innovative sensing and formation control technologies.

  3. The constrained control of force and position in multi-joint movements.

    Science.gov (United States)

    van Ingen Schenau, G J; Boots, P J; de Groot, G; Snackers, R J; van Woensel, W W

    1992-01-01

    In many arm or leg movements the hand or foot has to exert an external force on the environment. Based on an inverse dynamical analysis of cycling, it is shown that the distribution of net moments in the joints needed to control the direction of the external force is often opposite to the direction of joint displacements associated with this task. Kinetic and kinematic data were obtained from five experienced cyclists during ergometer cycling by means of film analysis and pedal force measurement. An inverse dynamic analysis, based on a linked segments model, yielded net joint moments, joint powers and muscle shortening velocities of eight leg muscles. Activation patterns of the muscles were obtained by means of surface electromyography. The results show that the transfer of rotations in hip, knee and ankle joints into the translation of the pedal is constrained by conflicting requirements. This occurs between the joint moments necessary to contribute to joint power and the moments necessary to establish a direction of the force on the pedal which allows this force to do work on the pedal. Co-activation of mono-articular agonists and their bi-articular antagonists appear to provide a unique solution for these conflicting requirements: bi-articular muscles appear to be able to control the desired direction of the external force on the pedal by adjusting the relative distribution of net moments over the joints while mono-articular muscles appear to be primarily activated when they are in the position to shorten and thus to contribute to positive work. Examples are given to illustrate the universal nature of this constrained control of force (external) and position (joint). Based on this study and published data it is suggested that different processes may underlie the organization of the control of mono- and bi-articular muscles.

  4. Relative position vectors: an alternative approach to conflict detection in air traffic control.

    Science.gov (United States)

    Vuckovic, Anita; Sanderson, Penelope; Neal, Andrew; Gaukrodger, Stephen; Wong, B L William

    2013-10-01

    We explore whether the visual presentation of relative position vectors (RPVs) improves conflict detection in conditions representing some aspects of future airspace concepts. To help air traffic controllers manage increasing traffic, new tools and systems can automate more cognitively demanding processes, such as conflict detection. However, some studies reveal adverse effects of such tools, such as reduced situation awareness and increased workload. New displays are needed that help air traffic controllers handle increasing traffic loads. A new display tool based on the display of RPVs, the Multi-Conflict Display (MCD), is evaluated in a series of simulated conflict detection tasks. The conflict detection performance of air traffic controllers with the MCD plus a conventional plan-view radar display is compared with their performance with a conventional plan-view radar display alone. Performance with the MCD plus radar was better than with radar alone in complex scenarios requiring controllers to find all actual or potential conflicts, especially when the number of aircraft on the screen was large. However performance with radar alone was better for static scenarios in which conflicts for a target aircraft, or target pair of aircraft, were the focus. Complementing the conventional plan-view display with an RPV display may help controllers detect conflicts more accurately with extremely high aircraft counts. We provide an initial proof of concept that RPVs may be useful for supporting conflict detection in situations that are partially representative of conditions in which controllers will be working in the future.

  5. Studies on preparation and adaptive thermal control performance of novel PTC (positive temperature coefficient) materials with controllable Curie temperatures

    International Nuclear Information System (INIS)

    Cheng, Wen-long; Yuan, Shuai; Song, Jia-liang

    2014-01-01

    PTC (positive temperature coefficient) material is a kind of thermo-sensitive material. In this study, a series of novel PTC materials adapted to thermal control of electron devices are prepared. By adding different low-melting-point blend matrixes into GP (graphite powder)/LDPE (low density polyethylene) composite, the Curie temperatures are adjusted to 9 °C, 25 °C, 34 °C and 41 °C, and the resistance–temperature coefficients are enhanced to 1.57/°C–2.15/°C. These PTC materials remain solid in the temperature region of PTC effect, which makes it possible to be used as heating element to achieve adaptive temperature control. In addition, the adaptive thermal control performances of this kind of materials are investigated both experimentally and theoretically. The result shows that the adaptive effect becomes more significant while the resistance–temperature coefficient increases. A critical heating power defined as the initial heating power which makes the equilibrium temperature reach terminal temperature is presented. The adaptive temperature control will be effective only if the initial power is below this value. The critical heating power is determined by the Curie temperature and resistance–temperature coefficient of PTC materials, and a higher Curie temperature or resistance–temperature coefficient will lead to a larger critical heating power. - Highlights: • A series of novel PTC (positive temperature coefficient) materials were prepared. • The Curie point of PTC material can be adjusted by choosing different blend matrixes. • The resistance–temperature coefficient of PTC materials is enhanced to 2.15/°C. • The material has good adaptive temperature control ability with no auxiliary method. • A mathematical model is established to analyze the performance and applicability

  6. Neural network control of focal position during time-lapse microscopy of cells.

    Science.gov (United States)

    Wei, Ling; Roberts, Elijah

    2018-05-09

    Live-cell microscopy is quickly becoming an indispensable technique for studying the dynamics of cellular processes. Maintaining the specimen in focus during image acquisition is crucial for high-throughput applications, especially for long experiments or when a large sample is being continuously scanned. Automated focus control methods are often expensive, imperfect, or ill-adapted to a specific application and are a bottleneck for widespread adoption of high-throughput, live-cell imaging. Here, we demonstrate a neural network approach for automatically maintaining focus during bright-field microscopy. Z-stacks of yeast cells growing in a microfluidic device were collected and used to train a convolutional neural network to classify images according to their z-position. We studied the effect on prediction accuracy of the various hyperparameters of the neural network, including downsampling, batch size, and z-bin resolution. The network was able to predict the z-position of an image with ±1 μm accuracy, outperforming human annotators. Finally, we used our neural network to control microscope focus in real-time during a 24 hour growth experiment. The method robustly maintained the correct focal position compensating for 40 μm of focal drift and was insensitive to changes in the field of view. About ~100 annotated z-stacks were required to train the network making our method quite practical for custom autofocus applications.

  7. Conceptual design of plasma position control of SST-1 tokamak using vertical field coil

    International Nuclear Information System (INIS)

    Gulati, Hitesh Kumar; Patel, Kiritkumar B.; Dhongde, Jasraj

    2015-01-01

    SST-1 (Steady State Superconducting Tokamak) is a plasma confinement device in Institute for Plasma Research (IPR) India. SST-1 has been commissioned successfully and has been carrying out plasma experiments since the beginning of 2014 achieved a maximum plasma current of 75 kA at a central field of 1.5 T and the plasma duration ∼ 500 ms. SST-1 looks forward to carrying out elongated plasma experiments and stretching plasma pulses beyond 1s. Based on the solution of Grad-Shafranov equation the shift of plasma column center from geometrical centre of vacuum chamber is measured using various magnetic probes and flux loops installed in the machine. The closed feedback loop uses plasma current (Ip), Delta R as feedback signal and manipulate the vertical field current (Ivf). The discharge starts with feed forward loop using initially provided reference then the active feedback starts after discharge by few msec once plasma column is completely formed. The feedback loop time is of the order of 10 msec. The primary objective is to acquire plasma position control related signals, compute plasma position and generate position correction signal for VF coil power supply, communicate correction to VF coil power supply and modify VF power supply output in a deterministic time span. In this we present the methodology used for plasma horizontal displacement control using vertical field and discuss the preliminary results. (author)

  8. Applying Positive Deviance for Improving Compliance to Adolescent Anemia Control Program in Tribal Communities of India.

    Science.gov (United States)

    Sethi, Vani; Sternin, Monique; Sharma, Deepika; Bhanot, Arti; Mebrahtu, Saba

    2017-09-01

    Positive deviance (PD) is an asset-based social and behavior change communication strategy, utilizing successful outliers within a specific context. It has been applied to tackling major public health problems but not adolescent anemia. The study, first of its kind, used PD to improve compliance to adolescent anemia control program in Jharkhand, India, where anemia prevalence in adolescent girls is 70%, and program compliance is low. With leadership of state government, the study was designed and implemented by a multidisciplinary 42 member PD team, in Khunti district, in 2014. Participatory appraisals were undertaken with 434 adolescent girls, 18 frontline workers, 15 teachers, and 751 community leaders/parents/relatives. Stakeholders were interviewed to identify positive deviants and PD determinants across 17 villages. Perceived benefits of iron folic acid tablet and nutritional care during adolescence are low. Positive deviants exist among adolescent girls (26 of 434), villages (2 of 17), and schools (2 of 17). Positive deviant adolescent girls consumed variety of iron-rich foods and in higher frequency, consumed iron folic acid tablets, and practiced recommended personal hygiene behaviors. Deviant practices in schools included supervision of students during tablet distribution among others. Government-led PD approach uncovered local solutions and provided a forum for government functionaries to listen to and dialogue with, and an opportunity to adapt the program according to the needs of the affected communities, who are missing partners in program design and management.

  9. Continuous positive airway pressure improves gait control in severe obstructive sleep apnoea: A prospective study.

    Directory of Open Access Journals (Sweden)

    Sébastien Baillieul

    Full Text Available Severe obstructive sleep apnoea (OSA can lead to neurocognitive alterations, including gait impairments. The beneficial effects of continuous positive airway pressure (CPAP on improving excessive daytime sleepiness and daily functioning have been documented. However, a demonstration of CPAP treatment efficacy on gait control is still lacking. This study aims to test the hypothesis that CPAP improves gait control in severe OSA patients.In this prospective controlled study, twelve severe OSA patients (age = 57.2±8.9 years, body mass index = 27.4±3.1 kg·m-2, apnoea-hypopnoea index = 46.3±11.7 events·h-1 and 10 healthy matched subjects were included. Overground gait parameters were recorded at spontaneous speed and stride time variability, a clinical marker of gait control, was calculated. To assess the role of executive functions in gait and postural control, a dual-task paradigm was applied using a Stroop test as secondary cognitive task. All assessments were performed before and after 8 weeks of CPAP treatment.Before CPAP treatment, OSA patients had significantly larger stride time variability (3.1±1.1% vs 2.1±0.5% and lower cognitive performances under dual task compared to controls. After CPAP treatment, stride time variability was significantly improved and no longer different compared to controls. Cognitive performance under dual task also improved after CPAP treatment.Eight weeks of CPAP treatment improves gait control of severe OSA patients, suggesting morphological and functional cerebral improvements. Our data provide a rationale for further mechanistic studies and the use of gait as a biomarker of OSA brain consequences.

  10. A process for providing positive primary control power by wind turbines

    Science.gov (United States)

    Marschner, V.; Michael, J.; Liersch, J.

    2014-12-01

    Due to the increasing share of wind energy in electricity generation, wind turbines have to fulfil additional requirements in the context of grid integration. The paper examines to which extent wind turbines can provide positive control power following the related grid code. The additional power has to be obtained from the rotating flywheel mass of the wind turbine's rotor. A simple physical model is developed that allows to draw conclusions about appropriate concepts by means of a dynamic simulation of the variables rotational speed, torque, power output and rotor power. The paper discusses scenarios to provide control power. The supply of control power at partial load is examined in detail using simulations. Under partial load conditions control power can be fed into the grid for a short time. Thereby the rotational speed drops so that aerodynamic efficiency decreases and feed-in power is below the initial value after the control process. In this way an unfavourable situation for the grid control is produced, therefore the paper proposes a modified partial load condition with a higher rotational speed. By providing primary control power the rotor is delayed to the optimum rotational speed so that more rotational energy can be fed in and fed-in power can be increased persistently. However, as the rotor does not operate at optimum speed, a small amount of the energy yield is lost. Finally, the paper shows that a wind farm can combine these two concepts: A part of the wind turbines work under modified partial load conditions can compensate the decrease of power of the wind turbines working under partial load conditions. Therefore the requested control power is provided and afterwards the original value of power is maintained.

  11. Controlling resonance energy transfer in nanostructure emitters by positioning near a mirror

    Science.gov (United States)

    Weeraddana, Dilusha; Premaratne, Malin; Gunapala, Sarath D.; Andrews, David L.

    2017-08-01

    The ability to control light-matter interactions in quantum objects opens up many avenues for new applications. We look at this issue within a fully quantized framework using a fundamental theory to describe mirror-assisted resonance energy transfer (RET) in nanostructures. The process of RET communicates electronic excitation between suitably disposed donor and acceptor particles in close proximity, activated by the initial excitation of the donor. Here, we demonstrate that the energy transfer rate can be significantly controlled by careful positioning of the RET emitters near a mirror. The results deliver equations that elicit new insights into the associated modification of virtual photon behavior, based on the quantum nature of light. In particular, our results indicate that energy transfer efficiency in nanostructures can be explicitly expedited or suppressed by a suitably positioned neighboring mirror, depending on the relative spacing and the dimensionality of the nanostructure. Interestingly, the resonance energy transfer between emitters is observed to "switch off" abruptly under suitable conditions of the RET system. This allows one to quantitatively control RET systems in a new way.

  12. Effects of sleeping position on back pain in physically active seniors: A controlled pilot study.

    Science.gov (United States)

    Desouzart, Gustavo; Matos, Rui; Melo, Filipe; Filgueiras, Ernesto

    2015-01-01

    The increase in life expectancy of elderly population has aroused the interest of different knowledge areas in understanding the variables that are involved in the aging process, linking them to other concepts such as active aging, healthy aging and the bio-psycho-social changes. This paper presents the results of the first controlled, experimental pilot study that aimed to analyze the relationship between the perception of back pain and the sleeping position adopted by physically active female seniors. Twenty female seniors (mean age 62.70 ± 3.827) participated in this study. The individuals were separated in 2 groups (Experimental and Control Group). For the carrying out of this study, the Visual Analogue Scale (VAS) was used to measure the intensity of back pain in the spine before and after four consecutive weeks an Intervention program. Individuals in the Experimental Group were instructed regarding the recommended way to sleep position (Intervention program) according to the pathological problems or the amount of pain reported. The Experimental Group (N = 10) presented significantly (p = 0.009) fewer complaints of back pain after an Intervention program in comparison to individuals who did not receive this type of information (Control Group).

  13. Plasma position and current control system enhancements for the JET ITER-like wall

    Energy Technology Data Exchange (ETDEWEB)

    De Tommasi, G. [Associazione EURATOM-ENEA-CREATE, Univ. di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Maviglia, F. [Associazione EURATOM-ENEA-CREATE, Via Claudio 21, 80125 Napoli (Italy); Neto, A.C. [Ass. EURATOM-IST, Instituto de Plasmas e Fusão Nuclear, IST, 1049-001 Lisboa (Portugal); Lomas, P.J.; McCullen, P.; Rimini, F.G. [Euratom-CCFE, Culham Science Centre, OX14 3DB Abingdon (United Kingdom)

    2014-03-15

    Highlights: • JET plasma position and current control system enhanced for the JET ITER like wall. • Vertical stabilization system enhanced to speed up its response and to withstand larger perturbations. • Improved termination management system. • Implementation of the current limit avoidance system. • Implementation of PFX-on-early-task. - Abstract: The upgrade of Joint European Torus (JET) to a new all-metal wall, the so-called ITER-like wall (ILW), has posed a set of new challenges regarding both machine operation and protection. The plasma position and current control (PPCC) system plays a crucial role in minimizing the possibility that the plasma could permanently damage the ILW. The installation of the ILW has driven a number of upgrades of the two PPCC components, namely the Vertical Stabilization (VS) system and the Shape Controller (SC). The VS system has been enhanced in order to speed up its response and to withstand larger perturbations. The SC upgrade includes three new features: an improved termination management system, the current limit avoidance system, and the PFX-on-early-task. This paper describes the PPCC upgrades listed above, focusing on the implementation issues and on the experimental results achieved during the 2011–12 JET experimental campaigns.

  14. Motivational intensity modulates the effects of positive emotions on set shifting after controlling physiological arousal.

    Science.gov (United States)

    Zhou, Ya; Siu, Angela F Y

    2015-12-01

    Recent research on the construct of emotion suggests the integration of a motivational dimension into the traditional two-dimension (subjective valence and physiological arousal) model. The motivational intensity of an emotional state should be taken into account while investigating the emotion-cognition relationship. This study examined how positive emotional states varying in motivational intensity influenced set shifting, after controlling the potential confounding impacts of physiological arousal. In Experiment 1, 155 volunteers performed a set-shifting task after being randomly assigned to five states: high- vs. low-motivating positive affect (interest vs. serenity), high- vs. low-motivating negative affect (disgust vs. anxiety), and neutral state. Eighty-five volunteers participated in Experiment 2, which further examined the effects of higher vs. lower degree of interest. Both experiments measured and compared participants' physiological arousal (blood pressure and pulse rate) under the normal and experimental conditions as the covariate. Results showed no difference in switching performance between the neutral and serenity groups. As compared with the neutral state, the high-motivating positive affect significantly increased set-switching reaction time costs, but reduced error rate costs; the higher the motivational intensity, the greater the time-costs impairment. This indicates a role of the high-motivating positive affect in regulating the balance between the flexible and stable cognitive control. Motivational intensity also modulated the effects of negative emotional states, i.e., disgust caused a larger increase in time costs than anxiety. Further exploration into neurobiological mechanisms that may mediate the emotional effects on set shifting is warranted. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  15. Visual control improves the accuracy of hand positioning in Huntington’s disease

    Directory of Open Access Journals (Sweden)

    Emilia J. Sitek

    2017-08-01

    Full Text Available Background: The study aimed at demonstrating dependence of visual feedback during hand and finger positioning task performance among Huntington’s disease patients in comparison to patients with Parkinson’s disease and cervical dystonia. Material and methods: Eighty-nine patients participated in the study (23 with Huntington’s disease, 25 with Parkinson’s disease with dyskinesias, 21 with Parkinson’s disease without dyskinesias, and 20 with cervical dystonia, scoring ≥20 points on Mini-Mental State Examination in order to assure comprehension of task instructions. Neurological examination comprised of the motor section from the Unified Huntington’s Disease Rating Scale for Huntington’s disease, the Unified Parkinson’s Disease Rating Scale Part II–IV for Parkinson’s disease and the Toronto Western Spasmodic Torticollis Rating Scale for cervical dystonia. In order to compare hand position accuracy under visually controlled and blindfolded conditions, the patient imitated each of the 10 examiner’s hand postures twice, once under the visual control condition and once with no visual feedback provided. Results: Huntington’s disease patients imitated examiner’s hand positions less accurately under blindfolded condition in comparison to Parkinson’s disease without dyskinesias and cervical dystonia participants. Under visually controlled condition there were no significant inter-group differences. Conclusions: Huntington’s disease patients exhibit higher dependence on visual feedback while performing motor tasks than Parkinson’s disease and cervical dystonia patients. Possible improvement of movement precision in Huntington’s disease with the use of visual cues could be potentially useful in the patients’ rehabilitation.

  16. Prone positioning in hypoxemic respiratory failure: meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Kopterides, Petros; Siempos, Ilias I; Armaganidis, Apostolos

    2009-03-01

    Prone positioning is used to improve oxygenation in patients with hypoxemic respiratory failure (HRF). However, its role in clinical practice is not yet clearly defined. The aim of this meta-analysis was to assess the effect of prone positioning on relevant clinical outcomes, such as intensive care unit (ICU) and hospital mortality, days of mechanical ventilation, length of stay, incidence of ventilator-associated pneumonia (VAP) and pneumothorax, and associated complications. We used literature search of MEDLINE, Current Contents, and Cochrane Central Register of Controlled Trials. We focused only on randomized controlled trials reporting clinical outcomes in adult patients with HRF. Four trials met our inclusion criteria, including 662 patients randomized to prone ventilation and 609 patients to supine ventilation. The pooled odds ratio (OR) for the ICU mortality in the intention-to-treat analysis was 0.97 (95% confidence interval [CI], 0.77-1.22), for the comparison between prone and supine ventilated patients. Interestingly, the pooled OR for the ICU mortality in the selected group of the more severely ill patients favored prone positioning (OR, 0.34; 95% CI, 0.18-0.66). The duration of mechanical ventilation and the incidence of pneumothorax were not different between the 2 groups. The incidence of VAP was lower but not statistically significant in patients treated with prone positioning (OR, 0.81; 95% CI, 0.61-1.10). However, prone positioning was associated with a higher risk of pressure sores (OR, 1.49; 95% CI, 1.17-1.89) and a trend for more complications related to the endotracheal tube (OR, 1.30; 95% CI, 0.94-1.80). Despite the inherent limitations of the meta-analytic approach, it seems that prone positioning has no discernible effect on mortality in patients with HRF. It may decrease the incidence of VAP at the expense of more pressure sores and complications related to the endotracheal tube. However, a subgroup of the most severely ill patients may

  17. Positive deviance as a strategy to prevent and control bloodstream infections in intensive care.

    Science.gov (United States)

    Oliveira, Francimar Tinoco de; Ferreira, Maria Manuela Frederico; Araújo, Silvia Teresa Carvalho de; Bessa, Amanda Trindade Teixeira de; Moraes, Advi Catarina Barbachan; Stipp, Marluci Andrade Conceição

    2017-04-03

    To describe the application of positive deviance as a strategy to prevent and control bloodstream infections. An intervention study with nursing and medical team members working in an intensive care unit in a university hospital, between June and December 2014. The four steps of the positive defiance methodology were applied: to define, to determine, to discover and to design. In 90 days, 188 actions were observed, of these, 36.70% (n=69) were related to catheter dressing. In 81.15% (n=56) of these dressings, the professionals most adhered to the use of flexible sterile cotton-tipped swabs to perform antisepsis at catheter entry sites and fixation dressing. Positive deviance contributed to the implementation of proposals to improve work processes and team development related to problems identified in central venous catheter care. Descrever a aplicação do Positive Deviance como estratégia na prevenção e no controle da infecção de corrente sanguínea. Estudo de intervenção realizado na Unidade de Terapia Intensiva de um hospital universitário, com os membros das equipes de enfermagem e médica, de junho a dezembro de 2014. Foram aplicados os quatro passos da metodologia Positive Deviance: Definir, Determinar, Descobrir e Desenhar. Em 90 dias 188 ações foram observadas, destas, 36,70% (n=69) estavam relacionadas aos curativos dos cateteres. Em 81,15% (n=56) desses curativos, o uso da haste flexível estéril para realização da antissepsia do local de inserção do cateter e de sua placa de fixação foi a ação de maior adesão. O Positive Deviance auxiliou na implementação de propostas de melhorias de processo de trabalho e no desenvolvimento da equipe para os problemas identificados no cuidado com o cateter venoso central.

  18. Position Control of Servo Systems Using Feed-Forward Friction Compensation

    International Nuclear Information System (INIS)

    Park, Min Gyu; Kim, Han Me; Shin, Jong Min; Kim, Jong Shik

    2009-01-01

    Friction is an important factor for precise position tracking control of servo systems. Servo systems with highly nonlinear friction are sensitive to the variation of operating condition. To overcome this problem, we use the LuGre friction model which can consider dynamic characteristics of friction. The LuGre friction model is used as a feed-forward compensator to improve tracking performance of servo systems. The parameters of the LuGre friction model are identified through experiments. The experimental result shows that the tracking performance of servo systems with higherly nonlinear friction can be improved by using feed-forward friction compensation

  19. Guaranteed Cost Finite-Time Control of Discrete-Time Positive Impulsive Switched Systems

    Directory of Open Access Journals (Sweden)

    Leipo Liu

    2018-01-01

    Full Text Available This paper considers the guaranteed cost finite-time boundedness of discrete-time positive impulsive switched systems. Firstly, the definition of guaranteed cost finite-time boundedness is introduced. By using the multiple linear copositive Lyapunov function (MLCLF and average dwell time (ADT approach, a state feedback controller is designed and sufficient conditions are obtained to guarantee that the corresponding closed-loop system is guaranteed cost finite-time boundedness (GCFTB. Such conditions can be solved by linear programming. Finally, a numerical example is provided to show the effectiveness of the proposed method.

  20. Minimum Energy Control of 2D Positive Continuous-Discrete Linear Systems

    Directory of Open Access Journals (Sweden)

    Kaczorek Tadeusz

    2014-09-01

    Full Text Available The minimum energy control problem for the 2D positive continuous-discrete linear systems is formulated and solved. Necessary and sufficient conditions for the reachability at the point of the systems are given. Sufficient conditions for the existence of solution to the problem are established. It is shown that if the system is reachable then there exists an optimal input that steers the state from zero boundary conditions to given final state and minimizing the performance index for only one step (q = 1. A procedure for solving of the problem is proposed and illustrated by a numerical example.

  1. ITER-FEAT magnetic configuration and plasma position/shape control in the nominal PF scenario

    International Nuclear Information System (INIS)

    Gribov, Y.V.; Albanese, R.; Ambrosino, G.

    2001-01-01

    The capability of the ITER-FEAT poloidal field system to support the four 'design' scenarios and the high current 'assessed' scenario have been studied. To operate with highly elongated plasma, the system has segmentation of the central solenoid and a separate fast feedback loop for plasma vertical stabilisation. Within the limits imposed on the coil currents, voltages and power, the poloidal field system provides the required plasma scenario and control capabilities. The separatrix deviation from the required position, in scenarios with minor disruptions is within less than about 100 mm. (author)

  2. Technical Note: Mobile accelerator guidance using an optical tracker during docking in IOERT procedures.

    Science.gov (United States)

    Marinetto, Eugenio; Victores, Juan González; García-Sevilla, Mónica; Muñoz, Mercedes; Calvo, Felipe Ángel; Balaguer, Carlos; Desco, Manuel; Pascau, Javier

    2017-10-01

    Intraoperative electron radiation therapy (IOERT) involves the delivery of a high radiation dose during tumor resection in a shorter time than other radiation techniques, thus improving local control of tumors. However, a linear accelerator device is needed to produce the beam safely. Mobile linear accelerators have been designed as dedicated units that can be moved into the operating room and deliver radiation in situ. Correct and safe dose delivery is a key concern when using mobile accelerators. The applicator is commonly fixed to the patient's bed to ensure that the dose is delivered to the prescribed location, and the mobile accelerator is moved to dock the applicator to the radiation beam output (gantry). In a typical clinical set-up, this task is time-consuming because of safety requirements and the limited degree of freedom of the gantry. The objective of this study was to present a navigation solution based on optical tracking for guidance of docking to improve safety and reduce procedure time. We used an optical tracker attached to the mobile linear accelerator to track the prescribed localization of the radiation collimator inside the operating room. Using this information, the integrated navigation system developed computes the movements that the mobile linear accelerator needs to perform to align the applicator and the radiation gantry and warns the physician if docking is unrealizable according to the available degrees of freedom of the mobile linear accelerator. Furthermore, we coded a software application that connects all the necessary functioning elements and provides a user interface for the system calibration and the docking guidance. The system could safeguard against the spatial limitations of the operating room, calculate the optimal arrangement of the accelerator and reduce the docking time in computer simulations and experimental setups. The system could be used to guide docking with any commercial linear accelerator. We believe that the

  3. Seismic vulnerability assessment of an Italian historical masonry dry dock

    OpenAIRE

    Marco Zucca; Pietro Giuseppe Crespi; Nicola Longarini

    2017-01-01

    The paper presents the seismic vulnerability analysis of the military dry dock built in 1861 inside the Messina’s harbor. The study appears very important not only for the relevance of the dry dock itself, but also for its social, military and symbolic role. As a first step, the historical documentation about the dry dock delivered by the Military Technical Office, in charge of its maintenance, was thoroughly examined. This activity was fundamental to understand the construction methods, the ...

  4. Linear Actuator System for the NASA Docking System

    Science.gov (United States)

    Dick, Brandon N.; Oesch, Christopher; Rupp, Timothy W.

    2017-01-01

    The Linear Actuator System (LAS) is a major sub-system within the NASA Docking System (NDS). The NDS Block 1 will be used on the Boeing Crew Space Transportation (CST-100) system to achieve docking with the International Space Station. Critical functions in the Soft Capture aspect of docking are performed by the LAS. This paper describes the general function of the LAS, the system's key requirements and technical challenges, and the development and qualification approach for the system.

  5. Position and Speed Control of Brushless DC Motors Using Sensorless Techniques and Application Trends

    Directory of Open Access Journals (Sweden)

    Jaime Gómez-Gil

    2010-07-01

    Full Text Available This paper provides a technical review of position and speed sensorless methods for controlling Brushless Direct Current (BLDC motor drives, including the background analysis using sensors, limitations and advances. The performance and reliability of BLDC motor drivers have been improved because the conventional control and sensing techniques have been improved through sensorless technology. Then, in this paper sensorless advances are reviewed and recent developments in this area are introduced with their inherent advantages and drawbacks, including the analysis of practical implementation issues and applications. The study includes a deep overview of state-of-the-art back-EMF sensing methods, which includes Terminal Voltage Sensing, Third Harmonic Voltage Integration, Terminal Current Sensing, Back-EMF Integration and PWM strategies. Also, the most relevant techniques based on estimation and models are briefly analysed, such as Sliding-mode Observer, Extended Kalman Filter, Model Reference Adaptive System, Adaptive observers (Full-order and Pseudoreduced-order and Artificial Neural Networks.

  6. Positive identity entry control system with geographically distributed portals and enrollment stations

    International Nuclear Information System (INIS)

    McIntire, J.M.

    1985-01-01

    A positive identity entry control system using distributed processing to allow reliable geographically separated portals and enrollment stations has been installed and is fully operational at a large area DOE site. Identity verification requires a credential, a memorized number and measurement of a physical characteristic of the user. Additionally, all portal activity is monitored by guards. The portal system is dual redundant such that no single point failure will shut down operations. Each portal site maintains its own subset of the master data base so off-site failure of the central data base manager or its communication links will not significantly affect local portal activity. The system is suitable for installations with large populations requiring access control at several remote sites scattered over a large area

  7. Efficient Use of Automatic Exposure Control Systems in Computed Tomography Requires Correct Patient Positioning

    Energy Technology Data Exchange (ETDEWEB)

    Gudjonsdottir, J.; Jonsdottir, B. (Roentgen Domus Medica, Reykjavik (Iceland)); Svensson, J.R.; Campling, S. (Faculty of Health and Social Care, Anglia Ruskin Univ., Cambridge (United Kingdom)); Brennan, P.C. (Diagnostic Imaging, Biological Imaging Research, UCD School of Medicine and Medical Science, Univ. College Dublin, Belfield, Dublin (Ireland))

    2009-11-15

    Background: Image quality and radiation dose to the patient are important factors in computed tomography (CT). To provide constant image quality, tube current modulation (TCM) performed by automatic exposure control (AEC) adjusts the tube current to the patient's size and shape. Purpose: To evaluate the effects of patient centering on tube current-time product (mAs) and image noise. Material and Methods: An oval-shaped acrylic phantom was scanned in various off-center positions, at 30-mm intervals within a 500-mm field of view, using three different CT scanners. Acquisition parameters were similar to routine abdomen examinations at each site. The mAs was recorded and noise measured in the images. The correlation of mAs and noise with position was calculated using Pearson correlation. Results: In all three scanners, the mAs delivered by the AEC changed with y-position of the phantom (P<0.001), with correlation values of 0.98 for scanners A and B and -0.98 for scanner C. With x-position, mAs changes were 4.9% or less. As the phantom moved into the y-positions, compared with the iso-center, the mAs varied by up to +70%, -34%, and +56% in scanners A, B, and C, respectively. For scanners A and B, noise in two regions of interest in the lower part of the phantom decreased with elevation, with correlation factors from -0.95 to -0.86 (P<0.02). In the x-direction, significant noise relationships (P<0.005) were only seen in scanner A. Conclusion: This study demonstrates that patient centering markedly affects the efficacy of AEC function and that tube current changes vary between scanners. Tube position when acquiring the scout projection radiograph is decisive for the direction of the mAs change. Off-center patient positions cause errors in tube current modulation that can outweigh the dose reduction gained by AEC use, and image quality is affected

  8. The reproducibility of organ position using active breathing control (ABC) during liver radiotherapy

    International Nuclear Information System (INIS)

    Dawson, Laura A.; Brock, Kristy K.; Kazanjian, Sahira; Fitch, Dwight; McGinn, Cornelius J.; Lawrence, Theodore S.; Haken, Randall K. ten; Balter, James

    2001-01-01

    Purpose: To evaluate the intrafraction and interfraction reproducibility of liver immobilization using active breathing control (ABC). Methods and Materials: Patients with unresectable intrahepatic tumors who could comfortably hold their breath for at least 20 s were treated with focal liver radiation using ABC for liver immobilization. Fluoroscopy was used to measure any potential motion during ABC breath holds. Preceding each radiotherapy fraction, with the patient setup in the nominal treatment position using ABC, orthogonal radiographs were taken using room-mounted diagnostic X-ray tubes and a digital imager. The radiographs were compared to reference images using a 2D alignment tool. The treatment table was moved to produce acceptable setup, and repeat orthogonal verification images were obtained. The positions of the diaphragm and the liver (assessed by localization of implanted radiopaque intra-arterial microcoils) relative to the skeleton were subsequently analyzed. The intrafraction reproducibility (from repeat radiographs obtained within the time period of one fraction before treatment) and interfraction reproducibility (from comparisons of the first radiograph for each treatment with a reference radiograph) of the diaphragm and the hepatic microcoil positions relative to the skeleton with repeat breath holds using ABC were then measured. Caudal-cranial (CC), anterior-posterior (AP), and medial-lateral (ML) reproducibility of the hepatic microcoils relative to the skeleton were also determined from three-dimensional alignment of repeat CT scans obtained in the treatment position. Results: A total of 262 fractions of radiation were delivered using ABC breath holds in 8 patients. No motion of the diaphragm or hepatic microcoils was observed on fluoroscopy during ABC breath holds. From analyses of 158 sets of positioning radiographs, the average intrafraction CC reproducibility (σ) of the diaphragm and hepatic microcoil position relative to the skeleton

  9. Deep breathing exercises with positive expiratory pressure in patients with multiple sclerosis - a randomized controlled trial.

    Science.gov (United States)

    Westerdahl, Elisabeth; Wittrin, Anna; Kånåhols, Margareta; Gunnarsson, Martin; Nilsagård, Ylva

    2016-11-01

    Breathing exercises with positive expiratory pressure are often recommended to patients with advanced neurological deficits, but the potential benefit in multiple sclerosis (MS) patients with mild and moderate symptoms has not yet been investigated in randomized controlled trials. To study the effects of 2 months of home-based breathing exercises for patients with mild to moderate MS on respiratory muscle strength, lung function, and subjective breathing and health status outcomes. Forty-eight patients with MS according to the revised McDonald criteria were enrolled in a randomized controlled trial. Patients performing breathing exercises (n = 23) were compared with a control group (n = 25) performing no breathing exercises. The breathing exercises were performed with a positive expiratory pressure device (10-15 cmH 2 O) and consisted of 30 slow deep breaths performed twice a day for 2 months. Respiratory muscle strength (maximal inspiratory and expiratory pressure at the mouth), spirometry, oxygenation, thoracic excursion, subjective perceptions of breathing and self-reported health status were evaluated before and after the intervention period. Following the intervention, there was a significant difference between the breathing group and the control group regarding the relative change in lung function, favoring the breathing group (vital capacity: P < 0.043; forced vital capacity: P < 0.025). There were no other significant differences between the groups. Breathing exercises may be beneficial in patients with mild to moderate stages of MS. However, the clinical significance needs to be clarified, and it remains to be seen whether a sustainable effect in delaying the development of respiratory dysfunction in MS can be obtained. © 2015 The Authors. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.

  10. Design and control of a decoupled two degree of freedom translational parallel micro-positioning stage.

    Science.gov (United States)

    Lai, Lei-Jie; Gu, Guo-Ying; Zhu, Li-Min

    2012-04-01

    This paper presents a novel decoupled two degrees of freedom (2-DOF) translational parallel micro-positioning stage. The stage consists of a monolithic compliant mechanism driven by two piezoelectric actuators. The end-effector of the stage is connected to the base by four independent kinematic limbs. Two types of compound flexure module are serially connected to provide 2-DOF for each limb. The compound flexure modules and mirror symmetric distribution of the four limbs significantly reduce the input and output cross couplings and the parasitic motions. Based on the stiffness matrix method, static and dynamic models are constructed and optimal design is performed under certain constraints. The finite element analysis results are then given to validate the design model and a prototype of the XY stage is fabricated for performance tests. Open-loop tests show that maximum static and dynamic cross couplings between the two linear motions are below 0.5% and -45 dB, which are low enough to utilize the single-input-single-out control strategies. Finally, according to the identified dynamic model, an inversion-based feedforward controller in conjunction with a proportional-integral-derivative controller is applied to compensate for the nonlinearities and uncertainties. The experimental results show that good positioning and tracking performances are achieved, which verifies the effectiveness of the proposed mechanism and controller design. The resonant frequencies of the loaded stage at 2 kg and 5 kg are 105 Hz and 68 Hz, respectively. Therefore, the performance of the stage is reasonably good in term of a 200 N load capacity. © 2012 American Institute of Physics

  11. Pathways to Adolescents' Flourishing: Linking Self-Control Skills and Positivity Ratio through Social Support

    Science.gov (United States)

    Orkibi, Hod; Hamama, Liat; Gavriel-Fried, Belle; Ronen, Tammie

    2018-01-01

    This study focused on the ability to experience a high ratio of positive to negative emotions in 807 Israeli adolescents aged 12 to 15 years (50% girls). While considering possible gender differences, we tested a model positing that adolescents' self-control skills would link to their positivity ratio and indirectly through perceived social…

  12. Modelling and Control of Stepper Motors for High Accuracy Positioning Systems Used in Radioactive Environments

    CERN Document Server

    Picatoste Ruilope, Ricardo; Masi, Alessandro

    Hybrid Stepper Motors are widely used in open-loop position applications. They are the choice of actuation for the collimators in the Large Hadron Collider, the largest particle accelerator at CERN. In this case the positioning requirements and the highly radioactive operating environment are unique. The latter forces both the use of long cables to connect the motors to the drives which act as transmission lines and also prevents the use of standard position sensors. However, reliable and precise operation of the collimators is critical for the machine, requiring the prevention of step loss in the motors and maintenance to be foreseen in case of mechanical degradation. In order to make the above possible, an approach is proposed for the application of an Extended Kalman Filter to a sensorless stepper motor drive, when the motor is separated from its drive by long cables. When the long cables and high frequency pulse width modulated control voltage signals are used together, the electrical signals difer greatl...

  13. Sliding-Mode Observer for Speed and Position Sensorless Control of Linear-PMSM

    Directory of Open Access Journals (Sweden)

    Kazraji Saeed Masoumi

    2014-05-01

    Full Text Available The paper presents a sliding-mode observer that utilizes sigmoid function for speed and position sensorless control of permanent-magnet linear synchronous motor (PMLSM. In conventional sliding mode observer method there are the chattering phenomenon and the phase lag. Thus, in order to avoid the usage of the low pass filter and the phase compensator based on back EMF, in this paper a sliding mode observer with sigmoid function for detecting the back EMF in a PMLSM is designed to estimate the speed and the position of the rotor. Most of conventional sliding mode observers use sign or saturation functions which need low pass filter in order to detect back electromotive force (back EMF. In this paper a sigmoid function is used instead of discontinuous sign function to decrease undesirable chattering phenomenon. By reducing the chattering, detecting of the back EMF can be made directly from switching signal without any low pass filter. Thus the delay time in the proposed observer is eliminated because of the low pass filter. Furthermore, there is no need to compensate phase fault in position and speed estimating of linear-PMSM. Advantages of the proposed observer have been shown by simulation with MATLAB software.

  14. Association of Benign Paroxysmal Positional Vertigo with Osteoporosis and Vitamin D Deficiency: A Case Controlled Study.

    Science.gov (United States)

    Karataş, Abdullah; Acar Yüceant, Gülşah; Yüce, Turgut; Hacı, Cemal; Cebi, Işıl Taylan; Salviz, Mehti

    2017-08-01

    Benign paroxysmal positional vertigo (BPPV) is a common type of vertigo caused by the peripheral vestibular system. The majority of cases are accepted as idiopathic. Calcium metabolism also plays a primary role in the synthesis/absorption of otoconia made of calcium carbonate and thus might be an etiological factor in the onset of BPPV. In this study, we aimed to investigate the role of osteoporosis and vitamin D in the etiology of BPPV by comparing BPPV patients with hospital-based controls. This is a case-control study comparing the prevalence of osteoporosis and vitamin D deficiency in 78 BPPV patients and 78 hospital-based controls. The mean T-scores and serum vitamin D levels were compared. The risk factors of osteoporosis, physical activity, diabetes mellitus, body mass index, and blood pressure were all compared between the groups. To avoid selection bias, the groups were stratified as subgroups according to age, sex, and menopausal status. In this study, the rates of osteoporosis and vitamin D deficiency detected in BPPV patients were reasonably high. But there was no significant difference in mean T-scores and vitamin D levels, osteoporosis, and vitamin D deficiency prevalence between the BPPV group and controls. The prevalence of osteoporosis and vitamin D deficiency is reasonably high in the general population. Unlike the general tendencies in the literature, our study suggests that osteoporosis and vitamin D deficiency are not risk factors for BPPV; we conclude that the coexistence of BPPV with osteoporosis and vitamin D deficiency is coincidental.

  15. Validation of Modifications to the ANSR for Listeria Method for Improved Internal Positive Control Performance.

    Science.gov (United States)

    Alles, Susan; Meister, Evan; Hosking, Edan; Tovar, Eric; Shaulis, Rebecca; Schonfeld, Mark; Zhang, Lei; Li, Lin; Biswas, Preetha; Mozola, Mark; Donofrio, Robert; Chen, Yi

    2018-03-01

    A study was conducted to validate a minor reagent formulation change to the ANSR for Listeria method, Performance Tested MethodSM 101202. This change involves increasing the master mix volume prelyophilization by 40% and addition of salmon sperm DNA (nontarget DNA) to the master mix. These changes improve the robustness of the internal positive control response and reduce the possibility of obtaining invalid results due to weak-positive control curves. When three foods (hot dogs, Mexican-style cheese, and cantaloupe) and sponge samples taken from a stainless steel surface were tested, no significant differences in performance between the ANSR and U.S. Food and Drug Administration Bacteriological Analytical Manual or U.S. Department of Agriculture-Food Safety and Inspection Service Microbiology Laboratory Guidebook reference culture procedures were observed for any of the matrixes as determined by probability of detection analysis. Inclusivity and exclusivity testing yielded 100% expected results for target and nontarget bacteria. Accelerated stability testing was carried out over a 7 week period and showed no decrease in assay performance over time.

  16. New Design for the Inductive Position Sensor of the CAREM Reactor Control Bars

    International Nuclear Information System (INIS)

    Esparza, Daniel; D'Ovidio, Claudio; Taglialavore, Eduardo

    2000-01-01

    We describe the new design of the sensor used for determining the position of the control bars in the CAREM reactor.It presently operates under real 'cold' conditions, being under progress the final selection of materials for operation under the 'hot' condition of the reactor.The actual design is a modification of the previous one and is based on the same principle.A solenoid is placed on the outer side of the mechanism that moves the control bar, which has some part made of a magnetic material, and the variation of an electrical property of the bobbin with the movement of this magnetic piece is studied.This new design was proposed both to increase the output voltage and simplify the electronics and construction of the sensor.The output voltage is lineal with the bar position, with a correlation coefficient R = 0.9997, a sensibility of 43 % and a resolution better than 1 in 1000.The output sensibility was improved in almost three orders of magnitude, from 1.204 μV/mm to 0.924 mV/mm. Considering that the typical electric noise was ±1 mV RMS, we are able to measure the mm in the total bar excursion of 1400 mm. It is to be noticed that we obtained a resolution 10 times higher than the required: half step of the mechanism, that is ±10 mm. Both the employed electronics and the bobbin construction were markedly simplified

  17. Effects of systematic prone positioning in hypoxemic acute respiratory failure: a randomized controlled trial.

    Science.gov (United States)

    Guerin, Claude; Gaillard, Sandrine; Lemasson, Stephane; Ayzac, Louis; Girard, Raphaele; Beuret, Pascal; Palmier, Bruno; Le, Quoc Viet; Sirodot, Michel; Rosselli, Sylvaine; Cadiergue, Vincent; Sainty, Jean-Marie; Barbe, Philippe; Combourieu, Emmanuel; Debatty, Daniel; Rouffineau, Jean; Ezingeard, Eric; Millet, Olivier; Guelon, Dominique; Rodriguez, Luc; Martin, Olivier; Renault, Anne; Sibille, Jean-Paul; Kaidomar, Michel

    2004-11-17

    A recent trial showed that placing patients with acute lung injury in the prone position did not increase survival; however, whether those results hold true for patients with hypoxemic acute respiratory failure (ARF) is unclear. To determine whether prone positioning improves mortality in ARF patients. Prospective, unblinded, multicenter controlled trial of 791 ARF patients in 21 general intensive care units in France using concealed randomization conducted from December 14, 1998, through December 31, 2002. To be included, patients had to be at least 18 years, hemodynamically stable, receiving mechanical ventilation, and intubated and had to have a partial pressure of arterial oxygen (PaO2) to fraction of inspired oxygen (FIO2) ratio of 300 or less and no contraindications to lying prone. Patients were randomly assigned to prone position placement (n = 413), applied as early as possible for at least 8 hours per day on standard beds, or to supine position placement (n = 378). The primary end point was 28-day mortality; secondary end points were 90-day mortality, duration of mechanical ventilation, incidence of ventilator-associated pneumonia (VAP), and oxygenation. The 2 groups were comparable at randomization. The 28-day mortality rate was 32.4% for the prone group and 31.5% for the supine group (relative risk [RR], 0.97; 95% confidence interval [CI], 0.79-1.19; P = .77). Ninety-day mortality for the prone group was 43.3% vs 42.2% for the supine group (RR, 0.98; 95% CI, 0.84-1.13; P = .74). The mean (SD) duration of mechanical ventilation was 13.7 (7.8) days for the prone group vs 14.1 (8.6) days for the supine group (P = .93) and the VAP incidence was 1.66 vs 2.14 episodes per 100-patients days of intubation, respectively (P = .045). The PaO2/FIO2 ratio was significantly higher in the prone group during the 28-day follow-up. However, pressure sores, selective intubation, and endotracheal tube obstruction incidences were higher in the prone group. This trial

  18. ADRC for spacecraft attitude and position synchronization in libration point orbits

    Science.gov (United States)

    Gao, Chen; Yuan, Jianping; Zhao, Yakun

    2018-04-01

    This paper addresses the problem of spacecraft attitude and position synchronization in libration point orbits between a leader and a follower. Using dual quaternion, the dimensionless relative coupled dynamical model is derived considering computation efficiency and accuracy. Then a model-independent dimensionless cascade pose-feedback active disturbance rejection controller is designed to spacecraft attitude and position tracking control problems considering parameter uncertainties and external disturbances. Numerical simulations for the final approach phase in spacecraft rendezvous and docking and formation flying are done, and the results show high-precision tracking errors and satisfactory convergent rates under bounded control torque and force which validate the proposed approach.

  19. Effects of tail docking and docking length on neuroanatomical changes in healed tail tips of pigs

    DEFF Research Database (Denmark)

    Herskin, M S; Thodberg, K; Jensen, Henrik Elvang

    2015-01-01

    % (n=19); or leaving 25% (n=11) of the tail length on the pigs. The piglets were docked between day 2 and 4 after birth using a gas-heated apparatus, and were kept under conventional conditions until slaughter at 22 weeks of age, where tails were removed and examined macroscopically and histologically...

  20. Hybrid PD and effective multi-mode positive position feedback control for slewing and vibration suppression of a smart flexible manipulator

    International Nuclear Information System (INIS)

    Lou, Jun-qiang; Wei, Yan-ding; Yang, Yi-ling; Xie, Feng-ran

    2015-01-01

    A hybrid control strategy for slewing and vibration suppression of a smart flexible manipulator is presented in this paper. It consists of a proportional derivative controller to realize motion control, and an effective multi-mode positive position feedback (EMPPF) controller to suppress the multi-mode vibration. Rather than treat each mode equally as the standard multi-mode PPF, the essence of the EMPPF is that control forces of different modes are applied according to the mode parameters of the respective modes, so the vibration modes with less vibration energy receive fewer control forces. Stability conditions for the close loop system are established through stability analysis. Optimal parameters of the EMPPF controller are obtained using the method of root locus analysis. The performance of the proposed strategy is demonstrated by simulation and experiments. Experimental results show that the first two vibration modes of the manipulator are effectively suppressed. The setting time of the setup descends approximately 55%, reaching 3.12 s from 5.67 s. (paper)

  1. Hybrid PD and effective multi-mode positive position feedback control for slewing and vibration suppression of a smart flexible manipulator

    Science.gov (United States)

    Lou, Jun-qiang; Wei, Yan-ding; Yang, Yi-ling; Xie, Feng-ran

    2015-03-01

    A hybrid control strategy for slewing and vibration suppression of a smart flexible manipulator is presented in this paper. It consists of a proportional derivative controller to realize motion control, and an effective multi-mode positive position feedback (EMPPF) controller to suppress the multi-mode vibration. Rather than treat each mode equally as the standard multi-mode PPF, the essence of the EMPPF is that control forces of different modes are applied according to the mode parameters of the respective modes, so the vibration modes with less vibration energy receive fewer control forces. Stability conditions for the close loop system are established through stability analysis. Optimal parameters of the EMPPF controller are obtained using the method of root locus analysis. The performance of the proposed strategy is demonstrated by simulation and experiments. Experimental results show that the first two vibration modes of the manipulator are effectively suppressed. The setting time of the setup descends approximately 55%, reaching 3.12 s from 5.67 s.

  2. A randomised controlled trial in comparing maternal and neonatal outcomes between hands-and-knees delivery position and supine position in China.

    Science.gov (United States)

    Zhang, Hongyu; Huang, Shurong; Guo, Xiaolan; Zhao, Ningning; Lu, Yujing; Chen, Min; Li, Yingxia; Wu, Junqin; Huang, Lihua; Ma, Fenglan; Yang, Yuhong; Zhang, Xiaoli; Zhou, Xiaoyu; Guo, Renfei; Cai, Wenzhi

    2017-07-01

    the supine position is the most frequently offered for birth delivery in China and many other countries, but the hands-and-knees position is now gaining prominence with doctors in China. This study aims to examine the differences in maternal and neonatal outcomes among low-risk women who gave birth either in the hands-and-knees position or the supine position. a randomised controlled trial was conducted in 11 hospitals in China from May to December in 2012. In total, 1400 women were recruited and randomly allocated to either the experimental group (n=700, 446 completed the protocol) who delivered in hands-and-knees position and the control group (n=700, 440 completed the protocol) who delivered in supine position. Women who could not maintain the randomised position during the second stage of labour were allowed to withdraw from the study. The primary maternal outcome measured was rate of episiotomy. Secondary outcomes included degree of perineum laceration, rate of emergency caesarean section, rate of shoulder dystocia, and duration of labour, postpartum bleeding, neonatal Apgar score, and the rate of neonatal asphyxia. Because outcome data were only collected for women who gave birth in the randomised position, per-protocol analyses were used to compare groups. The primary outcome, episiotomy, was also compared between groups using logistic regression adjusting for maternal age,gestational age at birth, whether the woman was primiparous, the process of second stage of labour and birthweight. as compared with the control group, the experimental group had lower rates of episiotomy and second-degree perineum laceration (including episiotomy), and higher rates of intact perineum and first-degree perineum laceration, with a longer duration of second stage of labour. No significant differences were found in the amount of postpartum bleeding, shoulder dystocia, neonatal asphyxia and neonatal Apgar scores at 1minute and 5minutes. Adjusted for maternal age, gestational

  3. Space vehicle with customizable payload and docking station

    Science.gov (United States)

    Judd, Stephen; Dallmann, Nicholas; McCabe, Kevin; Seitz, Daniel

    2018-01-30

    A "black box" space vehicle solution may allow a payload developer to define the mission space and provide mission hardware within a predetermined volume and with predetermined connectivity. Components such as the power module, radios and boards, attitude determination and control system (ADCS), command and data handling (C&DH), etc. may all be provided as part of a "stock" (i.e., core) space vehicle. The payload provided by the payload developer may be plugged into the space vehicle payload section, tested, and launched without custom development of core space vehicle components by the payload developer. A docking station may facilitate convenient development and testing of the space vehicle while reducing handling thereof.

  4. Control of Pan-tilt Mechanism Angle using Position Matrix Method

    Directory of Open Access Journals (Sweden)

    Hendri Maja Saputra

    2013-12-01

    Full Text Available Control of a Pan-Tilt Mechanism (PTM angle for the bomb disposal robot Morolipi-V2 using inertial sensor measurement unit, x-IMU, has been done. The PTM has to be able to be actively controlled both manually and automatically in order to correct the orientation of the moving Morolipi-V2 platform. The x-IMU detects the platform orientation and sends the result in order to automatically control the PTM. The orientation is calculated using the quaternion combined with Madwick and Mahony filter methods. The orientation data that consists of angles of roll (α, pitch (β, and yaw (γ from the x-IMU are then being sent to the camera for controlling the PTM motion (pan & tilt angles after calculating the reverse angle using position matrix method. Experiment results using Madwick and Mahony methods show that the x-IMU can be used to find the robot platform orientation. Acceleration data from accelerometer and flux from magnetometer produce noise with standard deviation of 0.015 g and 0.006 G, respectively. Maximum absolute errors caused by Madgwick and Mahony method with respect to Xaxis are 48.45º and 33.91º, respectively. The x-IMU implementation as inertia sensor to control the Pan-Tilt Mechanism shows a good result, which the probability of pan angle tends to be the same with yaw and tilt angle equal to the pitch angle, except a very small angle shift due to the influence of roll angle..

  5. Multilevel Parallelization of AutoDock 4.2

    Directory of Open Access Journals (Sweden)

    Norgan Andrew P

    2011-04-01

    Full Text Available Abstract Background Virtual (computational screening is an increasingly important tool for drug discovery. AutoDock is a popular open-source application for performing molecular docking, the prediction of ligand-receptor interactions. AutoDock is a serial application, though several previous efforts have parallelized various aspects of the program. In this paper, we report on a multi-level parallelization of AutoDock 4.2 (mpAD4. Results Using MPI and OpenMP, AutoDock 4.2 was parallelized for use on MPI-enabled systems and to multithread the execution of individual docking jobs. In addition, code was implemented to reduce input/output (I/O traffic by reusing grid maps at each node from docking to docking. Performance of mpAD4 was examined on two multiprocessor computers. Conclusions Using MPI with OpenMP multithreading, mpAD4 scales with near linearity on the multiprocessor systems tested. In situations where I/O is limiting, reuse of grid maps reduces both system I/O and overall screening time. Multithreading of AutoDock's Lamarkian Genetic Algorithm with OpenMP increases the speed of execution of individual docking jobs, and when combined with MPI parallelization can significantly reduce the execution time of virtual screens. This work is significant in that mpAD4 speeds the execution of certain molecular docking workloads and allows the user to optimize the degree of system-level (MPI and node-level (OpenMP parallelization to best fit both workloads and computational resources.

  6. Multilevel Parallelization of AutoDock 4.2.

    Science.gov (United States)

    Norgan, Andrew P; Coffman, Paul K; Kocher, Jean-Pierre A; Katzmann, David J; Sosa, Carlos P

    2011-04-28

    Virtual (computational) screening is an increasingly important tool for drug discovery. AutoDock is a popular open-source application for performing molecular docking, the prediction of ligand-receptor interactions. AutoDock is a serial application, though several previous efforts have parallelized various aspects of the program. In this paper, we report on a multi-level parallelization of AutoDock 4.2 (mpAD4). Using MPI and OpenMP, AutoDock 4.2 was parallelized for use on MPI-enabled systems and to multithread the execution of individual docking jobs. In addition, code was implemented to reduce input/output (I/O) traffic by reusing grid maps at each node from docking to docking. Performance of mpAD4 was examined on two multiprocessor computers. Using MPI with OpenMP multithreading, mpAD4 scales with near linearity on the multiprocessor systems tested. In situations where I/O is limiting, reuse of grid maps reduces both system I/O and overall screening time. Multithreading of AutoDock's Lamarkian Genetic Algorithm with OpenMP increases the speed of execution of individual docking jobs, and when combined with MPI parallelization can significantly reduce the execution time of virtual screens. This work is significant in that mpAD4 speeds the execution of certain molecular docking workloads and allows the user to optimize the degree of system-level (MPI) and node-level (OpenMP) parallelization to best fit both workloads and computational resources.

  7. Locally optimal control under unknown dynamics with learnt cost function: application to industrial robot positioning

    Science.gov (United States)

    Guérin, Joris; Gibaru, Olivier; Thiery, Stéphane; Nyiri, Eric

    2017-01-01

    Recent methods of Reinforcement Learning have enabled to solve difficult, high dimensional, robotic tasks under unknown dynamics using iterative Linear Quadratic Gaussian control theory. These algorithms are based on building a local time-varying linear model of the dynamics from data gathered through interaction with the environment. In such tasks, the cost function is often expressed directly in terms of the state and control variables so that it can be locally quadratized to run the algorithm. If the cost is expressed in terms of other variables, a model is required to compute the cost function from the variables manipulated. We propose a method to learn the cost function directly from the data, in the same way as for the dynamics. This way, the cost function can be defined in terms of any measurable quantity and thus can be chosen more appropriately for the task to be carried out. With our method, any sensor information can be used to design the cost function. We demonstrate the efficiency of this method through simulating, with the V-REP software, the learning of a Cartesian positioning task on several industrial robots with different characteristics. The robots are controlled in joint space and no model is provided a priori. Our results are compared with another model free technique, consisting in writing the cost function as a state variable.

  8. Controlled Positioning of Cells in Biomaterials-Approaches Towards 3D Tissue Printing.

    Science.gov (United States)

    Wüst, Silke; Müller, Ralph; Hofmann, Sandra

    2011-08-04

    Current tissue engineering techniques have various drawbacks: they often incorporate uncontrolled and imprecise scaffold geometries, whereas the current conventional cell seeding techniques result mostly in random cell placement rather than uniform cell distribution. For the successful reconstruction of deficient tissue, new material engineering approaches have to be considered to overcome current limitations. An emerging method to produce complex biological products including cells or extracellular matrices in a controlled manner is a process called bioprinting or biofabrication, which effectively uses principles of rapid prototyping combined with cell-loaded biomaterials, typically hydrogels. 3D tissue printing is an approach to manufacture functional tissue layer-by-layer that could be transplanted in vivo after production. This method is especially advantageous for stem cells since a controlled environment can be created to influence cell growth and differentiation. Using printed tissue for biotechnological and pharmacological needs like in vitro drug-testing may lead to a revolution in the pharmaceutical industry since animal models could be partially replaced by biofabricated tissues mimicking human physiology and pathology. This would not only be a major advancement concerning rising ethical issues but would also have a measureable impact on economical aspects in this industry of today, where animal studies are very labor-intensive and therefore costly. In this review, current controlled material and cell positioning techniques are introduced highlighting approaches towards 3D tissue printing.

  9. Controlled Positioning of Cells in Biomaterials—Approaches Towards 3D Tissue Printing

    Directory of Open Access Journals (Sweden)

    Sandra Hofmann

    2011-08-01

    Full Text Available Current tissue engineering techniques have various drawbacks: they often incorporate uncontrolled and imprecise scaffold geometries, whereas the current conventional cell seeding techniques result mostly in random cell placement rather than uniform cell distribution. For the successful reconstruction of deficient tissue, new material engineering approaches have to be considered to overcome current limitations. An emerging method to produce complex biological products including cells or extracellular matrices in a controlled manner is a process called bioprinting or biofabrication, which effectively uses principles of rapid prototyping combined with cell-loaded biomaterials, typically hydrogels. 3D tissue printing is an approach to manufacture functional tissue layer-by-layer that could be transplanted in vivo after production. This method is especially advantageous for stem cells since a controlled environment can be created to influence cell growth and differentiation. Using printed tissue for biotechnological and pharmacological needs like in vitro drug-testing may lead to a revolution in the pharmaceutical industry since animal models could be partially replaced by biofabricated tissues mimicking human physiology and pathology. This would not only be a major advancement concerning rising ethical issues but would also have a measureable impact on economical aspects in this industry of today, where animal studies are very labor-intensive and therefore costly. In this review, current controlled material and cell positioning techniques are introduced highlighting approaches towards 3D tissue printing.

  10. Evaluation of Salivary Vitamin C and Catalase in HIV Positive and Healthy HIV Negative Control Group.

    Science.gov (United States)

    Ahmadi-Motamayel, Fatemeh; Vaziri-Amjad, Samaneh; Goodarzi, Mohammad Taghi; Poorolajal, Jalal

    2017-01-01

    Saliva is a complex oral biologic fluid secreted by major and minor salivary glands. Saliva has immunological, enzymatic and antioxidant defense mechanisms. Infection with human immunodeficiency virus (HIV) is a life-threatening disease. The aim of this study was to evaluate salivary vitamin C and catalase levels in HIV-positive patients in comparison to a healthy control group. Forty-nine HIV-infected individuals and 49 healthy subjects were selected. Five mL of unstimulated saliva was collected in 5 minutes using a sterilized Falcon tube with Navazesh method. Catalase and vitamin C levels were assessed by spectrophotometric assay. Data were analyzed with STATA 12. Salivary catalase levels were 7.99±2.40 and 8.37±1.81 in the case and control groups, respectively. Catalase level was lower in the case group but the difference was not statistically significant (P=0.380). Salivary vitamin C levels in the case and control groups were 3.76±1.92 and 4.87±2.20, respectively (P=0.009). HIV can alter salivary antioxidant capacity as well as vitamin C and catalase levels. Saliva may reflect serum antioxidative changes in these patients. Therefore, further research is necessary on salivary and serum oxidants and the antioxidant changes. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  11. Control of positive end-expiratory pressure (PEEP for small animal ventilators

    Directory of Open Access Journals (Sweden)

    Leão Nunes Marcelo V

    2010-07-01

    Full Text Available Abstract Background The positive end-expiratory pressure (PEEP for the mechanical ventilation of small animals is frequently obtained with water seals or by using ventilators developed for human use. An alternative mechanism is the use of an on-off expiratory valve closing at the moment when the alveolar pressure is equal to the target PEEP. In this paper, a novel PEEP controller (PEEP-new and the PEEP system of a commercial small-animal ventilator, both based on switching an on-off valve, are evaluated. Methods The proposed PEEP controller is a discrete integrator monitoring the error between the target PEEP and the airways opening pressure prior to the onset of an inspiratory cycle. In vitro as well as in vivo experiments with rats were carried out and the PEEP accuracy, settling time and under/overshoot were considered as a measure of performance. Results The commercial PEEP controller did not pass the tests since it ignores the airways resistive pressure drop, resulting in a PEEP 5 cmH2O greater than the target in most conditions. The PEEP-new presented steady-state errors smaller than 0.5 cmH2O, with settling times below 10 s and under/overshoot smaller than 2 cmH2O. Conclusion The PEEP-new presented acceptable performance, considering accuracy and temporal response. This novel PEEP generator may prove useful in many applications for small animal ventilators.

  12. [Wuling Capsule for climacteric patients with depression and anxiety state: a randomized, positive parallel controlled trial].

    Science.gov (United States)

    Wang, Xing-juan; Li, Ji; Zou, Qin-di; Jin, Ling

    2009-11-01

    The incidence of menopausal anxiety and depression is increasing. It can induce and aggravate a variety of somatic symptoms. Despite of the good effects of psychotropic drugs on the disease, patients' compliance is poor. Therefore, it is necessary to find a drug which is practical, effective, and easy for patients to take. To evaluate the efficacy of Wuling Capsule (WC), a Chinese herbal medicine, in treatment of female climacteric syndrome with depression and anxiety state. A total of 96 outpatients of female climacteric syndrome from Department of Gynecology of Integrated Traditional Chinese and Western Medicine, Huashan Hospital, Fudan University, Department of Gynecology of Traditional Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, and Department of Traditional Chinese Medicine, Obstetrics and Gynecology Hospital, Fudan University were included. The study was designed as a randomized, positive drug parallel controlled trial. The patients were divided into WC group (64 cases) and control group (32 cases) and were orally administered Wuling Capsule and Gengnianan Tablet, respectively. The efficacy was evaluated with Kupperman menopausal index (KMI), Self-rating Depression Scale (SDS), and Self-rating Anxiety Scale (SAS) before treatment, and after 3-week and 6-week treatment. The total response rate was 89.66% (52/58) in the WC group, which was superior to that in the control group [76.67% (23/30)]. Ridit test showed that there was a significant difference between the two groups (Pstate. Wuling Capsule is more effective to alleviate depression and anxiety as compared with Gengnianan Tablet.

  13. An Experimental Investigation of Leak Rate Performance of a Subscale Candidate Elastomer Docking Space Seal

    Science.gov (United States)

    Garafolo, Nicholas G.; Daniels, Christopher C.

    2011-01-01

    A novel docking seal was developed for the main interface seal of NASA s Low Impact Docking System (LIDS). This interface seal was designed to maintain acceptable leak rates while being exposed to the harsh environmental conditions of outer space. In this experimental evaluation, a candidate docking seal assembly called Engineering Development Unit (EDU58) was characterized and evaluated against the Constellation Project leak rate requirement. The EDU58 candidate seal assembly was manufactured from silicone elastomer S0383-70 vacuum molded in a metal retainer ring. Four seal designs were considered with unique characteristic heights. The leak rate performance was characterized through a mass point leak rate method by monitoring gas properties within an internal control volume. The leakage performance of the seals were described herein at representative docking temperatures of -50, +23, and +50 C for all four seal designs. Leak performance was also characterized at 100, 74, and 48 percent of full closure. For all conditions considered, the candidate seal assemblies met the Constellation Project leak rate requirement.

  14. Solving a molecular docking problem by the modified PSO method

    Directory of Open Access Journals (Sweden)

    A. P. Karpenko

    2014-01-01

    Full Text Available The paper presents an canonical method of the swarm particles in two modifications to raise this method efficiency in solving multi-extreme problems of high dimension optimization. The essence of PSO-M1 modification is to form two new points to attract swarm particles (along with the points which are responsible for inertial, cognitive, and social components of canonical method. These new points represent the best points of sets of particles-neighbours of a given point. The modification aims to diversify search. All free parameters of the PSO-M1 method (as well as an canonical method are static. In contrast, one of such parameters of PSO-M2 modification is dynamic. So this modification represents an example of a self-adaptive method of optimization. The modification aims to intensify search. A computing experiment to study the method efficiency and its abovementioned modifications at solving the test problems of optimization showed advantages of offered modifications in comparison with canonical method, revealed a superiority of PSO-M2 modification both over canonical method, and over PSO-M1 modification. Using the PSO-M2 method allows us to solve the 28-dimensional molecular docking problem of HIV1 protease and darunaviry 3U7S as the molecules of receptor and a ligand, respectively. Results of computing experiment have shown that the PSO-M2 method successfully finds the position of ligand close to native and can be recommended for solving the molecular docking problems as an alternative to genetic algorithm.

  15. How well do the substrates KISS the enzyme? Molecular docking program selection for feruloyl esterases

    DEFF Research Database (Denmark)

    Udatha, D. B. R. K. Gupta; Sugaya, Nobuyoshi; Olsson, Lisbeth

    2012-01-01

    Molecular docking is the most commonly used technique in the modern drug discovery process where computational approaches involving docking algorithms are used to dock small molecules into macromolecular target structures. Over the recent years several evaluation studies have been reported...

  16. Assessment of Spatial Navigation and Docking Performance During Simulated Rover Tasks

    Science.gov (United States)

    Wood, S. J.; Dean, S. L.; De Dios, Y. E.; Moore, S. T.

    2010-01-01

    INTRODUCTION: Following long-duration exploration transits, pressurized rovers will enhance surface mobility to explore multiple sites across Mars and other planetary bodies. Multiple rovers with docking capabilities are envisioned to expand the range of exploration. However, adaptive changes in sensorimotor and cognitive function may impair the crew s ability to safely navigate and perform docking tasks shortly after transition to the new gravitoinertial environment. The primary goal of this investigation is to quantify post-flight decrements in spatial navigation and docking performance during a rover simulation. METHODS: Eight crewmembers returning from the International Space Station will be tested on a motion simulator during four pre-flight and three post-flight sessions over the first 8 days following landing. The rover simulation consists of a serial presentation of discrete tasks to be completed within a scheduled 10 min block. The tasks are based on navigating around a Martian outpost spread over a 970 sq m terrain. Each task is subdivided into three components to be performed as quickly and accurately as possible: (1) Perspective taking: Subjects use a joystick to indicate direction of target after presentation of a map detailing current orientation and location of the rover with the task to be performed. (2) Navigation: Subjects drive the rover to the desired location while avoiding obstacles. (3) Docking: Fine positioning of the rover is required to dock with another object or align a camera view. Overall operator proficiency will be based on how many tasks the crewmember can complete during the 10 min time block. EXPECTED RESULTS: Functionally relevant testing early post-flight will develop evidence regarding the limitations to early surface operations and what countermeasures are needed. This approach can be easily adapted to a wide variety of simulated vehicle designs to provide sensorimotor assessments for other operational and civilian populations.

  17. DECK: Distance and environment-dependent, coarse-grained, knowledge-based potentials for protein-protein docking

    Directory of Open Access Journals (Sweden)

    Vakser Ilya A

    2011-07-01

    Full Text Available Abstract Background Computational approaches to protein-protein docking typically include scoring aimed at improving the rank of the near-native structure relative to the false-positive matches. Knowledge-based potentials improve modeling of protein complexes by taking advantage of the rapidly increasing amount of experimentally derived information on protein-protein association. An essential element of knowledge-based potentials is defining the reference state for an optimal description of the residue-residue (or atom-atom pairs in the non-interaction state. Results The study presents a new Distance- and Environment-dependent, Coarse-grained, Knowledge-based (DECK potential for scoring of protein-protein docking predictions. Training sets of protein-protein matches were generated based on bound and unbound forms of proteins taken from the DOCKGROUND resource. Each residue was represented by a pseudo-atom in the geometric center of the side chain. To capture the long-range and the multi-body interactions, residues in different secondary structure elements at protein-protein interfaces were considered as different residue types. Five reference states for the potentials were defined and tested. The optimal reference state was selected and the cutoff effect on the distance-dependent potentials investigated. The potentials were validated on the docking decoys sets, showing better performance than the existing potentials used in scoring of protein-protein docking results. Conclusions A novel residue-based statistical potential for protein-protein docking was developed and validated on docking decoy sets. The results show that the scoring function DECK can successfully identify near-native protein-protein matches and thus is useful in protein docking. In addition to the practical application of the potentials, the study provides insights into the relative utility of the reference states, the scope of the distance dependence, and the coarse-graining of

  18. Analysis of magnetic field and hysteresis of reed switches for control rod position indicator of SMART CEDM

    International Nuclear Information System (INIS)

    Yoo, J. W.; Kim, J. H.; Heo, H.; Kim, J. I.; Jang, M. H.

    2002-01-01

    The reliability and accuracy of the information on control rod position are very important to the reactor safety and the design of the core protection system. A survey on the RSPT(Reed Switch Position Transmitter) type control rod position indication system and its actual implementation in the exiting nuclear power plants in Korea was performed first. The control rod position indicator having the high performance for SMART was developed on the basis of RSPT technology identified through the survey. The hysteresis of reed switches is one of the important factors in a repeat accuracy of control rod position indication. In this study, the hysteresis of reed switches is introduced and the design method using the magnetic analysis of reed switches in presented

  19. Improved accuracy of cell surface shaving proteomics in Staphylococcus aureus using a false-positive control

    DEFF Research Database (Denmark)

    Solis, Nestor; Larsen, Martin Røssel; Cordwell, Stuart J

    2010-01-01

    Proteolytic treatment of intact bacterial cells is an ideal means for identifying surface-exposed peptide epitopes and has potential for the discovery of novel vaccine targets. Cell stability during such treatment, however, may become compromised and result in the release of intracellular proteins...... that complicate the final analysis. Staphylococcus aureus is a major human pathogen, causing community and hospital-acquired infections, and is a serious healthcare concern due to the increasing prevalence of multiple antibiotic resistances amongst clinical isolates. We employed a cell surface "shaving" technique...... to trypsin and three identified in the control. The use of a subtracted false-positive strategy improved enrichment of surface-exposed peptides in the trypsin data set to approximately 80% (124/155 peptides). Predominant surface proteins were those associated with methicillin resistance-surface protein SACOL...

  20. Significance of the Resonance Condition for Controlling the Seam Position in Laser-assisted TIG Welding

    Science.gov (United States)

    Emde, B.; Huse, M.; Hermsdorf, J.; Kaierle, S.; Wesling, V.; Overmeyer, L.; Kozakov, R.; Uhrlandt, D.

    As an energy-preserving variant of laser hybrid welding, laser-assisted arc welding uses laser powers of less than 1 kW. Recent studies have shown that the electrical conductivity of a TIG welding arc changes within the arc in case of a resonant interaction between laser radiation and argon atoms. This paper presents investigations on how to control the position of the arc root on the workpiece by means of the resonant interaction. Furthermore, the influence on the welding result is demonstrated. The welding tests were carried out on a cooled copper plate and steel samples with resonant and non-resonant laser radiation. Moreover, an analysis of the weld seam is presented.

  1. On-line system for control of plasma filament position in the Tokamak-10

    International Nuclear Information System (INIS)

    Britousov, N.N.; Valuev, S.F.; Sychev, G.I.; Shchedrov, V.M.

    1982-01-01

    The plasma filament position on-line control system (OCS) in the T-10 tokamak is described. Results of adjustment and operation of the system are given. The OCS is a structure of a direct negative feedback (DNF) versus deflection and a local DNF circuit. The OCS experimental studying is carried out under the following conditions: 200 kA plasma current, 32 cm diaphragm radius, 2.2-2.5 stability margin, 440 V anode voltage. The response time for 2 cm deflection jumps is 15-20 ns. The OCS demonstrated a particular efficiency while operating in parallel with the plasma current stabilizer providing a high discharge repetition and considerably reducing the number of substandard pulses

  2. Disarmament and control of nuclear weapons: Russian positions and their national and international determining factors

    International Nuclear Information System (INIS)

    Facon, Isabelle

    2009-01-01

    In a context where Russia seems to come back to some key principles which guided its international action since the end of Cold War, and relationships between Russia and the USA have been degraded since the US intervention in Iraq (2003), the author examines whether these new Russian postures also concern strategic disarmament, whether Russia is loosing its interest in traditional arrangements of strategic stability, and what are Moscow's priorities within the perspective of expiry of the START 1 Treaty. Thus, the author discusses the role of nuclear weapons in the Russian defence policy, outlines the paradoxes of Russian negotiation positions in the fields of disarmament and arms control, and highlights indirect approaches adopted by Russia on these issues

  3. Automatic laser beam position control on the Isolde-Rilis experiment

    CERN Document Server

    Grancharova, D; Fedosseev, V; Suberlucq, Guy; CERN. Geneva. AB Department

    2003-01-01

    The On-Line Isotope Mass Separator ISOLDE at CERN is a facility for production of radioactive ion beams by the interaction of proton beams with a thick target. One of the most widely used types of ion source at ISOLDE is a chemically selective laser ion source based on the method of laser ionization of atoms in a hot cavity - RILIS (Resonance Ionization Laser Ion Source). The optical set-up of RILIS includes three copper vapour lasers, a set of dye lasers and frequency multiplication crystals giving up to three different beams of tuneable wavelengths. This paper will focus on the transport of the laser beams to the targets at distances of 18 m and 23 m, the development of the acquisition of their position and finally the automatic control of optics for an accurate alignment.

  4. Implementation of the Control and supervision of ALICE ZDC positioning Systems- TWEEP-08

    CERN Document Server

    Swoboda, Detlef

    2008-01-01

    The ALICE Zero Degree Calorimeters (ZDC) have been installed to either side of the LHC IP2 in the machine tunnel next to the dipole magnet D2. The calorimeter modules are mounted on a special table equipped with a mechanism to lower the modules away from the beam orbit during injection and acceleration. During stable operation the modules can be raised individually to be aligned with the beam orbit. The horizontal clearance between ZDC modules and beam pipe will be only about 3 mm. Anti-collision switches are therefore installed to protect the beam pipes against accidental damage. The movement of the calorimeter modules and the protection switches are remote controlled by the ALICE ZDC positioning system.

  5. Benign Paroxysmal Positional Vertigo after Dental Procedures: A Population-Based Case-Control Study.

    Directory of Open Access Journals (Sweden)

    Tzu-Pu Chang

    Full Text Available Benign paroxysmal positional vertigo (BPPV, the most common type of vertigo in the general population, is thought to be caused by dislodgement of otoliths from otolithic organs into the semicircular canals. In most cases, however, the cause behind the otolith dislodgement is unknown. Dental procedures, one of the most common medical treatments, are considered to be a possible cause of BPPV, although this has yet to be proven. This study is the first nationwide population-based case-control study conducted to investigate the correlation between BPPV and dental manipulation.Patients diagnosed with BPPV between January 1, 2007 and December 31, 2012 were recruited from the National Health Insurance Research Database in Taiwan. We further identified those who had undergone dental procedures within 1 month and within 3 months before the first diagnosis date of BPPV. We also identified the comorbidities of the patients with BPPV, including head trauma, osteoporosis, migraine, hypertension, diabetes, hyperlipidemia and stroke. These variables were then compared to those in age- and gender-matched controls.In total, 768 patients with BPPV and 1536 age- and gender-matched controls were recruited. In the BPPV group, 9.2% of the patients had undergone dental procedures within 1 month before the diagnosis of BPPV. In contrast, only 5.5% of the controls had undergone dental treatment within 1 month before the date at which they were identified (P = 0.001. After adjustments for demographic factors and comorbidities, recent exposure to dental procedures was positively associated with BPPV (adjusted odds ratio 1.77; 95% confidence interval 1.27-2.47. This association was still significant if we expanded the time period from 1 month to 3 months (adjusted odds ratio 1.77; 95% confidence interval 1.39-2.26.Our results demonstrated a correlation between dental procedures and BPPV. The specialists who treat patients with BPPV should consider dental procedures to be a

  6. Benign Paroxysmal Positional Vertigo after Dental Procedures: A Population-Based Case-Control Study.

    Science.gov (United States)

    Chang, Tzu-Pu; Lin, Yueh-Wen; Sung, Pi-Yu; Chuang, Hsun-Yang; Chung, Hsien-Yang; Liao, Wen-Ling

    2016-01-01

    Benign paroxysmal positional vertigo (BPPV), the most common type of vertigo in the general population, is thought to be caused by dislodgement of otoliths from otolithic organs into the semicircular canals. In most cases, however, the cause behind the otolith dislodgement is unknown. Dental procedures, one of the most common medical treatments, are considered to be a possible cause of BPPV, although this has yet to be proven. This study is the first nationwide population-based case-control study conducted to investigate the correlation between BPPV and dental manipulation. Patients diagnosed with BPPV between January 1, 2007 and December 31, 2012 were recruited from the National Health Insurance Research Database in Taiwan. We further identified those who had undergone dental procedures within 1 month and within 3 months before the first diagnosis date of BPPV. We also identified the comorbidities of the patients with BPPV, including head trauma, osteoporosis, migraine, hypertension, diabetes, hyperlipidemia and stroke. These variables were then compared to those in age- and gender-matched controls. In total, 768 patients with BPPV and 1536 age- and gender-matched controls were recruited. In the BPPV group, 9.2% of the patients had undergone dental procedures within 1 month before the diagnosis of BPPV. In contrast, only 5.5% of the controls had undergone dental treatment within 1 month before the date at which they were identified (P = 0.001). After adjustments for demographic factors and comorbidities, recent exposure to dental procedures was positively associated with BPPV (adjusted odds ratio 1.77; 95% confidence interval 1.27-2.47). This association was still significant if we expanded the time period from 1 month to 3 months (adjusted odds ratio 1.77; 95% confidence interval 1.39-2.26). Our results demonstrated a correlation between dental procedures and BPPV. The specialists who treat patients with BPPV should consider dental procedures to be a risk factor

  7. Radiation Therapy for Control of Soft-Tissue Sarcomas Resected With Positive Margins

    International Nuclear Information System (INIS)

    DeLaney, Thomas F.; Kepka, Lucyna; Goldberg, Saveli I.; Hornicek, Francis J.; Gebhardt, Mark C.; Yoon, Sam S.; Springfield, Dempsey S.; Raskin, Kevin A.; Harmon, David C.; Kirsch, David G.; Mankin, Henry J.; Rosenberg, Andrew E.; Nielsen, G. Petur; Suit, Herman D.

    2007-01-01

    Purpose: Positive margins (PM) remain after surgery in some soft-tissue sarcoma (STS) patients. We investigated the efficacy of radiation therapy (RT) in STS patients with PM. Methods and Materials: A retrospective chart review was performed on 154 patients with STS at various anatomic sites with PM, defined as tumor on ink, who underwent RT with curative intent between 1970 and 2001. Local control (LC), disease-free survival (DFS), and overall survival (OS) rates were evaluated by univariate (log-rank) and multivariate analysis of prognostic and treatment factors. Results: At 5 years, actuarial LC, DFS, and OS rates were: 76%, 46.7%, and 65.2%, respectively. LC was highest with extremity lesions (p 64 Gy (p 64 Gy had higher 5-year LC, DFS, and OS rates of 85%, 52.1%, and 67.8% vs. 66.1%, 41.8%, and 62.9% if ≤64 Gy, p 50), also significantly influenced OS. By multivariate analysis, the best predictors of LC were site (extremity vs. other), p 64 vs. ≤64 Gy), p 64 Gy, superficial location, and extremity site are associated with improved LC. OS is worse in patients with tumors with lesions >5 cm, grossly positive margins, and after local failure

  8. Igf2/H19 Imprinting Control Region (ICR: An Insulator or a Position-Dependent Silencer?

    Directory of Open Access Journals (Sweden)

    Subhasis Banerjee

    2001-01-01

    Full Text Available The imprinting control region (ICR located far upstream of the H19 gene, in conjunction with enhancers, modulates the transcription of Igf2 and H19 genes in an allele-specific manner. On paternal inheritance, the methylated ICR silences the H19 gene and indirectly facilitates transcription from the distant Igf2 promoter, whereas on the maternal chromosome the unmethylated ICR, together with enhancers, activates transcription of the H19 gene and thereby contributes to the repression of Igf2. This repression of maternal Igf2 has recently been postulated to be due to a chromatin boundary or insulator function of the unmethylated ICR. Central to the insulator model is the site-specific binding of a ubiquitous nuclear factor CTCF which exhibits remarkable flexibility in functioning as transcriptional activator or silencer. We suggest that the ICR positioned close to the enhancers in an episomal context might function as a transcriptional silencer by virtue of interaction of CTCF with its modifiers such as SIN3A and histone deacetylases. Furthermore, a localised folded chromatin structure resulting from juxtaposition of two disparate regulatory sequences (enhancer ICR could be the mechanistic basis of ICR-mediated position-dependent (ICR-promoter transcriptional repression in transgenic Drosophila.

  9. En route position and time control of aircraft using Kalman filtering of radio aid data

    Science.gov (United States)

    Mcgee, L. A.; Christensen, J. V.

    1973-01-01

    Fixed-time-of-arrival (FTA) guidance and navigation is investigated as a possible technique capable of operation within much more stringent en route separation standards and offering significant advantages in safety, higher traffic densities, and improved scheduling reliability, both en route and in the terminal areas. This study investigated the application of FTA guidance previously used in spacecraft guidance. These FTA guidance techniques have been modified and are employed to compute the velocity corrections necessary to return an aircraft to a specified great-circle reference path in order to exercise en route time and position control throughout the entire flight. The necessary position and velocity estimates to accomplish this task are provided by Kalman filtering of data from Loran-C, VORTAC/TACAN, Doppler radar, radio or barometric altitude,and altitude rate. The guidance and navigation system was evaluated using a digital simulation of the cruise phase of supersonic and subsonic flights between San Francisco and New York City, and between New York City and London.

  10. Position control of desiccation cracks by memory effect and Faraday waves.

    Science.gov (United States)

    Nakayama, Hiroshi; Matsuo, Yousuke; Takeshi, Ooshida; Nakahara, Akio

    2013-01-01

    Pattern formation of desiccation cracks on a layer of a calcium carbonate paste is studied experimentally. This paste is known to exhibit a memory effect, which means that a short-time application of horizontal vibration to the fresh paste predetermines the direction of the cracks that are formed after the paste is dried. While the position of the cracks (as opposed to their direction) is still stochastic in the case of horizontal vibration, the present work reports that their positioning is also controllable, at least to some extent, by applying vertical vibration to the paste and imprinting the pattern of Faraday waves, thus breaking the translational symmetry of the system. The experiments show that the cracks tend to appear in the node zones of the Faraday waves: in the case of stripe-patterned Faraday waves, the cracks are formed twice more frequently in the node zones than in the anti-node zones, presumably due to the localized horizontal motion. As a result of this preference of the cracks to the node zones, the memory of the square lattice pattern of Faraday waves makes the cracks run in the oblique direction differing by 45 degrees from the intuitive lattice direction of the Faraday waves.

  11. Empirical methods for controlling false positives and estimating confidence in ChIP-Seq peaks

    Directory of Open Access Journals (Sweden)

    Courdy Samir J

    2008-12-01

    Full Text Available Abstract Background High throughput signature sequencing holds many promises, one of which is the ready identification of in vivo transcription factor binding sites, histone modifications, changes in chromatin structure and patterns of DNA methylation across entire genomes. In these experiments, chromatin immunoprecipitation is used to enrich for particular DNA sequences of interest and signature sequencing is used to map the regions to the genome (ChIP-Seq. Elucidation of these sites of DNA-protein binding/modification are proving instrumental in reconstructing networks of gene regulation and chromatin remodelling that direct development, response to cellular perturbation, and neoplastic transformation. Results Here we present a package of algorithms and software that makes use of control input data to reduce false positives and estimate confidence in ChIP-Seq peaks. Several different methods were compared using two simulated spike-in datasets. Use of control input data and a normalized difference score were found to more than double the recovery of ChIP-Seq peaks at a 5% false discovery rate (FDR. Moreover, both a binomial p-value/q-value and an empirical FDR were found to predict the true FDR within 2–3 fold and are more reliable estimators of confidence than a global Poisson p-value. These methods were then used to reanalyze Johnson et al.'s neuron-restrictive silencer factor (NRSF ChIP-Seq data without relying on extensive qPCR validated NRSF sites and the presence of NRSF binding motifs for setting thresholds. Conclusion The methods developed and tested here show considerable promise for reducing false positives and estimating confidence in ChIP-Seq data without any prior knowledge of the chIP target. They are part of a larger open source package freely available from http://useq.sourceforge.net/.

  12. Cognitive reappraisal and secondary control coping: associations with working memory, positive and negative affect, and symptoms of anxiety/depression.

    Science.gov (United States)

    Andreotti, Charissa; Thigpen, Jennifer E; Dunn, Madeleine J; Watson, Kelly; Potts, Jennifer; Reising, Michelle M; Robinson, Kristen E; Rodriguez, Erin M; Roubinov, Danielle; Luecken, Linda; Compas, Bruce E

    2013-01-01

    The current study examined the relations of measures of cognitive reappraisal and secondary control coping with working memory abilities, positive and negative affect, and symptoms of anxiety and depression in young adults (N=124). Results indicate significant relations between working memory abilities and reports of secondary control coping and between reports of secondary control coping and cognitive reappraisal. Associations were also found between measures of secondary control coping and cognitive reappraisal and positive and negative affect and symptoms of depression and anxiety. Further, the findings suggest that reports of cognitive reappraisal may be more strongly predictive of positive affect whereas secondary control coping may be more strongly predictive of negative affect and symptoms of depression and anxiety. Overall, the results suggest that current measures of secondary control coping and cognitive reappraisal capture related but distinct constructs and suggest that the assessment of working memory may be more strongly related to secondary control coping in predicting individual differences in distress.

  13. Molecular Dynamics and Docking of Biphenyl: A Potential ...

    African Journals Online (AJOL)

    Results: Molecular docking by FireDock web server showed that biPhe-43 and Trp-43-mutated CD4 inhibited the binding of ... In a 5ns MD simulation, biPhe-43 and Trp-43 mutated CD4 .... 'unbound' MD on UMHPC Linux Cluster SGIAltix.

  14. Bioengineering of Tobacco Mosaic Virus to Create a Non-Infectious Positive Control for Ebola Diagnostic Assays

    Science.gov (United States)

    Lam, Patricia; Gulati, Neetu M.; Stewart, Phoebe L.; Keri, Ruth A.; Steinmetz, Nicole F.

    2016-03-01

    The 2014 Ebola epidemic is the largest to date. There is no cure or treatment for this deadly disease; therefore there is an urgent need to develop new diagnostics to accurately detect Ebola. Current RT-PCR assays lack sensitive and reliable positive controls. To address this critical need, we devised a bio-inspired positive control for use in RT-PCR diagnostics: we encapsulated scrambled Ebola RNA sequences inside of tobacco mosaic virus to create a biomimicry that is non-infectious, but stable, and could therefore serve as a positive control in Ebola diagnostic assays. Here, we report the bioengineering and validation of this probe.

  15. A novel position-sensorless control method for brushless DC motors

    International Nuclear Information System (INIS)

    Zhang, X.Z.; Wang, Y.N.

    2011-01-01

    This paper presents the design and implementation of a high performance position-sensorless control scheme for the extensively used brushless DC (BLDC) motors. In the proposed method, with proper PWM strategy, instead of detecting the zero-crossing point (ZCP) of the nonexcited motor back electromagnetic force (EMF) or the average motor terminal to neutral voltage, the true zero-crossing points of back EMF are extracted directly from the difference of the specific average line-to-line voltages with simple RC circuits and comparators. In contrast to conventional methods, the neutral voltage is not needed and the diode freewheeling currents in the nonconducted phase are eliminated completely; therefore, the commutation signals are more accurate and insensitive to the common-mode noise. Moreover, 100% pulse-width-modulation (PWM) duty ratio control of BLDC motors is provided with the presented method. As a result, the proposed method makes it possible to achieve good motor performance over a wide speed range and to simplify the starting procedure. The detailed circuit model is analyzed and some experimental results obtained from a sensorless prototype are shown to verify the analysis and confirm the validity of the proposed method.

  16. M.V.A. amplifier for plasma position control by vertical magnetic field

    International Nuclear Information System (INIS)

    Schenk, G.

    1978-01-01

    The radial plasma position in the WEGA torus is controlled by a power amplifier, acting on the vertical magnetic field. Up to now the feedback loop contains, as amplifying elements, two 90 kW DC-transistor amplifiers, acting in push-pull operation. As increased plasma stability and lifetime is desirable, we have to increase the power amplifier to about 1 Megawatt. Industry offered a thyristor rectifier, operating at 50 or 300 Hz, and alternatively a thyristor chopper amplifier at a few kHz frequency response. Theses offers did not correspond to our demand, as far as response time, price and primary power requirements are concerned. We have implemented a bipolar switching-type amplifier (also called H-bridge converter) with the characteristics: time response < 0,05 ms., pulsed power = 1 MW (400 V, 2500 A), primary power = 2,5 kW. As power switch, a network of parallel high voltage transistors, driven by three transistor stages, has been chosen, to control a vertical magnetic field or +/- 180 G, with a precision of about one per cent. Precautions for transistor switches concerning mainly critical voltage, current, instantaneous power and selfoscillating behaviour have been taken. This systems corresponds to our demands

  17. Effect of Continuous Positive Airway Pressure on Stroke Rehabilitation: A Pilot Randomized Sham-Controlled Trial

    Science.gov (United States)

    Khot, Sandeep P.; Davis, Arielle P.; Crane, Deborah A.; Tanzi, Patricia M.; Li Lue, Denise; Claflin, Edward S.; Becker, Kyra J.; Longstreth, W.T.; Watson, Nathaniel F.; Billings, Martha E.

    2016-01-01

    Study Objectives: Obstructive sleep apnea (OSA) predicts poor functional outcome after stroke and increases the risk for recurrent stroke. Less is known about continuous positive airway pressure (CPAP) treatment on stroke recovery. Methods: In a pilot randomized, double-blind, sham-controlled trial, adult stroke rehabilitation patients were assigned to auto-titrating or sham CPAP without diagnostic testing for OSA. Change in Functional Independence Measure (FIM), a measure of disability, was assessed between rehabilitation admission and discharge. Results: Over 18 months, 40 patients were enrolled and 10 withdrew from the study: 7 from active and 3 from sham CPAP (p > 0.10). For the remaining 30 patients, median duration of CPAP use was 14 days. Average CPAP use was 3.7 h/night, with at least 4 h nightly use among 15 patients. Adherence was not influenced by treatment assignment or stroke severity. In intention-to-treat analyses (n = 40), the median change in FIM favored active CPAP over sham but did not reach statistical significance (34 versus 26, p = 0.25), except for the cognitive component (6 versus 2.5, p = 0.04). The on-treatment analyses (n = 30) yielded similar results (total FIM: 32 versus 26, p = 0.11; cognitive FIM: 6 versus 2, p = 0.06). Conclusions: A sham-controlled CPAP trial among stroke rehabilitation patients was feasible in terms of recruitment, treatment without diagnostic testing and adequate blinding—though was limited by study retention and CPAP adherence. Despite these limitations, a trend towards a benefit of CPAP on recovery was evident. Tolerance and adherence must be improved before the full benefits of CPAP on recovery can be assessed in larger trials. Citation: Khot SP, Davis AP, Crane DA, Tanzi PM, Li Lue D, Claflin ES, Becker KJ, Longstreth WT, Watson NF, Billings ME. Effect of continuous positive airway pressure on stroke rehabilitation: a pilot randomized sham-controlled trial. J Clin Sleep Med 2016;12(7):1019–1026. PMID

  18. Molecular docking studies of (1E,3E,5E)-1,6-Bis(substituted phenyl)hexa-1,3,5-triene and 1,4-Bis(substituted trans-styryl)benzene analogs as novel tyrosinase inhibitors.

    Science.gov (United States)

    Ha, Young Mi; Lee, Hye Jin; Park, Daeui; Jeong, Hyoung Oh; Park, Ji Young; Park, Yun Jung; Lee, Kyung Jin; Lee, Ji Yeon; Moon, Hyung Ryong; Chung, Hae Young

    2013-01-01

    We simulated the docking of the tertiary structure of mushroom tyrosinase with our compounds. From the structure-tyrosinase inhibitory activity relationship, it is notable that compounds 4, 8 and 11 showed similar or better activity rates than kojic acid which was used as a positive control. Compounds 17, 21, and 23 among benzene analogs that possess the same substituent showed significantly lower tyrosinase inhibitory effects. Therefore, we have confirmed that among the compounds showing better tyrosinase inhibitory effects than kojic acid, the compounds with triene analogs have better tyrosinase inhibitory effect than the compounds with benzene analogs. Docking simulation suggested the mechanism of compounds by several key residues which had possible hydrogen bonding interactions. The pharmacophore model underlined the features of active compounds, 4,4'-((1E,3E,5E)-hexa-1,3,5-triene-1,6-diyl)diphenol, 5,5'-((1E,3E,5E)-hexa-1,3,5-triene-1,6-diyl)bis(2-methoxy-phenol), and 5,5'-((1E,3E,5E)-hexa-1,3,5-triene-1,6-diyl)dibenzene-1,3-diol among triene derivatives which had several hydrogen bond groups on both terminal rings. The soundness of the docking results and the agreement with the pharmacophores suggest that it can be conveniently exploited to design inhibitors with an improved affinity for tyrosinase.

  19. Position controlled Knee Rehabilitation Orthotic Device for Patients after Total Knee Replacement Arthroplasty

    Science.gov (United States)

    Wannaphan, Patsiri; Chanthasopeephan, Teeranoot

    2016-11-01

    Knee rehabilitation after total knee replacement arthroplasty is essential for patients during their post-surgery recovery period. This study is about designing one degree of freedom knee rehabilitation equipment to assist patients for their post-surgery exercise. The equipment is designed to be used in sitting position with flexion/extension of knee in sagittal plane. The range of knee joint motion is starting from 0 to 90 degrees angle for knee rehabilitation motion. The feature includes adjustable link for different human proportions and the torque feedback control at knee joint during rehabilitation and the control of flexion/extension speed. The motion of the rehabilitation equipment was set to move at low speed (18 degrees/sec) for knee rehabilitation. The rehabilitation link without additional load took one second to move from vertical hanging up to 90° while the corresponding torque increased from 0 Nm to 2 Nm at 90°. When extra load is added, the link took 1.5 seconds to move to 90° The torque is then increased from 0 Nm to 4 Nm. After a period of time, the speed of the motion can be varied. User can adjust the motion to 40 degrees/sec during recovery activity of the knee and users can increase the level of exercise or motion up to 60 degrees/sec to strengthen the muscles during throughout their rehabilitation program depends on each patient. Torque control is included to prevent injury. Patients can use the equipment for home exercise to help reduce the number of hospital visit while the patients can receive an appropriate therapy for their knee recovery program.

  20. Sonographic evaluation of the fetal spine position and success rate of manual rotation of the fetus in occiput posterior position: A randomized controlled trial.

    Science.gov (United States)

    Masturzo, Bianca; Farina, Antonio; Attamante, Lorenza; Piazzese, Annalisa; Rolfo, Alessandro; Gaglioti, Pietro; Todros, Tullia

    2017-10-01

    To evaluate whether sonographic (US) diagnosis of the fetal spine position could increase the success rate of manual rotation of the fetal occiput (MRFO) in second-stage arrest in persistent occiput posterior position (OPP). In this randomized controlled parallel single-center trial, 58 nulliparous in second-stage arrest of labor with fetus in cephalic presentation and OPP diagnosed by US were randomly assigned to group A where the fetal spine position was not known by the operator or to group B where the operator knew it. The main outcome was the success of MRFO in the two groups. Secondary outcomes were perineal injuries, blood loss, duration of expulsive period, and neonatal APGAR at 5 minutes. A priori knowledge of the spine position improves the success of the MRFO (41.4% group A versus 82.8% group B, p value < 0.001), the percentage of spontaneous deliveries (27.6% group A versus 69% group B, p value = 0.01), and maternal outcome (intact perineum and blood loss). No differences were detected on the neonatal side. MRFO is a safe and useful procedure that should be performed in second-stage arrest in OPP. A better performance was observed when supported by the US knowledge of the spine position. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:472-476, 2017. © 2017 Wiley Periodicals, Inc.

  1. Positive affect and cognitive control: approach-motivation intensity influences the balance between cognitive flexibility and stability.

    Science.gov (United States)

    Liu, Ya; Wang, Zhenhong

    2014-05-01

    In most prior research, positive affect has been consistently found to promote cognitive flexibility. However, the motivational dimensional model of affect assumes that the influence of positive affect on cognitive processes is modulated by approach-motivation intensity. In the present study, we extended the motivational dimensional model to the domain of cognitive control by examining the effect of low- versus high-approach-motivated positive affect on the balance between cognitive flexibility and stability in an attentional-set-shifting paradigm. Results showed that low-approach-motivated positive affect promoted cognitive flexibility but also caused higher distractibility, whereas high-approach-motivated positive affect enhanced perseverance but simultaneously reduced distractibility. These results suggest that the balance between cognitive flexibility and stability is modulated by the approach-motivation intensity of positive affective states. Therefore, it is essential to incorporate motivational intensity into studies on the influence of affect on cognitive control.

  2. Positive lists of cosmetic ingredients: Analytical methodology for regulatory and safety controls – A review

    International Nuclear Information System (INIS)

    Lores, Marta; Llompart, Maria; Alvarez-Rivera, Gerardo; Guerra, Eugenia; Vila, Marlene; Celeiro, Maria; Lamas, J. Pablo; Garcia-Jares, Carmen

    2016-01-01

    Cosmetic products placed on the market and their ingredients, must be safe under reasonable conditions of use, in accordance to the current legislation. Therefore, regulated and allowed chemical substances must meet the regulatory criteria to be used as ingredients in cosmetics and personal care products, and adequate analytical methodology is needed to evaluate the degree of compliance. This article reviews the most recent methods (2005–2015) used for the extraction and the analytical determination of the ingredients included in the positive lists of the European Regulation of Cosmetic Products (EC 1223/2009): comprising colorants, preservatives and UV filters. It summarizes the analytical properties of the most relevant analytical methods along with the possibilities of fulfilment of the current regulatory issues. The cosmetic legislation is frequently being updated; consequently, the analytical methodology must be constantly revised and improved to meet safety requirements. The article highlights the most important advances in analytical methodology for cosmetics control, both in relation to the sample pretreatment and extraction and the different instrumental approaches developed to solve this challenge. Cosmetics are complex samples, and most of them require a sample pretreatment before analysis. In the last times, the research conducted covering this aspect, tended to the use of green extraction and microextraction techniques. Analytical methods were generally based on liquid chromatography with UV detection, and gas and liquid chromatographic techniques hyphenated with single or tandem mass spectrometry; but some interesting proposals based on electrophoresis have also been reported, together with some electroanalytical approaches. Regarding the number of ingredients considered for analytical control, single analyte methods have been proposed, although the most useful ones in the real life cosmetic analysis are the multianalyte approaches. - Highlights:

  3. Positive lists of cosmetic ingredients: Analytical methodology for regulatory and safety controls – A review

    Energy Technology Data Exchange (ETDEWEB)

    Lores, Marta, E-mail: marta.lores@usc.es; Llompart, Maria; Alvarez-Rivera, Gerardo; Guerra, Eugenia; Vila, Marlene; Celeiro, Maria; Lamas, J. Pablo; Garcia-Jares, Carmen

    2016-04-07

    Cosmetic products placed on the market and their ingredients, must be safe under reasonable conditions of use, in accordance to the current legislation. Therefore, regulated and allowed chemical substances must meet the regulatory criteria to be used as ingredients in cosmetics and personal care products, and adequate analytical methodology is needed to evaluate the degree of compliance. This article reviews the most recent methods (2005–2015) used for the extraction and the analytical determination of the ingredients included in the positive lists of the European Regulation of Cosmetic Products (EC 1223/2009): comprising colorants, preservatives and UV filters. It summarizes the analytical properties of the most relevant analytical methods along with the possibilities of fulfilment of the current regulatory issues. The cosmetic legislation is frequently being updated; consequently, the analytical methodology must be constantly revised and improved to meet safety requirements. The article highlights the most important advances in analytical methodology for cosmetics control, both in relation to the sample pretreatment and extraction and the different instrumental approaches developed to solve this challenge. Cosmetics are complex samples, and most of them require a sample pretreatment before analysis. In the last times, the research conducted covering this aspect, tended to the use of green extraction and microextraction techniques. Analytical methods were generally based on liquid chromatography with UV detection, and gas and liquid chromatographic techniques hyphenated with single or tandem mass spectrometry; but some interesting proposals based on electrophoresis have also been reported, together with some electroanalytical approaches. Regarding the number of ingredients considered for analytical control, single analyte methods have been proposed, although the most useful ones in the real life cosmetic analysis are the multianalyte approaches. - Highlights:

  4. Mouse obesity network reconstruction with a variational Bayes algorithm to employ aggressive false positive control

    Directory of Open Access Journals (Sweden)

    Logsdon Benjamin A

    2012-04-01

    Full Text Available Abstract Background We propose a novel variational Bayes network reconstruction algorithm to extract the most relevant disease factors from high-throughput genomic data-sets. Our algorithm is the only scalable method for regularized network recovery that employs Bayesian model averaging and that can internally estimate an appropriate level of sparsity to ensure few false positives enter the model without the need for cross-validation or a model selection criterion. We use our algorithm to characterize the effect of genetic markers and liver gene expression traits on mouse obesity related phenotypes, including weight, cholesterol, glucose, and free fatty acid levels, in an experiment previously used for discovery and validation of network connections: an F2 intercross between the C57BL/6 J and C3H/HeJ mouse strains, where apolipoprotein E is null on the background. Results We identified eleven genes, Gch1, Zfp69, Dlgap1, Gna14, Yy1, Gabarapl1, Folr2, Fdft1, Cnr2, Slc24a3, and Ccl19, and a quantitative trait locus directly connected to weight, glucose, cholesterol, or free fatty acid levels in our network. None of these genes were identified by other network analyses of this mouse intercross data-set, but all have been previously associated with obesity or related pathologies in independent studies. In addition, through both simulations and data analysis we demonstrate that our algorithm achieves superior performance in terms of power and type I error control than other network recovery algorithms that use the lasso and have bounds on type I error control. Conclusions Our final network contains 118 previously associated and novel genes affecting weight, cholesterol, glucose, and free fatty acid levels that are excellent obesity risk candidates.

  5. Positive lists of cosmetic ingredients: Analytical methodology for regulatory and safety controls - A review.

    Science.gov (United States)

    Lores, Marta; Llompart, Maria; Alvarez-Rivera, Gerardo; Guerra, Eugenia; Vila, Marlene; Celeiro, Maria; Lamas, J Pablo; Garcia-Jares, Carmen

    2016-04-07

    Cosmetic products placed on the market and their ingredients, must be safe under reasonable conditions of use, in accordance to the current legislation. Therefore, regulated and allowed chemical substances must meet the regulatory criteria to be used as ingredients in cosmetics and personal care products, and adequate analytical methodology is needed to evaluate the degree of compliance. This article reviews the most recent methods (2005-2015) used for the extraction and the analytical determination of the ingredients included in the positive lists of the European Regulation of Cosmetic Products (EC 1223/2009): comprising colorants, preservatives and UV filters. It summarizes the analytical properties of the most relevant analytical methods along with the possibilities of fulfilment of the current regulatory issues. The cosmetic legislation is frequently being updated; consequently, the analytical methodology must be constantly revised and improved to meet safety requirements. The article highlights the most important advances in analytical methodology for cosmetics control, both in relation to the sample pretreatment and extraction and the different instrumental approaches developed to solve this challenge. Cosmetics are complex samples, and most of them require a sample pretreatment before analysis. In the last times, the research conducted covering this aspect, tended to the use of green extraction and microextraction techniques. Analytical methods were generally based on liquid chromatography with UV detection, and gas and liquid chromatographic techniques hyphenated with single or tandem mass spectrometry; but some interesting proposals based on electrophoresis have also been reported, together with some electroanalytical approaches. Regarding the number of ingredients considered for analytical control, single analyte methods have been proposed, although the most useful ones in the real life cosmetic analysis are the multianalyte approaches. Copyright © 2016

  6. Four-arm single docking full robotic surgery for low rectal cancer: technique standardization

    Directory of Open Access Journals (Sweden)

    José Reinan Ramos

    Full Text Available The authors present the four-arm single docking full robotic surgery to treat low rectal cancer. The eight main operative steps are: 1- patient positioning; 2- trocars set-up and robot docking; 3- sigmoid colon, left colon and splenic flexure mobilization (lateral-to-medial approach; 4-Inferior mesenteric artery and vein ligation (medial-to-lateral approach; 5- total mesorectum excision and preservation of hypogastric and pelvic autonomic nerves (sacral dissection, lateral dissection, pelvic dissection; 6- division of the rectum using an endo roticulator stapler for the laparoscopic performance of a double-stapled coloanal anastomosis (type I tumor; 7- intersphincteric resection, extraction of the specimen through the anus and lateral-to-end hand sewn coloanal anastomosis (type II tumor; 8- cylindric abdominoperineal resection, with transabdominal section of the levator muscles (type IV tumor. The techniques employed were safe and have presented low rates of complication and no mortality.

  7. Passive hybrid force-position control for tele-operation based on real-time simulation of a virtual mechanism

    International Nuclear Information System (INIS)

    Joly, L.; Andriot, C.

    1995-01-01

    Hybrid force-position control aims at controlling position and force in separate directions. It is particularly useful to perform certain robotic tasks. In tele-operation context, passivity is important because it ensures stability when the system interacts with any passive environment. In this paper, we propose an original approach to hybrid force-position control of a force reflecting tele-robot system. It is based on real-time simulation of a virtual mechanism corresponding to the task. the resulting control law is passive. Experiments on a 6 degrees of freedom tele-operation system consisting in following a bent pipe under several control modes validate the approach. (authors). 12 refs., 6 figs

  8. Molecular Docking and Anticonvulsant Activity of Newly Synthesized Quinazoline Derivatives

    Directory of Open Access Journals (Sweden)

    Hatem A. Abuelizz

    2017-06-01

    Full Text Available A new series of quinazoline-4(3H-ones are evaluated for anticonvulsant activity. After intraperitoneal (ip injection to albino mice at a dose of 100 mg/kg body weight, synthesized quinazolin-4(3H-ones (1–24 were examined in the maximal electroshock (MES induced seizures and subcutaneous pentylenetetrazole (scPTZ induced seizure models in mice. The Rotarod method was applied to determine the neurotoxicity. Most of the compounds displayed anticonvulsant activity in the scPTZ screen at a dose range of 0.204–0.376 mmol/mL. Out of twenty-four, compounds 8, 13 and 19 proved to be the most active with a remarkable protection (100% against PTZ induced convulsions and four times more potent activity than ethosuximide. The structure-activity relationship concluded valuable pharmacophoric information, which was confirmed by the molecular docking studies using the target enzyme human carbon anhydrase II (HCA II. The studied quinazoline analogues suggested that the butyl substitution at position 3 has a significant effect on preventing the spread of seizure discharge and on raising the seizure threshold. However, benzyl substitution at position 3 has shown a strong anticonvulsant activity but with less seizure prevention compared to the butyl substitution.

  9. Relative position control and coalescence of independent microparticles using ultrasonic waves

    Science.gov (United States)

    Deng, Shuang; Jia, Kun; Chen, Jian; Mei, Deqing; Yang, Keji

    2017-05-01

    Controlling the relative positions and coalescence of independent cells or microparticles is of particular importance for studying many physical phenomena, biological research, pharmaceutical tests, and chemical material processing. In this work, contactless maneuvering of two independent microparticles initially lying on a rigid surface was performed at a stable levitation height within a water-filled ultrasonic chamber. Three lead zirconate titanate transducers with 2 MHz thickness resonance frequency were obliquely mounted in a homemade device to form a sound field in a half space. By modulating the excitation voltage of a single transducer and the subsequent combination of amplitude and phase modulation, two separate 80 μm diameter silica beads were picked up from the chamber bottom, approached, and then coalesced to form a cluster in different ways. Both particles simultaneously migrated towards each other in the former process, while more dexterous movement with single-particle migration was realized for the other process. There is good agreement between the measured trajectories and theoretical predictions based on the theory of the first-order acoustic radiation force. The method introduced here also has the ability to form a cluster at any desired location in the chamber, which is promising for macromolecule processing ranging from the life sciences to biochemistry and clinical practice.

  10. A positional code and anisotropic forces control tissue remodeling in Drosophila

    Science.gov (United States)

    Zallen, Jennifer

    A major challenge in developmental biology is to understand how tissue-scale changes in organism structure arise from events that occur on a cellular and molecular level. We are using cell biological, biophysical, and quantitative live-embryo imaging approaches to understand how genes encode the forces that shape tissues, and to identify the mechanisms that modulate cell behavior in response to local forces. In many animals, the elongated head-to-tail body axis is achieved by rapid and coordinated movements of hundreds of cells. We found that in the fruit fly, these cell movements are regulated by subcellular asymmetries in the localization of proteins that generate contractile and adhesive forces between cells. Asymmetries in the force-generating machinery are in turn controlled by a positional code of spatial information provided by an ancient family of Toll-related receptors that are widely used for pathogen recognition by the innate immune system. I will describe how this spatial system systematically orients local cell movements and collective rosette-like clusters in the Drosophila embryo. Rosettes have now also been shown to shape the body axis in chicks, frogs, and mice, demonstrating that rosette behaviors are a general mechanism linking cellular asymmetry to tissue reorganization.

  11. Cocoa polyphenols enhance positive mood states but not cognitive performance: a randomized, placebo-controlled trial.

    Science.gov (United States)

    Pase, Matthew P; Scholey, Andrew B; Pipingas, Andrew; Kras, Marni; Nolidin, Karen; Gibbs, Amy; Wesnes, Keith; Stough, Con

    2013-05-01

    This study aimed to examine the acute and sub-chronic effects of cocoa polyphenols on cognition and mood. In a randomized, double-blind study, healthy middle-aged participants received a dark chocolate drink mix standardized to contain 500 mg, 250 mg or 0 mg of polyphenols (placebo) in a parallel-groups design. Participants consumed their assigned treatment once daily for 30 days. Cognition was measured with the Cognitive Drug Research system and self-rated mood with the Bond-Lader Visual Analogue Scale. Participants were tested at baseline, at 1, 2.5 and 4 h after a single acute dose and again after receiving 30 days of treatment. In total, 72 participants completed the trial. After 30 days, the high dose of treatment significantly increased self-rated calmness and contentedness relative to placebo. Mood was unchanged by treatment acutely while cognition was unaffected by treatment at all time points. This randomized controlled trial is perhaps the first to demonstrate the positive effects of cocoa polyphenols on mood in healthy participants. This provides a rationale for exploring whether cocoa polyphenols can ameliorate the symptoms associated with clinical anxiety or depression.

  12. Dynamic Docking: A Paradigm Shift in Computational Drug Discovery

    Directory of Open Access Journals (Sweden)

    Dario Gioia

    2017-11-01

    Full Text Available Molecular docking is the methodology of choice for studying in silico protein-ligand binding and for prioritizing compounds to discover new lead candidates. Traditional docking simulations suffer from major limitations, mostly related to the static or semi-flexible treatment of ligands and targets. They also neglect solvation and entropic effects, which strongly limits their predictive power. During the last decade, methods based on full atomistic molecular dynamics (MD have emerged as a valid alternative for simulating macromolecular complexes. In principle, compared to traditional docking, MD allows the full exploration of drug-target recognition and binding from both the mechanistic and energetic points of view (dynamic docking. Binding and unbinding kinetic constants can also be determined. While dynamic docking is still too computationally expensive to be routinely used in fast-paced drug discovery programs, the advent of faster computing architectures and advanced simulation methodologies are changing this scenario. It is feasible that dynamic docking will replace static docking approaches in the near future, leading to a major paradigm shift in in silico drug discovery. Against this background, we review the key achievements that have paved the way for this progress.

  13. Emotional modulation of control dilemmas: the role of positive affect, reward, and dopamine in cognitive stability and flexibility.

    Science.gov (United States)

    Goschke, Thomas; Bolte, Annette

    2014-09-01

    Goal-directed action in changing environments requires a dynamic balance between complementary control modes, which serve antagonistic adaptive functions (e.g., to shield goals from competing responses and distracting information vs. to flexibly switch between goals and behavioral dispositions in response to significant changes). Too rigid goal shielding promotes stability but incurs a cost in terms of perseveration and reduced flexibility, whereas too weak goal shielding promotes flexibility but incurs a cost in terms of increased distractibility. While research on cognitive control has long been conducted relatively independently from the study of emotion and motivation, it is becoming increasingly clear that positive affect and reward play a central role in modulating cognitive control. In particular, evidence from the past decade suggests that positive affect not only influences the contents of cognitive processes, but also modulates the balance between complementary modes of cognitive control. In this article we review studies from the past decade that examined effects of induced positive affect on the balance between cognitive stability and flexibility with a focus on set switching and working memory maintenance and updating. Moreover, we review recent evidence indicating that task-irrelevant positive affect and performance-contingent rewards exert different and sometimes opposite effects on cognitive control modes, suggesting dissociations between emotional and motivational effects of positive affect. Finally, we critically review evidence for the popular hypothesis that effects of positive affect may be mediated by dopaminergic modulations of neural processing in prefrontal and striatal brain circuits, and we refine this "dopamine hypothesis of positive affect" by specifying distinct mechanisms by which dopamine may mediate effects of positive affect and reward on cognitive control. We conclude with a discussion of limitations of current research, point to

  14. Controlling thermal chaos in the mantle by positive feedback from radiative thermal conductivity

    Directory of Open Access Journals (Sweden)

    F. Dubuffet

    2002-01-01

    Full Text Available The thermal conductivity of mantle materials has two components, the lattice component klat from phonons and the radiative component krad due to photons. These two contributions of variable thermal conductivity have a nonlinear dependence in the temperature, thus endowing the temperature equation in mantle convection with a strongly nonlinear character. The temperature derivatives of these two mechanisms have different signs, with ∂klat /∂T negative and dkrad /dT positive. This offers the possibility for the radiative conductivity to control the chaotic boundary layer instabilities developed in the deep mantle. We have parameterized the weight factor between krad and klat with a dimensionless parameter f , where f = 1 corresponds to the reference conductivity model. We have carried out two-dimensional, time-dependent calculations for variable thermal conductivity but constant viscosity in an aspect-ratio 6 box for surface Rayleigh numbers between 106 and 5 × 106. The averaged Péclet numbers of these flows lie between 200 and 2000. Along the boundary in f separating the chaotic and steady-state solutions, the number decreases and the Nusselt number increases with internal heating, illustrating the feedback between internal heating and radiative thermal conductivity. For purely basal heating situation, the time-dependent chaotic flows become stabilized for values of f of between 1.5 and 2. The bottom thermal boundary layer thickens and the surface heat flow increases with larger amounts of radiative conductivity. For magnitudes of internal heating characteristic of a chondritic mantle, much larger values of f , exceeding 10, are required to quench the bottom boundary layer instabilities. By isolating the individual conductive mechanisms, we have ascertained that the lattice conductivity is partly responsible for inducing boundary layer instabilities, while the radiative conductivity and purely depth-dependent conductivity exert a stabilizing

  15. Molecular docking study of Papaver alkaloids to some alkaloid receptors

    Directory of Open Access Journals (Sweden)

    A. Nofallah

    2017-11-01

    Full Text Available Background and objectives: More than 40 different alkaloids have been obtained from opium the most important of which are morphine, codeine, papaverine, noscapine and tabaine. Opioid alkaloids produce analgesia by affecting areas of the brain that have peptides with pharmacological pseudo-opioid properties. These alkaloids show important effects on some intracellular peptides like mu, delta, and kappa receptors. Therefore, studying the effects of these alkaloids on different receptors is essential. Methods: Molecular docking is a well-known method in exploring the protein-ligand interactions. In this research, five important alkaloids were docked to crystal structure of human mu opioid receptor (4DKL, human delta opioid receptor (4EJ4 and human kappa opioid receptor (4DJH which were retrieved from protein databank. The 3D-structures of alkaloids were drawn by chembiooffice2010 and minimized with hyperchem package and submitted to molecular docking utilizing autodock-vina. Flexibility of the proteins was considered. The docking studies were performed to compare the affinity of these five alkaloids to the mentioned receptors. Results: We computationally docked each alkaloid compound onto each receptor structure and estimated their binding affinity based on dock scores. Dock score is a criteria including binding energy which utilized here for prediction and comparison of the binding affinities. Binding interactions of the docked alkaloids in receptor pockets were also visually inspected and compared. Conclusion: In this approach, using docking study as a computational method provided a valuable insight of opioid receptor pocket structures which would be essential to design more efficient drugs in pain managements and addiction treatments.

  16. Sequence alignment reveals possible MAPK docking motifs on HIV proteins.

    Directory of Open Access Journals (Sweden)

    Perry Evans

    Full Text Available Over the course of HIV infection, virus replication is facilitated by the phosphorylation of HIV proteins by human ERK1 and ERK2 mitogen-activated protein kinases (MAPKs. MAPKs are known to phosphorylate their substrates by first binding with them at a docking site. Docking site interactions could be viable drug targets because the sequences guiding them are more specific than phosphorylation consensus sites. In this study we use multiple bioinformatics tools to discover candidate MAPK docking site motifs on HIV proteins known to be phosphorylated by MAPKs, and we discuss the possibility of targeting docking sites with drugs. Using sequence alignments of HIV proteins of different subtypes, we show that MAPK docking patterns previously described for human proteins appear on the HIV matrix, Tat, and Vif proteins in a strain dependent manner, but are absent from HIV Rev and appear on all HIV Nef strains. We revise the regular expressions of previously annotated MAPK docking patterns in order to provide a subtype independent motif that annotates all HIV proteins. One revision is based on a documented human variant of one of the substrate docking motifs, and the other reduces the number of required basic amino acids in the standard docking motifs from two to one. The proposed patterns are shown to be consistent with in silico docking between ERK1 and the HIV matrix protein. The motif usage on HIV proteins is sufficiently different from human proteins in amino acid sequence similarity to allow for HIV specific targeting using small-molecule drugs.

  17. Development of three methods for control rod position monitoring based on fixed in-core neutron detectors

    International Nuclear Information System (INIS)

    Peng, Xingjie; Li, Qing; Wang, Kan

    2015-01-01

    Highlights: • Three methods are utilized separately to unfold the control rod position from the fixed in-core neutron detector measurements. • Fixed in-core neutron detector measurements are simulated by neutronics code SMART. • Numerical results show that all these methods can unfold the control rod position accurately. • Two correction strategies are proposed to correct the simulated fixed in-core detector signals. - Abstract: Nuclear reactor core power distribution on-line monitoring system is very important in core surveillance, and this system should have the ability to indicate some abnormal conditions, such as the unacceptable control rod misalignment. In this study, the methodologies of radial basis function neural network (RBFNN), group method of data handling (GMDH) and Levenberg–Marquardt (LM) algorithm are utilized separately to unfold the control rod position from the fixed in-core neutron detector measurements. For using these methods, a large number of in-core detector signals corresponding to various known rod positions are needed. These data can be generated by an advanced core calculation code. In this study, the neutronics code SMART was used. The simulation results show that all these methods can unfold the control rod position accurately, and the performance comparison shows that the regularized RBFNN performs best. Two correction strategies are proposed to correct the simulated fixed in-core detector signals and improve the rod position monitoring accuracy when there are mismatches between actual physical factors and modeled physical factors

  18. Development of a stable positive control to be used for quality assurance of rapid diagnostic tests for malaria

    NARCIS (Netherlands)

    Versteeg, Inge; Mens, Petra F.

    2009-01-01

    The objective of this study is to develop and evaluate a simple, cheap, and stable positive control for the quality control and quality assurance (QA) of rapid diagnostic tests (RDT) for the diagnosis of malaria. Plasmodium falciparum in vitro culture of known parasite concentrations was dried on a

  19. Effects of Modes, Obesity, and Body Position on Non-invasive Positive Pressure Ventilation Success in the Intensive Care Unit: A Randomized Controlled Study.

    Science.gov (United States)

    Türk, Murat; Aydoğdu, Müge; Gürsel, Gül

    2018-01-01

    Different outcomes and success rates of non-invasive positive pressure ventilation (NPPV) in patients with acute hypercapnic respiratory failure (AHRF) still pose a significant problem in intensive care units. Previous studies investigating different modes, body positioning, and obesity-associated hypoventilation in patients with chronic respiratory failure showed that these factors may affect ventilator mechanics to achieve a better minute ventilation. This study tried to compare pressure support (BiPAP-S) and average volume targeted pressure support (AVAPS-S) modes in patients with acute or acute-on-chronic hypercapnic respiratory failure. In addition, short-term effects of body position and obesity within both modes were analyzed. We conducted a randomized controlled study in a 7-bed intensive care unit. The course of blood gas analysis and differences in ventilation variables were compared between BiPAP-S (n=33) and AVAPS-S (n=29), and between semi-recumbent and lateral positions in both modes. No difference was found in the length of hospital stay and the course of PaCO2, pH, and HCO3 levels between the modes. There was a mean reduction of 5.7±4.1 mmHg in the PaCO2 levels in the AVAPS-S mode, and 2.7±2.3 mmHg in the BiPAP-S mode per session (ppositioning had no notable effect in both modes. Although the decrease in the PaCO2 levels in the AVAPS-S mode per session was remarkably high, the course wa